Decreased serum adrenal androgen dehydroepiandrosterone sulfate and mortality in hemodialysis patients

Causality of Genetically Determined Metabolites on Chronic Kidney Disease: A Two-Sample Mendelian Randomization Study In Silico

Introduction: Chronic kidney disease (CKD) is associated with metabolic disorders. However, the evidence for the causality of circulating metabolites to promote or prevent CKD is still lacking. Methods: The two-sample Mendelian randomization (MR) analysis was conducted to evaluate the latent causal relationship between the genetically proxied 486 blood metabolites and CKD. Genome-wide association study (GWAS) data for exposures were derived from 7824 European GWAS on metabolite levels, which have been extensively utilized in the medical field to elucidate the mechanisms underlying disease onset and progression. The random inverse variance weighted (IVW) is the primary analysis for causality analysis while MR-Egger and weighted median as complementary analyses. For the further identification of metabolites, reverse MR and linkage disequilibrium score regression were performed for further evaluation. The drug target for N-acetylornithine was subsequently supplemented into the analysis, with MR and colocalization analysis being utilized. Key metabolic pathways were identified via MetaboAnalyst 4.0 (https://www.metaboanalyst.ca/) online website. Results: N-acetylornithine was identified as a reliable metabolite that increases the susceptibility to estimated glomerular filtration rate (eGFR) decrease (β = 0.047; 95% confidence interval: -0.068 to -0.026; PIVW = 1.5E-5). The "glyoxylate and dicarboxylate metabolism" pathway showed significant relevance to CKD development (P = 6E-4), whereas the "glycine, serine, and threonine metabolism" pathway was also recognized as associated with CKD by general practitioners (P = 7E-4). Colocalization analysis revealed a robust genetic link between N-acetylornithine and both CKD and eGFR, with 85.1% and 99.4% colocalization rates, respectively. IVW-MR analysis substantiated these findings with a significant positive association for CKD (odds ratio = 1.43, P = 4.7E-5) and a negative correlation with eGFR (b = -0.04, P = 1.13E-31). Conclusions: MR was utilized to explore the potential causal links between 61 genetic serum metabolites and CKD. N-acetylornithine and NAT8 were further explored as a potential therapeutic target for CKD treatment.

A Holistic Framework for the Evaluation of Kidney Function in a Gender-Diverse Landscape

The most commonly used equations to estimate glomerular filtration rate incorporate a binary male-female sex coefficient, which has important implications for the care of transgender, gender-diverse, and nonbinary (TGD) people. Whether "sex assigned at birth" or a binary "gender identity" is most appropriate for the computation of estimated glomerular filtration rate (eGFR) is unknown. Furthermore, the use of gender-affirming hormone therapy (GAHT) for the development of physical changes to align TGD people with their affirmed gender is increasingly common, and may result in changes in serum creatinine and cystatin C, the biomarkers commonly used to estimate glomerular filtration rate. The paucity of current literature evaluating chronic kidney disease (CKD) prevalence and outcomes in TGD individuals on GAHT makes it difficult to assess any effects of GAHT on kidney function. Whether alterations in serum creatinine reflect changes in glomerular filtration rate or simply changes in muscle mass is unknown. Therefore, we propose a holistic framework to evaluate kidney function in TGD people. The framework focuses on kidney disease prevalence, risk factors, sex hormones, eGFR, other kidney function assessment tools, and the mitigation of health inequities in TGD people.

Differential associations of fetuin-A and calcification propensity with cardiovascular events and subsequent mortality in patients undergoing hemodialysis

Background

Fetuin-A inhibits precipitation of calcium-phosphate crystals by forming calciprotein particles (CPP). A novel T50 test, which measures transformation time from primary to secondary CPP, is an index for calcification propensity. Both lower fetuin-A and shorter T50 levels were associated with cardiovascular disease (CVD) risk in patients with chronic kidney disease (CKD). Extremely high risk for CVD death in advanced CKD patients consists of high-incidental CVD event and high mortality after CVD event. To date, it is unclear whether fetuin-A and/or T50 can equally predict each CVD outcome.

Methods

This prospective cohort study examined patients undergoing maintenance hemodialysis. The exposures were fetuin-A and T50. The outcomes of interests were new CVD events and subsequent deaths. The patients were categorized into tertiles of fetuin-A or T50 (T1 to T3).

Results

We identified 190 new CVD events during the 5-year follow-up of the 513 patients and 59 deaths subsequent to the CVD events during 2.5-year follow-up. A lower fetuin-A but not T50 was significantly associated with new CVD events [subdistribution hazard ratio (HR) 1.73, 95% confidence interval (CI) 1.15-2.61, P = .009 for T1 vs T3]. In contrast, a shorter T50 but not fetuin-A was a significant predictor of deaths after CVD events (HR 3.31, 95% CI 1.42-7.74, P = .006 for T1 + T2 vs T3). A lower fetuin-A was predictive of new CVD events, whereas a shorter T50 was more preferentially associated with subsequent death.

