Treating Hypoplastic Left Heart Syndrome with Tissue Engineered Blood Vessels


Angela Irizarry is four-years old and was born with a congenital heart condition called Hypoplastic Left Heart Syndrome (HLHS). HLHS causes the main pumping chamber of the heart, the left ventricle to be abnormally small and stunted. Therefore, the heart only has one pumping chamber, and such a condition is potentially fatal.

HLHS affects approximately 3,000 babies in the US alone each year. Since babies with HLHS have an underdeveloped left side of the heart, the right side of the heart must pump blood to both the lungs and the rest of the body. Before the baby is born, the lungs are not being used because the placenta provides the oxygen for the baby and the baby is surrounded by amniotic fluid. Therefore, the lungs are bypassed by a connection between the vessels that extend from the right side of the heart to the lungs and the vessel that extends from the left side of the heart. This bypass is called the “ductus arteriosus.” The ductus arteriosus and a hole is the septum that separates the left and right side of the heart close very soon after birth (1-2 days after birth). In some children, the ductus arteriosus does not close, which is called patent ductus arteriosus (PDA). Once the ductus arteriosus closes in children who have HLHS, the right side of the heart can’t pump blood out to the rest of the body. The undeveloped heart cannot pump efficiently enough to support the life of the child, and the baby becomes very sick and may die within the first days of life.

Without two heart chambers pumping blood throughout the entire body, HLHS babies can’t deliver sufficient levels of oxygen to their organs and extremities. This severely affects their development and also causes them to turn blue and suffer from a lack of energy. According to Dr. Breuer, without a surgical repair, 70% of them die before their first birthday.

Surgical treatment of HLHS occurs in three stages. The first stage is the Norwood procedure, which is done during the first week of life. The Norwood procedure reconstructs the aortic arch, which is the main blood vessel that supplies blood to the body. Surgeons also insert a tube to connect the aorta to the blood vessel that supplies the lungs (the pulmonary artery). This shunt allows the right side of the heart to pump blood into the aorta.

The second stage is performed when the baby is 4-6 months old and is called the bidirectional Glenn procedure or hemi-Fontan. In this surgery, some of the veins that carry blood from the body are connected to blood vessels that carry blood to the lungs. This allows most of the blood to flow directly from the body into the lungs, and reduces the workload of the right side of the heart. Because blood with higher levels of oxygen is pumped into the aorta, it supplies the rest of the body with oxygen-rich blood.

The third stage is carried out when the child is 18-48 months old, and is known as the Fontan procedure. The Fontan procedure takes the remaining blood vessels that carry blood from the body and connects them to the blood vessels that carry blood to the lungs. This ensures that ALL the blood returning from the body receives oxygen in the lungs and also ends the mixing of oxygen-rich blood with oxygen-poor blood. This operation improves the general health of the child and also prevents from having the blue look.

These surgeries are traumatic, and expensive. Not all children survive them. Is there a better way? In Angela’s case, physicians have used stem cells to help Angela grow a new blood vessel in her body. This experimental treatment could rapidly advance the burgeoning field of regenerative medicine.

In August of 2011, Doctors at Yale University implanted a bioabsorbable tube into Angela’s chest. This tube is designed to dissolve over time, but before the implantation procedure, the tube was seeded with stem cells and other cell types that had been harvested from Angela’s bone marrow. Doctors are quite confident that the tube has disappeared, but in its place, a new blood vessel was built from the bones of the bioabsorbable tube. Apparently, this tube functions like a normal blood vessel.

Christopher Breuer, the Yale pediatric surgeon who led the 12-hour procedure to implant the device, commented, “We’re making a blood vessel where there wasn’t one. We’re inducing regeneration.” Before the procedure, Angela had little energy or endurance. Now, even though she is on several medications, she has the spunk of a regular child her age. Dr. Breuer and her parents are confident that she will be able to start school in the fall.

Recent advances in stem-cell science, regenerative medicine, and tissue engineering suggest that regenerative forces in our bodies that are lost soon after birth might be reawakened with strategically implanted stem cells and other tissue. This hope is fueling research at many academic laboratories and dozens of start-up companies. At these laboratories, scientists are racing to find effective ways to treat previously intractable maladies including paralysis due to spinal cord injuries, poor-functioning kidneys and bladders, and heart muscle damaged from heart attacks.

