Comparison of first, second, and third versus the average of six probe-corneal touches for intraocular measurement of two rebound tonometers in healthy horses

The aim of this study was to evaluate the intraocular pressure (IOP) measurements obtained from first, second, and third probe-cornea touch (PCT) and compare them with the average of six PCTs using two rebound tonometers in horses. This study enrolled a total of thirty-eight stallions, comprising of 24 Arabian horses and 14 cross-breeds (with an average age of 8 ± 3 years). The IOP measurements of first, second, and third, as well as the average of six PCTs were obtained using either Tonovet (TV) or Tonovet Plus (TV+) rebound tonometers. The mean differences (95% limits of agreement) between the average of six PCTs and the first, second, and third PCTs were 0.1 (-4.8 to 5), 0.2 (-4.8 to 4.5), and 0.2 (-3.6 to 4.0) mmHg with TV, respectively. With TV+, the differences were 0.3 (-6.6 to 7.2), 1.1 (-8.6 to 10.8), and -0.2 (-3.6 to 4.0) mmHg, respectively. Compared to the average of six PCTs, only 89.5%, 92.1%, and 97.4% of IOP measurements obtained from TV and 78.9%, 73.3%, and 65.8% of IOP measurements obtained from TV+ were within 4 mmHg of the average of six PCTs for first, second, and third PCTs, respectively. In conclusion, the measurement of IOP in the first PCT achieved best agreement with the IOP measurement of six average PCTs. Therefore, the first PCT could be considered as an alternative option for measuring IOP in horses when obtaining an average of six PCTs is not feasible.

Thiol/disulfide homeostasis as a new oxidative stress marker in patients with Fabry disease

This is the first study to show both dynamic thiol-disulfide balance and oxidative stress levels in patients with Fabry disease (FD). This prospective study consists of 30 FD patients and 30 healthy controls. Thiol and disulfide values of the study groups were evaluated using a new, cost-effective and fully automatic colorimetric method. A total of 60 subjects were included in the study. A statistically significant difference was found between the patient and control groups for native and total thiol levels (p < 0.001). In addition, disulfide levels were significantly higher in FD patients compared with the control group (p < 0.003). Native thiol levels showed significantly negative correlation with lysosomal globotriaosylceramide, total oxidant status (TOS), and oxidative stress index (OSI) levels. In addition, a positive correlation was found between disulfide/natural thiol and disulfide/total thiol ratios and TOS, OSI, and blood urea nitrogen. We found total antioxidant status levels were lower in the patient group compared to the control group, while TOS and OSI levels were higher and were statistically significant. This study highlights for the first time a novel, cost-effective and fully automated measurement of thiol-disulfide levels in patients with FD. Determination of thiol levels can make important contributions to understand the etiopathogenesis and follow-up of the disease in FD patients.

Comparison of intraocular pressure in New Zealand White rabbits measured using rebound and applanation tonometers and four different methods of physical restraint

AIMS

To compare intraocular pressure (IOP) measurements obtained in rabbits using rebound (TV) and applanation (TPV) tonometers with four different methods of physical restraint.

METHODS

A total of 20 New Zealand White rabbits (40 eyes) were included in this study. IOP readings were obtained from both eyes using the two different tonometers. The rabbits were placed on a table and restrained by wrapping in a cloth (Method I), by scruffing with rear support (Method II), by wrapping in a cloth and cupped in the hands (Method III), or by a box restrainer (Method IV).

RESULTS

The mean IOP measurement obtained by TPV was higher than that obtained with the TV for all handling methods. Mean differences (TV-TPV, in mmHg) in IOP were -5.3 (95% Cl = -6.5 to -4.1) for Method 1, -4.7 (95% Cl = -6.2 to -3.29) for Method II, -4.9 (95% Cl = -6.2 to -3.7) for Method III and -7.6 (95% Cl = -9.2 to -5.9) for Method IV. Using the TV tonometer, mean IOP for Method IV was higher than for Method I (mean difference 2.1 (95% Cl = 1.1-3.1)), whereas using the TPV tonometer, mean IOP for Method IV was significantly higher than Method I, II, and III (mean differences: 4.4 (95% Cl = 2.6-5.9), 3.7 (95% Cl = 2-5.3) and 3.8 (95% Cl = 2-5.4), respectively). According to Bland-Altman plots, IOP readings for TPV tended to be higher than those for TV with all handling methods, but with a lack of agreement. The mean difference and 95% limits of agreement for the differences between TV and TPV were -5.4 mmHg (-12.5-1.9 mmHg), -4.7 mmHg (-12.9-3.5 mmHg), -4.9 mmHg (-12-2.2 mmHg), and -7.5 mmHg (-17.4-2.3 mmHg), with Methods I, II, III, and IV, respectively. Comparing TV and TPV, only 7.5%, 12.5%, 27.5%, and 15% of IOP measurements from 20 rabbits were within the range considered clinically acceptable for IOP (± 2 mmHg) for Method I, II, III, and IV, respectively.

CONCLUSION AND CLINICAL RELEVANCE

In conclusion, the physical restraint method should be recorded when IOP is measured in rabbits, and TV and TPV tonometers cannot be used interchangeably (high bias and low proportion of measurements within ± 2 mmHg).

Acute Kidney Injury: Medical Causes and Pathogenesis

Acute kidney injury (AKI) is a common clinical syndrome characterized by a sudden decline in or loss of kidney function. AKI is not only associated with substantial morbidity and mortality but also with increased risk of chronic kidney disease (CKD). AKI is classically defined and staged based on serum creatinine concentration and urine output rates. The etiology of AKI is conceptually classified into three general categories: prerenal, intrarenal, and postrenal. Although this classification may be useful for establishing a differential diagnosis, AKI has mostly multifactorial, and pathophysiologic features that can be divided into different categories. Acute tubular necrosis, caused by either ischemia or nephrotoxicity, is common in the setting of AKI. The timely and accurate identification of AKI and a better understanding of the pathophysiological mechanisms that cause kidney dysfunction are essential. In this review, we consider various medical causes of AKI and summarize the most recent updates in the pathogenesis of AKI.

