This review focuses on the effects of thyroid hormones in vascular and renal systems. Special emphasis is given to the mechanisms by which thyroid hormones affect the regulation of body fluids, vascular resistance and, ultimately, blood pressure. Vascular function is markedly affected by thyroid hormones that produce changes in vascular reactivity and endothelial function in hyper-and hypothyroidism. The hypothyroid state is accompanied by a marked decrease in sensitivity to vasoconstrictors, especially to sympathetic agonists, alteration that may play a role in the reduced blood pressure of hypothyroid rats, as well as in the preventive effects of hypothyroidism on experimental hypertension. Moreover, in hypothyroid rats, the endothelium-dependent and nitric oxide donors vasodilation is reduced. Conversely, the vessels from hyperthyroid rats showed an increased endothelium-dependent responsiveness that may be secondary to the shear-stress induced by the hyperdynamic circulation, and that may contribute to the reduced vascular resistance characteristic of this disease. Thyroid hormones also have important effects in the kidney, affecting renal growth, renal haemodynamics, and salt and water metabolism. In hyperthyroidism, there is a resetting of the pressure-natriuresis relationship related to hyperactivity of the renin-angiotensin system, which contributes to the arterial hypertension associated with this endocrine disease. Moreover, thyroid hormones affect the development and/or maintenance of various forms of arterial hypertension. This review also describes recent advances in our understanding of thyroid hormone action on nitric oxide and oxidative stress in the regulation of cardiovascular and renal function and in the long-term control of blood pressure.

The blood pressure lowering effect of a fruit and vegetable-rich diet is a necessary dietary lifestyle measure now included the guidelines for the management of arterial hypertension. Furthermore, flavonoids represent a major class of plant polyphenolics. The present review addresses the antihypertensive effect of quercetin, one of the most abundant flavonoids present in fruits and vegetables, and probably the best studied flavonoid because of its high biological activity. Quercetin has been shown to induce a progressive, dose-dependent and sustained reduction in blood pressure when given chronically in several rat models of hypertension, including spontaneously hypertensive rats, L-NAME-treated rats, DOCA-salt hypertensive rats, two-kidney one-clip Goldblatt rats, rats with aortic constriction and Dahl salt-sensitive hypertensive rats. Quercetin was also effective in reducing blood pressure in rat models of metabolic syndrome, including the obese Zucker rats as well as rats treated with a high-sucrose, high-fat diet. Quercetin also prevented morphological and functional changes in the heart, vessels and kidney, while increasing production of reactive oxygen species associated with hypertension. A high dose of quercetin also reduced blood pressure in stage 1 hypertensive patients in a randomized, double-blind, placebo-controlled, crossover study. Since raised blood pressure is the major cause of stroke as well as an important risk factor for ischemic heart disease, we propose that the blood pressure-lowering effect of quercetin could be an important mechanism contributing to the reduced risk of myocardial infarction and stroke observed with fruit and vegetables-rich diets, and possibly with flavonoid-rich diets.

Parasitic diseases affect billions of people and are considered a major public health issue. Close to 400 species are estimated to parasitize humans, of which around 90 are responsible for great clinical burden and mortality rates. Unfortunately, they are largely neglected as they are mainly endemic to poor regions. Of relevance to this review, there is accumulating evidence of the release of extracellular vesicles (EVs) in parasitic diseases, acting both in parasite–parasite inter-communication as well as in parasite–host interactions. EVs participate in the dissemination of the pathogen and play a role in the regulation of the host immune systems. Production of EVs from parasites or parasitized cells has been described for a number of parasitic infections. In this review, we provide the most relevant findings of the involvement of EVs in intercellular communication, modulation of immune responses, involvement in pathology, and their potential as new diagnostic tools and therapeutic agents in some of the major human parasitic pathogens.

The clinical and microbiologic characteristics of 31 patients with mucosal leishmaniasis due to Leishmania (Leishmania) infantum are described. Twenty-eight (90%) patients were male. Mean age at presentation was 48 +/- 14 years. Thirteen (42%) patients had no underlying disease, while 18 (58%) patients had several other medical conditions. Fifteen (48%) patients were immunocompromised, 7 patients were infected with human immunodeficiency virus (HIV), and 3 were graft recipients. The primary location of lesions was the larynx in 11 (35%) patients, oral mucosa in 10 (32%) patients, and the nose in 5 (16%) patients. Mucosal lesions were painless in all patients but 2 and consisted of whitish, red, or violaceous nodular swelling or tumorlike masses. Ulceration was reported in 6 patients. Pathologically, the lesions showed a chronic inflammatory infiltrate. Granuloma may be seen. The localization of the lesions determined the symptomatology of the disease. Symptoms included hoarseness, difficulty swallowing, and nasal obstruction. The disease presentation was usually protracted, with a mean time from the onset of symptoms to diagnosis of 13 months (range, 3 wk-4.5 yr), and the clinical diagnosis was usually mistaken for neoplasia of the upper aerodigestive tract. No laboratory abnormalities were found in these patients due to the localized disease, apart from those attributed to underlying diseases. Parasites were easily identified in smears or sections by Giemsa stain or hematoxylin-eosin stain. Leishmania was grown in culture in 12 (60%) patients; culture was negative in 8 (40%) patients. Leishmania (Leishmania) infantum was identified in only 9 instances. The following zymodemes were reported: MON-1 (2 patients), MON-24 (2 patients), MON-27 (1 patient), and MON-34 (1 patient). Serologic test results were known in 25 patients. Serology was usually positive at low titer; 6 (24%) patients had negative serologic test results. Twenty patients were treated with antimonial compounds for between 3 and 36 days. Three patients were given drugs other than antimonial drugs. Five patients were treated only locally, by surgery (3 patients) or topical medical therapy. One patient received no therapy, and treatment was not reported in 2 cases. Patients were cured in 25 (89%) cases, and sequelae were uncommon (14%). Relapse was detected in 2 individuals and 1 patient developed visceral leishmaniasis after treatment. Two HIV-coinfected patients died of causes unrelated to leishmaniasis. The results of the present report stress the clinical importance of searching for the presence of Leishmania in patients with suspected neoplasia of the upper respiratory tract if they have visited or resided in zones endemic for Leishmania (Leishmania) infantum. The treatment of choice for these patients is not established yet, but most patients respond to antimonial compounds given for 28 days or less.