METTL3-Mediated N6-methyladenosine mRNA Modification and cGAS-STING Pathway Activity in Kidney Fibrosis.

BACKGROUND: Chemical modifications on RNA profoundly impact RNA function and regulation. m6A, the most abundant RNA modification in eukaryotes, plays a pivotal role in diverse cellular processes and disease mechanisms. However, its importance is understudied in human chronic kidney disease (CKD) samples regarding its influence on pathological mechanisms. METHODS: LC-MS/MS and Methylated RNA Immunoprecipitation (MeRIP) sequencing were utilized to examine alterations in m6A levels and patterns in CKD samples. Overexpression of the m6A writer METTL3 in cultured kidney tubular cells was performed to confirm the impact of m6A in tubular cells and explore the biological functions of m6A modification on target genes. Additionally, tubule-specific deletion of Mettl3 (Ksp-Cre Mettl3f/f) mice and the use of anti-sense oligonucleotides inhibiting Mettl3 expression were utilized to reduce m6A modification in an animal kidney disease model. RESULTS: By examining 127 human CKD samples, we observed a significant increase in m6A modification and METTL3 expression in diseased kidneys. Epitranscriptomic analysis unveiled an enrichment of m6A modifications in transcripts associated with the activation of inflammatory signaling pathways, particularly the cGAS-STING pathway. m6A hypermethylation increased mRNA stability in cGAS and STING1, as well as elevated the expression of key proteins within the cGAS-STING pathway. Both the tubule-specific deletion of Mettl3 and the use of anti-sense oligonucleotides to inhibit Mettl3 expression protected mice from inflammation, reduced cytokine expression, decreased immune cell recruitment, and attenuated kidney fibrosis. CONCLUSIONS: Our research revealed heightened METTL3-mediated m6A modification in fibrotic kidneys, particularly enriching the cGAS-STING pathway. This hypermethylation increased mRNA stability for cGAS and STING1, leading to sterile inflammation and fibrosis.

Association between Premorbid Renin-Angiotensin-Aldosterone System Blockade and the Risk of Acute Kidney Injury in Critically Ill Patients.

Background: Angiotensin-converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) are commonly used for hypertension and cardiovascular diseases. However, whether their use increases the risk of acute kidney injury (AKI) and should be discontinued during acute illness remains controversial. Methods: This retrospective study enrolled 952 dialysis-free patients who were admitted to intensive care units (ICUs) between 2015 and 2017, including 476 premorbid long-term (> 1 month) ACEi/ARB users. Propensity score matching was performed to adjust for age, gender, comorbidities, and disease severity. The primary endpoint was the occurrence of AKI during hospitalization, and the secondary endpoint was mortality or dialysis within 1 year. Results: Compared with non-users, the ACEi/ARB users were not associated with an increased AKI risk during hospitalization [66.8% vs. 70.4%; hazard ratio (HR): 1.13, 95% confidence interval (CI): 0.97-1.32, p = 0.126]. However, the ACEi/ARB users with sepsis (HR: 1.29, 95% CI: 1.04-1.60, p = 0.021) or hypotension (HR: 1.21, 95% CI: 1.02-1.14, p = 0.034) were found to have an increased AKI risk in subgroup analysis. Nevertheless, compared with the non-users, the ACEi/ARB users were associated with a lower incidence of mortality or dialysis within 1 year (log-rank p = 0.011). Conclusions: Premorbid ACEi/ARB usage did not increase the incidence of AKI, and was associated with a lower 1-year mortality and dialysis rate in patients admitted to ICUs. Regarding the results of subgroup analysis, renin-angiotensin-aldosterone system blockade may still be safe and beneficial in the absence of sepsis or circulation failure. Further large-scale studies are needed to confirm our findings.

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH4I.

The electrochemical preparation of 2-aminothiazoles has been achieved by the reaction of active methylene ketones with thioureas assisted by ᴅʟ-alanine using NH4I as a redox mediator. The electrochemical protocol proceeds in an undivided cell equipped with graphite plate electrodes under constant current conditions. Various active methylene ketones, including ß-keto ester, ß-keto amide, ß-keto nitrile, ß-keto sulfone and 1,3-diketones, can be converted to the corresponding 2-aminothiazoles. Mechanistically, the in situ generated α-iodoketone was proposed to be the key active species.

Clinical Significance of Bioimpedance Spectroscopy in Critically Ill Patients.