Conclusion

These results indicate that fetuin-A and T50 are involved in cardiovascular risk in different manners.

Serum metabolomics analysis reveals metabolite profile and key biomarkers of idiopathic membranous nephropathy

Background

Idiopathic membranous nephropathy (IMN) is an organ-specific autoimmune disease with multiple and complex pathogenic mechanisms. Currently, renal biopsy is considered the gold standard for diagnosing membranous nephropathy. However, there were limitations to the renal puncture biopsy, such as the relatively high cost, longer time consuming, and the risk of invasive procedures. We investigated the profile of serum metabolites in IMN patients based on the UHPLC-QE-MS metabolomics technique for exploring the potential disease biomarkers and clinical implementation.

Methods

In our research, we collected serum samples from healthy control (n = 15) and IMN patients (n = 25) to perform metabolomics analysis based on the UHPLC-QE-MS technique.

Result

We identified 215 differentially expressed metabolites (DEMs) between the IMN and healthy control (HC) groups. Furthermore, these DEMs were significantly identified in histidine metabolism, arginine and proline metabolism, pyrimidine metabolism, purine metabolism, and steroid hormone biosynthesis. Several key DEMs were significantly correlated with the level of clinical parameters, such as serum albumin, IgG, UTP, and cholesterol. Among them, dehydroepiandrosterone sulfate (DHEAS) was considered the reliable diagnostic biomarker in the IMN group. There was an increased abundance of actinobacteria, phylum proteobacteria, and class gammaproteobacterial in IMN patients for host-microbiome origin analysis.

Conclusion

Our study revealed the profiles of DEMs from the IMN and HC groups. The result demonstrated that there were disorders of amino acids, nucleotides, and steroids hormones metabolism in IMN patients. The down-regulation of DHEAS may be associated with the imbalance of the immune environment in IMN patients. In host-microbiome origin analysis, the gut microbiota and metabolite disturbances were present in IMN patients.

Sex hormones and the risk of cardiovascular disease and mortality in male and female patients with chronic kidney disease: A systematic review and meta-analysis

Patients with chronic kidney disease (CKD) commonly experience sex hormone disturbances, which may be associated with the risk of cardiovascular disease (CVD) and mortality. This review aimed to systematically evaluate current findings on the association of sex hormone levels with the risk of CVD events and mortality (CVD and all-cause) in the CKD population. Articles were systematically searched in CINAHL, Cochrane, and PubMed. A total of 1739 articles were independently screened by two reviewers and 17 prospective cohort studies were included. The clinical conditions of the patients were those with non-dialysis CKD [mean/median estimated glomerular filtration rate (eGFR) between 15-51 ml/min/1.73 m2 ] and those on chronic dialysis (mean/median vintage between 6-125 months). The sample size ranged from 111 to 2419 and the mean/median age of subjects ranged from 52 to 72 years. The sex hormones studied were testosterone, estradiol, prolactin, dehydroepiandrosterone sulfate, and relaxin. A random-effects model was used to generate a pooled hazard ratio (HR) to evaluate the association of total testosterone levels with the risk of CVD and all-cause mortality. Most studies examined total testosterone levels (11 out of 17 studies) and studied only male patients (12 out of 17 studies). A lower total testosterone level was associated with a higher risk of CVD mortality [HR 4.37 (95% CI 1.40-13.65)] and all-cause mortality [1.96 (1.35-2.83)] in males with CKD. To conclude, there is a strong need for additional studies examining the association of sex hormones with cardiovascular and mortality risk in female patients with CKD.

Testosterone Deficiency and Nutritional Parameters as Predictors of All-Cause Mortality among Male Dialysis Patients

Background: Chronic kidney disease (CKD) is associated with an accelerated risk of cardiovascular mortality. Hormonal and metabolic disorders in CKD may constitute novel risk factors. Our objective was to characterize and evaluate prognostic implications of circulating sex steroids and selected nutritional parameters in patients at different stages of CKD. Methods: Studied groups were composed of 78 men: 31 on hemodialysis (HD), 17 on peritoneal dialysis (PD), 30 with CKD stage G3-G4. Total testosterone (TT), dehydroepiandrosterone sulphate (DHEA-S), androstenedione, luteinizing hormone (LH), prolactin (PRL), and biochemical parameters were measured; Free testosterone (FT) was calculated. Results: The lowest TT and FT were observed in HD, the highest- in CKD (p = 0.006 for TT, p = 0.005 for FT). TT positively correlated with total cholesterol in HD (p = 0.012), FT negatively correlated with BMI in CKD (p = 0.023). During the 12 months, 9 patients died (5 in the HD, 4 in the PD group). The deceased group had significantly lower concentrations of albumin (p = 0.006) and prealbumin (p = 0.001), and a significantly higher concentration of androstenedione (p = 0.019) than the surviving group. In the group of men on dialysis, a serum TT concentration <2.55 ng/mL (Q1-first quartile) was associated with a 3.7-fold higher risk of death, although statistical significance was not achieved (p = 0.198). After analysis of the ROC curves, the FT level was the best prognostic marker in HD (AUC = 0.788; 95% CI: 0.581−0.996; p = 0.006) Conclusions: Total and free testosterone levels were lower in the HD group than in the CKD group. The nutritional status undoubtedly affects the survival of dialysis patients but also the concentrations of testosterone significantly contributes to further worsening the prognosis.

