Neurohumoral stimulation in type-2-diabetes as an emerging disease concept

Abstract

Neurohumoral stimulation comprising both autonomic-nervous-system dysfunction and activation of hormonal systems including the renin-angiotensin-aldosterone system (RAAS) was found to be associated with Type-2-diabetes (T2D). Therapeutic strategies such as RAAS interference proved to be beneficial in both T2D treatment and prevention. In addition to an activated RAAS, hyperleptinemia in obesity, hyperinsulinemia in conditions of peripheral insulin resistance and overall oxidative stress in T2D represent known activators of the sympathetic component of the autonomic nervous system. Here, we hypothesize that sympathetic activation may cause peripheral insulin resistance defined as partial blocking of insulin effects on glucose uptake. Resulting hyperinsulinemia or hyperglycemia-related oxidative stress may further aggravate sympatho-excitation. This notion leads to a secondary hypothesis: sympathetic activation worsens from obesity towards insulin resistance, and further towards T2D. In this review, existing evidence relating to neurohumoral stimulation in T2D and consequences thereof, such as oxidative stress and inflammation, are discussed. The aim of this review is to provide a rationale for therapies, which are able to intercept neuroendocrine pathways in T2D and precursor states such as obesity.

Figure 1

Relationships between known risk factors for T2D, neurohumoral factors and consequences thereof including oxidative stress and inflammatory response leading to peripheral IR and T2D. Blue arrows represent stimulation pathways, green arrow represents inhibition.

Figure 2

Suggested therapeutic interventions with regard to the framework of T2D risk factors and neurohumoral factors given in Figure 1. Solid lines across empty arrows signify blocked pathways; dotted lines across solid arrows represent attenuated pathways.