Study on the mechanism of hirudin multi target delaying renal function decline in chronic kidney disease based on the "gut-kidney axis" theory

The disorder of the "gut-kidney axis" exacerbates renal function decline in chronic kidney disease (CKD), and current CKD therapy is insufficient to address this issue. Hirudin has a palliative effect on the decline of renal function. However, whether hirudin can delay CKD by regulating the "intestinal renal axis" disorder remains unclear. Unilateral ureteral ligation (UUO) induced CKD rat model, and the rats were treated with bifidobacterium and hirudin for 36 days. After 14 and 36 days of modeling, kidney and colon tissues were collected for pathology, western blot (WB) assay, and quantitative real-time PCR (qPCR) detection. Serum samples were collected for renal function testing. Fecal samples were used for 16S rRNA sequencing and research on fecal bacterial transplantation. Lipopolysaccharide combine with adenosine 5'-triphosphate (LPS + ATP)-induced intestinal epithelial cell injury was treated with a nod-like receptor pyrin domain-associated protein 3 (NLRP3) inhibitor and hirudin. Protein expression was detected using WB and qPCR. The kidneys and colons of the CKD rats exhibited varying degrees of lesions. Creatinine (CRE), blood urea nitrogen (BUN), N-acetyl-β-D-glucosidase (NAG) enzyme, and serum uremic toxins were elevated. The expression of claudin-1 and occludin was decreased, NLRP3 inflammatory-related proteins were increased, and the gut microbiota was disrupted. These pathological changes were more pronounced after 36 days of modeling. Meanwhile, high-dose hirudin treatment significantly improved these lesions and restored the intestinal flora to homeostasis in CKD rats. In vitro, hirudin demonstrated comparable effects to NLRP3 inhibitors by upregulating claudin-1 and occludin expression, and downregulating NLRP3 inflammatory-related proteins expression. The dysbiosis of the gut microbiota and impaired intestinal epithelial barrier function in CKD are associated with renal dysfunction in CKD. Hirudin delays the progression of CKD by regulating the disorder of the "gut-kidney axis" and inhibiting the activation of the NLRP3-ASC-caspase-1 pathway.

The level of serum albumin is associated with renal prognosis and renal function decline in patients with chronic kidney disease

OBJECTIVE

The study's purpose is to explore the link of serum albumin on renal progression in patients with chronic kidney disease (CKD).

METHODS

This study was a secondary analysis of a prospective cohort study in which a total of 954 participants were non-selectively and consecutively collected from the research of CKD-ROUTE in Japan between November 2010 and December 2011. We evaluated the association between baseline ALB and renal prognosis (initiation of dialysis or 50% decline in eGFR from baseline) and renal function decline (annual eGFR decline) using the Cox proportional-hazards and linear regression models, respectively. We performed a number of sensitivity analyses to ensure the validity of the results. In addition, we performed subgroup analyses.

RESULTS

The included patients had a mean age of (66.86 ± 13.41) years, and 522 (69.23%) were male. The mean baseline ALB and eGFR were (3.89 ± 0.59) g/dL and (33.43 ± 17.97) ml/min/1.73 m². The annual decline in eGFR was 2.65 mL/min/1.73 m²/year. 218 (28.9%) individuals experienced renal prognosis during a median follow-up period of 36.0 months. The baseline ALB was inversely linked with renal prognosis (HR = 0.61, 95%CI: 0.45, 0.81) and renal function decline (β = -1.41, 95%CI: -2.11, -0.72) after controlling for covariates. The renal prognosis and ALB had a non-linear connection, with ALB's inflection point occurring at 4.3 g/dL. Effect sizes (HR) were 0.42 (0.32, 0.56) and 6.11 (0.98, 38.22) on the left and right sides of the inflection point, respectively. There was also a non-linear relationship between ALB and renal function decline, and the inflection point of ALB was 4.1 g/dL. The effect sizes(β) on the left and right sides of the inflection point were -2.79(-3.62, -1.96) and 0.02 (-1.97, 1.84), respectively.

CONCLUSION

This study shows a negative and non-linear association between ALB and renal function decline as well as renal prognosis in Japanese CKD patients. When ALB is lower than 4.1 g/dL, ALB decline was closely related to poor renal prognosis and renal function decline. From a therapeutic point of view, reducing the decline in ALB makes sense for delaying CKD progression.

A disease progression model estimating the benefit of tolvaptan on time to end-stage renal disease for patients with rapidly progressing autosomal dominant polycystic kidney disease

Background

Tolvaptan was approved in the United States in 2018 for patients with autosomal dominant polycystic kidney disease (ADPKD) at risk of rapid progression as assessed in a 3-year phase 3 clinical trial (TEMPO 3:4). An extension study (TEMPO 4:4) showed continued delay in progression at 2 years, and a trial in patients with later-stage disease (REPRISE) provided confirmatory evidence of efficacy. Given the relatively shorter-term duration of the clinical trials, estimating the longer-term benefit associated with tolvaptan via extrapolation of the treatment effect is an important undertaking.

Methods

A model was developed to simulate a cohort of patients with ADPKD at risk of rapid progression and predict their long-term outcomes using an algorithm organized around the Mayo Risk Classification system, which has five subclasses (1A through 1E) based on estimated kidney growth rates. The model base-case population represents 1280 patients enrolled in TEMPO 3:4 beginning in chronic kidney disease (CKD) stages G1, G2, and G3 across Mayo subclasses 1C, 1D, and 1E. The algorithm was used to predict longer-term natural history health outcomes. The estimated treatment effect of tolvaptan from TEMPO 3:4 was applied to the natural history to predict the longer-term treatment benefit of tolvaptan. For the cohort, analyzed once reflecting natural history and once assuming treatment with tolvaptan, the model estimated lifetime progression through CKD stages, end-stage renal disease (ESRD), and death.

Results

When treated with tolvaptan, the model cohort was predicted to experience a 3.1-year delay of ESRD (95% confidence interval: 1.8 to 4.4), approximately a 23% improvement over the estimated 13.7 years for patients not receiving tolvaptan. Patients beginning tolvaptan treatment in CKD stages G1, G2, and G3 were predicted to experience estimated delays of ESRD, compared with patients not receiving tolvaptan, of 3.8 years (21% improvement), 3.0 years (24% improvement), and 2.1 years (28% improvement), respectively.