The Relation of Serum Dehydroepiandrosterone Sulfate Level to Protein Energy Wasting in Hemodialysis Patients

Protein-energy wasting (PEW) is a major risk for morbidity and mortality in hemodialysis (HD) patients. The change in the concentration of dehydroepiandrosterone sulfate (DHEA-S) may play a role in PEW. The aim of this work was to study the possible relationship between serum DHEA-S levels and various nutritional and inflammatory parameters in a cohort of HD patients. In total, 78 HD patients (47 males and 31 females) were included in this crosssectional observational study. In addition to taking their history, clinical examinations, and routine laboratory investigations, the nutritional status was assessed, and their serum DHEA-S was measured. Nutritional status was assessed by anthropometric measures, bioelectrical impedance analysis, malnutrition inflammation scores, and subjective global assessments. A diagnosis of malnutrition was made based on the recommendations of the International Society of Renal Nutrition and Metabolism. The relationship between DHEA-S and various nutritional parameters was analyzed. Eighteen patients (23.1%) suffered from PEW. Those with PEW had a longer duration of HD (P = 0.04), and lower serum levels of creatinine (P = 0.003), hemoglobin (P = 0.01), albumin (P <0.0001), cholesterol (P = 0.02), and DHEA-S (P = 0.01). Among the variables, serum DHEA-S levels were significant predictors of PEW in this cohort (odds ratio: 0.976; 95% confidence interval: 0.954-1.0; P = 0.04). PEW is frequently encountered in HD patients. Decreased serum DHEA-S levels were associated with PEW in male HD patients. Further studies are needed to assess the effect of hormone supplementation on this serious disorder in HD patients.

Serum phosphate as an independent factor associated with cholesterol metabolism in patients undergoing hemodialysis: a cross-sectional analysis of the DREAM cohort

Background

Hyperphosphatemia is a risk factor for cardiovascular outcomes in patients with chronic kidney disease. In an experimental model, hyperphosphatemia promotes atherosclerosis by activating sterol regulatory element-binding protein 2 which controls cholesterol homeostasis. In the present study, we hypothesized that serum phosphate level is associated with cholesterol metabolism in patients with kidney failure.

Methods

We conducted a single center cross-sectional study including 492 patients undergoing hemodialysis and 100 healthy controls not on statin or ezetimibe treatment. Serum lathosterol and campesterol levels were measured as a marker of cholesterol synthesis and absorption, respectively. As compared to the control group, the hemodialysis patients had higher median (interquartile range) phosphate [5.8 (5.0 to 6.6) vs. 3.3 (3.0 to 3.6) mg/dL, P &lt; 0.001], lower lathosterol [1.2 (0.8 to 1.7) vs. 2.6 (1.9 to 3.4) µg/mL, P &lt; 0.001] and higher campesterol levels [4.5 (3.6 to 6.0) vs. 4.1 (3.2 to 5.4) µg/mL, P = 0.02]. Serum phosphate correlated positively to campesterol in the control group (Spearman's r = 0.21, P = 0.03) and in the hemodialysis patients (Spearman's r = 0.19, P &lt; 0.001). The positive association between phosphate and campesterol levels in the hemodialysis group remained significant in multivariable-adjusted linear regression analysis. There was no significant association between phosphate and lathosterol in either group.

Conclusions

An independent association was found between phosphate and campesterol levels in patients with kidney failure. This study suggests a novel relationship between phosphate and cholesterol metabolism, both of which could affect cardiovascular outcomes in this population.

The role of serum testosterone and dehydroepiandrosterone sulfate in kidney function and clinical outcomes in chronic kidney disease: a systematic review and meta-analysis

OBJECTIVE/DESIGN

Testosterone might mediate sex differences in kidney function and chronic kidney disease (CKD). However, few studies analyzing the association between testosterone and kidney function showed conflicting results. Therefore, we performed a systematic review and meta-analysis.

METHODS

Six electronic databases were searched from inception to March 4, 2020, for studies that investigated the association of (i) testosterone status with kidney function in the general population or (ii) testosterone status with clinical outcomes (kidney function decline, kidney failure, cardiovascular (CV) events, and cardiovascular and all-cause mortality) in CKD patients. We used random and fixed-effect models to obtain pooled effect estimates with 95% confidence intervals (CIs).

