Epigenetic clocks indicate that kidney transplantation and not dialysis mitigate the effects of renal ageing.

BACKGROUND: Chronic kidney disease (CKD) is an age-related disease that displays multiple features of accelerated ageing. It is currently unclear whether the two treatment options for end-stage kidney disease (dialysis and kidney transplantation [KT]) ameliorate the accelerated uremic ageing process. METHODS: Data on clinical variables and blood DNA methylation (DNAm) from CKD stage G3-G5 patients were used to estimate biological age based on blood biomarkers (phenotypic age [PA], n = 333), skin autofluorescence (SAF age, n = 199) and DNAm (Horvath, Hannum and PhenoAge clocks, n = 47). In the DNAm cohort, we also measured the change in biological age 1 year after the KT or initiation of dialysis. Healthy subjects recruited from the general population were included as controls. RESULTS: All three DNAm clocks indicated an increased biological age in CKD G5. However, PA and SAF age tended to produce implausibly large estimates of biological age in CKD G5. By contrast, DNAm age was 4.9 years (p = 0.005) higher in the transplantation group and 5.9 years (p = 0.001) higher in the dialysis group compared to controls. This age acceleration was significantly reduced 1 year after KT, but not after 1 year of dialysis. CONCLUSIONS: Kidney failure patients displayed an increased biological age as estimated by DNAm clocks compared to population-based controls. Our results suggest that KT, but not dialysis, partially reduces the age acceleration.

Phenylacetylglutamine and trimethylamine N-oxide: Two uremic players, different actions.

BACKGROUND: Chronic kidney disease (CKD) patients exhibit a heightened cardiovascular (CV) risk which may be partially explained by increased medial vascular calcification. Although gut-derived uremic toxin trimethylamine N-oxide (TMAO) is associated with calcium-phosphate deposition, studies investigating phenylacetylglutamine's (PAG) pro-calcifying potential are missing. METHODS: The effect of TMAO and PAG in vascular calcification was investigated using 120 kidney failure patients undergoing living-donor kidney transplantation (LD-KTx), in an observational, cross-sectional manner. Uremic toxin concentrations were related to coronary artery calcification (CAC) score, epigastric artery calcification score, and markers of established non-traditional risk factors that constitute to the 'perfect storm' that drives early vascular aging in this patient population. Vascular smooth muscle cells were incubated with TMAO or PAG to determine their calcifying effects in vitro and analyse associated pathways by which these toxins may promote vascular calcification. RESULTS: TMAO, but not PAG, was independently associated with CAC score after adjustment for CKD-related risk factors in kidney failure patients. Neither toxin was associated with epigastric artery calcification score; however, PAG was independently, positively associated with 8-hydroxydeoxyguanosine. Similarly, TMAO, but not PAG, promoted calcium-phosphate deposition in vitro, while both uremic solutes induced oxidative stress. CONCLUSIONS: In conclusion, our translational data confirm TMAO's pro-calcifying effects, but both toxins induced free radical production detrimental to vascular maintenance. Our findings suggest these gut-derived uremic toxins have different actions on the vessel wall and therapeutically targeting TMAO may help reduce CV-related mortality in CKD.

Interleukin-6-to-Albumin Ratio as a Superior Predictor of Mortality in End-Stage Kidney Disease Patients.

INTRODUCTION: In patients with chronic kidney disease (CKD), high interleukin-6 (IL-6) and low albumin circulating concentrations are associated with worse outcomes. We examined the IL-6-to-albumin ratio (IAR) as a predictor of risk of death in incident dialysis patients. METHODS: In 428 incident dialysis patients (median age 56 years, 62% men, 31% diabetes mellitus, 38% cardiovascular disease [CVD]), plasma IL-6 and albumin were measured at baseline to calculate IAR. We compared the discrimination of IAR with other risk factors for predicting 60-month mortality using receiver operating characteristic curve (ROC) and analyzed the association of IAR with mortality using Cox regression analysis. We divided patients into IAR tertiles and analyzed: (1) cumulative incidence of mortality and the association of IAR with mortality risk in Fine-Gray analysis, taking kidney transplantation as competing risk and (2) the restricted mean survival time (RMST) to 60-month mortality and differences of RMST (∆RMST) between IAR tertiles to describe quantitative differences of survival time. RESULTS: For all-cause mortality, the area under the ROC curve (AUC) for IAR was 0.700, which was greater than for IL-6 and albumin separately, while for CV mortality, the AUC for IAR (0.658) showed negligible improvement over IL-6 and albumin separately. In Cox regression analysis, IAR was significantly associated with all-cause mortality but not with CV mortality. Both high versus low and middle versus low tertiles of IAR associated with higher risk of all-cause mortality, subdistribution hazard ratio of 2.22 (95% CI 1.40-3.52) and 1.85 (95% CI 1.16-2.95), respectively, after adjusting for age, sex, diabetes mellitus, CVD, smoking, and estimated glomerular filtration rate. ∆RMST at 60 months showed significantly shorter survival time in middle and high IAR tertiles compared with low IAR tertile for all-cause mortality. CONCLUSIONS: Higher IAR was independently associated with significantly higher all-cause mortality risk in incident dialysis patients. These results suggest that IAR may provide useful prognostic information in patients with CKD.