Also, regenerative medicine seeks to improve presently available treatments. For example, in the case of the Fontan procedure, pediatric surgeons implanting a synthetic blood vessel made of Gore-Tex in order to reroute blood from the lower extremities directly to the lungs instead of through the heart. While this works, this device prone to causing blood clots, infection and in some cases, the child needs additional surgeries later in life to increase the size of the blood vessels to accommodate the growth of the child. Dr. Breuer wants to create a natural conduit for blood that reduces the complications associated with a synthetic tube and grows with the child.

Though not involved in this study, Robert Langer, a researcher at Massachusetts Institute of Technology and a regenerative-medicine pioneer, called Angela’s case a “real milestone and broadly important for the field of tissue engineering.”  Langer also added, “It gives you hope that when you combine cells with a scaffold and [put] them in the body, they will do the right thing.”

According to Claudia, Angela’s mother, the heart defect was diagnosed when she (Claudia) was five months pregnant. Angela had her first operation when she was 5 days old, and the second when she was 8-months old. However, she heart defect still sapped her energy and stunted her growth. Angela was shy, small for her age and lacked the stamina of a normal 3-year-old. According the Claudia, “If she ran from [the living room] to the kitchen, she got tired and she had purple lips.”

Dr. Breuer and other Yale staff met with Angela and her family four times. They discussed the advantages and risks associated with conventional synthetic tubes versus this new, bioengineered approach. Dr. Breuer said that a tissue-engineered blood vessels can still narrow or become blocked and other complications might also arise (e.g., cancer, immune system troubles etc.) that are difficult to foresee. According to Claudia Irizarry, who works as a church secretary, the family’s faith in God and their doctors influenced them to choose the bioengineered version over the synthetic version.

To say the least they are glad they did. According to Angela’s father, Angel Irizarry, who works as a carpenter, his daughter seems more like a regular kid, according to her. “It’s a huge difference,” he says. “It’s like going from a four-cylinder to an eight-cylinder car in one operation.” Before the surgery, he added, “her eyes weren’t as happy as [they are] now.”

It took Dr. Breuer four years of tedious work after he joined Yale in 2003 to develop his bioengineered blood vessel. After those four years, he sought approval from the U.S. Food and Drug Administration in 2007 to test his approach on patients. It took another four years and 3,000 pages of data before the agency allowed him to conduct his first human trials. Breuer’s clinical trial builds on the cases of 25 children and young adults who were successfully treated in Japan a decade ago with a similar approach. Dr. Breuer hopes to implant his tissue-engineered blood vessel into a second patient soon as part of a six-patient Phase I/II clinical trial that examines the safety of the procedure and determine if the blood vessels actually grow as the child gets grows. Breuer hopes that treatment in these patients is non-problematic. If so, then it might qualify for special FDA humanitarian device exemption.

Stem Cells Allow Kidney Transplant Recipients to Live Without Anti-Rejection Drugs


Researchers from Northwestern Medicine And University of Louisville are in the midst of a clinical trial to examine the use of stem cell infusions to re-educate the immune system of recipients of transplanted organs. Such re-education of the immune system might completely eliminate the need for anti-rejection medicines.

Organ transplant recipient must take several pills each day for the remainder of their lives. These medicines are drugs that suppress the immune system, and these drugs have many undesirable side effects. Prolonged use of these drugs can cause high blood pressure, diabetes, infections, heart disease, and cancer. Therefore a stem cell-based approach that obviates the need for drugs that inhibit the immune system would offer transplant recipients better quality of life and few health risks for transplant patients.

Joseph Leventhal, a transplant surgeon at Northwestern Memorial Hospital said, “The preliminary results are exciting and may have a major impact on organ transplantation in the future. With refinement, this approach may prove to be applicable to the majority of patients receiving the full spectrum of solid organ transplants.” Leventhal is the main author of this study in collaboration with Suzanne Ildstad, who is the director of the Institute of Cellular Therapeutics at the University of Louisville. The study is, in fact, one of the first of its kind, since it does not require that the organ donor and recipient do not have to be tissue matched.

For standard kidney transplants, the organ donor, who has agreed to donate a kidney, provides their kidney for transplantation to the recipient. In this study, the organ donor not only provides a kidney, but also a small quantity of blood cells. Approximately one month before the transplant, the organ donor gives some bone marrow by means of a procedure called “apheresis.”