BACKGROUND: Early fluid resuscitation is a key aspect in the successful management of critically ill patients, but the optimal goal for volume control after the acute stage of critical illness remains unclear. This study aimed to evaluate the prognostic value of bioimpedance spectrometry for fluid management in critically ill patients. METHODS: In this prospective observational study, patients who consented to participate were screened within the first 24 hours of admission to a medical intensive care unit (ICU) from February 4, 2015, to January 31, 2016. Information on demographics, comorbidities, primary reasons for admission, baseline laboratory data, and ventilator or inotropic use were documented. Data of fluid intake, fluid output, and body weight were recorded for the first 3 days of ICU admission. Bioimpedance spectrometry was performed on the first and third days after ICU admission. All participants were followed until death or hospital discharge. RESULTS: Of the 140 enrolled patients (median age: 70 years, interquartile range: 60-77 years), 23 (16.4%) patients died during hospitalization. Independent predictors of hospital mortality were Acute Physiology and Chronic Health Evaluation II scores (per 1 point increase, odds ratio [OR]: 1.101) and overhydration (OH) volume on the first day (per 1 L increase, OR: 1.216). Compared to normal OH status (OH volume between -1 and 1 L), hyper OH status (OH volume < -1 L) on the third day after ICU admission was an independent predictor of hospital death (OR: 7.609). Normal OH status on the third day was associated with greater numbers of ICU-free and ventilator-free days. CONCLUSION: Bioimpedance spectrometry can be used to predict outcomes in critically ill patients. Increased OH volume on day 1 and hyper OH volume on day 3 of ICU admission are associated with a greater risk of hospital mortality. Volume status on day 3 is associated with durations of ventilator use and ICU stay.

A patient with hemodialysis-related hyperammonemic encephalopathy: a delayed presentation of congenital arterioportal fistulas.

We present a 32-year-old woman who developed hyperammonemic encephalopathy during hemodialysis. She was rather well before 2009 when receiving peritoneal dialysis due to chronic interstitial nephritis. Due to a refractory peritonitis, the treatment was shifted to hemodialysis in January 2009. About 1 year later, she was found with consciousness disturbance during hemodialysis then admitted to the hospital because of hyperammonemia (165 µg/dl). During hospitalization, the patient's abdominal Doppler sonography showed a hepatofugal flow in the portal trunk while the hepatic artery angiography demonstrated multiple intrahepatic arterioportal fistulas. Her general condition was improved after the treatment of lactulose and hepatic artery embolization. With the occurrence of arterioportal fistulas induced portal hypertension, we speculated that the portal-systemic shunt was enhanced during hemodialysis because of venous hypotension which then resulted in the transient hyperammonemia. To the best of our knowledge, this is the first patient who developed hemodialysis- related hyperammonemic encephalopathy due to multiple arterioportal fistulas.

Chronic Kidney Disease Is Associated With Increased Cardiac Corin Expression But Decreased Proatrial Natriuretic Peptide Conversion Activity.

Background Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular disease. Corin converts proatrial natriuretic peptide into its active form after being activated by PCSK6 (proprotein convertase subtilisin/kexin type 6) protease. It remains unknown whether the PCSK6/corin/atrial natriuretic peptide pathway plays a role in CKD-induced cardiomyopathy. Methods and Results Serum corin, left ventricular mass index, and corin-left ventricular mass index correlation were compared between outpatients with versus without CKD. Cardiac corin expression and activity as well as serum corin were compared between 5/6 nephrectomy CKD animal models and sham controls. The effects of indoxyl sulfate, a uremic toxin, on cardiomyocytes were examined in vitro in H9c2 cells. A total of 543 patients were enrolled in this study. Serum corin levels were elevated in patients with CKD compared with levels in patients without CKD. Serum corin levels correlated negatively with left ventricular mass index in participants without CKD, but not in patients with CKD. Compared with sham controls, CKD mice had higher serum corin levels and increased cardiac expression of corin but reduced cardiac corin conversion activity. Indoxyl sulfate stimulated corin expression while suppressing serine protease activity in H9c2 cardiomyoblasts. Lower PCSK6 expression in CKD mouse hearts and indoxyl sulfate-treated H9c2 cardiomyoblasts may explain, at least partly, the observed CKD-associated reduction in corin activity. Conclusions In CKD, cardiac and serum levels of corin are increased, yet corin activity is suppressed. The latter may be attributable to reduced PCSK6 expression. These findings suggest that corin dysfunction may play a significant role in the pathogenesis of CKD-associated cardiomyopathy.

