Nontraditional risk factors for cardiovascular disease in patients with chronic kidney disease

Is lipid management effective for all stages of CKD?

Patients with chronic kidney disease (CKD) suffer from high rates of cardiovascular morbidity and mortality. The general approach to traditional cardiovascular risk factor modification via dyslipidemia control has not been thoroughly tested in patients with all stages of CKD. In this article, we review the evidence for statin therapy in patients at various stages of CKD, including patients with CKD on dialysis and patients with kidney transplants.

Risk factors for atherosclerosis in patients with chronic kidney disease: recognition and management

Heart disease is the most common cause of death in patients with chronic kidney disease (CKD), particularly in those receiving dialysis. Atherosclerosic cardiovascular (CV) disease (CVD) accounts for a large number of these deaths. Atherosclerosis is accelerated in patients with CKD due predominantly to the high prevalence of traditional CVD risk factors in the CKD population. CKD aggravates pre-existent traditional risk factors such as hypertension and dyslipidemia due to secondary renal parenchymal hypertension and secondary dyslipidemia. In addition, a variety of non-traditional risk factors that occur commonly in CKD patients contribute to CV risk. Recent studies suggest that CKD itself may be an independent risk factor for CVD, particularly coronary heart disease (CHD). Many therapies aimed at CV risk factor modification that have been successful in reducing CV risk in the general population are less effective or ineffective in favorably modifying CV risk in CKD.

Fibroblast growth factor 23 and Klotho: physiology and pathophysiology of an endocrine network of mineral metabolism

The metabolically active and perpetually remodeling calcium phosphate-based endoskeleton in terrestrial vertebrates sets the demands on whole-organism calcium and phosphate homeostasis that involves multiple organs in terms of mineral flux and endocrine cross talk. The fibroblast growth factor (FGF)-Klotho endocrine networks epitomize the complexity of systems biology, and specifically, the FGF23-αKlotho axis highlights the concept of the skeleton holding the master switch of homeostasis rather than a passive target organ as hitherto conceived. Other than serving as a coreceptor for FGF23, αKlotho circulates as an endocrine substance with a multitude of effects. This review covers recent data on the physiological regulation and function of the complex FGF23-αKlotho network. Chronic kidney disease is a common pathophysiological state in which FGF23-αKlotho, a multiorgan endocrine network, is deranged in a self-amplifying vortex resulting in organ dysfunction of the utmost severity that contributes to its morbidity and mortality.

Effects of residual renal function on left ventricle and analysis of related factors in patients with hemodialysis

BACKGROUND

Left ventricular hypertrophy (LVH) and systolic dysfunction would predict the mortality of patients undergoing maintenance hemodialysis. The cause of LVH is usually related to the increase of total peripheral vascular resistance and overloading volume. The presence of residual diuresis enables greater control of the volume. This study evaluated the effects of residual renal function (RRF) on the left ventricle and analyzed the related factors involved in hemodialysis patients.

METHODS

A total of 59 hemodialysis patients were classified into two groups. The patients in the RRF (RRF+) group had a urine volume greater than 200 mL/24 h, and the patients in the non-RRF (RRF-) group had a urine volume less than 200 mL/24 h. B-type natriuretic peptide (BNP), blood total homocysteine (tHcy), and blood biochemical indexes were determined for the patients in both groups. Echocardiography and Doppler tests were performed to determine the cardiac indexes.

RESULTS

LVH and systolic dysfunction in the RRF+ group were less severe than those in the RRF- group. The concentration of tHcy and BNP in patients with RRF was decreased in comparison with those without RRF. The concentration of tHcy and BNP was positively correlated with the residual diuresis.

CONCLUSIONS

There were distinct ventricular geometric patterns and different functional performances between RRF+ and RRF- groups. The presence of residual diuresis had a beneficial effect on the left ventricular function in hemodialysis patients.

Plasma cytokines, glomerular filtration rate and adipose tissue cytokines gene expression in chronic kidney disease (CKD) patients

BACKGROUND AND AIM

Systemic inflammation is a hallmark of chronic kidney disease (CKD) and obesity represents a major risk factor for CKD. We investigated the relationship between plasma interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) and the glomerular filtration rate (GFR) in 75 stage 2-5 CKD patients.