Apheresis removes whole blood from a patient, and then uses a centrifuge-like instrument to separate blood components. These separated portions are removed and the remaining components used for retransfusion. The blood components are separated into fluids, otherwise known as plasma, platelets, and white blood cells. From the white cell fraction, a group of cells that the study cells “facilitating cells” are isolated. The organ recipient’s bone marrow is partially ablated with radiation.

The kidney is then transplanted into the recipient’s body, and one day later, the facilitating cells are given to the recipient. Because the organ recipient’s bone marrow has been semi-ablated, the facilitating cells have space to grow without competition from the recipient’s bone marrow. The goal of this is to make within the recipient two bone marrow stem cell systems that are completely functional in one person. The patient is given anti-immune system drugs, but he or she is slowly weaned off them, with the goal of all anti-rejection drugs being ended within one year of the transplant. To qualify for this study, patients must have compatible blood types

Ildstad provided this insight, “This is something I have worked for my entire life.”  Ildstad pioneered the discovery of the “facilitating cell.”  This trial is ongoing, but the initial results are immensely encouraging, since some transplant patients seem to not need their anti-rejection medicines anymore even though they now have a kidney inside them that was not tissue matched.  Specifically, five of eight people who underwent this treatment protocol were able to stop all immunosuppressive therapy within a year after their kidney and stem-cell transplants,. Note that four of these five patients received kidneys that came from unrelated donors. Notably, all of these patients maintained entirely donor-derived immune systems with no signs of Graft-versus-Host disease.  Ildstad and her team have since treated seven more people. “We continue to see good results,” she says. This could easily revolutionize solid organ transplantation.

Amniotic Stem Cells Are Used With Biomaterials to Fabricate Functional New Heart Valves


When children are born with abnormally formed heart valves, their prognosis is poor and surgery is the only option. What if we could fix the heart valves before the baby is ever born? “Science fiction,” you say. Fortunately fetal surgery, the use of surgical treatment on an unborn baby afflicted with certain life-threatening congenital abnormalities, is a procedure that has been used for decades, and the technology to do these procedures is always improving. Fetal surgery attempts to correct problems that are too severe to correct after the baby is born.

There are two main techniques used in fetal surgery. Open fetal surgery used a Cesarean section (hysterotomy) to expose the portion of the baby that requires surgery. After completion of the surgery, the baby is returned to the uterus and the uterus is closed. Sometimes the surgery is scheduled to coincide with the delivery date, and surgery is done before the cord is cut. This way, the baby is sustained by the mother’s placenta and doesn’t need to breathe on his own.

If the baby’s airway it blocked, a procedure called EXIT (ex utero intrapartum treatment) is used. During EXIT procedures, an opening is made in the middle of the anesthetized mother’s belly. The baby is partially delivered through the opening but remains attached by the umbilical cord. Now the surgeon clears the airway so the fetus can breathe. After the procedure, the umbilical cord is cut and clamped, and the infant is fully delivered. EXIT is used to give the surgeon time to perform multiple procedures to clear the baby’s airway, so that once the umbilical cord is cut, the baby can breathe with an unblocked airway.

Fetoscopic surgery makes use of fiber-optic telescopes and specially designed instruments to enter the uterus through small surgical openings to correct congenital malformations without major incisions or removing the fetus from the womb. Fetoscopic surgery is less traumatic and reduces the chances of preterm labor.

Now that we have some clue about fetal surgery, how do we use this to fix heart valves? To fix heart valves, we must replace them with something else. The best alternative would be to grow new heart valves, but these do not grow on trees. What then should we do? The answer is, construct new ones from stem cells.

Tissue engineering uses organic polymers that can be molded into the shape of particular organs and seeded with cells. These polymers are nontoxic and biodegradable. Therefore, once they are seeded with cells, the cells will degrade the polymers and replace them, and grow into the shape originally established by the mold. A special class of fetal stem cells called amniotic fluid stem cells have proven to be especially good at making heart valves and a recent publication shows the feasibility of using laboratory-fashioned heart valves as replacements in fetal sheep.

Weber and colleagues from the Swiss Center for Regenerative Medicine and Clinic for Cardiovascular Surgery, University Hospital Zurich, used stem cells from amniotic fluid to fashion new heart valves. Amniotic fluid comes from a sac that surrounds the embryo and the fetus and is filled with fluid. The embryo and then fetus is suspended in this fluid and the membrane is called the amnion and the fluid is called amniotic fluid.

