Coadjuvants in the Diabetic Complications: Nutraceuticals and Drugs with Pleiotropic Effects

Because diabetes mellitus (DM) is a multifactorial metabolic disease, its prevention and treatment has been a constant challenge for basic and clinical investigators focused on translating their discoveries into clinical treatment of this complex disorder. In this review, we highlight recent experimental and clinical evidences of potential coadjuvants in the management of DM, such as polyphenols (quercetin, resveratrol and silymarin), cultured probiotic microorganisms and drugs acting through direct/indirect or pleiotropic effects on glycemic control in DM. Among several options, we highlight new promising therapeutic coadjuvants, including chemical scavengers, the probiotic kefir and the phosphodiesterase 5 inhibitors, which besides the reduction of hyperglycemia and ameliorate insulin resistance, they reduce oxidative stress and improve endothelial dysfunction in the systemic vascular circulation. In the near future, experimental studies are expected to clear the intracellular pathways involving coadjuvants. The design of clinical trials may also contribute to new strategies with coadjuvants against the harmful effects of diabetic complications.

Sildenafil prevents renal dysfunction in contrast media-induced nephropathy in Wistar rats

Contrast-induced nephropathy (CIN) is an iatrogenic medical event in stable cardiology patients that may lead to acute renal failure. There is no current successful therapy to manage CIN. Increasing evidence in experimental models and humans has suggested that this disease is associated with renal tubular and vascular injury triggered by oxidative stress. Considering the importance of reactive oxygen species (ROS) generation in the pathogenesis of CIN, the goal of the present study was to evaluate the effects of sildenafil on CIN development. Male Wistar rats were divided into control, CIN, and CIN pretreated with sildenafil (50 mg/kg/day). CIN was induced by water deprivation, NG-nitro-L-arginine methyl ester + indomethacin injections (10 mg/kg, intraperitoneally) and intravenous iohexol administration (3 g/kg). Renal function was evaluated through glomerular filtration rate (GFR), renal blood flow (RBF), plasma creatinine, uremia, and proteinuria. Oxidative stress was assessed by flow cytometry for intracellular ROS. Treatment with sildenafil attenuated the marked reduction of GFR and RBF in the CIN group. Moreover, sildenafil treatment in CIN rats reduced plasma creatinine, uremia, and proteinuria. Flow cytometry demonstrated that sildenafil attenuated the ROS production in the CIN group. These data suggest that sildenafil may be a new therapeutic agent to prevent CIN through its ability to preserve renal function and attenuate oxidative stress.

Gender-dependent effects of aging on the kidney

It is well known that the kidney plays an important role in the development of cardiovascular diseases such as hypertension. The normal aging process leads to changes in kidney morphology, hemodynamics and function, which increase the incidence of cardiovascular events in the elderly population. These disturbances are influenced by several factors, including gender. In general, females are protected by the effects of estrogens on the cardiorenal system. Several studies have demonstrated the beneficial effects of estrogens on renal function in the elderly; however, the relationships between androgens and kidney health during one's lifetime are not well understood. Sex steroids have many complex actions, and the decline in their levels during aging clearly influences kidney function, decreases the renal reserve and facilitates the development of cardiovascular disorders. Therefore, in this review, we discuss the cellular, biochemical, and molecular mechanisms by which sex hormones may influence renal function during the aging process.