Urinary π-glutathione S-transferase Predicts Advanced Acute Kidney Injury Following Cardiovascular Surgery

Renal biopsies from donors with acute kidney injury show different molecular patterns according to the post-transplant function

The utilization of kidneys from donors with acute kidney injury (AKI) is often limited by unpredictable post-transplantation outcomes. The aim of our study was to identify protein mediators implicated in either recovery or failure of these organs. Forty kidney biopsies from donors with (20) and without AKI (20) were selected and then subdivided according to the post-transplant outcome defined as a threshold of 45 ml/min for the eGFR at 1 year from transplantation. Tissue homogenates were analysed by western blot to assess how the levels of 17 pre-selected proteins varied across the four groups. Samples from AKI kidneys with a poor outcome showed a fourfold increase in the levels of PPARg and twofold reduction of STAT1 compared to the other groups (p < 0.05). On the contrary, antioxidant enzymes including TRX1 and PRX3 were increased in the AKI kidneys with a good outcome (p < 0.05). An opposite trend was observed for the detoxifying enzyme GSTp which was significantly increased in the AKI group with poor versus good outcome (p < 0.05). The importance of lipid metabolism (PPARg) and inflammatory signals (STAT1) in the function recovery of these kidneys hints to the therapeutical targeting of the involved pathways in the setting of organ reconditioning.

Hepatorenal Syndrome-Novel Insights into Diagnostics and Treatment

Hepatorenal syndrome (HRS) is a disorder associated with cirrhosis and renal impairment, with portal hypertension as its major underlying cause. Moreover, HRS is the third most common cause of acute kidney injury, thus creating a major public health concern. This review summarizes the available information on the pathophysiological implications of HRS. We discuss pathogenesis associated with HRS. Mechanisms such as dysfunction of the circulatory system, bacterial infection, inflammation, impaired renal autoregulation, circulatory, and others, which have been identified as critical pathways for development of HRS, have become easier to diagnose in recent years. Additionally, relatively recently, renal dysfunction biomarkers have been found indicating renal injury, which are involved in the pathophysiology of HRS. This review also summarizes the available information on the management of HRS, focusing on vasoconstrictive drugs, renal replacement therapy, and liver transplant together with currently being investigated novel therapies. Analyzing new discoveries for the underlying causes of this condition assists the general research to improve understanding of the mechanism of pathophysiology and thus prevention of HRS.

Association of urinary liver-type fatty acid-binding protein with outcomes after adrenalectomy for unilateral primary aldosteronism

BACKGROUND AND AIMS

This study explored the association between urinary liver-type fatty acid-binding protein to creatinine (uL-FABP-cre) ratio and postoperative clinical failure in unilateral primary aldosteronism (PA) patients undergoing adrenalectomy.

MATERIALS AND METHODS

Data from the Taiwan Primary Aldosteronism Investigation Group database were analyzed, including patients with unilateral PA who had adrenalectomy between December 2015 and October 2018. Statistical methods included generalized additive modeling, logistic regression analysis, net reclassification improvement (NRI), and the C statistic.

RESULTS

In the study cohort of 131 patients (mean age 52.3 ± 10.8 years; 43.5% male), 117 achieved clinical success, while 14 experienced clinical failure. A uL-FABP-cre ratio ≥5 predicted clinical failure (odds ratio: 6.22, p = 0.005). Subgroup analysis revealed its efficacy in predicting clinical failure in patients with BMI ≥ 24 kg/m2, normokalemia, or <5 years of hypertension. Furthermore, incorporating uL-FABP-cre ratio into the Primary Aldosteronism Surgical Outcome (PASO) score significantly improved predictive ability. The addition increased the C statistic from 0.671 to 0.762 (p < 0.01) and improved category-free NRI by 0.675 (p = 0.014).

CONCLUSION

A uL-FABP-cre ratio ≥5 accurately predicted clinical failure post-adrenalectomy in unilateral PA, enhancing PASO score's identification of high-risk patients for postoperative clinical failure.

Markers of Kidney Tubular Function Deteriorate While Those of Kidney Tubule Health Improve in Primary Aldosteronism After Targeted Treatments

Background Targeted treatment with mineralocorticoid receptor antagonists (MRAs) or adrenalectomy in patients with primary aldosteronism (PA) causes a decline in estimated glomerular filtration rate; however, the associated simultaneous changes in biomarkers of kidney tubule health still remain unclear. Methods and Results We matched 104 patients with newly diagnosed unilateral PA who underwent adrenalectomy with 104 patients with unilateral PA who were treated with MRAs, 104 patients with bilateral PA treated with MRAs, and 104 patients with essential hypertension who served as controls. Functional biomarkers were measured before the targeted treatment and 1 year after treatment, including serum markers of kidney function (cystatin C, creatinine), urinary markers of proximal renal tubular damage (L-FABP [liver-type fatty-acid binding protein], KIM-1 [kidney injury molecule-1]), serum markers of kidney tubular reserve and mineral metabolism (intact parathyroid hormone), and proteinuria. Compared with the patients with essential hypertension, the patients with PA had higher pretreatment serum intact parathyroid hormone and urinary creatinine-corrected parameters, including L-FABP, KIM-1, and albumin. The patients with essential hypertension and with PA had similar cystatin C levels. After treatment with MRAs or adrenalectomy of unilateral PA and MRAs of bilateral PA, the patients with PA had increased serum cystatin C and decreased urinary L-FABP/creatinine, KIM-1/creatinine, creatinine-based estimated glomerular filtration rate, intact parathyroid hormone, and proteinuria (all P<0.05). In multivariable regression models, a higher urinary L-FABP/creatinine ratio and older age were significantly correlated with the occurrence of kidney failure (estimated glomerular filtration rate dip ≥30%) in the patients with PA after targeted treatment. Conclusions Compared with the matched patients with essential hypertension, the incident patients with PA at diagnosis had higher levels of several biomarkers, including markers of kidney damage, tubular reserve/mineral metabolism, and proteinuria. Functional kidney failure in the patients with PA after treatment could be predicted by a higher baseline urinary L-FABP/creatinine ratio and older age. After targeted treatments in the patients with bilateral or unilateral PA, these biomarkers of kidney tubule health were restored, but creatinine-based estimated glomerular filtration rate declined, which may therefore reflect hemodynamic changes rather than intrinsic damage to kidney tubular cells.

