1.
Novel ideas about salt, blood pressure, and pregnancy.
Rakova, N, Muller, DN, Staff, AC, Luft, FC, Dechend, R
Journal of reproductive immunology. 2014;:135-139
Abstract
The molecular mechanisms leading to preeclampsia are poorly understood. It has been related to certain immune mechanisms, as well as the pathological regulation of the renin-angiotensin system together with perturbed salt and plasma volume regulation. Finally, a non-specific, vascular, inflammatory response is generated, which leads to the clinical syndrome. Here, we present novel findings in salt (NaCl) metabolism implying that salt is not only important in blood pressure control and volume homeostasis, but also in immune regulation. Sodium and chloride can be stored without accumulation of water in the interstitium at hypertonic concentrations through interactions with proteoglycans. Macrophages in the interstitium act as osmosensors for salt, producing increased amounts of vascular endothelial factor C, which increases the density of the lymph-capillary network and the production of nitric oxide in vessels. An increased interstitial salt concentration activates the innate immune system, especially Th17 cells, and may be an important trigger for autoimmune diseases. The novel findings with the idea of sodium storage and local mechanisms of volume and immune regulation are appealing for preeclampsia and may unify the "immune" and "vascular" hypotheses of preeclampsia.
2.
Austrian Moderate Altitude Study (AMAS 2000) - fluid shifts, erythropoiesis, and angiogenesis in patients with metabolic syndrome at moderate altitude (congruent with 1700 m).
Gunga, HC, Fries, D, Humpeler, E, Kirsch, K, Boldt, LE, Koralewski, E, Johannes, B, Klingler, A, Mittermayr, M, Röcker, L, et al
European journal of applied physiology. 2003;(6):497-505
Abstract
It was hypothesized that subjects with metabolic syndrome (hypertension, obesity, hyperlipidemia, diabetes mellitus): (1) develop measurable peripheral edema at moderate altitude and (2) might show differences on erythropoiesis, iron status and vascular endothelial growth factor (VEGF) in comparison to healthy subjects during and after a long-term stay (3-week exposure) at moderate altitude (congruent with 1700 m). Twenty-two male subjects with metabolic syndrome were selected. Baseline investigations (t1) were performed in Innsbruck (500 m). All participants were transferred by bus to 1700 m (Alps) and remained there for 3 weeks with examinations on day 1 (after the first night at altitude, t2), day 4 (t3), day 9 (t4) and day 19 (t5). After returning to Innsbruck, post-altitude examinations were conducted after 7-10 days (t6) and 6-7 weeks (t7), respectively. Body mass was decreased from t1 to t7 (P<0.01). Total body water was decreased at t2 (P<0.01), returned to control level (t3, t4), and was found elevated at t7 (P<0.01). Lean body mass did not change, but body fat decreased during the study (P<0.01). Tissue thickness at the forehead decreased during and after altitude exposure (P<0.01), whereas tissue thickness at the tibia did not alter. Erythropoietin (EPO) was elevated as early as t2 and remained increased until t5. Reticulocyte count was increased at t3 and remained above pre-altitude values. VEGF levels were unchanged. After a 3-week exposure to moderate altitude, patients with metabolic syndrome had reduced their body mass, mainly because of a reduction in body fat. The moderate altitude was found to stimulate erythropoiesis in these patients but this was not sufficient to increase serum VEGF concentration.