Creatine metabolism and safety profiles after six-week oral guanidinoacetic acid administration in healthy humans

OBJECTIVES

Guanidinoacetic acid (GAA) is a natural precursor of creatine, yet the potential use of GAA as a nutritional additive for restoring creatine availability in humans has been limited by unclear efficacy and safety after exogenous GAA administration. The present study evaluated the effects of orally administered GAA on serum and urinary GAA, creatine and creatinine concentration, and on the occurrence of adverse events in healthy humans.

METHODS AND RESULTS

Twenty-four healthy volunteers were randomized in a double-blind design to receive either GAA (2.4 grams daily) or placebo (PLA) by oral administration for 6 weeks.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov, identification number NCT01133899. Serum creatine and creatinine increased significantly from before to after administration in GAA-supplemented participants (P < 0.05). The proportion of participants who reported minor side effects was 58.3% in the GAA group and 45.5% in the placebo group (P = 0.68). A few participants experienced serum creatine levels above 70 µmol/L.

CONCLUSION

Exogenous GAA is metabolized to creatine, resulting in a significant increase of fasting serum creatine after intervention. GAA had an acceptable side-effects profile with a low incidence of biochemical abnormalities.

Renal markers in normal and hypertensive disorders of pregnancy in Indian women: a pilot study

BACKGROUND

Altered renal function is an essential component of the pathophysiological process in pre-eclampsia. Kidneys play an important role in the turnover of low molecular weight substances such as creatinine, uric acid and cystatin C. The present study was undertaken if these serum markers were characteristically altered in Indian pregnant women.

METHODS

Serum levels were therefore determined in samples from 69 healthy women at term as well as in 27 samples of patients with Pregnancy induced hypertension (PIH) and in 20 patients with pre-eclampsia (PE).

RESULTS

The levels of all three components were significantly higher in pre-eclamptic patients when compared to healthy controls with the mean ± SD being 1.47 ± 0.9 vs. 1.06 ± 0.2 for cystatin C, 0.95 ± 0.2 vs. 0.67 ± 0.1 for creatinine and 6.13 ± 1.8 vs. 4.28 ±1.1 for uric acid respectively. In PIH cystatin C was significantly higher, 1.25 ± 0.9 unlike creatinine, 0.67 ± 0.14 and uric acid, 4.30 ± 1.0. Receiver operating characteristic (ROC) plots demonstrated that the diagnostic accuracy of serum creatinine was superior to serum uric acid and serum cystatin C and serum uric acid was better than serum cystatin C.

CONCLUSION

The maternal serum cystatin C, creatinine and uric acid were all significantly elevated at the end of pregnancy in pre-eclampsia compared to those of healthy pregnant women. If this rise in the above markers during early pregnancy could predict the onset of PIH/PE, needs to be investigated.

Clinical significance of subjective foamy urine

Foamy urine is widely regarded as a sign of proteinuria. However, there is no objective definition of foamy urine and there are no reports on the proportion of involved patients who have overt proteinuria or microalbuminuria. We performed this study to investigate this proportion and to identify possible risk factors for these two conditions. We reviewed all new outpatients from 1 November 2011 to 30 April 2012 and identified patients complaining of foamy urine. Their demographic data and medical records were examined. In particular, we tabulated the patients' spot urinary protein to creatinine ratio, spot urinary microalbumin to creatinine ratio (ACR), blood urea nitrogen (BUN), and serum levels of creatinine (Cr), uric acid, calcium, phosphate, and glucose. In addition, we calculated estimated glomerular filtration rates (eGFRs) by using the CKD-EPI equation. We also performed risk factor analysis with the Chi-squared test and by logistic regression. Seventy-two patients (6.3% of total new outpatients) complained of foamy urine; of these, there were 59 males with a median age of 65.5 years (range, 36-87 years). Of the 72 patients, 16 (22.2%) had overt proteinuria. We found that diabetes, poor renal function (high Cr, BUN, low eGFR), increased serum phosphate, and increased serum glucose were associated with overt proteinuria. Multiple logistic regression analysis showed that serum Cr and serum phosphate were associated with overt proteinuria. The ACR was available for 38 patients, and in this subgroup, 12 (31.6%) showed microalbuminuria or overt proteinuria. In this subgroup, a high serum Cr was the only statistically significant risk factor. Among patients who complained of foamy urine, approximately 20% had overt proteinuria, and increased serum Cr and phosphate were statistically significant risk factors.

