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Along with epidemiologic transitions of the global population, the burden of aortic stenosis (AS) is rapidly increasing and transcatheter aortic valve replacement (TAVR) has quickly spread; indeed, it is nowadays also employed in treating patients with AS at intermediate operative risk. Nonetheless, the less invasive interventional strategy still carries relevant issues concerning post-procedural optimal antithrombotic strategy, given the current indications provided by guidelines are not completely supported by evidence-based data. Geriatric patients suffer from high bleeding and thromboembolic risks, whose balance is particularly subtle due to the presence of concomitant conditions, such as atrial fibrillation and chronic kidney disease, that make the post-TAVR antithrombotic management particularly insidious. This scenario is further complicated by the lack of specific evidence regarding the ‘real-life’ complex conditions typical of the geriatric syndromes, thus, the management of such a heterogeneous population, ranging from healthy ageing to frailty, is far from being defined. The aim of the present review is to summarize the critical points and the most updated evidence regarding the post-TAVR antithrombotic approach in the geriatric population, with a specific focus on the most frequent clinical settings.

Introduction Heart failure (HF) is frequently associated with comorbidities. 123I-metaiodobenzylguanidine (123I-mIBG) imaging constitutes an effective tool to measure cardiac adrenergic innervation and to improve prognostic stratification in HF patients, including the risk of major arrhythmic events. Although comorbidities have been individually associated with reduced cardiac adrenergic innervation, thus suggesting increased arrhythmic risk, very comorbid HF patients seem to be less likely to experience fatal arrhythmias. We evaluated the impact of the number of comorbidities on cardiac adrenergic innervation, assessed through 123I-mIBG imaging, in patients with systolic HF. Methods Patients with systolic HF underwent clinical examination, transthoracic echocardiography and cardiac 123I-mIBG scintigraphy. The presence of 7 comorbidities/conditions (smoking, chronic obstructive pulmonary disease, diabetes mellitus, peripheral artery disease, atrial fibrillation, chronic ischemic heart disease and chronic kidney disease) was documented in the overall study population. Results The study population consisted of 269 HF patients with a mean age of 66±11 years, a left ventricular ejection fraction (LVEF) of 31±7%, and 153 (57%) patients presented ≥3 comorbidities. Highly comorbid patients presented a reduced late heart to mediastinum (H/M) ratio, while no significant differences emerged in terms of early H/M ratio and washout rate. Multiple regression analysis revealed that the number of comorbidities was not associated with mIBG parameters of cardiac denervation, which were correlated with age, body mass index and LVEF. Conclusion In systolic HF patients, the number of comorbidities is not associated with alterations in cardiac adrenergic innervation. These results are consistent with the observation that very comorbid HF patients suffer lower risk of sudden cardiac death.

Background: One of the most challenging aspects related to Covid-19 is to establish which are the characteristics that may explain clinical variability among patients. To achieve this objective, we compared serum metabolomic profiles of asymptomatic SARS-CoV-2 carriers to patients affected by mild and severe symptoms.Methods: All subjects underwent quantitative assays for anti-SARS-CoV-2 antibody detection. Serum samples for metabolomic analysis were obtained from 109 healthy controls; 15 seroconverted, asymptomatic subjects (AS); 16 Covid-19 patients with mild symptomatology (MI) and 12 patients with severe symptomatology (SE). Metabolites were identified using Mass Spectrometry coupled to Gas Chromatography. Uni- and multivariate approaches were used to select the most relevant metabolites. Results: Anti SARS-CoV-2 IgG showed an increasing trend from controls to asymptomatic and mild severity patients. Tyrosine, phenylalanine, acetoacetate and fumarate showed a decreased concentration in MI compared to both CTRL and AS subjects; on the contrary, mandelic acid showed an increased concertation. The shortest route among these metabolites resulted the Tyrosine metabolism. Aspartic acid, alanine, isoleucine, valine and proline were decreased in MI patients, while methionine and oxo-leucine resulted increased. An increased concertation of fatty acids lauric and myristic acid, phospholipids (phosphatidyl myo-inositol and lyso-phosphatidyl inositol) and histamine were recorded in MI and SE. Conclusion: The reported metabolite levels could be explained by an increase production of L-DOPA, resulting in a following increased production of noradrenaline and adrenaline that could, at least partially, explain the different clinical presentation of the infection.

