12-week Dolutegravir treatment marginally reduces energy expenditure but does not increase body weight or alter vascular function in a murine model of Human Immunodeficiency Virus infection

Abstract

Combination antiretroviral therapy (cART) has markedly increased life expectancy in people with HIV (PWH) but has also resulted in an increased prevalence of cardiometabolic disorders, whose etiopathology remains ill-defined. Notably, the respective contribution of cART and HIV-derived proteins to obesity and vascular alterations remain poorly understood. Therefore, we investigated the individual and combined effects of HIV-proteins and of the integrase strand transfer inhibitor Dolutegravir (DTG) on body composition and vascular reactivity. Male wildtype (WT) and HIV transgenic (Tg26) mice, received DTG or vehicle for 12 weeks. Viral proteins expression in Tg26 mice lowered fat mass, increased heat production, and induced a 2-fold increase in brown adipose tissue (BAT) uncoupling protein 1 (UCP1) expression. DTG increased the expression of markers of adipogenesis in adipocytes in culture, but also reduced heat production and BAT UCP1 and UCP3 expression in Tg26 mice. DTG increased food intake, fat percentage and protected from lean mass reduction in Tg26 mice only. However, DTG did not increase body weight in either WT or Tg26 mice. Viral protein expression reduced acetylcholine (endothelium)-mediated relaxation by 14% in mesenteric arteries preconstricted with phenylephrine. However, DTG did not impair nor improve endothelium-dependent relaxation. Together, these data indicate that DTG's effects on food intake, adipogenesis and energy expenditure are insufficient to increase body weight, even in the presence of HIV-proteins, suggesting that body weight gain in PWH involves additional factors likely including other cART components and pre-existing comorbidities. Moreover, these data rule out DTG as a source of vascular disorders in PWH.

Keywords: Combination antiretroviral therapy; Endothelial function; HIV; Integrase inhibitor; Obesity.

Figure 1:. Tg26 reduces adiposity while DTG treatment increases fat percentage in Tg26 mice only.

Body weight changes throughout the 12-week treatment period in WT mice (A) and Tg26 mice (B) treated with vehicle (non-infused chow) or Dolutegravir infused chow (DTG, 7mg/kg). NMR measurement of fat (C,D) and lean mass percentage (E,F). Measurement of food intake (G,H) at the end of the 12-week treatment period. Data are mean±sem. N=4-7. *P<0.05, **P<0.01.

Figure 2:. DTG treatment decreases brown adipose tissue in WT and Tg26 mice.

Tissue to body weight ratios (mg tissue/gram of body weight) in WT and Tg26 mice treated with either vehicle or DTG for 12 weeks. Visceral adipose tissue (VAT, A), Subcutaneous adipose tissue (SUBQ, B), brown adipose tissue (BAT, C), heart (D), and spleen (E). Data are presented as mean ± SEM. n=4-10. **P<0.01, ***P<0.001, ****P<0.0001.

Figure 3:. DTG treatment increases Ki67 and adiponectin in VAT.

RT-qPCR quantification of leptin (A, B), Ki67 (C, D), and adiponectin (E, F) in primary adipocytes isolated from VAT (A, C, E) and SUBQ (B, D, F) treated with vehicle or DTG (0.5 mg/mL) for 24 hours. Data are presented as mean ± SEM. n=3. *P<0.05, **P<0.01.

Figure 4:. DTG marginally decreased active (night) RER and heat production in WT and Tg26 mice.

Indirect calorimetry measurement of respiratory exchange ratio (RER, A-D) and heat production (E-H) in WT and Tg26 mice treated with vehicle or DTG for 12 weeks. Data are presented as mean ± SEM. n=4-7. *P<0.05, **P<0.01.

Figure 5:. DTG treatment decreases BAT UCP1 and UCP3 levels in Tg26 mice.

RT-qPCR quantification of thermogenic UCP1 (A) and UCP3 (3) in BAT. Data are presented as mean ± SEM. n=4-6. *P<0.05, **P<0.01.

Figure 6:. Tg26 impairs endothelial function, but DTG treatment does not affect vascular reactivity.

Vascular relaxation to acetylcholine (ACh, endothelial dependent relaxation, A, B), and sodium nitroprusside (SNP, endothelium independent relaxation, C, D) measured in 2^nd order mesenteric arteries (preconstricted with phenylephrine, 10 μmol/L) from WT and Tg26 mice treated with vehicle or DTG. Vascular constriction to phenylephrine (Phe, adrenergic contractility, E, F) and potassium chloride (KCl, contractile response to depolarization, G, H) measured in 2^nd order mesenteric arteries. Pulse wave velocity measured in WT and Tg26 mice (I). Data are presented as mean ± SEM, n=4-6. *P<0.05.

Figure 7:. Acute DTG treatment does not affect vascular reactivity.

Relaxation to acetylcholine (ACh, A) and sodium nitroprusside (SNP, B) in WT aortic rings exposed to DTG (0.5mg/mL) or vehicle for 14 hour. Data are presented as mean ± SEM, n=4.