RESULTS

No randomized-controlled trials that met the inclusion criteria were identified. One study was conducted in the general population and reported an increased risk of incident CKD with low vs normal testosterone (hazard ratio (HR): 1.38, 95% CI: 1.05;1.80). Seven studies were conducted in men with CKD and included testosterone as determinant, of which six could be meta-analyzed. Low testosterone was associated with an increased risk of all-cause mortality and CV events (pooled HR: 1.98, 95% CI: 1.36;2.89; pooled HR of 2.40, 95% CI: 1.22;4.71, respectively). Two studies showed an increased risk of all-cause mortality with decreased dehydroepiandrosterone sulfate (DHEAS) in men with CKD; results regarding CV events were conflicting.

CONCLUSIONS

Although literature is scarce, evidence suggests that lower testosterone may increase CKD risk in the general population and risk of all-cause mortality and CV events in men with CKD. Whether testosterone supplementation could prevent these potential detrimental outcomes should be determined in future intervention studies.

Nutritional disorder evaluated by geriatric nutritional risk index predicts death after hospitalization for infection in patients undergoing maintenance hemodialysis

OBJECTIVE

Infection is related to higher rate of hospitalization and subsequent death in patients undergoing hemodialysis. Limited data are available about factors associated with death after hospitalization for infection. Nutritional disorder also known as protein-energy wasting is profoundly associated with poor consequences. Geriatric nutritional risk index (GNRI) is a simple but useful nutritional screening tool to predict mortality. We examined whether GNRI could predict hospitalization for infection and subsequent death.

DESIGN AND METHODS

This was a prospective cohort study in hemodialysis patients. The predictor was GNRI. The patients were divided into tertiles of GNRI (T1 to T3), with the highest tertile of T3 as referent. The outcomes of interest were all-cause mortality, hospitalization for infection and subsequent death.

RESULTS

Of 518 patients, 107 patients died (median follow-up period, 5.0 years; interquartile range 3.6-5.0) and 169 patients experienced new hospitalization for infection (median follow-up period, 4.5 years; interquartile range 3.4-5.0) during the follow-up period from December 2004 to December 2009. A lower GNRI was a significant predictor for all-cause mortality in multivariable Cox models (hazard ratio [HR] 2.9, 95% confidential interval [CI] 1.5-5.5, p < 0.001 for T1 vs. T3). However, GNRI was not associated with hospitalization for infection in multivariable Fine-Gray models with death as a competing risk (subdistributional HR 1.5, 95% CI 1.0-2.3, p = 0.056 for T1 vs. T3). After hospitalization for infection, 38 patients died during subsequent 2.5-year follow-up period. GNRI was a significant predictor of death after hospitalization for infection in multivariable Cox models (HR 2.7, 95% CI 1.3-5.6, p = 0.006 for T1 vs. T2+T3).

CONCLUSIONS

A lower GNRI predicted a higher risk of all-cause mortality but not hospitalization for infection. However, a lower GNRI was significantly associated with a higher risk of mortality after hospitalization for infection. These findings suggest that long-term mortality after hospitalization for infection was predicted by nutritional disorder evaluated by GNRI.

Associations of Serum Insulin-Like Growth Factor 1 with New Cardiovascular Events and Subsequent Death in Hemodialysis Patients: The DREAM Cohort

Aim: Patients with chronic kidney disease (CKD) have elevated risk of death from cardiovascular disease (CVD). A low serum insulin-like growth factor 1 (IGF-1) level is known to predict higher risk for all-cause mortality in incident dialysis patients, although it is unknown whether IGF-1 predicts cardiovascular outcomes.

Methods: This was a prospective cohort study of maintenance hemodialysis patients followed up for 5 years. Serum IGF-1 levels were measured at baseline, and patients were divided into IGF-1 tertiles. The key outcomes were all-cause mortality, a composite of new CVD, and death after new CVD events. Additional outcomes were hospitalization for infection and subsequent death. Association was analyzed using Cox proportional hazards models.

Results: In the 516 patients that were analyzed, we identified 106 all-cause deaths, 190 new CVD events, and 61 subsequent deaths. In addition, there were 169 hospitalizations for infection and 47 subsequent deaths. The risk of all-cause death was the highest in the lowest IGF-1 tertile, and this association remained significant in multivariable-adjusted models. Regarding CVD outcomes, IGF-1 was not associated with new CVD events but significantly associated with subsequent death in adjusted models. Similarly, IGF-1 was not an independent predictor of hospitalization for infection, but it predicted subsequent death.

Conclusions: A low IGF-1 level was not a significant predictor of new CVD events but an independent predictor of subsequent death in hemodialysis patients. Since similar associations with infection outcomes were observed, IGF-1 may be a biomarker of fragility or frailty in this population.

