Positive Results from Mesoblast’s Phase 2 Trial of Cell Therapy in Diabetic Kidney Disease


Mesoblast Limited has announced results from its Phase 2 clinical Trial that evaluated their Mesenchymal Precursor Cell (MPC) product, known as MPC-300-IV, in patients who suffer from diabetic kidney disease. In short, their cell product was shown to be both safe and effective. The results of their trial were published in the peer-reviewed journal EBioMedicine.  Researchers from the University of Melbourne, Epworth Medical Centre and Monash Medical Centre in Australia participated in this study.

The paper describes a randomized, placebo-controlled, and dose-escalation study that administered to patients with type 2 diabetic nephropathy either a single intravenous infusion of MPC-300-IV or a placebo.

All patients suffered from moderate to severe renal impairment (stage 3b-4 chronic kidney disease for those who are interested).  All patients were taking standard pharmacological agents that are typically prescribed to patients with diabetic nephropathy.  Such drugs include angiotensin-converting enzyme inhibitors (e.g., lisinopril, captopril, ramipril, enalapril, fosinopril, ect.) or angiotensin II receptor blockers (e.g., irbesartan, telmisartan, losartan, valsartan, candesartan, etc.).  A total of 30 patients were randomized to receive either a single infusion of 150 million MPCs, or 300 million MPCs, or saline control in addition to maximal therapy.

Since this was a phase 2 clinical trial, the objectives of the study were to evaluate the safety of this treatment and to examine the efficacy of MPC-300-IV treatment on renal function.  For kidney function, a physiological parameter called the “glomerular filtration rate” or GFR is a crucial indicator of kidney health.  The GFR essentially indicates how well the individual functional units within the kidney, known as “nephrons,” are working.  The GFR indicates how well the blood is filtered by the kidneys, which is one way to measure remaining kidney function.  The decline or change in glomerular filtration rate (GFR) is thought to be an adequate indicator of kidney function, according to the 2012 joint workshop held by the United States Food and Drug Administration and the National Kidney Foundation.

nephronanatomy

Diabetic nephropathy is an important disease for global health, since it is the single leading cause of end-stage kidney disease.  Diabetic nephropathy accounts for almost half of all end-stage kidney disease cases in the United States and over 40% of new patients entering dialysis treatment.  For example, there are almost 2 million cases of moderate to severe diabetic nephropathy in 2013.

Diabetic nephropathy can even occur in patients whose diabetes is well controlled – those patients who manage to keep their blood glucose levels at a reasonable level.  In the case of diabetic nephropathy, chronic infiltration of the kidneys by inflammatory monocytes that secrete pro-inflammatory cytokines causes endothelial dysfunction and fibrosis in the kidney.

Staging of chronic kidney disease (CKD) is based on GFR levels.  GFR decline typically defines the progression to kidney failure (for example, stage 5, GFR<15ml/min/1.73m2).  The current standard of care (renin-angiotensin system inhibition with angiotensin converting enzyme inhibitors or angiotensin II receptor blockers) only delays the progression to kidney failure by 16-25%, which leaves a large residual risk for end-stage kidney disease.  For patients with end-stage kidney disease, the only treatment option is renal replacement (dialysis or kidney transplantation), which incurs high medical costs and substantial disruptions to a normal lifestyle.  Due to a severe shortage of kidneys, in 2012 approximately 92,000 persons in the United States died while on the transplant list.  For those on dialysis, the mortality rate is high with an approximately 40% fatality rate within two years.

The main results of this clinical trial were that the safety profile for MPC-300-IV treatment was similar to placebo.  There were no treatment-related adverse events.  Secondly, patients who received a single MPC infusion at either dose had improved renal function compared to placebo, as defined by preservation or improvement in GFR 12 weeks after treatment.  Third, the rate of decline in estimated GFR at 12 weeks was significantly reduced in those patients who received a single dose of 150 million MPCs relative to the placebo group (p=0.05).  Finally, there was a trend toward more pronounced treatment effects relative to placebo in a pre-specified subgroup of patients whose GFRs were lower than 30 ml/min/1.73m2 at baseline (p=0.07).  In other words, the worse the patients were at the start of the trial, the better they responded to the treatment.