Neonatal AKI: An update

Neonatal acute kidney injury (AKI) is a common complication, especially in the neonatal intensive care unit, that is associated with long term consequences and poor outcomes. Early detection and treatment is critical. Currently, neonatal AKI is defined with urinary markers and serum creatinine, with limitations on early detection and individual treatment. There have been numerous biomarkers and risk factor scores that have been studied for their ability to predict neonatal AKI. To move towards personalized medicine, neonatal AKI must be categorized into phenotypes and subphenotypes that fully encapsulate the diverse causes and specific treatments. This review aims to advance our understanding of neonatal AKI detection through the use of biomarkers, subphenotypes, and phenotypes to move towards personalized treatment strategies.

Circulating Fibroblast Growth Factor-23 Levels Can Predict Rapid Kidney Function Decline in a Healthy Population: A Community-Based Study

BACKGROUND

Fibroblast growth factor-23 (FGF-23) associates with decreased kidney function in patients with chronic kidney disease (CKD). However, the correlation between circulating FGF-23 levels and the rate of renal function decline in healthy individuals is largely unknown. We aimed to evaluate the predictive performance of FGF-23 for rapid kidney function decline (RKFD) in a community-based study.

METHODS

A total of 2963 people residing in northern Taiwan were enrolled from August 2013 to May 2018 for an annual assessment of kidney function for five years. The baseline estimated glomerular filtration rates (eGFR) were calculated using the 2009 and 2021 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, which aggregates the values of serum creatinine and cystatin C (eGFRcr-cys). The outcome was RKFD-a 15% decrease in estimated glomerular filtration rate (eGFR) within the first four years, and a reduction in eGFR without improvement in the 5th year. A generalized additive model (GAM) was used to determine the cut-off value of FGF-23 to predict RKFD.

RESULTS

The incidence of RKFD was 18.0% (114/634). After matching for age and sex at a 1:1 ratio, a total of 220 subjects were analyzed. eGFRcr-cys was negatively correlated with total vitamin D level but seemed irrelevant to FGF-23. Multivariable logistic regression analysis showed that FGF-23, eGFRcr-cys, and urine albumin-to-creatinine ratio (UACR) were independent predictors of the possibility of RKFD. FGF-23 showed the best predictive performance for RKFD (AUROC: 0.803), followed by baseline eGFRcr-cys (AUROC: 0.639) and UACR (AUROC: 0.591). From the GAM, 32 pg/mL was the most appropriate cut-off value of FGF-23 with which to predict RKFD. The subgroup and sensitivity analyses showed consistent results that high-FGF-23 subjects had higher risks of RKFD.

CONCLUSIONS

Circulating FGF-23 level could be a helpful predictor for RKFD in this community-based population.

Ureterorenoscopic (URS) Lithotripsy and Balloon Dilation Cause Acute Kidney Injury and Distal Renal Tubule Damage: A Prospective Study

Ureterorenoscopy (URS) is believed to be a safe and effective procedure for treating ureteral stones or ureteral strictures. Rapidly increasing intrarenal pressure during URS may have a negative impact on the kidney, but its effect on renal function is not well known. The aim of this study was to evaluate whether URS balloon dilation or lithotripsy could cause acute kidney injury (AKI), which was evaluated using urine neutrophil gelatinase-associated lipocalin (NGAL), and renal tubular damage, which was evaluated using urine α-glutathione S-transferase (GST) and πGST. This prospective study included 207 patients with a mean age of 53.8 years between September 2012 and June 2013. Four groups were included: the ureteral stricture group (group 1), the ureteral stone group (group 2), and two control groups. URS increased urine NGAL (uNGAL) levels on days 1 and 14 in both groups, and only elevated uGST levels were noted on day 14 after URS lithotripsy (URS). On day 14, the difference between low-grade and high-grade hydronephrosis was significant in group 1 (p < 0.001) compared to that in group 2 (p = 0.150). Multivariate logistic regression analysis revealed that age, baseline estimated glomerular filtration rate (eGFR), and stone size > 1.0 cm were associated with the complete recovery of hydronephrosis after URS on day 14. Patients with ureteral stones with preserved renal function had more AKI than those with impaired renal function. However, there was no significant difference in URS-related AKI between the ≤1 cm and >1 cm subgroups. In addition, urine αGST and πGST levels were both significantly higher in the stone > 1 cm subgroup than in the ≤1 cm subgroup. In conclusion, URS laser lithotripsy and balloon dilatation resulted in AKI and renal tubular damage on day 14, although post-URS double-J (DBJ) stenting was performed in every patient.

Application of New Acute Kidney Injury Biomarkers

Kidney-related biomarkers can provide structural and functional information about different parts of the nephron. These biomarkers can be used to evaluate glomerular, tubular, or interstitial injury, inflammation, or repair, and glomerular or tubular function. Furthermore, biomarkers can improve the acute kidney injury diagnosis in various clinical conditions, including acute interstitial nephritis, acute tubular injury, hepatorenal and cardiorenal syndrome, ischemic and nephrotoxic acute kidney injury, and drug-induced acute kidney injury. Biomarkers might be used as an additional precision medicine tool in managing patients with acute kidney injury; they can help with clinical decision-making and impact patient outcomes. In this chapter, we reviewed the utility of biomarkers used in acute kidney injury.