Corneal endothelial cell density and microvascular changes of retina and optic disc in autosomal dominant polycystic kidney disease

Purpose:

Vascular endothelial dysfunction in autosomal dominant polycystic kidney disease (ADPKD) may affect the retinal vascular parameters due to structural similarities of kidney and retina. We aimed to evaluate the microvascular changes of retina and optic disc and also corneal endothelial cell density in patients with ADPKD.

Methods:

Forty-six eyes of 23 patients with ADPKD (Group 1), and 46 eyes of 23 sex- and age-matched healthy controls (Group 2) were included in this cross-sectional study. Demographic and ophthalmic findings of participants were collected. Corneal endothelial cell density (CECD) measurements were obtained by noncontact specular microscopy. Foveal retinal thickness, peripapillary retinal nerve fiber layer (RNFL) thickness, vessel density in different sections of the retina and optic nerve head were analyzed by optical coherence tomography angiography.

Results:

The mean ages were 41 ± 11 years for Group 1 and 39 ± 10 years for Group 2 (P = 0.313). CECD values were significantly lower in group 1 when compared to group 2 (2653 ± 306 cells/mm² and 2864 ± 244 cells/mm², respectively, P < 0.001). The foveal retinal thickness and RNFL thickness were similar, but superior quadrant thickness of RNFL was significantly lower in Group 1 than Group 2 (126 ± 14 μm vs. 135 ± 15 μm, P = 0.003). In Group 1, whole image of optic disc radial peripapillary capillary densities were significantly lower compared to Group 2 (49.4 ± 2.04%, and 50.0 ± 2.2%, respectively, P = 0.043). There was no significant difference regarding superficial, deep retinal vessel densities, foveal avascular zone and flow areas between the groups (P > 0.05 for all).

Conclusion:

Lower CECD values and decreased superior quadrant RNFL thickness, and microvascular densities of optic disc were revealed in patients with ADPKD. Evaluation of CECD and retinal microvasculature may be helpful in the management of these patients.

Determinants of Outcomes of Acute Kidney Injury: Clinical Predictors and Beyond

Acute kidney injury (AKI) is a common clinical syndrome characterized by rapid impairment of kidney function. The incidence of AKI and its severe form AKI requiring dialysis (AKI-D) has been increasing over the years. AKI etiology may be multifactorial and is substantially associated with increased morbidity and mortality. The outcome of AKI-D can vary from partial or complete recovery to transitioning to chronic kidney disease, end stage kidney disease, or even death. Predicting outcomes of patients with AKI is crucial as it may allow clinicians to guide policy regarding adequate management of this problem and offer the best long-term options to their patients in advance. In this manuscript, we will review the current evidence regarding the determinants of AKI outcomes, focusing on AKI-D.

Serum BNP Concentration and Left Ventricular Mass in CAPD and Automated Peritoneal Dialysis Patients

Objective

To compare ultrafiltration under continuous ambulatory peritoneal dialysis (CAPD) and automated PD (APD), disclosing potential effects on serum B-type natriuretic peptide (BNP) levels and echocardiographic findings.

Patients and Methods

This cross-sectional clinical study included 32 patients on CAPD and 30 patients on APD without clinical evidence of heart failure or hemodynamically significant valvular heart disease. Peritoneal equilibration tests, BNP levels, and echocardiographic measurements were performed in each subject. BNP measurements were also performed in 24 healthy control subjects.

Results

Patients on APD had lower ultrafiltration and higher values of BNP and left ventricular mass index (LVMI) compared with patients on CAPD (respectively: 775 ± 160 vs 850 ± 265 mL, p = 0.01; 253.23 ± 81.64 vs 109.42 ± 25.63 pg/mL, p = 0.001; 185.12 ± 63.50 vs 129.30 ± 40.95 g/m2, p = 0.001). This occurred despite higher mean dialysate glucose concentrations and far more extensive use of icodextrin in the APD group.

Conclusion

Treatment with APD is associated with higher plasma BNP levels and LVMI compared to CAPD. This may be the result of chronic fluid retention caused by lower ultra-filtration in APD patients.

Retinal Microcirculation in Predicting Diabetic Nephropathy in Type 2 Diabetic Patients without Retinopathy

PURPOSE

To evaluate retinal thicknesses and retinal microcirculation in healthy controls and in diabetic patients with or without microalbuminuria.

METHODS

Eighty-six diabetic patients without diabetic retinopathy (DR) (44 normoalbuminuric, 42 microalbuminuric) and 51 healthy controls were enrolled in this cross-sectional, prospective study. Optical coherence tomography (OCT) and OCT angiography (OCTA) were performed. Correlations between OCTA parameters with mean urinary albumin levels were evaluated.

RESULTS

The mean vessel densities of superficial capillary plexus (SCP), whole disc, and peripapillary area were significantly decreased in patients with microalbuminuria compared to patients with normoalbuminuria and controls (p < 0.05 for all). The mean vessel density of deep capillary plexus was significantly reduced in patients with microalbuminuria compared to controls (p < 0.05 for all). There were no significant differences in retinal thickness between groups (p > 0.05). Both duration of diabetes and urinary albumin levels were significantly and moderately correlated with mean vessel density of whole SCP in diabetic patients (r = 0.330, p = 0.021; r = 0.356, p = 0.017, respectively).

CONCLUSION

Diabetic eyes without clinically detectable DR show impaired retinal microcirculation. Microalbuminuria is associated with alterations of retinal microcirculation in diabetic patients without DR. Evaluation of retinal microcirculation is likely useful for detecting early changes related to microvascular complications in type 2 diabetic patients.

The association between methylation levels of targeted genes and albuminuria in patients with early diabetic kidney disease

Objective: The incidence of diabetes and its complications are greatly increasing world-wide. Diabeticnephropathy (DN) is the main cause of end-stage renal disease and is associated with high morbidity and mortality. It is important to predict patients with high risk for DN in the early stage. We selected the genes which have an important role on diabetic kidney disease. We aimed to investigate the association between DNA methylation levels of targeted genes and albuminuria in patients with early DN.

Methods: We collected the clinical data of patients with type 2 diabetes mellitus. We measured spot urine albumin creatinine ratio to calculate albuminuria level. We divided patients into two groups based on albumin excretion as patients with (n = 69) and without DN (n = 27). We performed methylation profiling after bisulfite conversion by pyrosequencing method. The mean value of percent methylation level of each gene was calculated.

