Fat-derived cells Enhance the Bone-Forming Capacity of Hypertrophic Cartilage Matrices


Treating particular bone defects or injuries present a substantial challenges for clinicians. The method of choice usually involves the use of an “autologous” bone graft (“autologous” simply means that the graft comes from the patient’s own bone). However, autologous bone grafts have plenty of limitations. For example, if a patient has a large enough bone defect, there is no way the orthopedist and take bone from a donor site without causing a good deal of risk to the donor site. Even with small bone grafts, so-called “donor site morbidity” remains a risk. Having said that, plenty of patients have had autologous bone grafts that have worked well, but larger bone injuries or defects are not treatable with autologous bone grafts.

The answer: bone substitute materials. Bone substitute materials include tricalcium phosphate, hydroxyapatite, cement, ceramics, bioglass, hydrogels, polylactides, PMMA or poly(methy methacrylate) and other acrylates,, and a cadre of commercially available granules, blocks, pastes, cements, and membranes. Some of these materials are experimental, but others do work, even if do not work every time. The main problem with bone substitute materials is that, well, they are not bone, and, therefore lack the intrinsic ability to induce the growth of new bone (so-called osteoinductive potential) and their ability to integrate into new bone is also a problem at times.

We must admit that a good deal of progress has been made in this area and it’s a good thing too. Many of our fabulous men and women-at-arms have returned home with severe injuries from explosives and wounds from large-caliber weapons that have shattered their bones. These courageous men and women have been the recipient of these technologies. However, the clinician is sometimes left asking herself, “can we do better?”

A new paper from the laboratories of Ivan Martin and Claude Jaquiery from the University Hospital of Basel suggests that we can. This paper appeared in Stem Cells Translational Medicine and describes the use of a hypertrophic cartilage matrix that was seeded with cells derived from the stromal vascular faction of fat to not only make bone in the laboratory, but to also heal skull defects in laboratory animals. While this work benefitted laboratory animals, it was performed with human cells and materials, which suggests that this technique, if it can be efficiently and cheaply scaled up, might be usable in human patients.
The two lead authors of this paper, Atanas Todorov and Matthias Kreutz and their colleagues made hypertrophic cartilage matrices from human bone marrow mesenchymal stem cells (from human donors) that were induced to make cartilage. Fortunately, protocols have been very well worked out and making cartilage plugs with chondrocytes that are enlarged (hypertrophic) is something that has been successfully done in many laboratories. After growing the mesenchymal stem cells in culture, half a million cells were induced to form cartilage with dexamethasone, ascorbic acid 2-phosphate, and the growth factor TGF-beta1. After three weeks, the cartilage plugs were subjected to hypertrophic medium, which causes the cartilage cells to enlarge.

Chondrocyte enlargement is a prolegomena to the formation of bone and during development, many of our long bones (femur, humerus, fibula, radius, etc.), initially form as cartilage exemplars that are replaced by bone as the chondrocytes enlarge. Ossification begins when a hollow cylinder forms in the center of the bone (known as the periosteal collar). The underlying chondrocytes degenerate and die, thus releasing the matrix upon which calcium phosphate crystals accrete. The primary ossification center commences with the calcification of the central shaft of the bone and erosion of the matrix by the invasion of a blood vessel. The blood vessels bring osteoprogenitor cells that differentiate into osteoblasts and begin to deposit the bone matrix.

Next, Todorov and his crew isolated the stromal vascular fraction from fat that was donated by 12 volunteers who had fat taken from them by means of liposuction. The fat is then minced, digested with enzymes, centrifuged, filtered and then counted. This remaining fraction is called the stromal vascular fraction or SVF, and it consists of a pastiche of blood vessel-forming cells, mesenchymal stem cells, and bone-forming cells (and probably a few other cells types too). These SVF cells were seeded onto the hypertrophic cartilage plugs and used for the experiments in this paper.

