Good evening, everyone. My name is Shannon Strader, and I'm a PGY1 at the University of Louisville. I first wanted to thank all of you those who attended tonight. I'm very excited to be introducing the newest AAP and AR3T webinar series, the Orthobiologics and RegenMed series. The goal for these webinars are to provide comprehensive education for physicians in training and physiatrists interested in regenerative rehab, while reducing stigma, misinformation and encouraging responsible advancements for the regenerative field. During the talk, you may write any questions you have in the chat, and we will answer as many as time permits in the AAP end. It gives me great pleasure to introduce our first speaker, the amazing Dr. Allison Bean. Dr. Bean is an assistant professor at the University of Pittsburgh Medical Center. She completed her MD-PhD training at the University of Pittsburgh and her PM&R residency at the Icahn School of Medicine at Mount Sinai in New York City. She then returned to UPMC to complete a sports med fellowship. In addition to her clinical sports medicine practice, she is currently conducting basic science and translational research focused on the development of novel regenerative rehab therapies to improve treatment of muscle and tendon injuries. Thank you so much for being our first speaker, Dr. Bean. I look forward to hearing from you. Thank you, Dr. Schroeder, for that kind introduction, and to you, the AAP, and AR3T for helping to organize this webinar series. And thanks, of course, to everyone that's tuning in tonight, taking time out of your evening or late afternoon if you're on the West Coast. It's quite an honor to be asked to kick off these lectures, considering the stars in the field that we'll be presenting in the coming months. I hope to set the stage tonight for subsequent lectures by providing a very basic overview of what regenerative medicine and orthobiologics are and the current state of clinical applications. Certainly what I talk about here will just be the tip of the iceberg, so for those of you who are excited to learn more, I highly encourage you to join subsequent lectures in the series. All right, so let's get started. I don't have any financial disclosures or any conflicts of interest. However, I do want to mention that I will be discussing off-label uses of drugs and devices tonight. So incredible advances in science and medicine have resulted in an increase in life expectancy from approximately 40 years of age in the late 1800s up beyond 70 years of age, as of a few years ago. However, this remarkable decrease in mortality has not come with an absence of morbidity. As you can see in this graph on the right, with the y-axis showing percentage of individuals and the x-axis showing basically 10-year age brackets, we see that in the light blue, that percentage of individuals with disability continues to increase with increasing age, thus suggesting that age itself is a significant risk factor for developing disability. In the field of physical medicine and rehabilitation, we are particularly aware of the negative impact of disability on our patient's quality of life, whether it is acquired with age or congenital. This chart here shows the top 10 causes of disability among U.S. adults in 2005. We see that the most common causes of disability are conditions that typically increase in prevalence with age, including arthritis, cardiac disease, lung disease, diabetes, and stroke. Finding ways that help to decrease the prevalence of these conditions, or at least decrease the disability that they cause, is important in order to reduce the personal, societal, and economic burden of disease, particularly as our global population continues to rapidly age. All right, when we are young, we typically have an excellent ability to repair or regenerate many of our organs or tissues. However, as we age or progress through disease, this ability to regenerate becomes impaired. A great deal of research has been conducted investigating the biological mechanisms that underlie tissue aging, and many of the pathways, many different pathways have been found to be affected. This includes changes to DNA structure itself, gene expression, and translation, as well as progressive mitochondrial dysfunction, which leads to cellular injury and apoptosis. Increasing age also causes impairment of cell division, which is known as cellular senescence, as well as stem cell exhaustion, which is an age-related deficiency in the number of stem cells. With increasing dysfunction from one or more of these underlying changes, a shift occurs away from cell and tissue regeneration towards progressive degeneration. As scientists have begun to understand more about how aging occurs, research has become increasingly focused on how to prevent these changes. Essentially, we are searching for the biological fountain of youth. If we can prevent these changes, if we can either slow or reverse the negative effects of aging, will we be able to not only live longer, but perhaps more importantly, have improved health and physical function throughout our lifespan? And this is the basic question that regenerative medicine seeks to answer. So what exactly is regenerative medicine? While there have been many definitions put forth, I have found this one by Mason and Dunnell, presented in 2007, to be sufficiently broad, while also remaining quite clear and concise. They state that regenerative medicine replaces or regenerates human cells, tissues, or organs in order to restore or establish normal function. Despite the fact that I've begun the lecture by focusing on aging, I like this definition of regenerative medicine because it specifically states that regenerative medicine includes both restoration of normal function, as well as establishment of normal function that may never have been present. We certainly know that tissue dysfunction is not