8488 Sex-Specific Differences in an Alstrom Syndrome Mouse Model

Abstract Disclosure: Y. Carcamo-Bahena: None. J. Youn: None. E. Lartigue: None. S. Sisley: None. Background: Alström syndrome is a monogenic autosomal recessive disorder caused by loss of the ALMS1 gene that affects 1 in 1 million. Loss of a functional ALMS1 protein leads to global disorganization of microtubules. Patients are affected by progressive vision and hearing loss and are at risk of developing obesity and type 2 diabetes. Aside from reproductive system anomalies, no clinical reports have identified sex-specific difference in patients with Alström syndrome. Methods: Male and female Alms1tvrm[1]02/tvrm[1]02 (null), Alms1tvrm[1]02/+ (heterozygous) and wildtype littermate mice were weaned onto standard chow diet. At 16 weeks of age, they were changed to a 45% high fat diet (HFD). Weekly body weights were collected and intraperitoneal glucose tolerance tests (GTTs, 1.5 g/kg D20W) were performed at three different time points (11, 16, 25 weeks of age). Results:Alms1 null mice were heavier than wildtype and heterozygous mice on standard chow diet. In males, significant changes in weight gain in null mice occurred by 10 weeks compared to wildtype and heterozygous mice (p<0.05). In females, compared to null, this change was observed by 13 weeks (p<0.05). Although female mice are typically protected from diet-induced obesity, the null females weighed the same as the null males (65.0 ± 2.0 vs 67.7 ± 2.8 g) after 9 weeks on HFD. We observed sex and diet specific differences in GTT outcomes. On chow diet, Alms1 deficiency did not affect glucose levels during a GTT in female mice. However, after 9 weeks of HFD (25 weeks of age), baseline fasting glucose levels were higher in the null females compared to wildtype (p<0.05) and heterozygotes (p<0.01). Additionally, the GTT curve was monophasic, indicating onset of diabetes whereas wildtype and heterozygotes (p<0.0001) had normal curves. Null male mice showed an impaired glucose response at 11 weeks of age on chow diet compared to wildtype and heterozygous males (p<0.001) and by 16 weeks, the GTT glucose curve for Alms1 null mice was monophasic. After 9 weeks of HFD, no differences were observed in glucose levels during a GTT. Conclusions: We observed sex-specific differences in this Alms1 null mouse model related to body weight and glucose tolerance with male null mice exhibiting earlier obesity and impaired glucose tolerance and female mice showing more pronounced effects on a HFD. Future research should investigate if these sex-specific effects alter responses to dietary or pharmaceutical interventions. Presentation: 6/1/2024