Results: We compared targeted genes (TIMP-2, AKR1B1, MMP-2, MMP-9, MYL9, SCL2A4, SCL2A1, SCL4A3) methylation levels and albuminuria. We found significant negative correlation between TIMP-2 and AKR1B1 gene methylation levels and albuminuria levels.

Conclusions: The present study provided evidence that hypomethylation of TIMP-2 and AKR1B1 genes can be associated with albuminuria in patients with early DN. We may speculate that the hypomethylation of TIMP-2 and AKR1B1 genes may be an early surrogate marker of DN.

Challenges Associated with Managing End-Stage Renal Disease in Extremely Morbid Obese Patients: Case Series and Literature Review

Obesity has grown into an epidemic across the globe. Mirroring this growth in the number of obese individuals in the general population, the prevalence of obesity and extremely morbid obesity (body mass index >50 kg/m2) is similarly rising in patients with end-stage renal disease (ESRD). Obesity, and more so, extremely morbid obesity, creates additional challenges for clinicians aiming at providing the best treatment options to patients with ESRD. Although literature is available regarding renal replacement therapy (RRT) for obese patients, literature about challenges facing clinicians managing ESRD in the extremely obese patients is lacking. Furthermore, the optimal strategies and goals for managing these patients with ESRD are not well defined. To our knowledge, no study has been done evaluating RRT options available to extremely morbid obese patients and the challenges associated with these options. Here, we report a case series and discuss the potential challenges faced by extremely obese patients with ESRD requiring RRT.

Dialysis Requirement and Long-Term Major Adverse Cardiovascular Events in Patients with Chronic Kidney Disease and Superimposed Acute Kidney Injury

BACKGROUND

Chronic kidney disease (CKD) patients who experience superimposed acute kidney injury (AKI) have been shown to be at higher risk of long-term sequelae of AKI when compared to those who do not experience AKI. It remains unclear whether the need for temporary dialysis intervention following superimposed AKI in patients with CKD has any effect on the long-term major adverse cardiovascular events (MACE). This study examines the relationship between temporary dialysis therapy following AKI and long-term major cardiovascular events in patients with background CKD.

METHODS

The study population consists of adults who developed AKI while on admission at the University of Virginia Medical Center between January 1, 2002 and December 31, 2012, and who had preadmission estimated glomerular filtration rate (eGFR) between 20 and 60 mL/min/1.73 m2 and survived beyond 30 days of AKI. Demographic and baseline clinical variables were used to generate propensity score. Survivors who had temporary dialysis were matched to those managed conservatively according to the propensity score in a ratio of 1:3.

RESULTS

Overall, 6,634 (n = 381 and 6,253 in the temporary dialysis-requiring AKI and non-dialysis AKI groups respectively) met entry criteria for the full cohort. Of these, 381 (5.7%) received temporary dialysis. There were 3,147 (47.4% of all patients) MACE events during the study period. The crude incidence for MACE after 30 days of AKI was similar in both dialyzed and non-dialyzed patients. After the propensity score matching, the adjusted hazard ratio for MACE in dialyzed versus non dialyzed patients was 1.162 (95% CI 0.978-1.381).

CONCLUSIONS

Treatment of AKI with temporary dialysis in hospitalized patients with baseline eGFR between 20 and 60 mL/min/1.73 m2 was not associated with an increased risk for subsequent admission for MACE. If confirmed by prospective studies, clinicians may not need to worry that the dialysis procedure may contribute to additional risk for long-term MACE in CKD patients with superimposed AKI.

The Prevalence of Fabry Disease in Patients with Chronic Kidney Disease in Turkey: The TURKFAB Study

BACKGROUND/AIMS

Fabry disease is a treatable cause of chronic kidney disease (CKD) characterized by a genetic deficiency of α-galactosidase A. European Renal Best Practice (ERBP) recommends screening for Fabry disease in CKD patients. However, this is based on expert opinion and there are no reports of the prevalence of Fabry disease in stage 1-5 CKD. Hence, we investigated the prevalence of Fabry disease in CKD patients not receiving renal replacement therapy.

METHODS

This prospective study assessed α-galactosidase activity in dried blood spots in 313 stage 1-5 CKD patients, 167 males, between ages of 18-70 years whose etiology of CKD was unknown and were not receiving renal replacement therapy. The diagnosis was confirmed by GLA gene mutation analysis.

RESULTS

Three (all males) of 313 CKD patients (0.95%) were diagnosed of Fabry disease, for a prevalence in males of 1.80%. Family screening identified 8 aditional Fabry patients with CKD. Of a total of 11 Fabry patients, 7 were male and started enzyme replacement therapy and 4 were female. The most frequent manifestations in male patients were fatigue (100%), tinnitus, vertigo, acroparesthesia, hypohidrosis, cornea verticillata and angiokeratoma (all 85%), heat intolerance (71%), and abdominal pain (57%). The most frequent manifestations in female patients were fatigue and cornea verticillata (50%), and tinnitus, vertigo and angiokeratoma (25%). Three patients had severe episodic abdominal pain attacks and proteinuria, and were misdiagnosed as familial Mediterranean fever.

CONCLUSIONS

The prevalence of Fabry disease in selected CKD patients is in the range found among renal replacement therapy patients, but the disease is diagnosed at an earlier, treatable stage. These data support the ERBP recommendation to screen for Fabry disease in patients with CKD of unknown origin.

Role of ultrasonographic chronic kidney disease score in the assessment of chronic kidney disease

PURPOSE

Ultrasonography (US) is an inexpensive, noninvasive and easy imaging procedure to comment on the kidney disease. Data are limited about the relation between estimated glomerular filtration rate (e-GFR) and all 3 renal US parameters, including kidney length, parenchymal thickness and parenchymal echogenicity, in chronic kidney disease (CKD). In this study, we aimed to investigate the association between e-GFR and ultrasonographic CKD score calculated via these ultrasonographic parameters.

METHODS

One hundred and twenty patients with stage 1-5 CKD were enrolled in this study. The glomerular filtration rate was estimated by the Chronic Kidney Disease Epidemiology Collaboration equation. US was performed by the same radiologist who was blinded to patients' histories and laboratory results. US parameters including kidney length, parenchymal thickness and parenchymal echogenicity were obtained from both kidneys. All 3 parameters were scored for each kidney, separately. The sum of the average scores of these parameters was used to calculate ultrasonographic CKD score.