The Swiss group isolated amniotic fluid cells (AFCs) from pregnant sheep between 122 and 128 days of gestation by means of a technique called “transuterine sonographic sampling.” This technique is rather precise and does not represent a severe risk to the fetus. They then made stented, three-leafed heart valves from a scaffold made from a biodegradable polymer called PGA-P4HB, which stands for poly-glycolic acid dipped in about 1% poly-4-hydroxybutyrate. This material formed a composite matrix that was used to form a heart valve-shaped mold that was then seeded with AFCs. The AFCs grew into the mold, degraded the polymer matrix and assumed the shape of the mold (Weber B., et al., Biomaterials. 2012 Mar 13).

These fabricated heart valves with then implanted into their natural position by means of an in-utero closed-heart hybrid approach. Other sheep fetuses had heart valves implanted that were not seeded with AFCs as a control. 77.8% of the animals implanted with AFC-seeded heart valves survived. Heart functionality tests were measured with echocardiography and angiography, and 1 week after implantation, the fabricated heart valves were completely functional and showed structural integrity (they weren’t falling apart), and also showed no signs of blood clots forming on them (which occurs when heart valves have structural imperfections that allow clotting proteins to stick to them and form clots).

While this experiment represents an interesting approach for fixing fetal hearts, it is still in the experimental stages. Nevertheless, this provides the experimental basis for future human fetal prenatal heart treatments that use completely biodegradable materials seeded with a baby’s own stem cells to make a replacement tissue.

Induced Pluripotent Stem Cells Form Layered Retina-Like Structure in Culture


Embryonic stem cells can form several different types of eye-specific cells. In the early years of the 21st century, reproducible and efficient methods for differentiating embryonic stem cells into lens cells, retinal neurons, and retinal pigment epithelial (RPE) cells were developed (Haruta M., Embryonic stem cells: potential source for ocular repair. Semin Ophthalmol. 2005 Jan-Mar;20(1):17-23).

Other experiments showed that embryonic stem cells could be differentiated into neural progenitor cells (NPCs). These NPCs differentiated in culture and some of them even expressed genes characteristic of developing retinal cells. Although it must be noted that this was uncommon and cells expressing markers of mature photoreceptors were not observed. Implantation of these differentiated NPCs into the retinas of laboratory animals allowed them to survive for at least 16 weeks, migrate over large distances, and form photoreceptor-like cells that made blue-absorbing pigments. These cells also integrated into the host retina (Banin E, Retinal incorporation and differentiation of neural precursors derived from human embryonic stem cells. Steem Cells. 2006 Feb;24(2):246-57).

These early experiments were followed by several others that showed equally remarkable promise. Workers in Takahashi’s laboratory in Kobe, Japan found that embryonic stem cells could form retinal precursors, but that they rarely formed photoreceptors unless they were treated with extracts from embryonic retinas. However in a follow-up paper in 2008, Takahashi, research group found that specific cocktails of small molecules and/or growth factors could push retinal precursors to form photoreceptors (Osakada, et al., Nat Biotechnol. 2008 Feb;26(2):215-24). Kunisada’s lab in Gifu, Japan used various techniques to differentiate embryonic stem cells in culture so that they would form an elaborate retinal-like structure. When this structure was transplanted into the eyes of rodents with inherited eye diseases, these transplanted cells regenerated the ganglion cells in the retina (Aoki H, et al., Graefes Arch Clin Exp Ophthalmol. 2008 Feb;246(2):255-65). Yu’s lab from Seoul National University, Seoul, South Korea made pure RPE cell cultures from embryonic stem cells and then transplanted them into the eyes of rodents with RPE-based retinal degeneration diseases (Park UC, et al., Clin Exp Reprod Med. 2011 Dec;38(4):216-21). The transplanted cells formed RPEs and integrated into the retinas of the laboratory animals. Sophisticated functional assays definitively showed that the RPEs made from embryonic stem cells gobbled up the old segments from photoreceptors and recycled the components back to the photoreceptors (Carr AJ, et al., Mol Vis. 2009;15:283-95).

Using embryonic stem cells to make retina-like structures in culture can provide a model for testing new drugs and procedures to treat degenerative eye diseased such a macular degeneration. Also, such structures might be used to transplant sections of retina into the eyes of individuals where the retina has died off.

