Risk factors for chronic kidney disease: an update

Kidney aging process and the management of the elderly patient with renal impairment (Review)

As life expectancy increases, a rise in the number of chronically ill patients is observed due to the aging population. Among the various diseases, chronic kidney disease is at present one of the main causes of morbidity and, due to its typical complications, it is also one of the most important causes of mortality in the general population. For these reasons, the understanding of the kidney aging process, its consequences and its adequate management are essential. The judicious use of certain types of drugs, the prevention of episodes of renal injury either by toxic mechanisms or by dehydration are important aspects and are part of the apropriate approach for elderly patients. The most effective treatment of various types of conditions with a negative impact on renal function and for which an increased incidence is known as we age should also be considered. Thus, in the case of elderly patients, in order to protect the kidneys, an integrative approach is recommended, one that includes both elements of prevention and the appropriate treatment of existing diseases.

Rice bran modulates renal disease risk factors in animals submitted to high sugar-fat diet

Introduction:

Obesity, diabetes, and hypertension are common risk factors for chronic kidney disease (CKD). CKD arises due to many pathological insults, including inflammation and oxidative stress, which affect renal function and destroy nephrons. Rice bran (RB) is rich in vitamins and minerals, and contains significant amount of antioxidants. The aim of this study was to evaluate the preventive effect of RB on renal disease risk factors.

Methods:

Male Wistar rats (±325 g) were divided into two experimental groups to received a high sugar-fat diet (HSF, n = 8) or high sugar-fat diet with rice bran (HSF + RB, n = 8) for 20 weeks. At the end, renal function, body composition, metabolic parameters, renal inflammatory and oxidative stress markers were analyzed.

Results:

RB prevented obesity [AI (HSF= 9.92 ± 1.19 vs HSF + RB= 6.62 ± 0.78)], insulin resistance [HOMA (HSF= 83 ± 8 vs. HSF + RB= 42 ± 11)], dyslipidemia [TG (HSF= 167 ± 41 vs. HSF + RB=92 ± 40)], inflammation [TNF-α (HSF= 80 ± 12 vs. HSF + RB=57 ± 14), IL-6 (903 ± 274 vs. HSF + RB=535 ± 277)], oxidative stress [protein carbonylation (HSF= 3.38 ± 0.18 vs. HSF + RB=2.68 ± 0.29), RAGE (HSF=702 ± 36 vs. RSF + RB=570 ± 190)], and renal disease [protein/creatinine ratio (HSF=1.10 ± 0.38 vs. HSF + RB=0.49 ± 0.16)].

Conclusion:

In conclusion, rice bran prevented renal disease by modulating risk factors.

Target delivery of drug carriers in mice kidney glomeruli via renal artery. Balance between efficiency and safety

Targeting drug delivery systems is crucial to reducing the side effects of therapy. However, many of them are lacking effectiveness for kidney targeting, due to systemic dispersion and accumulation in the lungs and liver after intravenous administration. Renal artery administration of carriers provides their effective local accumulation but may cause irreversible vessel blockage. Therefore, the combination of the correct administration procedure, suitable drug delivery system, selection of effective and safe dosage is the key to sparing local therapy. Here, we propose the 3-μm sized fluorescent capsules based on poly-L-arginine and dextran sulfate for targeting the kidney via a mice renal artery. Hemodynamic study of the target kidney in combination with the histological analysis reveals a safe dose of microcapsules (20 × 10⁶), which has not lead to irreversible pathological changes in blood flow and kidney tissue, and provides retention of 20.5 ± 3% of the introduced capsules in the renal cortex glomeruli. Efficacy of fluorescent dye localization in the target kidney after intra-arterial administration is 9 times higher than in the opposite kidney and after intravenous injection. After 24 h microcapsules are not observed in the target kidney when the safe dose of carriers is being used but a high level of fluorescent signal persists for 48 h indicating that fluorescent cargo accumulation in tissues. Injection of non-safe microcapsule dose leads to carriers staying in glomeruli for at least 48 h which has consequences of blood flow not being restored and tissue damage being observed in histology.

Burden of Chronic Kidney Disease by KDIGO Categories of Glomerular Filtration Rate and Albuminuria: A Systematic Review

Introduction

The Kidney Disease: Improving Global Outcomes (KDIGO) 2012 guidelines recommend classifying patients by glomerular filtration rate (GFR) and albuminuria to predict chronic kidney disease (CKD) prognosis. The aim of this systematic review was to explore the epidemiological burden of CKD stratified by the KDIGO 2012 categories.

Methods

MEDLINE® and Embase were searched for observational studies of patients with CKD with results stratified according to the KDIGO 2012 classification. Investigated outcomes were prevalence, incidence, and risk factors and complications of CKD, including mortality.

Results

The review included ten observational studies with 3033 to 46,949 participants, conducted in the USA, China, France, Italy and Spain. The most frequently reported outcome was the prevalence of CKD (GFR categories G3–5), ranging from 2% to 17%. Most participants were normoalbuminuric, with 0.4–3.2% macroalbuminuric, and most fell within the KDIGO 2012 low-risk or moderate-risk groups, with 0.9–5.6% in the high-risk and 0.3–4.8% in the very high-risk groups. Although scarce, data on the prevalence of comorbidities in CKD according to the KDIGO classification suggest that they increase with albuminuria severity.

Conclusions

Patients with CKD frequently have complications, but only a small proportion have severely increased albuminuria or fall within the KDIGO high-risk or very high-risk groups. These groups, however, are associated with the highest burden of disease, as comorbidities are more prevalent with increasing albuminuria severity. New studies framed by the KDIGO 2012 classification are needed to address key gaps in the understanding of CKD burden and outcomes.

Electronic supplementary material

The online version of this article (10.1007/s12325-020-01568-8) contains supplementary material, which is available to authorized users.

Markers of Kidney Function and Longitudinal Cognitive Ability Among Older Community-Dwelling Adults: The Rancho Bernardo Study

BACKGROUND

Reduced kidney function has been associated with cognitive decline. Most studies have examined a single marker of kidney function and have limited duration of follow-up.

OBJECTIVE

This study evaluated associations between markers of kidney function (urine albumin, estimated glomerular filtration rate [eGFR], and hyperuricemia) with cognitive performance over time.

METHODS

This is a longitudinal study of 1,634 community-dwelling adults (mean age = 71.7 years), with kidney function markers and cognitive ability measured at baseline (1992-1996) and at up to five additional time points with a maximum of 23.4 years (mean = 8.1 years) of follow-up. Associations between kidney function and cognitive performance were assessed using linear mixed effects models. Testing for interaction by sex was conducted.

RESULTS

Albuminuria (urine albumin-to-creatinine ratio [ACR]≥30 mg/g) was associated with steeper annual declines in global cognitive function (MMSE, β= -0.12, p = 0.003), executive function (Trails B, β= 4.50, p < 0.0001) and episodic memory (Buschke total recall, β= -0.62, p = 0.02) scores in men. Results were similar when cognitive test scores were regressed on latent trajectory classes of ACR. In men, hyperuricemia (serum uric acid [SUA]≥6.8 mg/dl for men and SUA≥6.0 mg/dl for women) was associated with lower baseline MMSE (β= -0.70, p = 0.009) scores but not with MMSE change over time. No such associations were detected in women. There were no significant associations between eGFR and cognitive performance for either sex.

CONCLUSION

In older men, albuminuria is an independent predictor of subsequent cognitive decline. More investigations are needed to explain the observed sex differences and the potential relationship between hyperuricemia and poorer global cognition.

Prevalence of Chronic Kidney Diseases in Patients with Diabetes Mellitus in the Middle East: A Systematic Review and Meta-Analysis

AIMS

The prevalence of CKD in patients with diabetes mellitus in the Middle East region is unknown. Therefore, we aimed to understand the pooled prevalence of CKD in patients with diabetes mellitus in the Middle East region.

METHODS

PubMed, Embase, and Cochrane databases were searched for relevant studies up to October 2020. The search strategy was conducted using both keywords and MeSH terms. Randomised controlled trials (RCTs) and observational studies that included patients from all age groups and any study design that reported on the prevalence of CKD in patients with diabetes mellitus were included. The pooled estimate for the prevalence of CKD in patients with diabetes was calculated using random-effect models with 95% confidence intervals (CIs).

RESULTS

A total of 489 citations were identified, of which only nine studies matched our inclusion criteria and were included in the meta-analysis. All of the studies used an observational study design covering a total of 59,395 patients with type 2 diabetes mellitus. The pooled estimate of the prevalence of CKD in patients with diabetes mellitus was 28.96% (95% CI: 19.80-38.11).

CONCLUSIONS

A high prevalence of CKD in patients with diabetes mellitus in the Middle East region was found. Further epidemiological studies are warranted in this area to have a better estimate of the prevalence of CKD among DM in the Middle East region.