The lead author of this publication, Dr David Packham, Associate Professor in the Department of Medicine at the University of Melbourne and Director of the Melbourne Renal Research Group, said: “The efficacy signal observed with respect to preservation or improvement in GFR is exciting, especially given that this trial was not powered to show statistical significance. Patients receiving a single infusion of MPC-300-IV showed no evidence of developing an immune response to the administered cells, suggesting that repeat administration is feasible and may in the longer term be able to halt or even reverse progressive chronic kidney disease. I hope that this very promising investigational therapy will be advanced to rigorous Phase 3 clinical trials to test this hypothesis as soon as possible.”

Patients who received s single IV infusion of MPC-300-IV cells showed no evidence of developing an immune response to the administered cells.  This suggests that repeated administration of MPCs is feasible and might even have the ability to halt, or even reverse progressive chronic kidney disease.

Packham and his colleagues hope that this cell-based therapy can be advanced to a rigorous Phase 3 clinical trial to further test this treatment.

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Stem Cell-Derived Smooth Muscle Cells Help Restructure Urethral Sphincter Muscles in Rats


Stress urinary incontinence affects 25%-50% of the female population and is defined as the leakage of the bladder upon exertion. The exertions that can cause the bladder to leak can be as simple as laughing, coughing, sneezing, hiccups, yelling, or even jumping up and down. Stress urinary incontinence costs Americans some $12 billion a year and also causes a good deal of embarrassment and compromises quality of life. Unsurprisingly, stress urinary incontinence also is associated with an increased incidence of anxiety, stress, and depression.

In most cases of stress urinary incontinence, injury to the internal sphincter muscles of the urethra or to the nerves that innervate these muscles (both smooth and voluntary muscles) significantly contribute to the condition. Conservative management of stress urinary incontinence can work at first, but can fail later on. The other option is corrective surgery that reconstructs the urethral sphincter and increases urethral support. However, even though such surgeries can and often do work, recurrence of the incontinence is rather common. Is there a better way?

Yan Wen from Stanford University School of Medicine and colleagues and collaborators from College of Medicine of Case Western Reserve in Cleveland, Ohio, Southern Medical University in Guangzhou, China, and Montana State University have used a novel stem cell-based technique to treat laboratory Rowett nude rats that had a surgically-induced form of stress urinary incontinence. While the results are not overwhelming, they suggest that a stem cell-based approach might be a step in the right direction.

Wen and others used a human embryonic stem cell line called H9 and two different types of induced pluripotent stem cell lines to make, in culture, human smooth muscle progenitor cells (pSMCs). Fortunately, protocols for differentiating pluripotent stem cells into smooth muscle cells is well worked out and rather well understood. These pSMCs were also tagged with a firefly luciferase gene that allowed visualization of the cells after implantation.

Six groups of rats were treated in various ways. The first group had stress urinary incontinence and were only treated with saline solutions. The second group of animals also had stress urinary incontinence and were treated with cultured human pSMCs that were derived from human bladders. The third group of animals also had stress urinary incontinence and were treated with pSMCs made from H9 human embryonic stem cells. The next two groups also had stress urinary incontinence and were treated with two different induced pluripotent stem cell lines; one of which was induced with a retroviral vector and the second of which was made with episomal DNA. Both lines were originally derived from dermal fibroblasts. The final group of rats did not have stress urinary incontinence and were used as a control group.

The cells were introduced into the mice by means of injections into the urethra under anesthesia. Two million cells were introduced in each case, three weeks after the induction of stress urinary incontinence. All animals were examined five weeks after the cells were injected into the animals.

Because the cells were tagged with firefly luciferase, the animals could be given an injection of luciferin, which is the substrate for luciferase. Luciferase catalyzes a reaction with luciferin, and the cells glow. This glow is easily detected by means of a machine called the Xenogen Imaging System. Such experiments showed that the injected cells did not survive terribly well, and by 9 days after the injections, they were usually not detectable. Two rats that had been injected with retrovirally-induced induced pluripotent stem cell-derived pSMCs lasted until 35 days after injection, but these rats were the exception and not the rule.