Conclusions

The model estimated that patients treated with tolvaptan versus no treatment spent more time in earlier CKD stages and had later onset of ESRD. Findings highlight the potential long-term value of early intervention with tolvaptan in patients at risk of rapid ADPKD progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02956-8.

Association of Serum Triglycerides and Renal Outcomes among 1.6 Million US Veterans

Background

Previous studies have suggested that metabolic syndrome (MetS) components are associated with renal outcomes, defined as a decline in kidney function or reaching end-stage renal disease (ESRD). Elevated triglycerides (TGs) are a component of MetS that have been reported to be associated with renal outcomes. However, the association of TGs with renal outcomes in chronic kidney disease (CKD) patients independent of the other components of the MetS remains understudied.

Methods

We examined 1,657,387 patients with data on TGs and other components of MetS in 2004–2006 and followed up until 2014. Patients with ESRD on renal replacement therapy were excluded. We examined time to ESRD, estimated glomerular filtration rate (eGFR) slope (renal function decline), and time to incident CKD (eGFR <60 mL/min/1.73 m²) among baseline normal kidney function (non-CKD) patients, using Cox or logistic regression, adjusted for clinical characteristics and MetS components. We also stratified analyses by the number of MetS components.

Results

The cohort was on average 64 years old and comprised 5% females, 15% African Americans, and 24% with nondialysis-dependent CKD. Among non-CKD patients, the adjusted relationship of TGs with time to incident CKD was strong and linear. Compared to TGs 120–<160 mg/dL, higher TGs were associated with a faster renal function decline across all CKD stages. Elevated TGs ≥240 mg/dL were associated with a faster time to ESRD among non-CKD and CKD stages 3A–3B, while the risk gradually declined to null or lower in CKD stages 4–5. Models were robust after MetS component adjustment and stratification.

Conclusion

Independent of MetS components, high TGs levels were associated with a higher incidence of CKD and a faster renal function decline, yet showed no or inverse associations with time to ESRD in CKD stages 4–5. Examining the effects of TGs-lowering interventions on incident CKD and kidney preserving therapy warrants further studies including clinical trials.

Adult-onset CblC deficiency: a challenging diagnosis involving different adult clinical specialists

Background

Methylmalonic aciduria and homocystinuria, CblC type (OMIM #277400) is the most common disorder of cobalamin intracellular metabolism, an autosomal recessive disease, whose biochemical hallmarks are hyperhomocysteinemia, methylmalonic aciduria and low plasma methionine. Despite being a well-recognized disease for pediatricians, there is scarce awareness of its adult presentation. A thorough analysis and discussion of cobalamin C defect presentation in adult patients has never been extensively performed. This article reviews the published data and adds a new case of the latest onset of symptoms ever described for the disease.

Results

We present the emblematic case of a 45-year-old male, describing the diagnostic odyssey he ventured through to get to the appropriate treatment and molecular diagnosis. Furthermore, available clinical, biochemical and molecular data from 22 reports on cases and case series were collected, resulting in 45 adult-onset CblC cases, including our own. We describe the onset of the disease in adulthood, encompassing neurological, psychiatric, renal, ophthalmic and thromboembolic symptoms. In all cases treatment with intramuscular hydroxycobalamin was effective in reversing symptoms. From a molecular point of view adult patients are usually compound heterozygous carriers of a truncating and a non-truncating variant in the MMACHC gene.

Conclusion

Adult onset CblC disease is a rare disorder whose diagnosis can be delayed due to poor awareness regarding its presenting insidious symptoms and biochemical hallmarks. To avoid misdiagnosis, we suggest that adult onset CblC deficiency is acknowledged as a separate entity from pediatric late onset cases, and that the disease is considered in the differential diagnosis in adult patients with atypical hemolytic uremic syndromes and/or slow unexplained decline in renal function and/or idiopathic neuropathies, spinal cord degenerations, ataxias and/or recurrent thrombosis and/or visual field defects, maculopathy and optic disc atrophy. Plasma homocysteine measurement should be the first line for differential diagnosis when the disease is suspected. To further aid diagnosis, it is important that genes belonging to the intracellular cobalamin pathway are included within gene panels routinely tested for atypical hemolytic uremic syndrome and chronic kidney disorders.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02179-y.

External validation of the Palacios' equation: a simple and accurate tool to estimate the new baseline renal function after renal cancer surgery

PURPOSE

To externally validate the Palacios' equation estimating the new baseline glomerular filtration rate (NB-GFR) after partial or radical-nephrectomy (PN, RN) for Renal cancer carcinoma (RCC).

MATERIALS AND METHODS

Our research group recently published two studies that investigated the association between renal function and cancer-specific survival in RCC. The first one included 3457 patients undergone RN or PN for a cT1-2 RCC coming from five high-volume centers; the second one considered 1767 patients undergone RN or PN for a cT1-4 RCC in a single high-volume center. From such datasets, available complete patients' data were used to calculate the predicted NB-GFR through the Palacios' equation: predicted NB-GFR = 35.03 + 0.65 ∙ preoperative GFR - 18.19 ∙ (if radical nephrectomy) - 0.25 ∙ age + 2.83 ∙ (if tumor size > 7 cm) - 2.09 ∙ (if diabetes). The observed NB-GFR was calculated by the CKD-EPI equation on serum creatinine at 3-12 months after surgery. Concordance between observed and predicted NB-GFR was evaluated by Lin's concordance correlation coefficient and Bland-Altman analysis.

RESULTS

2419 patients were included (1210, cohort #1; 1219, cohort #2). The median observed NB-GFR value in cohorts #1 and #2 was 73.0 ml/min/1.73 m² (IQR 56.1-90.1) and 64.2 ml/min/1.73 m² (IQR 49.6-83); the median predicted NB-GFR was 71.1 ml/min/1.73 m² (IQR 58-81.5) and 62.6 ml/min/1.73m² (IQR 47.9-75.9). The concordance line showed a slope of 0.80 and 0.86, and an intercept at 11.02 and 5.41 ml/min/1.73 m² in the cohort#1 and #2, respectively. The Palacio's equation moderately over-estimated and under-estimated NB-GFR, for values below and above the cut-off of 50 ml/min/1.73 m² and 35 ml/min/1.73m² in cohort#1 and #2. The Lin's concordance correlation coefficient was 0.79 (95% CI 0.77-0.81) and 0.83 (95% CI 0.82-0.85).

