If a clinician isolates mesenchymal stem cells from the fat, bone marrow, or muscles of a patient, how can they tell if these cells will be effective? Short answer – they can’t. How well the cells grow in culture and how they look is the best indicator to date, but these indicators can fool you.
Fortunately, the highly productive laboratory of Darwin Prockop from the Institute of Regenerative Medicine at Texas A & M has discovered that the expression of a gene called TSG-6 can act as an indicator for human bone marrow mesenchymal stem cell quality.
In this paper, Prockop and others examined mice that had suffered damage to the surfaces of their eyes (corneas). To mitigate the inflammation in the eye, Prockop and his colleagues applied bone marrow-derived mesenchymal stem cells, but it was clear that the stem cell batches varied remarkably in their ability to regulate inflammation.
Prockop and his group then examined the genes expressed in the different batches of bone marrow-derived mesenchymal stem cells (MSCs) in order to determine if there was a gene that was consistently expressed in the effective batches as opposed to the ineffective batches.
Fortunately, they hit pay dirt. Reverse Transcriptase-PCR assays of human MSCs for the TSG-6 gene accurately predicted their ability of a specific batch of cells to modulate inflammation during corneal injury, or damage to the body wall (sterile peritonitis), or drug-induced injury to the lung. Thus, if you want implanted MSCs to modulate inflammation, then you want cells that express TSG-6 at a high level.
However, if you want MSCs that make bone, then you do not want cells that express high levels of TSG-6 because the levels of TSG-6 mRNA were negatively correlated with their potential for osteogenic (bone cell) differentiation in culture.
Additionally, when donated MSCs from male and female donors were examined and compared, it was clear that MSCs from female donors more effectively suppressed sterile inflammation, expressed higher levels of TSG-6, and had slightly less osteogenic potential than those from male donors.
Thus, TSG-6 is a marker that can measure the ability of a batch of MSCs to suppress inflammation. It is unclear if this same gene marker equally applies to other types of MSCs, but that will hopefully become clear with further work. Also, markers that correlate with the ability of these cells to do other types of regenerative activities might also result from experiments like these.
The regenerative medicine company Regeneus Ltd announced this week that the Australian Football League or AFL has decided to approve, on a case-by-case basis, the use of its innovative HiQCell stem cell therapy as an optional treatment for injured AFL players. Football (soccer) players tend to suffer from impact-related osteoarthritis and tendonitis.
Regeneus’ Commercial Development Director for Human Health, Steve Barbera, said, “It’s pleasing that HiQCell has been approved under the new AFL Prohibited Treatments List released in March 2014. HiQCell also received clearance as an approved therapy from the Australian Sports Anti-Doping Authority (ASADA) for use with athletes who participate in sporting competitions subject to the WADA Anti-Doping Code, including the AFL. This recent decision by the AFL demonstrates a further level of compliance, specifically for players within that sporting code.”
Regeneus’ HiQCell treatment is the only stem cell treatment for osteoarthritis that has been subjected to the highest level of clinical scrutiny. A double-blind placebo-controlled safety trial is the gold standard for clinical trials. The particular clinical trial to which HiQCell treatments were subjected showed that HiQCell is safe and it reduces pain and halts cartilage degradation in arthritic joints. Additionally, the ongoing effects of HiQCell are being tracked in over 380 patients in an independent ethics-approved registry. A recent registry update demonstrated that patients are maintaining significant improvements 2 years after their treatment.
HiQCell has already been used to treat several high-profile athletes across several sporting codes, including the National Rugby League, which was announced on May 7th, 2014. It is encouraging for Regeneus that elite sports patients can use their HiQ therapy to much quickly return to sports from hard-to-treat injuries and continue their playing careers after receiving this innovative therapy.
Dr Phil Bloom, a Melbourne based Specialist Sports and Exercise Physician and HiQCell treating medical practitioner, said, “permission from the AFL for HiQCell treatment is a positive progression as it allows for an additional option for players with conditions that are unresponsive to existing treatments”.