First, the SVF-seeded plugs were used to grow bone in laboratory rodents. The cartilage plugs were implanted into the backs for nude mice. Different cartilage plugs were used that had been seeded with gradually increasing number of SVF cells. The implanted plugs definitely made ectopic bone, but the amount of bone they made was directly proportional to the number of SVF cells with which they had been seeded. Staining experimental also showed that some of the newly-grown bone came from the implanted SVF cells.

Ectopic bone formation. Grafts based on devitalized hypertrophic cartilage pellets were embedded in fibrin gel without or with stromal vascular fraction cells from adipose tissue and implanted subcutaneously in nude mice. (A): Representative hematoxylin and eosin, Masson-Tri-Chrome, and Safranin-O (Saf-O) staining and in situ hybridization for human ALU sequences (dark blue = positive) after 12 weeks in vivo. Saf-O stainings are blue-green because of lack of glycosaminoglycans and counterstaining with fast green. Osteoid matrix and bone marrow are visible. Scale bars = 200 µm. (B): Stainings for metalloproteinase (MMP)13 and MMP9, as well as for the N-terminal neoepitope at the major MMP cleavage site (DIPEN) after 12 weeks in vivo (red/pink = positive). Scale bars = 50 µm. +, osteoid matrix; ⋆, bone marrow. Abbreviations: ALU, Arthrobacter luteus; H&E, hematoxylin and eosin; Masson, Masson’s trichrome; MMP, metalloproteinase; Saf-O, Safranin-O; SVF, stromal vascular fraction.
Ectopic bone formation. Grafts based on devitalized hypertrophic cartilage pellets were embedded in fibrin gel without or with stromal vascular fraction cells from adipose tissue and implanted subcutaneously in nude mice. (A): Representative hematoxylin and eosin, Masson-Tri-Chrome, and Safranin-O (Saf-O) staining and in situ hybridization for human ALU sequences (dark blue = positive) after 12 weeks in vivo. Saf-O stainings are blue-green because of lack of glycosaminoglycans and counterstaining with fast green. Osteoid matrix and bone marrow are visible. Scale bars = 200 µm. (B): Stainings for metalloproteinase (MMP)13 and MMP9, as well as for the N-terminal neoepitope at the major MMP cleavage site (DIPEN) after 12 weeks in vivo (red/pink = positive). Scale bars = 50 µm. +, osteoid matrix; ⋆, bone marrow. Abbreviations: ALU, Arthrobacter luteus; H&E, hematoxylin and eosin; Masson, Masson’s trichrome; MMP, metalloproteinase; Saf-O, Safranin-O; SVF, stromal vascular fraction.

In the second experiment, Todorov and Kreutz used these SVF-seeded cartilage plugs to repair skull lesions in rats. Once again, the quantity of bone produced was directly proportional to the number of SVFs seeded into the cartilage matrices prior to implantation. In both experiments, the density of SVF cells positively correlates with the bone-forming cells in the grafts and the percentage of SVF-derived blood vessel-forming cells correlates with the amount of deposited mineralized matrix.