Inhibition of α2-adrenoceptor is renoprotective in 5/6 nephrectomy-induced chronic kidney injury rats

In the present study, we investigated the renoprotective effects of long-term treatment with yohimbine, an α2-adrenoceptor inhibitor, in a 5/6 nephrectomy-induced chronic kidney disease (CKD) rat model. Male Sprague-Dawley rats were randomly allocated into the following groups: sham-operated, 5/6-nephrectomized (5/6 Nx), 5/6 Nx + low or high dose of yohimbine (0.3 or 3.0 mg/L in drinking water, respectively), and 5/6 Nx + hydralazine (250 mg/L in drinking water). The 5/6 Nx group presented with renal dysfunction, hypertension, noradrenaline overproduction, and histopathological injuries. Blood pressure decreased in both the yohimbine- and hydralazine-treated groups. Treatment with high dose of yohimbine, but not hydralazine, apparently attenuated urinary protein excretion and noradrenaline concentration of renal venous plasma. Renal fibrosis and upregulated fibrosis-related gene expression were suppressed by high dose of yohimbine. Furthermore, yohimbine, but not hydralazine, treatment ameliorated the urinary concentration ability. These findings suggest that long-term yohimbine treatment can be a useful therapeutic option to prevent the progression of CKD.

Examining the heterogeneity inexcess risks of coronary heart disease, stroke, dialysis, and lower extremity amputation associated with type 2 diabetes mellitus across demographic subgroups in an Asian population: A population-based matched cohort study

AIMS

To examine whether the excess risks of coronary heart disease (CHD), stroke, dialysis, and lower extremity amputation (LEA) associated with type 2 diabetes mellitus (T2DM) differ across age, sex, and ethnicity in Singapore.

METHODS

Using a 10-year administrative data, we matched individuals with T2DM using nearest neighbour matching, to those without, in 1:2 ratio. To examine whether the excess risks were heterogeneous across age, sex, and ethnicity, we generated interaction terms of age, sex, and ethnicity with T2DM status in Cox proportional hazard (PH) models.

RESULTS

The main analyses included ~1 million person years, comprising 66,099 and 120,485 individuals with and without T2DM, respectively. The associations of T2DM with CHD and dialysis, split into two time periods to address violation of PH assumption, were higher with older age in short-term but lower with older age in long-term. The association of T2DM with stroke and LEA were lower with older age. The associations of T2DM with CHD and stroke were also consistently higher in women than men. The associations of T2DM with LEA were higher in ethnic Malays than ethnic Chinese.

CONCLUSIONS

The excess risks of CHD, stroke, dialysis, and LEA associated with T2DM were heterogeneous across some demographic subgroups.

Effects of Chronic Kidney Disease and Uremic Toxins on Extracellular Vesicle Biology

Vascular calcification (VC) is a cardiovascular complication associated with a high mortality rate, especially in patients with diabetes, atherosclerosis or chronic kidney disease (CKD). In CKD patients, VC is associated with the accumulation of uremic toxins, such as indoxyl sulphate or inorganic phosphate, which can have a major impact in vascular remodeling. During VC, vascular smooth muscle cells (VSMCs) undergo an osteogenic switch and secrete extracellular vesicles (EVs) that are heterogeneous in terms of their origin and composition. Under physiological conditions, EVs are involved in cell-cell communication and the maintenance of cellular homeostasis. They contain high levels of calcification inhibitors, such as fetuin-A and matrix Gla protein. Under pathological conditions (and particularly in the presence of uremic toxins), the secreted EVs acquire a pro-calcifying profile and thereby act as nucleating foci for the crystallization of hydroxyapatite and the propagation of calcification. Here, we review the most recent findings on the EVs’ pathophysiological role in VC, the impact of uremic toxins on EV biogenesis and functions, the use of EVs as diagnostic biomarkers and the EVs’ therapeutic potential in CKD.

Uric acid level and kidney function: a cross-sectional study of the Korean national health and nutrition examination survey (2016-2017)

Kidney disease is expected to become the fifth leading cause of premature death globally by 2040. Uric acid level is a risk factor for kidney disease. The current study aims to investigate the association between uric acid levels and kidney function in the Korean population. The data of 11,042 participants of the 2016–2017 Korea National Health and Nutrition Examination Survey were analysed. The estimated glomerular filtration rate was calculated using the modification of diet in renal disease formula for Koreans. For each sex, uric acid levels were divided into five subsequent categories of increasing levels (Q1, Q2, Q3, Q4, and hyperuricemia). The association between uric acid level and kidney function was investigated using multiple logistic regression. The results showed that the higher the uric acid levels, the greater the odds of reduced kidney function in both sexes. In men, the adjusted odds ratios (95% confidence intervals) for reduced eGFR comparing the hyperuricemia group to the lowest serum uric acid quartile was 5.55 (3.27–9.44), and in women, the odds ratios (95% confidence intervals) was 7.52 (4.39–12.87). Normal weight or underweight in men and overweight in women, as well as diabetes mellitus, hypertension, and physical inactivity were highly associated with reduced kidney function. Our study revealed a dose–response relationship between uric acid levels and kidney function. Therefore, high uric acid level should be considered as a factor that is potentially related to kidney dysfunction in the Korean population.

Vitamin D Metabolism and Its Role in Mineral and Bone Disorders in Chronic Kidney Disease in Humans, Dogs and Cats

Some differences regarding Vitamin D metabolism are described in dogs and cats in comparison with humans, which may be explained by an evolutionary drive among these species. Similarly, vitamin D is one of the most important regulators of mineral metabolism in dogs and cats, as well as in humans. Mineral metabolism is intrinsically related to bone metabolism, thus disturbances in vitamin D have been implicated in the development of chronic kidney disease mineral and bone disorders (CKD-MBD) in people, in addition to dogs and cats. Vitamin D deficiency may be associated with Renal Secondary Hyperparathyroidism (RSHPT), which is the most common mineral disorder in later stages of CKD in dogs and cats. Herein, we review the peculiarities of vitamin D metabolism in these species in comparison with humans, and the role of vitamin D disturbances in the development of CKD-MBD among dogs, cats, and people. Comparative studies may offer some evidence to help further research about vitamin D metabolism and bone disorders in CKD.

The Cost-Effectiveness of Using Epoetin-Beta Versus Darbepoetin-Alfa for the Treatment of Anemia Among Chronic Hemodialysis Patients

Background and objective

Anemia is a common prognosis of chronic kidney disease (CKD). It is predominantly managed with synthetic erythropoietin. The principal objective of this study was to compare the cost-effectiveness of the use of short-acting erythropoietin with the long-acting one to maintain serum hemoglobin (Hb) concentration within the range of 10.5-12 g/dL.

Method

This was a retrospective cohort study involving patients diagnosed with stage 5 CKD according to the Saudi Society of Nephrology and Transplantation conducted at eight tertiary care centers in the Tabuk region, Saudi Arabia. We compared the cost-effectiveness of long-acting erythropoietin with the short-acting one. The decision analysis model and Markov model were established to simulate a cohort of 55-year-old patients to estimate the incremental cost and quality-adjusted life-year (QALY) for chronic hemodialysis patients (CHP) treated with either darbepoetin-alfa or epoetin-beta for at least nine months. The incremental cost per QALY was the main outcome marker for using both medications. Serum HB levels were monitored on a monthly basis and costs were calculated.

Results

A total of 291 CHP met our inclusion criteria; 194 of them were treated with darbepoetin-alfa while 97 were treated with epoetin-beta. The mean age was 56.3 ± 11.2 years for the darbepoetin-alfa group and 55.2 ± 7.8 years for the epoetin-beta cohort. The baseline serum Hb was 10.68 ± 0.98 g/dL for darbepoetin-alfa patients and 11.63 ± 0.32 g/dL for the epoetin-beta group (p=0.003). We observed a significant difference between the percentage of patients successfully treated with epoetin-beta and those managed with darbepoetin-alfa (80.4% vs. 63.92%, p=0.01) with considerably less cardiovascular side effects. The average annual cost per patient was estimated at $919.47 and $12,319.41 for epoetin-beta and darbepoetin-alfa respectively. Also, the average effectiveness was 0.58 for darbepoetin-alfa vs. 0.61 for epoetin-beta. The average cost-effectiveness ratio was $980.25 and $15,023.66 with an incremental cost difference of -$966 in favor of epoetin-beta compared to darbepoetin-alfa.

Conclusion

Based on our findings, treating anemia in hemodialysis patients using epoetin-beta is very cost-effective compared to managing them with darbepoetin-alfa.

Association of Diet Quality Indices with Longitudinal Changes in Kidney Function in U.S. Hispanics/Latinos: Findings from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

Background

Recent studies suggest an association between diet quality and incident CKD. However, Hispanics/Latinos were under-represented in these studies. We examined the relationship of diet quality with change in kidney function in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

Methods

Individuals who participated in HCHS/SOL visits 1 (2008-2011) and 2 (2014-2017) were analyzed (n=9921). We used Alternate Healthy Eating Index 2010 (AHEI-2010), Dietary Approaches to Stop Hypertension (DASH), and Mediterranean Diet (MeDS) scores as measures of dietary quality. Scores were calculated from two 24-hour dietary recalls administered at visit 1 and categorized into quartiles of each dietary score (higher quartiles correspond to a healthier diet). Kidney function was assessed at both visits using eGFR and urine albumin-creatinine ratio (UACR). Annualized change was computed as the difference in eGFR or UACR between visits divided by follow-up time in years. Weighted linear-regression models were used to examine the association between quartiles of each dietary quality index and annualized change in eGFR and UACR, adjusted for potential confounders.