limited to aging, but also includes progression of congenital diseases, as well as acquired conditions at younger ages. And regenerative medicine has the potential to radically change the course of these conditions as well. To dive a bit deeper, another way to look at this is to apply the R3 regenerative medicine paradigm that was described by Nelson et al. in 2008. This addresses three generally different approaches to establishing a functional tissue. The three R's here are replacement, regeneration, and rejuvenation. These three concepts certainly overlap quite a bit in practice, but can also be defined individually to a certain extent. So first, replacement focuses on restoring or establishing function by implantation of new organs, whether it is a native organ obtained from another individual, either living or deceased, or one that has been tissue engineered using a combination of biomaterials and cells. Regardless of the origin, with replacement, the implanted organ takes over function of the diseased or absent tissue. Regeneration, on the other hand, utilizes transplantation of progenitor cells that become engrafted into the native tissue and promote restoration of functional tissues through proliferation and differentiation of the transplanted cells. This approach, in particular, may help to overcome stem cell exhaustion. Finally, the third R is rejuvenation. Rejuvenation restores tissues to a more youthful state, typically by activation of already existing resident stem cells through either biological or pharmacological treatments. Once activated, the stem cells can divide, differentiate, stimulate deposition of extracellular matrix proteins in order to re-establish tissue structure and function. This approach may be particularly effective in the setting of cellular senescence, as I described before. Now that we understand what regenerative medicine is, I want to take you briefly through some of the historical achievements, as I think it helps to understand how scientific discovery has progressed over the years in order to appreciate where we are at today. This is certainly not a comprehensive list of advances, but just a small selection of those that I think are most important. So interest in tissue regeneration began at least as far back as ancient Greece. I'm sure that many of you know the story of Prometheus, who was a Greek god, the Greek god of fire, who stole fire and gave it to humans. As a punishment, Zeus had him bound to a rock, and each day an eagle was sent to eat away Prometheus's liver. The liver would subsequently regrow, and he would just have to suffer the same fate the following day. This suggests that even in these ancient times, humans were aware that the liver is one of the few human organs capable of regeneration. Fast-forwarding about 25 centuries later, the regenerative medicine research was formally born during the 18th century, as several scientists observed that animals, including crawfish, hydra, as seen here in this first figure, salamanders, as well as snails, among other mostly amphibious creatures, were capable of regenerating either their limbs, their tails, or even their heads. Moving quickly forward again, the 20th century saw significant advances in regenerative medicine, particularly in the field of organ transplantation. The first successful kidney transplant was performed in 1954 in Boston, where the kidney of one identical twin was transplanted into his brother, thus avoiding any issues with immune rejection, and this is a picture of them here. Bone marrow transplantation from first degree family members followed soon after, along with other organ transplants that were successful. However, transplant of organs particularly took off during the 1980s, once immunosuppressive drugs were developed. The mid to late 1900s also saw the emergence of stem cell research. While the discovery of stem cells is actually debated, in 1961, Till and McCullough, who were at the University of Toronto, were the first to demonstrate in their seminal paper the existence of hematopoietic stem cells, or blood stem cells. They showed that these cells in particular were capable of self-renewal or cloning, and also had the capability to differentiate into other types of cells as well. And these two characteristics, the self-renewal and the multiple differentiation, are key characteristics of stem cells as we define them today. Stem cell research continued to progress throughout the 20th century, and in 1928 took a large leap forward when James Thompson and his group from the University of Wisconsin were the first to isolate embryonic stem cells for humans. And then again, another advancement was taken in 2006 with the development of induced pluripotent stem cells by Yamanaka. If you aren't familiar with embryonic stem cells or induced pluripotent stem cells, just hang on tight and I'll go into these in more detail in a few minutes. In the last 20 years, we began to see the beginning of clinical translation of regenerative therapies that utilize stem cells as well as tissue engineering. In 2006, Tony Atala from Wake Forest published a paper in The Lancet describing successful implantation of tissue engineered bladders into semi-young patients with myelomeningocele who had developed bladder dysfunction. The bladders were created using a collagen or collagen and polyglycolic acid scaffold and seeded with cells that were isolated from the patients. These tissue engineered bladders were then implanted back into the patients after cell seeding, and the paper was actually published several years after the surgery. And the paper was published in several years after the surgeries, and all patients had done extremely well. In 2011, the FDA approved Hemochord, which is a hematopoietic progenitor cell, which is isolated from human umbilical cord blood. And this is important because it was the first FDA approval of an