RESULTS

The mean age of patients was 63.34 ± 14.19 years. Mean kidney length, parenchymal thickness, ultrasonographic CKD score and median parenchymal echogenicity were found as 96.2 ± 12.3, 10.97 ± 2.59 mm, 6.28 ± 2.52 and 1.0 (0-3.5), respectively. e-GFR was positively correlated with kidney length (r = 0.343, p < 0.001), parenchymal thickness (r = 0.37, p < 0.001) and negatively correlated with CKD score (r = -0.587, p < 0.001) and parenchymal echogenicity (r = -0.683, p < 0.001). Receiver operating characteristic curve analysis for distinction of e-GFR lower than 60 mL/min showed that the ultrasonographic CKD score higher than 4.75 was the best parameter with the sensitivity of 81% and positive predictivity of 92% (AUC, 0.829; 95% CI, 0.74-0.92; p < 0.001).

CONCLUSION

We found correlation between e-GFR and ultrasonographic CKD score via using all ultrasonographic parameters. Also, our study showed that ultrasonographic CKD score can be useful for distinction of CKD stage 3-5 from stage 1 and 2. We suggested that the ultrasonographic CKD score provided more objective data in the assessment of CKD.

Higher Serum Bisphenol A Levels in Diabetic Hemodialysis Patients

BACKGROUND

Bisphenol A (BPA) has been implicated as an 'endocrine disruptor'. We aimed at exploring the association between serum BPA levels and patient characteristics, particularly the presence of diabetes mellitus, and laboratory parameters in hemodialysis patients.

METHODS

This study included 47 chronic hemodialysis patients. Patient characteristics were recorded. Blood was drawn before and after hemodialysis session. Serum BPA levels were measured by the high-performance-liquid-chromatography and laboratory parameters were measured by using standard methods.

RESULTS

In hemodialysis patients, postdialysis serum BPA levels were significantly higher than predialysis after a single hemodialysis session (5.57 ± 1.2 vs. 4.06 ± 0.73, p < 0.0001). Predialysis serum BPA levels were significantly higher in patients with diabetes than non-diabetics (4.4 ± 0.6 vs. 3.9 ± 0.7, p = 0.025). No association was found between serum BPA levels and patient characteristics, and particularly laboratory parameters.

CONCLUSION

Serum BPA levels were rising significantly after a single dialysis session. Diabetic hemodialysis patients had higher predialysis serum BPA levels.

Management of hypertension: Current state of the art and challenges

Hypertension is a major modifiable cardiovascular risk factor. Hypertension is also recognized as the most important risk factor for global disease burden. It is well established that a sustained reduction in blood pressure by drugs reduces the incidence of cardiovascular morbidity and mortality. In recent years, studies and new guidelines published for the management of hypertension. Awareness, treatment and control of hypertension are very poor, despite the new guidelines. We highlighted the management of hypertension in the light of current literature.

Hypertension in the elderly: unique challenges and management

Elderly individuals, worldwide, are on the rise, posing new challenges to care providers. Hypertension is highly prevalent in elderly individuals, and multiple challenges face care providers while managing it. In addition to treating hypertension, the physician must treat other modifiable cardiovascular risk factors in patients with or without diabetes mellitus or chronic kidney disease to reduce cardiovascular events and mortality. This review discusses some of the unique characteristics of high blood pressure in the elderly and provides an overview of the challenges facing care providers, as well as the current recommendations for management of hypertension in the elderly.

Serum gamma-glutamyltransferase levels are inversely related to endothelial function in chronic kidney disease

BACKGROUNDS

Gamma-glutamyltransferase (GGT) is an enzyme responsible for the extracellular catabolism of the antioxidant glutathione and recently implicated in the pathogenesis of atherosclerosis. Endothelial dysfunction is a prodromal feature of atherogenesis. Since oxidative stress is highly present in uremia and causally linked to endothelial dysfunction, we hypothesized that GGT may be a factor implicated in this process.

METHODS

Serum GGT and C-reactive protein (CRP) levels, estimated glomerular filtration rate (eGFR), and 24-h proteinuria were measured in 214 nondiabetic stages 3-5 CKD patients. The endothelium-dependent vasodilatation (FMD) of the brachial artery was assessed by using high-resolution ultrasound. We investigated the relationship between FMD and circulating serum GGT.

RESULTS

Serum GGT levels were negatively associated with FMD (r = -0.41, p < 0.001) and eGFR (r = -0.34, p < 0.001) in univariate analysis. Multivariate regression analysis showed that the association between GGT and FMD persisted after adjustment for age, sex, smoking, renal function (eGFR), inflammation (CRP), proteinuria, and homeostatic model assessment index.

CONCLUSION

Circulating GGT levels significantly associate with endothelial dysfunction, an important early feature of the atherogenic process. GGT might be an early marker of oxidative or other cellular stress that it is possibly directly related to the pathogenesis of endothelial dysfunction.

Sleep quality, depression, and quality of life in elderly hemodialysis patients

OBJECTIVE

Both the incidence and the prevalence of end-stage renal disease (ESRD) in elderly patients are increasing worldwide. Elderly ESRD patients have been found to be more prone to depression than the general population. There are many studies that have addressed the relationship between sleep quality (SQ), depression, and health related quality of life (HRQoL) in ESRD patients, but previous studies have not confirmed the association in elderly hemodialysis (HD) patients. Therefore, the aim of the present study was to demonstrate this relationship in elderly HD patients.

PATIENTS AND METHODS

Sixty-three elderly HD patients (32 females and 31 males aged between 65 and 89 years) were included in this cross-sectional study. A modified Post-Sleep Inventory (PSI), the Medical Outcomes Study 36-item short form health survey, and the Beck Depression Inventory (BDI) were applied.