The effect of high-dose vitamin D supplementation on hepcidin-25 and erythropoiesis in patients with chronic kidney disease.

BACKGROUND: Hepcidin is considered to play a central role in the pathophysiology of renal anemia. Recent studies in healthy individuals have demonstrated a suppressive effect of vitamin D (VD) on the expression of hepcidin. In this post-hoc analysis based on a randomized controlled study, we evaluated the effect of supplementing chronic kidney disease (CKD) patients (stage G3-G4) with a high daily dose of native VD on serum levels of hepcidin-25, the hepcidin/ferritin ratio, as well as on markers of erythropoiesis. METHODS: Patients with CKD stage G3-G4 included in a double blind, randomized, placebo (PBO) controlled study with available hepcidin measurements were analyzed. Study subjects received either 8000 international units (IU) of cholecalciferol daily or PBO for 12 weeks. We evaluated the change in markers of hepcidin expression, erythropoiesis, and iron status from baseline to week 12 and compared the change between the groups. RESULTS: Eighty five patients completed the study. Calcitriol, but not 25-hydroxyvitamin D (25(OH) D), was inversely correlated with serum levels of hepcidin-25 (rho = -0,38; p = < 0, 01 and rho = -0,02; p = 0, 89, respectively) at baseline. Supplementation with VD significantly raised the serum concentration of serum 25(OH)D in the treatment group (from 54 (39-71) to 156 (120-190) nmol/L; p = < 0, 01)) but had no effect on any of the markers of hepcidin, erythropoiesis, or iron status in the entire cohort. However, we did observe an increase in hemoglobin (HB) levels and transferrin saturation (TSAT) as compared to the PBO group in a subgroup of patients with low baseline 25(OH)D levels (< 56 nmol/L). In contrast, in patients with high baseline 25(OH)D values (≥ 56 nmol/L), VD supplementation associated with a decrease in HB levels and TSAT (p = 0,056) within the VD group in addition to a decrease in hepcidin levels as compared to the PBO group. CONCLUSION: High-dose VD supplementation had no discernible effect on markers of hepcidin or erythropoiesis in the entire study cohort. However, in patients with low baseline 25(OH)D levels, high-dose VD supplementation associated with beneficial effects on erythropoiesis and iron availability. In contrast, in patients with elevated baseline 25(OH)D levels, high-dose VD supplementation resulted in a decrease in hepcidin levels, most likely due to a deterioration in iron status.

Low-Plasma Insulin-Like Growth Factor-1 Associates With Increased Mortality in Chronic Kidney Disease Patients With Reduced Muscle Strength.

OBJECTIVES: Chronic kidney disease (CKD) leads to metabolic and nutritional abnormalities including resistance to insulin-like growth factor-1 (IGF-1) action, and reduced muscle mass and strength. Low IGF-1 as well as low hand-grip muscle strength (HGS) are independent predictors of increased mortality in CKD patients. METHODS: In 685 patients (CKD Stage 3-5, median age 58 years; 62% men), baseline measurements of IGF-1, HGS, subjective global assessment (SGA), lean body mass index (LBMI), and metabolic and inflammatory biomarkers potentially linked to IGF-1 were analyzed in relation to mortality during 5 years of follow-up. We compared survival in 4 groups with high or low (cut-offs defined by receiver operating characteristic curve analysis) levels of IGF-1 and HGS. RESULTS: Patients with low IGF-1 were older; had lower BMI, HGS, and LBMI, were more likely to have diabetes, cardiovascular disease (CVD), and malnutrition (SGA >1); and had high-sensitivity C-reactive protein levels. During 5 years of follow-up, 208 patients died. The mortality rate was highest among patients with Low IGF-1 + Low HGS. In competing-risk regression analysis, Low IGF-1 + Low HGS was independently associated with 2.8 times higher all-cause mortality risk than Low IGF-1 + High HGS, after adjusting for Framingham's CVD risk score, presence of CVD, SGA, dialysis status, high-sensitivity C-reactive protein, albumin, LBMI, and sample time in freezer. CONCLUSION: Low IGF-1 was associated with increased all-cause mortality in patients who also had low HGS but not in those with high HGS, suggesting that the association of IGF-1 with survival in CKD patients depends on nutritional status.