Distinct Subtyping of Successful Weaning from Acute Kidney Injury Requiring Renal Replacement Therapy by Consensus Clustering in Critically Ill Patients

Background: Clinical decisions regarding the appropriate timing of weaning off renal replacement therapy (RRT) in critically ill patients are complex and multifactorial. The aim of the current study was to identify which critical patients with acute kidney injury (AKI) may be more likely to be successfully weaned off RRT using consensus cluster analysis. Methods: In this study, critically ill patients who received RRT at three multicenter referral hospitals at several timepoints from August 2016 to July 2018 were enrolled. An unsupervised consensus clustering algorithm was used to identify distinct phenotypes. The outcomes of interest were the ability to wean off RTT and 90-day mortality. Results: A total of 124 patients with AKI requiring RRT (AKI-RRT) were enrolled. The 90-day mortality rate was 30.7% (38/124), and 49.2% (61/124) of the patients were successfully weaned off RRT for over 90 days. The consensus clustering algorithm identified three clusters from a total of 45 features. The three clusters had distinct features and could be separated according to the combination of urinary neutrophil gelatinase-associated lipocalin to creatinine ratio (uNGAL/Cr), Sequential Organ Failure Assessment (SOFA) score, and estimated glomerular filtration rate at the time of weaning off RRT. uNGAL/Cr (hazard ratio [HR] 2.43, 95% confidence interval [CI]: 1.36–4.33) and clustering phenotype (cluster 1 vs. 3, HR 2.7, 95% CI: 1.11–6.57; cluster 2 vs. 3, HR 44.5, 95% CI: 11.92–166.39) could predict 90-day mortality or re-dialysis. Conclusions: Almost half of the critical patients with AKI-RRT could wean off dialysis for over 90 days. Urinary NGAL/Cr and distinct clustering phenotypes could predict 90-day mortality or re-dialysis.

Angiotensin II Receptor Blocker Associated With Less Outcome Risk in Patients With Acute Kidney Disease

Objective: The aim of this study was to explore the respective use of angiotensin-converting-enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs) on the outcomes of patients who could be weaned from dialysis-requiring acute kidney injury (AKI-D). Methods: This case-control study enrolled 41,731 patients who were weaned from AKI-D for at least 7 days from Taiwan's National Health Insurance Administration. We further grouped AKI-D patients according to ACEi and ARB use to evaluate subsequent risks of all-cause mortality and re-dialysis. The outcomes included the all-cause mortality and new-onset of end-stage kidney disease (ESKD; re-dialysis) following withdraw from AKI-D. Results: A total of 17,141 (41.1%) patients surviving AKI-D could be weaned from dialysis for at least 7 days. The overall events of mortality were 366 (48.9%) in ACEi users, 659 (52.1%) in ARB users, and 6,261 (41.3%) in ACEi/ARB nonusers, during a mean follow-up period of 1.01 years after weaning from AKI-D. In regard to all-cause of mortality, pre-dialysis ARB users had lower incidence than ACEi users [hazard ratio (HR 0.82), p = 0.017]. Compared with ACEi/ARB nonusers, continuing ARB users had a significantly low risk of long-term all-cause mortality (adjusted hazard ratio 0.51, p = 0.013) after propensity score matching. However, new users of ACEi at the acute kidney disease (AKD) period had a higher risk of re-dialysis after weaning than ACEi/ARB nonusers (aHR 1.82, p < 0.001), whereas neither ACEi nor ARB users confronted significantly increased risks of hyperkalemia after weaning. Conclusions: Compared with patients without ACEi/ARB, those continuing to use ARB before the event and after weaning had low all-cause mortality, while new users of ACEi at AKD had increased risk of re-dialysis. AKI-D patients continuing to use ACEi or ARB did not have higher risk of hyperkalemia. Future prospective randomized trials are expected to confirm these findings.

Predialysis serum lactate levels could predict dialysis withdrawal in Type 1 cardiorenal syndrome patients

BACKGROUND

Renal replacement therapy (RRT) is an effective rescue therapy for Type 1 cardiorenal syndrome (CRS). Previous studies have demonstrated that type 1 CRS patients with severe renal dysfunction were susceptible to sepsis, and that serum lactate has been correlated with the risk of mortality in patients with sepsis. However, the association between serum lactate level and the prognosis of type 1 CRS patients requiring RRT is unknown.

METHODS

An inception cohort of 500 type 1 CRS patients who received RRT in a tertiary-care referral hospital in Taiwan from August 2011 to January 2018 were enrolled. The outcomes of interest were dialysis withdrawal and 90-day mortality. The results were further externally validated using sampling data of type 1 CRS patients requiring dialysis from multiple tertiary-care centers.

FINDINGS

The 90-day mortality rate was 52.8% and the incidence rate of dialysis withdrawal was 34.8%. Lower pre-dialysis lactate was correlated with a higher rate of dialysis withdrawal and lower rate of mortality. Generalized additive model showed that 4.2 mmol/L was an adequate cut-off value of lactate to predict mortality. Taking mortality as a competing risk, Fine-Gray subdistribution hazard analysis further indicated that a low lactate level (≦ 4.2 mmol/L) was an independent predictor for the possibility of dialysis withdrawal, as also shown in external validation. The interaction of quick Sequential Organ Failure Assessment score and lactate was associated with dialysis dependence in a disease severity-dependent manner. Furthermore, the associations between hyperlactatemia and dialysis dependence were consistent in the patients with and without sepsis.

INTERPRETATION

Serum lactate level is accurate and capable of forecasting the prognosis along with qSOFA severity for clinical decision-making for treating type 1 CRS patients. Further studies are needed to validate our results.