Results

At visit 1, the mean (SD) age of participants was 41 (0.28) years, and 56% were female. The baseline mean eGFR was 107.1 ml/min per 1.73 m², and baseline median UACR was 6.1 mg/g. On average, eGFR declined by 0.65 ml/min per 1.73 m² per year, and UACR increased by 0.79 mg/g per year over a 6-year period. Lower AHEI-2010 quartiles were associated with eGFR decline in a dose-response manner (P trend=0.02). Higher AHEI-2010 quartiles showed a trend toward lower annualized change in UACR, but the result did not reach significance. Neither MeDS nor DASH scores were associated with eGFR decline or change in UACR.

Conclusions

Unhealthy diet, assessed at baseline by AHEI-2010, was associated with kidney-function decline over 6 years. Improving the quality of foods and nutrients according to the AHEI-2010 may help maintain kidney function in the Hispanic/Latino community.

Pre-hospital predictors of an adverse outcome among patients with dyspnoea as the main symptom assessed by pre-hospital emergency nurses - a retrospective observational study

Background

Dyspnoea is one of the most common reasons for patients contacting emergency medical services (EMS). Pre-hospital Emergency Nurses (PENs) are independently responsible for advanced care and to meet these patients individual needs. Patients with dyspnoea constitute a complex group, with multiple different final diagnoses and with a high risk of death. This study aimed to describe on-scene factors associated with an increased risk of a time-sensitive final diagnosis and the risk of death.

Methods

A retrospective observational study including patients aged ≥16 years, presenting mainly with dyspnoea was conducted. Patients were identified thorough an EMS database, and were assessed by PENs in the south-western part of Sweden during January to December 2017. Of 7260 missions (9% of all primary missions), 6354 were included. Among those, 4587 patients were randomly selected in conjunction with adjusting for unique patients with single occasions. Data were manually collected through both EMS- and hospital records and final diagnoses were determined through the final diagnoses verified in hospital records. Analysis was performed using multiple logistic regression and multiple imputations.

Results

Among all unique patients with dyspnoea as the main symptom, 13% had a time-sensitive final diagnosis. The three most frequent final time-sensitive diagnoses were cardiac diseases (4.1% of all diagnoses), infectious/inflammatory diseases (2.6%), and vascular diseases (2.4%). A history of hypertension, renal disease, symptoms of pain, abnormal respiratory rate, impaired consciousness, a pathologic ECG and a short delay until call for EMS were associated with an increased risk of a time-sensitive final diagnosis. Among patients with time-sensitive diagnoses, approximately 27% died within 30 days. Increasing age, a history of renal disease, cancer, low systolic blood pressures, impaired consciousness and abnormal body temperature were associated with an increased risk of death.

Conclusions

Among patients with dyspnoea as the main symptom, age, previous medical history, deviating vital signs, ECG pattern, symptoms of pain, and a short delay until call for EMS are important factors to consider in the prehospital assessment of the combined risk of either having a time-sensitive diagnosis or death.

Supplementary Information

Supplementary information accompanies this paper at 10.1186/s12873-020-00384-1.

Elevated alanine aminotransferase and low aspartate aminotransferase/alanine aminotransferase ratio are associated with chronic kidney disease among middle-aged women: a cross-sectional study

BACKGROUND

Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) to ALT ratio (AST/ALT ratio) have been shown to be related to non-alcoholic fatty liver disease or insulin resistance, which was associated with chronic kidney disease (CKD). However, it is unclear whether ALT and AST/ALT ratio are associated with CKD. In this study, we examined the relationship of ALT and AST/ALT ratio to CKD among middle-aged females in Japan.

METHODS

The present study included 29,133 women aged 40 to 64 years who had an annual health checkup in Japan during April 2013 to March 2014. Venous blood samples were collected to measure ALT, AST, gamma-glutamyltransferase (GGT), and creatinine levels. In accordance with previous studies, ALT > 40 U/L and GGT > 50 U/L were determined as elevated, AST/ALT ratio < 1 was regarded as low, and CKD was defined as estimated glomerular filtration rate < 60 mL/min/1.73 m² and/or proteinuria. Logistic regression model was used to calculate the odds ratio (OR) and 95% confidence interval (CI) for CKD.

RESULTS

"Elevated ALT and elevated GGT" and "elevated ALT and non-elevated GGT" significantly increased the OR for CKD when compared with "non-elevated ALT and non-elevated GGT" (OR: 2.56, 95% CI: 2.10-3.12 and OR: 2.24, 95% CI: 1.81-2.77). Compared with "AST/ALT ratio ≥ 1 and non-elevated GGT", "AST/ALT ratio < 1 and elevated GGT" and "AST/ALT ratio < 1 and non-elevated GGT" significantly increased the OR for CKD (OR: 2.73, 95% CI: 2.36-3.15 and OR: 1.68, 95% CI: 1.52-1.87). These findings still remained after adjustment for confounders.

CONCLUSIONS

Elevated ALT was associated with CKD regardless of GGT elevation. Moreover, low AST/ALT ratio was also associated with CKD independent of GGT elevation.

Association between weight status, metabolic syndrome, and chronic kidney disease among middle-aged and elderly Chinese

BACKGROUND AND AIMS

Obesity often initiates or coexists with certain metabolic abnormalities. This study sought to examine the independent and joint relations of weight and metabolic syndrome (MetS) with incident chronic kidney disease (CKD) among Chinese elderly people.

METHODS AND RESULTS

A total of 15,229 participants (mean age: 62.8 years) from the Dongfeng-Tongji cohort with complete baseline questionnaire and medical examination data were followed from 2008 to 2010 to 2013. All participants were categorized into four phenotypes: metabolically healthy non-overweight/obesity (MHNO), metabolically healthy overweight/obesity (MHO), metabolically unhealthy non-overweight/obesity (MUNO), metabolically unhealthy overweight/obesity (MUO). Multivariable-adjusted logistic regression models were applied to estimate the odds ratios (ORs) and confidence intervals (CIs) of four phenotypes with the risk of incident CKD, which was defined as estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m². A total of 1151 CKD cases were identified during a mean of 4.6-year follow-up. After adjusting for potential confounders, both overweight/obesity and MetS were associated with higher risk of CKD, and the ORs (95% CI) were 1.32 (1.15-1.52) and 1.50 (1.31-1.73), respectively. The risk of CKD was progressively higher in MHO (1.31, 1.09-1.57), MUNO (1.54, 1.22-1.93), and MUO (2.05, 1.73-2.42) as compared with MHNO phenotype, without significant multiplicative interaction between overweight/obesity and MetS (P_interaction = 0.906). These associations were slightly stronger among those aged >60 years or with baseline diabetes.

CONCLUSION

Both overweight/obesity and MetS were associated with an increased risk of CKD. It is worth noting that MHO and MUNO also have an elevated risk. Maintaining both normal weight and healthy metabolic profile is recommended.

Nutritional Guideline for the Management of Mexican Patients with CKD and Hyperphosphatemia

Chronic kidney disease (CKD) represents a serious concern for the Mexican population since the main predisposing diseases (diabetes, hypertension, etc.) have a high prevalence in the country. The development of frequent comorbidities during CKD such as anemia, metabolic disorders, and hyperphosphatemia increases the costs, symptoms, and death risks of the patients. Hyperphosphatemia is likely the only CKD comorbidity in which pharmaceutical options are restricted to phosphate binders and where nutritional management seems to play an important role for the improvement of biochemical and clinical parameters. Nutritional interventions aiming to control serum phosphate levels need to be based on food tables, which should be specifically elaborated for the cultural context of each population. Until now, there are no available food charts compiling a high amount of Mexican foods and describing phosphorus content as well as the phosphate to protein ratio for nutritional management of hyperphosphatemia in CKD. In this work, we elaborate a highly complete food chart as a reference for Mexican clinicians and include charts of additives and drug phosphate contents to consider extra sources of inorganic phosphate intake. We aim to provide an easy guideline to contribute to the implementation of more nutritional interventions focusing on this population in the country.

Association of Infection With Human Papillomavirus and Development of End-Stage Kidney Disease in Taiwan

IMPORTANCE

The association between human papillomavirus (HPV) infection status and the natural process of kidney diseases has been neglected as an area of research. Further studies are needed to clarify factors that may alter the progression of end-stage kidney disease (ESKD).

OBJECTIVE

To describe the rates of ESKD among patients with and without HPV infection.

DESIGN, SETTING, AND PARTICIPANTS

In this nationwide, population-based retrospective cohort study, data were collected from the National Health Insurance Research Database of Taiwan. A total of 76 088 individuals with HPV infection were enrolled from January 1, 2000, to December 31, 2012, and compared with a control group of 76 088 individuals who had never been diagnosed with HPV infection (at a 1:1 ratio propensity-score matched by age, sex, index year, and comorbidities) in the context of the risk of developing ESKD. Statistical analysis was performed between November 2019 and July 2020.