Did the cells integrate into the urethral sphincter by the signal is too low to be detected using luciferase? The answer to this question was certainly yes, but the amount of integration was nothing to write home about. Small patches of cells showed up in the urethra sphincters that expressed human gene products, and therefore, had to be derived from the injected cells.

In vivo survival of transplanted pSMCs in RNU rats. (A): The RV-iPSC pSMCs were periurethrally injected into the rats and monitored with BLI. (B): At day 12, a small number of the transplanted cells were detected in the proximal rat urethra. The transplanted human cells were determined by positive staining of HuNuclei and smoothelin. (C): Gene expression of human ERV-3 in rat urethras 5 weeks after cell transplantation. Y-axis on left shows the scale for ERV-3 copy numbers from tissue samples. Each human cell contains one copy of ERV-3 transcript; hence, the number of copies is equal to the number of cells. Y-axis on right shows the ERV-3 copy numbers of the standard cell samples. The cell numbers in the standard graph are 0.5 × 103, 1 × 103, 2 × 103, 4 × 103, 8 × 103, and 10 × 103 (red dots). ERV-3 amplifications in all pSMC-treated groups were very low. Abbreviations: BLI, bioluminescent imaging; bSMC, bladder smooth muscle cell; DAPI, 4′,6-diamidino-2-phenylindole; Epi, episomal plasmid; ERV-3, endogenous retrovirus group 3; H&E, hematoxylin and eosin; Hu, human; HuNuclei, human nuclei; iPSC, induced pluripotent stem cell; pSMCs, smooth muscle progenitor cells; RNU, Rowett Nude; RV, retrovirus vector.
In vivo survival of transplanted pSMCs in RNU rats. (A): The RV-iPSC pSMCs were periurethrally injected into the rats and monitored with BLI. (B): At day 12, a small number of the transplanted cells were detected in the proximal rat urethra. The transplanted human cells were determined by positive staining of HuNuclei and smoothelin. (C): Gene expression of human ERV-3 in rat urethras 5 weeks after cell transplantation. Y-axis on left shows the scale for ERV-3 copy numbers from tissue samples. Each human cell contains one copy of ERV-3 transcript; hence, the number of copies is equal to the number of cells. Y-axis on right shows the ERV-3 copy numbers of the standard cell samples. The cell numbers in the standard graph are 0.5 × 103, 1 × 103, 2 × 103, 4 × 103, 8 × 103, and 10 × 103 (red dots). ERV-3 amplifications in all pSMC-treated groups were very low. Abbreviations: BLI, bioluminescent imaging; bSMC, bladder smooth muscle cell; DAPI, 4′,6-diamidino-2-phenylindole; Epi, episomal plasmid; ERV-3, endogenous retrovirus group 3; H&E, hematoxylin and eosin; Hu, human; HuNuclei, human nuclei; iPSC, induced pluripotent stem cell; pSMCs, smooth muscle progenitor cells; RNU, Rowett Nude; RV, retrovirus vector.

The exciting part about these results, however, was that when Wen and others examined the rat urethral sphincters for the presence of things like elastin and other proteins that make for a healthy urethral sphincter, there was a good deal of elastin, but it was not human elastin but rat elastin. Therefore, this elastin synthesis was INDUCED by the implanted cells even though it was not made by the implanted cells. Instead, the implanted cells seemed to signal to the native cells to beef up their own production of sphincter-specific gene products, which made from a better sphincter. This was not the case in animals that received injections of human pSMCs derived from human bladders.