FUNDING

This study was supported by grants from Taiwan National Science Council [104-2314-B-002-125-MY3,106-2314-B-002-166-MY3,107-2314-B-002-026-MY3], National Taiwan University Hospital [106-FTN20,106-P02,UN106-014,106-S3582,107-S3809,107-T02,PC1246,VN109-09,109-S4634,UN109-041], Ministry of Science and Technology of the Republic of China [MOST106-2321-B-182-002,106-2314-B-182A-064,MOST107-2321-B-182-004,MOST107-2314-B-182A-138, MOST108-2321-B-182-003,MOST109-2321-B-182-001, MOST108-2314-B-182A-027], Chang Gung Memorial Hospital [CMRPG-2G0361,CMRPG-2H0161,CMRPG-2J0261, CMRPG-2K0091], and Ministry of Health and Welfare of the Republic of China [PMRPG-2L0011].

Angiotensin II Receptor Blockers but Not Angiotensin-Converting Enzyme Inhibitors Are Associated With a Reduced Risk of Acute Kidney Injury After Major Surgery

Objective: We investigated the respective effects of preoperative angiotensin-converting-enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) on the incidence of postoperative acute kidney injury (AKI) and mortality.

Methods: In this nested case-control study, we enrolled 20,276 patients who received major surgery. We collected their baseline demographic data, comorbidities and prescribed medication, the outcomes of postoperative AKI and mortality. AKI was defined by the criteria suggested by KDIGO (Kidney disease: Improving Global Outcome). Logistic regression was used to assess the impact of exposure to ACEIs or ARBs.

Results: Compared with patients without ACEI/ARB, patient who received ARBs had a significantly lower risk for postoperative AKI (adjusted odds ratio (OR) 0.82, p = 0.007). However, ACEI users had a higher risk for postoperative AKI than ARB users (OR 1.30, p = 0.027), whereas the risk for postoperative AKI was not significantly different between the ACEI users and patients without ACEI/ARB (OR 1.07, p = 0.49). Compared with patients without ACEI/ARB, both ACEI and ARB users were associated with a reduced risk of long-term all-cause mortality following surgery (OR 0.47, p = 0.002 and 0.60, p < 0.001 in ACEI and ARB users, respectively), without increasing the risk of hyperkalemia during the index hospitalization (p = 0.20). The risk of long-term all-cause mortality following surgery in ACEIs and ARBs users did not differ significantly (OR 0.74, p = 0.27). Furthermore, the higher the defined daily dose of ARB, the better the protection against AKI provided.

Conclusion: Our study revealed that preoperative use of ARBs was associated with reduced postoperative AKI, which is better in high quantity, whereas preoperative use of ACEIs or ARBs were both associated with reduced mortality and did not increase the risk of hyperkalemia.

Urinary sodium potassium ratio is associated with clinical success after adrenalectomy in patients with unilateral primary aldosteronism

Background

The urinary sodium potassium (NaK) ratio is associated with dietary sodium and potassium intake and blood pressure, and it also reflects the activity of aldosterone. Herein we evaluated the value of the urinary NaK ratio in predicting the surgical outcomes of patients with unilateral primary aldosteronism (uPA).

Methods

This non-concurrent prospective cohort study was conducted from 2011 to 2017 and included 241 uPA patients who had undergone adrenalectomy. Predictors of successful clinical outcomes were analyzed using logistic regression.

Results

Among the 241 uPA patients, 197 (81.7%) achieved clinical complete or partial success. A urinary sodium potassium ratio <3 (odds ratio (OR): 2.5; 95% confidence interval (CI): 1.2-5.4; p = 0.015), body mass index <25 kg/m² (OR: 2.82; 95% CI: 1.31-6.06; p = 0.008), renin <1 ng/mL/h (OR: 2.51; 95% CI: 1.01-6.21; p = 0.047) and mean preoperative blood pressure >115 mmHg (OR: 5.02; 95% CI: 2.10-11.97; p < 0.001) could predict clinical success after adrenalectomy. Furthermore, higher pre-treatment plasma aldosterone (OR: 1.014; 95% CI 1.005-1.024; p = 0.002) or lower serum potassium (OR: 0.523; 95% CI: 0.328-0.836; p = 0.007) were correlated with lower urinary NaK ratio (<3), and log urinary NaK ratio was positively correlated with serum C-reactive protein (β value 2.326; 95% CI 0.029-4.623; p = 0.047).

Conclusions

uPA patients with a lower urinary NaK ratio, due to high plasma aldosterone and low serum potassium concentrations, were more likely to have clinical success after adrenalectomy. uPA patients with a higher urinary NaK ratio were associated with more severe inflammatory status, and possibly more resistant hypertension post-operatively.

Transtubular potassium gradient predicts kidney function impairment after adrenalectomy in primary aldosteronism

Background:

In primary aldosteronism (PA), kidney function impairment could be concealed by relative hyperfiltration and emerge after adrenalectomy. We hypothesized transtubular gradient potassium gradient (TTKG), a kidney aldosterone bioactivity indicator, could correlate to end organ damage and forecast kidney function impairment after adrenalectomy.

Methods:

In the present prospective study, we enrolled lateralized PA patients who underwent adrenalectomy and were followed up 12 months after operation in the Taiwan Primary Aldosteronism Investigation (TAIPAI) registry from 2010 to 2018. The clinical outcome was kidney function impairment, defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m² at 12 months after adrenalectomy. End organ damage is determined by microalbuminuria and left ventricular mass.

Results:

In total, 323 patients [mean, 50.8 ± 10.9 years old; female 178 (55.1%)] were enrolled. Comparing pre-operation and post-operation data, systolic blood pressure, serum aldosterone, urinary albumin to creatinine ratio and eGFR decreased. TTKG ⩾ 4.9 correlated with pre-operative urinary albumin to creatinine ratio >50 mg/g [odds ratio (OR) = 2.42; p = 0.034] and left ventricular mass (B = 20.10; p = 0.018). Multivariate logistic regression analysis demonstrated that TTKG ⩾ 4.9 could predict concealed chronic kidney disease (OR = 5.42; p = 0.011) and clinical success (OR = 2.90, p = 0.017) at 12 months after adrenalectomy.