EXPOSURES

HPV infection was defined according to the International Classification of Diseases, Ninth Revision, Clinical Modification codes.

MAIN OUTCOMES AND MEASURES

The main outcome was ESKD, as recorded in the Catastrophic Illness Patients database. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs, with the control group as a reference.

RESULTS

Of 152 176 individuals (79 652 [52.3%] women; mean [SD] age, 34.4 [19.1] years), 76 088 individuals (50.0%) had HPV and 463 individuals (0.3%) developed ESKD. Incidence of ESKD was lower in individuals with HPV history than in those without HPV history (3.64 per 10 000 person-years vs 4.80 per 10 000 person-years). In the fully adjusted multivariate Cox proportional hazards regression model, individuals with a history of HPV infection had a significant decrease in risk of ESKD (adjusted HR, 0.72; 95% CI, 0.60-0.87) after adjusting for demographic characteristics, comorbidities, and comedications. In the subgroup analysis, individuals ages 50 to 64 years with HPV infection had a statistically significantly lower risk of ESKD compared with individuals ages 50 to 64 years with no HPV infection (adjusted HR, 0.48; 95% CI, 0.34-0.68; P < .001), while there was no significant reduction in risk for the other age groups (ie, 0-19, 20-49, and 65-100 years).

CONCLUSIONS AND RELEVANCE

In this study, a history of HPV infection was associated with a lower risk of subsequent ESKD. The mechanism behind this protective association remains uncertain. Future studies are required to clarify the possible biological mechanisms.

Association of exposure to phthalates and environmental phenolics with markers of kidney function: Korean National Environmental Health Survey (KoNEHS) 2015-2017

Increasing number of consumer chemicals have been associated with chronic kidney disease (CKD) in human populations. However, many studies that investigated estimated glomerular filtration rate (eGRF) as an outcome reported inconsistent associations. In the present study, we employed a subset (n = 1292) of a nationally representative adult population participating in Korean National Environmental Health Survey (KoNEHS) 2015-2017, and assessed associations of major phthalates, bisphenol A (BPA), and parabens with both eGRF and albuminuria. In order to address a potential collider issue, a covariate-adjusted standardization method was applied, in addition to the conventional creatinine-correction, for adjusting urine dilution. Regardless of adjustment method, urinary DEHP metabolites showed significant positive associations with albumin to creatinine ratio (ACR). In addition, urinary metabolites of other heavy molecular weight phthalates such as MCOP and MCNP showed significant positive associations with ACR in the female population, but only following the covariate-adjusted standardization. For eGFR, conventional creatinine-correction resulted in positive associations with most of measured phthalate metabolites. However, with the covariate-adjusted standardization, most of positive associations with eGFR disappeared, and instead, significant negative associations were observed for MnBP, BPA, and EtP. Secondary analysis following stratification by CKD status, as well as principal component analysis (PCA), generally supported the observed associations. The present observations highlight the importance of urine dilution adjustment method for association studies on eGFR, and suggest potential effects of several consumer chemicals on adverse kidney function among humans.

Health Care Resource Use and Cost Burden of Chronic Kidney Disease in Patients With Chronic Liver Disease: A Real-World Claims Analysis

Chronic Liver Disease (CLD) is associated with an increased risk of chronic kidney disease (CKD). However, the health care burden of CKD in the CLD spectrum is unknown. We aimed to evaluate the health care use and cost burdens associated with CKD in patients with CLD in the United States by using real-world claims data. We analyzed data from the Truven Health MarketScan Commercial Claims database from 2010 to 2015. A total of 19,664 patients with CLD with or without comorbid CKD were identified using International Classification of Diseases, Ninth Revision, codes and matched 1:1 by sociodemographic characteristics and comorbidities using propensity scores. Total and service-specific unadjusted and adjusted health care parameters were analyzed for the 12 months following an index date selected at random to capture whole disease burdens. In CLD, comorbid CKD was associated with a higher annual number of claims per person (CKD vs. no CKD, 69 vs. 55) and higher total annual median health care costs (CKD vs. no CKD, $21,397 vs. $16,995). A subanalysis stratified by CKD category showed that health care use and cost burden in CLD increased with disease stage, with a peak 12-month median cost difference of $77,859 in patients on dialysis. The adjusted per person annual health care cost was higher for CKD cases compared to controls ($35,793 vs. $24,048, respectively; P < 0.0001). Stratified by the type of CLD, the highest between-group adjusted cost differences were for cirrhosis, viral hepatitis, hemochromatosis, and nonalcoholic fatty liver disease. Conclusion: CKD is a cost multiplier in CLD. The CKD health care burden in liver disease differs by the type of CLD. Improved CKD screening and proactive treatment interventions for at-risk patients can limit the excess burden associated with CKD in patients with CLD.

Hyperhomocysteinemia Concurrent with Metabolic Syndrome Is Independently Associated with Chronic Kidney Disease among Community-Dwelling Adults in an Urban Korean Population

Elevated homocysteine (Hcy) levels and metabolic syndrome (MetS) are associated with chronic kidney disease (CKD). We investigated the combined effects of hyperhomocysteinemia (HHcy) and MetS on CKD among community-dwelling adults in an urban area of South Korea. We also identified the combination of HHcy and individual MetS components associated with the maximal risk of CKD. A retrospective cross-sectional study involving 19,311 health examinees between 2 January 2011 and 31 December 2015 was conducted. The participants were divided into four groups—namely, the HHcy−/MetS−, HHcy−/MetS+, HHcy+/MetS−, and HHcy+/MetS+ groups. CKD was defined as a low eGFR <60 mL/min/1.73 m² or albuminuria. The HHcy+/MetS+ group had a higher risk of CKD than the HHcy−/MetS+ group (odds ratio (OR): 1.750, p = 0.002 for males; OR: 3.224, p < 0.001 for females). The HHcy+/MetS+ group had a higher CKD risk than the HHcy+/MetS− group; however, the difference was not statistically significant (OR: 1.070, p = 0.712 for males; OR: 1.847, and p < 0.074 for females). HHcy concurrent with MetS increased the CKD risk. Among the combinations of HHcy and MetS components, the coexistence of HHcy and central obesity had the greatest effect on CKD. Therefore, the timely detection and treatment of HHcy and MetS are important for preventing CKD.

Uremic Toxins Affect Erythropoiesis during the Course of Chronic Kidney Disease: A Review

Chronic kidney disease (CKD) is a global health problem characterized by progressive kidney failure due to uremic toxicity and the complications that arise from it. Anemia consecutive to CKD is one of its most common complications affecting nearly all patients with end-stage renal disease. Anemia is a potential cause of cardiovascular disease, faster deterioration of renal failure and mortality. Erythropoietin (produced by the kidney) and iron (provided from recycled senescent red cells) deficiencies are the main reasons that contribute to CKD-associated anemia. Indeed, accumulation of uremic toxins in blood impairs erythropoietin synthesis, compromising the growth and differentiation of red blood cells in the bone marrow, leading to a subsequent impairment of erythropoiesis. In this review, we mainly focus on the most representative uremic toxins and their effects on the molecular mechanisms underlying anemia of CKD that have been studied so far. Understanding molecular mechanisms leading to anemia due to uremic toxins could lead to the development of new treatments that will specifically target the pathophysiologic processes of anemia consecutive to CKD, such as the newly marketed erythropoiesis-stimulating agents.

Chronic Kidney Disease as Oxidative Stress- and Inflammatory-Mediated Cardiovascular Disease

Generating reactive oxygen species (ROS) is necessary for both physiology and pathology. An imbalance between endogenous oxidants and antioxidants causes oxidative stress, contributing to vascular dysfunction. The ROS-induced activation of transcription factors and proinflammatory genes increases inflammation. This phenomenon is of crucial importance in patients with chronic kidney disease (CKD), because atherosclerosis is one of the critical factors of their cardiovascular disease (CVD) and increased mortality. The effect of ROS disrupts the excretory function of each section of the nephron. It prevents the maintenance of intra-systemic homeostasis and leads to the accumulation of metabolic products. Renal regulatory mechanisms, such as tubular glomerular feedback, myogenic reflex in the supplying arteriole, and the renin–angiotensin–aldosterone system, are also affected. It makes it impossible for the kidney to compensate for water–electrolyte and acid–base disturbances, which progress further in the mechanism of positive feedback, leading to a further intensification of oxidative stress. As a result, the progression of CKD is observed, with a spectrum of complications such as malnutrition, calcium phosphate abnormalities, atherosclerosis, and anemia. This review aimed to show the role of oxidative stress and inflammation in renal impairment, with a particular emphasis on its influence on the most common disturbances that accompany CKD.

Canadian Senior Renal Leaders Community of Practice: Vulnerable Populations With Chronic Kidney Disease-Evidence to Inform Policy

Purpose:

Low socioeconomic status, race, ethnicity, and rural/remote populations are all associated with disparities in access, care, and outcomes for chronic kidney disease (CKD). There have been different interventions supported by Canadian renal programs to address these disparities. This article reviews the evidence for impact of strategies to reduce inequities experienced by vulnerable populations living with or at risk of CKD and to collate and share interprovincial targeted interventions through the newly formed “Canadian Senior Renal Leaders Community of Practice” focused on translating evidence into clinical practice and policy.