METHODS AND RESULTS

We studied the steady-state relationship between plasma and subcutaneous adipose tissue (SAT) gene expression of the same cytokines in 19 patients and in 17 well-matched healthy subjects (HS) and compared SAT gene expression of these cytokines and of two additional cytokines (IL-1β and IL-8) in CKD patients and in HS. Plasma IL-6 and TNF-α were higher in CKD patients than in HS (P < 0.001). IL-6 was similarly increased in patients with mild, moderate and severe CKD and largely independent of the GFR (r = -0.03, P = NS). TNF-α was inversely related to GFR, which was the first factor in rank (β = -0.37, P = 0.001) explaining the variability in TNF-α in CKD. SAT messenger RNA (mRNA) levels of IL-6, TNF-α, IL- β and IL-8 were similar in CKD patients and in HS. Plasma and SAT mRNA levels of IL-6 and TNF-α levels were largely unrelated.

CONCLUSIONS

Plasma IL-6 rises early in CKD and does not show any further increase at more severe stages of CKD, whereas TNF-α is inversely associated with the GFR indicating a substantial difference in the dynamics of the relationship between these cytokines and renal function. Cytokines are not overexpressed in SAT in these patients, and circulating IL-6 and TNF-α are dissociated from the corresponding mRNA levels in SAT, both in CKD patients and in HS.

Attenuation of kidney injuries maintains serum sulfatide levels dependent on hepatic synthetic ability: a possible involvement of oxidative stress

Serum sulfatides are the major glycosphingolipids in lipoproteins. Although serum sulfatides are mainly synthesized and secreted by the liver, they are significantly decreased when the kidneys are impaired. Our recent experimental study using a murine protein-overload nephropathy model suggested a hypothetical mechanism whereby serum sulfatides were reduced due to kidney dysfunction. This was the result of decreased hepatic expression of a sulfatide synthetic enzyme, cerebroside sulfotransferase (CST), which is associated with systemic enhancement of oxidative stress. However, there is a possibility that the experimental process, protein-overload itself, directly affected the sulfatide metabolism and oxidative stress in the liver. To determine whether kidney dysfunction actually reduces the hepatic synthesis of sulfatides via oxidative stress, we examined sulfatide levels, the hepatic content of metabolic sulfatide enzymes, and the degree of oxidative stress in protein-overload mice subjected to renoprotective therapy using clofibrate, a representative hypolipidemic medicine. Protein-overload mice exhibited marked kidney injuries, enhancement of hepatic oxidative stress, decreased levels of serum and hepatic sulfatides, and decreased expression of hepatic CST. The clofibrate treatment attenuated kidney damage and hepatic oxidative stress while maintaining serum/hepatic sulfatide levels and hepatic CST content in the mice. Because clofibrate monotherapy without protein-overload treatment only minimally affected these hepatic parameters, the hepatic synthesis of sulfatides appeared to be strongly influenced by kidney dysfunction and subsequent oxidative stress. This study suggests that the crosstalk between kidney dysfunction and hepatic sulfatide metabolism is mediated by oxidative stress. These results should help to understand the phenomenon in patients with end-stage kidney disease.

Association between moderate renal insufficiency and cardiovascular events in a general population: Tehran lipid and glucose study

BACKGROUND

Chronic kidney disease(CKD) has been proposed as a risk factor for cardiovascular disease (CVD). There is conflicting evidence among community based studies regarding the association between CKD and CVD. Furthermore, in order to assess the possible interaction between CKD and BMI, we also examined the association between CKD and CVD, across different BMI categories.

METHODS

The risk of CVD events was evaluated in a large cohort of participants selected from the Tehran Lipid and Glucose Study. Participants(mean age, 47.4 years) free of previous CVD were followed up for 9.1 years. GFR ml/min per 1.73 m(2) was estimated using the MDRD formula.

RESULTS

Of the 6,209 participants, 22.2%(1381) had CKD with eGFR ml/min per 1.73 m(2) <60 at baseline. Almost all of them (99%) were in stage 3a. Moderate renal insufficiency only predicted CVD outcomes independently when we adjusted for age and sex. After further adjustment, the presence of moderate CKD lost its statistical significance to confer an independent increased risk of CVD events with a hazard ratio of: HR: 1.14, CI 95% 0.91-1.42. Furthermore, when participants were categorized according to CKD status and BMI groups, after further adjustment, no interaction was found(P = 0.2).

