Gut microbiome in hemodialysis patients treated with calcium acetate or treated with sucroferric oxyhydroxide: a pilot study.

PURPOSE: It has been proved that the gut microbiome is altered in patients with chronic kidney disease. This contributes to chronic inflammation and increases cardiovascular risk and mortality, especially in those undergoing hemodialysis. Phosphate binders may potentially induce changes in their microbiome. This trial aimed to compare the changes in the gut microbiome of hemodialysis patients treated with calcium acetate to those treated with sucroferric oxyhydroxide. METHODS: Twelve hemodialysis patients were distributed to receive calcium acetate or sucroferric oxyhydroxide for 5 months. Blood samples (for biochemical analysis) and stool samples (for microbiome analysis) were collected at baseline, 4, 12, and 20 weeks after treatment initiation. Fecal DNA was extracted and a 16S rRNA sequencing library was constructed targeting the V3 and V4 hypervariable regions. RESULTS: Regarding clinical variables and laboratory parameters, no statistically significant differences were observed between calcium acetate or sucroferric oxyhydroxide groups. When analyzing stool samples, we found that all patients were different (p = 0.001) among themselves and these differences were kept along the 20 weeks of treatment. The clustering analysis in microbial profiles grouped the samples of the same patient independently of the treatment followed and the stage of the treatment. CONCLUSION: These results suggest that a 5-month treatment with either calcium acetate or sucroferric oxyhydroxide did not modify baseline diversity or baseline bacterial composition in hemodialysis patients, also about the high-variability profiles of the gut microbiome found among these patients.

Preload dependence of pulmonary haemodynamics and right ventricular performance.

AIMS: Systolic pulmonary artery pressure (SPAP) and right heart adaptation in relation to pre-existing preload are often disregarded. To determine volume-related changes in the pulmonary-right ventricle (RV) unit and the preload dependence of its components, we analysed pulmonary haemodynamics and right ventricular performance, taking advantage of the plasma volume removal associated to haemodialysis (HD). METHODS AND RESULTS: Fifty-three stable patients on chronic HD with LVEF > 50% and without heart failure were recruited (mean age 63.0 ± 12.4 years; 31.2% women; hypertension in 89% and diabetes in 53%) and evaluated just before and after HD (mean ultrafiltration volume 2.4 ± 0.7 l). SPAP from both times were available in 39 patients. After HD, SPAP decreased (42.2 ± 12.6 to 33.7 ± 11.6 mmHg, p < 0.001) without modification of non-invasive pulmonary vascular resistance (1.75 ± 0.44 to 1.75 ± 0.40 eWU, p = 0.94). Age and drop in the E/e' ratio were the variables associated with greater reduction in PASP (p = 0.022 and p = 0.049, respectively). A significant reduction of right chamber sizes was observed, along with a diminution in measures of RV contractility, excluding RV longitudinal strain. Functional tricuspid regurgitation (FTR) diminution was observed in 26% of patients, occurring in every case with more than mild FTR. On multivariate analyses, left atrial size was the only predictor of pulmonary hypertension (defined as SPAP > 40 mmHg) (OR 1.29 (1.07-1.56), p = 0.006). CONCLUSION: Rapid volemic changes may affect FTR grading, RV size and contractility, with RV longitudinal strain being less variable than conventional parameters. SPAP decreases after HD, and this reduction is related to age and greater diminution of the E/e' ratio.

Ambrisentan use in a HIV-1 infected patient with end-stage renal disease and pulmonary hypertension: minimal removal by hemodialysis - a case report.

BACKGROUND: Ambrisentan is a selective endothelin receptor antagonist used for the treatment of pulmonary arterial hypertension (PAH). Little is known about ambrisentan removal by hemodialysis in patients with end-stage renal disease (ESRD). CASE PRESENTATION: A 53-year-old woman with HIV/hepatitis C virus (HCV) co-infection, PAH and ESRD on regular hemodialyis was admitted in our hospital due to refractory heart failure while on treatment with bosentan (125 mg twice daily) and tadalafil (20 mg once daily) for PAH and antiretroviral treatment (cART) including darunavir/cobicistat (800/150 mg once daily). Excessive exposure to bosentan due to drug interactions between bosentan and darunavir/cobicistat was suspected. Bosentan was replaced by ambrisentan, with progressive improvement in her clinical condition. Pre- and postdialyzer cocentrations of ambrisentan in plasma were determined and hemodialysis extraction ratio for ambrisentan was 2%. CONCLUSIONS: Our results suggest that hemodialysis results in minimal ambrisentan removal, and therefore no specific ambrisentan dosage adjustment seems to be required in ESRD patients undergoing hemodialysis.