Bone repair capacity. Devitalized hypertrophic cartilage pellets were embedded in fibrin gel without or with stromal vascular fraction (SVF) cells from adipose tissue and implanted in rat calvarial defects. (A): Mineralized volume quantified by microtomography (n = 9 grafts assessed per group). (B): Bone area assessed in histological sections, expressed as percentage of total defect area (n = at least 24 sections assessed per group). ∗∗∗∗, p < .0001. (C, D): Representative three-dimensional microtomography reconstructions (left) and hematoxylin/eosin (H&E) staining (right) of the calvarial defects filled with devitalized grafts, implanted without (C) or with (D) activation by SVF cells after 4 weeks. Dotted circles indicate the defect borders (4 mm diameter). Scale bars = 500 µm. (E): Microtomography (left) and H&E staining (middle and right) displaying the bridging between hypertrophic matrix and bone of the calvarium, or the fusion of single pellets (right) in activated grafts. White bar = 850 µm; black bars = 500 µm. Dotted lines indicate the edge of the calvarium. (F): In situ hybridization for Arthrobacter luteus sequences showing the presence of human cells (dark blue, positive) in the explants. Scale bar = 200 µm. Abbreviations: C, calvarium; dev, fibrin gel without stromal vascular fraction; dev + SVF, fibrin gel with stromal vascular fraction; P, hypertrophic matrix; SVF, stromal vascular fraction.
Bone repair capacity. Devitalized hypertrophic cartilage pellets were embedded in fibrin gel without or with stromal vascular fraction (SVF) cells from adipose tissue and implanted in rat calvarial defects. (A): Mineralized volume quantified by microtomography (n = 9 grafts assessed per group). (B): Bone area assessed in histological sections, expressed as percentage of total defect area (n = at least 24 sections assessed per group). ∗∗∗∗, p < .0001. (C, D): Representative three-dimensional microtomography reconstructions (left) and hematoxylin/eosin (H&E) staining (right) of the calvarial defects filled with devitalized grafts, implanted without (C) or with (D) activation by SVF cells after 4 weeks. Dotted circles indicate the defect borders (4 mm diameter). Scale bars = 500 µm. (E): Microtomography (left) and H&E staining (middle and right) displaying the bridging between hypertrophic matrix and bone of the calvarium, or the fusion of single pellets (right) in activated grafts. White bar = 850 µm; black bars = 500 µm. Dotted lines indicate the edge of the calvarium. (F): In situ hybridization for Arthrobacter luteus sequences showing the presence of human cells (dark blue, positive) in the explants. Scale bar = 200 µm. Abbreviations: C, calvarium; dev, fibrin gel without stromal vascular fraction; dev + SVF, fibrin gel with stromal vascular fraction; P, hypertrophic matrix; SVF, stromal vascular fraction.

This is not the first time scientists have proposed the use of cartilage plugs to induce the formation of new bone. Van der Stok and others and Bahney and colleagues were able to repair segmental bone defects in laboratory rodents. Is this technique transferable to human patients? Possibly. Hypertrophic cartilage is relatively easy to make and it is completely conceivable that hypertrophic cartilage wedges can be sold as “off-the-shelf” products for bone treatments. SVF can also be derived from the patient or can be derived from donors.

Furthermore, the protocols in this paper all used human cells and grew the products in immunodeficient rats and mice. Therefore, in addition to scaling this process up, we have a potentially useful protocol that might very well be adaptable to the clinic.

The efficacy of this technique must be confirmed in larger animal model system before human trials can be considered. Hopefully human trials are in the future for this fascinating technique.

Fat-Based Mesenchymal Stem Cell-Seeded Matrix Heals Bronchopleural Fistula in Female Cancer Patient


Bronchopleural fistulae, mercifully abbreviated as BPF, refers to an opening or hole in the respiratory tree that causes continuity between the pleural space that surrounds the lungs and the bronchial tree. BPH is a highly feared complication of surgery on the respiratory system.

BPH can complicate surgical resection of the pulmonary system. Patients with lung cancers may require lung resection in order to remove tumorous lung tissue. The rate of BPH incidence after lung surgery varies widely, with reported incidences ranging from 1.5 to 28%. Necrosis or death of lung tissue as a result of infection can also cause BPH, as can tuberculosis. Chemotherapy or radiation therapy for lung cancers can also result in BPF. Finally, BPF may caused by persistent spontaneous pneumothorax, which refers to an abnormal build up of air or other gases in the pleural space, which causes an uncoupling of the lung from the chest wall.

To date, treatment for BPF is only partially effectively. The main treatment includes surgery, but the rate of recurrence of the fistulae remains rather high as do the rate of mortality. Can stem cells show us a better way?

Perhaps they can. Dennis A. Wigle, a surgeon at Mayo Clinic, and his collaborators used a synthetic bioabsorbable matrix seeded with the patients one fat-based mesenchymal stem cells to heal a BPF in a 63-yr old woman. Mind you, this is a case study (the lowest quality clinical evidence) and not a controlled study,. However, the success of this case study is at least suggestive that such an approach might prove useful for patients who suffer from BPFs.