Assessment of elastin fibers in the proximal urethra of the rat. (A): Representative images of cross-section of proximal urethra with Weigert’s Resorcin-Fuchsin’s elastin and van Gieson’s collagen staining. Elastic fiber shown as dark blue, collagen as red pink, and other tissue elements as yellow. Scale bars = 100 µm. (B): Quantification of elastin fibers was assessed using Image-Pro Plus software and expressed as a percentage of the arbitrary ROIs. Each bar represents the mean value ± SEM. Abbreviations: bSMC, human bladder smooth muscle cells; H9-pSMC, surgery plus H9-pSMC injection; Hu-bSMC, surgery plus injection of human bladder smooth muscle cells; pSMCs, smooth muscle progenitor cells; Pure control, no surgery and no treatment; ROIs, regions of interest; Sham saline, surgery plus saline injection.
Assessment of elastin fibers in the proximal urethra of the rat. (A): Representative images of cross-section of proximal urethra with Weigert’s Resorcin-Fuchsin’s elastin and van Gieson’s collagen staining. Elastic fiber shown as dark blue, collagen as red pink, and other tissue elements as yellow. Scale bars = 100 µm. (B): Quantification of elastin fibers was assessed using Image-Pro Plus software and expressed as a percentage of the arbitrary ROIs. Each bar represents the mean value ± SEM. Abbreviations: bSMC, human bladder smooth muscle cells; H9-pSMC, surgery plus H9-pSMC injection; Hu-bSMC, surgery plus injection of human bladder smooth muscle cells; pSMCs, smooth muscle progenitor cells; Pure control, no surgery and no treatment; ROIs, regions of interest; Sham saline, surgery plus saline injection.

Because these mice were sacrificed five weeks after the injections, Wen and others could not assess the urethral function of these animals. Therefore, it is uncertain if the improved tissue architecture of the urethral sphincter properly translated into improved function even though it is reasonable to assume that it would. Having said that, it is possible that the experiments that detected the presence of increased amounts of elastin and collagen in the sphincters of these rats was complicated by the presence of bladder tissue in the preparations. Since bladder tissue was included in all trials of this experiment, it is unlikely that bladder tissue is the sole cause of increase elastin and collagen in the stem cell-treated rats. Secondly, rat regenerative properties may not properly match the regenerative properties in older human patients. Here again, unless such an experiment is attempted in larger animal models and then in human patients, we will never know if this procedure is viable for regenerative treatments in the future.

For now, it is an interesting observation, and perhaps a promising start to might someday become a viable regenerative treatment for human patients.

This paper appeared in Stem Cells Translational Medicine, vol 5, number 12, December 2016, pp. 1719-1729.

USC Researchers Isolate Human Nephon Progenitor Cells – Future Possibilities for Kidney Regeneration


Researchers at the Saban Research Institute of Children’s Hospital of Los Angeles and the University of Southern California (USC) have reported the isolation of human nephron progenitor (NP) cells. These results, which were published in the journal Stem Cell Translational Medicine, might very well elucidate how progenitor cells differentiate into become renal cells and then develop into kidneys. Such insights could, possibly provide new strategies to promote renal regeneration after chronic kidney failure or acute kidney injury.

Kidneys are composed of about a million tiny filtration units known as “nephrons.” These diminutive structures filter waste and concentrate those wastes into urine, which is leaked into the bladder. In humans, approximately 500,000 to 1,000,000 nephrons are generated before week 34 – 36 of fetal gestation. However, at this point in development, the NP cells are exhausted and kidney development (known as “nephrogenesis”) effectively ceases. If the kidney loses a large enough quantity of nephrons after this time period, such losses may lead to irreversible kidney failure, since no further cell repair or regeneration is possible.

kidney_nephron_civyrose

In past studies, NPs were made from induced pluripotent stem cells, or by utilizing animal models. Scientists at USC and Children’s Hospital of Los Angeles (CHLA), chose a different tactic; they designed an efficient protocol by which they could directly isolate human NPs. To accomplish this, Dr. Laura Perin and her colleagues used RNA-labeling probes to obtain cells that expressed the SIX2 and CITED1 genes. Cells expressing both of these genes are almost certainly NPs, since SIX2 and CITED1 are master regulatory genes that promote renal development.

Dr. Perin, co-director of CHLA’s GOFARR Laboratory for Organ Regenerative Research and Cell Therapeutics in Urology, added, “In addition to defining the genetic profile of human NP, this system will facilitate studies of human kidney development, providing a novel tool for renal regeneration and bioengineering purposes.”