allogeneic, which means obtained from another individual stem cell product. Then in 2018, quite recently, the first embryonic stem cell product was approved in Europe. This product, which is called Holoclar, actually uses embryonic stem cells as a retinal pigment epithelium patch in order to treat severe limbal stem cell deficiency that is often caused by burns. I do want to point out quickly that at this time, hematopoietic stem cells such as Hemochord and other similar types of products remain the only stem cells that are currently approved by the FDA. So as you can see with these historical achievements, regenerative medicine can involve many different approaches. These extend from organ transplantation to cell and tissue engineering, as well as genetic engineering and cloning. However, as research progresses, it appears that most scientists believe that stem cells, perhaps combined with one or more of these other components, are likely to hold the key for success in regenerative medicine. Because of this, I want to take a few minutes to go through some basic definitions that are pertinent to stem cell biology and research. So what are stem cells? Many of you probably learned about this either in undergraduate or medical school, but I think it's important to at least give a quick refresher. As I mentioned before, stem cells are defined by a couple of primary characteristics. First, they must be at least multipotent, which means they have the ability to differentiate and to suffer different cell types. They must also be self-renewing, which means that they can indefinitely divide to give rise to the same cell type, or in other words, they're able to clone themselves. While stem cells must be multipotent, they can also be what we call totipotent or pluripotent. Totipotency means that cells can give rise to complete embryo, including the placenta, while pluripotent cells, on the other hand, lose the capability of creating those embryonic tissues and instead can only divide into cell types that make up the body. Embryonic stem cells, as mentioned before, are considered pluripotent, as they can give rise to all three germ letters. And as I mentioned before, in addition to embryonic stem cells, which are found in normal fetuses, another type of embryonic-like stem cell known as induced pluripotent stem cells have been created through viral transfection of very specific transcription factors, which you can see here. And after transfection, these stem cells take on the characteristics of embryonic stem cells, hence their name. Embryonic stem cells, of course, are quite powerful since they can differentiate into any tissue, but they are also, of course, quite controversial as they're derived from fetal tissues that are destroyed in the process. Induced pluripotent stem cells, or iPS cells, provide an opportunity to circumvent this issue as they are developed from adult tissues. Kind of moving down the chart, as fetal development progresses, embryonic stem cells begin to divide to become the multipotent stem cells that are found in adult tissues. There are many different types of multipotent stem cells, but those most relevant to musculoskeletal conditions are the mesenchymal stem cells, or MSCs. MSCs can differentiate into many different types of musculoskeletal tissues, including bone, cartilage, tendon, ligament, muscle, as well as more supportive tissues, such as skin and adipose tissue. Thus, much orthopedic and rehabilitation for generative medicine research focuses on the use of MSCs, either through transplanting them directly into tissues or utilizing them in the development of tissue-engineered musculoskeletal tissues. As regenerative medicine research on MSCs has progressed, understanding of the mechanisms through which these cells act has begun to evolve. MSCs can, of course, be expanded and differentiated in vitro. And initially, it was thought that the way the MSCs worked was they simply home to the site of injury, became engrafted within tissues, and subsequently developed into the surrounding However, research has shown that with injection or even targeted engraftment with biomaterials, that the actual engraftment into the tissue is quite limited, and that the MSC-induced regeneration process actually likely occurs through other mechanisms. In particular, researchers have found that MSCs have paracrine effects, which essentially is when they have effects on the surrounding tissues, and that this is mediated by secretion of growth factors, as well as extracellular vesicles that induce extracellular matrix deposition, as well as the release of chemokines, which recruit cells from the surrounding areas. MSCs also seem to have quite potent immunomodulatory effects that can help to create a more supportive and regenerative surrounding environment. Because of the apparent importance of these paracrine effects, rather than direct cell engraftment, it was suggested recently in 2017 by Arnie Kaplan, who was the person who discovered these cells, that we stopped calling them mosaicable stem cells, but rather referred to them as medicinal signaling cells to more accurately describe their action. Okay, now that I've taken you through a bit of the basic science, let's discuss some of what's going on clinically. Okay, currently there's over 6,000 active stem cell trials registered from around the world, and over 3,200 of those are found in the United States. When selecting a few conditions that many of the patients that physiatrists have, many of the conditions that patients of physiatrists have, we find that there are currently 39 active trials for spinal cord injury research using stem cells, 38 for brain injury, and then over 200 for musculoskeletal injury. So you can see that it is quite popular. It should be pointed out, though, that the vast majority of these trials are small phase one or phase two trials, and larger phase three