The HiQCell treatment uses stem cells harvested from a small amount of a patient’s fat. After separating and concentrating these regenerative cells, they are re-injected in osteoarthritic-affected joints such as knees, hips and ankles. The HiQCell treatment reduces inflammation and repairs damaged tissue when it is carried out under the supervision of a medical practitioner.
Mesoblast Ltd has announced the results of their clinical trial in type 2 diabetics at the annual meeting of the American Diabetes Association.
Mesoblast has developed a proprietary adult stem cell they call a mesenchymal precursor cell or MPC, which they are attempting show can be used as an “off the shelf” medical product. MPCs seem to act like immature mesenchymal stem cells that can modulate the immune response and have greater flexibility.
In this trial, Mesoblast was banking of the ability of administered MPCs to suppress inflammation. Type 2 diabetes results from an insensitivity of tissues to secreted insulin. Consequently, cells do not receive enough of the insulin signal to take up sugar and make protein, glycogen, and fat. Another prominent feature of type 2 diabetes is chronic, low-level inflammation, which is largely due to the chronically high blood glucose concentrations that damages cells, blood vessels, nerves, and connective tissue. By treating type 2 diabetics with MPCs, Mesoblast was hoping to ascertain the ability of MPCs to quell chronic inflammation.
The trial was conducted across 18 sites in the US. 61 patients with type 2 diabetes received either one intravenous infusion of 0.3, 1.0 or 2.0 millions MPCs per kilogram body weight over 12 weeks. One group of patients were given a placebo. Patients had suffered from diabetes an average of 10 years and had poor control with the drug metformin (Glucophage), which is one of the most widely-used drugs for type 2 diabetes.
The results were largely positive:
When it comes to safety, there were no safety issues observed during the 12-week study period. The MPC cell infusions were well tolerated (with a maximal dose of 246 million cells). With regard to efficacy, there were dose-dependent improvement in glycemic control as evidenced by a decrease at all time points after week 1 in hemoglobin A1c (HbA1c) in MPC- treated patients compared with an increase in HbA1c in placebo treated subjects. HbA1c is a blood test that determines how much damage the high sugar levels are doing to the body. The test uses the blood protein hemoglobin to assess the damage that high glucose levels are doing to the rest of the body. In this clinical trial, significant reductions in HbA1c were observed after 8 weeks in the 2 M/kg MPC group compared to placebo (p<0.05) which was sustained through 12 weeks. The reduction in HbA1c was most pronounced in subjects with baseline HbA1c ≥ 8% (i.e. those patients with relatively poorer glucose control).
Fasting insulin levels were reduced in the 1 million and 2 million/kg groups compared to placebo (P<0.05), and reduced levels of inflammatory cytokines TNF-alpha and IL-6 (which are made at high levels during inflammation) were observed at 12 weeks in MPC groups compared to placebo.
The scientists and physicians involved in this clinical trial concluded there was sufficient evidence to support further evaluation into the use of MPCs in the treatment of type 2 diabetes and its complications. They also thought that there were grounds for exploring other therapeutic venues in which MPCs might prove useful.
Mesoblast Chief Executive Silviu Itescu said: “We are very pleased with these results which are consistent with an immunomodulatory mechanism by which our MPCs may have glucose-lowering effects in patients with type 2 diabetes. We are evaluating whether similar effects may be seen with the use of MPCs in the treatment of kidney disease and other complications of type 2 diabetes.”
While it is improbable in the extreme that this one-time treatment will improve the long-term clinical outcomes of diabetics, it is possible that repeated treatments will provide better Glycemic control for poorly controlled diabetics, and that these repeated treatments will produce long-term improvements in the health of these patients.
Chinese physicians and stem cell researchers from Shenzhen, China have reported on their clinical trial that treated 40 patients with severe and refractory lupus systemic erythematosus with mesenchymal stem cells isolated from umbilical cord. This 40-patient, multicenter study targeted patients with active and difficult-to-treat lupus.