With this goal in mind, researchers at the University of Wisconsin-Madison have succeeded in making made early retina structures that contain growing neuroretinal progenitor cells. The novelty in this experiment is that they did it using induced pluripotent stem (iPS) cells that were derived from human blood cells.

In 2011, the laboratory, of David Gamm lab, pediatric ophthalmologist and senior author of the study whose lab is at the Waisman Center, created structures from the most primitive stage of retinal development using embryonic stem cells and iPS cells derived from human skin. These structures generated the major types of retinal cells, including photoreceptors, they did not possess the layered structure found in more mature retina. Clearly something was missing t form a retinal-like structure.

The iPS cells used in this study were made by scientists at a biotechnology company called Cellular Dynamics International (CDI) of Madison, Wisconsin. CDI pioneered the technique to convert blood cells into iPS cells, and they extracted a type of blood cell called a T-lymphocyte from donor samples. These T-lymphocytes were reprogrammed into iPS cells (full disclosure: CDI was founded by UW-Madison stem cell pioneer James Thomson).

With these iPS cells, Gamm and postdoctoral researcher and lead author Joseph Phillips, used their previously-established protocol to grow retina-like tissue from iPS cells. However, this time, about 16% of the initial retinal structures developed distinct layers, which is the structure observed in a mature retina. The outermost layer primarily contained photoreceptors, whereas the middle and inner layers harbored intermediary retinal neurons and ganglion cells, respectively. This particular arrangement of cells is reminiscent of what is found in the back of the eye.

At 72 days, stem cells derived from human blood formed an early retina structure, with specialized cells resembling photoreceptors (red) and ganglion cells (green) located within the outer and inner layers, respectively. Nuclei of cells within the middle layer are shown in blue. These layers are similar to those present during normal human eye development.

These retinal structures also showed proper connections that could allow the cells to communicate information. In the retina, light-sensitive photoreceptor cells along the back wall of the eye produce impulses that are ultimately transmitted through the optic nerve and then to the brain, and this allows. Because these layered retinal structures not only had the proper cell types, but also the proper connections, these findings suggest that it is possible to assemble human retinal cells into the rather complex retinal tissues found in an adult retina. This is extremely stupefying when one considers that these structures all started from a single blood sample.

There are several applications to which these structures might be subjected. They could be used to test drugs and study degenerative diseases of the retina such as retinitis pigmentosa (a major cause of blindness in children and young adults). Also, it might be possible one day to replace multiple layers of the retina in order to help patients with more widespread retinal damage.

Gamm said, “We don’t know how far this technology will take us, but the fact that we are able to grow a rudimentary retina structure from a patient’s blood cells is encouraging, not only because it confirms our earlier work using human skin cells, but also because blood as a starting source is convenient to obtain. This is a solid step forward.” He also added, “We were fortunate that CDI shared an interest in our work. Combining our lab’s expertise with that of CDI was critical to the success of this study.”

This work was published in the March 12, 2012 online issue of Investigative Ophthalmology & Visual Science. The research is supported by the Foundation Fighting Blindness, the National Institutes of Health, the Retina Research Foundation, the UW Institute for Clinical and Translational Research, the UW Eye Research Institute and the E. Matilda Ziegler Foundation for the Blind, Inc.

Fat-Based Mesenchymal Stem Cells Reduce Ischemic Damage to Organs


Ischemia is a term used in medicine to refer to conditions under which organs are deprived of oxygen. Oxygen deprivation causes cells to die and if enough cells die, then the organ is unable to perform its designed function; a condition known as organ failure. Mesenchymal stem cells (MSCs) have been shown in several animal studies to provide significant therapeutic benefit in ischemic organ injuries. Three recent papers have examined the ability of fat-derived MSCs to mitigate ischemic organ damage in lungs, kidneys, and livers. While these studies are in animals, they might provide the foundation for future clinical studies in human patients.

In the first paper (Sun CK, et al., Crit Care Med. 2012 Feb 14), three groups of male rats were either 1) operated on without inducing liver damage; 2) operated on so that the main blood supply to the liver was interrupted for 60 minutes, followed by re-opening the blood supply and treating the rats with fresh culture media that was used to grow the fat-based MSCs; and 3) operated on to cut off the blood supply to the liver for 60 minutes, followed by releasing the blood flow and treatment with fat-derived MSCs at 6 hours and 24 hours after surgery. Three days later, all animals had their livers assayed for damaged, stress and cell death.