trials will certainly be needed to obtain FDA approval in the future. And something I will kind of bring up several times, but I think it's really important to make this point as we move forward, is that stem cells are not currently FDA approved for any orthopedic application. There will be additional lectures in this series that will go into depth about FDA regulation of biologics. However, I wanted to make at least this point clear early on so that everyone is aware of the regulatory limitations. So now we're going to shift gears from regenerative medicine to orthobiologics. So what likely pops into many of your heads when you hear the term regenerative medicine, at least before you attended this lecture, is actually orthobiologics. There is no formal definition of orthobiologics. However, they have been generally described as biological substances used to improve healing of musculoskeletal tissues. This includes various tissues, including cartilage, bone, tendon, ligament, and muscle. While ideally, orthobiologics would become synonymous with regenerative therapeutics, unfortunately, because the mechanism of action as well as the efficacy of these substances remains relatively unclear, I, as well as others, are often hesitant to really combine these into the same category. I believe that some of this is in part due to the fact that clinical use of these drugs has rapidly outpaced both clinical science research as well as clinical trials. This has led to a great deal of confusion, both among patients as well as clinicians, regarding the true state of the science. Additionally, as most orthobiologic products are not FDA-approved, these drugs are not covered by insurance and thus require out-of-pocket payments that can vary widely, from hundreds to thousands to tens of thousands of dollars. What is clear about orthobiologics is that there is a huge market that continues to grow. Worldwide, in 2018, the market was worth almost $6 billion, when over a third of that was coming from North America. And it is predicted that this will continue to grow rapidly over the next several years. So I just want to give some examples, and this is not exhaustive, but these are kind of the common ones that we hear about of clinically used orthobiologics. There are autologous products, which are derived from the patient's own tissues, and non-autologous products, which are either lab, are processed in the laboratory, or come from allografts, which are isolated from other individuals. So some of the most common autologous products, which probably most people have heard about, are platelet-rich plasma, bone marrow aspirate concentrate, microfragmented adipose tissue, um, and we won't talk about it today, but it's also, um, it, well, we'll skip that, and as well as autologous chondrocyte implantation. Non-autologous products that are used clinically are prolotherapy, which is typically dextrose, hyaluronic acid, also known as viscose supplementation, amniotic and placenta allografts, as well as bone allografts, which are commonly used surgically. The only orthobiologic that is FDA approved for point-of-care injection procedures is hyaluronic acid, and even this is only approved for, is approved only for knee osteoarthritis, and in fact, it's actually falling out of favor with some organizations, with, um, the American Academy of Orthopedic Surgeons, or AALS, um, ending their, um, recommendation for use of hyaluronic acid due to weak supporting evidence of its efficacy. So the, I'm gonna, I, this could be, you know, hours upon hours of lecture, but today I'm going to focus on, briefly, on three of these products that, um, I'll wait till they get muted. All right, so, uh, the ones I want to focus on today are platelet-rich plasma, a bone marrow aspirate concentrate, and microfragmented adipose tissue. So, platelet-rich plasma, or PRP, is loosely defined as, um, a, as plasma with a higher than physiologic concentration of platelets. Uh, the FDA typically defines it as having a constitution of greater than 250,000, uh, platelets per ml. Um, the way platelet-rich plasma is traditionally obtained is by isolating, uh, venous whole blood, uh, which is then centrifuged, uh, and centrifugation ends up, uh, separating this into three separate layers. On the bottom, you have your red blood cells, and then you have a small buffy coat layer, as well as a, um, upper layer, which consists mostly of plasma. Your platelets, as well as your leukocytes, are typically found in this, uh, middle buffy coat layer. Uh, and while, um, isolation methods vary based on the company that's used, um, typically the idea is that the upper layers, excluding the red blood cells, are then transferred to another tube, um, and spun down again to create a, uh, platelet-rich cell pellet. Um, and this, uh, particular approach, you typically also get the leukocytes down here to make leukocyte-rich PRP. If you do a slower spin for the first spin, you can, um, kind of separate out the, uh, platelets from the leukocytes to get leukocyte-poor PRP. And I am not going to dive into that today, because that's a whole other lecture that there's definitely not time for, but hopefully subsequent lectures will discuss. So once you have your cell pellet or your, um, what that contains, the, the, the platelets, you can, uh, suspend it as, in as much, basically as much of this platelet-poor plasma as you like, and then inject that, uh, solution into the patient. So how does PRP work? Um, the general answer is we don't know, um, but to try to, you know, kind of take a gander at it, uh, it's likely that it has multiple mechanisms. Um, it is likely an inflammatory mediator, uh, which can decrease the, uh, or basically inhibit the actions of inflammatory molecules such as TNF-alpha or IL-1. Um, it also has immune-modulating properties, um, as we kind of discussed before. There's some suggestion in vitro and