Comparative effect of olive oil and fish oil supplementation in combating gentamicin induced nephrotoxicity in rats

The present study is related to the comparative effects of fish oil and olive oil supplementation on gentamicin induced nephrotoxicity in rats. Three treatment groups (Pretrement, Co-treatment and post treatment) were chosen for the study. Nephrotoxicity in rats was induced by intraperitonial administration of gentamicin (80 mg/kg/d) for 3,5,7,10,& 12 consecutive days. The animals were sacrificed 12 hrs after last treatment in each group. The maximum nephrotoxicity was developed on 10 days treatment of gentamicin. For each group a control group was taken without any oil or gentamicin treatment. Beneficial effects of oils were evidenced by reduced serum urea and creatinine concentrations in the group receiving oils compared to the non oil treatment animals receiving gentamicin only. Further, the changed values of alkaline phosphatase and acid phosphatase activity retumed to normal in kidney and liver tissue homogenates after fish and olive oil treatment. In this study, it was found that co-treatment of fish and olive oil is more effective antagonist of gentamicin induced nephrotoxicity. However fish oil was found to be more effective. Hypercholesteromia associated with gentamicin induced nephrotoxicity is also lowered by oil supplementations. The beneficial effects of these oils are due to counteracting effect of the biochemical alterations induced by the drug.

Creatinine, urea, uric acid, water and electrolytes renal handling in the healthy oldest old

Renal physiology in the healthy oldest old has the following characteristics, in comparison with the renal physiology in the young: a reduced creatinine clearance, tubular pattern of creatinine back-filtration, preserved proximal tubule sodium reabsorption and uric acid secretion, reduced sodium reabsorption in the thick ascending loop of Henle, reduced free water clearance, increased urea excretion, presence of medulla hypotonicity, reduced urinary dilution and concentration capabilities, and finally a reduced collecting tubules response to furosemide which expresses a reduced potassium excretion in this segment due to a sort of aldosterone resistance. All physiological changes of the aged kidney are the same in both genders.

A comparison of serum cystatin C and creatinine with glomerular filtration rate in Indian patients with chronic kidney disease

OBJECTIVES

There is no literature available on the performance of cystatin C in Chronic Kidney Disease (CKD) patients of Indian population based on age group. Hence, this study is aimed to compare the diagnostic performance of serum cystatin C and creatinine with measured glomerular filtration rate (GFR) and estimated GFR (eGFR) in subjects of Indian origin.

METHODS

The study was carried out at Tiruchirappalli, South India during the period of September 2010 to march 2011. One hundred and six CKD patients (82 males, 24 females) were enrolled and categorized into three groups based on age. The eGFR was calculated using Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) formulae. Serum cystatin C was measured with a particle-enhanced nephelometric immunoassay (PENIA) method. GFR was measured using (99m)T(C) - diethylene triamine penta aceticacid (DTPA) renal scan method.

RESULTS

Serum cystatin C showed significant correlation with measured GFR in all the three groups (r=-0.9735, r=-0.8975 and r=-0.7994 respectively) than serum creatinine (r=-0.7380, r=-0.6852 and r=-0.5127 respectively).

CONCLUSION

Serum cystatin C showed a high correlation with measured GFR in young and older patients with CKD than creatinine. Thus, cystatin C is a good alternative marker to creatinine in CKD patients.

Color Doppler indexes in early phase after kidney transplantation and their association with kidney function on six month follow up

BACKGROUND

Doppler ultrasonography (DU) and measurement of its indexes, resistive index (RI) and pulsatility index (PI), is used to investigate transplanted kidney hemodynamic status and function. The aim of this study was to determine the correlation between Doppler indexes in the early phase after transplantation with long-term transplanted kidney function.

MATERIALS AND METHODS

In this cross-sectional study on 38 newly kidney transplant patients, we performed DU with assessment of its indexes within 48 hours, 1 week, and 6 months after kidney transplantation. Serum creatinine after stability and 6 months after kidney transplantation were assessed. Cyclosporine level was measured 1 week after kidney transplantation and compared with DU indexes.

RESULTS

About 71% of kidney transplanted patients reached their normal initial creatinine level(cr<1.5 mg/ dl) and 28% of all patients were involved in kidney dysfunction after 6 months (increase in basic creatinine level more than 25%).There was no significant difference between mean RI and PI in patients with normal and disturbed kidney function based on creatinine level in early posttransplantation period but there was linear correlation between mean RI and PI within 48 hours and 1 week with kidney function after 6 months. Also no association between cyclosporine level and RI and PI was shown. There was a direct association between age and the levels of RI and PI 6 months after transplantation.

CONCLUSION

This study suggests assessment of RI and PI in early period after transplantation and can be used as predictive parameters for long-term function of transplanted kidney and RI more than 0.80 in early phase after transplantation has an acceptable sensitivity and specificity to predict long-term kidney dysfunction.