In the first group, no sign of liver damage or stress or cell death was observed. In the second group, all the markers for cell death, liver damage and stress were significantly elevated. However in the third group, the markers for cell death, liver damage and stress were significantly lower than those in group two and other markers of liver cell health were increased in the third group relative to the second group.

These results show that fat-derived MSCs preserve liver health and decrease inflammation after ischemic damage to the liver.

The second paper (Furuichi K, et al. Clin Exp Nephrol. 2012 Mar 8), used a similar strategy to examine the ability of fat-derived MSCs to ameliorate kidney function and health after suffering ischemic conditions. Here again, the renal artery to the kidney was clamped for 45 minutes and then injected with either MSCs or buffer at 0, 1, and 2 days after surgery.

The results were a little strange in that the administered MSCs mainly went to the lung. However, those animals that were injected with buffer showed inflammation in the kidney and lots of cell death in the kidney. However those injected with MSCs showed significantly reduced signs of inflammation and greatly reduced amounts of inflammation.

Thus, despite homing to the lung, adipose-derived mesenchymal cells seem to present a reasonable cell-based therapy option for ischemic kidney injury.

Finally, a third paper (Sun CK, et al., J Transl Med. 2011 Jul 22; 9:118), examined the use of fat-derived MSCs to reduce damage during ischemic injury to the lungs. This paper used rats that were divided into three groups. The first group underwent surgery, but no damage was done to the blood supply to the lung. In the second group, the left bronchus of the lung was clamped for 30 minutes, after which the lung was unclamped and the blood allowed to flow for 3 days (known as reperfusion) followed by treatment with fat-derived MSC culture medium. Animals in the third group underwent the same procedure, but were treated with one million and a half fat-derived MSCs at 1, 6, and 24 hours after lung injury. Three days later, animals from all three groups were examined for markers of lung damage and inflammation.

In the first group, the lungs were normal in their function, cell structure, and biochemical markers. No signs of inflammation were observed. The second group, however, had left lung (the one that had been clamped) that worked much more poorly than the right lung. Also, the blood pressure required to push blood through that damaged lobe was much higher in the second group than the other two groups. The more damaged a lung has suffered, the harder it is for the heart to pump blood through it, and the right ventricle much work harder to pump blood through it, which raised the blood pressure in the lung.

The third group showed lungs that worked better and had lower blood pressure than those in the second group. Tissue sections of lungs from group 2 and three animals showed much more damaged in lungs from group two animals than those in group three. Measurement of gene expression in the tissues also showed that lungs from group two animals had much higher levels of genes expressed during inflammation and cell death than those from group three.

This paper presents evidence that fat-derived MSCs might decrease lung damage after ischemic injury.

Trauma to the body from car accidents or work-related injuries can cause organ ischemia. If this damage is significant, acute organ damage can result. Fortunately, fat-derived MSCs are relatively easy to isolate with little additional trauma to the patient. These papers might provide the impetus for future preclinical experimental and, eventually, clinical trials in human patients to alleviate ischemic damage to organs in accident victims.

The Cells=Drugs Argument Has Suffered A Significant Blow


The Regenexx blog site has a fascinating article on tow approaches to reducing transplantation rejection. Osiris Corporation has tried to market a stem product that is a kind of one-size-fits-all stem cell approach for regenerative medicine. This takes mesenchymal stem cells from the bone marrow of young patients and concentrated them in a vial for use. Unfortunately, once these stem cells differentiate into other cell types, they are rejected by the patient’s immune system. While using mesenchymal stem cells from a different person can provide regeneration under particular circumstances, the transplants that use a patient’s own stem cells are always the best from the perspective of the immune system.

A study from Northwestern showed that kidney transplant patients who were also given transplants of bone marrow from the kidney donor did not require any immunosuppressive drugs to prevent the immune system from rejecting their new kidney. This shows that instead of stem cells in a vial (a one-size-fits-all approach to regenerative medicine), an individualized approach seems to be far superior. However, the stem cells = drugs dictum of the FDA argues for the stem cells in a vial approach. Unfortunately, in a Phase III clinical trial, Osiris’ Prochymal product spectacularly failed to provide relief to patients suffering from “Graft versus Host Disease (GVHD). Therefore the stem cells in a vial approach failed, but the individualized worked. This shows that the stem cells = drugs ideology is not one that is tied to reality.