CONCLUSION

CKD was not an independent risk factor for CVD events in a community-based study in a Tehranian population and the higher prevalence of CVD in subjects with mild to moderate renal insufficiency might be due to the co-occurrence of traditional CVD risk factors in this group.

The effect of combined calcium and cholecalciferol supplementation on bone mineral density in elderly women with moderate chronic kidney disease

AIMS

To examine the effect of combined calcium and vitamin D3 supplementation on bone mineral density (BMD) inpatients with chronic kidney disease (CKD).

METHODS

We performed a post-hoc analysis of the DECALYOS II, a 2-year randomized, double-blind, placebo-controlled study of 610 women randomized to: calcium-vitamin D3 fixed combination, calcium plus vitamin D3 separate combination, or placebo. Both active treatment groups received the same daily amount of calcium (1,200 mg) and vitamin D3 (800 IU). BMD of the distal radius was measured by single X-ray absorptiometry at baseline, 12 and 24 months.

RESULTS

At baseline 47.2%, 36.4% and 16.4% of the study population had an eGFR ≥ 60, 45 -59, and < 45 ml/min/1.73 m2, respectively. Both active regimens vs. placebo markedly increased serum 25-hydroxyvitamin D levels from baseline in all eGFR groups (p 0.22 for all time points).

CONCLUSION

Combined calcium and vitamin D3 supplementation was effective in reducing rate of BMD loss in women with moderate CKD.

Kidney function and cognitive and functional decline in elderly adults: findings from the Singapore longitudinal aging study

OBJECTIVES

To investigate whether lower estimated glomerular filtration rate (eGFR) or chronic kidney disease (CKD) was associated with subsequent cognitive and instrumental activity of daily living (IADL) decline in a prospective cohort study.

DESIGN

Prospective cohort study, followed for up to 4 years.

SETTING

General community.

PARTICIPANTS

One thousand three hundred fifteen adults aged 55 and older from the Singapore Longitudinal Aging Study.

MEASUREMENTS

Baseline data included eGFR levels, presence of CKD (eGFR < 60 mL/min per 1.73 m(2) ), and known confounders. Cognitive decline was defined as a drop of 2 or more points on the Mini-Mental State Examination (MMSE) and functional decline as a drop of 2 or more points in IADL score.

RESULTS

Decreasing levels of eGFR and the presence of CKD were associated with greater odds of cognitive decline at follow-up independent of confounding risk factors in multivariate analyses: estimated 14% increment in odds of cognitive decline per 10 mL/min/1.73 m(2) decrease in eGFR (odds ratio = 1.94, 95% confidence interval = 1.23-3.05; P = .004 for CKD vs non-CKD). Similar associations were found in a cognitively normal subgroup (MMSE > 23) at baseline. In the whole sample, CKD, but not eGFR, was found to be significantly associated with higher risk of IADL decline.

CONCLUSION

CKD in older persons was significantly associated with cognitive and functional decline. Future research should target the development and evaluation of strategies to delay or prevent cognitive decline and physical disability in elderly adults with impaired kidney function.

Kidney and heart interactions during cardiorenal syndrome: a molecular and clinical pathogenic framework

The heart and kidney are physiologically interconnected. Cardiorenal syndrome (CRS) is a pathological disorder where acute or chronic dysfunction in one organ may induce dysfunction in the other one. Although classical studies have proposed a role for hypertension, dyslipidemia and endothelial dysfunction, CRS should be considered as a complex molecular interplay of neurohumoral pathway activation including the sympathetic nervous system, the renin angiotensin aldosterone axis, the endothelin system and the arginine vasopressin system. This activation may induce vascular inflammation, oxidative stress, accelerated atherosclerosis, cardiac hypertrophy and both myocardial and intrarenal fibrosis with progression of CRS treatment. More recently, epigenetics has opened new pathogenic molecular routes for CRS. This will lead to a more rapid development of novel, safe and effective clinical therapies.