RESULTS

The prevalence of poor sleepers (those with a PSI total sleep score [PSI-4 score] of 4 or higher) was 71% (45/63), and the prevalence of depression was 25% (16/63). Of the 45 poor sleepers, 15 had depression, defined as a BDI score of 17 or higher. Poor sleepers had a significantly higher rate of diabetes mellitus (P = 0.03), significantly higher total BDI scores, and lower Physical Component Scale scores (ie, lower HRQoL) than good sleepers. The PSI-4 score correlated negatively with Physical Component Scale (r = -0.500, P < 0.001) and Mental Component Scale scores (r = -0.527, P < 0.001) and it correlated positively with the BDI score (r = 0.606, P < 0.001). In multivariate analysis, independent variables of PSI-4 score were BDI score (beta value [β] = 0.350, P < 0.001), Mental Component Scale score (β = -0.291, P < 0.001), and age (β = 0.114, P = 0.035).

CONCLUSION

Poor SQ is a very common issue and is associated with both depression and lower HRQoL in elderly HD patients.

Falls in elderly hemodialysis patients

The elderly, (age ≥ 65 years) hemodialysis (HD) patient population is growing rapidly across the world. The risk of accidental falls is very high in this patient population due to multiple factors which include aging, underlying renal disease and adverse events associated with HD treatments. Falls, the most common cause of fatal injury among elderly, not only increase morbidity and mortality, but also increase costs to the health system. Prediction of falls and interventions to prevent or minimize fall risk and associated complications will be a major step in helping these patients as well as decreasing financial and social burdens. Thus, it is vital to learn how to approach this important problem. In this review, we will summarize the epidemiology, risk factors, pathophysiology and complications of falls in elderly HD patients. We will also focus on available methods to assess and predict the patients at higher risk of falling and will provide recommendations for interventions to reduce the occurrence of falls in this population.

Serum uric acid level and endothelial dysfunction in patients with nondiabetic chronic kidney disease

BACKGROUND

An elevated serum uric acid level is strongly associated with endothelial dysfunction and inflammation, both of which are common in chronic kidney disease (CKD). We hypothesized that endothelial dysfunction in subjects with CKD would correlate with uric acid levels.

MATERIALS AND METHODS

We evaluated the association between serum uric acid level and ultrasonographic flow-mediated dilatation (FMD) in 263 of 486 patients with recently diagnosed CKD (stage 3-5) (48% male, age 52 ± 12 years). To minimize confounding, 233 patients were excluded because they were diabetic, had established cardiovascular complications or were taking drugs (renin-angiotensin system blockers, statins) interfering with vascular function.

RESULTS

Serum uric acid level was significantly increased in all stages of CKD and strongly correlated with estimated glomerular filtration rate (eGFR-MDRD); FMD was inversely associated with serum uric acid (r = -0.49, p < 0.001). The association of serum uric acid with FMD remained after adjustment for age, gender, smoking, LDL cholesterol, eGFR, high-sensitivity C-reactive protein, systolic blood pressure, proteinuria, and homeostatic model assessment index (β = -0.27, p < 0.001).

CONCLUSION

Increased serum uric acid is an independent predictor of endothelial dysfunction in subjects with CKD.

Long-term morbidity and mortality related to falls in hemodialysis patients: role of age and gender - a pilot study

BACKGROUND

Patients with end-stage renal disease (ESRD) on hemodialysis (HD) are prone to falls. In this pilot study, we aimed to determine the incidence of falls in a cohort of HD patients during a 1-year period, to identify any specific risk factors that may predict falls in this cohort, and to assess whether falls can independently predict hospitalization, nursing home admissions and/or mortality over an additional 2 years.

MATERIALS AND METHODS

Baseline assessments followed by documentation of falls prospectively during a 1-year period were done on 76 HD patients. Patients were followed for an additional 2 years and four outcomes were recorded: all-cause death, nursing home admission, the number and duration of all hospitalizations.

RESULTS

20 patients (26.3%) fell over a 12-month period. Elderly and females had a higher risk of falls than the younger and male population (p = 0.034 and 0.006 respectively). During the 2-year follow-up, compared to non-fallers, fallers had a 2.13-fold increase in risk of death, a 3.5-fold increase in risk of nursing home admission, and nearly a 2-fold increase in the number and duration of hospitalizations.

CONCLUSIONS

Falls are common in HD patients, with a higher incidence in females and elderly, and are associated with worse outcomes, more so in recurrent fallers.

Screening for depression in elderly hemodialysis patients

BACKGROUND

Depression is common and associated with increased morbidity and mortality in elderly (≥65 years) hemodialysis patients. Beck's Depression Inventory (BDI) and the Geriatric Depression Scale (GDS) have been used in different cohorts to screen for depression.

OBJECTIVES

We aimed to evaluate the 15-item GDS (GDS-15) as such a tool in elderly hemodialysis patients and compare it with BDI, a previously validated tool in younger hemodialysis patients.

DESIGN

Cross-sectional study.

SETTING

Four out-patient hemodialysis units; 1 based in a university hospital and 3 based in the community.

PARTICIPANTS

Hemodialysis patients aged 65 years and older.

INTERVENTION

Both tools were administered to all participants, and a geriatric psychiatrist blinded to the results evaluated them for depression by the gold standard psychiatric interview.

MEASUREMENTS

The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for both tools were assessed against the psychiatric interview (n = 62).

RESULTS

Patients who were depressed according to the psychiatric interview had significantly higher GDS-15 and BDI scores compared to those not depressed (p < 0.01 both). ROC curves showed high predictive accuracy of the GDS-15 and BDI (area under the curve: 0.808 and 0.729) versus the psychiatric interview. The GDS-15 cutoff with the best diagnostic accuracy was 5 with a sensitivity of 63%, specificity of 82%, PPV of 60% and NPV of 83%. The BDI cutoff with the best diagnostic accuracy was 10 with a sensitivity of 68%, specificity of 77%, PPV of 57% and NPV of 85%.

CONCLUSION

These results provide evidence that the GDS-15 shows validity in comparison to a gold standard and can be used to screen for depression in the elderly hemodialysis population.