Relationship between sex and cardiovascular mortality in chronic kidney disease: A systematic review and meta-analysis

Chronic kidney disease (CKD) is a significant health challenge associated with high cardiovascular mortality risk. Historically, cardiovascular mortality risk has been found to higher in men than women in the general population. However, recent research has highlighted that this risk may be similar or even higher in women than men in the CKD population. To address the inconclusive and inconsistent evidence regarding this relationship between sex and cardiovascular mortality within CKD patients, a systematic review and meta-analysis of articles published between January 2004 and October 2020 using PubMed/Medline, EMBASE, Scopus and Cochrane databases was performed. Forty-eight studies were included that reported cardiovascular mortality among adult men relative to women with 95% confidence intervals (CI) or provided sufficient data to calculate risk estimates (RE). Random effects meta-analysis of reported and calculated estimates revealed that male sex was associated with elevated cardiovascular mortality in CKD patients (RE 1.13, CI 1.03-1.25). Subsequent subgroup analyses indicated higher risk in men in studies based in the USA and in men receiving haemodialysis or with non-dialysis-dependent CKD. Though men showed overall higher cardiovascular mortality risk than women, the increased risk was marginal, and appropriate risk awareness is necessary for both sexes with CKD. Further research is needed to understand the impact of treatment modality and geographical distribution on sex differences in cardiovascular mortality in CKD.

Coincidence of Large Adrenal Cyst and Prominent Hyporeninemic Hyperaldosteronism

A 67-year-old Japanese woman who had end-stage renal disease was referred to our hospital for kidney transplantation. Abdominal CT revealed a large adrenal mass with inhomogeneity. She had a history of hospitalization for stroke and heart failure and exhibited prominent hyporeninemic hyperaldosteronism. Histological examination of the resected tumor with anti-CYP11B2 antibody indicated that she had a vascular endothelial cyst with primary aldosteronism (PA) due to multiple adrenocortical micronodules. This report implicates the pathological interaction between adrenal vascular cysts and PA-mediated vascular damage of the adrenal vein.

Low Free Triiodothyronine Level as a Predictor of Cardiovascular Events and All-Cause Mortality in Patients Undergoing Hemodialysis: The DREAM Cohort

AIM

Low T3 syndrome is characterized by low serum triiodothyronine (T3) levels without elevation of thyroid-stimulating hormone (TSH) in patients without apparent thyroid disease, which is known to be associated with worse clinical outcomes in various populations including those with kidney failure. In this study, we examined whether low free T3 (FT3) levels are independent predictor of cardiovascular disease (CVD) events in patients undergoing hemodialysis.

METHODS

This was a prospective cohort study of patients with chronic kidney disease undergoing hemodialysis. From the total of 518 patients, we excluded patients with treated or untreated hyperthyroidism or hypothyroidism and those treated with corticosteroids.

RESULTS

We analyzed data from 438 eligible patients. During the 5-year follow-up, 154 new CVD events and 86 all-cause deaths were recorded. Kaplan-Meier analysis showed that lower FT3 levels were associated with higher risks for new cardiovascular events and all-cause death. This inverse association of FT3 and new CVD events remained significant after adjustment for age, sex, duration of hemodialysis, diabetic kidney disease, hypertension, dyslipidemia, and smoking; however, it was no longer significant after further adjustment for prior CVD or N-terminal fragment of probrain natriuretic peptide (NT-proBNP). FT3 did not show an independent association with all-cause mortality.

CONCLUSIONS

Our results indicate that low FT3 status is not an independent predictor of new CVD events and that the following factors are closely associated: prior CVD, low FT3 and high NT-proBNP levels at present, and future risk of new CVD events in hemodialysis patients.

Oxidative Stress and Inflammation as Predictors of Mortality and Cardiovascular Events in Hemodialysis Patients: The DREAM Cohort

Aim: Both oxidative stress and inflammation are involved in the pathogenesis of cardiovascular disease (CVD). The serum level of derivatives of reactive oxygen metabolites (d-ROMs) is a measure of the total amount of hydroperoxides serving as a marker of oxidative stress. We investigated whether d-ROMs could predict the clinical outcomes in hemodialysis patients and whether the associations of d-ROMs with the outcomes are independent of a marker of inflammation, C-reactive protein (CRP).

Methods: This was a prospective cohort study in hemodialysis patients. The key exposures were the serum levels of d-ROMs and CRP. The outcome measures were all-cause mortality and new CVD events.