Left ventricular hypertrophy is associated with inflammation in sodium loaded subtotal nephrectomized rats

The pathological influences of inflammation on left ventricular hypertrophy (LVH) were studied in subtotal nephrectomized (SNx) rats after 0.3% NaCl loading for 5 weeks. We found that mild hypertension, increased plasma levels of creatinine, inorganic phosphate, asymmetric dimethylarginine (ADMA), and parathyroid hormone (PTH) were observed in the present SNx rats without LVH. In the present study, the NaCl-loaded SNx (SNx + NaCl) rats were characterized by significant LVH and hypertension with aggravated values of all the parameters. We further confirmed that glomerular sclerosis, tubulointerstitial fibrosis, and inflammatory cell infiltration into the tubulointerstitial area, observed in the SNx rats, were more severely caused in the SNx + NaCl rats. In addition, plasma interleukin-6 (IL-6) levels in the SNx + NaCl rats were significantly increased compared to those in the SNx rats. These findings indicated that NaCl-loaded SNx rats developed LVH and hypertension, which were accompanied with increased plasma levels of PTH, creatinine, inorganic phosphorus, ADMA, and IL-6. Thus, these results suggest that inflammation as well as endothelial dysfunction would be correlated with LVH as non-traditional risk factors at the early stage in the present renal failure model.

Risk of cardiovascular disease and chronic kidney disease in diabetic patients with non-alcoholic fatty liver disease: just a coincidence?

Non-alcoholic fatty liver disease (NAFLD) is estimated to afflict ~20-30% of the general population, and over 70% of the patients with Type 2 diabetes. Given the expected rise in the prevalence of obesity and diabetes, NAFLD will be, if not already there, an epidemic. The consequences of NAFLD are numerous, and range from progression to chronic liver disease with its associated morbidity and mortality, to worsening insulin resistance and Type 2 diabetes, to being a contributor to both cardiovascular disease (CVD) and chronic kidney disease (CKD). NAFLD is, therefore, a complex problem with implications far beyond the liver. This review focuses on the rapidly expanding body of clinical evidence suggesting that NAFLD is associated with an increased prevalence and incidence of both CVD and CKD in patients with diabetes. This association appears to be independent of obesity, hypertension, and other potential confounding factors. However, given the heterogeneity and small number of observational studies, further research is urgently required to corroborate the prognostic role of NAFLD in the development and progression of CVD and CKD among patients with diabetes, and to further elucidate the complex and intertwined mechanisms that link NAFLD with these adverse outcomes.

Risk of chronic kidney disease in patients with non-alcoholic fatty liver disease: is there a link?

Non-alcoholic fatty liver disease (NAFLD) has emerged as a growing public health problem worldwide. Increasing recognition of the importance of NAFLD and its association with the features of the metabolic syndrome has stimulated an interest in its putative role in the development and progression of chronic kidney disease (CKD). Accumulating evidence suggests that NAFLD and CKD share many important cardio-metabolic risk factors and common pathogenetic mechanisms and that NAFLD is associated with an increased prevalence and incidence of CKD. This association appears to be independent of obesity, hypertension, and other potentially confounding factors, and it occurs both in patients without diabetes and in those with diabetes. Although further research is needed to establish a definitive conclusion, these observations raise the possibility that NAFLD is not only a marker of CKD but also might play a part in the pathogenesis of CKD, possibly through the systemic release of several pro-inflammatory/pro-coagulant mediators from the steatotic/inflamed liver or through the contribution of NAFLD itself to insulin resistance and atherogenic dyslipidemia. However, given the heterogeneity and small number of observational longitudinal studies, further research is urgently required to corroborate the prognostic significance of NAFLD for the incidence of CKD, and to further elucidate the complex and intertwined mechanisms that link NAFLD and CKD. If confirmed in future large-scale prospective studies, the potential adverse impact of NAFLD on kidney disease progression will deserve particular attention, especially with respect to the implications for screening and surveillance strategies in the growing number of patients with NAFLD.

Hemodialysis induces p66(shc) gene expression in nondiabetic humans: correlations with oxidative stress and systemic inflammation

OBJECTIVE

Oxidative stress and inflammation characterize hemodialysis (HD) and are associated with malnutrition, cardiovascular disease, and poor clinical outcome. p66(shc) stimulates oxidative stress and atherogenesis. The objective of the present study was to assess p66(shc) expression levels in HD and their associations with inflammatory and oxidative stress markers.