Molecular profile of urine extracellular vesicles from normo-functional kidneys reveal minimal differences between living and deceased donors.

BACKGROUND: Kidney transplantation (KTx) is the best therapeutic approach for chronic kidney diseases leading to irreversible kidney failure. Considering the origin of the graft, several studies have reported differences between living (LD) and deceased donors (DD) in graft and patient survival. These differences seem to be related to multiple factors including, donor age and time of cold ischemia among others. Many of transplanted organs come from old-aged DDs, in which pre-transplant biopsy is recommended. However, kidney biopsy has several limitations, and there is a need to develop alternatives to assess the status of a kidney before transplantation. As the analysis of urinary extracellular vesicles (uEVs) rendered promising results as non-invasive biomarkers of kidney-related pathologies, this pilot study aimed to investigate whether profiling uEVs of LDs and DDs may be of help to assess the quality of the kidney before nephrectomy. METHODS: uEVs from 5 living donors and 7 deceased donors were isolated by size-exclusion chromatography, and their protein and miRNA content were analysed by liquid chromatography followed by mass spectrometry and next generation sequencing, respectively. Then, hierarchical clustering and venn diagrams were done with Perseus software and InteractiVenn tool. Specific EVs data bases were also used for Gene Ontology analysis. RESULTS: Next generation sequencing revealed that uEVs from DDs contained less miRNAs than LDs, but most of the DD-expressed miRNAs were shared with LDs (96%). Only miR-326 (targeting the apoptotic-related Bcl2) was found significantly over-represented in LD. Focusing on the protein content, we detected a low intra-group correlation in both types of donors. Despite these differences, hierarchical clustering of either miRNA or protein data could not identify a differential profile between LDs and DDs. Of note, 90% of transplanted patients had a functional graft after a year from KTx. CONCLUSIONS: In this pilot study we found that, in normo-functional grafts, minor differences in uEVs profile could not discriminate between LDs and DDs.

Frail Patient in Hemodialysis: A New Challenge in Nephrology-Incidence in Our Area, Barcelonès Nord and Maresme.

INTRODUCTION: Labeling a patient as "frail" may be useful in assessing the prognosis and therapeutic approach. OBJECTIVE: The aim of the study is to define a pattern of frailty among our dialysis population, to analyse the incidence and clinical evolution of these patients. MATERIALS AND METHODS: We analysed a total of 320 patients with stage V chronic kidney disease (CKD) who were on hemodialysis between September 2014 and September 2015. To define a patient as frail we used the Fried phenotype model, and we added a new criteria-dialysis session length longer than 12 hours/week. RESULTS: 5.6% of the 320 patients were frail. We found statistically significant differences regarding body mass index (BMI), hemoglobin (Hgb), and serum albumin, as well as the ability to perform the basic activities of daily living (p < 0.005), ability to ambulate (p = 0.01) and perform transfers (p < 0.005). We found statistically significant differences between the two groups in terms of hospital admissions (p = 0.005) and mortality (p < 0.005). CONCLUSION: 5.6% of the study population were frail, with lower BMI, serum albumin and hemoglobin, lower capacity for basic activities of daily living, ambulation, and transference, as well as higher morbidity and mortality.

Inflammation and oxidation: do they improve after kidney transplantation? Relationship with mortality after transplantation.