To read Regenexx’s fascinating blog post, go here.

Mesenchymal Stem Cells Can Potentially Treat Non-Union Fractures


Sometimes bone fractures have trouble healing. Such fractures are called “stable non-union fractures,” and they represent major clinical challenges. There are few treatment options for stable non-union fractures, and such conditions represent a major health issue. Fracture treatment options include bone grafting and/or remodeling of the fracture through open reduction and internal fixation (ORIF). In general, ORIF involves the use of plates, screws or even an intramedullary rod to stabilize the bone. Other, less-invasive care options such as treatment with bone morphogenic proteins (BMPs) and other types of bone stimulators are also available.

Can mesenchymal stem cells help such fractures heal better? Centeno and his colleagues at Regenexx conducted their own original research study that shows that some patients probably can be helped by the same sorts of procedures that they use to treat knees. This procedure includes bone marrow aspiration from the crest of the top of the pelvis (the ilium). The mesenchymal stem cells are isolated from the bone marrow and cultured for a few days. Then the expanded and prepared mesenchymal stem cells are applied precisely to the area that needs healing by means of c-Arm fluoroscopy. Sounds good? Yes it does, but to show that it works requires a tried and true clinical study. Centeno’s group has done exactly that, but the number of patients in this study is small. Still this paper represents one of the first examinations of stem cells treatments for stubborn fractures they resist healing.

In this paper, six patients were evaluated. All six had chronic fractures that had not healed (chronic fracture non-unions). There were four women and two men in this experimental group, and they had suffered from these fractures for an average of 8.75 months. The range of the times the patients had lived with these fractures ranged from 4- 18 months, but one patient had lived with their fracture for over 100 months.

All six patient were treated with their own stem cells that were extracted by means of bone marrow aspirations, cultured in the laboratory for 3- 7 passages, and then suspended in phosphate-buffered saline and lysate from peripheral blood platelets. All mesenchymal stem cells were assessed by microscopic examination and flow cytometry to ensure that they expressed the proper surface proteins. Mesenchymal stem cells were then injected percutaneously by means of a sterile trocar, guided by fluoroscopic imaging into the site of the stubborn fracture. To determine if the fractures healed, patients were scanned with X-rays, and computerized tomographic (CT) imaging.

Only five of the patients could be contacted for follow up, but the results are somewhat encouraging. The first patient was a 37-year old smoker (1/4 pack a day) who had suffered with a non-healing fracture for 9 months, but only 2 months after the treatment, was back to “full activities.” An X-ray at 14 months after healing showed excellent healing of the fracture.

The second patient was an 82-year old woman who had suffered from several fractures because of osteoporosis. She had stem cells implanted into her fractured back, and by eight months after the treatment regime, she showed advanced healing of her back fracture. Within four to six weeks after the transplant, the patient walked normally for her age and enjoyed new activities, albeit with age restrictions.

The third patient was a 68-year old woman with a long-time history of multiple sclerosis. She had an 18-month fracture that had not healed in her foot and had to walk with a walking boot immobilizer. Follow-up X-rays showed that after 2 and 6 months she had moderate healing of her fracture and returned to normal activities by 4-6 weeks after the transplant. Unfortunately, she dropped an object on the same foot at 7 months after the procedure and no further follow-up seemed practical.

The fourth patient is a 59 year old woman who had a 40-year history of a traumatic hip fracture and hamstring tear. Unfortunately, her follow up x-rays failed to show any signs of healing.

The fifth patient is a 67-year old man with a 4-month lower leg fracture. He also had type II diabetes mellitus, and coronary artery disease. This patient returned to full walking 4-6 weeks after the procedure. 5 months after the transplant, his x-rays showed signs of healing. No further follow up was possible.

Four of the six patients treated with their own mesenchymal stem cells showed good healing of the fractures that resisted healing through conventional means. The only fracture that showed no signs of healing was a 40-year old fracture that was difficult to immobilize. It is possible that the lack of immobilization caused the bone, which reacts to stress forces, caused this fracture that had adapted to being broken, and could no longer produce signals necessary for repair.

While this study is preliminary, the results support the hypothesis that a patient’s own mesenchymal stem cells are a potential alternative treatment for the treatment of stubborn, fractures that refuse to heal.