CONCLUSIONS

We confirm the predictive performances of Palacios' equation, supporting its utilization in clinical practice.

Glucose control, diabetic retinopathy, and hemodialysis induction in subjects with normo-microalbuminuric type 2 diabetic patients with normal renal function followed for 15 years

AIMS

A high urinary albumin excretion (UAE) and low glomerular filtration rate (GFR) are risk factors for progressive renal function loss in type 2 diabetic patients. In addition, diabetic retinopathy (DR) is also a risk factor for progressive renal function decline in microalbuminuric type 2 diabetic patients. We aimed to elucidate the factors, including DR, associated with a more severe situation of diabetic nephropathy, i.e., hemodialysis (HD) induction in normo- and microalbuminuric type 2 diabetic patients without renal dysfunction.

METHODS

Normo- and microalbuminuric type 2 diabetic patients with normal renal function whose GFRs had been measured by iohexol injection in 1995-1997 and had been followed for over 5 years were analyzed (n = 199). HbA1c levels was divided into HbA1c ≥ 7.0 (n = 146) and <7.0 (n = 53) groups. The UAE levels were classified as normoalbuminuria (NA, n = 114) and microalbuminuria (MA, n = 85). Seventy-two patients had DR, and 96 had hypertension. Patients were followed up for 15.7 ± 6.0 years and frequency of and duration to the HD induction were evaluated.

RESULTS

During the study period, 8 patients received HD induction. There were no remarkable differences in the rates of HD induction between patients with and without HbA1c ≥7.0, microalbuminuria, DR or hypertension. A Kaplan-Meier analysis revealed that HbA1c ≥7.0 (p = 0.037) and DR (p = 0.037) were associated with a significantly higher risk of HD induction than HbA1c <7.0 and no DR, respectively while albuminuria grade and hypertension were not associated with the risk of HD induction. There was significant negative correlation between HbA1c and annual decline rate of eGFR and annual decline rate of eGFR in the patients with prepro-proliferative DR (PDR) was significantly higher than that in the patients without DR. In the multivariate analysis, HbA1c and PDR showed significant relationships with the annual decline rate of eGFR.

CONCLUSIONS

It was reasonable that poorer glycemic control affected HD induction for 16 years follow-up. However, DR, especially PDR, should also be considered a substantial risk factor for HD induction although microalbuminuria and hypertension did not predict it at the early stage of diabetic nephropathy in type 2 diabetic patients with normal renal function.

Incidence and predictors of early and delayed renal function decline after aortic aneurysm repair in the Vascular Quality Initiative database

BACKGROUND

Postoperative acute kidney injury (AKI) may complicate both open and endovascular aortic aneurysm repair (EVAR) and is associated with substantial morbidity, mortality, and health care expense. We aim to evaluate the incidence of postoperative AKI and factors associated with its occurrence and the effects of postoperative AKI on long-term renal function and mortality after open and EVAR in the Society for Vascular Surgery Vascular Quality Initiative registry.

METHODS

Elective aneurysm cases were identified including thoracic endovascular aortic aneurysm repair (TEVAR) and complex endovascular aortic aneurysm repair (cEVAR), infrarenal endovascular repair (EVAR) and infrarenal open repair (OAR) from 2003 to 2019. The preoperative estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease formula and stratified based on chronic kidney disease (CKD) grades. Postoperative AKI was defined per the Vascular Quality Initiative definition as a creatinine increase of 0.5 mg/dL or if postoperative dialysis was required. Patients on preprocedural hemodialysis and those with previous renal transplant were excluded. Demographics and procedural factors were evaluated for predicting in-hospital postoperative AKI (all approaches) and at 9 to 21 months of long-term follow-up (EVAR only) using logistic regression modeling.

RESULTS

We identified a total of 2813 cEVAR, 2995 TEVAR, 39,945 EVAR, and 8143 OAR patients. Of those, postoperative AKI occurred in 377 cEVAR (13.5%), 199 TEVAR (6.7%), 1099 EVAR (2.8%), and 1249 OAR (15.5%). Risk factors for postoperative AKI across all groups were worse preoperative eGFR, total number of blood transfusions, perioperative anemia, reinterventions, and postoperative respiratory complications. Additional procedure-specific risk factors of postoperative AKI were preoperative hemoglobin of less than 10 and contrast volume of 125 to 150 mL, hypertension, a low ejection fraction, and a history of percutaneous revascularization for EVAR; for both EVAR/cEVAR, renal artery coverage was a risk factor, whereas for OAR, male sex, non-White race, hypertension, suprarenal aortic cross-clamp, and increased renal ischemic time were risk factors. Among 8133 EVAR patients with long-term follow-up, a decrease in kidney function occurred in 56.7% of patients with postoperative AKI vs 19.9% without postoperative AKI (P < .001). The following risk factors were associated with a decrease in renal function at long-term follow-up: postoperative AKI, a preoperative eGFR of less than 90, and hypertension. A preoperative hemoglobin of greater than 12 was protective. Postoperative AKI was associated with significantly lower survival compared with no postoperative AKI across all procedures (log rank <0.001).

CONCLUSIONS

Postoperative AKI occurs more often in patients with worse preoperative renal function, lower preoperative hemoglobin, and in open surgeries with inter-renal or suprarenal cross-clamping. Importantly, postoperative AKI is associated with increased mortality across all types of aortic repair. Given the long-term impact of postoperative AKI on outcomes for all aortic repairs and the limitations of current insensitive functional indices, there is a need to seek more sensitive indicators of decreases in early renal structural in this population.

Sex modulates the association of radial artery augmentation index with renal function decline in individuals without chronic kidney disease

PURPOSE

An increase in arterial stiffness is associated with rapid renal function decline (RFD) in patients with chronic kidney disease (CKD). The aim of this study was to investigate whether the radial augmentation index (rAI), a surrogate marker of arterial stiffness, affects RFD in individuals without CKD.

