Obesity leads to sarcopenia and poor physical function with aging. Evidence in animals and in middle-age humans suggests that the pituitary hormone oxytocin reduces appetite, promotes weight loss, and improves glucose tolerance while preserving lean muscle mass. We studied oxytocin’s effect on body mass index (BMI), glucose tolerance, muscle mass, and physical function in an older adult population with sarcopenic obesity. Twenty-one older (≥60 yrs), obese (30-43 kg/m2), sedentary (<2 exercise/week) adults with slow gait (<1 m/sec) were randomized to either intranasal oxytocin (24 IU QID) or placebo for 8 wks. Those with diabetes, mod-severe chronic diseases, and cognitive impairment (Mini-Cog <3) were excluded. Pre and post BMI, oral glucose tolerance test (OGTT), Hemoglobin A1c (HbA1c), physical function (short physical performance battery [SPPB]), and whole body lean and fat mass (via DXA) were assessed. Generalized linear mixed effects models were used to evaluate the effect of oxytocin on these measures. Age was 67.5 ±5.4 yrs, 71% were female, BMI was 36.0 ±3.6 kg/m2, fasting plasma glucose (FPG) was 92.0 ±8.9 mg/dL, HbA1c was 5.7 ±0.4%, 2-hour OGTT glucose was 140.8 ±4.1 mg/dL, SPPB was 9.2 ±1.9, fat mass was 45429.1 ±7037.4 g, and lean mass was 49892.4 ±10470.9 g. At 8 wks, total lean mass increased significantly (2,250 g) in the oxytocin group (pre- vs. post-treatment difference of -690.5 g in placebo and +1,559.5 g in the oxytocin group, p<0.01). Oxytocin did not lead to significant changes in BMI, FPG, HbA1c, 2-hour OGTT glucose, fat mass or SPPB.
In conclusion, this preliminary data suggests that oxytocin leads to improvement in whole body lean mass. Future studies are needed in a larger population to determine whether older adults with sarcopenic obesity may benefit from treatment with oxytocin to improve lean muscle mass. Further work is needed to determine whether these improvements ultimately lead to improved physical function and other parameters of healthspan with aging.
S.E. Espinoza: None. J. Lee: None. C. Wang: None. D.J. MacCarthy: None. V. Ganapathy: None. C. Pascucci: None. N. Musi: None.
Claude D. Pepper Older Americans Independence Centers (University of Texas Health Science Center at San Antonio; University of Texas Medical Branch Galveston); Clinical Translational Science Award Programs (University of Texas Health Science Center at San Antonio; University of Texas Medical Branch Galveston); University of Texas Health Science Center at Houston