Potential new therapeutic agents for diabetic kidney disease

Diabetic nephropathy is the leading cause of end-stage renal disease, and both the incidence and prevalence of diabetic nephropathy continue to increase. Currently, various treatment regimens and combinations of therapies provide only partial renoprotection. It is obvious that new approaches are desperately needed to retard the progression of diabetic nephropathy. Recently, a number of new agents have been described that have the potential to delay the progression of diabetic kidney disease and minimize the growing burden of end-stage renal disease. These include inhibitors and breakers of advanced glycation end products, receptor antagonists for advanced glycation end products, protein kinase C inhibitors, NADPH (reduced nicotinamide adenine dinucleotide phosphate) oxidase inhibitors, glycosaminoglycans, endothelin receptor antagonists, antifibrotic agents, and growth factor inhibitors. This review addresses these promising new therapeutic agents for delaying the progression of diabetic kidney disease.

Renin-angiotensin-aldosterone system blockade effects on the kidney in the elderly: benefits and limitations

The proportion of the population that is elderly (age>or=65 years) is growing across the world. The increasing longevity of humans results in a higher number of elderly patients' presenting with multiple chronic diseases such as hypertension, diabetes, and chronic kidney disease (CKD). These problems increase morbidity and mortality in the elderly. Overactivity of the renin-angiotensin-aldosterone system (RAAS) is associated with the development of hypertension, cardiovascular events, and CKD, so targeting the RAAS is a logical therapeutic approach. Elderly patients present special concerns regarding the benefits versus risks of using RAAS blockers. Plasma renin activity declines with age, which has been attributed to the effect of age-associated nephrosclerosis. Plasma aldosterone is also reduced with age, resulting in a greater risk for hyperkalemia in older individuals, especially when coupled with the age-associated decline in GFR. Moreover, the elderly have a higher frequency of concurrent conditions and are on many medications, which may further increase the risk for adverse effects of RAAS blocking agents. Unfortunately, there is a paucity of literature that is specifically aimed at studying elderly using the RAAS blockers. We present in our in-depth review data regarding benefits and limitations of the use of the RAAS blockades on the various sites along the RAAS pathway for elderly patients. Specific attention was given to the role of combination RAAS blockade therapy and higher monotherapy dosing in the treatment of hypertension in the elderly.

Magnesium in Chronic Kidney Disease: Challenges and Opportunities

Cardiovascular disease is the leading cause of mortality and morbidity in patients with chronic kidney disease, which is partly explained by the fact that 40–70% of patients receiving dialysis have significant coronary artery disease. Recent clinical studies have shown that lower serum magnesium (Mg) levels are associated with vascular calcification and cardiovascular mortality among patients with end-stage renal disease (ESRD). On the other hand, hypermagnesemia inhibits parathyroid hormone secretion, which is considered an important independent risk factor for vascular calcification, left ventricular hypertrophy and mortality in ESRD patients. Finally, increasing evidence points towards a link between Mg and cardiovascular disease, even in subjects without chronic kidney disease. The purpose of this review was to critically review the current literature examining the effects of plasma Mg levels on cardiovascular disease and parathyroid hormone homeostasis in ESRD, and renal transplant patients.

Statin treatment for dyslipidemia in chronic kidney disease and renal transplantation: a review of the evidence

Patients with chronic kidney disease (CKD) have significantly increased risks of cardiovascular (CV) morbidity and mortality. Dyslipidemia is a common disorder in CKD patients. CKD patients have a different lipid profile with increased atherogenic lipid fractions, and serum low-density lipoprotein cholesterol (LDL-C) levels may underestimate the atherogenic effect of LDL-C in these patients. Dyslipidemia may contribute to the increased CV morbidity and mortality, and to the progression of kidney disease in CKD patients. Currently, statins are the pharmacologic intervention of first choice, if lifestyle changes fail adequately to lower LDL-C levels in the setting of normal or moderately elevated triglycerides. Statins have been extensively studied in a large variety of patient populations and have proven efficacy in the treatment of dyslipidemia, and in reducing CV mortality. Although much evidence supports the CV benefits of statins in patients with normal renal function, there are contradictory results for the beneficial effect of statin therapy on CV morbidity and mortality in CKD patients. While post hoc subgroup analyses of multiple randomized trials support statin use in early CKD patients, the only randomized trial conducted in diabetic dialysis patients found no evidence of benefit in overall mortality. Post transplant there is some definite CV benefit, albeit in a patient cohort selected to be at reduced CV risk by virtue of being eligible for organ transplant. The results from the AURORA and SHARP studies are awaited anxiously.

Circadian rhythm of blood pressure in patients with benign prostatic hyperplasia

OBJECTIVE

Nocturia, a common and bothersome symptom of benign prostatic hyperplasia (BPH), may cause sleep disturbances. Patients with nocturia may have difficulty returning to their normal sleep after repeated episodes of waking and voiding. Therefore, nocturia may have an impact on the circadian rhythm of blood pressure (BP). The association between nocturia and the circadian rhythm of BP was investigated in this study.

MATERIAL AND METHODS

A total of 100 male patients who had been diagnosed with BPH and 53 healthy male subjects were included in the study. Nocturnal urinary frequency was assessed by means of a questionnaire and recorded in both groups. Ambulatory BP monitoring was performed in all patients over a 24-h period.

RESULTS

Patient characteristics and laboratory parameters were similar in both groups. Seventy-five patients (75%) in the BPH group and 20 subjects (37.7%) in the control group were non-dippers, i.e. they did not have a normal nocturnal fall in BP, and this difference was statistically significant (p=0.001). Eighty-nine patients in the BPH group and 13 in the control group had nocturia. Seventy-one patients (79.8%) with nocturia were non-dippers and the difference compared to the patients without nocturia in the BPH group was significant (p=0.003), whereas four patients with nocturia (30.8%) were non-dippers in the control group.

CONCLUSIONS

Our findings indicate that non-dipping was more prevalent in elderly men with BPH and nocturia. BPH and nocturia may be etiological factors in the pathogenesis of non-dipping, which is an indicator of early cardiovascular disease. Further studies must focus on this relationship and, especially, on whether treatment of nocturia and BPH helps to treat non-dipping or not.

Sodium bicarbonate for the prevention of contrast-induced nephropathy: a meta-analysis of 17 randomized trials

BACKGROUND

Contrast-induced nephropathy (CIN) is a common cause of acute kidney injury. Several preventive therapies for this injury have been tested; however, there is still no consensus on the optimal protocol.