METHODS

A total of 3165 Chinese participants from an atherosclerosis cohort with estimated glomerular filtration rates (eGFR) of ≥ 60 mL/min/1.73 m² were included in this study. The baseline rAI normalized to a heart rate of 75 beats/min (rAIp75) was obtained using an arterial applanation tonometry probe. The eGFRs at both baseline and follow-up were calculated using the equation derived from the Chronic Kidney Disease Epidemiology Collaboration. The association of the rAIp75 with RFD (defined as a drop in the eGFR category accompanied by a ≥ 25% drop in eGFR from baseline or a sustained decline in eGFR of > 5 mL/min/1.73 m²/year) was evaluated using the multivariate regression model.

RESULTS

During the 2.35-year follow-up, the incidence of RFD was 7.30%. The rAIp75 had no statistically independent association with RFD after adjustment for possible confounders (adjusted odds ratio = 1.12, 95% confidence interval: 0.99-1.27, p = 0.074). When stratified according to sex, the rAIp75 was significantly associated with RFD in women, but not in men (adjusted odds ratio and 95% confidence interval: 1.23[1.06-1.43], p = 0.007 for women, 0.94[0.76-1.16], p = 0.542 for men; p for interaction = 0.038).

CONCLUSION

The rAI might help screen for those at high risk of early rapid RFD in women without CKD.

In-Hospital Blood Pressure Variability: A Novel Prognostic Marker of Renal Function Decline and Cardiovascular Events in Patients with Coronary Artery Disease

INTRODUCTION

Several measures of blood pressure (BP) variability have been associated with kidney disease and cardiovascular events. Although BP is routinely measured during hospitalization in daily practice, the prognostic impact of in-hospital BP and its variability are uncertain.

METHODS

A total of 226 participants who underwent elective percutaneous coronary intervention (PCI) for stable coronary artery disease (CAD) were included. BP was measured by trained nurses during the 4-day hospitalization for PCI. BP variability was assessed by standard deviation (SD) and coefficient variation of systolic BP. Estimated glomerular filtration rate (eGFR) was calculated at baseline and follow-up (≥6 months). The cardiovascular end point was defined as a composite of cardiovascular death, acute coronary syndrome, stroke, heart failure hospitalization, and any coronary revascularization.

RESULTS

In-hospital BP was measured 9.5 ± 0.8 times. During a median follow-up period of 1.7 years, mean eGFR change was -1.7 mL/min/1.73 m2 per year, and 35 (15.5%) participants met the cardiovascular end point. Mean systolic BP and SD were negatively correlated with eGFR change. In the receiver operating characteristic curve analysis, SD of systolic BP predicted the cardiovascular end point (AUC 0.63, best cutoff value 14.2 mm Hg, p = 0.003). Kaplan-Meier analysis demonstrated a significantly higher incidence of the cardiovascular end point in patients with SD of systolic BP ≥14.2 mm Hg compared to their counterpart (p = 0.003). A multivariable analysis showed SD of systolic BP as an independent predictor for the cardiovascular end point. When assessed with coefficient variation, BP variability was similarly related to eGFR change and clinical outcomes.

CONCLUSION

Greater in-hospital BP variability was associated with renal function decline and cardiovascular events in patients with stable CAD.

Association of hypertriglyceridemic waist phenotype with renal function impairment: a cross-sectional study in a population of Chinese adults

Background

Hypertriglyceridemic waist (HTGW) phenotype has been suggested as a risk factor for chronic kidney disease (CKD). However, there is limited evidence on the relationship of triglyceride waist phenotypes with estimated glomerular filtration rate (eGFR) status and severity. Our aim was to explore the associations of triglyceride waist phenotypes with reduced eGFR and various decreased eGFR stages among Chinese adults.

Methods

A population-based, cross-sectional study was conducted among Chinese participants aged 20–74 years from June 2016 to December 2017 in Shanghai, China. An eGFR value below 60 mL/min/1.73 m² was defined as decreased eGFR. HTGW phenotype was defined as triglyceride (TG) ≥1.7 mmol/L and a waist circumference (WC) of ≥90 cm for men and ≥ 80 cm for women. We examined the association of triglyceride waist phenotypes with decreased eGFR risk using the weighted logistic regression models.

Results

A total of 31,296 adults were included in this study. Compared with normal TG level/normal WC (NTNW) phenotype, normal TG level/enlarged WC (NTGW) and elevated TG level/enlarged WC (HTGW) phenotypes were associated with the increased risk of decreased eGFR. Multivariable-adjusted ORs (95% CI) associated with NTGW, elevated TG level/normal WC (HTNW), and HTGW phenotypes were 1.75 (1.41–2.18), 1.29 (0.99–1.68), and 1.99 (1.54–2.58), respectively. These associations between triglyceride waist phenotypes and decreased eGFR risk remained across almost all the subgroups, including sex, age, BMI, T2DM, and hypertension. HTGW phenotype was consistently positively associated with the risk of mildly and moderately decreased eGFR, but not with severely decreased eGFR risk.

Conclusions

HTGW was consistently associated with the increased risk of decreased eGFR and various decreased eGFR stages, except for severely decreased eGFR. Further prospective studies are warranted to confirm our findings and to investigate the underlying biological mechanisms.

Association of Metabolic Syndrome and Its Components with Decreased Estimated Glomerular Filtration Rate in Adults

BACKGROUND/AIMS

Metabolic syndrome (MetS) and its metabolic components, the common risk factors, may be involved in the development and progression of decreased estimated glomerular filtration rate (eGFR). The aim of this study was to examine the association of MetS and its metabolic components with eGFR status and severity among Chinese adults.

METHODS

The population-based, cross-sectional study recruited a total of 33,300 Chinese adults (aged ≥18 years) from 4 study community sites in Songjiang District, Shanghai, between June 2016 and December 2017. Decreased eGFR was defined as a value of eGFR below 60 mL/min/1.73 m2. Weighted multiple logistic regression models were used to examine the association of MetS and its components with eGFR status and severity.

RESULTS

After adjusting for potential confounders, subjects with MetS had an increased risk of decreased eGFR with an adjusted OR of 1.76 (95% CI 1.53-2.01), and subjects with increasing numbers of MetS components had a gradually increased risk for decreased eGFR (p trend <0.001). The multivariable-adjusted ORs (95% CI) of decreased eGFR were 1.66 (1.44-1.93) for abdominal obesity, 1.37 (1.18-1.60) for elevated triglycerides, 1.13 (0.96-1.33) for reduced high-density lipoprotein cholesterol, 0.84 (0.72-0.98) for elevated fasting glucose, and 1.92 (1.57-2.35) for elevated blood pressure (BP). Furthermore, these associations remained in most of the subgroups analyses. Significant associations between elevated BP and the risks of mildly, moderately, and severely decreased eGFR were also found.