Conclusions:

TTKG could predict concealed kidney function impairment and cure of hypertension in PA patients after adrenalectomy. TTKG more than 4.9 as an adverse surrogate of aldosterone and hypokalaemia correlated with pre-operative end organ damage in terms of high proteinuria and cardiac hypertrophy.

Association between regional economic status and renal recovery of dialysis-requiring acute kidney injury among critically ill patients

The association between regional economic status and the probability of renal recovery among patients with dialysis-requiring AKI (AKI-D) is unknown. The nationwide prospective multicenter study enrolled critically ill adult patients with AKI-D in four sampled months (October 2014, along with January, April, and July 2015) in Taiwan. The regional economic status was defined by annual disposable income per capita (ADIPC) of the cities the hospitals located. Among the 1,322 enrolled patients (67.1 ± 15.5 years, 36.2% female), 833 patients (63.1%) died, and 306 (23.1%) experienced renal recovery within 90 days following discharge. We categorized all patients into high (n = 992) and low economic status groups (n = 330) by the best cut-point of ADIPC determined by the generalized additive model plot. By using the Fine and Gray competing risk regression model with mortality as a competing risk factor, we found that the independent association between regional economic status and renal recovery persisted from model 1 (no adjustment), model 2 (adjustment to basic variables), to model 3 (adjustment to basic and clinical variables; subdistribution hazard ratio, 1.422; 95% confidence interval, 1.022–1.977; p = 0.037). In conclusion, high regional economic status was an independent factor for renal recovery among critically ill patients with AKI-D.

Association of visceral adiposity and clinical outcome among patients with aldosterone producing adenoma

INTRODUCTION

Primary aldosteronism (PA) is a common form of secondary hypertension that has significant cardiovascular events and increased prevalence of metabolic syndrome and diabetics. Although plasma aldosterone concentration is positively correlated with visceral fat area (VFA) in non-PA individuals, the role of visceral adiposity associated with clinical success after surgery is not known.

RESEARCH DESIGN AND METHODS

We analyzed patients who underwent adrenalectomy for aldosterone-producing adenoma (APA) at the Taiwan PA Investigator group. VFA was calculated from the abdominal CT scan at APA diagnosis, and all patients received adrenalectomy.

RESULTS

The study involved 100 consecutive patients with APA (42 males; mean age 49.3 years) matched with 41 essential hypertension (EH) patients. Patients with APA had smaller VFA (p=0.010) than their EH counterparts. Multiple linear regression analysis revealed that the duration of hypertension (p=0.007), but not plasma aldosterone, was negatively correlated with VFA in patients with APA. Logistic regression analysis showed that log VFA (OR=0.065, p<0.001) and duration of hypertension before PA diagnosis (OR=0.919, p=0.011) can predict complete clinical success after adrenalectomy. Multifactor-adjusted generalized additive model demonstrated that log VFA <9.2 was associated with complete cure of hypertension. Furthermore, VFA was increased at 6 months after adrenalectomy (p=0.045).

CONCLUSIONS

Patients with APA had smaller VFA than their EH counterparts, and VFA increased after adrenalectomy. Clinical complete cure of hypertension after surgery was associated with smaller VFA and shorter duration of hypertension at PA diagnosis, suggesting a potential interplay of visceral adiposity and aldosterone of the patients with APA.

Acute Kidney Injury and Septic Shock-Defined by Updated Sepsis-3 Criteria in Critically Ill Patients

Sepsis is commonly associated with acute kidney injury (AKI), particularly in those requiring dialysis (AKI-D). To date, Sepsis-3 criteria have not been applied to AKI-D patients. We investigated sepsis prevalence defined by Sepsis-3 criteria and evaluated the outcomes of septic-associated AKI-D among critically ill patients. Using the data collected from a prospective multi-center observational study, we applied the Sepsis-3 criteria to critically ill AKI-D patients treated in intensive care units (ICUs) in 30 hospitals between September 2014 and December 2015. We described the prevalence, outcomes, and characteristics of sepsis as defined by the screening Sepsis-3 criteria among AKI-D patients, and compared the outcomes of AKI-D patients with or without sepsis using the Sepsis-3 criteria. A total of 1078 patients (median 70 years; 673 (62.4%) men) with AKI-D were analyzed. The main etiology of AKI was sepsis (71.43%) and the most frequent indication for acute dialysis was oliguria (64.4%). A total of 577 (53.3% of 1078 patients) met the Sepsis-3 criteria, and 206 among the 577 patients (19.1%) had septic shock. Having sepsis and septic shock were independently associated with 90-day mortality among these ICU AKI-D patients (hazard ratio (HR) 1.23 (p = 0.027) and 1.39 (p = 0.004), respectively). Taking mortality as a competing risk factor, AKI-D patients with septic shock had a significantly reduced chance of weaning from dialysis at 90 days than those without sepsis (HR 0.65, p = 0.026). The combination of the Sepsis-3 criteria with the AKI risk score led to better performance in forecasting 90-day mortality. Sepsis affects more than 50% of ICU AKI patients requiring dialysis, and one-fifth of these patients had septic shock. In AKI-D patients, coexistent with or induced by sepsis (as screened by the Sepsis-3 criteria), there is a significantly higher mortality and reduced chance of recovering sufficient renal function, when compared to those without sepsis.