The effect of exercise on urinary gamma-glutamyltransferase and protein levels in elite female karate athletes

PURPOSE

Post exercise proteinuria and increased urinary Gamma-Glutamyl transferase (GGT) levels can be indicative of exercise-induced renal damage. The aim of this investigation is to study the effect of one session of intensive training on renal damage markers and compare their values to those 6 hours after training.

METHODS

In this cross-sectional study with pre- and post-test design, 10 elite volunteer female athletes were selected and participated in one training session (2 hours). Urine samples were collected before training, one hour after training, and 6 hours after training. Urinary protein (Pr), creatinine (Cr), and GGT values were measured through laboratory methods and then Pr/Cr and GGT/Cr ratios were computed.

RESULTS

There were significant differences between values of protein, GGT and Creatinine in the three sampling phases (P<0.05). However, no significant differences were observed between values for GGT/Cr and Pr/Cr ratio. There were significant differences between the mean values of Creatinine, protein and GGT within pre-exercise and 1 hour post-exercise and within 1 hour post-exercise and 6 hours post-exercise (P<0.05).

CONCLUSION

It seems that a session of karate training does not result in renal damage and athletes can continue training after 6 hours.

Serum biochemical changes in rabbits on a regular diet with and without flax lignan complex following a high-cholesterol diet

BACKGROUND

Flax lignan complex (FLC) isolated from flaxseed suppresses development of hypercholesterolemic atherosclerosis. It does not produce regression of atherosclerosis, but prevents its regular diet-induced acceleration following a high-cholesterol diet. It is not known if replacement of a high-cholesterol diet with a regular diet has deleterious effects on body organs.

OBJECTIVES

To determine if short-term use of a high-cholesterol diet, and a regular diet with or without FLC following the high-cholesterol diet, have any adverse effects on serum electrolytes, glucose and enzymes related to the liver, kidneys, skeletal muscle and intestines.

METHODS

Blood samples were collected from the rabbits before and at various intervals during the high-cholesterol diet, and while on the regular diet with or without FLC, following the high-cholesterol diet. Measurements of serum total cholesterol, glucose, aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), albumin, creatinine, electrolytes (sodium [Na], potassium [K], chloride [Cl]) and carbon dioxide (CO(2)) were taken.

RESULTS

The high-cholesterol diet produced hypercholesterolemia, which was associated with reductions in serum glucose and no significant changes in serum Na, K, Cl, CO(2), ALT, ALP, AST, GGT, albumin or creatinine. Regular diet with or without FLC, following the high-cholesterol diet, reduced serum total cholesterol and glucose, increased serum Na, Cl and creatinine, but produced no significant alterations in serum K, CO(2), ALT, AST, GGT or albumin. FLC reduced serum ALP, but regular diet produced no significant change.

CONCLUSION

Short-term use of a high-cholesterol diet, or a regular diet with or without FLC following the high-cholesterol diet, does not produce deleterious effects in the liver, kidneys, skeletal muscle, intestine or bone, as shown by changes in serum electrolytes, glucose and enzymes.

Science behind cisplatin-induced nephrotoxicity in humans: a clinical study

OBJECTIVE

To investigate the relationship between serum electrolyte changes and cisplatin induced nephrotoxicity.

METHODS

We collected data from 18 patients undergoing cisplatin chemotherapy including serum electrolytes, creatinine, blood urea nitrogen (BUN) and urine potassium, sodium and pH levels before and after the cisplatin chemotherapy. All the patients had cancer and were treated with 40-50 mg/day cisplatin. Renal injury was assessed by measuring serum electrolytes, creatinine, BUN levels and urine potassium, sodium and pH levels.

RESULTS

The five cycles of cisplatin based chemotherapy resulted in hypomagnesia (P=0.029), hypocalcaemia (P=0.001*), hypophosphatemia (P=0.003*), hypokalemia (P=0.001*) and increased serum creatinine (P=0.001*) and BUN (P=0.292*) levels. In urine analysis, decrease in potassium (P=0.024*) was found, except potassium there was no significant changes in sodium and urine pH.

CONCLUSIONS

The present study demonstrates that, acute nephrotoxicity was observed in patients with different types of cancers undergoing cisplatin based chemotherapy due to electrolyte disturbances, when no corrective measures were initiated.

Comparison of serum cystatin C and creatinine as a marker for early detection of decreasing glomerular filtration rate in renal transplants

Purpose

We wished to compare the clinical effectiveness of cystatin C (CyC) and serum creatinine (sCr) to assess renal function in renal transplantation patients.

Methods

We compared the clinical effectiveness of CyC with that of the sCr to estimate 24-hour urine creatinine clearance (CrCl) in 72 adult recipients who underwent renal transplantation from January 2001 to December 2008. We analyzed the data in terms of accuracy, bias, precision and sensitivity as a function of length of time posttransplantation and CrCl value.