DESIGN

p66(shc) messenger ribonucleic acid (mRNA) was compared with systemic oxidative stress and inflammation markers in control subjects and patients on HD before and after a single HD session in a cross-sectional analysis.

SETTING

Outpatient hemodialysis unit.

PATIENTS

The study included stable HD patients (n = 21, men/women: 18/3) who were on HD 3 times per week for a minimum of 8 weeks; age-matched control subjects (n = 22, men/women:17/5).

MAIN OUTCOME MEASURE

mRNA levels of p66(shc), tumor necrosis factor α (TNF-α), and pentraxin 3 (PTX3), p66(shc) protein levels in white blood cells, lipid peroxidation (in the form of plasma thiobarbituric acid-reactive substance [TBARS]) and serum C-reactive protein.

RESULTS

In patients on dialysis, of the p66(shc), TNF-α, and PTX3 mRNAs, p66(shc) protein levels were higher (P < .05) than in control subjects, as well as plasma TBARS and C-reactive protein (P < .05). p66(shc) mRNA directly correlated with TBARS (r = 0.69, P = .0005) and with TNF-α mRNA (r = 0.63, P = .003). These associations were confirmed in the whole study population (TBARS: r = 0.541, P = .0003; TNF-α: r = 0.581, P < .0001), whereas in the control group only the positive association between p66(shc) and TNF-α was detected. TNF-α was directly correlated with PTX3 both in HD patients (r = 0.72, P = .0005) and in the whole study group (r = 0.678, P < .0001). The dialysis session affected neither p66(shc) and TNF-α mRNA nor p66(shc) protein expression, whereas it further increased (P = .002) PTX3 mRNA. As compared with predialysis levels, TBARS were reduced (P < .05) after dialysis. In these conditions, p66(shc) remained directly correlated with TNF-α (r = 0.901, P < .0001).

CONCLUSIONS

Increased p66(shc) gene expression correlates with TNF-α mRNA and with levels of markers of oxidative stress in HD. We suggest a novel link between HD-associated inflammation and p66(shc) gene expression contributing to systemic oxidative stress.

Impact of seropositivity to Chlamydia pneumoniae and anti-hHSP60 on cardiovascular events in hemodialysis patients

Autoimmunity to heat shock protein 60 (HSP60) has been related to atherosclerosis. Chlamydia pneumoniae (CP), the most studied infectious agent implicated in promoting atherosclerosis, produces a form of HSP60, which can induce an autoimmune response, due to high antigenic homology with human HSP60 (hHSP60). In this study, we evaluated the correlations among anti-hHSP60 antibodies, CP infection, and cardiovascular disease (CVD) in a high-risk population, such as patients undergoing hemodialysis (HD). Thirty-two patients (67.9 ± 13.9 years; male/female, 23:9) on regular HD were enrolled. Global absolute cardiovascular risk (GCR) was assessed using the Italian CUORE Project's risk charts, which evaluate age, gender, smoking habits, diabetes, systolic blood pressure, and serum cholesterol. The occurrence of cardiovascular events during a 24-month follow-up was recorded. Seropositivity to CP and the presence of anti-hHSP60 antibodies were tested by specific enzyme-linked immunosorbent assays. Inflammation was assessed by measurement of C-reactive protein (CRP) serum levels. Fifteen healthy sex and age-matched (61.9 ± 9.5 years; male/female, 11:4) subjects were the control group. Fifteen of 32 patients resulted seropositive for CP. CP + patients were older than CP-, while they did not differ for GCR, CRP, and dialytic parameters. CVD incidence was significantly higher in CP+ (9 CP+ vs 2 CP-, p < 0.05). Cox analysis recognized that the incidence of CVD was independently correlated with seropositivity to CP (HR, 7.59; p = 0.01; 95% CI = 1.63-35.4). On the other hand, there were no significant differences in anti-hHSP60 levels among CP+, CP- and healthy subjects: 18.11 μg/mL (14.8-47.8), 31.4 μg/mL (23.2-75.3), and 24.72 μg/mL (17.7-41.1), respectively. Anti-hHSP60 did not correlate to GCR, CRP, and incidence of CVD. In conclusion, our data suggest that anti-hHSP60 autoimmune response is not related to CP infection and CP-related CVD risk in HD patients.

