OBESITY-INDUCED HYPERTENSION: WHAT DOES THE BRAIN HAVE TO DO WITH IT?

Obesity burdens have been around the globe. The increased intake of highly caloric food and reduced physical activity have contributed to weight gain in recent decades. One of the possible consequences of obesity is an increase in arterial pressure. In a series of studies conducted in the past years in our laboratory, we observed that adult male and female rats fed for six weeks a high-fat diet (HFD; 45% calories from fat) had an increased body mass and adiposity, dyslipidemia, hyperinsulinemia and hyperleptinemia, like humans. Adult male rats had an increase in arterial pressure that started around three weeks after introducing the HFD and lasted for the whole experimental period. Obesity-induced hypertension seems to involve an increased hypertensive axis of the central renin-angiotensin system in the forebrain and the hindbrain. Neuroinflammation appears in brain areas that are involved in cardiovascular regulation. Surprisingly, there was no change in arterial pressure in female adult rats during the six weeks of the HFD food regimen. The absence of hypertension may be related to the protective effect of estrogen. However, there was an increase in heart rate, like male rats. Epigenetic studies were conducted in the juvenile male (P35) offspring of HFD-fed dams. The offspring were fed from P21 to P35 with a standard diet (SD; 11% calories from fat). They presented an increase in adiposity despite no change in body weight at this age. Sympatho-excitation and a more significant modulation of sympathetic activity to the blood vessels were also observed. Overall, brain mechanisms are pivotal for the changes in arterial pressure/sympathetic activity in HFD-fed adult male rats and in male juvenile offspring of HFD-fed dams. Sexual dimorphism in the cardiovascular changes induced by HFD might have a role.

This work was supported by Conselho Nac. Des. Cient. Tecnologico (CNPq # 308099/2017-6 and 317348/2021-3), by the FAPESP (15/23467-7) and by CAPES PrINT-UNESP.