METHODS

We performed a systematic search of the National Library of Medicine and the Cochrane Library databases from January 1985 to November 2008 to identify randomized controlled studies examining sodium bicarbonate as a preventive measure for CIN in humans. We also reviewed conference abstracts from cardiology nephrology and radiology meetings from 2004 to 2008. A change in serum creatinine levels defined by an absolute (>or=0.5 mg/dl) or percentage (>or=25%) increase in the serum creatinine level is defined as CIN. The primary outcome measure was the incidence of CIN, and the secondary outcome measures were: change in serum creatinine from baseline, requirement for renal replacement therapy and death.

RESULTS

Seventeen randomized controlled trials have investigated the role of sodium bicarbonate for prophylaxis of CIN. The overall incidence of CIN was 11.3%. Using the results from all 17 studies that compared bicarbonate versus saline, the pooled relative risk of developing CIN was 0.54 (95% CI, 0.36-0.83) in the intervention arm, indicating a significant benefit from sodium bicarbonate. The pooled relative risk of CIN was 0.57 (95% CI, 0.35-0.95) when we analyzed for the studies that compared the effects sodium bicarbonate to NAC on development of CIN. There was no difference in the rates of requirement for renal replacement therapy and death.

CONCLUSIONS

The use of sodium bicarbonate appears to reduce the incidence of CIN when compared to other preventive strategies for CIN without a significant difference in the requirement of renal replacement therapy and mortality. There are study heterogeneity and publication biases. Further adequately powered randomized controlled studies are needed to determine whether sodium bicarbonate will reduce the clinically meaningful outcomes (e.g., need for dialysis or death) and optimal hydration strategy in high-risk patients.

Causes and mechanisms of nondipping hypertension

Growing evidence indicates that nondippers have worsened cardiovascular outcomes than dippers. Ambulatory blood pressure monitoring with a lack of nocturnal BP fall (nondipping) have also been shown to be more closely associated with target organ damage and worsened cardiovascular outcome than in patients with essential hypertension with dipping pattern. The underlying pathogenetic mechanisms potentially linking nondipping with cardiovascular disease are not fully understood. There are multiple possible underlying pathophysiologic mechanisms in the impaired BP decline during the night. Extrinsic and intrinsic factors including abnormal neurohormonal regulation, lack of physical activity, nutritional factors such as increased dietary sodium intake, and smoking of tobacco have been implicated for blunted circadian rhythm of BP. Certain diseases such as diabetes and chronic renal diseases also affect the circadian BP rhythm. Currently, the clinical importance of nondipping is known well; however, the relationship between certain disease states and nondipping has not been fully explained yet. This paper will attempt to address to clarify the underlying basis for nondipping and the specific associations with various disease states.

Antioxidant and protective effects of silymarin on ischemia and reperfusion injury in the kidney tissues of rats

BACKGROUND

Renal ischemia/reperfusion (I/R) injury is a major cause of acute renal failure. Silymarin is extracted from Silybum marianum and Cynara cardunculus seeds and fruits. The aim of this study is to investigate whether silymarin administration prevents the damage induced by I/R in rat kidneys.

MATERIALS AND METHODS

Thirty male Wistar rats were randomly divided into five experimental groups (n = 6, each) as follows; control group, sham-operated group, I/R group, silymarin group, and I/R + silymarin group. In the I/R and I/R + silymarin groups, both renal arteries were occluded using nontraumatic microvascular clamps for 45 min. Then, at the end of 24 h of reperfusion, the animals were killed. Kidney function tests, the serum and tissue antioxidant enzymes and oxidant products were determined.

RESULTS

Animals that were subjected to I/R exhibited significant increase in serum urea, creatinine, and cystatin C levels compared with the rats treated with silymarin prior to the I/R process (P < 0.001). The serum enzymatic activities of superoxide dismutase and glutathione peroxidase significantly decreased in the I/R group; however, this reduction was significantly improved by the treatment with silymarin (P < 0.001 and P < 0.05, respectively). Renal I/R produced a significant increase in serum and tissue malondialdehyde, nitric oxide, and protein carbonyl as compared with controls. Treatment with silymarin resulted in significant reduction in these markers (P < 0.001).

CONCLUSION

Based on our findings, silymarin protects the kidneys against I/R injury. This finding may provide a basis for the development of novel therapeutic strategies for protection against the damages caused by I/R.

Association of obesity with inflammation in occult chronic kidney disease

BACKGROUND

There are few studies concerning the development of chronic kidney disease (CKD) in obese patients independent of its relation with other risk factors. Also, the role of inflammation in this relationship is unclear. In this study we aimed to test the hypothesis that obesity is associated with risk for CKD and whether this risk is associated with serum C-reactive protein (CRP) levels in an apparently healthy obese population.

METHODS

Biochemical parameters and urinary protein excretion were determined in 110 patients with body mass index (BMI) >30.0 (calculated as kg/m2) and 50 age-matched healthy controls. Glomerular filtration rate was estimated by calculation of creatinine clearance.

RESULTS

Of the patients, 17.3% had CKD. They had higher CRP levels than controls (6.52 +/- 0.58 mg/L and 4.48 +/- 1.26 mg/L, respectively, p=0.001). Furthermore, CRP levels were positively correlated with BMI, waist circumference, waist to hip ratio and proteinuria, and negatively correlated with glomerular filtration rate (GFR). When GFR was considered as the dependent variable in a multiple regression analysis, CRP maintained its significant correlation with GFR.

CONCLUSION

Our study of apparently healthy obese individuals, has shown a significant association between BMI and CKD independent of other potential mediators. Furthermore, our findings suggest that inflammation may be the pathogenic mechanism of obesity-related CKD.

