Human Umbilical Cord Stem Cells Prevent Liver Failure in Mice

Acute liver failure results from massive liver damage over a short period of time. Viral infections (hepatitis B virus), drugs (acetaminophen, halothane), sepsis, Wilson’s disease, or autoimmune hepatitis can all cause acute liver failure, but acute liver failure can be life-threatening. Remember, the liver makes the vast majority of blood proteins such as clotting factors or albumin, and without a functioning liver, multi-organ failure ensues.

Liver transplantation can offer effective treatment of acute liver failure, except that there is a global shortage of available livers. The wife of my colleague at Spring Arbor University waited years and years for a liver until a liver was given to her as the result of a dying declaration. THe need is substantial and the supply is miniscule.

Several experiments have demonstrated that the transplantation of mesenchymal stem cells (MSCs) can treat acute liver failure. Human umbilical cord MSCs (hUCMSCs) can be differentiated into cells that closely resemble liver cells (known as hepatocytes) and these i-Heps, as they are called, display many liver-specific functions (secretion of albumin, storage of glycogen, see Campard et al., Gastroenterology 134 2008: 833-848). Likewise, UBMSCs secrete a host of interesting pro-regenerative molecules that seem to aid in liver recovery, regeneration, and healing when implanted into a damaged liver (see Banas et al., J Gastroenterol Hepatol 24 2009: 70-77; van Poll, et al., Hepatology 47 2008: 1634-1643; Moslem, et al., Cell Transplant 22(10) 2013: 1785-99).

To this end, scientists from the Chinese Academy of Sciences in Shenzhen, China have done an interesting side-by-side comparison of the ability of i-Heps and undifferentiated UCMSCs to mitigate acute liver damage in a mouse model.

Ruiping Zhou and Zhuokun Li in the laboratory of Zhi-Ying Chen and their colleagues injected a mixture of D-Galactosamine and a bacterial compound called LPS (lipopolysaccharide) into the bellies of NOD/SCID mice (non-obese diabetic, severe combined immunodeficiency) to induce acute liver damage. Half of the mice injected with this concoction died of acute liver failure, and autopsies of the mice in these experiments showed that half of the liver cells in their livers had been burned out. A control group was injected with salt solutions and showed no such liver damage.

Of these mice, some of the were injected with either two million UBMSCs or two million i-Heps, six hours after the induction of acute liver damage. The cells were given intravenously, in the tail vein.

Interestingly, both groups of mice – those that had received the UBMSCs and those that had received the i-Heps – showed improved survival and improved liver function as ascertained by several liver function tests. Liver biopsies revealed lower levels of cell death within the liver in both cases. Also when the liver is damaged, there are several blood tests that can reveal the presence of liver damage and indicate the degree of liver damage. In all cases where the D-Galactosamine and LPS were administered, the levels of these liver enzymes increased the first after their administration, but in those animals that received either UBMSCs or i-Heps, the markers of liver damage neither climbed as high, nor did they stay high as long, indicating the damage to the liver was mitigated by the infused stem cells.

Liver biopsies of the laboratory animals further confirmed the decreased levels of liver scarring in those animals that had received the stem cells with the D-galactosamine and LPS. Also the levels of cell division, indicative of healing, were increased in the stem cell-treated animals. Two weeks after the initial liver damage, large areas of the liver were observed that showed the signs of cell division, which indicates the presence of active liver repair activities at work in the stem cell-treated animals. Mice not treated with stem cells showed extensive liver damage with little signs of healing if they survived at all.

This interesting study shows that both hUCMSCs and hUCMSC-derived -i-Heps exhibited similar therapeutic effects for mouse acute liver failure. Also, when injected into the tail vein, the stem cells were able to home to the damaged liver and set up shop there. The liver regeneration in both cases seemed to be due to the stimulation of resident liver cells rather substantial contributions from the infused stem cells.

What does this mean for human regenerative medicine? Umbilical cord MSCs are probably a good source of material to treat liver failure. However, such cells will need to be matched to the tissue type of the patient. Secondly, a point emphasized in this paper is that MSCs should not be overly manipulated before they are used because some experiments with MSCs have shown that if these cells are grown in long-term culture, they can undergo malignant transformation (see Rosland, et al., Cancer Res 69 2009: 5331-5339).

Thus beefing the number of cells up for therapeutic purposes to treat a human, which is larger than a mouse, might represent a challenge. However, it is possible to expand MSCs in culture without transforming them into cancer cells, as long as it is done for a short period of time. Finally, MSCs represent an excellent alternative for the shortage of livers, since they can stimulate the liver’s internal healing systems to heal themselves on a short-term basis without the need for a liver transplantation. This sounds like a win-win situation. Of course more work must be done first. Preclinical studies like this must be expanded and then larger animals will need to be used as well before human clinical trials can be planned.

Transplanted Liver Cells do Better When Co-Cultured with Mesenchymal Stem Cells

Implanting frozen liver cells is a relatively new procedure that has, reportedly, been used to treat very young patients with liver problems. Thawing frozen liver cells, however, tends to cause a fraction of the cells to die off and other damaged cells show poor function.

To ameliorate this problem, researchers at Kings College Hospital, London have used mesenchymal stem cells from fat or umbilical cord to improve the viability and function of frozen liver cells.

Emer Fitzpatrick and her colleagues at Kings College Hospital reasoned that mesenchymal stem cells and the multitudes of healing molecules that these cells secrete should be able to “lend proregenerative characteristics to liver cells.”

Thus by co-culturing thawed liver cells with mesenchymal stem cells from fat or umbilical cord, Fitzpatrick and others demonstrated that the rate of cell survival of the liver cells and their functionality increased in comparison with liver cells grown on their own.