Food plays a central role in health, especially through consumption of plant-derived foods. Functional foods, supplements, and nutraceuticals are increasingly entering the market to respond to consumer demand for healthy products. They are foods, supplements, and ingredients which offer health benefits beyond the standard nutritional value. Some benefits are associated with phenolic compounds and phytochemicals with antioxidant properties. An olive p&acirc, t&eacute, (OP) was added with antioxidants derived from olive mill wastewater (OMWW) to obtain a functional product rich in phenolic compounds. The olive p&acirc, is produced from the ground olive pericarp, which shows an excellent natural antioxidant content. The OMWW is a waste product from oil processing, which is also rich in phenolic compounds. The result was a product rich in trans-resveratrol, OH tyrosol, and tyrosol in concentrations such as satisfying the European community&rsquo, s claims regarding the possible antioxidant action on plasma lipids with excellent shelf-life stability. The total phenolic content was assayed by a colorimetric method, the antioxidant activity by the ABTS [(2,2&prime, azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)] test, the phenolic profile by Q Exactive Orbitrap LC-MS/MS. The shelf-life stability was confirmed by yeast, molds, and total microbial count, pH, and water activity determinations, and the best pasteurization parameters were determined. The palatability was judged as excellent.

Background and objectives: Olive p&acirc, t&eacute, (OP) is an olive-derived product with potentially beneficial effects on human health due to the presence of natural antioxidants. The present dietary supplementation study aimed to evaluate the effects on blood antioxidant levels of an olive p&acirc, reinforced with natural antioxidants (ROP) recovered from olive mill waste. Materials and methods: Ninety-eight healthy volunteers (M = 54, 55%, age 18&ndash, 25) were divided into two groups: A (n = 49), practicing three or more days of physical activity a week, and B (n = 49), practicing less than two. Each group was split into two subgroups, receiving dietary supplementation with OP or ROP. The status of smoker was also recorded, and a biological antioxidant potential (BAP) test was performed on each subject. Results: The BAP values increased with both OP (n = 30) and ROP (n = 68) but ROP supplementation showed higher increments (736.9 &mu, mol/L) than OP (339.6). The increment was significantly higher for smokers (n = 15), 1122.9 vs. non-smokers (n = 53), 635.7, with values in percent of baseline, respectively, 34.6% and 16.2% (P &lt, 0.01). Conclusions: The ROP nutritional supplementation appears useful to increase antioxidant activity, with better effect in smokers, further studies should confirm the finding and investigate its biological bases.

Background Benign Pancreatic Hyperenzymemia (BPH) is characterized by a long-term increase of serum pancreatic enzymes (PE) in otherwise healthy subjects. The study investigates the prevalence and correlates of the condition using data from Electronic Health Records (EHR) in a large sample of general population, to identify subjects potentially affected by BPH. Methods Cross-sectional retrospective observational study integrated by a follow-up visit. Results The database of a reference laboratory identified, out of 577.251 admittances from 2011 to 2015, 4964 patients tested at least for one PE assay and 1688 subjects who had at least 3 PE tests (normal or increased) over two years. Forty-two individuals showed an increase of PE at least three times throughout 2 years without any evidence of pancreatic disease, even after matching with the ICD 9-CM code in the GPs database. Data retrieved at follow-up visit showed that for 34 the diagnosis of BPH could be made. Conclusions Our data indicate that BPH prevalence among subjects underwent blood testing for multiple PE testing is 2%. This condition, even if not a disease, is perceived by nearly all the BPH patients as a serious threat to their life. Further studies are needed to manage its heavy psychological impact.