Decreasing incidence of knee arthroscopy in Sweden between 2002 and 2016: a nationwide register-based study.

BACKGROUND AND PURPOSE: Several randomized trials have demonstrated the lack of effect of arthroscopic lavage as treatment for knee osteoarthritis (OA). These results have in turn resulted in a change in Swedish guidelines and reimbursement. We aimed to investigate the use of knee arthroscopies in Sweden between 2002 and 2016. Patient demographics, regional differences, and the magnitude of patients with knee OA undergoing knee arthroscopy were also analyzed. PATIENTS AND METHODS: Trends in knee arthroscopy were investigated using the Swedish Hospital Discharge Register (SHDR) to conduct a nationwide register-based study including all adults (>18 years of age) undergoing any knee arthroscopy between 2002 and 2016. RESULTS: The total number of knee arthroscopies performed during the studied period was 241,055. The annual surgery rate declined in all age groups, for males and females as well as patients with knee OA. The incidence dropped from 247 to 155 per 105 inhabitants. Over 50% of arthroscopies were performed in metropolitan regions. CONCLUSION: We showed a dramatic decline in knee arthroscopy. There is variability in the surgery rate between males and females and among the regions of Sweden.

Scoring of medial arterial calcification predicts cardiovascular events and mortality after kidney transplantation.

BACKGROUND: Progression of vascular calcification causes cardiovascular disease, which is the most common cause of death in chronic kidney failure and after kidney transplantation (KT). The prognostic impact of the extent of medial vascular calcification at KT is unknown. METHODS: In this prospective cohort study, we investigated the impact of medial calcification compared to a mix of intimal and medial calcification represented by coronary artery calcification (CAC score) and aortic valve calcification in 342 patients starting on kidney failure replacement therapy. The primary outcomes were cardiovascular events (CVE) and death. The median follow-up time was 6.4 years (interquartile range 3.7-9.6 years). Exposure was CAC score and arteria epigastrica medial calcification scored as none, mild, moderate, or severe by a pathologist at time of KT (n = 200). We divided the patients according to kidney failure replacement therapy during follow-up, that is, living donor KT, deceased donor KT, or dialysis. RESULTS: Moderate to severe medial calcification in the arteria epigastrica was associated with higher mortality (p = 0.001), and the hazard ratio for CVE was 3.1 (95% confidence interval [CI] 1.12-9.02, p < 0.05) compared to no or mild medial calcification. The hazard ratio for 10-year mortality in the dialysis group was 33.6 (95% CI, 10.0-113.0, p < 0.001) compared to living donor recipients, independent of Framingham risk score and prevalent CAC. CONCLUSION: Scoring of medial calcification in the arteria epigastrica identified living donor recipients as having 3.1 times higher risk of CVE, independent of traditional risk factors. The medial calcification score could be a reliable method to identify patients with high and low risk of CVE and mortality following KT.

Increased Monocyte/Lymphocyte Ratio as Risk Marker for Cardiovascular Events and Infectious Disease Hospitalization in Dialysis Patients.