On a rather sanguine note, Perin noted that these experiments, which constitute proof-of-concept work, may create new applications to researchers who might be able to use her laboratory’s techniques to isolated progenitor cells for other organs, the pancreas, heart, or lung. “This technique provides a ‘how to’ of human tissue during development,” said Perin.

“It is an important tool that will allow scientists to study cell renewal and differentiation in human cells, perhaps offering clues to how to regulate such development,” added first author of this paper, Stefano Da Sacco.

Scientists Reprogram Adult Skin Cells to Make Mini Kidneys


Japanese and Australian researchers have used induced pluripotent stem cell (iPSC) technology to reprogram human skin cells to make the most mature human kidneys yet to be grown in a culture. These mini kidneys have hundreds of filtering units (nephrons) and blood vessels and appear to be developing just as kidneys would in an embryo.

“The short-term goal is to actually use this method to make little replicas of the developing kidney and use that to test whether drugs are toxic to the kidney,” said lead researcher Professor Melissa Little, of the Murdoch Children’s Research Institute. “Ultimately we hope we might be able to scale this up so we can … maybe bioengineer an entire organ.”

In other previous research, Professor Little and her co-workers generated cells that self-organized into the nephrons and collecting ducts needed for the kidney to filter blood and produce urine. They used a precise combination of called growth factors to direct embryonic stem cells to develop into the different cell types.

In the journal Nature, Professor Little and her collaborators report they have made a developing kidney from a type of skin cell called a fibroblast. Little and her team reprogrammed adult fibroblasts to become “induced pluripotent stem cells,” which act like embryonic stem cells, and can become any cell in the body. By adopting their growth factor recipe, Little and others were able to grow these cells into larger and more complex, three-dimensional kidneys than previously made.

“These kidneys have something like 10 or 12 different cell types in them … all from the one starting stem cell,” said Professor Little. “What we had previously were little flat structures over the surface of a dish … Now we have an organoid that is about 5-6 millimetres across, has about 100 filtering units in it, and is starting to form blood vessels. It’s starting to mature and the cell types are starting to do more of the functions of the final kidney.”

Scientists in Little’s laboratory demonstrated that the genes expressed in the mini kidneys as they formed faithfully recapitulated the expression of those same genes in a developing kidney in a first trimester embryo.

“It is actually mirroring what is happening in human development,” said Professor Little.

Little and her group also found that the laboratory-grown kidney was damaged when it was treated with known renal toxins. Little suggested that the iPSCs cells they had created were functioning as a kidney, but further tests would be required to demonstrate that.

It might be possible to use these bioengineered kidneys to test the renal toxicity of drugs. Likewise, the production of mini kidneys using cells from kidney patients might provide a way to study inherited forms of kidney disease.

“You can take a fibroblast [from someone with inherited kidney disease], make a stem cell out of it, generate a little kidney and use that as our model for their disease,” said Professor Little.

Perhaps most exciting, laboratory-generated kidneys might one day provide rejection-free transplants for patients, and gene editing could be used to fix the genetic defect that caused an inherited kidney disease.

Professor Jamie Davies of the University of Edinburgh, who was not involved with this work, but commented on it for Nature, emphasized this was not a full-fledged, functional kidney. “The structure’s fine-scale tissue organization is realistic, but it does not adopt the macro-scale organization of a whole kidney. For example, it is not ‘plumbed’ into a waste drain, and it lacks large-scale features that are crucial for kidney function, such as a urine-concentrating medulla region. There is a long way to go until clinically useful transplantable kidneys can be engineered, but [this] protocol is a valuable step in the right direction.”

Davies also mentioned that these mini kidneys had the potential to replace “poorly predictive” animal drug safety tests, and called on researchers to team up with toxicologists to test the potential of their system.

Laboratory-Grown Kidneys Work in Laboratory Animals


A Jikei University School of Medicine research team based in Tokyo, Japan, led by Takashi Yokoo, in collaboration with scientists from Meiji University and St. Marianna University School of Medicine in Kawasaki, Keio University School of Medicine in Tokyo, and the School of Veterinary Medicine at Kitasato University in Towada, has shown that mini kidneys grown in vitro from human stem cells can be effectively connected to the excretory systems of rats and pigs.