Results

The patients were divided into four groups according to CrCl value <30, <60, <90, and ≥90 mL/min/1.73 m². The corresponding Cr-based glomerular filtration rate (GFR) estimates had accuracies of 0.71, 0.906, 0.963, and 1.00 within 50% of the reference, with biases (mean percentage errors) of 4.7, 5.32, -5.79, -31.33 mL/min/1.73 m², and precisions (mean absolute percentage errors) of 7.57, 10.03, 14.52, and 31.33 mL/min/1.73 m², respectively. The CyC-based GFR estimates had accuracies of 0.35, 0.79, 0.93, and 0.67 within 50% of the reference, respectively, with biases of 15.03, 13.37, -5.58, and -34.79 mL/min/1.73 m² and precisions of 15.03, 14.80, 17.91, and 34.79 mL/min/1.73 m². The sensitivity for detecting GFR below 60 mL/min/1.73 m² was higher for CyC (0.96, 1, and 0.95) than for Cr (0.77, 0.75, and 0.82).

Conclusion

CyC is a more sensitive indicator of low GFR (CrCl <60 mL/min/1.73 m²) than sCr. However, CyC-based GFR estimates are restrictive data, and are neither accurate nor specific. Therefore, to evaluate renal function, we may need a revised CyC-based GFR formula and close monitoring of sCr.

Effect of sevoflurane on grafted kidney function in renal transplantation

BACKGROUND

The objective of this retrospective study was to determine if there are any differences in grafted kidney function in recipients of kidney transplantation (KT) when donors and recipients were anesthetized with sevoflurane compared to desflurane.

METHODS

Seventy-three pairs of donors-recipients were anesthetized with sevoflurane (Sevo group) and 71 pairs were anesthetized with desflurane (Des group). We retrospectively investigated the blood urea nitrogen (BUN) levels, creatinine (Cr) levels, and estimated glomerular filtration rates (eGFR) of the recipients in both groups for 1 year postoperatively. We tested non-inferiority for serum creatinine at discharge and 1 year after KT. Short-term (1 year) outcomes of KT were assessed by the incidence of delayed graft function (DGF), acute rejection episodes (ARE), and graft failure.

RESULTS

There were no differences in BUN, Cr, eGFR, or outcomes of KT at 1 year postoperatively. Specifically, the 95% confidence interval for the difference in creatinine levels between the Sevo and Des groups was less than the margin of equivalence at the time of discharge and 1 year after surgery. The occurrences of DGF, ARE, and graft failure were comparable between the groups.

CONCLUSIONS

Compared to desflurane, sevoflurane had no adverse effects on grafted renal function or on the short-term outcome of renal transplantation.

Challenges facing early detection of acute kidney injury in the critically ill

Recent advances in the detection of acute kidney injury (AKI) afford the possibility of early intervention. Proteomics and genomics have identified many markers of tubular cell injury, some of which are manifest in the urine. One trial has used novel injury biomarkers to recruit patients to an intervention prior to an elevation in plasma creatinine. This trial and other recent studies have shown that the use of biomarkers of injury will depend on the time the patient presents following insult to the kidney, the likely cause of that insult, and the pre-injury renal function of that patient. The definition of AKI is likely to change in the near future to include a measure of injury. We anticipate novel therapies becoming available following successful trials that utilize the methodology of early intervention following an elevated injury biomarker.

The Effects of Muscle Mass on Homocyst(e)ine Levels in Plasma and Urine

The present study was designed to examine the relationship between homocyst(e)ine (H[e]) levels and muscle mass. Two experimental groups each of 24 Caucasian males, one consisting of higher-muscle mass subjects (HMM) and the other of lower-muscle mass subjects (LMM) participated in this study. Muscle mass was estimated from 24-hour urine collections of creatinine (Crt). Muscle mass was 40.3 ± 15.9 kg in HMM and 37.2 ± 11.4 kg in LMM (P= 0.002). Mean plasma H(e) levels in HMM were 10.29 ± 2.9 nmol/mL, and in LMM were 10.02 ± 2.4 nmol/L (Not significant, [NS]). Urinary H(e) levels (UH[e]) were 9.95 ± 4.3 nmol/mL and 9.22 ± 2.9 nmol/mL for HMM and LMM, respectively (NS). Plasma H(e) levels correlated well with UH(e) (HMM: r= 0.58, P= 0.009; LMM: r= 0.66, P= 0.004). Muscle mass and was not correlated to either plasma H(e) or UH(e). However, in HMM trends were identified for body mass to be correlated with UH(e) (r= 0.39, P= 0.10) and UCrt (r= 0.41, P= 0.08). Surprisingly, in HMM plasma and UCrt were only weakly correlated (r= 0.44, P= 0.06). Our results do not support a causal relationship between the amount of muscle mass and H(e) levels in plasma or urine.