INTRODUCTION: In dialysis patients, cardiovascular disease (CVD) and infectious disease contribute to poor clinical outcomes. We investigated if a higher monocyte/lymphocyte ratio (MLR) is associated with an increased risk of CVD events and infectious disease hospitalizations in incident dialysis patients. METHODS: In an ongoing observational prospective cohort study, 132 Japanese dialysis patients (age 58.7 ± 11.7 years; 70% men) starting dialysis therapy were enrolled and followed up for a median of 48.7 months. Laboratory biomarkers, including white blood cell count and its differential count, were determined at baseline. Event-free time and relative risks (RRs) were calculated using the Kaplan-Meier curves and Cox models, respectively. RESULTS: When divided into 2 groups according to median MLR (0.35 [range, 0.27-0.46]), the periods without CVD events were significantly shorter in the high MLR group than in the low MLR group (log-rank test = 5.60, p = 0.018). The RR of CVD events, after adjusting for age, sex, and diabetes, was 2.43 (1.22-4.84) in the high MLR group compared to the low MLR group. The periods without infections requiring hospitalization were also shorter (log-rank test = 4.16, p = 0.041). The RR of infections requiring hospitalization was 1.98 (1.02-3.83) after the same adjustments. The number of CVD events was higher in the high MLR group (18.6 events per 100 person-years at risk [pyr]) than the low MLR group (11.1 events per 100 pyr). The duration of infectious disease hospitalization was longer in the high MLR group (6.3 days per pyr) than in the low MLR group (2.8 days per pyr). CONCLUSION: A higher MLR is associated with increased risks of both CVD events and infectious disease hospitalization in dialysis patients.

First-year mortality in incident dialysis patients: results of the Peridialysis study.

BACKGROUND: Controversy surrounds which factors are important for predicting early mortality after dialysis initiation (DI). We investigated associations of predialysis course and circumstances affecting planning and execution of DI with mortality following DI. METHODS: Among 1580 patients participating in the Peridialysis study, a study of causes and timing of DI, we registered features of predialysis course, clinical and biochemical data at DI, incidence of unplanned suboptimal DI, contraindications to peritoneal dialysis (PD) or hemodialysis (HD), and modality preference, actual choice, and cause of modality choice. Patients were followed for 12 months or until transplantation. A flexible parametric model was used to identify independent factors associated with all-cause mortality. RESULTS: First-year mortality was 19.33%. Independent factors predicting death were high age, comorbidity, clinical contraindications to PD or HD, suboptimal DI, high eGFR, low serum albumin, hyperphosphatemia, high C-reactive protein, signs of overhydration and cerebral symptoms at DI. Among 1061 (67.2%) patients who could select dialysis modality based on personal choice, 654 (61.6%) chose PD, 368 (34.7%) center HD and 39 (3.7%) home HD. The 12-months survival did not differ significantly between patients receiving PD and in-center HD. CONCLUSIONS: First-year mortality in incident dialysis patients was in addition to high age and comorbidity, associated with clinical contraindications to PD or HD, clinical symptoms, hyperphosphatemia, inflammation, and suboptimal DI. In patients with a "free" choice of dialysis modality based on their personal preferences, PD and in-center HD led to broadly similar short-term outcomes.

The Volume Difference Along the External Surface of the Zygomatic Bone: A Novel Method of Measuring Zygomatic Bone Asymmetry.

ABSTRACT: This study introduced the volume difference along the external surface (VDAES) of the zygomatic bone as a novel approach to assess zygomatic bone asymmetry and was the first to describe a distinctive, 4-step method of measuring it. VDAES has a potential to be used as an objective tool to evaluate dislocation and can assist surgeons in predicting risks of long-term cosmetic complications in patients with zygomaticomaxillary complex fractures. After having measured 100 healthy study participants, the observed median VDAES was 1.48 cm3 for all study participants, 2.02 cm3 for males, and 1.09 cm3 for females, with the gender difference being significant (P = 0.003). Additional studies are needed to test the hypothesis of whether VDAES is more relevant than conventional methods of clinically evaluating zygomatic bone asymmetry.

Sparing effect of peritoneal dialysis vs hemodialysis on BMD changes and its impact on mortality.