Source of Information:

A literature search of Medline, CINAHL, PubMed, and Google Scholar from 2008 to 2018 identified 13 reports of processes and interventions that have been implemented in Australia, Canada, and the United States to reduce inequities in CKD care and can be categorized into 3 broad areas: (1) early screening and prevention, (2) disease management and dialysis, and (3) pretransplant. Web sites from each Canadian jurisdiction and from Canadians Seeking Solutions and Innovations to Overcome Chronic Kidney Disease (Can-SOLVE CKD) Network were used to assess the current state of Canadian initiatives.

Methods:

Reviews were completed to gather information on renal initiatives for vulnerable populations, including (1) identification of populations that experience disparities in access to care or in outcomes in the context of CKD prevention and treatment and (2) interventions that have been implemented to reduce disparities in access, care, and outcomes for vulnerable populations with CKD. A current state summary of Canadian initiatives related to vulnerable populations was conducted through a review of publicly available information, including a review of renal program Web sites and a review of current projects related to vulnerable populations that are part of Can-SOLVE CKD. Can-SOLVE CKD is a Canadian Institutes of Health Research Strategy for Patient-Oriented Research (CIHR-SPOR) funded research network to transform the care of people affected by kidney disease.

Key Findings:

Interventions to improve inequities in access to CKD screening, disease management, and care are successful when developed with community engagement, provided to the patient in their own environment, and tailored to specific populations. Many provincial renal programs have implemented initiatives to support vulnerable populations with or at risk of CKD. Current projects funded through CIHR SPOR focus on underserved populations and involve partnerships with Indigenous populations. Many renal programs in Canada had or were in the process of implementing interventions to support vulnerable populations with CKD; however, information about the initiatives were not readily available online despite a strong interest and opportunity to support interprovincial knowledge sharing. Despite this common interest, little information is systematically shared between Canadian jurisdictions to support interprovincial sharing to promote evidence-informed policy and program development. Efforts will be made through the newly formed Canadian Senior Renal Leaders Community of Practice to collaborate and share learnings to inform future program and policy development, implementation, and evaluation.

Limitations:

As this was not a systematic review, literature search only encompassed studies published in English between 2008 and 2018. It is possible that populations and interventions were overlooked during the search and through the screening process. Furthermore, the controversial definition of “vulnerable” and literature that only came from Canada, the United States, and Australia limits the generalizability of this review.

Regulatory T Cells as a Novel Candidate for Cell-Based Therapy in Kidney Disease

Kidney disease is a significant health concern worldwide. Ineffective treatment can lead to disastrous consequences, such as organ failure and death. Research has turned to cell-based therapy, but has yet to produce an effective and reliable treatment for kidney disease. To address this problem, we examined four datasets of gene expression profiles from diseased and healthy kidney tissue in humans, mice, and rats. Differentially expressed genes (DEGs) were screened and subjected to enrichment analyses. Up-regulated genes in diseased kidney tissue were significantly enriched in pathways associated with regulatory T cells (Tregs). Analysis with the xCell tool showed that Tregs were generally increased in diseased kidney tissue in all species. To validate these results in vivo, kidneys were removed from mice with Adriamycin-induced nephropathy, and histology confirmed increase of Tregs. Furthermore, Tregs were adoptively transferred from healthy mice into mice with kidney injury, restoring normal structure to the damaged kidneys. Treg cells that were co-cultured with M2c macrophages exhibited up-regulation of chemokine receptors CCR2, CCR5, CCR7, CD62L, and CX3CR1. This may be the mechanism by which M2c cells enhance the migration of Tregs to the site of inflammation. We propose that Tregs may be an effective, novel candidate for cell-based therapy in pre-clinical kidney injury models.

Long work hours and decreased glomerular filtration rate in the Korean working population

OBJECTIVES

We studied the association between long working hours and decreased kidney function, which was determined using estimated glomerular filtration rate (eGFR), among the working population in South Korea.

METHODS

We analysed nationally representative cross-sectional data for 20 851 Korean workers ≥20 years of age. A negative binomial regression model was used to test differences in the prevalence of chronic kidney disease (eGFR <60 mL/min/1.73 m²) among workers divided into groups according to weekly working hours (<30, 30-40, 41-51 and ≥52 hours/week). Multivariate linear regression analysis was performed to investigate the association between weekly working hours and eGFR, with adjustments made for age, sex/gender, income, education, shift work, occupation, smoking, alcohol use, hypertension, diabetes mellitus, body mass index, systolic blood pressure, fasting blood glucose and total serum cholesterol.

RESULTS

A 1-hour increase in weekly working hours was associated with 0.057 mL/min/1.73 m² (95% CI 0.005 to 0.109) decrease in eGFR among participants who worked ≥52 hours/week. Among participants without hypertension or diabetes, a 1-hour increase in weekly working hours was significantly associated with 0.248 and 0.209 mL/min/1.73 m² decrease in eGFR among participants who worked 30-40 hours/week and 41-51 hours/week, respectively.

CONCLUSION

Long working hours are associated with decreased kidney function. We expect that our findings could call for more research regarding this association and provide policy-oriented perspectives.

Renoprotective Effects of a Novel Receptor-Interacting Protein Kinase 2 Inhibitor, AS3334034, in Uninephrectomized Adriamycin-Induced Chronic Kidney Disease Rats

Renal inflammation is a final common pathway of chronic kidney disease (CKD), and its progression can be used to effectively gauge the degree of renal dysfunction. Inflammatory mechanisms contribute to glomerulosclerosis and tubulointerstitial fibrosis, which are hallmarks of CKD leading to end-stage renal disease. Receptor-interacting protein kinase 2 (RIP2) is largely committed to nucleotide-binding oligomerization domain signaling as a direct effector and transmits nuclear factor-κB (NF-κB)-mediated proinflammatory cytokine production. In the present study, we hypothesized that if inflammation via RIP2 and NF-κB signaling plays an important role in renal failure, then the anti-inflammatory effect of RIP2 inhibitors should be effective in improving CKD. To determine its pharmacologic potency, we investigated the renoprotective properties of the novel RIP2 inhibitor AS3334034 [7-methoxy-6-(2-methylpropane-2-sulfonyl)-N-(4-methyl-1H-pyrazol-3-yl)quinolin-4-amine] in uninephrectomized adriamycin-induced CKD rats. Six weeks' repeated administration of AS3334034 (10 mg/kg, once daily) significantly reduced urinary protein excretion and prevented the development of glomerulosclerosis and tubulointerstitial fibrosis. In addition, AS3334034 showed beneficial effects on renal function, as demonstrated by a decrease in levels of plasma creatinine and blood urea nitrogen and attenuation of a decline in creatinine clearance. Furthermore, AS3334034 significantly attenuated inflammation, renal apoptosis, and glomerular podocyte loss. These results suggest that the RIP2 inhibitor AS3334034 suppresses the progression of chronic renal failure via an anti-inflammatory effect and is therefore potentially useful in treating patients with CKD. SIGNIFICANCE STATEMENT: The receptor-interacting protein kinase 2 (RIP2) inhibitor AS3334034 suppresses the progression of chronic renal failure via an anti-inflammatory effect, suggesting that the nucleotide-binding oligomerization domain-RIP2 axis might play a crucial role in the pathogenesis of inflammatory kidney diseases. AS3334034 is expected to be potentially useful in the treatment of patients with chronic kidney disease.

Comparative Disease Assessment: a multi-causal approach for estimating the burden of mortality

Background

The Comparative Risk Assessment (CRA) framework comprehensively evaluates the impact of exposure to risk factors on health populations using the counterfactual causal approach.

Methods

We propose a framework, Comparative Disease Assessment (CDA), for assessing the impact of exposure to morbidity from some diseases on health outcomes, particularly death from other (relevant) diseases. This framework has been developed following the ideas of the CRA framework and using the widely accepted concept that exposure to morbidity is usually a risk factor for health outcomes (morbidity/mortality) related to other diseases. Our framework uses a counterfactual and not a categorical approach when attributing the burden of health outcomes to potential causes.

Results

This paper describes the different steps and assumptions required to implement the CDA framework, and an illustrative example is used considering diabetes mellitus morbidity as a risk factor for death from heart diseases.

Conclusions

One advantage of the CDA framework is that it can be applied using multi-causal death registries. Some assumptions are needed to implement it in order to avoid biases, but at least it can provide preliminary estimations of the impact of exposure to diseases as risk factors for deaths from other diseases. Another main advantage is that the burden of deaths is no longer attributed to a single cause, the underlying cause, as it is almost always done. Finally, this framework provides information on the pattern of comorbidity in a (sub)population of subjects who is about to die. These patterns can be used as a reference for alternative patterns of the general population or patterns of other specific subpopulations.