Improvement of endothelial dysfunction with simvastatin in patients with autosomal dominant polycystic kidney disease

Cardiovascular problems are a major cause of morbidity and mortality in patients with autosomal dominant polycystic kidney disease (ADPKD). Endothelial dysfunction (ED), which is an early manifestation of vascular injury, has been shown in patients with ADPKD. Statins have a beneficial effect in the reversal of ED. The aim of this study was to investigate the effects of a statin, simvastatin, on ED in patients with ADPKD. Sixteen patients with ADPKD having well-preserved renal function were included in the study. Endothelial function of the brachial artery was evaluated by using high-resolution vascular ultrasound. Endothelial-dependent dilatation (EDD) was expressed as the percentage change in the brachial artery diameter from baseline to reactive hyperemia. After the baseline evaluations of EDDs, patients were started treatment with simvastatin at a dose of 40 mg/day and were treated for six months. EDDs were recalculated after one and six months of therapy. Interleukin-6 (IL-6) and high-sensitivity C-reactive protein were also measured as markers of inflammation. Baseline EDD was 11.3 +/- 6.9% in patients with ADPKD. After one month of simvastatin treatment, EDD increased significantly to 14.6 +/- 4.6 % (P = 0.016 versus baseline). Endothelial-dependent dilatation further increased significantly to 18.9 +/- 7.5 % (P = 0.011 versus baseline, P = 0.048 versus first month) after six months of therapy. There was also a significant decrease in the level of IL-6 from 21.6 +/- 21.7 pg/mL to 9.1 +/- 3.5 pg/mL (P= 0.002). Six months of simvastatin therapy resulted in a significant improvement of ED in patients with ADPKD. This finding may be in part related to the pleiotropic effects of simvastatin.

Ambulatory blood pressure and endothelial dysfunction in patients with autosomal dominant polycystic kidney disease

Cardiovascular problems are a major cause of morbidity and mortality in patients with autosomal dominant polycystic kidney disease (ADPKD). Endothelial dysfunction (ED), which is an early manifestation of vascular injury, has been shown in patients with ADPKD. However, the association between ambulatory blood pressure and ED has not been investigated in these patients. Forty-one patients with ADPKD having well-preserved renal function were included in the study. Ambulatory blood pressure monitoring was performed in all patients. Patients were divided into dipper and non-dipper groups. Endothelial function of the brachial artery was evaluated by using high-resolution vascular ultrasound. Endothelial-dependent dilatation was expressed as the percentage change in the brachial artery diameter from baseline to reactive hyperemia. The mean 24-hour systolic blood pressure was similar in both groups (125.5 +/- 10.7 mmHg in dippers and 121.2 +/- 14.3 in non-dippers, p > 0.05). There was also no significant difference between the mean 24-hour diastolic blood pressures in both groups (82.3 +/- 9.6 mmHg in dippers and 77.1 +/- 8.6 mmHg in non-dippers, p > 0.05). The nocturnal fall rate in systolic blood pressure was 11.1 +/- 1.2% in dippers and 0.98 +/- 0.9% in non-dippers (p = 0.001). The nocturnal fall rate in diastolic blood pressure was 14.0 +/- 0.9% in dippers and 3.8 +/- 0.8% in non-dippers (p = 0.001). Endothelial-dependent dilatation was significantly higher in dippers compared to non-dippers (6.22 +/- 4.14% versus 3.57 +/- 2.52%, p = 0.025). Non-dipper patients with ADPKD show significant ED, which has an important impact on cardiovascular morbidity and mortality.

Membranoproliferative glomerulonephritis associated with pseudoxanthoma elasticum

Pseudoxanthoma elasticum (PXE) is a multiorgan disorder affecting mainly the skin, the eyes, and the cardiovascular system. A 51-year-old woman was admitted to our clinic complaining of weakness and swelling of her legs for the past two years. She had a proteinuria of 7.29 g/24 h. Renal biopsy was performed, and the histological diagnosis was membranoproliferative glomerulonephritis. Four weeks later, she was admitted to the hospital due to pain in her left hand and necrosis in the fourth and fifth fingertips of the left hand. A skin biopsy was performed from the forearm and was reported as PXE. Herein, we present a case of membranoproliferative glomerulonephritis accompanying PXE.

Serum BNP concentration and left ventricular mass in CAPD and automated peritoneal dialysis patients

OBJECTIVE

To compare ultrafiltration under continuous ambulatory peritoneal dialysis (CAPD) and automated PD (APD), disclosing potential effects on serum B-type natriuretic peptide (BNP) levels and echocardiographic findings.

PATIENTS AND METHODS

This cross-sectional clinical study included 32 patients on CAPD and 30 patients on APD without clinical evidence of heart failure or hemodynamically significant valvular heart disease. Peritoneal equilibration tests, BNP levels, and echocardiographic measurements were performed in each subject. BNP measurements were also performed in 24 healthy control subjects.

RESULTS

Patients on APD had lower ultrafiltration and higher values of BNP and left ventricular mass index (LVMI) compared with patients on CAPD (respectively: 775 +/- 160 vs 850 +/- 265 mL, p = 0.01; 253.23 +/- 81.64 vs 109.42 +/- 25.63 pg/mL, p = 0.001; 185.12 +/- 63.50 vs 129.30 +/- 40.95 g/m(2), p = 0.001). This occurred despite higher mean dialysate glucose concentrations and far more extensive use of icodextrin in the APD group.

CONCLUSION

Treatment with APD is associated with higher plasma BNP levels and LVMI compared to CAPD. This may be the result of chronic fluid retention caused by lower ultrafiltration in APD patients.

Probrain natriuretic peptide for assessment of efficacy in heart failure treatment

N-terminal probrain natriuretic peptide (NT-proBNP) is elevated in patients with heart failure. Numerous clinical trials have evaluated the efficacy of spironolactone in heart failure; however, no studies have directly examined the effects of spironolactone treatment on NT-proBNP level. This study investigated whether NT-proBNP levels decrease with daily spironolactone treatment. The study consisted of 117 adult patients with heart failure. All participants were divided into 3 groups, class I, class II, and class III, according to the New York Heart Association classification system. Patients were randomly assigned to receive spironolactone or were treated with another drug, other than spironolactone, as placebo. NT-proBNP plasma samples were taken at baseline and after 6 mo of treatment. A total of 62 patients were treated with daily spironolactone; 55 patients were followed with available treatment without spironolactone. The baseline demographic and laboratory parameters were similar for patients in all groups. At the end of 6 mo, spironolactone-treated patients had significantly lower NT-proBNP levels and significantly better ejection fractions than did patients in all New York Heart Association classes who were not treated with spironolactone. Results suggest that spironolactone decreases plasma NT-proBNP concentrations, and that the measurement of plasma NT-proBNP levels may be helpful in assessing therapeutic efficacy in patients who are treated for heart failure.