INTRODUCTION: Bone loss in end stage renal disease (ESRD) patients associates with fractures, vascular calcification, cardiovascular disease (CVD) and increased mortality. We investigated factors associated with changes of bone mineral density (ΔBMD) during the initial year on dialysis therapy and associations of ΔBMD with subsequent mortality in ESRD patients initiating dialysis. MATERIALS AND METHODS: In 242 ESRD patients (median age 55 years, 61% men) starting dialysis with peritoneal dialysis (PD; n = 138) or hemodialysis (HD; n = 104), whole-body dual-energy X-ray absorptiometry (DXA), body composition, nutritional status and circulating biomarkers were assessed at baseline and 1 year after dialysis start. We used multivariate linear regression analysis to determine factors associated with ΔBMD, and fine and gray competing risk analysis to determine associations of ΔBMD with subsequent mortality risk. RESULTS: BMD decreased significantly in HD patients (significant reductions of BMDtotal and BMDleg, trunk, rib, pelvis and spine) but not in PD patients. HD compared to PD therapy associated with negative changes in BMDtotal (ß=- 0.15), BMDhead (ß=- 0.14), BMDleg (ß=- 0.18) and BMDtrunk (ß=- 0.16). Better preservation of BMD associated with significantly lower all-cause mortality for ΔBMDtotal (sub-hazard ratio, sHR, 0.91), ΔBMDhead (sHR 0.91) and ΔBMDleg (sHR 0.92), while only ΔBMDhead (sHR 0.92) had a beneficial effect on CVD-mortality. CONCLUSIONS: PD had beneficial effect compared with HD on BMD changes during first year of dialysis therapy. Better preservation of BMD, especially in bone sites rich in cortical bone, associated with lower subsequent mortality. BMD in cortical bone may have stronger association with clinical outcome than BMD in trabecular bone.

Observational study of risk factors associated with clinical outcome among elderly kidney transplant recipients in Sweden - a decade of follow-up.

Kidney transplantation (Ktx) in elderly has become increasingly accepted worldwide despite their higher burden of comorbidities. We investigated important risk factors affecting long-term patient and graft survival. We included all (n = 747) Ktx patients >60 years from 2000 to 2012 in Sweden. Patients were age-stratified, 60-64, 65-69 and >70 years. Follow-up time was up to 10 years (median 7.9 years, 75% percentile >10 years). Primary outcome was 10-year patient survival in age-stratified groups. Secondary outcomes were 5-year patient and graft survival in age-stratified groups and the impact of risk factors including Charlson comorbidity index (CCI) on patient and graft survival. Mortality was higher in patients >70 years, after 10 years (HR 1.94; 95% CI 1.24-3.04; P = 0.004). Males had a higher 10-year risk of death (HR 1.39; CI 95% 1.04-1.86; P = 0.024). Five-year patient survival did not differ between age groups. In multivariate Cox analysis (n = 500), hazard ratio for 10-year mortality was 4.6 in patients with CCI ≥7 vs. <4 (95% CI 2.42-8.62; P = 0.0001). Higher CCI identified ESKD patients with 4.6 times higher risk of death after Ktx. We suggest that this index should be used as a part of the preoperative evaluation in elderly.

Fractures and their sequelae in non-dialysis-dependent chronic kidney disease: the Stockholm CREAtinine Measurement project.

INTRODUCTION: People undergoing maintenance dialysis are at high risk for fractures, but less is known about fracture incidence and associated outcomes in earlier stages of chronic kidney disease (CKD). METHODS: We conducted an observational analysis from the Stockholm Creatinine Measurement project, a Swedish health care utilization cohort during 2006-11. We identified all adults with confirmed CKD Stages 3-5 and no documented history of fractures and extracted information on comorbid history, ongoing medication, cardiovascular events and death. We studied incidence rates of fractures (overall and by location), with the estimated glomerular filtration rate (eGFR) as time-dependent exposure. We then studied hazard ratios [HRs and 95% confidence intervals (CIs)] for the events of death and major adverse cardiac events (MACE) using Cox regression with fracture as time-varying exposure. RESULTS: We identified 68 764 individuals with confirmed CKD (mean age 79 years, 56% women). During a median follow-up of 2.7 years, 9219 fractures occurred, of which 3105 were hip fractures. A more severe CKD stage was associated with a higher risk of fractures, particularly hip fractures: compared with CKD Stage 3a, the adjusted HR was 1.10 (95% CI 1.02-1.19), 1.32 (1.17-1.49) and 2.47 (1.94-3.15) for CKD Stage 3b, 4 and 5, respectively. Spline curves suggested a linear association with fracture risk with an eGFR <30 mL/min/1.73 m2. Compared with non-fracture periods, incident fracture was associated with a 4-fold increased mortality within 90 days [HR 4.21 (95% CI 3.95-4.49)]. The risk remained elevated beyond 90 days [HR 1.47 (95% CI 1.40-1.54)] and was stronger after hip fractures. Post-fracture MACE risk was also highest in the first 90 days [HR 4.02 (95% CI 3.73-4.33)], particularly after hip fractures, and persisted beyond 90 days [HR 1.20 (95% CI 1.10-1.30)]. CONCLUSION: Our findings highlight the commonness of fractures and the increased risk for subsequent adverse outcomes in CKD patients. These results may inform clinical decisions regarding post-fracture clinical surveillance and fracture prevention strategies.