CONCLUSIONS

MetS was independently associated with an increased risk of decreased eGFR, and individual components of MetS each play a different role in decreased eGFR. Elevated BP may be an important risk factor for the progression of renal dysfunction or even chronic kidney disease.

Predictive performance of lipid accumulation product and visceral adiposity index for renal function decline in non-diabetic adults, an 8.6-year follow-up

BACKGROUND

Lipid accumulation product (LAP) and visceral adiposity index (VAI) are surrogates for visceral adiposity dysfunction. Our aim was to evaluate potential association of these two indices with the incidence of renal function decline.

METHODS

We included 6693 non-diabetic adults age ≥ 18 years, with estimated glomerular filtration rate (eGFR) ≥ 60 ml/min/1.73 m², from the Tehran Lipid and Glucose Study 2002-2005 survey. Natural logarithmic transformation (Ln) was applied for LAP and VAI measures. The incidence of renal function decline, defined as eGFR < 60 ml/min/1.73 m², was evaluated for each gender, across tertiles of Ln LAP, Ln VAI, body mass index (BMI), waist circumference (WC), waist to height ratio (WHtR) and waist to hip ratio (WHR), using Cox-proportional hazard models.

RESULTS

Over a median 8.6 years of follow-up, 1670 new cases of renal function decline were identified (incidence rate 3.2%). After multivariable adjustment, the hazard ratios (HRs) with 95% CI across second and third tertiles of Ln LAP were 1.14 (0.86-1.50) and 1.33 (1.00-1.78) in men (P trend = 0.132); and 1.16 (0.90-1.50) and 1.24 (0.96-1.61) in women (P trend = 0.263), respectively. Multivariable adjusted HRs across second and third tertiles of Ln VAI were 1.40 (1.08-1.83) and 1.35 (1.02-1.78) in men (P trend = 0.031); and 0.93 (0.75-1.15) and 1.15 (0.93-1.41) in women (P trend = 0.072), respectively. HRs across tertiles of BMI, WC, WHtR and WHR were not significant for renal function decline among both genders in any adjustment models.

CONCLUSION

Among the adiposity indices assessed in this study, VAI seems to be an independent predictor of renal function decline only in males.

Long-Term Effects of Intensive Low-Salt Diet Education on Deterioration of Glomerular Filtration Rate among Non-Diabetic Hypertensive Patients with Chronic Kidney Disease

BACKGROUND

Diet modification, especially a decrease in salt intake, might be an important non-pharmacological strategy to improve chronic kidney disease (CKD) prognosis.

OBJECTIVES

We conducted a prospective cohort study to investigate whether an intensive low-salt diet education program effectively attenuated the rate of renal function decline in hypertensive patients with CKD.

METHODS

This cohort study recruited 171 participants from a previous open-labelled, case-controlled, randomized clinical trial that originally consisted of 245 hypertensive CKD patients who were assigned to two groups, intensive low-salt diet or conventional education. We evaluated the renal outcomes, which included the rate of change in estimated glomerular filtration rate (eGFR) per year, the increase in serum creatinine ≥50%, the decrease in eGFR ≥30%, and the percent change in albuminuria throughout the entire study period.

RESULTS

The baseline characteristics of the cohort participants between the two groups were similar at the time of trial phase randomization. During the whole study period, the rate of renal function decline was significantly faster in the conventional group (0.11 ± 4.63 vs. -1.53 ± 3.04 mL/min/1.73 m2/year, p = 0.01). The percent of incremental change in serum creatinine ≥50% was 1.1% in the intensive group and 8.2% in the conventional group (p = 0.025), and the percent of decremental change in eGFR ≥30% was 3.3% in the intensive group and 11.1% in the conventional group (p= 0.048). With logistic regression analysis adjusted for related factors, we found that the conventional group showed a higher risk for deterioration in serum creatinine and eGFR during the entire study period. Especially, we found that the intensive education program preserved eGFR in participants with one, several, or all of the following characteristics at the time of randomization: older age, female, obese, had higher protein intake, higher amounts of albuminuria, higher salt intake.

CONCLUSION

This cohort study demonstrated that an intensive low-salt diet education program attenuated the rate of renal function decline in hypertensive CKD patients independent of its effect on lowering salt intake or albuminuria during the 36 months of follow-up.

Modelling the long-term benefits of tolvaptan therapy on renal function decline in autosomal dominant polycystic kidney disease: an exploratory analysis using the ADPKD outcomes model

Background

The short-term efficacy of tolvaptan in patients with autosomal dominant polycystic kidney disease (ADPKD) has been demonstrated across several phase 3 trials, while the ADPKD Outcomes Model (ADPKD-OM) represents a validated approach to predict natural disease progression over a lifetime horizon. This study describes the implementation of a tolvaptan treatment effect within the ADPKD-OM and explores the potential long-term benefits of tolvaptan therapy in ADPKD.

Methods

The effect of tolvaptan on ADPKD progression was modelled by applying a constant treatment effect to the rate of renal function decline, consistent with that observed in the Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and Its Outcomes trial (TEMPO 3:4; ClinicalTrials.gov identifier NCT00428948). Predictions generated by the ADPKD-OM were compared against aggregated data from a subsequent extension trial (TEMPO 4:4; ClinicalTrials.gov identifier NCT01214421) and the Replicating Evidence of Preserved Renal Function an Investigation of Tolvaptan Safety Efficacy in ADPKD trial (REPRISE; ClinicalTrials.gov identifier NCT02160145). Following validation, an application of the ADPKD-OM sought to estimate the benefit of tolvaptan therapy on time to end-stage renal disease (ESRD), in a range of ADPKD populations.

Results

Model validation against TEMPO 4:4 and REPRISE demonstrated the accuracy and generalisability of the tolvaptan treatment effect applied within the ADPKD-OM. In simulated patients matched to the overall TEMPO 3:4 trial population at baseline, tolvaptan therapy was predicted to delay the mean age of ESRD onset by five years, compared to natural disease progression (57 years versus 52 years, respectively). In subgroup and sensitivity analyses, the estimated delay to ESRD was greatest among patients with CKD stage 1 at baseline (6.6 years), compared to CKD 2 and 3 subgroups (4.7 and 2.7 years, respectively); and ADPKD patients in Mayo subclasses 1C–1E.