possibly in vivo and animals that there's increased extracellular matrix deposition. Um, this is probably a result of the, uh, platelets that contain, uh, bioactive growth factors and proteins that stimulate, uh, the cells, um, the chondrocytes in particular, to release, uh, uh, extracellular matrix molecules to help build the tissue. Uh, there's also probably these, um, these growth factors tend to have positive effects also on the osteoblast and the subchondral bone and potentially as well as the synovial sites. Um, there may also be a, um, component of chemokines contained within the, um, within the solution that can help, uh, recruit MSCs, uh, to the, uh, to the site as well to help, uh, differentiate and form tissue. All right. So what is the FDA's stance on platelet-rich plasma? Uh, blood-derived products such as platelet-rich plasma are not regulated as human cells, tissues, and, uh, cellular and tissue-based products. Um, most devices to isolate PRP are cleared through a 501k pathway, um, which I won't discuss, but I just want to emphasize that it's not PRP, the product itself that is, that is cleared. And PRP is only indicated by the FDA for use mixed with bone autographs or allographs during orthopedic surgeries or to prepare as a gel for treatment of cutaneous wounds. Thus, for those of you, um, who see PRP used in the clinic, it's important to realize that this is all off-use, or, um, off-label use of PRP. So clearly, as we know, PRP is becoming more and more popular, um, and clinically as well as, um, research is, uh, expanding. Um, back in the early, or the mid to late 2000s, there was barely any papers published. Uh, it was initially used in dental surgeries, um, but now you can see that, uh, the amount of, uh, research being published is, is skyrocketing. Um, this is kind of in part due to, um, I don't, I wish I could ask you guys if you knew who this guy is, but since I can't, I'll tell you, this is Hines Ward. He, um, kind of launched PRP into stardom, um, in the 2008 Super Bowl when he tore his, or at least partially tore his MCL, uh, during a playoff game and then was able to return a couple weeks later, um, and the credit was given to PRP for helping him heal so quickly. So PRP is not only used for musculoskeletal conditions such as osteoarthritis or tendon injury, but it's also used for many other conditions off-label. Um, some of you may have heard of vampire facials, which were made famous by Kim Kardashian, where essentially you isolate PRP and then you perform microneedling, injecting small amounts throughout the face in order to help hopefully rejuvenate the skin. PRP is also being investigated, um, for alopecia, um, with, uh, various effects. So the last thing I want to talk about with PRP is kind of the variations and preparation. This is just a selection. This is not an exhaustive, um, list of the different systems that are used to create PRP, but you can see that there's a lot of different, um, basically types of PRP that you get by using these different devices. Um, the spin time can change, the number of spins can change, whether you activate it with a calcium chloride or another substance, um, varies. The amount of blood that you need in order to obtain the PRP is different. The amount of volume that you get is different. Um, so there's a lot of amount of volume that you get is not as quite wide ranging, but can vary. And it can also vary from patient to patient, but the platelet concentration certainly changes a lot as does the, um, the white blood cell content, LP being leukocyte poor and LR being leukocyte rich. And then finally, the hematocrit or the RBC content, um, also varies depending on the way that you isolate the PRP. Um, so a little bit of repetition, but, um, basically I want to emphasize that there are many factors that influence PRP characteristics. Um, they can be patient characteristics such as age, sex, the time of day that's isolated, whether the patient has recently exercised affects the growth factors within PRP, whether or not the patient use, uh, uses NSAIDs or, uh, things like warfarin or aspirin obviously can affect PRP because it affects the platelets, um, the severity of the disease. So it seems that PRP may not be as effective for very severe arthritis, um, as opposed to, uh, more mild arthritis and the general activity level of the patient. Um, you know, do they undergo a physical therapy program following the PRP injection? And as I mentioned before, the preparation also, uh, can vary the effects of PRP. And what this has done is this has created a lot of difficulty in summarizing and establishing exactly how well PRP works and what indications it works for. There's been a lot of call to try to standardize, um, to kind of classify the types of PRP so that it's clear within studies, um, what's being used, but in the end we're really just going to need, uh, some larger studies in order to understand more fully, uh, how PRP actually works and how effective it is. Okay, so now I want to transition, uh, to talking about stem cells or not stem cells. Um, so I just want to remind everybody, as I said before, stem cells are not currently FDA approved for any orthopedic application. And what I'm actually going to talk about is not stem cells, but, um, clinically used products that may contain stem cells. So the first I want to speak about is, uh, bone marrow aspirate concentrate. So what this is, so some people might call it bone marrow stem cells, but you should not call it that. It is bone marrow aspirate concentrate. So the way we obtain this is, is through a, um, a bone marrow biopsy kind of standard as you would for, um, if you're walking around doing bone marrow biopsies in the hospital, usually through the PSIS. Um, you aspirate the bone marrow and then you simply spin it down using a similar system to the PRP. And then you have your bone marrow aspirate concentrate. Um, what's