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Inada and Ido identified Leptospira sp. as the pathogen responsible for Weil's Disease in 1915. Later, it was confirmed that Leptospira causes leptospirosis. The host microorganism's interaction at the cellular level remained misunderstood for many years. Although different bacterial components have been isolated and purified, the complexity of the molecular interactions between these components and the host and the molecular mechanisms responsible for the systemic dysfunctions still needs to be fully unveiled. Leptospirosis affects virtually all animal species. Its cellular pathophysiology must involve a ubiquitous cellular mechanism in all eukaryotes. Na/K-ATPase is the molecular target of the leptospiral endotoxin (glycolipoprotein-GLP). Na/K-ATPase dysfunctions on different types of cells give rise to the organ disorders manifested in leptospirosis. Concomitantly, the development of a peculiar metabolic disorder characterized by dyslipidemia, with increased levels of circulating free fatty acids and an imbalance in the fatty acid/albumin molar ratio, triggers events of cellular lipotoxicity. Synergistically, multiple molecular stimuli are prompted during the infection, activating inflammasomes and Na/K-ATPase signalosome, leading to pro-inflammatory and metabolic alterations during leptospirosis. Leptospirosis involves diverse molecular mechanisms and alteration in patient inflammatory and metabolic status. Nonetheless, Na/K-ATPase is critical in the disease, and it is targeted by GLP, its components, and other molecules, such as fatty acids, that inhibit or trigger intracellular signaling through this enzyme. Herein, we overview the role of Na/K-ATPase during leptospirosis infection as a potential therapeutic target or an indicator of disease severity.

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INTRODUCTION: Patient who was undergoing hemodialysis (HD) thrice weekly usually gain 1 to 4 kg of weight in interdialytic period, mainly due to fluid accumulation by ingestion of water. Ultrafiltration (UF) during HD will be need to remove fluid excess to avoid severe medical complications secondary to fluid overload. However, in pregnant woman UF can increase the episodes of intradialytic hypotension which may lead to placental ischemic injury and predispose to fetal distress. There is little information about safe fluid amount withdrawn by UF during pregnancy. METHODS: We prospectively study by obstetric Doppler ultrasonography the fluxometric parameters: pulsatility index (PI) and resistance index (RI) of fetal middle cerebral, uterine, and umbilical artery obtained at the beginning and the end of HD session, the acute and chronic effect of UF on placenta and fetus blood flow, as well as the fetal outcome in 1 pregnant woman on chronic HD. FINDINGS: We did not observe any acute harmful effect on fetal middle cerebral, placental and umbilical artery blood flow when UF rate of 2.1 ± 0.04 L (6 < 8 mL/h/kg) during HD session, no significant statistical difference was observed when compared PI and RI before and after UF and also when we compared these data with reference value on normal pregnancy to the same gestational age. DISCUSSION: UF rate of 6 < 8 mL/h/kg during HD did not bring any acute harmful effect on fetal middle cerebral, placental, and umbilical blood flow and the UF rate of 1.4 6 0.4 L (< 6 mL/h/kg) / HD session that was done in all others HD during pregnancy was safe, without any chronic fetal deleterious effect. Obstetric Doppler ultrasonography is a simple and noninvasive method to fetal follow-up and can aid to determine safe UF rate in pregnant women during gestation.

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RESUMEN

A leptospirose humana é uma doença infecciosa aguda de amplo espectro clínico e que cursa com alterações metabólicas e dislipidêmicas envolvendo colesterol total e frações, triglicerídeos e ácidos graxos não esterificados (AGNEs). Dentre os mecanismos celulares envolvidos na sua fisiopatologia encontram-se a inibição da enzima Na, K ATPase pela endotoxina GLP e a lipotoxicidade, ambos agravados pela redução dos níveis circulantes da albumina, molécula que exerce um papel fundamental na adsorção de moléculas lipídicas. Neste estudo observacional, determinamos as concentrações séricas de bilirrubina, creatinina e albumina e, pela técnica de cromatografia líquida de alta performance, a concentração sérica dos AGNEs de cadeia longa (C16: C18) de 27 pacientes com síndrome de Weil durante o período de internação hospitalar, dos quais cinco vieram a falecer. Verificamos correlações significantes (p<0,05) ao longo da internação hospitalar, nas concentrações séricas de marcadores bioquímicos de gravidade da doença (bilirrubina, creatinina e albumina), AGNEs, ácido oléico e ácido linoléico, e relação molar ácido oléico/albumina, com r (Pearson) de -0,7981, -0,7699, 0,9014, -0,8795 -0,9816, -0,9694, -0,9821, respectivamente. A relação molar ácido oléico/albumina e ácido oléico+linoléico/albumina foi significantemente mais elevada nos pacientes que faleceram (p<0,001), retornando aos valores semelhantes aos do grupo controle nos pacientes que evoluíram para a cura. Na análise por Curva Roc, a relação molar ácido oléico/albumina se mostrou um bom teste preditivo, com valor de corte 0,705 associado com maior especificidade e sensibilidade prognóstica. Nossos resultados sugerem que a utilização parenteral da albumina humana em pacientes com leptospirose pode ser uma potente ferramenta terapêutica nos casos mais graves ao interferir positivamente no resgate do equilíbrio bioquímico das relações molares ácido oléico/algumina e ácido oléico+linoléico/algumina.

Human leptospirosis is an acute infectious disease with a broad clinical spectrum. It courses with metabolic and dyslipidemic alterations, involving total cholesterol and fractions, triglycerides and nonesterified fatty acids (NEFAs). The cellular mechanisms involved in its pathogenesis include the inhibition of the enzyme sodium-potassium adenosine triphosphatase and lipotoxicity. Both mechanisms are aggravated by the reduction of serum levels of albumin, a molecule that plays a fundamental role in the absorption of lipid molecules. In this observational study, we determined the serum concentrations of bilirubin, creatinine and albumin, and, by High Performance Liquid Chromatography, the serum concentrations of long chain NEFAs (C16: C18) during the period of hospitalization of 27 patients with Weil's syndrome, five of whom progressed to death. Significant correlations were found between the length of hospitalization and serum concentrations of biochemical markers of severity (bilirubin, creatinine, albumin), NEFAs, oleic acid and linoleic acid, and the oleic acid: albumin molar ratio, with r (Pearson) of de -0,7981, -0,7699, 0,09014, -0,8795 -0,9816, -0,9694, -09821 respectively. The oleic acid: albumin molar ratio and oleic-plus-linoleic acid: albumin molar ratio were significantly higher in the patients who progressed to death, whereas in the cured patients this ratio decreased to levels that were similar to those found in the control group. Roc Curve analysis for the acid oleic: albumin molar ratio proved a good predictive test, with value of cutting 0.705 associated with greater specificity and prognostic sensitivity. Our results suggest that parenteral administration of human albumine may interfere positively in the rescue of biochemical balance of oleic acid: albumin molar ratio and oleic-plus-linoleic acid: albumin molar ratio and be a therapeutic tool for severe cases of leptospirosis.

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