Sacubitril/Valsartan in Patients With Heart Failure and Concomitant End-Stage Kidney Disease.

Background Heart failure with reduced ejection fraction (HFrEF) is a chronic disease with substantial mortality. Management of HFrEF has seen significant breakthrough after the launch of neprilysin inhibitor. The PARADIGM-HF (Prospective Comparison of ARNI with ACEI to Determine Impacton Global Mortality and Morbidity in Heart Failure) trial showed that sacubitril/valsartan significantly reduces HFrEF mortality and the heart failure hospitalization rate. However, in patients with advanced kidney disease, who have the highest prevalence of heart failure, the efficacy and safety of sacubitril/valsartan remains uncertain. We aim to study the efficiency of sacubitril/valsartan in patients with end-stage kidney disease. Methods and Results Heart function was screened by echocardiogram among all patients with end-stage kidney disease in 2 hospitals. Patients with HFrEF received either sacubitril/valsartan or conventional treatment. Fifteen echocardiographic parameters were compared before and after treatment. After 1-year sacubitril/valsartan treatment, parameters of systolic (left ventricular ejection fraction 31.3% to 45.1%, P<0.0001; left ventricular end-systolic volume 95.7 to 70.1 mL, P=0.006; left ventricular internal diameter at end-systole phase 47.2 to 40.1 mm, P=0.005), and diastolic (E/A ratio 1.3 to 0.8, P=0.009; E/Med e' ratio 25.3 to 18.8, P=0.010) function improved in patients with HFrEF and end-stage kidney disease. These parameters were unchanged in the conventional treatment group. Serum potassium did not increase in the sacubitril/valsartan group. Conclusions Sacubitril/valsartan improves left ventricular systolic and diastolic function in patients with HFrEF and end-stage kidney disease.

Elevated serum galectin-1 concentrations are associated with increased risks of mortality and acute kidney injury in critically ill patients.

BACKGROUND: Galectin-1 (Gal-1), a member of the ß-galactoside binding protein family, is associated with inflammation and chronic kidney disease. However, the effect of Gal-1 on mortality and acute kidney injury (AKI) in critically-ill patients remain unclear. METHODS: From May 2018 to March 2020, 350 patients admitted to the medical intensive care unit (ICU) of Taipei Veterans General Hospital, a tertiary medical center, were enrolled in this study. Forty-one patients receiving long-term renal replacement therapy were excluded. Serum Gal-1 levels were determined within 24 h of ICU admission. The patients were divided into tertiles according to their serum Gal-1 levels (low, serum Gal-1 < 39 ng/ml; median, 39-70 ng/ml; high, ≥71 ng/ml). All patients were followed for 90 days or until death. RESULTS: Mortality in the ICU and at 90 days was greater among patients with elevated serum Gal-1 levels. In analyses adjusted for the body mass index, malignancy, sepsis, Sequential Organ Failure Assessment (SOFA) score, and serum lactate level, the serum Gal-1 level remained an independent predictor of 90-day mortality [median vs. low: adjusted hazard ratio (aHR) 2.11, 95% confidence interval (CI) 1.24-3.60, p = 0.006; high vs. low: aHR 3.21, 95% CI 1.90-5.42, p < 0.001]. Higher serum Gal-1 levels were also associated with a higher incidence of AKI within 48 h after ICU admission, independent of the SOFA score and renal function (median vs. low: aHR 2.77, 95% CI 1.21-6.34, p = 0.016; high vs. low: aHR 2.88, 95% CI 1.20-6.88, p = 0.017). The results were consistent among different subgroups with high and low Gal-1 levels. CONCLUSION: Serum Gal-1 elevation at the time of ICU admission were associated with an increased risk of mortality at 90 days, and an increased incidence of AKI within 48 h after ICU admission.

Serum PCSK6 and corin levels are not associated with cardiovascular outcomes in patients undergoing coronary angiography.