important to realize about this is, as I mentioned, the number of stem cells is quite low. So less than, certainly less than 1% and often less than 0.01% of cells obtained from this, uh, aspiration are actually stem cells. Uh, most of the BMAC devices similar to PRP are FDA cleared through the 510K pathway. Um, whereas, um, the product itself is not FDA approved or clear. BMAC is indicated for autologous use, meaning to return it back into the patient. Um, only you cannot take BMAC from one patient and transfer them to another. Um, you can use it for, uh, concentrating bone marrow for diagnostic use and also similar to PRP, you can mix it with bone allograft or autograft. And that is, these are the only currently cleared indications for bone marrow aspirate concentrate. So anytime we inject it, um, into our patients, it is an off label use and should be described as such. So microfragmented adipose tissue is gaining a popularity. Some people think it's actually more powerful than BMAC. Um, but it's basically obtained from aspiration adipose tissue from either the flank or the abdomen. Uh, the fat, but I mean, it can be obtained from anywhere, but that's typically where we get it because that's usually a location of where there's plenty of fat to be obtained. Um, the fat is then mechanically disassociated, um, by placing it into a tube, which contains, uh, these like five stainless steel balls and you literally shake it. Um, the actual instructions suggest to shake it like a bartender. And then after you, you break up the tissue, you subsequently irrigate it with saline, um, to further separate out the, the fat tissue and the blood. And then you aspirate it through a filter, um, in order to obtain the concentrated fat tissue, um, as well as the cells that go along with it. So for microfragmented adipose tissue, part of the reason that people think that it might be more effective is that a larger quantity of the cells are, um, that are obtained are actually stem cells. Again, the devices are cleared through the 510K pathway and there's no, unlike PRP, which it can, and BMAC, which are approved for, um, for the mixing with allografts or autografts, uh, there's no specific indication, uh, for microfragmented adipose tissue only. They say it's for surgical use. Um, in terms of the mechanism of action of, of BMAC and MFAT, it's not really well understood, but it's likely similar to PRP. Uh, as we discussed before, the stem cell number and the engraftment following injection is quite limited and so it is likely just more the paracrine effects or the direct effects of the growth factors that are obtained within the tissue. And this fact should be carefully explained to patients and these should not be marketed as stem cell products. So what is the bottom line on orthobiologics? I obviously did not go into the research today because I'm hoping that that will be a more in-depth discussion later on in the series, but there is some evidence that they can decrease pain and increase physical function, particularly in mild tissue degeneration. However, more robust clinical studies are clearly needed both in terms of more carefully choosing patients, more carefully acknowledging the differences in preparation methods, as well as increasing the size of the studies. And additionally, I personally, as a basic scientist, I'm quite passionate about trying to further understand the mechanisms through which these products act and I believe that that is essential in order to more effectively move these treatments forward in clinical care. And I just want to remind everybody once again that any injection that we do using orthobiologic products, except for putting hyaluronic acid into a knee joint, is currently an off-label use. And so the primary reason that I feel like it's really important to emphasize the current limitations in our knowledge regarding orthobiologics and their mechanisms is that there's many clinicians out there who are clearly overstating the capabilities of their treatments. So these are just things I pulled from the internet. So there's a clinic that's showing that, you know, this person was clearly in stage OA miraculously after their stem cell treatment has gained some space within their knee. Who knows where this came from? Who knows if it's true? It's not published anywhere. It may just be the difference between a weight-bearing and a non-weight-bearing x-ray. We don't know. But there's currently not significant evidence that these orthobiologics can reverse the progression of osteoarthritis. Additionally, there's a lot of people promoting stem cell therapies, which none of are approved in the United States, and for various conditions, basically any musculoskeletal condition, in addition to IV injections of stem cells for conditions such as COPD, for depression, Lyme disease, and even erectile dysfunction. But none of these are FDA-approved or clinically proven. And then, you know, especially with COVID, I've started hearing about people talking about exosome papers. I can't remember exactly where I pulled this from. It was a while ago. But this is essentially, these are non-MDs. I don't remember what type of clinician they were, but they were selling exosome paper for treatment of COVID. So it's really important that we tell our patients what is, you know, known by fact. And even if you have something that's more of a clinical gestalt or anecdotal evidence that you've seen as a clinician, it's important that you are very straightforward with them and explain that. And, you know, as I mentioned, since none of these therapies are FDA-approved, they cost a lot of money. And they also carry some risk because while the FDA is working on regulating them, it's hard to keep up. So there's a risk of infections with poor sterilization. Actually, you know, there's a recall on some products that are used in our clinics