Plants emit volatile organic compounds (VOCs) that induce metabolomic, transcriptomic, and behavioral reactions in receiver organisms, including insect pollinators and herbivores. VOCs’ composition and concentration may influence plant-insect or plant-plant interactions and affect soil microbes that may interfere in plant-plant communication. Many Trichoderma fungi act as biocontrol agents of phytopathogens and plant growth promoters. Moreover, they can stimulate plant defense mechanisms against insect pests. This study evaluated VOCs’ emission by olive trees (Olea europaea L.) when selected Trichoderma fungi or metabolites were used as soil treatments. Trichoderma harzianum strains M10, T22, and TH1, T. asperellum strain KV906, T. virens strain GV41, and their secondary metabolites harzianic acid (HA), and 6-pentyl-α-pyrone (6PP) were applied to olive trees. Charcoal cartridges were employed to adsorb olive VOCs, and gas chromatography mass spectrometry (GC-MS) analysis allowed their identification and quantification. A total of 45 volatile compounds were detected, and among these, twenty-five represented environmental pollutants and nineteen compounds were related to olive plant emission. Trichoderma strains and metabolites differentially enhanced VOCs production, affecting three biosynthetic pathways: methylerythritol 1-phosphate (MEP), lipid-signaling, and shikimate pathways. Multivariate analysis models showed a characteristic fingerprint of each plant-fungus/metabolite relationship, reflecting a different emission of VOCs by the treated plants. Specifically, strain M10 and the metabolites 6PP and HA enhanced the monoterpene syntheses by controlling the MEP pathway. Strains GV41, KV906, and the metabolite HA stimulated the hydrocarbon aldehyde formation (nonanal) by regulating the lipid-signaling pathway. Finally, Trichoderma strains GV41, M10, T22, TH1, and the metabolites HA and 6PP improve aromatic syntheses at different steps of the shikimate pathway.

Heart failure (HF) represents the end-stage condition of several structural and functional cardiovascular diseases, characterized by reduced myocardial pump function and increased pressure load. The dysregulation of neurohormonal systems, especially the hyperactivity of the cardiac adrenergic nervous system (ANS), constitutes a hallmark of HF and exerts a pivotal role in its progression. Indeed, it negatively affects patients’ prognosis, being associated with high morbidity and mortality rates, with a tremendous burden on global healthcare systems. To date, all the techniques proposed to assess the cardiac sympathetic nervous system are burdened by intrinsic limits that hinder their implementation in clinical practice. Several biomarkers related to ANS activity, which may potentially support the clinical management of such a complex syndrome, are slow to be implemented in the routine practice for several limitations due to their assessment and clinical impact. Lymphocyte G-protein-coupled Receptor Kinase 2 (GRK2) levels reflect myocardial β-adrenergic receptor function in HF and have been shown to add independent prognostic information related to ANS overdrive. In the present manuscript, we provide an overview of the techniques currently available to evaluate cardiac ANS in HF and future perspectives in this field of relevant scientific and clinical interest.