Absorption and excretion of cranberry-derived phenolics in humans

Absorption and excretion of twenty cranberry-derived phenolics were studied following the consumption of cranberry juice, sauces, and fruits by healthy human volunteers. Plasma and urine samples were collected and analysed by gas chromatography-mass spectrometry (GC-MS). A high performance liquid chromatography (HPLC) method was employed for analysing urinary creatinine, which was used as a normalisation agent. Significant increases in the sum of plasma phenolics were observed with different concentration peaks (between 0.5 and 2h) for individual subjects. Some of the phenolics, such as trans-cinnamic, vanillic, p-coumaric acids, and catechin showed second plasma concentration peaks. All of cranberry-derived phenolics increased significantly in urine samples after the intake of each cranberry product. The high molecular weight quercetin and myricetin, which were abundant in cranberry foodstuffs, were not found in either plasma or urine samples. This study provided the fundamental information for understanding the absorption and excretion of phenolics in the human gastrointestinal system after dietary intake of cranberry products.

Blood chemical changes and renal histological alterations induced by gentamicin in rats

Gentamicin is an effective widely used antibiotic, but the risk of nephrotoxicity and oxidative damage limit its long-term use. Hence, the current study aims to elucidate such hazardous effects. To achieve the study aim male Wistar albino rats (Rattus norvegicus) were exposed to gentamicin to investigate the resultant blood chemical changes and renal histological alterations. In comparison with control rats, gentamicin produced outstanding tubular, glomerular and interstitial alterations that included degeneration, necrosis, cytolysis and cortical tubular desquamation together with mesangial hypercellularity, endothelial cell proliferation and blood capillary congestion. Compared with control animals significant blood chemical changes (P < 0.05) including free radicals, ALT, AST, ALP, serum creatinine and serum urea were recorded in gentamicin-injected animals. The findings revealed that exposure to gentamicin can induce significant histological alterations in the kidney as well as remarkable blood chemical changes that might indicate marked renal failure.

Serum cystatin C reflects the progress of albuminuria

BACKGROUND

Research on the relationship between urinary albumin excretion and serum cystatin C in diabetes is restricted to cross-sectional studies. In this study, we investigated how well serial measurements of serum cystatin C level reflect changes in the urinary albumin excretion rate.

METHODS

We enrolled and retrospectively collected data on 1,058 participants with type 2 diabetes who were older than 18 years and who had more than 3 years of follow-up with serial measurements of albuminuria and serum cystatin C at an outpatient clinic.

RESULTS

With the use of a linear mixed model, we found that the albuminuria level for each patient over time corresponded with the annual change in serum cystatin C-based estimated glomerular filtration rate (cysC-eGFR) but did not correspond with the creatinine-based eGFR calculated by the modification of diet in renal disease formula (MDRD-eGFR). The discrepancy in the direction of the trend was smaller with cysC-eGFR than with MDRD-eGFR.

CONCLUSION

Serum cystatin C level reflects the trend in albuminuria level more accurately than serum creatinine level in Korean type 2 diabetes mellitus patients.

Cardiorenal syndromes

Cardiorenal syndromes (CRS) have been subclassified as five defined entities which represent clinical circumstances in which both the heart and the kidney are involved in a bidirectional injury and dysfunction via a final common pathway of cell-to-cell death and accelerated apoptosis mediated by oxidative stress. Types 1 and 2 involve acute and chronic cardiovascular disease (CVD) scenarios leading to acute kidney injury or accelerated chronic kidney disease. Types 2 and 3 describe acute and chronic kidney disease leading primarily to heart failure, although it is possible that acute coronary syndromes, stroke, and arrhythmias could be CVD outcomes in these forms of CRS. Finally, CRS type 5 describes a simultaneous insult to both heart and kidneys, such as sepsis, where both organs are injured simultaneously. Both blood and urine biomarkers are reviewed in this paper and offer a considerable opportunity to enhance the understanding of the pathophysiology and known epidemiology of these recently defined syndromes.

Experience without using venoveno bypass in adult orthotopic liver transplantation

BACKGROUND

Venoveno bypass (VVB) has been used to achieve hemodynamic stability and decrease the incidence of renal dysfunction. However, VVB has many complications. The purpose of this study is to verify the safety of total clamping of the suprahepatic inferior vena cava (IVC) without VVB during orthotropic liver transplantation (OLT) in terms of anesthetic management.

METHODS

Twenty-five patients without preoperative renal dysfunction who underwent primary OLT were enrolled in this study. Hemodynamic data and blood gas measurements were collected 1 hour after incision, 30 minutes after IVC total clamping and 30 minutes after reperfusion. Postoperative laboratory data, including blood urea nitrogen (BUN), creatinine (Cr) and glomerular filtration rate (GFR), were assessed at postoperative day (POD) 0-7, 30, 90, 180 and 1 year.