Microscopic assessment of matrix cell seeding. (A): Ethidium bromide (red) and Syto-13 (green) costain demonstrating live and dead cells on mesenchymal stem cell seeding on matrix. (B): Confocal microscopy with CD90 (Thy-1) fluorescein isothiocyanate (green) and Hoechst 33342 (trihydrochloride trihydrate) (blue) fluorescent nuclear staining. These images were captured using a ×20 objective and a ×10 eyepiece, for a combined magnification of ×200. Scale bar = 150 µm.
Microscopic assessment of matrix cell seeding. (A): Ethidium bromide (red) and Syto-13 (green) costain demonstrating live and dead cells on mesenchymal stem cell seeding on matrix. (B): Confocal microscopy with CD90 (Thy-1) fluorescein isothiocyanate (green) and Hoechst 33342 (trihydrochloride trihydrate) (blue) fluorescent nuclear staining. These images were captured using a ×20 objective and a ×10 eyepiece, for a combined magnification of ×200. Scale bar = 150 µm.

A 63-yr old woman who had surgical resection of the lung in order to treat her lung cancer had, as a consequence of her surgery, a BPF. Some 30 different surgical attempts were made to repair the BPF, but all of them failed. The woman’s health declined and her medical team started to think of alternative treatments.

Fortunately, Mayo Clinic has been participating in an ongoing clinical trial to use fat-based mesenchymal stem cells to treat anal fistulae in Crohn’s disease patients. Therefore Dr. Wigle and his team considered using the protocol utilized with Crohn’s patients to repair this woman’s BPF.

Fat biopsies were taken from the patient and the fat was washed, minced, digested with enzymes, and then grown in special culture media. The adipose tissue-derived mesenchymal stem cells (AD-MSCs) grew and were isolated, characterized and shown to be MSCs.

These cells were then seeded on a matrix of synthetic bioabsorbable poly(glycolide-trimethylene carbonate) copolymer and then placed in a bioreactor to grow. After about 4 days, the matrix was flush with AD-MSCs, and this cell-seeded patch was then used in a subsequent surgery to seal the opening in the respiratory tree. This time the surgery worked. The patient was discharged 25 days after the surgery and sent home.

MRIs of the respiratory system showed that the BPF had indeed closed and properly resolved.

Preoperative imaging showing size and location of fistula, and postoperative imaging demonstrating disease resolution. (A): Preoperative bronchoscopy demonstrating large bronchopleural fistula (BPF) cavity and lateral extension of fistula tracts. (B): Postoperative bronchoscopy (3 months) demonstrating progressive healing of BPF site. (C): Preoperative computed tomography scan demonstrating large BPF with connection to atmosphere (additional axial slices inferiorly). (D): Postoperative computed tomography scan (16 months) demonstrating resolution of BPF.
Preoperative imaging showing size and location of fistula, and postoperative imaging demonstrating disease resolution. (A): Preoperative bronchoscopy demonstrating large bronchopleural fistula (BPF) cavity and lateral extension of fistula tracts. (B): Postoperative bronchoscopy (3 months) demonstrating progressive healing of BPF site. (C): Preoperative computed tomography scan demonstrating large BPF with connection to atmosphere (additional axial slices inferiorly). (D): Postoperative computed tomography scan (16 months) demonstrating resolution of BPF.

This case study might confirm what was previously observed in large animal studies by Petrella and others, namely that AD-MSCs can be used to heal BPF. Petrella and others theorized that implanted MSCs induce the proliferation of fibroblasts that then deposit collagen, which seals the BPF (see Ann Thorac Surg 97:480483.  Alternatively, AD-MSCs might differentiate into cell types  required for regeneration of the airways (Dominici M, and others, Cytotherapy 8:315317).  Either way, this paper seems to suggest that AD-MSCs can be isolated from a patient’s fat (even a very sick patient like this one) without incident and used for tissue engineering applications that can repair very serious wound like BPF. 

This paper was published in: Johnathon M., Aho, et Al., “Closure of a Recurrent Bronchopleural Fistula Using a Matrix Seeded With Patient-Derived Mesenchymal Stem Cells.” Stem Cells Trans Med October 2016 vol. 5 no. 10 1375-1379. 