Plasma S100A12 level is associated with cardiovascular disease in hemodialysis patients

BACKGROUND AND OBJECTIVES

S100A12 is an endogenous receptor ligand for advanced glycation end products. Cardiovascular disease remains a major cause of morbidity and mortality in patients with chronic kidney disease. In this study, we report cross-sectional data on 550 hemodialysis patients and assess the relationship between plasma S100A12 level and cardiovascular disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A cross-sectional study of 550 maintenance hemodialysis patients was conducted. We investigated the past history of cardiovascular disease and quantified the plasma level of S100A12 protein in all participants.

RESULTS

Plasma S100A12 level was higher in hemodialysis patients with cardiovascular disease (n=197; 33.8 ± 28.1 ng/ml) than in those without it (n=353; 20.2 ± 16.1 ng/ml; P<0.001). In multivariate logistic regression analysis, the plasma S100A12 level (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.13 to 1.44; P<0.001) was identified as an independent factor associated with the prevalence of cardiovascular disease. The other factors associated with the prevalence of cardiovascular diseases were the presence of diabetes mellitus (OR, 2.81; 95% CI, 1.79 to 4.41; P < 0.001) and high-sensitivity CRP level (OR, 1.02; 95% CI, 1.00 to 1.05; P=0.046). Furthermore, the plasma S100A12 level (OR, 1.30; 95% CI, 1.09 to 1.54; P=0.004) was significantly associated with cardiovascular disease even in hemodialysis patients without diabetes mellitus (n=348).

CONCLUSIONS

These results suggest that the plasma S100A12 protein level is strongly associated with the prevalence of cardiovascular disease in hemodialysis patients.

Hypertension in moderate-to-severe nondiabetic CKD patients

High blood pressure can be both a cause and a consequence of chronic kidney disease and will contribute to an unfavorable renal and cardiovascular (CV) prognosis. Both in the general population and in hypertensive patients, the presence of chronic kidney disease is associated with a high prevalence of CV disease. Elevated blood pressure and the amount of albumin present in urine are the 2 most relevant factors facilitating the progression of chronic kidney disease in hypertensive patients. Therapeutic attitudes that must be considered when chronic kidney disease is present include the simultaneous performance of CV and renal protection.

The diabetic CKD patient--a major cardiovascular challenge

The diabetic patient with chronic kidney disease (CKD) is at very high risk of cardiovascular disease (CVD). Primary and secondary CVD prevention is of major importance and should be targeted at both traditional cardiovascular risk factors and risk factors specific for patients with CKD, such as albuminuria, anaemia and CKD--mineral and bone disorder. However, treatment goals have largely been derived from clinical trials including patients with no or only mild CKD and may not be generalizable to patients with advanced renal disease. Moreover, in patients on renal replacement therapy, the association between traditional CVD risk factors and the incidence of CVD may be reversed, and pharmaceutical interventions that are beneficial in the general population may be ineffective or even harmful in this high-risk population. Those involved in the delivery of care to patients with diabetes and CKD need to be aware of these issues and should adopt an individualised approach to treatment.

Does concealed chronic kidney disease predict survival of older patients discharged from acute care hospitals?

We aimed at verifying whether unrecognized chronic kidney disease (CKD) (i.e., reduced estimated glomerular filtration rate in spite of normal serum creatinine) has prognostic significance in an unselected population of older patients discharged from 11 acute care hospitals located throughout Italy. Our series consisted of 396 participants aged 70 and older. Estimated glomerular filtration rate (eGFR) was calculated by the Modification of Diet in Renal Disease (MDRD) study equation. We compared three groups: Normal renal function (normal serum creatinine levels and normal eGFR), concealed (normal serum creatinine levels and reduced eGFR), or overt (increased creatinine levels and reduced eGFR) renal failure. The relationship between renal function and 1-year mortality was evaluated using Kaplan-Meier curves and Cox regression analysis including potential confounders. Overall, 56 patients died over a cumulative follow-up time of 335 months, with an estimated incidence rate of 16.7/100 person-year (PY). The corresponding figures in patients with normal renal function, concealed CKD, and overt CKD were 9.8/100 PY (95% CI, 5.7-15.7), 28.3/100 PY (95% CI, 13.6-52.1), and 23.0 (95% CI, 15.4-33.0), respectively (log rank test p = 0.006). According to the fully adjusted model, both concealed (hazard ratio [HR], 2.35; 95% CI, 1.09-6.01) and overt CKD (HR, 2.09; 95% CI, 1.05-5.34) were significantly associated with the outcome. Concealed CKD contributes to profile the elderly patient at greater risk of death after being discharged from acute care medical wards. If confirmed in broader populations, this finding might have both clinical and epidemiological implications.

