RESUMO
Atonal Homolog 8 (Atoh8) belongs to a large superfamily of transcriptional regulators called basic helix-loop-helix (bHLH) transcription factors. Atoh8 (murine homolog "Math6") has been shown to be involved in organogenesis during murine embryonic development. We have previously identified the expression of Atoh8 during skeletal myogenesis in chicken where we described its involvement in hypaxial myotome formation suggesting a regulatory role of Atoh8 in skeletal muscle development. Within the current study, we analyzed the effect of the loss of function of Atoh8 in murine primary myoblasts and during differentiation of pluripotent stem cells into myotubes, and the effect of its gain of function in C2C12 cells. Based on the observed results, we conclude that Atoh8 regulates myoblast proliferation via modulating myostatin signaling. Further, our data revealed a reduced muscle mass, strength and fiber size with significant changes to the muscle fiber type suggesting atrophy in skeletal muscle of Atoh8 mutants. We further report that Atoh8 knockout mice suffer from a condition similar to ambient hypoxia which may be the primary cause of the phenotype. Altogether, this study shows the significance of Atoh8 not only in myogenesis but also in the maintenance of skeletal muscle.
RESUMO
BACKGROUND: Studies focusing on self-perception of nutritional status in older hospitalized patients are lacking. We aimed to examine the self-perception of body weight and nutritional status among older hospitalized patients compared to their actual body weight and nutritional status based on medical assessment. MATERIALS AND METHODS: This observational cross-sectional study investigated 197 older participants (mean age 82.2±6.8 years, 61% women) who were consecutively admitted to the geriatric acute care ward. Body weight status and nutritional status were assessed using WHO-BMI classification and Mini Nutritional Assessment-Short Form (MNA-SF), respectively. Self-perceived body weight status and nutritional status were assessed with a standardized questionnaire. A follow-up was performed with a short telephone interview after three months. RESULTS: According to MNA-SF, 49% and 35% were at risk of malnutrition and malnourished, respectively. There was no agreement between self-perceived nutritional status and objective nutritional status according to MNA-SF (Kappa: 0.06). A slight agreement was found between subjective body weight status and objective body weight status according to WHO-BMI classification (Kappa: 0.19). A total of 184 patients completed the 3 months follow-up and additional 9 patients died during this time, of which 7 and 2 were malnourished and at risk of malnutrition according to MNA-SF, respectively. Of those who were malnourished and at risk of malnutrition based on MNA-SF and died during follow-up, 67.7% did not realize their malnutrition. Compared to the patients with normal nutritional status during hospitalization, malnourished patients based on MNA-SF had higher rates of unplanned hospital readmission and further weight loss and more often reported health deterioration and experienced death within three months after discharge. CONCLUSION: No agreement between self-perceived nutritional status and objective nutritional status among older hospitalized patients was found. Our study highlights the need to raise knowledge about the issue of malnutrition and increase awareness of health risks associated with malnutrition among older hospitalized patients.