Background. Folate therapy reduces, but does not normalize homocysteine (Hcy) levels, frequently elevated in chronic kidney disease (CKD). The mechanisms of this folate resistance are unknown. Cellular acquisition of folate is mediated by folate receptors (FRs), whose expression is also modulated by folate status, through an Hcy-dependent regulation mechanism involving heterogeneous nuclear ribonucleoprotein-E1 (hnRNP-E1). Our objective was to evaluate whether an alteration of the FR2 (the form present in nucleated blood cells) expression is present in CKD patients on hemodialysis (HD), and its susceptibility to folate treatment. Methods. A population of chronic uremic patients on HD was enrolled, along with a control group, and studies on FR2 receptor expression and related items were performed in plasma and mononuclear cells from peripheral blood. A subgroup of patients was treated with ev methyltetrahydrofolate for one month. Results. In HD, there was a significant reduction in FR2 protein expression compared to controls, not correlated with Hcy concentrations, while its mRNA levels were significantly increased. After folate treatment, there was a significant mRNA decrease, in the absence of significant changes in receptor protein expression. hnRNP-E1 gene and protein expression levels increased pre-treatment, while decreased post-treatment. Conclusions. In HD, FR2 expression is altered in peripheral mononuclear cells, since its levels are decreased and are not responsive to variations in Hcy concentration, while the intracellular machinery (receptor mRNA and hnRNP-E1), possibly triggering its regulation, is conserved. These findings provide insight into the mechanisms of folate resistance in uremia. Background Folate therapy reduces, but does not normalize homocysteine (Hcy) levels, frequently elevated in chronic kidney disease (CKD). The mechanisms of this folate resistance are unknown. Cellular acquisition of folate is mediated by folate receptors (FRs), whose expression is also modulated by folate status, through an Hcy-dependent regulation mechanism involving heterogeneous nuclear ribonucleoprotein-E1 (hnRNP-E1). Our objective was to evaluate whether an alteration of the FR2 (the form present in nucleated blood cells) expression is present in CKD patients on haemodialysis (HD), and its susceptibility to folate treatment. Methods A population of chronic uraemic patients on HD was enrolled, along with a control group, and studies on FR2 receptor expression and related items were performed in plasma and mononuclear cells from peripheral blood. A subgroup of patients was treated with methyltetrahydrofolate for 1 month.ResultsIn HD, there was a significant reduction in FR2 protein expression compared with controls, not correlated with Hcy concentrations, while its mRNA levels were significantly increased. After folate treatment, there was a significant mRNA decrease, in the absence of significant changes in receptor protein expression. hnRNP-E1 gene and protein expression levels increased pre-treatment, while decreased post-treatment. Conclusions In HD, FR2 expression is altered in peripheral mononuclear cells, since its levels are decreased and are not responsive to variations in Hcy concentration, while the intracellular machinery (receptor mRNA and hnRNP-E1), possibly triggering its regulation, is conserved. These findings provide insight into the mechanisms of folate resistance in uraemia. © 2013 © The Author 2013. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Hydrogen sulfide (H(2)S) is a poisonous gas which can be lethal. However, it is also produced endogenously, thus belonging to the family of gasotransmitters along with nitric oxide and carbon monoxide. H(2)S is in fact involved in mediating several signaling and cytoprotective functions, for example in the nervous, cardiovascular, and gastrointestinal systems, such as neuronal transmission, blood pressure regulation and insulin release, among others. When increased, it can mediate inflammation and apoptosis, with a role in shock. When decreased, it can be involved in atherosclerosis, hypertension, myocardial infarction, diabetes, sexual dysfunction, and gastric ulcer; it notably interacts with the other gaseous mediators. Cystathionine γ-lyase, cystathionine β-synthase, and 3-mercaptopyruvate sulfurtransferase are the principal enzymes involved in H(2)S production. We have recently studied H(2)S metabolism in the plasma of chronic hemodialysis patients and reported that its levels are significantly decreased. The plausible mechanism lies in the transcription inhibition of the cystathionine γ-lyase gene. The finding could be of importance considering that hypertension and high cardiovascular mortality are characteristic in these patients. Hydrogen sulfide (H2S) is a poisonous gas which can be lethal. However, it is also produced endogenously, thus belonging to the family of gasotransmitters along with nitric oxide and carbon monoxide. H2S is in fact involved in mediating several signaling and cytoprotective functions, for example in the nervous, cardiovascular, and gastrointestinal systems, such as neuronal transmission, blood pressure regulation and insulin release, among others. When increased, it can mediate inflammation and apoptosis, with a role in shock. When decreased, it can be involved in atherosclerosis, hypertension, myocardial infarction, diabetes, sexual dysfunction, and gastric ulcer; it notably interacts with the other gaseous mediators. Cystathionine γ-lyase, cystathionine β-synthase, and 3-mercaptopyruvate sulfurtransferase are the principal enzymes involved in H2S production. We have recently studied H2S metabolism in the plasma of chronic hemodialysis patients and reported that its levels are significantly decreased. The plausible mechanism lies in the transcription inhibition of the cystathionine γ-lyase gene. The finding could be of importance considering that hypertension and high cardiovascular mortality are characteristic in these patients. Copyright © 2011 S. Karger AG, Basel.

Hydrogen sulfide, H2S, is the third endogenous gas with cardiovascular properties, after nitric oxide and carbon monoxide. H2S is a potent vasorelaxant, and its deficiency is implicated in the pathogenesis of hypertension and atherosclerosis. Cystathionine beta-synthase, cystathionine gamma- lyase, and 3-mercaptopyruvate sulfurtransferase catalyze H2S formation. Chronic kidney disease is characterized by high prevalence of hyperhomocysteinemia, hypertension, and high cardiovascular mortality, especially in hemodialysis patients. H2S levels are decreased in hemodialysis patients through transcriptional deregulation of genes encoding for the H2S-producing enzymes. Potential implications relate to the pathogenesis of the manifestations of the uremic syndrome, such as hypertension and atherosclerosis. (C) 2010 by the National Kidney Foundation, Inc. All rights reserved.