New Stem Cell Treatment for Bronchopleural Fistulas


Mayo Clinic researchers have made history by using a patient’s own stem cells to heal an open wound on the upper chest of a patient that had been caused by postoperative complications of lung removal.

A hole in the chest that opens to the outside is called a bronchopleural fistulae. Such wounds are holes that lead from large airways in the lungs to the membrane that lines the lungs.

Unfortunately, present treatments for bronchopulmonary fistulae tend to be terribly successful and death from such injuries are all too common.

According to Dr. Dennis Wigle, a Mayo Clinch Researcher, “Current management is not reliably successful. After exhausting therapeutic options, and with declining health of the patient, we moved toward a new approach. The protocol and approach were based on an ongoing trial investigating this method to treat anal fistulas in Cohn’s disease”.

So Dr. Wigle and his colleagues harvested stem cells from the belly fat of their patient and seeded onto a bioabsorbable mesh that was surgically implanted at the site of the fistula.

Follow-up imaging of the patient showed that the fistula had closed and remained healed. More than a year-and-a-half later, the patient remains asymptomatic and has been able to resume activities of daily living.

In their paper, Wigle and others describe their patient, a 63-year-old female patient, who was referred to Mayo Clinic for treatment of a large bronchopleural fistula.

Because present therapies offer little relief, Wigle and his team turned to regenerative therapies in order to try a more innovative treatment.

“To our knowledge, this case represents the first in human report of surgically placed stem cells to repair a large, multiple recurrent bronchopleural fistula. The approach was well tolerated suggesting the potential for expanded use,” said Dr. Wigle.

While this procedure was successful in this case, it is unclear if this treatment was the main contributor to the healing of the wound. Since this is a single-patient case study and not a double blinded, placebo-controlled study, it is lower-quality evidence.

However, Wigle and others hope to further examine this technique, and in particular, the use a patient’s own stem cells, to treat fistulae in the respiratory system.

This case study was published in Stem Cells Translational Medicine, June 2016 DOI:10.5966/sctm.2016-0078.

Phase I Clinical Trial of Fat-Based Mesenchymal Stem Cells for Severe Osteoarthritis


In the July 2016 edition of the journal Stem Cells Translational Medicine, a report has been published that lays out the results of a phase I clinical trial that used mesenchymal stem cells from a patient’s own fat tissues to treat osteoarthritis of the knee.  This study was not placebo controlled, but did examine the effects of escalated doses on the patient.  The main  investigator for this trial was Dr. Christian Jorgensen from Lapeyronie University Hospital in Montpellier, France.

Osteoarthritis (OA) is the most common musculoskeletal condition in adults and it can cause a good deal of pain and disability.

Joints like the knee consist of a junction between two or more bones.  The ends of these bones are capped by layer of cartilage called “hyaline cartilage” that serves as a shock absorber.  Larger joints like the knee, shoulder, and hip are encased in a sac called the “bursa” that is filled with lubricating synovial fluid.

Knee

OA involves damage and/or destruction of the cartilage caps at the ends of long bones, and erosion and ultimately permanent changes in the structure of bone that underlies the cartilage at the end of the bone. The knee loses its shock absorbers and lubricators and becomes a grinding, inflamed, painful caricature of its former self.

To treat OA, most orthopedic surgeons will replace the damaged knee with an artificial knee that is attached the upper (femur) and lower (tibia and fibula) bones of the leg.  This procedure, arthroplasty, reconstructs the knee with artificial materials that form synthetic joints.  Alternatively, some enterprising physicians have tried to use stem cells from bone marrow to repair eroded cartilage in the knees of OA patients.  Christopher Centeno and his colleagues at his clinic near Denver, CO and affiliated sites have pioneered procedures for OA patients.  However, Dr. Centeno remains skeptical of the ability of stem cells from fat to treat patients with OA.