recently. And while, of course, the legit stem cell therapies are advancing, it's hard for them to advance as quickly as the bogus clinics. So in summary, I encourage you all to read a lot, to know the evidence, and to talk, especially if you're a trainee, to talk to your attendings, talk to those who are involved in research in order to develop an appropriate evidence-based practice. You know, these treatments are widely used. Your patients are going to ask you about them. So it's only helpful if you are well-educated. And remember that when you talk to your patients about these, you need to have it, you know, just be very clear with what you is and isn't known about the efficacy and the mechanisms of these treatments and ensure that you're involving the patient in the shared decision-making process. So what's on the horizon? So as I mentioned before, as a basic scientist, I'm hoping that we can kind of take some of what we found in the clinical realm and bring it back to the bench to further understand how these treatments work and how we can make them better in order to provide our patients with better care and hopefully, you know, someday actually get these treatments FDA approved so that we're not charging our patients thousands of dollars out of pocket for these types of treatments. I also want to put in a quick plug for a future lecture that will be given by my primary faculty mentor here at the University of Pittsburgh, Fabrizio Ambrosio, on the promise of regenerative rehabilitation strategies, which is basically the combination of what we think of as, you know, regenerative medicine that I've spoken about today with traditional rehabilitation protocols such as neuromuscular electrical stimulation, therapeutic physical activity like physical therapy, as well as assistive technologies and how these come together to enhance the regenerative medicine, the capabilities of regenerative medicine in order to optimize outcomes. And with that, I'd like to thank everyone for joining. And my contact information was there, both my email and my Twitter, feel free to reach out anytime. And I will take any questions that people have. Thank you so much, Dr. Bean. Again, let's start from the beginning. All right. I'm loving this overview, Dr. Bean. Is there any fraction of researchers looking into hemopoietic stem cells and immune mediated tissue repair from orthopedic injuries? If so, how does this look different from MSC research and application? So I think there is certainly, I've seen research looking at not so hematopoietic stem cells, but how immune cells mediate repair. So for instance, I am interested in extracellular vesicles and how they act on cells. And there's a paper that shows that by activating lymphocytes that you can isolate their extracellular vesicles and actually get enhanced repair of tissues like tendon using these cells or using these extracellular vesicles that are isolated from those cells. So I don't, I'm sure there might be use of hematopoietic stem cells for musculoskeletal conditions, but I've seen it more in the more differentiated cell realm. Thanks. There's been new, some new literature surrounding tendon repair with labs trying growth factor BNP 212 for tendon repairs in the larger context of stem cell injections. Do you think stem cells will find success on their own or will they require the use of adjuncts like growth factors, gene therapy, biomaterials, and scaffolds? I think that, I mean, I think that the early animal data is somewhat limited in its effects. I do think stem cells certainly have potential and I'm kind of all on board with that, but I do think that things, especially like, like scaffolds that helped maintain the cells in place and give them a kind of a fighting chance to maintain their paracrine effects or even to engraft will be important. You know, certainly people have been working on this for, you know, 20 plus years and there hasn't been a huge breakthrough. So I'm hoping that within the next, you know, 15, 20 years, certainly in my career lifetime, that we'll see somehow something that creates this huge jump forward in tissue engineering and results in much more effective treatment with stem cells. But yeah, I agree that, that there may be need to be like a company, like that chart I showed with the bubbles on the outside. Like I think we need to combine different things and perhaps the regenerative rehabilitation is the answer where we can provide mechanical stimulation. And that will be the thing that takes us over the edge. We, we got a comment about how the FDA just started to hand out warning letters to those that are advertising RegenMed procedures. The main points are listed below marking RegenMed medicine and stating that it treats certain disease or conditions, et cetera, et cetera. Yeah. Yeah. I, you know, if you, if you search on the FDA website, you can actually see some of those letters and how they're worded. Most of them focus on saying like, you're purporting this, this is not FDA approved. You cannot say these things. I, I am wondering what's going to happen with like these, the MFAT with the adipose tissue, because they fall in this weird gray area where typically they're you know, they're regulated through the device, but you know, the, the regulation of the FDA to avoid being marketed as a drug requires autologous use, which we do, but it also requires homologous use. And the FDA has described adipose tissue as a structural tissue, and we certainly aren't using it as a structural tissue when we inject it into a joint nerve or a tendon. So I'm wondering if there's going to be a kind of blowback on that in the future. So, but yeah, they're definitely going all out on the amniotic membrane and exosomes right now. Great presentation, Dr. Bean. Is there any research on the combination of different orthobiologics in a way that they can work synergistically and take