Plasma Aldosterone After Seated Saline Infusion Test Outperforms Captopril Test at Predicting Clinical Outcomes After Adrenalectomy for Primary Aldosteronism

OBJECTIVE

The saline infusion test (SIT) and the captopril test (CT) are widely used as confirmatory tests for primary aldosteronism (PA). We hypothesized that post-SIT and post-CT plasma aldosterone concentrations (PAC) indicate the severity of aldosterone-producing adenoma (APA) and might predict clinical outcome.

METHODS

We recruited 216 patients with APA in the Taiwan Primary Aldosteronism Investigation (TAIPAI) registry who received both seated SIT and CT as confirmatory tests. The data of 143 patients who underwent adrenalectomy with complete follow-up after diagnosis were included in the final analysis. We determined the proportion of patients achieving clinical success in accordance with the Primary Aldosteronism Surgical Outcome consensus. Logistic regression analysis was conducted to identify preoperative factors associated with cure of hypertension.

RESULTS

Complete clinical success was achieved in 48 (33.6%) patients and partial clinical success in 59 (41.2%) patients; absent clinical success was seen in 36 (25.2%) of 143 patients. Post-SIT PAC but not post-CT PAC was independently associated with clinical outcome. Higher levels of post-SIT PAC had a higher likelihood of clinical benefit (complete plus partial clinical success; odds ratio = 1.04 per ng/dl increase, 95% confidence interval = 1.01, 1.06; P = 0.004). Patients with post-SIT PAC > 25 ng/dl were more likely to have a favorable clinical outcome after adrenalectomy. This cutoff value translated into a positive predictive value of 86.0%.

CONCLUSIONS

We suggest that post-SIT PAC is a better predictor than post-CT PAC for clinical success in PA post adrenalectomy.

Biochemical evaluation of kidney disease

Different biochemical markers exist in both blood and urine for assessing renal function. Most of these biomarkers have advantages and limitations associated with their use, which is important to consider when ordering and utilising them in the clinical setting. The ideal marker should be able to detect acute kidney injury (AKI) at the onset and be used for the diagnosis and ongoing monitoring and management of kidney disease. The search for such a marker is ongoing, as all potential candidates thus far are associated with certain limitations. This article will attempt to compare and contrast established and emerging kidney disease markers.

Proteomics and Metabolomics for AKI Diagnosis

Acute kidney injury (AKI) is a severe and frequent condition in hospitalized patients. Currently, no efficient therapy of AKI is available. Therefore, efforts focus on early prevention and potentially early initiation of renal replacement therapy to improve the outcome in AKI. The detection of AKI in hospitalized patients implies the need for early, accurate, robust, and easily accessible biomarkers of AKI evolution and outcome prediction because only a narrow window exists to implement the earlier-described measures. Even more challenging is the multifactorial origin of AKI and the fact that the changes of molecular expression induced by AKI are difficult to distinguish from those of the diseases associated or causing AKI as shock or sepsis. During the past decade, a considerable number of protein biomarkers for AKI have been described and we expect from recent advances in the field of omics technologies that this number will increase further in the future and be extended to other sorts of biomolecules, such as RNAs, lipids, and metabolites. However, most of these biomarkers are poorly defined by their AKI-associated molecular context. In this review, we describe the state-of-the-art tissue and biofluid proteomic and metabolomic technologies and new bioinformatics approaches for proteomic and metabolomic pathway and molecular interaction analysis. In the second part of the review, we focus on AKI-associated proteomic and metabolomic biomarkers and briefly outline their pathophysiological context in AKI.

Plasma Aldosterone Concentration as a Determinant for Statin Use among Middle-Aged Hypertensive Patients for Atherosclerotic Cardiovascular Disease

The use of statin therapy on the prevention of atherosclerotic cardiovascular disease (ASCVD) is recommended by the American College of Cardiology (ACC) and the American Heart Association (AHA); nevertheless, its validation on primary aldosteronism (PA) patients has not been reported. We investigated the risk of incident ASCVD in middle-aged patients with PA compared with essential hypertension (EH) based on ACC/AHA recommendations. We enrolled 461 PA patients and 553 EH patients. Even though the ratio of metabolic syndrome in each group was similar, the PA group had higher systolic blood pressures, higher low-density lipoprotein levels, higher plasma aldosterone concentration (PAC), lower high-density lipoprotein levels, and higher 10-year ASCVD compared to the EH group. The discriminative power for predicting ASCVD by the recommended statin use from the ACC/AHA guidelines was proper in the PA group (i.e., under the receiver operating characteristic curve (95% confidence interval; 0.94 (0.91–0.96)). The generalized additive model showed patients with PAC higher than 60 ng/dL accompanying the standard timing of the statin use suggested by the ACC/AHA. The ACC/AHA guidelines have good discriminative power in the prediction of middle-aged high-risk hypertensive patients, while PAC identifies those high-risk individuals who may benefit from early statin therapy.

Biomarkers in acute kidney injury (AKI)

Acute kidney injury is common in critically ill patients and portends a significant impact on mortality, progressive chronic kidney disease, and cardiovascular disease and mortality. Though most physicians alter therapy depending on changes in serum creatinine, this often represents delayed intervention. Various AKI biomarkers have been discovered and validated to improve timely detection, differentiation and stratification into risk groups for progressive renal decline, need for renal replacement therapy or death. This chapter will review AKI biomarkers validated over the past decade. We also describe the clinical performance of the biomarkers. We suggest that using AKI biomarkers to complement serum creatinine (or cystatin C) and urine output will better integrate patient care through earlier recognition and clinical outcome prediction after AKI.

Serum glutathione S-transferase Pi as predictor of the outcome and acute kidney injury in premature newborns

BACKGROUND

The incidence of acute kidney injury (AKI) among the neonates treated at the Neonatal Intensive Care Unit is high with high mortality rates. Glutathione S-transferase (GST) class Pi plays an important role in the protection of cells from cytotoxic and oncogenic agents. The aim of the study was to examine whether the levels of serum glutathione S-transferase Pi (GST Pi) determined after birth have any predictive value for the outcome and development of AKI in premature neonates.