RESULTS

Mean blood pressure was well maintained during IVC total clamping with infusion of inotropics. There was no case of severe acidosis (pH < 7.2) during the anhepatic period. The immediate postoperative Cr and GFR were not significantly different from those of the preoperative values. BUN increased from POD 1 and decreased after POD 6, while Cr increased at POD 90 only.

CONCLUSIONS

In patients without preoperative renal dysfunction, when IVC was totally clamped, VVB does not need to be routinely performed to maintain hemodynamics during the anhepatic phase and renal function after OLT.

Serum cystatin C levels in renal transplant recipients

Cystatin C is an emerging parameter for the assessment of renal allograft function. The objective of the study was to compare the efficacy of serum cystatin C (SCys) with the established parameter serum creatinine (SCr) in the assessment of renal function in renal transplant recipients (RTR). The glomerular filtration rate (GFR) of 30 renal transplant patients and 29 control subjects was determined using (99m)Tc Diethylene-triamine-penta-acetate (DTPA) method. SCr was measured using an automated Jaffe's assay and SCys was measured using latex particle enhanced turbidimetric immuno assay (PETIA). The modification of diet in renal disease (MDRD) formula was used to calculate GFR from SCr, while the Le Bricon formula was used to derive GFR based on SCys. Statistical analysis was performed using MedCalc software. SCr and SCys levels were significantly higher, while DTPA clearance was significantly lower in RTR (P < 0.0001) when compared with controls. The correlation coefficient (r value) between calculated GFR based on MDRD method and DTPA clearance was 0.343 (P = 0.06) while the calculated GFR based on Le Bricon formula was 0.694 (P < 0.001). The results have shown that SCys is a better parameter than SCr in assessing renal function in RTR. The inclusion of SCys as an additional parameter would certainly help in detection of even a marginal decline in renal function and also in adjusting the dosage of immunosuppressive drugs.

Change in renal function after sodium phosphate preparation for screening colonoscopy

AIM: To investigate the changes in renal function at 12-24 mo in patients following sodium phosphate (NaP) preparation for screening colonoscopy.

METHODS: We carried out a retrospective study on the results from patients who received health check-up services as part of an employer-provided wellness program performed between August 2006 and May 2008 and who were followed up for 12-24 mo. Prior to screening colonoscopy, 224 patients underwent bowel cleansing with NaP (NaP group) and 113 patients with polyethylene glycol (PEG group). The control group comprised 672 age-matched patients. We compared the changes in the creatinine levels and the glomerular filtration rates (GFRs) from baseline to 12-24 mo between the NaP, PEG, and control groups using two-way repeated measured analysis of variance. In addition, multivariate linear regression analysis was performed to assess the risk factors for a decreased GFR.

RESULTS: The baseline mean serum creatinine level in the NaP, PEG, and control groups was 1.12 ± 0.15, 1.12 ± 0.16, and 1.12 ± 0.15 mg/dL, which increased to 1.15 ± 0.15, 1.15 ± 0.18, and 1.15 ± 0.15 mg/dL, respectively, after 12-24 mo. The baseline mean GFR in the NaP, PEG, and control groups was 69.0 ± 7.7, 68.9 ± 8.0, and 69.6 ± 6.7 mL/min per 1.73 m², which decreased to 66.5 ± 7.8, 66.5 ± 8.3, and 67.4 ± 6.4 mL/min per 1.73 m², respectively, after 12-24 mo. The changes in serum creatinine levels and GFRs were not significantly between the NaP, PEG, and control groups (P = 0.992 and P = 0.233, respectively). Using multivariate linear regression analysis, only the baseline GFR was associated with the change in GFR (P < 0.001). Indeed, the bowel preparations were not associated with the change in GFR (P = 0.297).

CONCLUSION: NaP bowel preparation in subjects with normal renal function was not associated with renal injury, and NaP can thus be used safely for screening colonoscopy.

Renal Function Recovery in Donors and Recipients after Live Donor Nephrectomy: Hand-Assisted Laparoscopic vs. Open Procedures

Purpose

Laparoscopic donor nephrectomy is associated with less postoperative pain and faster recovery times in living kidney donors. However, pneumoperitoneum, which is required in laparoscopic donor nephrectomy, can result in adverse effects on renal function in donors and recipients. We compared renal function in donors and recipients after hand-assisted laparoscopic donor nephrectomy (HALDN) and open donor nephrectomy (ODN).

Materials and Methods

Between January 1997 and January 2008, 241 live donor nephrectomies were performed by either HALDN (n=118) or ODN (n=123). Preoperative patient characteristics were not significantly different between the donors and recipients. We monitored the changes in serum creatinine levels of the donors and recipients preoperatively and on postoperative days 1, 5, 28, 84, and 365.