Inverse J-shaped relation between coronary arterial calcium density and mortality in advanced chronic kidney disease.

BACKGROUND: The coronary artery calcium (CAC) score from cardiac computed tomography (CT) is a composite of CAC volume and CAC density. In the general population, CAC volume is positively and CAC density inversely associated with cardiovascular disease (CVD) events, implying that decreased CAC density reflects atherosclerotic plaque instability. We analysed associations of CAC indices with mortality risk in patients with end-stage renal disease [chronic kidney disease Stage 5 (CKD5)]. METHODS: In 296 CKD5 patients undergoing cardiac CT (median age 55 years, 67% male, 19% diabetes, 133 dialysed), the Framingham risk score (FRS), presence of CVD and protein-energy wasting (PEW; subjective global assessment) and high-sensitivity C-reactive protein (hsCRP) and interleukin-6 (IL-6) were determined at baseline. During follow-up for a median of 35 months, 51 patients died and 75 patients underwent renal transplantation. All-cause mortality risk was analysed with competing-risk regression models. Vascular calcification was analysed in biopsies of the arteria epigastrica inferior in 111 patients. RESULTS: Patients in the middle tertile of CAC density had the highest CAC score, CAC volume, age, CVD, PEW, FRS, hsCRP and IL-6. In competing risk analysis, the middle {subhazard ratio [sHR] 10.7 [95% confidence interval (CI) 2.0-57.3]} and high [sHR 8.9 (95% CI 1.5-51.8)] tertiles of CAC density associated with increased mortality, independent of CAC volume. The high tertile of CAC volume, independent of CAC density, associated with increased mortality [sHR 8.9 (95% CI 1.5-51.8)]. Arterial media calcification was prominent and associated with CAC volume and CAC density. CONCLUSIONS: In CKD5, mortality increased linearly with higher CAC score and CAC volume whereas for CAC density an inverse J-shaped pattern was observed, with the crude mortality rate being highest for the middle tertile of CAC density. CAC volume and CAC density were associated with the extent of arterial media calcification.

Copeptin is independently associated with vascular calcification in chronic kidney disease stage 5.

BACKGROUND: Vascular calcification (VC) is an independent predictor of cardiovascular disease (CVD) present in 30-70% of patients with chronic kidney disease (CKD). Copeptin is a sensitive surrogate marker of arginine vasopressin (AVP), which is involved in many pathophysiologic processes in CKD. The aim of the present study was to explore the association of copeptin with VC in CKD stage 5. METHODS: Copeptin was investigated in conjunction with living donor kidney transplantation in 149 clinically stable CKD stage 5 patients (CKD5), including 53 non-dialyzed (CKD5-ND) and 96 dialysis patients treated by peritoneal dialysis (PD) (n = 43) or hemodialysis (HD) (n = 53). We analyzed the association of copeptin with presence and extent of VC ascertained both histologically in biopsies from the inferior epigastric artery (n = 137) and by coronary artery calcification (CAC) score measured by computed tomography. RESULTS: Patients with higher copeptin were older, had higher systolic blood pressure, higher prevalence of CVD and their preceding time on chronic dialysis was longer. In Spearman's rank correlations (Rho), copeptin concentrations were significantly associated with CAC score (Rho = 0.27; p = 0.003) and presence of medial VC (Rho = 0.21; p = 0.016). Multivariate logistic regression analysis showed that 1-SD higher age, male gender, diabetes and 1-SD higher copeptin were significantly associated with the presence of moderate-extensive VC. CONCLUSIONS: High circulating levels of copeptin in CKD5 patients are independently associated with the degree of medial calcification ascertained by histology of arterial biopsies. Thus, plasma copeptin may serve as a marker of the uremic calcification process.

Reduced skeletal muscle expression of mitochondrial-derived peptides humanin and MOTS-C and Nrf2 in chronic kidney disease.