Results: A total of 517 patients were analyzed. d-ROMs correlated positively with CRP. During follow-up for 5 years, 107 patients died, and 190 patients experienced new CVD events. In the Kaplan–Meier analyses, both higher d-ROMs and higher CRP levels predicted higher risks for mortality and CVD events. By Cox proportional-hazard regression analysis adjusted for potential confounders excluding CRP, d-ROMs exhibited a significant association with all-cause mortality, but this association was no longer significant after further adjustment for CRP. Using the same model, CRP exhibited a significant association with all-cause mortality, but this association was no longer significant after further adjustment for d-ROMs. When we analyzed new CVD events as the outcome, CRP was a significant predictor, whereas the level of d-ROMs was not.

Conclusions: Although d-ROMs predicted mortality and CVD events in unadjusted models, the associations of d-ROMs with these outcomes were not independent of CRP. Oxidative stress and inflammation appear to share common causal pathways.

Association between Plasma Dehydroepiandrosterone Sulfate and Carotid Intima-Media Thickness among Male and Female Patients with End-Stage Renal Disease on Hemodialysis

BACKGROUND AND AIM

Serum dehydroepiandrosterone sulfate (DHEA-S) is known to be lower in chronic kidney disease (CKD) patients and in those with cardiac disease, and correlates with a poor cardiovascular outcome. This study aimed to assess the correlation between DHEA-S and carotid intima-media thickness (CIMT) as a predictor of cardiovascular disease in hemodialysis (HD) patients.

METHODS

A total of 88 HD patients were included in this cross-sectional study. They included 53 male (group I) and 35 female patients (group II). In addition to conventional history taking, clinical examination, and routine laboratory investigations, serum DHEA-S and CIMT were measured for all patients. CIMT was measured using B-mode ultrasonography, and the mean of maximum CIMT was recorded. The 2 patient groups were further classified according to the level of DHEA-S. The correlation between serum DHEA-S and CIMT was studied.

RESULTS

In male patients, CIMT and age were significantly higher in the group with low DHEA-S level (p = 0.003 and 0.001, respectively), while there was no significant difference in both parameters in females. A higher percentage of HCV-positive patients is present in the male group with low DHEA-S level (p = 0.009). Serum DHEA-S is significantly negatively correlated with CIMT in males (p = 0.003) but not in females, and has a significant negative correlation to age in both genders (p = 0.001 and 0.04, respectively).

CONCLUSION

Endocrinal disturbance representing as lower serum DHEA-S is associated with increased CIMT, which is considered a predictor of cardiovascular disease in male HD patients, although it is largely explained by advancing age.

Mechanisms of Action of Dehydroepiandrosterone

Dehydroepiandrosterone (3β-hydroxy-5-androsten-17-one, DHEA) and its sulfated metabolite DHEA-S are the most abundant steroids in circulation and decline with age. Rodent studies have shown that DHEA has a wide variety of effects on liver, kidney, adipose, reproductive tissues, and central nervous system/neuronal function. The mechanisms by which DHEA and DHEA-S impart their physiological effects may be direct actions on plasma membrane receptors, including a DHEA-specific, G-protein-coupled receptor in endothelial cells; various neuroreceptors, e.g., aminobutyric-acid-type A, N-methyl-d-aspartate (NMDA), and sigma-1 (S1R) receptors; by binding steroid receptors: androgen and estrogen receptors (ARs, ERα, or ERβ); or by their metabolism to more potent sex steroid hormones, e.g., testosterone, dihydrotestosterone, and estradiol, which bind with higher affinity to ARs and ERs. DHEA inhibits voltage-gated T-type calcium channels. DHEA activates peroxisome proliferator-activated receptor (PPARα) and CAR by a mechanism apparently involving PP2A, a protein phosphatase dephosphorylating PPARα and CAR to activate their transcriptional activity. We review our recent study showing DHEA activated GPER1 (G-protein-coupled estrogen receptor 1) in HepG2 cells to stimulate miR-21 transcription. This chapter reviews some of the physiological, biochemical, and molecular mechanisms of DHEA and DHEA-S activity.

Altered Serum n-6 Polyunsaturated Fatty Acid Profile and Risks of Mortality and Cardiovascular Events in a Cohort of Hemodialysis Patients

OBJECTIVE

Alterations in the balance between serum n-3 and n-6 polyunsaturated fatty acids (PUFAs) is predictive of cardiovascular events among hemodialysis patients, although little is known about the serum ratio of n-6 arachidonic acid (AA) to n-6 dihomo-γ-linoleic acid (DGLA) in renal failure. We hypothesized that AA/DGLA ratio is altered in hemodialysis patients resulting in poor clinical outcomes.

METHODS

This was a single center cohort study in an urban area in Japan with cross-sectional analyses. Subjects were 517 hemodialysis patients and 122 control subjects. The main exposure was serum AA/DGLA ratio, and the main outcome measures were all-cause mortality and cardiovascular events during 5 years.