Results

The mean operative times of HALDN and ODN were 171 and 163 minutes (p=0.284), and the mean warm ischemic times were 292 and 236 seconds (p=0.207), respectively. The mean serum creatinine level in the recipients on postoperative day 1 was significantly higher after HALDN than after ODN (3.48 vs. 2.62 mg/dl, p=0.003). However, from postoperative day 5 to 1 year, there was no significant difference between the two groups. The mean serum creatinine level in the donors was not significantly different between the HALDN and ODN groups throughout the study period.

Conclusions

Renal function recovery in the donors was similar with both HALDN and ODN. Graft renal function recovery after HALDN was comparable with that after ODN, except immediately after surgery (postoperative day 1).

Major determinants of serum homocysteine concentrations in a Korean population

The objective of this study was to identify the factors that determine serum homocysteine concentrations in Korean population. In a community-based study, 871 participants completed detailed questionnaires and physical examination. We found that increased age, male sex, family history of stroke, deficiencies of serum folate and vitamin B12, and elevated serum creatinine significantly increased the risk of hyperhomocysteinemia. However, hormonal and behavioral factors (smoking, alcohol drinking, coffee consumption, and sedentary time) were not associated with the risk of hyperhomocysteinemia. The risk of hyperhomocysteinemia was steeply increased in subjects with two or more risk factors among four selected risk factors (deficiencies of serum folate and vitamin B12, elevated creatinine, and family history of stroke) compared to subjects who did not have any risk factors, especially subjects over the age of 65 yr (odds ratio [OR], 33.5; 95% confidence interval [CI], 3.71-302.0 in men; OR, 39.2; 95% CI, 7.95-193.2 in women). In conclusion, increased age, male sex, family history of stroke, deficiencies of serum folate and vitamin B12, and elevated serum creatinine are important determinants of serum homocysteine concentrations with interaction effects between these factors.

Markers of renal function tests

BACKGROUND

The markers of renal function test assess the normal functioning of kidneys. These markers may be radioactive and non radioactive. They indicate the glomerular filtration rate, concentrating and diluting capacity of kidneys (tubular function). If there is an increase or decrease in the valves of these markers it indicates dysfunction of kidney.

AIM

The aim of this review is to compare and analyze the present and newer markers of renal function tests which help in diagnosis of clinical disorders. MATERIAL #ENTITYSTARTX00026;

METHODS

An extensive literature survey was done aiming to compare and compile renal function tests makers required in diagnosis of diseases.

RESULTS

Creatinine, urea, uric acid and electrolytes are makers for routine analysis whereas several studies have confirmed and consolidated the usefulness of markers such as cystatin C and β-Trace Protein.

CONCLUSION

We conclude that further investigation is necessary to define these biomarkers in terms of usefulness in assessing renal function.

Effect of hemodialysis on circulating cystatin c levels in patients with end stage renal disease

Plasma cystatin C is an emerging parameter to assess kidney function. Its utility in assessing the adequacy of hemodialysis in patients with end-stage-renal disease has however not been established with certainty. This study was therefore carried out to assess the usefulness of serum cystatin C estimation in patients undergoing low flux membrane hemodialysis. Serum creatinine and cystatin C were estimated in 20 patients before and after undergoing hemodialysis. The mean serum creatinine decreased from a pre-dialysis value of 7.72 mg/dL to a post-dialysis value of 2.90 mg/dL. On the contrary, the mean serum cystatin C levels were found to increase from a pre-dialysis value of 5.97 mg/L to a post-dialysis value of 8.25 mg/L. Therefore, serum cystatin C cannot be used to monitor dialysis adequacy. It however, serves as a surrogate marker of the inadequacy of low flux membrane bicarbonate hemodialysis in clearing low molecular weight proteins from the circulation.

Serum cystatin C is a potential endogenous marker for the estimation of renal function in male gout patients with renal impairment

Serum creatinine level is the most commonly used indices for assessment of glomerular filtration rate (GFR), even though these indices have been shown to have some limitations in clinical practice. We investigated the diagnostic efficacy of serum cystatin C compared to that of serum creatinine levels and identified the relating factors associated with changes in serum cystatin C levels in gout patients with renal impairment. A total of 68 gouty patients with renal impairment were enrolled in this study. Diagnostic efficacy of serum cystatin C levels was evaluated through non-parametric receiver operating characteristic (ROC) analysis. The risk factors for changes in serum cystatin C levels were confirmed using multivariate regression analysis. With 24-hr urine creatinine clearance (Ccr) as the reference for GFR, 1/cystatin C (r=0.702, P<0.001) showed a significantly higher correlation with Ccr than 1/creatinine (r=0.665, P<0.001). Multivariate correlation analysis demonstrated that the clinical parameters for increased serum cystatin C are a higher stage of chronic kidney disease, older age, use of allopurinol, and lower high density lipoprotein-cholesterol. The area under the curve (AUC) at ROC plots identified that of serum cystatin C was significantly greater than that of serum creatinine (AUC 0.804 of cystatin C and AUC 0.745 of creatinine). The study suggests that serum cystatin C is a reliable endogenous marker for the assessment of renal function or GFR in gout patients with renal impairment.