Patients with chronic kidney disease (CKD) are characterized by a state of inflammation and oxidative stress that seems to improve after kidney transplantation (KT). Nevertheless, there is controversy regarding what is the best marker that better define inflammation and specially oxidative stress. OBJECTIVE: To evaluate the biomarkers which are associated with improvements in inflammation and lipid peroxidation in patients who have undergone KT. To evaluate the relationship between inflammation, lipid peroxidation and mortality in KT. PATIENTS: 196 KT (between 2003 and 2008). 67.9% men; median age: 51.9 years. Inflammation markers analyzed previous KT and 3 months after KT: c-reactive protein(CRP), interleukin 6(IL-6), tumor necrosis factor alpha(TNFα), soluble tumor necrosis factor receptor alpha(sTNFRα), soluble interleukin-2 receptor (sIL-2R). Lipid peroxidation markers analyzed: oxidized low-density lipoprotein (oxLDL) and anti-oxLDL antibodies. Calculation of glomerular filtration rate after KT: MDRD equation. RESULTS: Following KT, there is a significant decrease in CRP (p = 0.006), IL-6 (p = 0.0037), TNFα (p < 0.0001), sTNFRα (p < 0.0001) and sIL-2R (p < 0.0001), while levels of oxLDL increase after KT (p < 0.0001) and there is not a significantly difference in anti-oxLDL. 12.8% of the patients had died in 2012. These patients had higher levels of IL-6 (p = 0.011) and sTNFRα (p < 0.006) after KT and a lower MDRD (p < 0.0001), hemoglobin (p = 0.012) and albumin (p = 0.007). We observed no statistically differences in the levels of markers previous KT. Of the patients who died, the 43.5% of them had anti-oxLDL antibody levels greater than 75th percentile (P75: 3781 UI/ml, p = 0.028). In the multivariate analysis, age (OR:1.12; p = 0.0129), MDRD (OR:0.92; p = 0.013) and P75 of anti-oxLDL(OR: 5.19; p = 0.026) were independent risk factors for mortality. Independent risk factors for survival were: P75 of IL-6 (HR: 2.45; p = 0.027), oxLDL (HR:19.85; p = 0.002) and anti-oxLDL (HR: 9.55; p = 0.003). CONCLUSIONS: KT improved inflammation but not lipid oxidative state. KT patients who died had a higher inflammatory state (with higher levels of IL-6 and sTNFRα), a worse lipid oxidative state and a worse renal function 3 months after KT. Age, anti-oxLDL and renal function at 3 months after KT were independent risk factors for mortality.

Low Insulin-Like Growth Factor-1 Level in Obesity Nephropathy: A New Risk Factor?

INTRODUCTION: IGF-1 (insulin-like growth factor-1) is a hormone involved in cell growth and other important processes. In the kidney, IGF-1 has a stimulating effect, increasing the blood flow and glomerular filtration rate. Although many experimental animal studies regarding the role of IGF-1 in the kidney have been conducted, few human studies are available in the literature. Obesity is a cause of renal failure, and several glomerular lesions associated with obesity have been described. However, no studies regarding the levels of IGF-1 in morbidly obese patients with renal injury associated with obesity have been conducted. AIM: To determine the serum IGF-1 concentrations in morbidly obese patients with normal renal function but with different types of early obesity-related glomerular lesions and to evaluate the possible relationship between IGF-1 and the presence of renal lesions. METHODS: Eighty morbidly obese patients with renal biopsy, including 11 patients with no evidence of renal lesion, 17 patients with single glomerulomegaly, 21 patients with single podocyte hypertrophy, 10 patients with glomerulomegaly and podocyte hypertrophy, 5 patients with focal segmental hyalinosis, and 16 patients with increased mesangial matrix and/or mesangial proliferation, participated in this study. Biological parameters, including serum IGF-1 concentrations with the standard deviation score for age (SDS-IGF-1), were determined for all patients. RESULTS: Eighty patients (50 women and 30 men) with a mean BMI of 52.63 ± 8.71 and a mean age of 42.40 ± 9.45 years were included in this study. IGF-1, IGF-1 SDS and IGF-1BP3 levels according to the renal injury were compared (normal glomeruli: IGF-1 = 190.17 ± 72.46; glomerulomegaly: IGF-1 = 122.3 ± 50.05; podocyte hypertrophy: IGF-1 = 119.81 ± 60.34; focal segmental hyalinosis: IGF-1 170.98 ± 100.83, increased mesangial matrix and/or mesangial proliferation: IGF-1 117.73 ± 63.87). Statistically significant differences were observed between serum levels of IGF-1 and between the levels of SDS-IGF-1 by comparing the group without glomerular lesion with the group formed by patients with any type of glomerular injury. Logistic regression analysis was performed, with the dependent variable defined as the glomerular injury. In the multivariate analysis, only SDS-IGF-1 was associated with glomerular injury, and low levels of IGF-1 SDS were a risk factor for kidney injury. CONCLUSIONS: Our study demonstrates that low IGF-1 serum levels are associated with renal lesions in morbidly obese patients without overt clinical renal manifestations.

Removal of Dolutegravir by Hemodialysis in HIV-Infected Patients with End-Stage Renal Disease.

Data on dolutegravir removal by hemodialysis are lacking. To study this, we measured dolutegravir plasma concentrations in samples of blood entering and leaving the dialyzer and of the resulting dialysate from 5 HIV-infected patients with end-stage renal disease. The median dolutegravir hemodialysis extraction ratio was 7%. The dolutegravir concentrations after the dialysis session remained far above the protein-binding-adjusted inhibitory concentration. Our results show minimal dolutegravir removal by hemodialysis, with no specific dolutegravir dosage adjustments required in this setting. (This study is registered at ClinicalTrials.gov under registration number NCT02487706.).