Cardiovascular disease in end-stage renal disease: the challenge of assessing and managing cardiac disease in dialysis patients

Cardiovascular disease (CVD) is the leading cause of mortality in end-stage renal disease (ESRD), approximating a 10- to 20-fold higher risk of death in dialysis patients than in the general population. Despite this, dialysis patients often undergo fewer investigations, receive less invasive procedures, and are prescribed fewer medications compared with age-matched non-ESRD patients. A lack of randomized control trials for evidence-based treatment strategies in this population may explain some of these discrepancies, but there is concern that an attitude of "therapeutic nihilism" may be impacting on the medical care of these patients. In this review, we will explore CVD in the ESRD population. Specifically, we will try to address the following issues in patients with ESRD: (1) mechanisms of CVD, (2) cardiac evaluation and the role of coronary revascularization with percutaneous or coronary artery bypass procedures, and (3) cardiac pharmacotherapy use.

Relationship between kidney function and liver histology in subjects with nonalcoholic steatohepatitis

BACKGROUND AND OBJECTIVES

We assessed whether nonalcoholic steatohepatitis (NASH) diagnosed by liver biopsy is associated with decreased kidney function and whether such association is independent of insulin resistance and features of the metabolic syndrome.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

We enrolled 80 consecutive overweight patients with biopsy-proven NASH and 80 nonsteatotic control subjects who were matched for age, gender, and body mass index. Chronic kidney disease (CKD) was defined as the presence of estimated GFR (eGFR) of ≤60 ml/min per 1.73 m(2) and/or abnormal albuminuria (i.e., urinary albumin/creatinine ratio ≥30 mg/g).

RESULTS

NASH patients had significantly (P < 0.001) lower eGFR (75.3 ± 12 versus 87.5 ± 6 ml/min per 1.73 m(2)) and a greater frequency of abnormal albuminuria (14 versus 2.5%) and CKD (25 versus 3.7%) than control subjects. The significant differences in eGFR, albuminuria, and CKD that were observed between the two groups were only slightly weakened after adjustment for age, gender, body mass index, smoking status, insulin resistance (by homeostasis model assessment), and components of the metabolic syndrome. Notably, histologic severity of NASH (i.e., fibrosis stage) was strongly associated with either decreasing eGFR or increasing albuminuria (P < 0.01 or less), independently of potential confounding factors.

CONCLUSIONS

Our findings suggest that patients with biopsy-proven NASH have moderately decreased eGFR and a higher frequency of abnormal albuminuria and CKD than matched control subjects and that the severity of NASH histology is associated with decreased kidney function, independently of traditional risk factors, insulin resistance, and components of the metabolic syndrome.

Strategies for improving long-term survival in peritoneal dialysis patients

The incidence and prevalence of ESRD in the United States continues to increase. Currently there are over 26,000 patients maintained on peritoneal dialysis. Mortality rates have fallen over the past several years, but long-term survival remains poor, with only 11% of peritoneal dialysis patients surviving past 10 years. Cardiovascular disease accounts for most deaths, and dialysis patients have many traditional and nontraditional cardiovascular risk factors. Lowering of these risk factors has not resulted in reduced cardiovascular morbidity and mortality in dialysis patients. Maneuvers to improve long-term peritoneal dialysis patient survival must therefore focus on modifiable risk factors including residual renal function, peritoneal membrane integrity, rate of infections, and peritoneal dialysis center size. This article reviews strategies for preserving residual renal function and peritoneal membrane integrity as well as strategies for reducing the rate of infections to enhance long-term survival in peritoneal dialysis patients.