METHODS

The prospective study included 36 premature neonates. The data about morbidity was gathered for all the neonates included in the study. The blood samples were taken in the first 6 h of life and GST Pi levels were measured.

RESULTS

The mean values and standard deviations of GST Pi among the neonates who died and who survived were 1.904 ± 0.4535 vs 1.434 ± 0.444 ng/ml (p = 0.0128). Logistic regression revealed a statistically significant, positive correlation between GST Pi levels and death (p = 0.0180, OR7.5954; CI 1.4148-40.7748).The mean value of GST Pi levels in the neonates with AKI was higher than in neonates without AKI (p = 0.011).

CONCLUSIONS

The conclusion of our study is that high levels of serum GST Pi in the first 6 h after birth are associated with an increased mortality and development of AKI in prematurely born neonates.

Urinary biomarkers predict advanced acute kidney injury after cardiovascular surgery

BACKGROUND

Acute kidney injury (AKI) after cardiovascular surgery is a serious complication. Little is known about the ability of novel biomarkers in combination with clinical risk scores for prediction of advanced AKI.

METHODS

In this prospectively conducted multicenter study, urine samples were collected from 149 adults at 0, 3, 6, 12 and 24 h after cardiovascular surgery. We measured urinary hemojuvelin (uHJV), kidney injury molecule-1 (uKIM-1), neutrophil gelatinase-associated lipocalin (uNGAL), α-glutathione S-transferase (uα-GST) and π-glutathione S-transferase (uπ-GST). The primary outcome was advanced AKI, under the definition of Kidney Disease: Improving Global Outcomes (KDIGO) stage 2, 3 and composite outcomes were KDIGO stage 2, 3 or 90-day mortality after hospital discharge.

RESULTS

Patients with advanced AKI had significantly higher levels of uHJV and uKIM-1 at 3, 6 and 12 h after surgery. When normalized by urinary creatinine level, uKIM-1 in combination with uHJV at 3 h post-surgery had a high predictive ability for advanced AKI and composite outcome (AUC = 0.898 and 0.905, respectively). The combination of this biomarker panel (normalized uKIM-1, uHJV at 3 h post-operation) and Liano's score was superior in predicting advanced AKI (AUC = 0.931, category-free net reclassification improvement of 1.149, and p <  0.001).

CONCLUSIONS

When added to Liano's score, normalized uHJV and uKIM-1 levels at 3 h after cardiovascular surgery enhanced the identification of patients at higher risk of progression to advanced AKI and composite outcomes.

Hypoxic renal injury in newborns with abdominal compartment syndrome (clinical and experimental study)

BackgroundSurgical treatment for gastroschisis and congenital diaphragmatic hernia (CDH) commonly leads to abdominal compartment syndrome (ACS) associated with hypoxic renal injury. We hypothesized that measurement of urinary and serum concentrations of vascular endothelial growth factor (VEGF), π-glutathione S-transferase (π-GST), and monocyte chemoattractant protein-1 (MCP-1) may serve for noninvasive detection of hypoxic renal injury in such patients.MethodsIntra-abdominal pressure (IAP), renal excretory function, and the biomarker levels were analyzed before, 4, and 10 days after surgery. Association between the biomarker levels and renal histology was investigated using an original model of ACS in newborn rats.ResultsFour days after surgery, IAP increased, renal excretory function decreased, and the levels of VEGF, π-GST, and MCP-1 increased, indicating renal injury. Ten days after surgery, IAP partially decreased, renal excretory function completely restored, but the biomarker levels remained elevated, suggesting the ongoing kidney injury. In the model of ACS, increase in the biomarker levels was associated with progressing kidney morphological alteration.ConclusionSurgical treatment for gastroschisis and CDH is associated with prolonged hypoxic kidney injury despite complete restoration of renal excretory function. Follow-up measurement of VEGF, π-GST, and MCP-1 levels may provide a better tool for noninvasive assessment of renal parenchyma in newborns with ACS.

Hemojuvelin Predicts Acute Kidney Injury and Poor Outcomes Following Cardiac Surgery

Acute kidney injury (AKI) is detrimental after cardiac surgery. In this multicenter study, the novel biomarker hemojuvelin (HJV) was evaluated for AKI prediction following cardiac surgery. Urinary HJV, neutrophil gelatinase-associated lipocalin (NGAL), and urinary creatinine were measured in 151 patients after surgery. The outcomes of advanced AKI (KDIGO stages 2 and 3) and all causes of in-hospital mortality as the composite outcome were recorded. Areas under the receiver operator characteristic curves (AUC) and a multivariate generalized additive model (GAM) were applied to predict these outcomes of interest. Urinary HJV differentiated patients with/without AKI, advanced AKI or composite outcome after surgery (p < 0.001, by a generalized estimating equation) in this study. At three hours post-surgery, urinary HJV predicted advanced AKI (p < 0.001) and composite outcome (p < 0.001) with corresponding AUC values of 0.768 and 0.828, respectively. The performance of creatinine-adjusted HJV was also superior to NGAL in predicting advanced AKI (AUC = 0.784 and 0.694; p = 0.037) and composite outcome (AUC = 0.842 and 0.676; p = 0.002). The integration of HJV into the Cleveland Clinic score for advanced AKI led to a significant increase in risk stratification (net reclassification improvement [NRI] = 0.598; p < 0.001).

Partial purification and characterization of glutathione S-transferase from the somatic tissue of Gastrothylax crumenifer (Trematoda: Digenea)

AIM

Aim of the present study was to carry out the partial purification and biochemical characterization of glutathione S-transferase (GST) from the somatic tissue of ruminal amphistome parasite, Gastrothylax crumenifer (Gc) infecting Indian water buffalo (Bubalus bubalis).