Drugs Commonly Applied to Kidney Patients May Compromise Renal Tubular Uremic Toxins Excretion

In chronic kidney disease (CKD), the secretion of uremic toxins is compromised leading to their accumulation in blood, which contributes to uremic complications, in particular cardiovascular disease. Organic anion transporters (OATs) are involved in the tubular secretion of protein-bound uremic toxins (PBUTs). However, OATs also handle a wide range of drugs, including those used for treatment of cardiovascular complications and their interaction with PBUTs is unknown. The aim of this study was to investigate the interaction between commonly prescribed drugs in CKD and endogenous PBUTs with respect to OAT1-mediated uptake. We exposed a unique conditionally immortalized proximal tubule cell line (ciPTEC) equipped with OAT1 to a panel of selected drugs, including angiotensin-converting enzyme inhibitors (ACEIs: captopril, enalaprilate, lisinopril), angiotensin receptor blockers (ARBs: losartan and valsartan), furosemide and statins (pravastatin and simvastatin), and evaluated the drug-interactions using an OAT1-mediated fluorescein assay. We show that selected ARBs and furosemide significantly reduced fluorescein uptake, with the highest potency for ARBs. This was exaggerated in presence of some PBUTs. Selected ACEIs and statins had either no or a slight effect at supratherapeutic concentrations on OAT1-mediated fluorescein uptake. In conclusion, we demonstrate that PBUTs may compete with co-administrated drugs commonly used in CKD management for renal OAT1 mediated secretion, thus potentially compromising the residual renal function.

Hemodialysis in the Compact Nations of the US Affiliated Pacific: History and Health Care Implications

Background: The epidemic of non-communicable disease in the Compact nations of the US Affiliated Pacific Islands and the associated renal complications drive the demand for hemodialysis. Limited healthcare budgets and a lack of trained human health resources in these areas make hemodialysis a challenging undertaking that may require significant sacrifices in competing health care priorities. Methods: Two nephrologists who developed hemodialysis in the US Affiliated Pacific Islands provide its history. Cost estimates of hemodialysis for the Compact nations are collected from a 2014 hemodialysis feasibility report. The experiences and outcomes of current hemodialysis centers in the United States and other island nations provide a framework by which to assess the potential benefit and impact of hemodialysis in the Compact nations. Discussion: A consideration of how and why different stakeholders value hemodialysis will be crucial because they will drive the public's response to the institutionalization of any new intervention or the cessation of any existing intervention like hemodialysis. Conclusion: Updated cost estimates for dialysis clinics and data on renal disease rates in the Compact nations will be necessary to make informed decisions about hemodialysis in the current health systems. In the meantime, it is essential to enhance current medical interventions and public health strategies to prevent kidney disease and decrease the risks for kidney failure. Such preventive interventions must be culturally appropriate, effective, cost-efficient, and sustainable in the unique context of the Pacific.

Association between lifestyle factors and decreased kidney function in older adults: a community-based cross-sectional analysis of the Taipei City elderly health examination database

BACKGROUND

Impaired kidney function is the hallmark of chronic kidney disease (CKD), and is associated with increased risk of all-cause mortality in the elderly. In the present cross-sectional population-based study, we aimed to evaluate the associations between lifestyle factors (exercise habit, alcohol consumption, smoking history, and betel nut chewing) and decreased kidney function.

METHODS

The data from the Taipei City Elderly Health Examination Database (2006 to 2012) were extracted. Associations between risk factors and reduced estimated Glomerular filtration rate (eGFR) were evaluated by regression and stratification analyses.

RESULTS

A total of 297,603 participants were included in the final analysis, and 29.7% of them had reduced eGFR. Smoking was significantly associated with an elevated risk of reduced eGFR. While, physical exercise conferred to a significantly decreased adjusted odds ratio (aOR) in reduced eGFR (regular exercise, aOR = 0.79; occasional exercise, aOR = 0.87). Furthermore, the protective effect of exercise habit against reduced eGFR was not affected by comorbid conditions, such as hypertension, diabetes, obesity, and cardiovascular disease.

CONCLUSIONS

Engaging in physical exercise was beneficially associated with reduced eGFR in older individuals. Longitudinal or prospective studies are warranted for confirmation and extrapolation of the current findings.

High particulate matter 2.5 levels and ambient temperature are associated with acute lung edema in patients with nondialysis Stage 5 chronic kidney disease

BACKGROUND

Numerous studies have shown that exposure to air pollution, especially particulate matter (PM) with a diameter <2.5 μm (PM2.5), was associated with various diseases. We tried to determine the impact of PM2.5 and other weather factors on acute lung edema in patients with Stage 5 nondialysis chronic kidney disease (CKD Stage 5-ND).

METHODS

In total, 317 CKD Stage 5-ND (estimated glomerular filtration rate 6.79 ± 4.56 mL/min) patients residing in central Taiwan who developed acute lung edema and initiated long-term dialysis were included in this case-crossover study. Pearson's correlation test was used to examine the relationship of acute lung edema cases with PM2.5 levels and ambient temperature separately.

RESULTS

The average PM2.5 level within the 7-day period correlated with acute lung edema incidence in the fall [adjusted odds ratio (OR) 3.23, P = 0.047] and winter (adjusted OR 1.99, P < 0.001). In winter, even a 3-day exposure to PM2.5 was associated with increased risk (adjusted OR 1.55, P < 0.001). The average temperatures within 3 days in spring and summer were correlated positively with the risk (adjusted OR 2.77 P < 0.001 and adjusted OR 2.72, P < 0.001, respectively). In the fall and winter, temperatures were correlated negatively with the risk (adjusted OR 0.36, P < 0.001 and adjusted OR 0.54, P < 0.001, respectively).

CONCLUSIONS

A high PM2.5 level was associated with an increased risk of acute lung edema. High ambient temperature in hot seasons and low ambient temperature in cold seasons were also associated with increased risk. It is essential to educate these patients to avoid areas with severe air pollution and extreme ambient temperature.

Nephroprotective Potential of Mesenchymal Stromal Cells and Their Extracellular Vesicles in a Murine Model of Chronic Cyclosporine Nephrotoxicity

Background

Cell therapies and derived products have a high potential in aiding tissue and organ repairing and have therefore been considered as potential therapies for treating renal diseases. However, few studies have evaluated the impact of these therapies according to the stage of chronic kidney disease. The aim of this study was to evaluate the renoprotective effect of murine bone marrow mesenchymal stromal cells (BM-MSCs), their extracellular vesicles (EVs) and EVs-depleted conditioned medium (dCM) in an aggressive mouse model of chronic cyclosporine (CsA) nephrotoxicity in a preventive and curative manner.

Methods

After 4 weeks of CsA-treatment (75 mg/kg daily) mice developed severe nephrotoxicity associated with a poor survival rate of 25%, and characterized by tubular vacuolization, casts, and cysts in renal histology. BM-MSC, EVs and dCM groups were administered as prophylaxis or as treatment of CsA nephrotoxicity. The effect of the cell therapies was analyzed by assessing renal function, histological damage, apoptotic cell death, and gene expression of fibrotic mediators.

Results

Combined administration of CsA and BM-MSCs ameliorated the mice survival rates (6-15%), but significantly renal function, and histological parameters, translating into a reduction of apoptosis and fibrotic markers. On the other hand, EVs and dCM administration were only associated with a partial recovery of renal function or histological damage. Better results were obtained when used as treatment rather than as prophylactic regimen i.e., cell therapy was more effective once the damage was established.

Conclusion

In this study, we showed that BM-MSCs induce an improvement in renal outcomes in an animal model of CsA nephrotoxicity, particularly if the inflammatory microenvironment is already established. EVs and dCM treatment induce a partial recovery, indicating that further experiments are required to adjust timing and dose for better long-term outcomes.

Intraglomerular Monocyte/Macrophage Infiltration and Macrophage-Myofibroblast Transition during Diabetic Nephropathy Is Regulated by the A2B Adenosine Receptor

Diabetic nephropathy (DN) is considered the main cause of kidney disease in which myofibroblasts lead to renal fibrosis. Macrophages were recently identified as the major source of myofibroblasts in a process known as macrophage–myofibroblast transition (MMT). Adenosine levels increase during DN and in vivo administration of MRS1754, an antagonist of the A_2B adenosine receptor (A_2BAR), attenuated glomerular fibrosis (glomerulosclerosis). We aimed to investigate the association between A_2BAR and MMT in glomerulosclerosis during DN. Kidneys/glomeruli of non-diabetic, diabetic, and MRS1754-treated diabetic (DM+MRS1754) rats were processed for histopathologic, transcriptomic, flow cytometry, and cellular in vitro analyses. Macrophages were used for in vitro cell migration/transmigration assays and MMT studies. In vivo MRS1754 treatment attenuated the clinical and histopathological signs of glomerulosclerosis in DN rats. Transcriptomic analysis demonstrated a decrease in chemokine-chemoattractants/cell-adhesion genes of monocytes/macrophages in DM+MRS1754 glomeruli. The number of intraglomerular infiltrated macrophages and MMT cells increased in diabetic rats. This was reverted by MRS1754 treatment. In vitro cell migration/transmigration decreased in macrophages treated with MRS1754. Human macrophages cultured with adenosine and/or TGF-β induced MMT, a process which was reduced by MRS1754. We concluded that pharmacologic blockade of A_2BAR attenuated some clinical signs of renal dysfunction and glomerulosclerosis, and decreased intraglomerular macrophage infiltration and MMT in DN rats.