Acute kidney injury induced by protein-overload nephropathy down-regulates gene expression of hepatic cerebroside sulfotransferase in mice, resulting in reduction of liver and serum sulfatides

Sulfatides, possible antithrombotic factors belonging to sphingoglycolipids, are widely distributed in mammalian tissues and serum. We recently found that the level of serum sulfatides was significantly lower in hemodialysis patients than that in normal subjects, and that the serum level closely correlated to the incidence of cardiovascular disease. These findings suggest a relationship between the level of serum sulfatides and kidney function; however, the molecular mechanism underlying this relationship remains unclear. In the present study, the influence of kidney dysfunction on the metabolism of sulfatides was examined using an established murine model of acute kidney injury, protein-overload nephropathy in mice. Protein-overload treatment caused severe proximal tubular injuries within 4days, and this treatment obviously decreased both serum and hepatic sulfatide levels. The sphingoid composition of serum sulfatides was very similar to that of hepatic ones at each time point, suggesting that the serum sulfatide level is dependent on the hepatic secretory ability of sulfatides. The treatment also decreased hepatic expression of cerebroside sulfotransferase (CST), a key enzyme in sulfatide metabolism, while it scarcely influenced the expression of the other sulfatide-metabolizing enzymes, including arylsulfatase A, ceramide galactosyltransferase, and galactosylceramidase. Pro-inflammatory responses were not detected in the liver of these mice; however, potential oxidative stress was increased. These results suggest that down-regulation of hepatic CST expression, probably affected by oxidative stress from kidney injury, causes reduction in liver and serum sulfatide levels. This novel mechanism, indicating the crosstalk between kidney injury and specific liver function, may prove useful for helping to understand the situation where human hemodialysis patients have low levels of serum sulfatides.

Should diuretics always be included as initial antihypertensive management in early-stage CKD?

PURPOSE OF REVIEW

This review focuses on the need for combined antihypertensive therapy drugs in patients with chronic kidney disease and the relevance of diuretics.

RECENT FINDINGS

Chronic kidney disease is a high-risk situation characterized by the presence of volume overload-related hypertension, micro/macroalbuminuria and other traditional and nontraditional risk factors. To achieve the blood pressure goal in these patients, combined antihypertensive therapy (including diuretics) is usually required.

SUMMARY

Extracellular volume expansion is an important, if not the most important, contributing factor to hypertension seen in chronic kidney disease. Protection against progression of renal dysfunction has two main requirements: strict blood pressure control and lowering proteinuria to values as near to normal as possible. Diuretics have been a useful tool to manage volume overload and to achieve strict blood pressure control in patients with chronic kidney disease. Albeit other blood pressure-lowering agents offer additional favorable effects independently of blood pressure changes, diuretics will continue to be used in these patients.

Cardiorenal syndrome

Kidney dysfunction in patients with heart failure and cardiovascular disorders in patients with chronic kidney disease are common. A recently proposed consensus definition of cardiorenal syndrome stresses the bidirectional nature of these heart-kidney interactions. The treatment of cardiorenal syndrome is challenging, however, promising new therapeutic options are currently being investigated in recent and ongoing clinical trials.

Mechanisms for increased cardiovascular disease in chronic kidney dysfunction

PURPOSE OF REVIEW

Patients with chronic kidney disease (CKD) have the highest risk for atherosclerotic cardiovascular disease (CVD). Current interventions have been insufficiently effective in lessening excess incidence and mortality from CVD in patients with CKD versus other high-risk groups. This review focuses on traditional and CKD-related risks as well as key mechanisms of macrophage foam cell formation that underlie the excess CVD in the setting of CKD.

RECENT FINDINGS

Hyperlipidemia, particularly increased low-density lipoprotein (LDL) cholesterol, is the key factor in atherogenesis in the general population, but has not been found to be the overriding risk for greater CVD in CKD, especially as renal damage progresses. Although higher incidence of CVD in CKD is not due to higher serum lipids per se, CKD is associated with abnormal lipid metabolism that is proatherogenic. CKD-related risks, including inflammation and disturbances in mineral metabolism, have been implicated. In addition, perturbations of the macrophage, a cell that is central in atherogenesis, may be important.

SUMMARY

The mechanisms underlying the heightened risk for CVD in CKD have been the focus of intense study and may relate to the combined effects of traditional and CKD-specific risks involving inflammation and lipid metabolism, especially perturbation of macrophage cholesterol homeostasis.