In animal studies, OA of the knee can be induced by injected tissue-destroying enzymes.  If laboratory mice that received injectionof these enzymes into their knees are then treated with fat-based mesenchymal stem cells, the effects and symptoms of OA do not appear (ter Huurne M, et al. Arthritis Rheum 2012; 64:3604-3613).  In another study in rabbits, injections of 2-6 million fat-derived mesenchymal stem cells into the knee-joint of rabbits suffering from OA improved cartilage health and inhibited cartilage degradation.  These administered cells also reduced inflammation in the knee (Desando G., et al., Arthritis Res Ther 2013; 15:R22).  Therefore, fat-based mesenchymal stem seem to have some ability to ameliorate the effects and consequences of OA, at least in preclinical studies.  This trial is the beginnings of what will hopefully be a series of experiments that will assess the ability (or inability) to treat OA patients.

18 patients were enrolled from an initial pool of 48 candidates who all suffered from severe, symptomatic OA of the knee.  Six patients received 2 million mesenchymal stem cells isolated from their own fat, 6 others received ten million mesenchymal stem cells isolated from their own fat, and the final group of 6 OA patients received 50 million mesenchymal stem cells isolated from their own fat tissues.  These mesenchymal stem cells were isolated from the patient’s fat that was collected by means of liposuction.  The fat was then processed by means of a standard protocol that is used to isolated mesenchymal stem cells from human fat (see Bura A, et al., Cytotherapy 2014; 16:245-257).  All patients received their stem cells by means of injection into the knee-joint (inter-articular injections).

Because this is a Phase I clinical trial, assessing the safety of the procedure is one of the main goals of this study.  No adverse effects were associated with either the liposuction or the interarticular injections.  The article even states: “Laboratory tests, vital signs and electrocardiograms indicated no local or systemic safety concerns.”. Four patients experienced slight knee pain and joint effusion that either resolved by itself or with treatment with a nonsteroidal antinflammatory drug (think ibuprofen).  Therefore it seems fair to conclude that this procedure seems safe, but a larger, placebo-controlled study is still required to confirm this.

As to the patient’s clinical outcomes, 17 of the 18 patients elected to forego total knee replacement.  All patients showed improvement in pain and knee functionality at 1 week, 3 months and 6 months after the procedure.  However, only the low-dose group showed improvements that were statistically significant.

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WOMAC pain and function improvement during the study (WOMAC = Western Ontario and McMaster Universities Arthritis Index)

WOMAC pain and function improvement during the study. Abbreviation: WOMAC, Western Ontario and McMaster Universities Arthritis Index.

Seven of the patients treated in Germany (11 patients were treated in France and 7 were treated in Germany) were also examined with Magnetic Resonance Imaging (MRI) before and 4 months after the procedure.  Six of the seven patients showed what could be interpreted as improvements in cartilage.

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dGEMRIC and T1rho magnetic resonance imaging (MRI) of selected patients. The graphs on the left show the dGEMRIC (n = 6) and T1rho (n = 5) values before and 4 months after cell therapy. Increasing dGEmRIC and decreasing T1rho values are each known to correspond to increasing glycosaminoglycan/proteoglycan content and thus improved cartilage condition. On the right, the corresponding dGEMRIC and T1rho maps are shown as a color-coded overlay on an anatomical MRI for a patient receiving a low cell dose. The observed values in the cartilage change in the time course can be easily seen and correspond to an increase in cartilage condition. Abbreviation: dGEMRIC, delayed gadolinium-enhanced magnetic resonance imaging of cartilage.

Tissue biopsies of 11 of the 18 patients revealed an absence of significant inflammation, but some patients (4-5) showed signs of weak or moderate inflammation.  One patient showed what seemed to be a sheet of MSC cells on the surface of the cartilage.

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Histologic findings. (A): Vascular congestion and weak lymphocytic infiltrate of the synovial (case 8) (magnification, ×50). (B): Osteoarthritic cartilage OARSI grade >3 (case 4) (×25). (C): Toluidine blue staining (case 2) (magnification, ×100). (D): Stem cell stroma shows an Alcian blue depleted matrix compared with the strong staining of osteoarthritic cartilage (case 2) (magnification, ×100). (E): Weak PS100 staining of possible stem cells on the cartilage surface and strong PS100 staining of chondrocytes (case 2) (magnification, ×100). Abbreviations: OARSI, Osteoarthritis Research Society International.

