Downregulation of AdipoR1 is Associated with increased Circulating Adiponectin Levels in Serbian Chronic Kidney Disease Patients

The impact of uremic toxins on Alzheimer's disease

Alzheimer's disease (AD) is the most common type of dementia, pathologically characterized by accumulation of senile plaques and neurofibrillary tangles. Chronic kidney disease (CKD) is highly prevalent in elderly population closely associated with occurrence of dementia. Recent epidemiological and experimental studies suggest a potential association of CKD with AD. Both diseases share a panel of identical risk factors, such as type 2 diabetes; and hypertension. However, the relationship between CKD and AD is unclear. Lower clearance of a panel of uremic toxin including cystatin-C, guanidine, and adiponectin due to CKD is implied to contribute to AD pathogenesis. In this review we summarize the current evidence from epidemiological, experimental and clinical studies on the potential contribution of uremic toxins to AD pathogenesis. We describe outstanding questions and propose an outlook on the link between uremic toxins and AD.

Adiponectin in Chronic Kidney Disease

Adiponectin is the adipokine associated with insulin sensitization, reducing liver gluconeogenesis, and increasing fatty acid oxidation and glucose uptake. Adiponectin is present in the kidneys, mainly in the arterial endothelium and smooth muscle cells, as well as in the capillary endothelium, and might be considered as a marker of many negative factors in chronic kidney disease. The last few years have brought a rising body of evidence that adiponectin is a multipotential protein with anti-inflammatory, metabolic, anti-atherogenic, and reactive oxygen species (ROS) protective actions. Similarly, adiponectin has shown many positive and direct actions in kidney diseases, and among many kidney cells. Data from large cross-sectional and cohort studies showed a positive correlation between serum adiponectin and mortality in chronic kidney disease. This suggests a complex interaction between local adiponectin action, comorbidities, and uremic milieu. In this review we discuss the role of adiponectin in chronic kidney disease.

Chemerin, Resistin, and Adiponectin in Patients with Connective Tissue Diseases

Background

The exact role of cytokines in inflammation and metabolic disorders in case of connective tissue diseases (CTDs) is under discussion.

Methods

In this study, we intended to find the relationship between the selected cytokines in inflammatory and metabolic disorders in patients with CTDs (n=55) and compared the results with those of control group subjects (n=25) matched by age and body mass. We estimated their nutritional status by the bioimpedance method. The levels of basic biochemical parameters and the levels of adiponectin, resistin, and chemerin were also estimated. Multiple regressions and area under the curve in receiver operating characteristic (AUC-ROC) curve were used to find the associations of aforementioned parameters.

Results

Patients with CTDs exhibited higher levels of chemerin than that of control group subjects. We found an inverse relationship between chemerin, RBC count, and hemoglobin levels. The concentration of adiponectin inversely correlated with the levels of platelets and concentrations of glucose and triglycerides as well as the erythrocyte sedimentation rate, whereas the concentration of resistin was positively correlated with WBC count, C-reactive protein (CRP), and the amount of used oral glucocorticosteroids. The mean ± standard deviation for the AUC-ROC curve in case of chemerin was the highest (AUC-ROC=0.714, p=0.0005) than that of both resistin and adiponectin.

Conclusions

Chemerin and resistin levels are related to the inflammatory state in patients with CTDs, whereas adiponectin levels seem to be correlated with a protective effect. Chemerin can be considered as a marker differentiating a proinflammatory state present in CTDs.

Myo-inositol Oxygenase as a Novel Marker in the Diagnosis of Acute Kidney Injury

Background

Due to the lack of diagnostic efficiency of serum creatinine in acute kidney injury (AKI), there is a pressing need to develop novel diagnostic markers. Therefore, in this study, we evaluated myo–inositol oxygenase (MIOX), neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C in terms of their applicability in the diagnosis of AKI.

Methods

We enrolled a total of 39 AKI patients and 38 healthy controls in the study. We compared the levels of serum MIOX, NGAL and cystatin C between the two groups.

Results

We found that the concentrations of serum creatinine, blood-urea nitrogen, MIOX and cystatin C were higher in the AKI group. According to the receiver operating characteristic analysis, the area under the curve (AUC) values were 0.694 (95% CI 0.579-0.794) for MIOX and 0.976 (95% CI; 0.912-0.997) for cystatin C. For MIOX, when the cut-off concentration was set to 77.3 pg/mL, the diagnostic sensitivity and specificity were found to be 53.8% (95% CI; 37.2-69.9) and 81.5 (95% CI; 65.7-92.3), respectively. For cystatin C, at the cut-off value of 14 mg/L, the diagnostic sensitivity and specificity were 94.8% (95% CI; 82.7-99.4) and 94.7 % (95% CI 82.3-99.4), respectively.

Conclusion

The measurement of serum MIOX and cystatin C levels is valuable for the diagnosis of AKI. Further research is needed for the evaluation of the potential use of MIOX as a kidney-specific enzyme in the early diagnosis of AKI.