MATERIALS AND METHODS

The crude somatic homogenate of Gc was subjected to progressive ammonium sulfate precipitation followed by size exclusion chromatography in a Sephacryl S 100-HR column. The partially purified GST was assayed spectrophotometrically, and the corresponding enzyme activity was also recorded in polyacrylamide gel. GST isolated from the amphistome parasite was also exposed to variable changes in temperature and the pH gradient of the assay mixture.

RESULTS

The precipitated amphistome GST molecules showed maximum activity in the sixth elution fraction. The GST subunit appeared as a single band in the reducing polyacrylamide gel electrophoresis with an apparent molecular weight of 26 kDa. The GST proteins were found to be fairly stable up to 37°C, beyond this the activity got heavily impaired. Further, the GST obtained showed a pH optima of 7.5.

CONCLUSION

Present findings showed that GST from Gc could be conveniently purified using gel filtration chromatography. The purified enzyme showed maximum stability and activity at 4°C.

Group analysis identifies differentially elevated biomarkers with distinct outcomes for advanced acute kidney injury in cardiac surgery

AIM

To investigate early postoperative biomarkers for risk discrimination of advanced acute kidney injury (AKI).

MATERIALS & METHODS

Postoperative plasma biomarkers including NGAL, h-FABP, CK-MB, hsTNT, NT-proBNP, IL-6, IL-10 and VEGF were analyzed using group-based method among 426 patients with AKI after cardiac surgery.

RESULTS

Six patient groups with distinct biomarker patterns were identified. Individual biomarker displayed significant difference across the groups. The groups showed better discrimination for advanced AKI than any single biomarker either with or without adjusting for clinical variables. Average concentration of a single biomarker within each group, mortality and risk of a secondary outcome all demonstrated an approximately U-shaped relationship with proportion of advanced AKI within each group.

CONCLUSION

The group-based analysis revealed that the order of the patient groups with an increasing likelihood of advanced AKI had a nonlinear relationship with average concentration of an individual biomarker, mortality and risk of other outcomes.

Predicting acute kidney injury: current status and future challenges

Acute kidney injury (AKI) is characterized by an acute decline in renal function and is associated to increased mortality rate, hospitalization time, and total health-related costs. The severity of this ‘fearsome’ clinical complication might depend on, or even be worsened by, the late detection of AKI, when the diagnosis is based on the elevation of serum creatinine (SCr). For these reasons, in recent years a great number of new tools, biomarkers and predictive models have been proposed to clinicians in order to improve diagnosis and prevent the development of AKI. The purpose of this narrative paper is to review the current state of the art in prediction and early detection of AKI and outline future challenges.

Meglitinides increase the risk of hypoglycemia in diabetic patients with advanced chronic kidney disease: a nationwide, population-based study

The safety of short-acting meglitinides in diabetic patients with advanced chronic kidney disease (CKD) has not been widely reported. Diabetic patients with advanced CKD who had a serum creatinine level of > 6 mg/dL a hematocrit level of ≦ 28% and received erythropoiesis-stimulating agent treatment between 2000 and 2010, were included in this nationwide study in Taiwan. The outcomes of interest were defined as hypoglycemia and long-term mortality. The risks of hypoglycemia and death were analyzed using Cox proportional hazards models, with end-stage renal disease and anti-diabetic drugs as time-dependent variables. Fresh users and matched non-users of meglitinides (both n = 2,793) were analyzed. The use of meglitinides increased the risk of hypoglycemia (HR, 1.94, p<0.001), as did other anti-diabetic agents. Concomitant use of meglitinide and insuilin will incresase the hypoglycemic risk. (HR, 1.69, p=0.018) Moreover, it was not the use of meglitinides, but the presence of hypoglycemia that predicted mortality. The function curve showed an insignificant trend towards increased hypoglycemic risk in patients aged > 62 and ≤ 33 years from the generalized additive model. This study suggests that the use of short-acting meglitinides could be associated with increased risk of hypoglycemia in diabetic patients with advanced CKD, especially in patients aged > 62 and ≤ 33 years. Meglitinide combined with insulin will increase hypoglycemia in patients with advanced CKD.

Nephroprotective Effects of N-Acetylcysteine Amide against Contrast-Induced Nephropathy through Upregulating Thioredoxin-1, Inhibiting ASK1/p38MAPK Pathway, and Suppressing Oxidative Stress and Apoptosis in Rats

Contrast-induced nephropathy (CIN) is a leading cause of hospital-acquired acute kidney injury (AKI) due to apoptosis induced in renal tubular cells. Our previous study demonstrated the novel N-acetylcysteine amide (NACA); the amide form of N-acetyl cysteine (NAC) prevented renal tubular cells from contrast-induced apoptosis through inhibiting p38 MAPK pathway in vitro. In the present study, we aimed to compare the efficacies of NACA and NAC in preventing CIN in a well-established rat model and investigate whether thioredoxin-1 (Trx1) and apoptosis signal-regulating kinase 1 (ASK1) act as the potential activator for p38 MAPK. NACA significantly attenuated elevations of serum creatinine, blood urea nitrogen, and biomarkers of AKI. At equimolar concentration, NACA was more effective than NAC in reducing histological changes of renal tubular injuries. NACA attenuated activation of p38 MAPK signal, reduced oxidative stress, and diminished apoptosis. Furthermore, we demonstrated that contrast exposure resulted in Trx1 downregulation and increased ASK1/p38 MAPK phosphorylation, which could be reversed by NACA and NAC. To our knowledge, this is the first report that Trx1 and ASK1 are involved in CIN. Our study highlights a renal protective role of NACA against CIN through modulating Trx1 and ASK1/p38 MAPK pathway to result in the inhibition of apoptosis among renal cells.