advantage of their different mechanisms of actions? Thinking about OA, knee OA? Yeah, there actually is a study, and I'll actually send it to you Marcos, but looking at combining those, those two specifically and showing somewhat better outcomes than, than using them alone. The effects are certainly modest and, but I will say that in my off-label use, we have done that clinically with some apparent benefit. But yes, again, I think combining things is the way to go. And the idea is that although it's not well understood, the potential mechanism is that the hyaluronic acid as the gel can act as a kind of scaffold to help keep the PRP in place as it continues to release its factors. Are there any exciting developments that you think are right around the corner? Oh my gosh. That's a tough question. I mean, so I will say, if I want to talk about clinically, one of the things that I am really interested in and that everyone should keep an eye out for, I don't know if there's any Emory people kind of on the line, but is the Miles study. And that is a relatively large well-powered study looking at the common, or looking at a comparison directly of PRP and MFAT, BMAC, as well as I believe umbilical derived stem cells and directly comparing each of these. And I think that that will give us a really good idea of whether it matters which of these we use, especially considering we don't know the mechanism. It's important to know if it, you know, if I can do a relatively cheaper PRP instead of, you know, that I just get from blood versus going into somebody's bone marrow, like I'd much rather do that. So I think in the next, you know, few years that will be really helpful. The next question is, thank you for presenting on this topic, Dr. Bean. I was curious if you've seen research on how allogenic transplants or the biologic source stem cells react in regards to host immune response activation rejection, and if there's any washing out required for this intervention. Yeah, so most of the research has been focused on autologous transplantation. There, I think there's some studies, if you read the literature, I might cancel, I didn't know off the top of my head, but there are studies that show that allogeneic transplants can be safe, likely mostly because there's not that many cells to be had. As I mentioned, like one of the things I'm particularly interested in is looking at extracellular vesicles, which are basically these little tiny nano vesicles that are released by all different cell types, and they contain growth factors, proteins, nucleic acids, as well as lipids. And they may be the thing that's doing most of the signaling that I talked about from the paracrine signaling. And that, those are in particular, since they don't have, they're not cells, they actually don't stimulate the immune system, so they're protected. So perhaps that's the way to go in the future. What are the conclusions about overall clinical efficacy of orthobiologics? I mean, that's a big question. I think it's ongoing, right? We don't really know. I think anecdotally, people have had success, but we don't have a lot of those really rigorous studies. Placebo is mighty, right? There are studies that show that 30% of people just get improvement for arthritis with saline injections. So are these better than that? It's kind of TBD. I do think that with, you know, the meta-analyses that are put together, for something like PRP, as well as I think the adipose and the BMAC, there is some slight benefit. But how long-lasting, we don't know. It seems like, you know, with steroid, if you get three months, hyaluronic acid, you get six months maybe. But perhaps the PRP and the other treatments can last a little longer. But I think there's just so much more work that needs to be done that it's really hard to come to any very strong conclusions at this point. In the areas that are commonly injected with stem cells, do you think these cells have adequate oxygenation, nutrients, and anything else that they might need to grow? Or should we find a way to supply this to the cells? Yeah, so I think that, you know, that's a tough question, right? So as I mentioned before, there's not a lot of engraftment of these cells anyway. We've shown that they don't survive very long. And it may be due to oxygenation. It may just be due to, you know, them just not having kind of a place to land. But certainly, with the way we're approaching things now, the changes that we see are not due to stem cell survival. So definitely, if we want to enhance growth of these stem cells that we're injecting, and to make sure that they are participating in these, in the regeneration, that we will need to find different ways. And, you know, perhaps an easy way to do that is to have them attached to like a scaffold. I just wanted to mention too, I think on a basic science level, it's very difficult. Just, it's all your controls perfect to get the perfect amount of cells that you want. So when you actually do the bench research, you realize it's way more difficult than what it's portraying in the media. It's really difficult to get that select amount that you want. So that's something to keep in mind too, with all these questions. But I think we're about out of time. But any other last minute questions if Dr. Bean wants to say? No. Okay. All right. Thank you so much, Dr. Bean. That was amazing. Yeah, thank you so much. All right. Thank you guys. The next one should be May 4th. That is to be announced, the speaker, but we will be continuing for a year. And it will include basic science researchers, translational researchers, and bioethics researchers as well, which are very important in this discussion. Thank you guys. Have a good night.

orthobiologics

regenerative medicine

clinical applications

evidence-based practice

tissue regeneration

FDA approved

preparation methods

mechanisms of action

effectiveness

risks