INTRODUCTION: Proprotein convertase subtilisin/kexin-6 (PCSK6) is a secretory protein that activates corin in the heart. Higher circulating levels of corin are associated with improved cardiovascular outcomes in patients with acute myocardial infarction. This study aimed to determine the role of serum PCSK6 and corin levels in predicting cardiovascular outcomes in patients with suspected coronary artery disease (CAD). MATERIALS AND METHODS: In total, 565 patients who had undergone coronary angiography were enrolled. Serum PCSK6 and corin levels were determined before the administration of contrast media. In this study, coronary revascularization, acute myocardial infarction, acute stroke, and death were defined as cardiovascular outcomes. All patients were followed up for at least one year after coronary angiography or until the occurrence of death. RESULTS: During a median follow-up of 691 days, 67 patients (15.7%) developed composite cardiovascular outcomes after coronary angiography, including 51 incidents of coronary revascularization, 7 instances of acute myocardial infarction, 2 acute strokes, and 15 deaths. After adjustment for demographic characteristics and all significant variables in the univariate analysis, serum levels of neither PCSK6 nor corin were associated with increased risk for cardiovascular outcomes. This correlation remained insignificant in patients with underlying hypertension, diabetes mellitus, CAD, heart failure, or chronic kidney disease (CKD). However, in patients without CKD, higher serum PCSK6 levels were associated with increased risk for cardiovascular outcomes (hazard ratio 1.380; 95% confidence interval 1.023-1.862). CONCLUSIONS: We found no association between cardiovascular outcomes and pre-procedural serum levels of PCSK6 or corin in patients undergoing coronary angiography. However, an increased risk was seen in non-CKD patients with higher PCSK6 levels. Further studies are needed to verify these results.

Serum Corin Level Is Associated With Subsequent Decline in Renal Function in Patients With Suspected Coronary Artery Disease.

BACKGROUND: Higher circulatory corin in patients with cardiac diseases is associated with improved cardiovascular outcomes, and chronic cardiac dysfunction is a well-known cause of progressive renal dysfunction. This study aimed to determine the role of serum corin in predicting short-term and long-term renal outcomes after contrast exposure in patients with suspected coronary artery disease. METHODS AND RESULTS: Four hundred one patients who had received coronary angiography were enrolled. Serum corin levels were determined before administration of contrast media. Contrast-induced nephropathy was defined as a rise in serum creatinine of 0.5 mg/dL or a 25% increase from baseline within 48 hours after the procedure. Progressive renal dysfunction was defined as >50% decrease in estimated glomerular filtration rate after discharge. All patients were followed up for at least 1 year or until the occurrence of death after coronary angiography. Overall, contrast-induced nephropathy occurred in 23 (5.7%) patients. During a median follow-up of 529 days, 44 (11.0%) cases had subsequent decline in renal function. After adjustment for demographic characteristics, kidney function, traditional risk factors, and medications, lower corin level was found to be independently associated with higher risk for progressive renal dysfunction (hazard ratio, 0.23; 95% confidence interval, 0.12-0.44) but not for contrast-induced nephropathy. This inverse correlation remained evident in patients with underlying chronic kidney disease, coronary artery disease, or heart failure. CONCLUSIONS: Lower baseline serum corin was associated with higher risk of renal function decline in patients undergoing coronary angiography. Further studies are needed to verify these results.

The risk factors and the impact of hernia development on technique survival in peritoneal dialysis patients: a population-based cohort study.

OBJECTIVES: There is a lack of consensus on the risk factors for hernia formation, and the impact on peritoneal dialysis (PD) survival has seldom been studied. METHODS: This was a population-based study and all collected data were retrieved from the National Health Insurance Research Database of Taiwan. Patients who commenced PD between January 1998 and December 2006 were screened for inclusion. Multiple logistic regression and Cox proportional hazards models were applied to estimate the predictors for hernia formation and determine the predictors of PD withdrawal. RESULTS: A total of 6,928 PD patients were enrolled and followed until December 2009, with 631 hernia events and 391 hernioplasties being registered in 530 patients (7.7%). The incidence rate was 0.04 hernias/patient/year. Longer PD duration (per 1 month increase, hazard ratio (HR) 1.019) and history of mitral valve prolapse (MVP) (HR 1.584) were independent risk factors for hernia formation during PD, and female gender (HR 0.617) was a protective factor. On the other hand, there were 4,468 PD withdrawals, with cumulative incidence rates of 41% at 1 year, 66% at 3 years, and 82% at 5 years. Independent determinants for cumulative PD withdrawal included hernia formation during PD (HR 1.154), age (per 1 year increase, HR 1.014), larger dialysate volume (per 1 liter increase, HR 0.496), female gender (HR 0.763), heart failure (HR 1.092), hypertension (HR 1.207), myocardial infarction (HR 1.292), chronic obstructive pulmonary disease (COPD) (HR 1.227), cerebrovascular accident (CVA) (HR 1.364), and history of MVP (HR 0.712) CONCLUSIONS: Prolonged PD duration was a risk factor for hernia formation, and female gender was protective. Hernia formation during PD therapy may increase the risk of PD withdrawal.