Systemic lupus erythematosus (SLE), which is also simply known as lupus, is an autoimmune disease in which the body’s immune system mistakenly attacks healthy tissue. Lupus can affect the skin, joints, kidneys, brain, or even other organs.
What causes lupus is uncertain, but tissue damage seems to predispose some people to the onset of lupus. Lupus commonly affects women than men, and it can occur at any age. It most commonly appears most often in people between the ages of 10 and 50, and African-Americans and Asians are affected more often than people from other ethnic groups. Particular drugs have also been linked to the onset of lupus or lupus-like conditions (e.g., isoniazid, hydralazine, procainamide, and less commonly anti-seizure medicines, capoten, chlorpromazine, etanercept, infliximab, methyldopa, minocycline, penacillamine, quinidine, and sulfasalazine).
The symptoms of lupus vary tremendously and they usually come and go. Almost all lupus patients have some joint pain and swelling, and some develop arthritis. Typically the joints of the fingers, hands, wrists, and knees are most often affected. Other symptoms include chest pain when taking a deep breath, fatigue, fever, general discomfort, uneasiness, or ill feeling (malaise), hair loss, mouth sores, swollen lymph nodes, and sensitivity to sunlight. Also, a specific type of skin rash known as a “butterfly” rash occurs in about half of lupus patients. The butterfly rash is most often seen over the cheeks and bridge of the nose, but can be widespread and gets worse in sunlight. Some people have only skin symptoms and have what is known as discoid lupus.
Chronic lupus usually becomes concentrated in specific organs, which can cause secondary symptoms. These symptoms can include:
Thus more efficacious and safe ways to treat recalcitrant cases of lupus have included stem cell treatments. In particular, mesenchymal stem cells and their ability to suppress inflammation. To that end, several pre-clinical and clinical trials have tested mesenchymal stem cells from bone marrow, fat and umbilical cord to reduce the chronic inflammation associated with particular autoimmune diseases (see P Connick, et al., Lancet Neurol. 2012 Feb;11(2):150-6; MM Bonab, et al., Curr Stem Cell Res Ther. 2012 Nov;7(6):407-14; J Voswinkel, et al., Immunol Res. 2013 Jul;56(2-3):241-8; P Connick P, et al., Trials. 2011 Mar 2;12:62; D Karussis, et al., Arch Neurol. 2010 Oct;67(10):1187-94; B Yamout, et al., J Neuroimmunol. 2010 Oct 8;227(1-2):185-9).
This new Chinese trial provides some very interesting and welcome data on the use of mesenchymal stem cells from umbilical cord to treat lupus.
Dr. Xiang Hu, who founded the biotechnology company Beike, said, “We are pleased with the results we have seen in our clinical trial. While some severe cases experienced relapse after 6 months, the results show a markedly improved quality of life expectation. This is a big step forward in combating autoimmune disease. We will now be looking to further our SLE research efforts to find even better results.”
The forty patients who participated in the study were recruited from four centers in China. The umbilical cord-derived mesenchymal stem cells used in the study were processed by Beike Biotech’s scientists at the company’s new state-of-the-art Jiangsu Stem Cell Regenerative Medicine Facility in Taizhou, China. Stem cells from sources other than the patient’s own body are known as allogeneic stem cells, and these forty patients, all of whom have refractory lupus were infused with umbilical cord mesenchymal stem cells intravenously at the beginning of the study and one week later. To score each patient’s disease progression, a clinical test called a SLEDAI or Systemic Lupus Erythematosus Disease Activity score. The SLEDAI score results from a compilation of multiple clinical and laboratory tests.
After 6 months, all patients showed significant improvement in their SLEDAI scores, but after six months, several patients experienced relapse, which required a repeat treatment with mesenchymal stem cells. Also, the safety profile of these cells was superior to many of the drugs used to treat lupus.