The primary outcome of this study – the safety of interarticular injections of fat0-based mesenchymal stem cells – seems to have been satisfied.  This is similar to the safety profiles of such cells in clinical trials that have used fat-based mesenchymal stem cells to treat fistulae in inflammatory bowel disease (Bura A, et al., Cytotherapy 2014; 16: 245-257) or critical limb ischemia (Lee WY and others, Stem Cells 2013; 31:2575-2581).  Also, patients showed improvements in pain and functionality.  Even though there was no placebo in this study, a double-blinded, placebo-controlled study that examined the use of efficacy of interarticular hyaluronic acid injections showed a smaller decreased in pain score that what was observed in this case (22.9 ± 1.4 vs 30.7 ± 10.7).  It is doubtful that the injected mesenchymal stem cells made much cartilage but instead quelled inflammation and stimulated resident stem cell populations to repair damage in the knee.

This study is small and is not placebo controlled, however, the hopeful results do warrant a larger, phase 1/2 placebo-controlled study that is apparently already underway.

An even more intriguing project might be to prime the isolated mesenchymal stem cells to make cartilage and then use live fluoroscopy to overlay the cells on the actual cartilage lesions.  While this is a more exacting procedure, it is the way Centeno and his group are using stem cells to treat their patients, and a true head-to-head study of the efficacy of fat-based mesenchymal stem cells versus bone marrow-based mesenchymal stem cells would be immensely useful.

Fat-Derived Stem Cells Form Muscle in Muscular Dystrophy Mice


Stem cell therapy for Duchenne muscular dystrophy (DMD) has been plagued by poor cell engraftment into diseased muscles. Additionally, there are no reports to date describing the efficient generation of muscle progenitors from fat-derived stem cells (ADSCs) that can contribute to muscle regeneration.

A study by Cheng Zhang and others from Sun Yat-sen University in Guangzhou, China, Guangdong Province has examined the ability of progenitor cells differentiated from ADSCs using forskolin, basic fibroblast growth factor, the glycogen synthase kinase 3β inhibitor 6-bromoindirubin-3′-oxime as well as the supernatant of ADSC cultures to form workable muscle cells.

When these fat-derived stem cells were treated as described above, they formed a proliferative population of muscle progenitors from ADSCs that had characteristics similar to muscle satellite cells. Furthermore, in culture, these cells were capable of terminal differentiation into multinucleated myotubes.

When these fat-derived stem cells were transplanted into mice that had an inherited type of DMD, the progenitor cells successfully engrafted in skeletal muscle for up to 12 weeks, and generated new muscle fibers, restored dystrophin expression, and contributed to the satellite cell compartment.

These findings highlight the potential application of ADSCs for the treatment of muscular dystrophy. They also illustrate the ability of ADSCs to differentiate into functional skeletal muscle cells when treated properly in culture. These same cells might serve as a treatment for DMD patients.

This article was published in Hum. Mol. Genet. (2015) doi: 10.1093/hmg/ddv316.

Fat-Based Stem Cells Speed the Healing of Bed Sores in Animals


Pressure ulcers, which are also knows as bedsores (or decubitus ulcers) are localized injuries to the skin that can also include the underlying tissue that usually occur as a result of pressure, or pressure in combination with rubbing or friction. They tend to occur some sort of bony prominence such as elbows, hips, shoulders, ankles, back of the head, and other such places. More than 2.5 million patients each year in the U.S. require treatment for pressure ulcers, and the elderly are at particularly high risk for these lesions. Currently, therapies for pressure ulcers consist of conservative medical management for shallow lesions and aggressive debridement and surgery for deeper lesions.