RESULTS

The hemodialysis patients showed a higher median (interquartile range) AA/DGLA ratio than the control subjects (6.46 [5.22-7.81] versus 4.56 [3.74-6.34], P < .001). In a Cox proportional hazard model adjusted for age, sex, dialysis duration, diabetic nephropathy, prior cardiovascular disease, and the ratio of serum n-3 polyunsaturated fatty acids (eicosapentaenoic acid plus docosahexaenoic acid) to AA, the higher quartiles of AA/DGLA ratio were associated with higher risk for all-cause mortality with hazard ratios (95% confidence interval) of 1.50 (0.84-2.76) for quartile 2, 2.10 (1.18-3.86) for quartile 3, and 2.02 (1.10-3.78) for quartile 4 compared with quartile 1. AA/DGLA ratio showed a similar association with the risk of cardiovascular events.

CONCLUSIONS

AA/DGLA ratio was elevated in patients with end-stage renal disease requiring hemodialysis, and a high AA/DGLA ratio was an independent predictor of poor clinical outcomes in this population.

Association between Testosterone and Mortality Risk among U.S. Males Receiving Dialysis

BACKGROUND

Among the general population, low circulating testosterone levels are associated with higher risk of cardiovascular disease and death. While testosterone deficiency is common in dialysis patients, studies of testosterone and mortality in this population are ambiguous and overlapping. We hypothesized that lower testosterone levels are associated with higher mortality in male dialysis patients.

METHODS

We examined a nationally representative cohort of male dialysis patients from a large US dialysis organization who underwent one or more total testosterone measurements from 1/2007 to 12/2011. The association between total testosterone categorized as quartiles and all-cause mortality was studied using Cox models adjusted for expanded case-mix and laboratory covariates. We also examined total testosterone as a continuous predictor of all-cause mortality using restricted cubic splines.

RESULTS

Among 624 male dialysis patients, 51% of patients demonstrated testosterone deficiency (total testosterone <300 ng/dL); median (IQR) total testosterone levels were 297 (190-424) ng/mL. In expanded case-mix + laboratory adjusted Cox analyses, we observed a graded association between lower testosterone levels and higher mortality risk (ref: quartile 3): adjusted hazard ratios (95% CI) 2.32 (1.33-4.06), 1.80 (0.99-3.28), and 0.68 (0.32-1.42) for Quartiles 1, 2, and 4, respectively. In adjusted spline analyses, the lower testosterone-higher mortality risk association declined with higher testosterone levels until the value reached a threshold of 400 ng/dL above which risk plateaued.

CONCLUSION

Lower testosterone levels were independently associated with higher mortality risk in male dialysis patients. Further studies are needed to determine underlying mechanisms, and whether testosterone replacement ameliorates death risk in this population.

Hormonal changes in hemodialysis patients: Novel risk factors for mortality?

Patients with end-stage renal disease undergoing dialysis commonly experience derangements in the hypothalamic-pituitary-gonadal axis together with alterations at the level of synthesis and clearance of many hormones. This hormonal imbalance, even if asymptomatic, has recently been associated with increased mortality in these patients. In this review, we summarize observational and mechanistic evidence linking hormonal alterations at the level of the thyroid and sex-hormone systems with this mortality risks.

Cardiothoracic Ratio as a Predictor of Cardiovascular Events in a Cohort of Hemodialysis Patients

AIM

The cardiothoracic ratio (CTR) on a chest X-ray is an indicator of cardiac enlargement, although its predictive power for cardiovascular disease (CVD) events in chronic kidney disease is unknown. We examined it in a cohort of hemodialysis patients, as compared with an N-terminal fragment of probrain natriuretic peptide (NT-proBNP).

METHOD

This was an observational study with cross-sectional and longitudinal analyses including 517 maintenance hemodialysis patients and 122 healthy control subjects. The main predictors were CTR and serum NT-proBNP, and the main outcome was CVD events in 5 years.

RESULTS

At baseline, the hemodialysis patients had higher median (interquartile range) levels of CTR [0.487 (0.457-0.520)] than the control group [0.458 (0.432-0.497)]. In the hemodialysis group, CTR was positively correlated with NT-proBNP (Spearman's r=0.44, P＜0.001). During follow-up, 190 CVD events occurred. CTR was significantly associated with the risk of CVD [HR 2.12 (95% CI, 1.38-3.25) for the fourth quartile as compared with the second quartile of CTR] in a multivariate Cox model. In the same model, NT-proBNP (fourth versus first quartile) showed a HR of 3.27 (2.02-5.31). When CTR and NT-proBNP were simultaneously included as predictors, only NT-proBNP remained a significant predictor of CVD events, all-cause mortality and composite of CVD plus all-cause mortality.

CONCLUSIONS

We showed that CTR was a significant and independent predictor of CVD in hemodialysis patients. CTR can be used for CVD risk stratification in hemodialysis patients when NT-proBNP is not available.