This study is suggests that the mesenchymal stem cells suppress active lupus without causing severe adverse effects. However, in order to show that definitively, a double-blinded, placebo-controlled study must be conducted. Also, trying to provide longer periods of relief rather than just six months of relief is another factor that further work will hopefully address.
A study at the Texas Health Science Center has shown that stem cell treatments that quash inflammation soon after traumatic brain injury (TBI) might also offer lasting cognitive gains.
TBI sometimes causes severe brain damage, and it can also lead to recurrent inflammation of the brain. This ongoing inflammation can extend the damage to the brain. Only a few drugs help (anti-inflammatory drugs for example). Up to half of patients with serious TBI need surgery, but some stem cells like a sub group of mesenchymal stem cells called multipotent adult progenitor cells (MAPCs) can reduce short-term inflammation, and induce functional improvement in mice with TBI. Unfortunately, few groups have gauged the long-term effects of MAPCs on TBI.
In an article that appeared in the journal Stem Cells Translational Medicine, a research team led by the Director of the Children’s Program in Regenerative Medicine, Charles Cox, reported the use of human MAPCs in mice that had suffered TBI.
In this study, Cox and his colleagues infused MAPCs into the bloodstream of two groups of mice 2, and 24 hours after suffering a TBI. The first group of mice received two million cells per kilogram, and mice in the other group received an MAPC dose five times stronger.
Four months after MAPC administration, those mice that had received the stronger dose continued to experience less brain inflammation and better cognition. Spatial learning was increased and motor deficits had decreased.
According to Cox, the intravenously administered MAPCs did not cross the blood/brain barrier. Since immune cells can cross the blood/brain barrier for a short period of time after a TBI and cause autoimmunity, this result shows that the MAPCs are quelling inflammation through “paracrine” mechanisms (paracrine means that molecules are secreted by the cells and these secreted molecules elicit various responses from nearby cells). Cox made this clear: “We spent 18 months looking for them in the brain. There was little to no engraftment there.”
Rather than entering the brain, the MAPCs “set up shop in the spleen, a giant reservoir of T and B cells. The MAPCs change the spleen’s output to anti-inflammatory cells and cytokines, which communicate with immune cells in the brain—microglia—and change their response to injury from hyper-to-anti- inflammatory. The cells alter the innate immune response to injury. We have shown this in a sequence of papers.”
University of Cambridge neurologist, Stefano Pluchino, has worked with immune regulatory stem cells. Pluchino said that Cox’s study shows a “good dose response” on disability and behavior “after hyperacute, or acute, intravenous injection of MAPCs.” However, Pluchino noted that the description of the effects of MAPCs on microglia (white blood cells in the brain that gobble up foreign matter and cell debris) is “speculative.” Pluchino continued: “It is not clear whether these counts have been done on the injured brain hemisphere, and whether MAPC effects were observable on the unaffected hemisphere. The distribution and half-life of these MAPCs is not clear” and has never been demonstrated convincingly in Athersys papers (side note: Athersys is the company that isolates and grows the human MAPCs). “It is also not clear if effects in the Cox study were a ‘false positive,’ secondary to a paradoxical immune suppression the xenograft modulates.” That is, a false positive could occur because human cells in animal bodies rouse immune reactions. “It is not clear where in the body these MAPCs would work, either out or into the injured brain.” Additionally the mechanism by which these cells act does not seem to be clear, according to Pluchino.
But, Pluchino added: “Athersys is already in clinic with MAPCs in graft vs. host disease, myocardial infarction, stroke, progressing towards a phase I/II clinical trial in multiple sclerosis, and completing the pre-clinical work in traumatic brain and spinal cord injuries. Everything looks great. The company is solid. The data is convincing in terms of behavioral and pathological analyses. But the points I have raised are far from clarified.”
