NGAL: a new missing link between inflammation and uremic anemia?

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Renal Concerns in the Treatment of Chronic Hepatitis B with Tenofovir

Tenofovir, a third generation oral nucleos(t)ide analogue, currently represents one of the first-line drugs recommended for treating chronic hepatitis B virus (HBV) infection. After oral administration, tenofovir is mostly excreted in the urine by glomerular filtration and proximal tubular secretion. Hence, an impaired kidney function may lead to an increased renal exposure to the drug in patients with coexistent renal damage. This could further worsen kidney disease through different mechanisms of nephrotoxicity such as mitochondrial DNA depletion and tubular cytotoxicity. Despite several studies performed so far to assess tenofovir-related renal toxicity, data in HBV patients are not yet conclusive. Screening of risk factors for kidney disease before starting therapy and a careful monitoring of serum creatinine, glomerular filtration rate, serum phosphate and urine analysis during treatment are advocated to adjust the dose or stop treatment if needed. New biomarkers of tubular injury, such as neutrophil gelatinase associated lipocalin, could become helpful in the future for the timely identification and risk stratification of renal damage induced by tenofovir

Obestatin: a new element for mineral metabolism and inflammation in patients on hemodialysis.

Background: Obestatin plays a key role in the process of energy balance maintenance with an anorectic effect. The main aim of the study was to evaluate obestatin in uremic patients to determine whether it is correlated with nutritional and inflammatory status. Methods: We studied plasma obestatin in uremic patients (n = 50) undergoing hemodialysis therapy and in healthy subjects. Plasma obestatin was measured using an ELISA kit. Results: Obestatin levels in uremic patients were lower than in healthy subjects (p 23 had lower obestatin levels than those with a BMI Conclusions: Based on the present observational data, obestatin might be implicated in the inflammatory state and the disturbances of calcium/phosphate metabolism of hemodialysis patients. However, further studies are warranted to determine whether this hormone plays a key role in contributing to malnutrition and to the chronic inflammatory process

Short-term vascular hemodynamic responses to isometric exercise in young adults and in the elderly

Background: Vascular aging is known to induce progressive stiffening of the large elastic arteries, altering vascular hemodynamics under both rest and stress conditions. In this study, we aimed to investigate changes in vascular hemodynamics in response to isometric handgrip exercise across ages. Participants and methods: We included 62 participants, who were divided into three age categories: 20-40 (n=22), 41-60 (n=20), and 61-80 (n=20) years. Vascular hemodynamics were measured using the Mobil-o-Graph® based on the pulsatile pressure changes in the brachial artery. One-way ANOVA test was performed to analyze the changes induced by isometric handgrip exercise. Results: After isometric handgrip exercise, aortic pulse wave velocity (PWV) increased by 0.10 m/s in the youngest, 0.06 m/s in the middle-age, and 0.02 m/s in the oldest age category. Changes in PWV strongly correlated with those in central systolic blood pressure (cSBP) (r=0.878, P<0.01). After isometric exercise, the mean change of systolic blood pressure (SBP) was −1.9% in the youngest, 0.6% in the middle-aged, and 8.2% in the oldest subjects. Increasing handgrip strength was associated with an increase in SBP and cSBP (1.08 and 1.37 mmHg per 1 kg increase in handgrip strength, res

Arrhythmias and hemodialysis: role of potassium and new diagnostic tools.

Cardiovascular diseases represent the main causes of death in patients affected by renal failure, and arrhythmias are frequently observed in patients undergoing hemodialysis. Dialytic treatment per se can be considered as an arrhythmogenic stimulus; moreover, uraemic patients are characterized by a "pro-arrhythmic substrate" because of the high prevalence of ischaemic heart disease, left ventricular hypertrophy and autonomic neuropathy. One of the most important pathogenetic element involved in the onset of intra-dialytic arrhythmias is the alteration in electrolytes concentration, particularly calcium and potassium. It may be very useful to monitor the patient's cardiac activity during the whole hemodilaytic session. Nevertheless, the application of an extended intradialytic electrocardiographic monitoring is not simple because of several technical and structural impairments. We tried to overcome these difficulties using Whealthy, a wearable system consisting in a t-shirt composed of conductors and piezoresistive materials, integrated to form fibers and threads connected to tissutal sensors, electrodes, and connectors. ECG and pneumographic impedance signals are acquired by the electrodes in the tissue, and the data are registered by a small computer and transmitted via GPRS or Bluetooth

Modifications in relaxin’s serum levels during acetatefree biofiltration (AFB): only a new biomarker?

Aims.We evaluated relaxin’s behaviour during a haemodialytic session and the effects of its intradialytic variability on blood pressure. Methods. We enrolled 25 patients and evaluated relaxin’s levels during a haemodialytic session. We also dosed interdialytic relaxin and enrolled 10 healthy subjects and 16 patients with III stage chronic renal failure as controls. Results. Haemodialyzed patients have relaxin’s baseline concentrations higher than healthy controls, but lower than chronic patients. During the treatment, relaxin is removed; it increases again throughout the interdialytic phase. Furthermore, relaxin’s pre- haemodialytic concentration positively and significantly correlates with systolic, diastolic, and mean BP; such correlations disappear at the end of the treatment. Conclusion. Relaxin’s removal during the treatment may intervene in the pathogenesis of intradialytic hypertension. Hence, relaxin could be not only a new biomarker but also an active player in the intradialytic variations of blood pressure

Aquaporin-2 (AQP2) Urinary Excretion and Assumption of Water with Different Mineral Content in Healthy Subjects

The aquaporin-2 (AQP2) plays a key role in AVP-induced absorption of water, and its urinary excretion is related to its function. We aimed to test if the assumption of water with different mineral content can modify the expression of AQP2, leading to a change in AQP2 urinary concentration, in 20 healthy young subjects. Each subject received an oral water load (LM or HM) of 250 mL/hour for four hours, and several variables were measured. Plasmatic osmolality after water assumption was significantly reduced with no differences after the low (LM) or the high mineral (HM) water load. Urinary osmolality and plasmatic vasopressin concentration were significantly reduced after an assumption of both kinds of water. However, serum vasopressin was lower after HM water assumption than after LM. AQP2 urinary excretion was significantly reduced after water assumption with respect to the basal level and it was lower after LM than after HM water assumption. The different mineral content of water was investigated as a factor contributing to the development of hypertension. Considering that AQP2 can play a role in pathogenesis of hypertension, our demonstration that AVP-mediated AQP2 urinary excretion is strictly influenced by the consumption of water with different mineral content suggests a new, interesting field of investigation related to the link between blood pressure alterations and nutritional habits

Pulmonary Hypertension and Erythropoietin

Numerous uremic patients on hemodialysis have pulmonary hypertension attributable to the presence of arteriovenous fistulas, vascular calcification, and endothelial dysfunction due to alterations in the balance between vasoconstrictive and vasodilatory substances. For these reasons, the effects of recombinant human erythropoietin, a drug widely used in patients on dialysis, on the pulmonary circulation were studied. Some authors maintain that recombinant human erythropoietin has an antihypertensive effect, while others have observed that this hormone induces a reduction in pulmonary arterial pressure due to its vasoactive and stimulatory effects on endothelial and smooth muscle cell precursors