This is not the first time that research groups have successfully grown mini kidneys in the laboratory. However, connecting these laboratory-grown organs to a laboratory animal’s excretory system constitutes a major technical challenge. The Jikei University team used an approach that employs a step-wise peristaltic ureter or SWPU to connect its lab-grown mini kidneys to the ureter of the transplant animal.

Previous attempts to use laboratory-grown kidneys in laboratory animals have failed because while the transplanted kidneys made urine, they were unable to pass that urine to the animal’s bladder and the kidneys swelled up and failed. Yokoo and his collaborators and colleagues used a stem cell method to make their mini kidneys, as others have in the past.  However, he and his team grew more than just the kidney for the host animal; that also grew a drainage tube, known as a ureter, as well, in addition to a  bladder to collect and store the urine.

Yokoo and others used laboratory rats as the incubators for their growing tissue.  When they connected the new kidney and its tubular systems to the animal’s existing bladder, the system worked.  Urine passed from the transplanted kidney into the transplanted bladder and then into the rat bladder.  The transplant was still working well when they checked eight weeks later.  Then Yokoo and others repeated their procedure in pigs, which are larger mammals than rats and better model systems for human beings.  Fortunately, they achieved the same results.

Although this technology is still years away from clinical trials with human patients, this work provides a paradigm for making organs in the laboratory that will work in sick people.  In the United Kingdom alone, more than 6,000 people are waiting for a kidney.  Because of a shortage of kidney donors, fewer than 3,000 transplants are carried out each year, and more than 350 people die each year waiting for a transplant.  Growing new kidneys using human stem cells could solve this problem.

“To our knowledge, this is the first report showing that the SWPU system may resolve two important problems in the generation of kidneys from stem cells: construction of a urine excretion pathway and continued growth of the newly generated kidney,” Yokoo and others wrote in their paper, which was published in the Proceedings of the National Academy of Sciences, USA, which was communicated to the journal by National Academy of Science member R. Michael Roberts from the University of Missouri-Columbia.

Stem cell expert Prof Chris Mason from University College London, said: “This is an interesting step forward. The science looks strong and they have good data in animals.  But that’s not to say this will work in humans. We are still years off that. It’s very much mechanistic. It moves us closer to understanding how the plumbing might work.  At least with kidneys, we can dialyse patients for a while so there would be time to grow kidneys if that becomes possible.”

Rebuilding Bladders with Cell-Free Materials


Ying-jian Zhud and Mu-jun Luan from the Shanghai Jiao Tong University in Shanghai, China teamed up to examine a new way to regenerate the bladder.

Several different synthetic and natural biomaterials have been pretty widely used in tissue regeneration experiments, particularly in the regeneration of the urinary bladder. The vast majority of this work has been done in rat model systems, which are fairly good animals to model bladder pathology and regeneration.

To date, the attempted reconstructive procedures don’t seem to work all that well, and this is due to the lack of appropriate scaffolding upon which cells can attach, grow and spread to form the new bladder tissue. Any scaffolding material for the bladder has to provide a waterproof barrier and it has to be able to support several different cell types. While this might not sound difficult on paper, it is in fact rather difficult. Some biomaterials might be well tolerated by the body, but cannot be fashioned into the shape of the organ. Others might support the growth of cells quite well, but are not tolerated by the body.

Zhud and Luan addressed these issues by turning to two different compounds that would compose a two-layered structure. Such a two-layered structure would support the cell types of the bladder. The outside layer was composed of silk fibroin, which is very moldable and usually well tolerated by cells. The inner layer consisted of a natural, acellular matrix (or BAMG for bladder acellular matrix graft). They used this two-layered structure to regenerate an injured bladder in rats.

First of all, it was clear that this material was relatively easy to make and it also could be nicely molded and sewn into the existing bladder. Tissue stains showed something even more interesting: the bilayer scaffold promoted the growth and recruitment of smooth muscles, blood vessels, and even nerves in a time-dependent manner. So by 12 weeks after implantation, bladders reconstructed with the bilayered matrix displayed superior structural and functional properties without significant local tissue responses or systemic toxicity.