miR-451 Loaded Exosomes Are Released by the Renal Cells in Response to Injury and Associated With Reduced Kidney Function in Human

Micro-RNAs (miRs) encapsulated inside urinary exosomes (uEs) have the potential as early biomarkers. Previously, we reported that a rise in uE miR-451 predicted albuminuria in diabetic rats; however, whether the rise was protective or detrimental, and occurred in response to injury or general hyperglycemia, was unknown. To address this, we studied both human and rat models of renal disease. In humans, uE miR-451 was approximately twofold higher in subjects with early-stage chronic kidney disease (CKD; serum creatinine < 2.0 mg/dl; n = 28), as compared to age-matched healthy controls (n = 23), and had a significant negative correlation with estimated glomerular filtration rate (eGFR) (r² = −0.10, p = 0.01). Subgroup analysis of CKD subjects showed that those without diabetes had slightly (∼30%) but significantly higher uE miR-451 as compared to those with diabetes, with no differences in albumin excretion, eGFR, serum sodium, and potassium. Using human proximal tubule (hPT) cells, we found that locked nucleic acid (LNA) inhibition of miR-451 resulted in a significant increase in the messenger RNA (mRNA) expression of kidney-injury-associated miR-451 targets, e.g., CAB39, TBX1, and YWHAZ, as compared to treatment with a control LNA. Moreover, hPT cells and their secreted exosomes showed an increase in miR-451 in response to mechanical injury but not high glucose (20 versus 5 mM). For further proof of concept, in diabetic rats, we showed that atorvastatin (AT), a treatment proven to attenuate renal injury without affecting systemic glucose levels, reduced uE miR-451 with the concomitant restoration of renal miR-451. These data elucidate the stimuli for renal miR-451 expression and exosomal release and support its role as a therapeutic target and early biomarker for renal injury in humans.

Low lung function and the risk of incident chronic kidney disease in the Malmö Preventive Project cohort

BACKGROUND

Although the prevalence of kidney disease is higher in those with reduced lung function, the longitudinal relationship between low lung function and future risk of chronic kidney disease (CKD) has not been widely explored.

METHODS

Baseline lung function was assessed in 20,700 men and 7325 women from 1974 to 1992. Mean age was 43.4 (±6.6) and 47.5 (±7.9) for men and women respectively. Sex-specific quartiles of FEV1 and FVC (L) were created (Q4: highest, reference) and the cohort was also divided by the FEV1/FVC ratio (≥ or < 0.70). Cox proportional hazards regression was used to determine the risk of incident CKD events (inpatient or outpatient hospital diagnosis of CKD) in relation to baseline lung function after adjustment for various confounding factors.

RESULTS

Over 41 years of follow-up there were 710 and 165 incident CKD events (main diagnosis) in men and women respectively. Low FEV1 was strongly associated with future risk of CKD in men (Q1 vs Q4 adjusted HR: 1.46 (CI:1.14-1.89), p-trend 0.002). Similar findings were observed for FVC in men (1.51 (CI:1.16-1.95), p-trend 0.001). The adjusted risks were not found to be significant in women, for either FEV1 or FVC. FEV1/FVC < 0.70 was not associated with increased incidence of CKD in men or women.

CONCLUSION

Low FEV1 and FVC levels at baseline are a risk factor for the development of future incident CKD in men. Monitoring kidney function in those with reduced vital capacity in early life could help with identifying those at increased risk of future CKD.

Integrative metagenomic and metabolomic analyses reveal severity-specific signatures of gut microbiota in chronic kidney disease

Chronic kidney disease (CKD) is a serious healthcare dilemma, associated with specific changes in gut microbiota and circulating metabolome. Yet, the functional capacity of CKD microbiome and its intricate relationship with the host metabolism at different stages of disease are less understood. Methods: Here, shotgun sequencing of fecal samples and targeted metabolomics profiling of serum bile acids, short- and medium-chain fatty acids, and uremic solutes were performed in a cohort of CKD patients with different severities and non-CKD controls. Results: We identified that levels of 13 microbial species and 6 circulating metabolites were significantly altered across early to advanced stages or only in particular stage(s). Among these, Prevotella sp. 885 (decreased) was associated with urea excretion, while caproic acid (decreased) and p-cresyl sulfate (elevated) were positively and negatively correlated with the glomerular filtration rate, respectively. In addition, we identified gut microbial species linked to changes in circulating metabolites. Microbial genes related to secondary bile acid biosynthesis were differentially abundant at the early stage, while pathway modules related to lipid metabolism and lipopolysaccharide biosynthesis were enriched in the CKD microbiome at the advanced stage, suggesting that changes in microbial metabolism and host inflammation may contribute to renal health. Further, we identified metagenomic and metabolomic markers to discriminate cases of different severities from the controls, among which Bacteroides eggerthii individually was of particular value in early diagnosis. Conclusions: Our dual-omics data reveal the connections between intestinal microbes and circulating metabolites perturbed in CKD, which may be of etiological and diagnostic importance.

Associations between urinary cadmium levels, blood pressure, and hypertension: the ESTEBAN survey

Cadmium is inconsistently associated with blood pressure (BP) and hypertension. Our study focuses to understand the association between urinary cadmium levels, blood pressure, and hypertension in a French representative sample. Our study included 2015 subjects from the ESTEBAN survey (2014-2015) with measured urinary cadmium. Associations between natural logarithm-transformed cadmium levels and BP (systolic (SBP) and diastolic blood pressure (DBP)) were performed by adjusted linear regression models. Associations between cadmium and hypertension were performed by adjusted logistic regression models. Models were stratified by gender, smoking habits, body mass index (BMI), and kidney function categories. Men present higher SBP (131.7 vs. 121.5 mmHg, p < 0.0001) and DBP (78.9 vs. 74.7 mmHg, p < 0.0001) in comparison to women. Creatinine-adjusted urinary cadmium levels (0.48 vs. 0.39 μg/L, p < 0.0001) were higher in hypertensive subjects. Nevertheless, no difference was observed after adjustment for age, gender, and smoking habits. No correlation between urinary cadmium, BP, and hypertension was observed in overall population. Stratified models showed inverse correlations between urinary cadmium and hypertension among obese (OR = 0.39, 95% CI [0.21-0.57], p = 0.0009), chronic kidney function (OR = 0.68 95%CI [0.75-0.97], p = 0.003), and current smokers (OR = 0.78, 95% CI [0.64-0.92], p = 0.04). A correlation between urinary cadmium levels, BP, and hypertension is observed in subpopulations. Nevertheless, directions and significance of these associations differs by gender, BMI, smoking, and kidney function categories.

Comparison of Renal Effects of Ezetimibe-Statin Combination versus Statin Monotherapy: A Propensity-Score-Matched Analysis

Neither lowering of blood lipid levels nor treatment with statins definitively improves renal outcomes. Ezetimibe, a non-statin antilipidemic agent, is known to not only decrease blood lipid levels but also reduce inflammatory response and activate autophagy. We evaluated the effect of adding ezetimibe to a statin on renal outcome compared with statin monotherapy by analyzing longitudinal data of 4537 patients treated with simvastatin 20 mg plus ezetimibe 10 mg (S + E) or simvastatin 20 mg alone (S) for more than 180 days. A propensity-score-based process was used to match baseline characteristics, medical history, and estimated glomerular filtration rate (eGFR) between S + E and S groups. Changes in serum creatinine and incidence of renal events, defined as doubling of serum creatinine to ≥1.5 mg/dL or occurrence of end-stage renal disease after the first day of treatment initiation, were compared between the groups. Among 3104 well-matched patients with a median follow-up of 4.2 years, the S + E group showed a significantly lower risk of renal events than the S group (hazard ratio 0.58; 95% CI 0.35-0.95, P = 0.032). In addition, the S + E group tended to preserve renal function compared with the S group throughout follow-up, as assessed by serum creatinine changes (P-values for time–group interactions <0.001). These data support the beneficial effects on renal function when combining ezetimibe with a statin.

Loss of Arhgef11 in the Dahl Salt-Sensitive Rat Protects Against Hypertension-Induced Renal Injury

Arhgef11 is a Rho-guanine nucleotide exchange factor that was previously implicated in kidney injury in the Dahl salt-sensitive (SS) rat, a model of hypertension-related chronic kidney disease. Reduced Arhgef11 expression in an SS-Arhgef11^SHR-minimal congenic strain (spontaneously hypertensive rat allele substituted for S allele) significantly decreased proteinuria, fibrosis, and improved renal hemodynamics, without impacting blood pressure compared with the control SS (SS-wild type). Here, SS-Arhgef11^-/- and SS-wild type rats were placed on either low or elevated salt (0.3% or 2% NaCl) from 4 to 12 weeks of age. On low salt, starting at week 6 and through week 12, SS-Arhgef11^-/- animals demonstrated a 3-fold decrease in proteinuria compared with SS-wild type. On high salt, beginning at week 6, SS-Arhgef11^-/- animals demonstrated >2-fold lower proteinuria from weeks 8 to 12 and 30 mm Hg lower BP compared with SS-wild type. To better understand the molecular mechanisms of the renal protection from loss of Arhgef11, both RNA sequencing and discovery proteomics were performed on kidneys from week 4 (before onset of renal injury/proteinuria between groups) and at week 12 (low salt). The omics data sets revealed loss of Arhgef11 (SS-Arhgef11^-/-) initiates early transcriptome/protein changes in the cytoskeleton starting as early as week 4 that impact a number of cellular functions, including actin cytoskeletal regulation, mitochondrial metabolism, and solute carrier transporters. In summary, in vivo phenotyping coupled with a multi-omics approach provides strong evidence that increased Arhgef11 expression in the Dahl SS rat leads to actin cytoskeleton-mediated changes in cell morphology and cell function that promote kidney injury, hypertension, and decline in kidney function.