Conclusions

This study demonstrated the potential for tolvaptan therapy to delay time to ESRD, particularly among patients with early-stage CKD and evidence of rapidly progressing disease. Data arising from this study highlight the value to be gained by early intervention and long-term treatment with tolvaptan, which may alleviate the economic and societal costs of providing care to patients who progress to ESRD.

Compound α-keto acid tablet supplementation alleviates chronic kidney disease progression via inhibition of the NF-kB and MAPK pathways

Background

Keto-analogues administration plays an important role in clinical chronic kidney disease (CKD) adjunctive therapy, however previous studies on their reno-protective effect mainly focused on kidney pathological changes induced by nephrectomy. This study was designed to explore the currently understudied alternative mechanisms by which compound α-ketoacid tablets (KA) influenced ischemia–reperfusion (IR) induced murine renal injury, and to probe the current status of KA administration on staving CKD progression in Chinese CKD patients at different stages.

Methods

In animal experiment, IR surgery was performed to mimic progressive chronic kidney injury, while KA was administrated orally. For clinical research, a retrospective cohort study was conducted to delineate the usage and effects of KA on attenuating CKD exacerbation. End-point CKD event was defined as 50% reduction of initial estimated glomerular filtration rate (eGFR). Kaplan–Meier analysis and COX proportional hazard regression model were adopted to calculate the cumulative probability to reach the end-point and hazard ratio of renal function deterioration.

Results

In animal study, KA presented a protective effect on IR induced renal injury and fibrosis by attenuating inflammatory infiltration and apoptosis via inhibition of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. In clinical research, after adjusting basic demographic factors, patients at stages 4 and 5 in KA group presented a much delayed and slower incidence of eGFR decrease compared to those in No-KA group (hazard ratio (HR) = 0.115, 95% confidence interval (CI) 0.021–0.639, p = 0.0134), demonstrating a positive effect of KA on staving CKD progression.

Conclusion

KA improved IR induced chronic renal injury and fibrosis, and seemed to be a prospective protective factor in end stage renal disease.

A model to predict disease progression in patients with autosomal dominant polycystic kidney disease (ADPKD): the ADPKD Outcomes Model

Background

Autosomal dominant polycystic kidney disease (ADPKD) is the leading inheritable cause of end-stage renal disease (ESRD); however, the natural course of disease progression is heterogeneous between patients. This study aimed to develop a natural history model of ADPKD that predicted progression rates and long-term outcomes in patients with differing baseline characteristics.

Methods

The ADPKD Outcomes Model (ADPKD-OM) was developed using available patient-level data from the placebo arm of the Tolvaptan Efficacy and Safety in Management of ADPKD and its Outcomes Study (TEMPO 3:4; ClinicalTrials.gov identifier NCT00428948). Multivariable regression equations estimating annual rates of ADPKD progression, in terms of total kidney volume (TKV) and estimated glomerular filtration rate, formed the basis of the lifetime patient-level simulation model. Outputs of the ADPKD-OM were compared against external data sources to validate model accuracy and generalisability to other ADPKD patient populations, then used to predict long-term outcomes in a cohort matched to the overall TEMPO 3:4 study population.

Results

A cohort with baseline patient characteristics consistent with TEMPO 3:4 was predicted to reach ESRD at a mean age of 52 years. Most patients (85%) were predicted to reach ESRD by the age of 65 years, with many progressing to ESRD earlier in life (18, 36 and 56% by the age of 45, 50 and 55 years, respectively). Consistent with previous research and clinical opinion, analyses supported the selection of baseline TKV as a prognostic factor for ADPKD progression, and demonstrated its value as a strong predictor of future ESRD risk. Validation exercises and illustrative analyses confirmed the ability of the ADPKD-OM to accurately predict disease progression towards ESRD across a range of clinically-relevant patient profiles.

Conclusions

The ADPKD-OM represents a robust tool to predict natural disease progression and long-term outcomes in ADPKD patients, based on readily available and/or measurable clinical characteristics. In conjunction with clinical judgement, it has the potential to support decision-making in research and clinical practice.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0804-2) contains supplementary material, which is available to authorized users.

Long-term effect of coffee consumption on autosomal dominant polycystic kidneys disease progression: results from the Suisse ADPKD, a Prospective Longitudinal Cohort Study

Background

Previous in vitro experiments of human polycystic kidney disease (PKD) cells reported that caffeine is a risk factor for the promotion of cyst enlargement in patients with autosomal dominant PKD (ADPKD). The relentless progression of ADPKD inclines the majority of physicians to advocate minimization of caffeine consumption despite the absence of clinical data supporting such a recommendation so far. This is the first clinical study to assess prospectively the association between coffee consumption and disease progression in a longitudinal ADPKD cohort.

Methods

Information on coffee consumption and disease progression was collected at each follow-up visit using standardized measurement methods. The main model for the outcomes, kidney size (height-adjusted total kidney volume, htTKV) and kidney function (estimated glomerular filtration rate, eGFR), was a linear mixed model. Patients entered the on-going Swiss ADPKD study between 2006 and June 2014 and had at least 1 visit every year. The sample size of the study population was 151 with a median follow-up of 4 visits per patient and a median follow-up time of 4.38 years.

Results

After multivariate adjustment for age, smoking, hypertension, sex, body mass index and an interaction term (coffee*visit), coffee drinkers did not have a statistically significantly different kidney size compared to non-coffee drinkers (difference of −33.03 cm³ height adjusted TKV, 95% confidence interval (CI) from −72.41 to 6.34, p = 0.10). After the same adjustment, there was no statistically significant difference in eGFR between coffee and non-coffee drinkers (2.03 ml/min/1.73 m², 95% CI from −0.31 to 4.31, p = 0.089).

Conclusion

Data derived from our prospective longitudinal study do not confirm that drinking coffee is a risk factor for ADPKD progression.

Electronic supplementary material

The online version of this article (doi:10.1007/s40620-017-0396-8) contains supplementary material, which is available to authorized users.