Thus, the silk/BAMG scaffold could potentially be a promising scaffold for bladder regeneration. It shows good tissue compatibility, and allows the growth of cells on it. More work is required to take this to the next step, and the scaffold will undoubtedly undergo some changes. But this work represents a terrific start to what might be a superior scaffold for bladder regeneration.

Umbilical Cord Blood Mesenchymal Stem Cells Relieve the Symptoms of Interstitial Cystitis by Activating the Wnt Pathway and EGF Receptor


Interstitial tissue refers to the tissue that lies between major structures in an organ. For example, the tissue between muscles is an example of interstitial tissue.

Interstitial cystitis, otherwise known as painful bladder syndrome is a chronic condition that causes bladder pressure, bladder pain and sometimes pelvic pain, ranging from mild discomfort to severe pain.

The bladder is a hollow, muscular organ that stores urine and expands until it is full, at which time it signals the brain that it is time to urinate, communicating through the pelvic nerves. This creates the urge to urinate for most people. In the case of interstitial cystitis, these signals get mixed up and you feel the need to urinate more often and with smaller volumes of urine than most people. Interstitial cystitis most often affects women and can have a long-lasting impact on quality of life. Unfortunately no treatment reliably eliminates interstitial cystitis, but medications and other therapies may offer relief. There is no sign of bacterial infection in the case of bacterial cystitis.

A new study evaluated the potential of umbilical cord blood-derived mesenchymal stem cells or (UCB-MSCs) to treat interstitial cystitis (IC). In this study, Dr. Miho Song and colleagues from the Asan Medical Center, Seoul, South Korea, established a rat model of IC in 10-weeks-old female Sprague-Dawley rats by instilling 0.1M HCl or PBS (sham). After 1-week, human UCB-MSCs (IC+MSCs) or PBS (IC) were directly injected into the submucosal layer of the bladder.

To clarify this part of the experiment, the urinary bladder is made of several distinct tissue layers: a) The innermost layer of the bladder is the mucosa layer that lines the hollow lumen. Unlike the mucosa of other hollow organs, the urinary bladder is lined with transitional epithelial tissue that is able to stretch significantly to accommodate large volumes of urine. The transitional epithelium also provides protection to the underlying tissues from acidic or alkaline urine; b) Surrounding the mucosal layer is the submucosa, a layer of connective tissue with blood vessels and nervous tissue that supports and controls the surrounding tissue layers; c) The visceral muscles of the muscularis layer surround the submucosa and provide the urinary bladder with its ability to expand and contract. The muscularis is commonly referred to as the detrusor muscle and contracts during urination to expel urine from the body. The muscularis also forms the internal urethral sphincter, a ring of muscle that surrounds the urethral opening and holds urine in the urinary bladder. During urination, the sphincter relaxes to allow urine to flow into the urethra.

Bladder histology

Now a single subcutaneous injection of human UCB-MSCs significantly attenuated the irregular and decreased voiding interval in the IC group. In addition, the denudation of the epithelium that is characteristic of IC and increased inflammatory responses, mast cell infiltration, neurofilament production, and angiogenesis observed in the IC bladders were prevented in the IC+MSC group. Therefore, the injected UBC-MSCs prevented the structural changes in the bladder associated with the pathology of IC.

How did these cells do this? Further examination showed that the injected UCB-MSCs successfully engrafted to the stromal and epithelial tissues of the bladder and activated the Wnt signaling cascade. In fact, if the Wnt activity of these infused cells was blocked, the positive effects of the UCB-MSCs were also partially blocked. Additionally, activation of the epidermal growth factor receptor (EGFR) also helped UCB-MSCs heal the bladder. If the activity of the EGF receptor was inhibited by small molecules, then the benefits of MSC therapy were also abrogated. Also if both the Wnt pathway and EGFR were inhibited, the therapeutic capacities of UCB-MSCs were completely wiped out.

These data show the therapeutic effects of MSC therapy against IC in an orthodox rat animal model. However, this study also elucidates the molecular mechanisms responsible for these therapeutic effects. Our findings not only provide the basis for clinical trials of MSC therapy to IC, but also advance our understanding of IC pathophysiology.