P759 - SERINE MODULATES INSULIN RESISTANCE DURING SHORT TERM BED REST

P759

SERINE MODULATES INSULIN RESISTANCE DURING SHORT TERM BED REST

A. Ivetac^1,*, T. Cannito¹, A. Nunnari¹, M. Sturma¹, G. Biolo¹

¹Department of Medical Sciences, University of Trieste, Trieste, Italy

Rationale: Physical inactivity is a well-known contributor to insulin resistance (IR), often associated with altered amino acid (AA) profile. Aim of this study was to assess the potential impact of AAs on IR during inactivity. Are AAs levels potential predictors of IR during muscle unloading?

Methods: Plasmatic AA, glucose and insulin were retrospectively analysed from three different bed rest studies (BR1, BR2, BR3) involving 26 young healthy males. Since AAs were analysed on different days, we imputed all missing values with MICE, which allowed us to evaluate trends of plasmatic AAs in relation with IR (HOMA IR) during 9 days of inactivity. A GLMM was fitted to examine the effect of selected plasmatic AAs (predictors) on HOMA IR (outcome variable). Results of GLMM were further validated with data from BR1 and BR2 (19 subjects), in which AAs were analysed on day 1,5 and 9. 

Results: Serine exhibited a sig. negative fixed effect on HOMA IR [-0,015] (p = 0,006), while HOMA-IR had no sig. effect on serine(p=0,507), suggesting a unidirectional relationship. Further analysed data from BR1 and BR2 confirmed the inverse effect: serine levels sig. increased during the initial days (+13%), followed by a sig. drop from 5^th to the 9^th day (-6,5%). When serine was available, HOMA IR was not sig. affected. When serine availability dropped, HOMA IR continued to rise, reaching a sig. difference from baseline values to 9^th day of BR (+27%). Furthermore, simple linear regression was conducted to examine the relationship between serine (predictor) and HOMA IR (outcome). The model was sig. when evaluating absolute values from baseline to the 9^th day (p=0,021; r²=0,09), from 5^th to 9^th day (p=0,008; r²=0,180) and marginally sig. from baseline to 5^th day of BR (p=0,051; r²=0,101).

Conclusion: Our findings indicate that serine can have an inverse impact on IR and not vice versa. Upholding serine levels during short term BR could have a protective role against IR. 

Disclosure of Interest: None declared