Patients with type 2 diabetes having higher glomerular filtration rate showed rapid renal function decline followed by impaired glomerular filtration rate: Japan Diabetes Complications Study

AIMS

The Japan Diabetes Complications Study (JDCS), a nation-wide, multicenter, prospective study of patients with type 2 diabetes, reported that hemoglobin A_1c (HbA_1c), systolic blood pressure, and smoking were risk factors for the onset of macroalbuminuria. This study explored the risk factors for glomerular filtration rate (GFR) decline in the JDCS patients.

METHODS

We examined the 1407 JDCS patients (667 women, mean age 59years, 974 normoalbuminuria, 433 microalbuminuria) whose urinary albumin-to-creatinine ratio (UACR) and estimated GFR (eGFR) were determined at baseline with an 8-year follow-up. We divided all the patients into four groups according to baseline eGFR: G1 (120≤eGFR), G2 (90≤eGFR<120), G3 (60≤eGFR<90), G4 (eGFR<60).

RESULTS

The eGFRs in groups G1 and G2 decreased at follow-up compared to those at the baseline. The risk of annual eGFR decline rate≥3ml/min/1.73m² (rapid decliners) increased as the baseline eGFR increased. Advanced age, high HbA_1c, and UACR, or diabetic retinopathy at baseline were risk factors for the rapid decliners. Especially the G1 group had a significant risk for the rapid decliners. The frequency of the patients with GFR<60ml/min/1.73m² at the follow-up amounted to 31.1% in the rapid decliners, which was higher than 12% in the non-rapid decliners.

CONCLUSIONS

In normo- and microalbuminuric patients with type 2 diabetes, extra careful attention should be paid to patients with eGFR ≥120ml/min/1.73m² to detect cases with rapidly decreased GFR under the normal range.

The PR interval and QRS duration could be predictors of renal function decline

OBJECTIVE

Previous studies have implicated PR interval (iPR) and QRS duration (dQRS) obtained by electrocardiography in independent predictors of cardiovascular disease, which often precedes renal dysfunction. The aim of this study was to examine whether iPR or dQRS could be a predictor of renal function decline in a community-based cohort.

METHODS

We enrolled 1149 healthy subjects, and retrospectively evaluated the relationships between iPR or dQRS and renal function decline, observation period of which was 3 years, and assessed whether iPR or dQRS could predict renal function decline.

RESULTS

The iPR (r=-0.102, p=0.0006) or dQRS (r=-0.097, p=0.0010) was negatively associated with a rate of decline in estimated glomerular filtration rate (eGFR). Multiple regression analyses revealed that iPR (β=-0.095, p=0.0023) or dQRS (β=-0.069, p=0.0351) was an independent determinant of the rate of decline in eGFR after adjustment for covariates. Logistic regression analyses demonstrated that the longest iPR (odds ratios (OR), 2.03; 95% confidence intervals (CI), 1.49 to 2.76; p<0.0001) or dQRS (OR, 1.62; 95% CI, 1.16 to 2.25; p=0.0043) tertile showed an increased OR for prevalence of the rate of decline in eGFR≤1 ml/min/1.73 m2/year compared to the shortest iPR or dQRS tertile after adjustment for covariates.

CONCLUSION

The iPR and dQRS could be independent predictors of renal function decline in healthy subjects.

Nephrotic range proteinuria as a strong risk factor for rapid renal function decline during pre-dialysis phase in type 2 diabetic patients with severely impaired renal function

BACKGROUND

Proteinuria is an established risk factor for progression of renal disease, including diabetic nephropathy. The predictive power of proteinuria, especially nephrotic range proteinuria, for progressive renal deterioration has been well demonstrated in diabetic patients with normal to relatively preserved renal function. However, little is known about the relationship between severity of proteinuria and renal outcome in pre-dialysis diabetic patients with severely impaired renal function.

METHODS

125 incident dialysis patients with type 2 diabetes were identified. This study was aimed at retrospectively evaluating the impact of nephrotic range proteinuria (urinary protein-creatinine ratio above 3.5 g/gCr) on renal function decline during the 3 months just prior to dialysis initiation.

RESULTS

In total, 103 patients (82.4 %) had nephrotic range proteinuria. The median rate of decline in estimated glomerular filtration rate (eGFR) in this study population was 0.98 (interquartile range 0.51-1.46) ml/min/1.73 m(2) per month. Compared to patients without nephrotic range proteinuria, patients with nephrotic range proteinuria showed significantly faster renal function decline (0.46 [0.24-1.25] versus 1.07 [0.64-1.54] ml/min/1.73 m(2) per month; p = 0.007). After adjusting for gender, age, systolic blood pressure, serum albumin, calcium-phosphorus product, hemoglobin A1c, and use of an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker, patients with nephrotic range proteinuria showed a 3.89-fold (95 % CI 1.08-14.5) increased risk for rapid renal function decline defined as a decline in eGFR ≥0.5 ml/min/1.73 m(2) per month.

CONCLUSION

Nephrotic range proteinuria is the predominant renal risk factor in type 2 diabetic patients with severely impaired renal function receiving pre-dialysis care.

Lipid levels and renal function decline in pre-dialysis patients

Background

Little is known about the effect of low-density lipoprotein (LDL) cholesterol, triglyceride (TG), and high-density lipoprotein (HDL) cholesterol levels on renal function decline in patients receiving specialized pre-dialysis care.

Methods

In the prospective PREPARE-2 study, incident patients starting pre-dialysis care were included when referred to one of the 25 participating Dutch specialized pre-dialysis outpatient clinics (2004-2011). Clinical and laboratory data were collected every 6 months. A linear mixed model was used to compare renal function decline between patients with LDL cholesterol, TG, or HDL cholesterol levels above and below the target goals (LDL cholesterol: <2.50 mmol/l, TG: <2.25 mmol/l, and HDL cholesterol: ≥1.00 mmol/l). Additionally the HDL/LDL cholesterol ratio was investigated (≥0.4).

Results

In our study population (n = 306), the median age was 69 years and 70% were male. Patients with LDL cholesterol levels above the target of 2.50 mmol/l experienced an accelerated renal function decline compared to patients with levels below the target (crude additional decline: 0.10 ml/min/1.73 m²/month, 95% CI 0.00-0.20; p < 0.05). A similar trend was found for TG levels above the target of 2.25 mmol/l (0.05 ml/min/1.73 m²/month, 95% CI −0.06 to 0.16) and for a HDL/LDL cholesterol ratio below 0.4 (0.06 ml/min/1.73 m²/month, 95% CI −0.05 to 0.18). Adjustment for potential confounders resulted in similar results, and the exclusion of patients who were prescribed lipid-lowering medication (statin, fibrate, or cholesterol absorption inhibitor) resulted in a slightly larger estimated effect.