Fitzpatrick hopes that such a co-culture technique might improve the clinical usefulness of frozen liver cells for transplantation.

Human Umbilical Cord Mesenchymal Stem Cells and Rheumatoid Arthritis

A collaborative study between physicians at the Hospital of Chinese People’s Liberation Army and the University of Oklahoma Health Sciences Center has examined the efficacy of umbilical cord mesenchymal stem cell treatments in combination with drugs in patients with active rheumatoid arthritis (RA).

RA may exist in 0.5-1.0% of the general population. In 2005, an estimated 1.5 million US adults aged ≥ 18 (0.6%) had RA. RA is characterized by chronic inflammation of the joints that causes cartilage and bone damage and deformity. It occurs in women two to three times more often than men.

Treatment of RA requires the administration of disease-modifying antirheumatic drugs (DMARDs), Unfortunately, these drugs have sizable side effects, and less debilitating treatments would be a welcome addition to the treatment options for RA patients.

A paper by Liming Wang and colleagues that was published in Stem Cells and Development examines the efficacy of combining DMARDs with infusions of umbilical cord mesenchymal stem cells (MSCs). Since MSCs have the ability to suppress an overactive immune response, such treatments might provide relief from the symptoms of RA and decrease the dependence on DMARDs.

In this study, Wang and others enrolled 172 RA patients and divided them into two groups: 36 of them were treated with DMARDs alone and 136 were treated with DMARDs plus umbilical cord MSCs (UC-MSCs). Of these 136 patients, 76 were treated for 3 months, 45 for 6 months, and 15 for 8 months. Each of these groups consisted of patients who could and who could not tolerate DMARDs. All patients in the second group received 4 x 10[7] UC-MSCs in 40 milliliters of liquid, but the first group received stem cell “solvent” (whatever that is) without UC-MSCs.

The results clearly showed that UC-MSCs treatments are safe. Patients blood work-ups before and after treatment show no significant differences. Secondly, the DMARD-only group did not show any improvements, but they did not get worse either. The DMARD + UC-MSC group showed quantifiable improvements. These patients reported feeling better in health assessment questionnaires, their serum levels of C-reactive protein and rheumatoid factor went down and their numbers of regulatory T-cells went up. The joint evaluations of these patients also improved (the so-called DAS28 score). All of these are measures of the severity of RA, and in the DMARD + UC-MSC groups, all the these markers improved.

Other markers of RA severity such as IL-6 and TNF-alpha also decreased in the DMARD + UC-MSC patients.

From these data, Wang and others conclude that “UC-MSCs are suitable pllications in the clinic and provide an additional choice to many RA patients.”

The data in this paper are rather clear. The benefits of a single UC-MSC treatment are significant. For this reason, umbilical cord MSCs should be regarded as a potential adjuvant treatment for RA patients.

Big Strides in Stem Cell Treatments for Neonatal Lung Diseases

Bernard Thébaud works at the Ottawa Hospital Research Institute (OHRI) and Children’s Hospital of Eastern Ontario (CHEO), and is also a member of the Ottawa Stem Cell Initiative. Dr. Thébaud has proposed a new therapy that utilizes umbilical cord stem cells to treat a lung disease called bronchopulmonary dysplasia (BPD), which was previously thought to be untreatable.

Thébaud described BPD in this way: “BPD is a lung disease described 45 years ago in which we have made zero progress. And now, with these cord-derived stem cells there is a true potential for a major breakthrough. I am confident that we have the talent and the tools here at CHEO and OHRI to find a treatment for BPD. These findings published today are helping us get there.”

Every year, BPD affects ~10,000 premature newborns in Canada and the US. The lungs of infants with BPD are not developed enough to function properly, and consequently the baby has to be placed on a ventilator in order to receive sufficient quantities of oxygen. Mechanical respirators, however, are very hard on such young, friable lungs, and the lungs then to fray and this prevents them from developing properly. The longer the baby stays in the neonatal intensive care unit, the greater the degree of multiorgan damage (retina, kidneys, and the brain). Therefore, the baby needs oxygen to survive, but the very act of giving them oxygen eventually hastens their death.

Thébaud’s research team used new-born rats that were given oxygen soon after their premature birth. Some were given stem cell treatments and others were not. These experiments produced five new findings:

1) Mesenchymal stem cells (MSCs) from human umbilical cord can protect the lungs when injected into the lungs as the animals were put on oxygen.
2) MSCs had a tendency to stimulate repair of the damaged lungs when injected two weeks after the animals were put on oxygen.
3) The medium in which the MSCs were grown (conditioned medium) was injected into the lungs instead of the cells, this medium had the same reparative and protective effects as the cells themselves.  This suggests that it is the cocktail of growth factors and other supportive molecules secreted by the MSCs that provide their healing properties.  Such a mechanism, in which the cells secrete molecules that affect nearby cells and tissue, is known as a “paracrine” mechanism.
4) When examined six months after treatment (the equivalent of 40 human years), the treated animals had better exercise performance and more normal lung structure.
5) MSC administration did not adversely affect the long-term health of the laboratory animals. None of the MSC-treated animals had any tumors and MSCs given to control animals that did not have BPD were also normal six months later.

Thébaud would like to conduct a pilot clinical (Phase I) study within two years with around 20 human patients in order to determine if this treatment is feasible and safe. If the treatment turns out to be safe, Thébaud would like to initiate a randomized controlled (Phase II) clinical trial.

See Maria Pierro et al., “Short-term, long-term and paracrine effect of human umbilical cord-derived stem cells in lung injury prevention and repair in experimental bronchopulmonary dysplasia,” Thorax 2012: DOI:10.1136/thoraxjnl-2012-202323.