Advanced chronic kidney disease (CKD) is characterized by a premature aging phenotype of multifactorial origin. Mitochondrial dysfunction is prevalent in CKD and has been proposed as a major contributor to poor muscle function. Although the mitochondria-derived peptides (MDPs) humanin and mitochondrial open reading frame of 12S rRNA-c (MOTS-c) are involved in cell survival, suppression of apoptosis, and glucose control, the implications of MDP in CKD are unknown. We investigated humanin and MOTS-c protein expression in skeletal muscle and serum levels in CKD at stage 5 (glomerular filtration rate: <15 ml/min) patients and age-matched controls with normal renal function. Whereas circulating levels of humanin were increased in CKD, local muscle expression was reduced. In contrast, MOTS-c levels were reduced in both skeletal muscle and serum in CKD. Humanin in serum correlated positively to circulating TNF levels. Reduced MDP levels in skeletal muscle were associated with lower mitochondrial density and evidence of oxidative stress. These results indicate a differential regulation of MDPs in CKD and suggest an alternative site for humanin production than skeletal muscle in the uremic milieu. MDP levels were linked to systemic inflammation and evidence of oxidative stress in the muscle, two hallmark features of premature aging and uremia.

The cholinergic anti-inflammatory pathway in resistant hypertension treated with renal denervation.

BACKGROUND: Renal denervation (RDN) reduces sympathetic tone and may alter the sympathetic-parasympathetic balance. The autonomic nervous system is partly a regulator of innate immunity via the cholinergic anti-inflammatory pathway (CAP) which inhibits inflammation via the vagus nerve. Placental Growth Factor (PlGF) influences a neuro-immunological pathway in the spleen which may contribute to hypertension. The aim of this study was to investigate if modulation of renal sympathetic nerve activity affects CAP in terms of cytokine release as well as levels of PlGF. METHODS: Ten patients treated with RDN (Medtronic Inc), were analyzed for TNF, IL-1b and IL-10 and Lipopolysaccharide (LPS)-stimulated cytokine release before RDN, 1 day after and at 3- and 6-months follow-up. Four patients who underwent elective coronary angiography served as disease controls (DC). RESULTS: Baseline TNF was significantly lower 1 day after RDN (p = 0.03). LPS-stimulated (0, 10 and 100 ng/mL) TNF and IL-1b were significantly lower 1 day after RDN (TNF p = 0.0009, p = 0.0009 and p = 0.001, IL-1b; p = 0.0001, p = 0.002 and p = 0.005). IL-10 was significantly higher one day after RDN (p = ns, p = 0.02 and p = 0.01). These differences however declined during follow up. A more marked TNF reduction was achieved with a cholinergic analogue, GTS-21, in LPS-stimulated whole blood as compared with samples without GTS-21. Cytokine levels in controls did not differ before and 1 day after coronary angiography. PlGF was significantly higher in RDN patients and DC compared with healthy controls but did not change during follow-up. CONCLUSION: RDN has an immediate effect on TNF in vivo and cytokine release ex vivo but seems to wane over time suggesting that current RDN techniques may not have long-lasting immunomodulatory effect. Repeated and extended stimulation of CAP in resistant hypertension by targeting neural circuits may be a potential therapeutic strategy for treatment of both hypertension and inflammation.

Association of Serum Sclerostin with Bone Sclerostin in Chronic Kidney Disease is Lost in Glucocorticoid Treated Patients.

The osteocytic protein sclerostin inhibits bone turnover. Serum sclerostin rises early in chronic kidney disease (CKD), but if this reflects osteocyte sclerostin production is unclear, since sclerostin is also expressed in extra-skeletal tissue. Glucocorticoid treatment impacts on serum sclerostin, but the effect on the association between serum and bone sclerostin is unknown. We sought to determine whether serum sclerostin reflects bone sclerostin in different CKD stages and how this association is influenced by glucocorticoid treatment. In a cross-sectional analysis, we investigated serum sclerostin, bone sclerostin by immunohistochemistry, and bone histomorphometry in iliac crest bone biopsies from 43 patients with CKD 3-5D, including 14 dialysis patients and 22 transplanted patients (18 kidney, 4 other). Thirty-one patients were on glucocorticoid treatment at time of biopsy. Patients with low bone turnover (bone formation rate < 97 µm²/mm²/day; N = 13) had higher median serum sclerostin levels (224.7 vs. 141.7 pg/ml; P = 0.004) and higher bone sclerostin, expressed as sclerostin positive osteocytes per bone area (12.1 vs. 5.0 Scl+ osteocytes/B.Ar; P = 0.008), than patients with non-low bone turnover (N = 28). In linear regression analyses, correcting for age, gender, dialysis status and PTH, serum sclerostin was only associated with bone sclerostin in patients not treated with glucocorticoids (r2 = 0.6, P = 0.018). For the first time, we describe that female CKD patients have higher median bone sclerostin than males (11.7 vs. 5.7 Scl+ osteocytes/B.Ar, P = 0.046), despite similar serum sclerostin levels and bone histo-morphometric parameters. We conclude that glucocorticoid treatment appears to disrupt the association of serum sclerostin with bone sclerostin in CKD.