Sex steroids levels in chronic kidney disease and kidney transplant recipients: associations with disease severity and prediction of mortality

OBJECTIVE

Our objective was to characterize and evaluate prognostic implications of circulating sex steroids in patients at different stages of chronic kidney disease (CKD).

DESIGN

Prospective observational cohort study.

PATIENTS

We prospectively recruited patients with CKD III-IV, undergoing chronic dialysis and kidney transplant recipients (KTR) from a single centre in 2003-2004.

MEASUREMENTS

Two stored samples taken 3 months apart were analysed for sex hormones using liquid chromatography/tandem mass spectrometry, and the mean of the two was used for analysis. We also measured novel biomarkers troponin T and NT-proBNP. Patients were followed until death, transplant or 30 June 2013, and survival analysis performed.

RESULTS

In males, but not in females, both testosterone (P = 0·003) as well as oestradiol (P < 0·02) levels were lowest in dialysis patients and highest in KTR. Over a median follow up of 8·5 years (interquartile range 3·8-9·2), 52 men (36%) died and 24 (17%) received a kidney transplant. In Cox proportional hazards regression up to 9·6 years, an increase in total testosterone of 1 nmol/l was associated with a 9·8% (95% confidence interval 3·1-16·3) decrease in mortality independent of age, body mass index, stage of renal disease and circulating levels of NT-proBNP or troponin T. By contrast, sex steroid levels were not associated with mortality in females.

CONCLUSIONS

Testosterone levels differ across stages of kidney disease and low testosterone levels predict mortality in males, independent of established and novel predictors of mortality.

Clinical significance of decreased protein expression of dehydroepiandrosterone sulfate in the development of depression: a meta-analysis

BACKGROUND

Previous evidence has shown that adrenal androgens, dehydroepiandrosterone (DHEA) and its sulfate derivative (DHEAS) have significant functions related to the control of mood, affect, and anxiety. Changes in their expression levels are reportedly related to several psychiatric disorders. The objective of this meta-analysis was to explore the role of DHEAS protein expression in patients with depression.

METHOD

Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, China BioMedicine (CBM) and China National Knowledge Infrastructure (CNKI) were electronically searched. Only those studies that analyzing DHEAS expression in depression patients were considered eligible for inclusion. Standardized mean differences (SMDs) were pooled with a 95% confidence interval (CI) in accordance with the random-effects model.

RESULTS

Ten clinical case-control studies, consisting of 4496 subjects (493 patients with depression and 4003 healthy controls) were incorporated for analysis. Results revealed a lower DHEAS protein expression level in patients with depression than in normal controls (SMD=0.17, 95% CI: 0.06-0.27, P=0.002). Ethnicity-stratified analysis indicated that lower levels of DHEAS expression in depression patients were not observed in Caucasians or Asians (both P>0.05).

CONCLUSION

Elevated DHEAS protein expression may be correlated with the biological pathophysiology of depression, indicating that checking DHEAS levels and administration of DHEAS could contribute to the effective treatment of depression.

Serum n-3 and n-6 polyunsaturated fatty acid profile as an independent predictor of cardiovascular events in hemodialysis patients

BACKGROUND

Unlike the n-6 polyunsaturated fatty acid (PUFA) arachidonic acid (AA), n-3-PUFAs such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) appear to have beneficial effects on inflammation, thrombosis, and cardiovascular disease (CVD). We examined possible alterations in serum PUFA profiles in patients on maintenance hemodialysis therapy and its association with CVD risk.

STUDY DESIGN

An observational study including cross-sectional and longitudinal analyses.

SETTING & PARTICIPANTS

Single-center study of 517 maintenance hemodialysis patients in an urban area in Japan.

PREDICTORS

Serum EPA, DHA, and AA concentrations and EPA:AA, DHA:AA, and (EPA+DHA):AA ratios.

OUTCOMES

CVD events, including ischemic heart disease, stroke, peripheral artery disease, pulmonary edema, and valve disease.

RESULTS

Hemodialysis patients showed lower (EPA+DHA):AA, EPA:AA, and DHA:AA ratios than 122 controls similar in age and sex. During follow-up, 190 CVD events were recorded. (EPA+DHA):AA ratio was not associated significantly with CVD in unadjusted analysis, but was associated significantly and inversely with CVD in Cox models adjusted for age and other confounding variables, with HRs in the range of 1.71-1.99 in the lowest versus highest quartile of (EPA+DHA):AA ratios. Similarly, EPA:AA and DHA:AA ratios showed inverse associations with CVD, whereas serum EPA, DHA, and AA concentrations were not predictive of CVD.

LIMITATIONS

No information for dietary intake, use of dietary supplements, or cell membrane PUFA content.

CONCLUSIONS

In hemodialysis patients, serum PUFA profile is unfavorably altered, and the low n-3-PUFA:AA ratios are independent predictors of CVD.