Immunologic and endocrine functions of adipose tissue: implications for kidney disease

Excess adiposity can induce adverse sequelae in multiple cell types and organ systems. The transition from the lean to the obese state is characterized by fundamental cellular changes at the level of the adipocyte. These changes affect the local microenvironment within the respective adipose tissue but can also affect nonadipose systems. Adipocytes within fat pads respond to chronic nutrient excess through hyperplasia or hypertrophy, which can differentially affect interorgan crosstalk between various adipose depots and other organs. This crosstalk is dependent on the unique ability of the adipocyte to coordinate metabolic adjustments throughout the body and to integrate responses to maintain metabolic homeostasis. These actions occur through the release of free fatty acids and metabolites during times of energy need - a process that is altered in the obese state. In addition, adipocytes release a wide array of signalling molecules, such as sphingolipids, as well as inflammatory and hormonal factors (adipokines) that are critical for interorgan crosstalk. The interactions of adipose tissue with the kidney - referred to as the adipo-renal axis - are important for normal kidney function as well as the response of the kidney to injury. Here, we discuss the mechanistic basis of this interorgan crosstalk, which clearly has great therapeutic potential given the increasing rates of chronic kidney disease secondary to obesity and type 2 diabetes mellitus.

Alterations of HDL Particles in Children with End-stage Renal Disease

Background

Unfavorable lipid profile presents one of most important risk factor for cardiovascular disease in renal pathology. Myeloperoxidase (MPO) as enzyme which oxidizes lipoproteins and paraoxonase1 (PON1) as anti-oxidative enzyme have been involved in pathogenesis of cardiovascular disease. In the present study we sought to assess oxidative stress status, lipoprotein subclasses distribution as well as functionality of high density lipoprotein (HDL) trough MPO/PON1 ratio in children with chronic kidney disease (CKD) and children after renal transplantation.

Methods

PON1 activity and oxidative stress parameters were measured spectrophotometrically, while MPO concentration was determined using immunoassay. Separation of lipoprotein subclasses was performed by vertical gradient gel electrophoresis in 19 children with different stage of CKD and 19 post-transplantation patients (PT).

Results

CKD patients had increased MPO/PON1 ratio and higher prevalence of smaller HDL subclasses when compared to PT subjects. Also, there was a significant positive correlation between MPO level and MPO/PON1 ratio with relative proportion of smaller HDL subclasses.

Conclusion

Children with CKD have impaired HDL distribution that is improved after kidney transplantation. Since that measurement of HDL distribution and functionality are not routinely available, MPO/PON1 ratio may be useful marker that could provide necessary information.

Screening for Chronic Kidney Disease in Adult Males in Vojvodina: A Cross-sectional Study

BACKGROUND

Chronic kidney disease (CKD) is one of the most significant global health problems accompanied by numerous complicatons, with constant increase in the number of affected people. This number is much higher in early phases of disease and patients are mostly asymptomatic, so early detection of CKD is crucial. The aim was examination of the prevalence of CKD in the general population of males in Vojvodina, based on estimated glomerular filtration rate (eGFR) and urine albumin/creatinine ratio (ACR), and exploring the determinants and awareness of CKD.

METHODS

This cross-sectional study included 3060 male examinees from the general population, over 18 years of age, whose eGFR and ACR were calculated, first morning urine specimen examined, arterial blood pressure measured and body mass index calculated. Standard biochemistry methods determined creatinine, urea, uric acid and glucose serum concentrations as well as albumin and creatinine urine levels.

RESULTS

Prevalence of CKD in the adult male population is 7.9%, highest in men over 65 years of age (46.7%), while in the other age groups it is 3.6-12.6%. The largest number of examinees with a positive CKD marker suffer from arterial hypertension (HTA) and diabetes mellitus (DM). Only 1.3% of examinees with eGFR<60 ml/min/1.73 m2 and/or ACR≥ 3 mg/mmol had been aware of positive CKD biomarkers.

CONCLUSIONS

Obtained results show the prevalence of CKD in adult males is 7.9%, HTA and DM are the most important CKD risk factors and the level of CKD awareness is extremely low (1.3%) indicating the necessity for introduction of early stage disease recognition measures, including raising CKD awareness.

Interpretation of Erythropoietin and Haemoglobin Levels in Patients with Various Stages of Chronic Kidney Disease

BACKGROUND

The production of erythrocytes is regulated by the hormone erythropoietin (EPO), which maintains the blood haemoglobin (Hb) levels constant under normal conditions. Human EPO is a glycoprotein hormone and its synthesis is controlled by the hypoxia-inducible transcription factor. The aim of this study was to establish EPO and Hb levels in patients with chronic kidney disease (CKD), as well as in control subjects, and to investigate the relationship between these parameters.

METHODS

This cross-sectional, observational study included 356 subjects with CKD divided into 4 subgroups according to their glomerular filtration rate (GFR). The control group consisted of 206 age and sex matched healthy subjects with GFR rate ≥90 mL/min/1.73 m2. EPO, Hb and serum creatinine levels were determined by using immunochemical and spectrophotometric methods. GFR was determined using the MDRD formula.

RESULTS

The CKD patients had significantly lower levels of haemoglobin (p<0.0005) and hematocrit (p<0.0005) compared to control group. Our results showed that Hb levels decreased, whereas serum creatinine increased with the increasing renal failure. The CKD patients in all four groups had significantly lower (p<0.0005) Hb levels, and significantly higher (p<0.0005) creatinine levels compared to the control group. The median EPO in group I and II were significantly higher (p=0.002; p=0.018), while median EPO in group III and IV were significantly lower (p=0.03; p=0.011) compared to the control group.

CONCLUSIONS

In patients with CKD, GFR positively correlated with Hb and EPO, while the correlation between GFR and serum creatinine was negative.