Transplantation of PSC-derived myogenic progenitors counteracts disease phenotypes in FSHD mice.

Facioscapulohumeral muscular dystrophy (FSHD) is a genetically dominant progressive myopathy caused by improper silencing of the DUX4 gene, leading to fibrosis, muscle atrophy, and fatty replacement. Approaches focused on muscle regeneration through the delivery of stem cells represent an attractive therapeutic option for muscular dystrophies. To investigate the potential for cell transplantation in FSHD, we have used the doxycycline-regulated iDUX4pA-HSA mouse model in which low-level DUX4 can be induced in skeletal muscle. We find that mouse pluripotent stem cell (PSC)-derived myogenic progenitors engraft in muscle actively undergoing DUX4-mediated degeneration. Donor-derived muscle tissue displayed reduced fibrosis and importantly, engrafted muscles showed improved contractile specific force compared to non-transplanted controls. These data demonstrate the feasibility of replacement of diseased muscle with PSC-derived myogenic progenitors in a mouse model for FSHD, and highlight the potential for the clinical benefit of such a cell therapy approach.

Should hepatitis B vaccine be used for infants?

Chronic hepatitis B virus infection causes nearly all the deaths from this virus. As the initial infection occurs without symptoms and decades prior to the onset of cirrhosis and liver cancer, these consequences are rarely recognized as being caused by the virus. Consequently, its public health importance is under-recognized. Safe and effective vaccines have now been available for over 20 years. Concerns have been raised regarding the mercury preservative in vaccines leading to potential toxicity. But the evidence to date does not support any association of hepatitis B vaccine with serious adverse consequences. Protecting infants through immunization is the most effective control strategy. By 2005, over 80% of countries had implemented routine infant immunization. In countries with relatively low rates of hepatitis B virus infection, some have argued to defer immunization until later life. However, these arguments focus on the more visible acute infection. The possible future cost from a single infant infection argues for universal infant hepatitis B immunization--given the very high costs of treating its consequences (e.g., liver transplant) and the very low price of the vaccine.