Biochemical markers of liver and kidney function are influenced by thyroid function-a case-controlled follow up study in Indian hypothyroid subjects

Thyroid hormones regulate the renal hemodynamics and basal metabolic rate of most cells. This hospital-based case-control study was done to evaluate the changes in biochemical markers of liver and kidney function in hypothyroid subjects before and after treatment. The study included 176 subjects randomly selected from Thyroid clinics. Serum T(3), T(4), TSH, Liver and Kidney Function tests were analysed using standard kits. Forty-six hypothyroid patients were re-evaluated 6 weeks after thyroxine substitution therapy. Hypothyroid subjects (n=80) showed significantly raised serum creatinine and uric acid levels as compared to euthyroid subjects (n=96). After 6 weeks of thyroxine replacement, serum creatinine and uric acid decreased significantly and were comparable to euthyroid group. A positive correlation of ALT, AST, uric acid, protein and albumin with TSH levels (p<0.05) and negative correlation of serum T(4) levels with ALT, AST, proteins (p<0.05) was observed in the hypothyroid group. Hypothyroidism results in reversible impairment of hepatorenal function.

Kidney function and estimated vascular risk in patients with primary dyslipidemia

Background:

Chronic kidney disease (CKD) is associated with increased vascular risk. Some studies suggested that considering markers of CKD might improve the predictive accuracy of the Framingham risk equation.

Aim:

To evaluate the links between kidney function and risk stratification in patients with primary dyslipidemia.

Methods:

Dyslipidemic patients (n = 156; 83 men) who were non-smokers, did not have diabetes mellitus or evident vascular disease and were not on lipid-lowering or antihypertensive agents were recruited. Creatinine clearance (CrCl) was estimated using the Cockcroft-Gault equation. Estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) equation. We estimated vascular risk using the Framingham equation.

Results:

In both men and women, there was a significant negative correlation between estimated Framingham risk and both eGFR and CrCl (p < 0.001 for all correlations). When men were divided according to creatinine tertiles, there were no significant differences in any parameter between groups. When men were divided according to either eGFR or CrCl tertiles, all estimated Framingham risks significantly increased as renal function declined (p<0.001 for all trends). When women were divided according to creatinine tertiles, all estimated Framingham risks except for stroke significantly increased as creatinine levels increased. When women were divided according to either eGFR or CrCl tertiles, all estimated Framingham risks significantly increased as renal function declined.

Conclusions:

Estimated vascular risk increases as renal function declines. The possibility that incorporating kidney function in the Framingham equation will improve risk stratification requires further evaluation.

Serum cystatin C as a marker to identify patients with moderately impaired renal function

The low molecular weight protein cystatin C produced by all nucleated cells and eliminated by glomerular filtration is of special benefit as a marker of renal function. A study was therefore undertaken to investigate whether serum cystatin C could be used as a marker to identify patients with moderately impaired renal function. A cross-sectional descriptive hospital based study was carried out and serum cystatin C was measured in fifty subjects aged 12 to 74 years with a 24 hr creatinine clearance estimation done at the same time. The gold standard creatinine clearance was used to compare the predicted glomerular filtration rate measured using serum cystatin C. Predicted glomerular filtration rate gave a sensitivity of 82% and specificity of 68% with a diagnostic cut-off value of 1.25mg/L cystatin C for identification of patients with moderately impaired renal function with a single random blood sample.

PREDICTIVE VALUE OF PLASMA UREA: CREATININE RATIO IN PATIENTS PRESENTING WITH MELAENA

The usefulness of plasma urea:creatinine ratio in predicting the site of bleeding was studied in 40 patients admitted with melaena. Patients presenting with frank haematemesis and those in whom the site of bleeding could not be ascertained were excluded from the study. In 26 patients the source of bleeding was above the ligament of Trietz, while in 14 the source was below this level. In 22 of 26 (84.6%) patients with upper gastrointestinal bleeding, the urea:creatinine ratio was more than 36. In only 2 of 14 patients with lower gastrointestinal bleeding the ratio was similarly raised (p < 0.001). Our study suggests that urea:creatinine ratio of 36 or more has a positive predictive value for upper gastrointestinal bleeding.