Cox admitted that Pluchino’s points are valid. He pointed out that human cells were used in rodents, since the FDA wants pre-clinical studies in laboratory animals in order to first evaluate the safety and efficacy of the exact cells to be used in a proposed therapy before they head to the clinic. “As we are not seeking engraftment of these cells, and would not plan to immunosuppress a trauma patient, we have not pursued animal models that use immunosuppression. Our study was designed with translationally relevant end-points, recognizing the limitations of not having a final mechanism of action determined. The growing consensus is there are many mechanism(s) of action in cell therapies.”
Cox also agreed that the suggested effects of MAPCs on microglia, “is not truly a proof of mechanism.” However, Cox and his co-workers have developed a protocol that can potentially more accurately quantify microglia in mice. “We ultimately plan more mechanistic studies to define endogenous microglia versus infiltrating microglia and the effects of various cell therapies. “
Additionally, Cox also said that: “We have published work showing the majority of acutely infused MSCs and MAPCs are lodged in the lung after intravenous delivery. This was an acute study in non-injured animals, but others have shown similar data.” In another study, Cox’s research group showed that the cells cluster in the spleen, which corroborates work by other research groups that have used umbilical cord cells to treat stroke.
Finally, Cox disagrees that the suppression of immune cell function in animals by human cells is appropriately characterized as “a false positive.” Cox explained that the infused cells induce a “modulation of the innate immune response, and typically, the immune rejection of a transplant is associated with immune activation, not suppression. So it well may be a ‘true positive.’”
In order for MAPCs to make to the clinical trial stage, Cox will need to investigate the mechanisms by which MAPCs suppress inflammation and if their purported effects on microglia in the central nervous system are real. He will also need to show that these cells work in other types of laboratory animals beside mice. Rats will probably be next, and after that, my guess is that the FDA would allow Athersys to apply for a New Drug Application.
Research led by Charles Cox at the University of Texas Health Science Center has shown that stem cell therapy given during the critical time window after traumatic brain injury promotes lasting cognitive improvement. These experiments, which were published in the latest issue of the journal Stem Cells Translational Medicine, provide a pre-clinical model for experiments with larger animals.
After the brain has suffered a traumatic injury, there are few treatment options. Damage to the brain can be severe, and can also cause ongoing neurological impairment. Approximately half of all patients with severe head injuries need surgery to remove or repair ruptured blood vessels or bruised brain tissue.
In this work from Cox’s lab, stem cells from bone marrow known as multipotent adult progenitor cells (MAPCs) were used. MAPCs seem to be a subpopulation of mesenchymal stem cells, and they have a documented ability to reduce inflammation in mice immediately after traumatic brain injury. Unfortunately, no one has measured the ability of MAPCs to improve the condition of the brain over time.
Cox, Distinguished Professor of Pediatric Surgery at the UTHealth Medical School and in collaboration with the Children’s Fund, Inc., injected two groups of brain-injured mice with MAPCs two hours after injury and then once again 24 hours later. One group received a dose of 2 million cells per kilogram and the other a dose five times greater.
After four months, those mice that had received the stronger dose not only continued to have less inflammation, but they also showed significant gains in cognitive function. Laboratory examination of the brains of these rodents confirmed that those that had received the higher dose of MAPCs had better brain function than those that had received the lower dose.
According to Cox, “Based on our data, we saw improved spatial learning, improved motor deficits and fewer active antibodies in the mice that were given the stronger concentration of MAPCs.” Cox also indicated that this study indicates that intravenous injection of MAPCs might very well become a viable treatment for people with traumatic brain injury in the future.
Cox, who directs the Pediatric Surgical Translational Laboratories and Pediatric Program in Regenerative Medicine at UTHealth, is a leader in the field of autologous and blood cord stem cells for traumatic brain injury in children and adults. Results from a phase 1 study were published in a March 2011 issue of Neurosurgery, the journal of the Congress of Neurological Surgeons. Cox also directs the Pediatric Trauma Program at Children’s Memorial Hermann Hospital.