Tbx1 regulates inherited metabolic and myogenic abilities of progenitor cells derived from slow- and fast-type muscle.

Skeletal muscle is divided into slow- and fast-type muscles, which possess distinct contractile and metabolic properties. Myogenic progenitors associated with each muscle fiber type are known to intrinsically commit to specific muscle fiber lineage during embryonic development. However, it is still unclear whether the functionality of postnatal adult myogenic cells is attributable to the muscle fiber in which they reside, and whether the characteristics of myogenic cells derived from slow- and fast-type fibers can be distinguished at the genetic level. In this study, we isolated adult satellite cells from slow- and fast-type muscle individually and observed that satellite cells from each type of muscle generated myotubes expressing myosin heavy chain isoforms similar to their original muscle, and showed different metabolic features. Notably, we discovered that slow muscle-derived cells had low potential to differentiate but high potential to self-renew compared with fast muscle-derived cells. Additionally, cell transplantation experiments of slow muscle-derived cells into fast-type muscle revealed that slow muscle-derived cells could better contribute to myofiber formation and satellite cell constitution than fast muscle-derived cells, suggesting that the recipient muscle fiber type may not affect the predetermined abilities of myogenic cells. Gene expression analyses identified T-box transcriptional factor Tbx1 as a highly expressed gene in fast muscle-derived myoblasts. Gain- and loss-of-function experiments revealed that Tbx1 modulated muscle fiber types and oxidative metabolism in myotubes, and that Tbx1 stimulated myoblast differentiation, but did not regulate myogenic cell self-renewal. Our data suggest that metabolic and myogenic properties of myogenic progenitor cells vary depending on the type of muscle from which they originate, and that Tbx1 expression partially explains the functional differences of myogenic cells derived from fast-type and slow-type muscles.

Immunization of mice with LRP4 induces myasthenia similar to MuSK-associated myasthenia gravis.

Since the first report of experimental animal models of myasthenia gravis (MG) with autoantibodies against low-density lipoprotein receptor-related protein 4 (LRP4), there have not been any major reports replicating the pathogenicity of anti-LRP4 antibodies (Abs). Recent clinical studies have cast doubt on the specificity and pathogenicity of anti-LRP4 antibodies for MG, highlighting the need for further research. In this study, we purified antigens corresponding to the extracellular region of human LRP4 stably expressed with chaperones in 293 cells and used these antigens to immunize female A/J mice. Immunization with LRP4 protein caused mice to develop myasthenia having similar electrophysiological and histological features as are observed in MG patients with circulating Abs against muscle-specific kinase (MuSK). Our results clearly demonstrate that active immunization of mice with LRP4 proteins causes myasthenia similar to the MG induced by anti-MuSK Abs. Further experimental and clinical studies are required to prove the pathogenicity of anti-LRP4 Abs in MG patients.

Going back to home to die: does it make a difference to patient survival?

BACKGROUND: Many patients wish to stay at home during the terminal stage of cancer. However, there is concern that medical care provided at home may negatively affect survival. This study therefore explored whether the survival duration differed between cancer patients who received inpatient care and those who received home care. METHODS: We retrospectively investigated the place of care/death and survival duration of 190 cancer patients after their referral to a palliative care consultation team in a Japanese general hospital between 2007 and 2012. The patients were classified into a hospital care group consisting of those who received palliative care in the hospital until death, and a home care group including patients who received palliative care at home from doctors in collaboration with the palliative care consultation team. Details of the place of care, survival duration, and patient characteristics (primary site, gender, age, history of chemotherapy, and performance status) were obtained from electronic medical records, and analyzed after propensity score matching in the place of care. RESULTS: Median survival adjusted for propensity score was significantly longer in the home care group (67.0 days, n = 69) than in the hospital care group (33.0 days, n = 69; P = 0.0013). Cox's proportional hazard analysis revealed that the place of care was a significant factor for survival following adjustment for covariates including performance status. CONCLUSIONS: This study suggests that the general concern that home care shortens the survival duration of patients is not based on evidence. A cohort study including more known prognostic factors is necessary to confirm the results.

Evaluation of A Novel Information-Sharing Instrument for Home-Based Palliative Care: A Feasibility Study.

AIM: To examine the feasibility and usefulness of a novel region-based pathway: the Regional Referral Clinical Pathway for Home-Based Palliative Care. METHOD: This was a feasibility study to evaluate the frequency of variances and the perceived usefulness of pathway using in-depth interviews. All patients with cancer referred to the palliative care team between 2011 and 2013 and received home care services were enrolled. RESULT: A total of 44 patients were analyzed, and pathway was completed in all the patients. The target outcome was achieved in 61.4% while some variances occurred in 54.5%. Nine categories were identified as the usefulness of the pathway, such as reviewing and sharing information and promoting communication, education, motivation, and relationships. CONCLUSION: This novel pathway is feasible and seems to be useful.