Obliteración de la arteria ilíaca como causa de hipertensión renovascular en el paciente trasplantado renal, un diagnóstico difícil y poco frecuente / Iliac artery obliteration as a cause of renovascular hypertension in kidney graft recipients: A difficult and uncommon diagnosis

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Size-exclusion chromatography-based enrichment of extracellular vesicles from urine samples.

Renal biopsy is the gold-standard procedure to diagnose most of renal pathologies. However, this invasive method is of limited repeatability and often describes an irreversible renal damage. Urine is an easily accessible fluid and urinary extracellular vesicles (EVs) may be ideal to describe new biomarkers associated with renal pathologies. Several methods to enrich EVs have been described. Most of them contain a mixture of proteins, lipoproteins and cell debris that may be masking relevant biomarkers. Here, we evaluated size-exclusion chromatography (SEC) as a suitable method to isolate urinary EVs. Following a conventional centrifugation to eliminate cell debris and apoptotic bodies, urine samples were concentrated using ultrafiltration and loaded on a SEC column. Collected fractions were analysed by protein content and flow cytometry to determine the presence of tetraspanin markers (CD63 and CD9). The highest tetraspanin content was routinely detected in fractions well before the bulk of proteins eluted. These tetraspanin-peak fractions were analysed by cryo-electron microscopy (cryo-EM) and nanoparticle tracking analysis revealing the presence of EVs.When analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, tetraspanin-peak fractions from urine concentrated samples contained multiple bands but the main urine proteins (such as Tamm-Horsfall protein) were absent. Furthermore, a preliminary proteomic study of these fractions revealed the presence of EV-related proteins, suggesting their enrichment in concentrated samples. In addition, RNA profiling also showed the presence of vesicular small RNA species.To summarize, our results demonstrated that concentrated urine followed by SEC is a suitable option to isolate EVs with low presence of soluble contaminants. This methodology could permit more accurate analyses of EV-related biomarkers when further characterized by -omics technologies compared with other approaches.

Long-Term Normal Renal Function after Drastic Weight Reduction in Patients with Obesity-Related Glomerulopathy.

AIMS: No long-term studies of renal function evolution in morbidly obese (MO) patients after weight loss are available. The aim of our work was to ascertain the long-term influence of drastic weight reduction on renal function in MO patients with obesity-related glomerular lesions. METHODS: 92 MO patients with normal renal function and biopsy evidence of mild obesity-related glomerulopathy underwent bariatric surgery (BS) and subsequent drastic weight loss. A long-term prospective follow-up (mean duration: 76 ± 42 months) was carried out. Basal renal biopsies and basal and long-term metabolic and renal function studies were performed in all cases. Linear mixed models were applied. RESULTS: Blood pressure dropped early after BS and remained stable thereafter. Creatinine clearance and BMI fell in the first 2 years, rose slightly after 5 years and then remained stable. Serum creatinine and albuminuria decreased throughout the follow-up period. Renal function and albuminuria evolution showed non-significant differences in relation to the number of glomerular lesions. CONCLUSIONS: Drastic weight loss in BS-treated MO patients with pre-surgical normal renal function and mild obesity-related glomerular lesions is associated with short- and long-term maintenance of normal renal function and improvement in both arterial hypertension and albuminuria.

Urinary extracellular vesicles as source of biomarkers in kidney diseases.

Most cells physiologically release vesicles as way of intercellular communication. The so-called Extracellular Vesicles (EVs) include exosomes, ectosomes, and apoptotic bodies, which basically differ in their composition and subcellular origin. Specifically, EVs found in urine reflect the state of the urinary system, from podocytes to renal-tubular cells, thus making them an excellent source of samples for the study of kidney physiology and pathology. Several groups have focused on defining biomarkers of kidney-related disorders, from graft rejection to metabolic syndromes. So far, the lack of a standard protocol for EVs isolation precludes the possibility of a proper comparison among the different biomarkers proposed in the literature, stressing the need for validation of these biomarkers not only in larger cohorts of patients but also considering the different methods for EVs isolation. In this review, we aim to gather the current knowledge about EVs-related biomarkers in kidney diseases, with a special emphasis in the methods used to date for EVs enrichment, and discussing the need for more specific protocols of EV isolation in clinical practice.