Conclusion

High levels of LDL cholesterol were associated with an accelerated renal function decline, independent of the prescription of lipid-lowering medication.

Metabolic syndrome, but not insulin resistance, is associated with an increased risk of renal function decline

BACKGROUND & AIMS

The purpose of this study was to evaluate the effect of metabolic syndrome (Mets) and insulin resistance (IR) on the risk of renal function decline (RFD) in a rural Chinese cohort.

METHODS

A total of 2696 subjects aged 40-71 years with normal renal function were followed-up for 7 years. RFD was defined using the Kidney Disease: Improving Global Outcome definition, i.e., a drop in estimated glomerular filtration rate (eGFR) category accompanied by a 25% or greater drop in eGFR from baseline or a sustained decline in eGFR of more than 5 mL/min/1.73 m(2)/year.

RESULTS

During the 7-year follow-up, 9.0% of the subjects developed RFD. Subjects with Mets at baseline had an increased risk of RFD with an adjusted odds ratio (OR) of 1.77 (95%CI: 1.25-2.52), and there was a graded relationship between the numbers of Mets components and the risk for RFD. Exclusion of the subjects with hypertension (1.65; 0.99-2.75) or diabetes (1.86; 1.30-2.67) at baseline or further adjustment for IR (1.72; 1.15-2.57) did not substantially change the association between Mets and the risk of RFD. Moreover, the ORs of Mets status for RFD in the older group (≥55 years) were 2.14 (1.06-4.33) times of that in the younger group (<55 years) and 2.26 (1.07-4.78) times in hypercholesterolemia group (≥5.2 mmol/L) of that in the normal (<5.2 mmol/L) group. The baseline IR was not associated with the risk for RFD.

CONCLUSIONS

Mets, but not IR, was associated with an increased risk for RFD. And there was a detrimental interaction of Mets with older age and hypercholesterolemia on the risk of RFD.

A longitudinal assessment of the natural rate of decline in renal function with age

BACKGROUND

Cross-sectional studies have long suggested that renal function declines with age. Longitudinal studies regarding this issue are limited.

METHODS

We retrospectively analyzed a database of subjects attending a screening center in Israel between the years 2000-2012. Only subjects with normal estimated glomerular filtration rate (eGFR) were included. eGFR was assessed consequently at 5 or more yearly visits. The rate of decline in GFR with age was assessed in healthy subjects and in subjects with comorbidities.

RESULTS

The cohort included 2693 healthy subjects and 230 subjects with different comorbidities. Mean (±standard error) annual rate of decline in eGFR in healthy subjects was 0.97 ± 0.02 ml/min/year/1.73 m(2). This decline increased significantly from 0.82 ± 0.22 in age-group 20-30 years to 0.84 ± 0.08, 1.07 ± 0.08 and 1.15 ± 0.12 ml/min/year/1.73 m(2) in age groups 31-40, 41-50 and 50 years and older respectively (p < 0.001). No correlation was found between the annual decline in eGFR and body mass index. In subjects with hypertension, diabetes mellitus, impaired fasting glucose or combined comorbidity the decline in eGFR was 1.12 ± 0.12, 0.77 ± 0.16, 0.85 ± 0.17, and 1.18 ± 0.26 ml/min/year/1.73 m(2) respectively.

CONCLUSIONS

This large longitudinal study provides new data on the decrease in eGFR with age. Accurate prediction of the natural rate of GFR decline might be used to distinguish between normally aging kidneys and those with chronic disease. This approach could avoid unnecessary diagnostic procedures in the former and facilitate appropriate treatment in the latter.

The aging kidney revisited: a systematic review

As for the whole human body, the kidney undergoes age-related changes which translate in an inexorable and progressive decline in renal function. Renal aging is a multifactorial process where gender, race and genetic background and several key-mediators such as chronic inflammation, oxidative stress, the renin-angiotensin-aldosterone (RAAS) system, impairment in kidney repair capacities and background cardiovascular disease play a significant role. Features of the aging kidney include macroscopic and microscopic changes and important functional adaptations, none of which is pathognomonic of aging. The assessment of renal function in the framework of aging is problematic and the question whether renal aging should be considered as a physiological or pathological process remains a much debated issue. Although promising dietary and pharmacological approaches have been tested to retard aging processes or renal function decline in the elderly, proper lifestyle modifications, as those applicable to the general population, currently represent the most plausible approach to maintain kidney health.

Calorimetric analysis of the plasma proteome: identification of type 1 diabetes patients with early renal function decline

BACKGROUND

Microalbuminuria (MA) has been questioned as a predictor of progressive renal dysfunction in patients with type 1 diabetes (T1D). Consequently, new clinical end points are needed that identify or predict patients that are at risk for early renal function decline (ERFD). The potential clinical utility of differential scanning calorimetry (DSC) analysis of blood plasma and other biofluids has recently been reported. This method provides an alternate physical basis with which to study disease-associated changes in the bulk plasma proteome.

METHODS

DSC analysis of blood plasma was applied to identify unique signatures of ERFD in subjects enrolled in the 1st Joslin Study of the Natural History of Microalbuminuria in Type 1 Diabetes, a prospective cohort study of T1D patients. Recent data suggests that differences in the plasma peptidome of these patients correlate with longitudinal measures of renal function. Differences in DSC profile (thermogram) features were evaluated between T1D MA individuals exhibiting ERFD (n=15) and matched control subjects (n=14).

RESULTS

The average control group thermogram resembled a previously defined healthy thermogram. Differences were evident between ERFD and control individuals. Heat capacity values of the main two transitions were found to be significant discriminators of patient status.

CONCLUSIONS

Results from this pilot study suggest the potential utility of DSC proteome analysis to prognostic indicators of renal disease in T1D.

GENERAL SIGNIFICANCE

DSC shows sensitivity to changes in the bulk plasma proteome that correlate with clinical status in T1D providing additional support for the utility of DSC profiling in clinical diagnostics.