Hyperhomocysteinemia is an independent cardiovascular risk factor, according to most observational studies and to studies using the Mendelian randomization approach, utilizing the common polymorphism C677T of methylene tetrahydrofolate reductase. In contrast, the most recent secondary preventive intervention studies, in the general population and in chronic kidney disease (CKD) and uremia, which are all negative (with the possible notable exception of stroke), point to other directions. However, all trials use folic acid in various dosages as a means to reduce homocysteine levels, with the addition of vitamins B6 and B12. It is possible that folic acid has negative effects, which offset the benefits; alternatively, homocysteine could be an innocent by-stander, or a surrogate of the real culprit. The latter possibility leads us to the search for potential candidates. First, the accumulation of homocysteine in blood leads to an intracellular increase of S-adenosylhomocysteine (AdoHcy), a powerful competitive methyltransferase inhibitor, which by itself is considered a predictor of cardiovascular events. DNA methyltransferases are among the principal targets of hyperhomocysteinemia, as studies in several cell culture and animal models, as well as in humans, show. In CKD and in uremia, hyperhomocysteinemia and high intracellular AdoHcy are present and are associated with abnormal allelic expression of genes regulated through methylation, such as imprinted genes, and pseudoautosomal genes, thus pointing to epigenetic dysregulation. These alterations are susceptible to reversal upon homocysteine-lowering therapy obtained through folate administration. Second, it has to be kept in mind that homocysteine is mainly protein-bound, and its effects could be linked therefore to protein homocysteinylation. In this respect, increased protein homocysteinylation has been found in uremia, leading to alterations in protein function. © 2009 Wiley Periodicals, Inc.

H2S is the third endogenous gaseous mediator, after nitric oxide and carbon monoxide, possessing pleiotropic effects, including cytoprotection and anti-inflammatory action. We analyzed, in an in vitro model entailing monocyte adhesion to an endothelial monolayer, the changes induced by H 2S on various potential targets, including cytokines, chemokines, and proteases, playing a crucial role in inflammation and cell adhesion. Results show that H2S prevents the increase in monocyte adhesion induced by tumor necrosis factor-α (TNF-α). Under these conditions, downregulation of monocyte chemoattractant protein-1 (MCP-1), chemokine C-C motif receptor 2, and increase of cluster of differentiation 36 could be detected in monocytes. In endothelial cells, H2S treatment reduces the increase in MCP-1, inter-cellular adhesion molecule-1, vascular cell adhesion molecule-1, and of a disintegrin and metalloproteinase metallopeptidase domain 17 (ADAM17), both at the gene expression and protein levels. Cystathionine γ-lyase and 3-mercaptopyruvate sulfurtransferase, the major H2S forming enzymes, are downregulated in endothelial cells. In addition, H2S significantly reduces activation of ADAM17 by PMA in endothelial cells, with consequent reduction of both ADAM17-dependent TNF-α ectodomain shedding and MCP-1 release. In conclusion, H2S is able to prevent endothelial activation by hampering endothelial activation, triggered by TNF-α. The mechanism of this protective effect is mainly mediated by down-modulation of ADAM17-dependent TNF-converting enzyme (TACE) activity with consequent inhibition of soluble TNF-α shedding and its relevant MCP-1 release in the medium. These results are discussed in the light of the potential protective role of H2S in pro-inflammatory and pro-atherogenic processes, such as chronic renal failure. © 2013 Wiley Periodicals, Inc.

Objective: Uremia represents a state where hyperhomocysteinemia is resistant to folate therapy, thus undermining intervention trials' efficacy. N-acetylcysteine (NAC), an antioxidant, in addition to folates (5-methyltetrahydrofolate, MTHF), was tested in a population of hemodialysis patients. Design: The study is an open, parallel, intervention study. Setting: Ambulatory chronic hemodialysis patients. Subjects: Clinically stable chronic hemodialysis patients, on hemodialysis since more than 3 months, undergoing a folate washout. Control group on standard therapy (n = 50). Intervention: One group was treated with intravenous MTHF (MTHF group, n = 48). A second group was represented by patients treated with MTHF, and, during the course of 10 hemodialysis sessions, NAC was administered intravenous (MTHF + NAC group, n = 47). Main Outcome Measure: Plasma homocysteine measured before and after dialysis at the first and the last treatment. Results: At the end of the study, there was a significant decrease in predialysis plasma homocysteine levels in the MTHF group and MTHF + NAC group, compared with the control group, but no significant difference between the MTHF group and MTHF + NAC group. A significant decrease in postdialysis plasma homocysteine levels in MTHF + NAC group (10.27 ± 0.94 μmol/L, 95% confidence interval: 8.37-12.17) compared with the MTHF group (16.23 ± 0.83, 95% confidence interval: 14.55-17.90) was present. In the MTHF + NAC group, 64% of patients reached a postdialysis homocysteine level