Exploring the putative interactions between chronic kidney disease and chronic periodontitis

Chronic kidney disease (CKD) and chronic periodontitis (CP) are both common diseases, which are found disproportionately comorbid with each other and have been reported to have a detrimental effect on the progression of each respective disease. They have an overlap in risk factors and both are a source of systemic inflammation along with a wide selection of immunological and non-specific effects that can affect the body over the lifespan of the conditions. Previous studies have investigated the directionality of the relationship between these two diseases; however, there is a lack of literature that has examined how these diseases may be interacting at the localized and systemic level. This review discusses how oral microorganisms have the ability to translocate and have distal effects and provides evidence for microbial involvement in a systemic disease. Furthermore, it summarizes the reported local and systemic effects of CKD and CP and discusses how the interaction of these effects may be responsible for directionality associations reported.

Initial assessment and ongoing monitoring of lysosomal acid lipase deficiency in children and adults: Consensus recommendations from an international collaborative working group

BACKGROUND

Lysosomal acid lipase (LAL) deficiency is an ultra-rare, progressive, autosomal recessive disorder. Functional mutations in LIPA, the gene that encodes LAL, result in accumulation of cholesteryl esters and triglycerides in hepatocytes and in the macrophages of the intestines, vascular endothelial system, and numerous other organs. LAL deficiency has a broad clinical spectrum; children and adults can present with dyslipidemia, liver enzyme elevations, hepatosplenomegaly, hepatic steatosis, liver fibrosis and/or cirrhosis, and vascular disease, which may lead to significant morbidity and premature mortality in some patients. Given the systemic involvement and the wide range of healthcare specialists who manage patients with LAL deficiency, there is a need for guidelines to assess and monitor disease involvement.

OBJECTIVES

To provide a set of recommendations for the initial assessment and ongoing monitoring of patients with LAL deficiency to help physicians in various disciplines effectively manage the disease based on the observed presentation and progression in each case.

METHODS

A group of internationally recognized healthcare specialists with expertise in clinical genetics, pathology, hepatology, gastroenterology, cardiology, and lipidology convened to develop an evidence-based consensus of best practices for the initial assessment and ongoing monitoring of children and adults with LAL deficiency, regardless of treatment status; infants with LAL deficiency have been excluded from these guidelines because they require specialized care.

RESULTS

The authors present guidance for the assessment and monitoring of patients with LAL deficiency based on age and disease manifestations that include the hepatic, cardiovascular, and gastrointestinal systems. A schedule for ongoing monitoring of disease progression is provided. In addition, the need to establish an interdisciplinary and integrated care team to optimize the approach to managing this systemic disease is highlighted.

CONCLUSIONS

There is currently no published guidance on the assessment and monitoring of patients with LAL deficiency. These consensus recommendations for the initial assessment and ongoing monitoring of children and adults with LAL deficiency are intended to help improve the management of these patients.

Association of obesity with chronic kidney disease in elderly patients with nonalcoholic fatty liver disease

BACKGROUND/AIMS

This study investigated an association between obesity and impaired renal functions in elderly patients with nonalcoholic fatty liver disease (NAFLD) and evaluated the risk factors for chronic kidney disease (CKD) in these patients.

MATERIALS AND METHODS

A cross-sectional study was performed involving 515 elderly patients (≥ 60 years old) with NAFLD. Demographics, body mass index (BMI), medical history, and laboratory parameters were compared for groups stratified by obesity (≥ 28 kg/m2) or CKD. An association between obesity and CKD was analyzed, and a multivariate logistic regression analysis was conducted for risk factors associated with CKD.

RESULTS

In the overall population, 28.7% were obese and 54.8% had CKD; there were more women (58.8%) than men. The prevalence of hypertension and diabetes was similar between the obese and nonobese groups and between the CKD and non-CKD groups. Obese patients had significantly higher levels of serum uric acid and estimated glomerular filtration rates when compared with the nonobese group. When compared with those without CKD, patients with CKD were significantly older in addition to having higher BMI and serum uric acid levels. The multivariate logistic regression analysis indicated that CKD was positively associated with age, BMI, and serum uric acid levels.

CONCLUSION

Elderly obese patients with NAFLD are at a higher risk of CKD. NAFLD patients with advanced age, greater BMI, or higher serum uric acid levels are more prone to developing CKD. The renal function of NAFLD patients should be closely monitored.

Sarcopenic obesity is associated with a faster decline in renal function in people with type 2 diabetes

AIM

To evaluate the association between sarcopenic obesity and the decline in estimated GFR in people with type 2 diabetes.

METHODS

We enrolled 745 people with type 2 diabetes (mean age 64.6 years, 53.6% men). Body composition was evaluated using dual-energy X-ray absorptiometry. Skeletal muscle index, calculated as appendicular non-fat mass (kg) divided by height squared (m² ), was used to determine sarcopenia. Sarcopenic obesity was defined as the coexistence of sarcopenia and a ratio of android to gynoid fat mass greater than the median values in each gender. The association of sarcopenic obesity both with the annual rate of decline in estimated GFR and a >30% decline in estimated GFR was evaluated using multivariate linear regression models and Cox proportional hazard models, respectively.

RESULTS

Participants with sarcopenic obesity were at an increased risk of a high annual rate of decline in estimated GFR, even after adjustment for the confounding variables (standardized β = -0.228, P <0.001). Sarcopenic obesity was also significantly associated with risk of a >30% decline in estimated GFR (hazard ratio 4.52, 95% CI 2.16-9.47; P < 0.01) in multivariate model.

CONCLUSIONS

Sarcopenic obesity evaluated by dual energy X-ray absorptiometry is associated with a faster decline in renal function in people with type 2 diabetes.

Gut Microbiota as Diagnostic Tools for Mirroring Disease Progression and Circulating Nephrotoxin Levels in Chronic Kidney Disease: Discovery and Validation Study

The interplay of the gut microbes with gut-producing nephrotoxins and the renal progression remains unclear in large human cohort. Significant compositional and functional differences in the intestinal microbiota (by 16S rRNA gene sequencing) were noted among 30 controls and 92 (31 mild, 30 moderate and 31 advanced) patients at different chronic kidney disease (CKD) stages (discovery cohort). A core CKD-associated microbiota consisted of 7 genera (Escherichia_Shigella, Dialister, Lachnospiraceae_ND3007_group, Pseudobutyrivibrio, Roseburia, Paraprevotella and Ruminiclostridium) and 2 species (Collinsella stercoris and Bacteroides eggerthii) were identified to be highly correlated with the stages of CKD. Paraprevotella, Pseudobutyrivibrio and Collinsella stercoris were superior in discriminating CKD from the controls than the use of urine protein/creatinine ratio, even at early-stage of disease. The performance was further confirmed in a validation cohort comprising 22 controls and 76 peritoneal dialysis patients. Bacterial genera highly correlated with indoxyl sulfate and p-cresyl sulfate levels were identified. Prediction of the functional capabilities of microbial communities showed that microbial genes related to the metabolism of aromatic amino acids (phenylalanine, tyrosine, and tryptophan) were differentially enriched among the control and different CKD stages. Collectively, our results provide solid human evidence of the impact of gut-metabolite-kidney axis on the severity of chronic kidney disease and highlight a usefulness of specific gut microorganisms as possible disease differentiate marker of this global health burden.

Causal inference for the effect of environmental chemicals on chronic kidney disease

The impacts of environmental chemicals on the decline of kidney function have been suggested by a limited number of statistical and animal studies. Thus, those exposures may be modifiable risk factors for chronic kidney disease. Some of the chemicals, such as Perfluoroalkyl acid (PFA), are pervasive throughout our environment, determining their health effects is an important public health concern. In this study, we examined cross-sectional data from the 2009–2010 cycle of the National Health and Nutrition Examination Survey (NHANES) using a statistical causal inference method-generalized propensity score method, to determine the links between concentrations of several major environmental chemicals and kidney function measured by the estimated glomerular filtration rate (eGFR). Various generalized propensity score estimation methods including Hirano-Imbens, additive spline, and a generalized additive model were compared. Among the examined environmental chemicals, each of the statistical models used associated an increase in PFA concentration with a decline in eGFR. We conclude that PFA is a modifiable risk factor for chronic kidney disease and the statistical causal method produces credible results in estimating the effect of chemical exposures on a continuous measure of kidney functions with an observational dataset.