Skin autofluorescence, arterial stiffness and Framingham risk score as predictors of clinical outcome in chronic kidney disease patients: a cohort study.

BACKGROUND: The risk of cardiovascular disease (CVD) is predicted by Framingham's CVD risk scores (FRS) but the high CVD-related mortality in patients with chronic kidney disease (CKD) is only partially explained by traditional CVD risk markers. Therefore, there is a need to explore whether other CVD risk markers may improve risk prediction. Although arterial stiffness measured by augmentation index (AIx) and tissue content of advanced glycation end-products (AGEs) measured by skin autofluorescence (SAF) are two biomarkers that associate with CVD and mortality in CKD, it is not known how they compare with FRS. We evaluated associations between SAF, AIx and FRS, and their associations with CVD and mortality in CKD patients. METHODS: SAF (AGE Reader) and AIx (SphygmoCor; adjusted for 75 heart beats per minute) were measured in 261 clinically stable and extensively phenotyped patients with CKD Stage 5 (median age 56 years, 66% male, 20% diabetes; 130 non-dialysed, 93 patients on peritoneal dialysis and 38 patients on haemodialysis). Multivariate receiver operator characteristics (ROC) curve analysis and multivariate Cox models followed by C-statistics were used to evaluate CVD-related and all-cause mortality risk associated with SAF, AIx and FRS during follow-up for median 25 months with 46 deaths. RESULTS: In multivariate regression analysis, SAF associated with FRS, haemoglobin, fat body mass index and CVD, and inversely with per cent handgrip strength (HGS). AIx associated with FRS, and inversely with per cent HGS. Associations of SAF and AIx with high-sensitivity C-reactive protein (hsCRP), serum albumin, statin therapy and renal replacement therapy were not statistically significant. In ROC analysis, area under the curve (AUC) for CVD mortality ranged from AUC = 0.72 (AIx and FRS, respectively) to AUC = 0.78 (FRS + AIx), and for all-cause mortality from AUC = 0.70 (AIx) to AUC = 0.79 (FRS + AIx). In multivariate Cox analysis, after adjusting for 1-standard deviation (1-SD) of FRS, 1-SD increase of SAF associated with all-cause mortality and 1-SD increase of AIx associated with CVD mortality and all-cause mortality. After further adjustments for hsCRP, albumin and presence of CVD, AIx (but not SAF) remained independently associated with CVD mortality, hazard ratio (HR) 2.14 [95% confidence interval (95% CI) 1.18-3.89] and all-cause mortality, HR 1.74 (95% CI 1.16-2.60). CONCLUSIONS: In patients with CKD Stage 5, SAF and aortic stiffness associated with mortality, independently of FRS. After adjusting for additional confounders including inflammation, aortic stiffness remained as an independent predictor of outcome. Since the contribution of SAF and aortic stiffness compared with FRS in ROC curve analysis was relatively modest, this underlines the importance of traditional CVD risk factors in CKD.

Health-related quality of life in peritoneal dialysis patients: A narrative review.

Health-related quality of life (HRQOL) is an important aspect of patients´ health that should be an integral part of the evaluation of patient-centered outcomes, not least because HRQOL associates with patients´ morbidity and mortality. This applies also to chronic kidney disease patients, including those dependent on renal replacement therapies, the type of which may influence patients´ perception of HRQOL. Several studies have addressed HRQOL in chronic kidney disease patients undergoing renal replacement therapies, especially transplanted patients and hemodialysis patients, while publications concerning peritoneal dialysis (PD) patients are scarcer. This review describes some of the methods used to assess HRQOL, factors influencing HRQOL in PD patients, HRQOL in PD vs hemodialysis, and the relation between HRQOL and patient outcomes. We conclude that assessment of HRQOL-often neglected at present-should be included as a standard measure of patient-centered outcomes and when monitoring the quality and effectiveness of renal care including PD treatment.