Background. Hydrogen sulphide, H2S, is the third endogenous gas with putative cardiovascular properties, after nitric oxide and carbon monoxide. H2S is a vasorelaxant, while H2S deficiency is implicated in the pathogenesis of hypertension and atherosclerosis. Cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulphurtransferase (MPS) catalyze H2S formation, with different relative efficiencies. Chronic kidney disease (CKD) is characterized by elevation of both plasma homocysteine and cysteine, which are substrates of these enzymes, and by a high prevalence of hypertension and cardiovascular mortality, particularly in the haemodialysis stage. It is possible that the H2S-generating pathways are altered as well in this patient population. Methods. Plasma H2S levels were measured with a common spectrophotometric method. This method detects various forms of H2S, protein-bound and non-protein-bound. Blood sulphaemoglobin, a marker of chronic exposure to H2S, was also measured, as well as related sulphur amino acids, vitamins and transcriptional levels of relevant genes, in haemodialysis patients and compared to healthy controls. Results. Applying the above-mentioned methodology, H2S levels were found to be decreased in patients. Sulphaemoglobin levels were significantly lower as well. Plasma homocysteine and cysteine were significantly higher; vitamin B6, a cofactor in H2S biosynthesis, was not different. H2S correlated negatively with cysteine levels. CSE expression was significantly downregulated in haemodialysis patients. Conclusions. Transcriptional deregulation of genes encoding for H2S-producing enzymes is present in uraemia. Although the specificity of the method employed for H2S detection is low, the finding that H2S is decreased is complemented by the lower sulphhaemoglobin levels. Potential implications of this study relate to the pathogenesis of the uraemic syndromemanifestations, such as hypertension and atherosclerosis. Background. Hydrogen sulphide, H2S, is the third endogenous gas with putative cardiovascular properties, after nitric oxide and carbon monoxide. H2S is a vasorelaxant, while H2S deficiency is implicated in the pathogenesis of hypertension and atherosclerosis. Cystathionine beta-synthase (CBS), cystathionine gamma-lyase (CSE) and 3-mercaptopyruvate sulphurtransferase (MPS) catalyze H2S formation, with different relative efficiencies. Chronic kidney disease (CKD) is characterized by elevation of both plasma homocysteine and cysteine, which are substrates of these enzymes, and by a high prevalence of hypertension and cardiovascular mortality, particularly in the haemodialysis stage. It is possible that the H2S-generating pathways are altered as well in this patient population.Methods. Plasma H2S levels were measured with a common spectrophotometric method. This method detects various forms of H2S, protein-bound and non-protein-bound. Blood sulphaemoglobin, a marker of chronic exposure to H2S, was also measured, as well as related sulphur amino acids, vitamins and transcriptional levels of relevant genes, in haemodialysis patients and compared to healthy controls.Results. Applying the above-mentioned methodology, H2S levels were found to be decreased in patients. Sulphaemoglobin levels were significantly lower as well. Plasma homocysteine and cysteine were significantly higher; vitamin B-6, a cofactor in H2S biosynthesis, was not different. H2S correlated negatively with cysteine levels. CSE expression was significantly downregulated in haemodialysis patients.Conclusions. Transcriptional deregulation of genes encoding for H2S-producing enzymes is present in uraemia. Although the specificity of the method employed for H2S detection is low, the finding that H2S is decreased is complemented by the lower sulphhaemoglobin levels. Potential implications of this study relate to the pathogenesis of the uraemic syndrome manifestations, such as hypertension and atherosclerosis.

To the Editor: Hydrogen sulfide, H2S, the third endogenous gas with cardiovascular properties after nitric oxide and carbon monoxide, is a newly recognized vasorelaxant, and H2S deficiency is involved in the pathogenesis of hypertension and atherosclerosis.1 We demonstrated that in hemodialysis patients, H2S levels are decreased through transcriptional deregulation of genes encoding H2S-producing enzymes.2 In fact, gene expression of cystathionine γ-lyase (CSE), an enzyme implicated in H2S formation, is downregulated in these patients.2 We measured H2S levels before and after a single standard 4-h hemodialysis session in 131 patients, in two dialysis sessions separated by 1 month. Measurement was performed by a slight modification of our previously published method.2 Basically, a 20-min incubation period was added before deproteinization. Homocysteine is a main direct H2S precursor in vivo, which functions through the catalytic activity of either cystathionine β-synthase or CSE (see Perna et al.3 for a review). Plasma total homocysteine was also measured by using high-performance liquid chromatography separation and fluorescence detection.4