Jeffery Gimble and his colleagues from the Tulane University School of Medicine in New Orleans, Louisiana, used a mouse model for pressure ulcers to test the ability of fat-derived stromal/stem cell treatment to accelerate and enhance the healing of pressure ulcers.  The dorsal skin of both young (2 months old) and old (20 months old) C57BL/6J female mice was pinched between external magnets for 12 hours over 2 consecutive days. This treatment initiated a pressure ulcer, and one day after induction of the pressure ulcers, some of these mice were injected with fat-derived stromal stem cells that had been isolated from healthy mice that were of the same genetic lineage as the injured mice. However, the donor mice were genetically engineered to express a green fluorescent protein in all their tissues. Other mice were treated with injections of saline-treated controls.

The mice that were injected with fat-derived stromal/stem cells displayed a cell-concentration-dependent acceleration of wound closure. The cell-injected mice also showed improved epidermal/dermal architecture, increased fat deposition, and reduced inflammation at the sites of injury. Interestingly, these fat-derived stem cell-induced improvements occurred in both young and elderly mice. However, the gene expression profile of genes involved in the making of blood vessels, regulating the immune system, and tissue repair differed according to the age of the mice, with younger mice making more of these genes that their older counterparts. These results are consistent with clinical reports of the improved skin architecture after fat grafting in patients with thermal injuries.

This current proof-of-principle study sets the stage for clinical translation of the transplantation of fat-based stem cells as a treatment of pressure ulcers.

A Patient’s Own Stem Cells Treats Their Crohn’s Disease


Stem cells isolated from the fat of patients with Crohn’s disease, an inflammatory disease of the bowel, relieved them from fistulas, which are a common, and potentially dangerous side effect of the disease. This is according to the results of a phase 2 clinical trial published in the latest issue of STEM CELLS Translational Medicine (SCTM).

Patients with Crohn’s disease suffer from a painful, chronic disease in which the body’s immune system attacks its own gastrointestinal tract. In Crohn’s patients, inflammation within the bowel can sometimes extend completely through the intestinal wall and create a what is known as a “fistula.”. Fistulas are abnormal connections between the intestine and another organ or even the skin. If left untreated, a fistula can become infected and form an abscess that can be life threatening.

Chang Sik Yu, M.D., Ph.D., of the Asan Medical Center in Seoul, Korea, who is a senior author of the SCTM paper, describes the results of a clinical trial that was conducted in collaboration with four other hospitals in South Korea. According to Dr. Yu: “Crohn’s fistula is one of the most distressing diseases as it decreases patient’s quality of life and frequently recurs. It has been reported to occur in up to 38 percent of Crohn’s patients and over the course of the disease, 10 to 18 percent of them must undergo a proctectomy, which is a surgical procedure to remove the rectum.”

Overall, the treatments currently available for Crohn’s fistula remain unsatisfactory because they fail to achieve complete closure, lower recurrence of the fistulas and do not limit adverse effects, Dr. Yu said. Given the challenges and unmet medical needs in Crohn’s fistula, attention has turned to stem cell therapy as a possible treatment.

Several studies, including those undertaken by Dr. Yu’s team, have shown that mesenchymal stem cells (MSCs) do indeed improve Crohn’s disease and Crohn’s fistula. Their phase II trial enrolled 43 patients for a term of one year, over the period from January 2010 to August 2012. These patients received injections of their own fat-based MSCs, and 82 percent of them experienced complete closure of fistula eight weeks after the final ASC injection. 75 percent of the trial participants remained fistula-free two years later.

“It strongly demonstrated MSCs derived from ASCs are a safe and useful therapeutic tool for the treatment of Crohn’s fistula,” Dr. Yu said.

The latest study was intended to evaluate the long-term outcome by following 41 of the original 43 patients for yet another year. Dr. Yu reported, “Our long-term follow-up found that one or two doses of autologous ASC therapy achieved complete closure of the fistulas in 75 percent of the patients at 24 months, and sustainable safety and efficacy of initial response in 83 percent. No adverse events related to ASC administration were observed. Furthermore, complete closure after initial treatment was well sustained.”

“These results strongly suggest that autologous ASCs may be a novel treatment option for Crohn’s fistulae,” he said.

“Stem cells derived from fat tissue are known to regulate the immune response, which may explain these successful long-term results treating Crohn’s fistulae with a high risk of recurrence,” said Anthony Atala, M.D., Editor-in-Chief of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine.