Impaired microvascular insulin-dependent dilation in women with a history of gestational diabetes.

Women with a history of gestational diabetes mellitus (GDM) have a significantly greater lifetime risk of developing cardiovascular disease and type 2 diabetes compared with women who had an uncomplicated pregnancy (HC). Microvascular endothelial dysfunction, mediated via reduced nitric oxide (NO)-dependent dilation secondary to increases in oxidative stress, persists after pregnancy complicated by GDM. We examined whether this microvascular dysfunction reduces insulin-mediated vascular responses in women with a history of GDM. We assessed in vivo microvascular endothelium-dependent vasodilator function by measuring cutaneous vascular conductance responses to graded infusions of acetylcholine (10-10-10-1 M) and insulin (10-8-10-4 M) in control sites and sites treated with 15 mM l-NAME [NG-nitro-l-arginine methyl ester; NO-synthase (NOS) inhibitor] or 5 mM l-ascorbate. We also measured protein expression of total endothelial NOS (eNOS), insulin-mediated eNOS phosphorylation, and endothelial nitrotyrosine in isolated endothelial cells from GDM and HC. Women with a history of GDM had reduced acetylcholine (P < 0.001)- and insulin (P < 0.001)-mediated dilation, and the NO-dependent responses to both acetylcholine (P = 0.006) and insulin (P = 0.006) were reduced in GDM compared with HC. Insulin stimulation increased phosphorylated eNOS content in HC (P = 0.009) but had no effect in GDM (P = 0.306). Ascorbate treatment increased acetylcholine (P < 0.001)- and insulin (P < 0.001)-mediated dilation in GDM, and endothelial cell nitrotyrosine expression was higher in GDM compared with HC (P = 0.014). Women with a history of GDM have attenuated microvascular vasodilation responses to insulin, and this attenuation is mediated, in part, by reduced NO-dependent mechanisms. Our findings further implicate increased endothelial oxidative stress in this microvascular insulin resistance.NEW & NOTEWORTHY Women who have gestational diabetes during pregnancy are at a greater risk for cardiovascular disease and type 2 diabetes in the decade following pregnancy. The mechanisms mediating this increased risk are unclear. Herein, we demonstrate that insulin-dependent microvascular responses are reduced in women who had gestational diabetes, despite the remission of glucose intolerance. This reduced microvascular sensitivity to insulin may contribute to increased cardiovascular disease and type 2 diabetes risk in these women.

Platelet Decreases following Continuous Renal Replacement Therapy Initiation as a Novel Risk Factor for Renal Nonrecovery.

BACKGROUND: Continuous renal replacement therapy (CRRT) is a form of dialysis used in critically ill patients, and has recently been associated with renal nonrecovery. Decreases in platelets following CRRT initiation are common and are associated with mortality, but associations with renal recovery are unclear. Our objective was to determine if platelet nadir or the degree of platelet decrease following CRRT initiation was associated with renal nonrecovery. METHODS: This is a secondary analysis of the Randomized Evaluation of Normal versus Augmented Level (RENAL) trial. Primary predictors were platelet nadir discretized by median value and percent platelet decrease following CRRT initiation, with cut points evaluated by decile from 30 to 60%. The 2 primary outcomes were time to RRT-independence and RRT-free days. Secondary outcomes were 28-day mortality, 90-day mortality, intensive care unit (ICU)-free, and hospital-free days. RESULTS: Time to RRT independence censored for death was achieved less frequently in patients with low platelet nadir (hazard ratio [HR] 0.77, confidence interval [CI] 0.66-0.91) and in those with >50% platelet decrease (HR 0.84, CI 0.72-0.97). RRT-free days were lower in both low platelet nadir (odds ratio [OR] 0.94, CI 0.90-0.97) and >50% platelet decrease (OR 0.91, CI 0.88-0.95). These groups also had higher rates of 28- and 90-day mortality and fewer ICU-free and hospital-free days. Thrombocytopenia at CRRT initiation was also associated with renal nonrecovery, although the clinical effect was small. CONCLUSIONS: Platelet nadir <100 × 103/µL and platelet decrease by >50% following CRRT initiation were both associated with lower rates of renal recovery. Further research is needed to evaluate mechanisms-linking platelet changes and renal nonrecovery in CRRT.

Natural antibody and complement activation characterize patients with idiopathic nephrotic syndrome.

Focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) are common forms of idiopathic nephrotic syndrome. The causes of these diseases are incompletely understood, but the response of patients to immunosuppressive therapies suggests that their pathogenesis is at least in part immune mediated. Preclinical and clinical research indicates that activation of the classical pathway of complement contributes to glomerular injury in FSGS. Glomerular IgM deposits are also prominent in some patients, raising the possibility that IgM is a trigger of classical pathway activation. In the present study, we examined the pattern of complement activation in the glomeruli and plasma of patients with nephrotic syndrome. We also tested whether patients with FSGS and MCD have elevated levels of natural IgM reactive with epitopes on glomerular endothelial cells and cardiolipin. We found evidence of classical pathway activation in patients with idiopathic nephrotic syndrome compared with healthy control subjects. We also detected higher levels of self-reactive IgM to both targets. Based on these results, IgM and classical pathway activation may contribute to disease pathogenesis in some patients with FSGS and MCD.NEW & NOTEWORTHY IgM is detected in biopsies from some patients with nephrotic syndrome, although this has been attributed to passive trapping of the protein. We found, however, that IgM colocalizes with complement activation fragments in some glomeruli. We also found that affected patients had higher levels of IgM reactive to glomerular endothelial cell epitopes. Thus, IgM activates the complement system in the glomeruli of some patients with nephrotic syndrome and may contribute to injury.

The Association of Platelet Decrease Following Continuous Renal Replacement Therapy Initiation and Increased Rates of Secondary Infections.

OBJECTIVES: Thrombocytopenia is common in critically ill patients treated with continuous renal replacement therapy and decreases in platelets following continuous renal replacement therapy initiation have been associated with increased mortality. Platelets play a role in innate and adaptive immunity, making it plausible that decreases in platelets following continuous renal replacement therapy initiation predispose patients to development of infection. Our objective was to determine if greater decreases in platelets following continuous renal replacement therapy correlate with increased rates of secondary infection. DESIGN: Retrospectivecohort analysis. SETTING: This study uses a continuous renal replacement therapy database from Mayo Clinic (Rochester, MN), a tertiary academic center. PARTICIPANTS: Adult patients who survived until ICU discharge and were on continuous renal replacement therapy for less than 30 days were included. A subgroup analysis was also performed in patients with thrombocytopenia (platelets < 100 × 103/µL) at continuous renal replacement therapy initiation. MEASUREMENTS AND MAIN RESULTS: The primary predictor variable was a decrease in platelets from precontinuous renal replacement therapy levels of greater than 40% or less than or equal to 40%, although multiple cut points were analyzed. The primary outcome was infection after ICU discharge, and secondary endpoints included post-ICU septic shock and post-ICU mortality. Univariable, multivariable, and propensity-adjusted analyses were used to determine associations between the predictor variable and the outcomes. RESULTS: Among 797 eligible patients, 253 had thrombocytopenia at continuous renal replacement therapy initiation. A greater than 40% decrease in platelets after continuous renal replacement therapy initiation was associated in the multivariable-adjusted models with increased odds of post-ICU infection in the full cohort (odds ratio, 1.49; CI, 1.02-2.16) and in the thrombocytopenia cohort (odds ratio, 2.63; CI, 1.35-5.15) cohorts. CONCLUSIONS: Platelet count drop by greater than 40% following continuous renal replacement therapy initiation is associated with an increased risk of secondary infection, particularly in patients with thrombocytopenia at the time of continuous renal replacement therapy initiation. Further research is needed to evaluate the impact of both continuous renal replacement therapy and platelet loss on subsequent infection risk.

Iron Deficiency in Chronic Kidney Disease: Updates on Pathophysiology, Diagnosis, and Treatment.

Anemia is a complication that affects a majority of individuals with advanced CKD. Although relative deficiency of erythropoietin production is the major driver of anemia in CKD, iron deficiency stands out among the mechanisms contributing to the impaired erythropoiesis in the setting of reduced kidney function. Iron deficiency plays a significant role in anemia in CKD. This may be due to a true paucity of iron stores (absolute iron deficiency) or a relative (functional) deficiency which prevents the use of available iron stores. Several risk factors contribute to absolute and functional iron deficiency in CKD, including blood losses, impaired iron absorption, and chronic inflammation. The traditional biomarkers used for the diagnosis of iron-deficiency anemia (IDA) in patients with CKD have limitations, leading to persistent challenges in the detection and monitoring of IDA in these patients. Here, we review the pathophysiology and available diagnostic tests for IDA in CKD, we discuss the literature that has informed the current practice guidelines for the treatment of IDA in CKD, and we summarize the available oral and intravenous (IV) iron formulations for the treatment of IDA in CKD. Two important issues are addressed, including the potential risks of a more liberal approach to iron supplementation as well as the potential risks and benefits of IV versus oral iron supplementation in patients with CKD.

Sex differences in endothelial function in chronic kidney disease.

Vascular dysfunction plays an important role in the etiology of chronic kidney disease (CKD) and is associated with cardiovascular diseases. Sex differences in vascular function are common in clinical and nonclinical populations. However, no data exist in individuals with CKD. The present study tested the hypothesis that sex and/or aging differences exist in vascular function in patients with CKD. Endothelium-dependent dilation (EDD; measured via brachial artery flow-mediated dilation) and endothelium-independent dilation (EID; measured via nitroglycerin-mediated dilation) were assessed. Analyses were adjusted for several variables that could influence vascular function (diabetes, cardiovascular disease, and blood pressure). Women, in general, had higher EDD values than men (6.5 ± 4.9% vs. 4.4 ± 3.4%); however, EID did not differ among these groups. In younger men and women (<55 yr old), EDD and EID were higher (P < 0.05) than their older (≥55 yr old) counterparts (EDD: 7.0 ± 4.1% vs. 4.4 ± 3.8% and EID: 24.0 ± 9.6% vs. 18.3 ± 9.2%). Additionally, younger women exhibited higher (P < 0.05) EDD and EID compared with younger men (EDD: 9.5 ± 6.4% vs. 5.1 ± 3.8%, P = 0.01, and EID: 24.0 ± 9.6% vs. 18.3 ± 9.2%). No differences in EDD and EID were present between older men and women with CKD. Diabetes independently predicted lower EID but not EDD in men and women. Blood pressure and cardiovascular disease did not predict EDD or EID. This is the first study to show significant sex differences in vascular function. Moreover, these differences are evident between younger men and women with CKD but are abolished with age. Additional studies are needed to better understand the mechanisms that may underlie sex differences in vascular dysfunction with CKD.

KIM-1 and Kidney Disease Progression in Autosomal Dominant Polycystic Kidney Disease: HALT-PKD Results.

BACKGROUND: Cyst compression of renal tubules plays a role in the progression of autosomal dominant polycystic kidney disease (ADPKD) and may induce expression of kidney injury molecule-1 (KIM-1). Whether urinary KIM-1 indexed for creatinine (uKIM-1/Cr) is a prognostic marker of disease progression in ADPKD is unknown.In this secondary analysis of a prospective cohort study, we sought to determine whether patients with high as opposed to low uKIM-1/CR at baseline had greater rates of eGFR loss and height-adjusted total kidney volume (HtTKV) increase. METHODS: Baseline uKIM-1/Cr values were obtained from 754 participants in Halt Progression of Polycystic Kidney Disease (HALT-PKD) studies A (early ADPKD) and B (late ADPKD). The predictor was uKIM-1/Cr, which was dichotomized by a median value of 0.2417 pg/g, and the primary outcomes were measured longitudinally over time. Mixed-effects linear models were used in the analysis to calculate the annual slope of change in eGFR and HtTKV. RESULTS: Patients with high uKIM-1/Cr (above the median) had an annual decline in eGFR that was 0.47 mL/min greater than that in those with low uKIM-1/Cr (p = 0.0015) after adjustment for all considered covariates. This association was seen in study B patients alone (0.45 mL/min; p = 0.009), but not in study A patients alone (0.42 mL/min; p = 0.06). High baseline uKIM-1/Cr was associated with higher HtTKV in the baseline cross-sectional analysis compared to low uKIM-1/Cr (p = 0.02), but there was no difference between the groups in the mixed-effects model annual slopes. CONCLUSION: Elevated baseline uKIM-1/Cr is associated with a greater decline in eGFR over time. Further research is needed to determine whether uKIM-1/Cr improves risk stratification in patients with ADPKD.

Effects of Baseline Thrombocytopenia and Platelet Decrease Following Renal Replacement Therapy Initiation in Patients With Severe Acute Kidney Injury.

OBJECTIVES: Thrombocytopenia is common in critically ill patients with severe acute kidney injury and may be worsened by the use of renal replacement therapy. In this study, we evaluate the effects of renal replacement therapy on subsequent platelet values, the prognostic significance of a decrease in platelets, and potential risk factors for platelet decreases. DESIGN: Post hoc analysis of the Acute Renal Failure Trial Network Study. SETTING: The Acute Renal Failure Trial Network study was a multicenter, prospective, randomized, parallel-group trial of two strategies for renal replacement therapy in critically ill patients with acute kidney injury conducted between November 2003 and July 2007 at 27 Veterans Affairs and university-affiliated medical centers. SUBJECTS: The Acute Renal Failure Trial Network study evaluated 1,124 patients with severe acute kidney injury requiring renal replacement therapy. INTERVENTIONS: Predictor variables were thrombocytopenia at initiation of renal replacement therapy and platelet decrease following renal replacement therapy initiation. MEASUREMENTS AND MAIN RESULTS: Outcomes were mortality at 28 days, 60 days, and 1 year, renal recovery, renal replacement therapy free days, ICU-free days, and hospital-free days. Baseline thrombocytopenia in patients requiring renal replacement therapy was associated with increased mortality and was also associated with lower rates of renal recovery. A decrease in platelet values following renal replacement therapy initiation was associated with increased mortality. Continuous renal replacement therapy was not an independent predictor of worsening thrombocytopenia compared with those treated with intermittent hemodialysis. CONCLUSIONS: Baseline thrombocytopenia and platelet decrease following renal replacement therapy initiation were associated with increased mortality, and baseline thrombocytopenia was associated with decreased rates of renal recovery. Continuous renal replacement therapy did not decrease platelets compared with hemodialysis.

Continuous Renal Replacement Therapy Dosing in Critically Ill Patients: A Quality Improvement Initiative.

RATIONALE & OBJECTIVE: Clinical practice guidelines recommend delivering a continuous renal replacement therapy (CRRT) dose of 20 to 25mL/kg/h. However, practice patterns nationwide are highly variable; this inconsistent prescribing may lead to errors in medication dosing and increase rates of electrolyte and acid-base abnormalities. We describe an initiative to standardize CRRT practice patterns and reduce dosing variability. STUDY DESIGN: Quality improvement study. SETTING & PARTICIPANTS: Adult patients treated with CRRT at the University of Colorado Hospital between January 2016 and October 2017. QUALITY IMPROVEMENT ACTIVITIES: An assessment of the magnitude of the variability in CRRT dosing and the following specific interventions were implemented during the course of 1 year: (1) modification of the electronic medical record (EMR) to include calculated average 24-hour dose in real time, (2) modification of the CRRT procedure note to include comments on dosing, (3) modification of the CRRT order set to display calculations, and (4) yearly educational sessions for renal fellows outlining CRRT-specific dosing targets. OUTCOMES: The primary outcome was weekly percentage of CRRT treatments with an average delivered daily dose of 20 to 25mL/kg/h. Process and balancing outcomes included CRRT flowsheet accuracy, documentation of rates of delivered dose, and nursing satisfaction. ANALYTICAL APPROACH: Rates of weekly CRRT dosing in compliance with national guidelines were determined and used to create run charts showing compliance rates before and after the quality improvement interventions. RESULTS: Among 837 treatments before the intervention, 279 (33%) daily CRRT sessions achieved an average dose of 20 to 25mL/kg/h. Following implementation of interventions, 631 of 952 (66%) treatments achieved this goal. Week-to-week variation in dosing was significantly reduced. LIMITATIONS: A single-center study generating data that may not be generalizable to institutions with different CRRT nursing models or different EMR systems. CONCLUSIONS: Changes to the EMR and documentation templates and education of CRRT providers about dosing were associated with doubling of the rate of appropriate CRRT dosing and reduction in dosing variability.

Integrated safety studies of the urate reabsorption inhibitor lesinurad in treatment of gout.

Objective: Lesinurad (LESU) is a selective urate reabsorption inhibitor approved at 200 mg daily for use with a xanthine oxidase inhibitor (XOI) to treat hyperuricaemia in gout patients failing to achieve target serum urate on XOI. The aim of the study was to investigate the long-term safety of LESU + XOI therapy. Methods: Safety data were pooled from three 12-month phase III (core) trials evaluating LESU 200 and 400 mg/day combined with an XOI (LESU200+XOI and LESU400+XOI), and two 12-month extension studies using descriptive statistics. To adjust for treatment duration, treatment-emergent adverse events (TEAEs) were expressed as exposure-adjusted incidence rates (patients with events per 100 person-years). Results: In the core studies, exposure-adjusted incidence rates for total and total renal-related TEAEs were comparable for XOI alone and LESU200+XOI but higher with LESU400+XOI. Exposure-adjusted incidence rates for serum creatinine (sCr) elevations ⩾1.5×baseline were 2.9, 7.3 and 18.7, respectively. Resolution (sCr ⩽1.2×baseline) occurred in 75-90% of all events, with 66-75% occurring without any study medication interruption. Major adverse cardiovascular events were 3, 4 and 9 with XOI, LESU200+XOI and LESU400+XOI, respectively. Longer exposure in core+extension studies did not increase rates for any safety signals. Conclusion: At the approved dose of 200 mg once-daily combined with an XOI, LESU did not increase renal, cardiovascular or other adverse events compared with XOI alone, except for sCr elevations. With extended exposure in the core+extension studies, the safety profile was consistent with that observed in the core studies, and no new safety concerns were identified.

Vascular Function and Uric Acid-Lowering in Stage 3 CKD.

Hyperuricemia may contribute to endothelial dysfunction in CKD. We evaluated whether lowering serum uric acid levels with allopurinol improves endothelial dysfunction in 80 participants ≥18 years of age with stage 3 CKD and asymptomatic hyperuricemia (≥7 mg/dl in men and ≥6 mg/dl in women) randomized in a double-blinded manner to receive placebo or allopurinol for 12 weeks. Randomization was stratified according to presence or absence of diabetes mellitus. We measured vascular endothelial function by brachial artery flow-mediated dilation. No significant differences existed between groups at baseline; 61% of the participants had diabetes mellitus in both groups. The placebo and the allopurinol groups had baseline serum uric acid levels (SDs) of 8.7 (1.6) mg/dl and 8.3 (1.4) mg/dl, respectively, and baseline flow-mediated dilation values (SDs) of 6.0% (5.0%) and 4.8% (5.0%), respectively. Compared with placebo, allopurinol lowered serum uric acid significantly but did not improve endothelial function. In participants without diabetes mellitus, allopurinol associated with a trend toward improved flow-mediated dilation (+1.4% [3.9%] versus -0.7% [4.1%] with placebo), but this was not statistically significant (P=0.26). Furthermore, we did not detect significant differences between groups in BP or serum levels of markers of inflammation and oxidative stress. In conclusion, allopurinol effectively and safely lowered serum uric acid levels in adults with stage 3 CKD and asymptomatic hyperuricemia but did not improve endothelial function in this sample of patients.

The safety of achieved iron stores and their effect on IV iron and ESA use: post-hoc results from a randomized trial of ferric citrate as a phosphate binder in dialysis
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Iron stores assuring optimal efficacy/safety for erythropoiesis are unknown in the dialysis population. Using multicenter trial data, we related safety profiles, erythropoiesis-stimulating agent (ESA), and intravenous iron dosing to achieved iron stores in 441 subjects randomized 2 : 1 to ferric citrate or active control as their phosphate binder over 52 weeks. Intravenous iron was given at each site's discretion if ferritin ≤ 1,000 ng/mL and transferrin saturation ≤ 30%. Multivariable time-dependent Cox regression jointly related the primary safety outcome (composite of cardiac, infection, gastrointestinal, and hepatobiliary serious adverse events) to moving averages of ferritin and transferrin saturation over the preceding 90 days with covariate adjustment. Multivariable generalized estimating equations related elevated ESA and intravenous iron doses to trailing 90-day averages of ferritin and transferrin saturation with covariate adjustment. The adjusted hazard ratio for the safety composite per 10% increase in transferrin saturation was 0.84 (95% confidence interval 0.68 - 1.02, p = 0.08) and 1.09 (0.86 - 1.35, p = 0.48) per 400 ng/mL increase in ferritin. The adjusted hazard ratio for the safety composite was 0.50 (0.29 - 0.88, p = 0.016) for the highest transferrin saturation tertile vs. the lowest. Adjusted odds ratios for higher intravenous iron dose were lower in the highest (0.23 [0.16 - 0.35], p < 0.001) and middle transferrin saturation tertile (0.42 [0.31 - 0.57], p < 0.001) vs. lowest. Incidence of elevated ESA dose was lower in the highest transferrin saturation tertile (p = 0.01). Ferritin did not predict clinical events or ESA dose. Transferrin saturation may be a better marker than serum ferritin to judge optimal iron stores in dialysis patients. Transferrin saturations > 34% are safe and provide maximal efficacy.
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Higher plasma transforming growth factor (TGF)-ß is associated with kidney disease in older community dwelling adults.

BACKGROUND: TGF-ß is induced in the vasculature with aging suggesting that high plasma TGF-ß levels may be a risk factor for chronic kidney disease (CKD) in older adults. METHODS: We conducted a cross-sectional analysis of the association between plasma TGF-ß levels and CKD including data for 1722 older adults who had participated in the 1996/97 visit of the Cardiovascular Health Study (CHS). Prevalent CKD was defined as eGFR < 60 mL/min/1.73 m2 or urinary albumin/creatinine ratio (ACR) ≥30 mg/g. We also evaluated whether baseline TGF-ß levels predicted change in eGFR, cardiovascular (CV) events, or mortality in longitudinal analysis. RESULTS: Plasma TGF-ß levels were significantly and independently associated with lower eGFR in cross-sectional analysis. Doubling of TGF-ß was significantly associated with lower eGFR (ß estimate after adjusting for CV risk factors = -1.18, 95% CI -2.03, -0.32). We observed no association with albuminuria. There was no association between baseline TGF-ß and change in eGFR, but each doubling of TGF-ß at baseline was associated with increased risk of a composite outcome of CV events and mortality, adjusted HR 1.10 (95% C.I. 1.02- 1.20, p = 0.006). CONCLUSION: In this large cohort of community-dwelling older individuals, high plasma TGF-ß levels are modestly, but independently associated with lower eGFR but not with albuminuria in cross-sectional analysis. In addition, TGF-ß levels are associated with increased risk of CV events and mortality. Further research is needed to determine the direction of association between plasma TGF-ß and the risk of CKD and CKD-associated morbidities in older adults.

A Decline in Intraoperative Renal Near-Infrared Spectroscopy Is Associated With Adverse Outcomes in Children Following Cardiac Surgery.

OBJECTIVES: Renal near-infrared spectroscopy is known to be predictive of acute kidney injury in children following cardiac surgery using a series of complex equations and area under the curve. This study was performed to determine if a greater than or equal to 20% reduction in renal near-infrared spectroscopy for 20 consecutive minutes intraoperatively or within the first 24 postoperative hours is associated with 1) acute kidney injury, 2) increased acute kidney injury biomarkers, or 3) other adverse clinical outcomes in children following cardiac surgery. DESIGN: Prospective single center observational study. SETTING: Pediatric cardiac ICU. PATIENTS: Children less than or equal to age 4 years who underwent cardiac surgery with the use of cardiopulmonary bypass during the study period (June 2011-July 2012). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A reduction in near-infrared spectroscopy was not associated with acute kidney injury. Nine of 12 patients (75%) with a reduction in renal near-infrared spectroscopy did not develop acute kidney injury. The remaining three patients had mild acute kidney injury (pediatric Risk, Injury, Failure, Loss, End stage-Risk). A reduction in renal near-infrared spectroscopy was associated with the following adverse clinical outcomes: 1) a longer duration of mechanical ventilation (p = 0.05), 2) longer intensive care length of stay (p = 0.05), and 3) longer hospital length of stay (p < 0.01). A decline in renal near-infrared spectroscopy in combination with an increase in serum interleukin-6 and serum interleukin-8 was associated with a longer intensive care length of stay, and the addition of urine interleukin-18 to this was associated with a longer hospital length of stay. CONCLUSIONS: In this cohort, the rate of acute kidney injury was much lower than anticipated thereby limiting the evaluation of a reduction in renal near-infrared spectroscopy as a predictor of acute kidney injury. A greater than or equal to 20% reduction in renal near-infrared spectroscopy was significantly associated with adverse outcomes in children following cardiac surgery. The addition of specific biomarkers to the model was predictive of worse outcomes in these patients. Thus, real-time evaluation of renal near-infrared spectroscopy using the specific levels of change of a 20% reduction for 20 minutes may be useful in predicting prolonged mechanical ventilation and other adverse outcomes in children undergoing cardiac surgery.

Ferric Citrate Reduces Intravenous Iron and Erythropoiesis-Stimulating Agent Use in ESRD.

Ferric citrate (FC) is a phosphate binder with shown efficacy and additional effects on iron stores and use of intravenous (iv) iron and erythropoiesis-stimulating agents (ESAs). We provide detailed analyses of changes in iron/hematologic parameters and iv iron/ESA use at time points throughout the active control period of a phase 3 international randomized clinical trial. In all, 441 subjects were randomized (292 to FC and 149 to sevelamer carbonate and/or calcium acetate [active control (AC)]) and followed for 52 weeks. Subjects on FC had increased ferritin and transferrin saturation (TSAT) levels compared with subjects on AC by week 12 (change in ferritin, 114.1±29.35 ng/ml; P<0.001; change in TSAT, 8.62%±1.57%; P<0.001). Change in TSAT plateaued at this point, whereas change in ferritin increased through week 24, remaining relatively stable thereafter. Subjects on FC needed less iv iron compared with subjects on AC over 52 weeks (median [interquartile range] dose=12.9 [1.0-28.9] versus 26.8 [13.4-47.6] mg/wk; P<0.001), and the percentage of subjects not requiring iv iron was higher with FC (P<0.001). Cumulative ESA over 52 weeks was lower with FC than AC (median [interquartile range] dose=5303 [2023-9695] versus 6954 [2664-12,375] units/wk; P=0.04). Overall, 90.3% of subjects on FC and 89.3% of subjects on AC experienced adverse events. In conclusion, treatment with FC as a phosphate binder results in increased iron parameters apparent after 12 weeks and reduces iv iron and ESA use while maintaining hemoglobin over 52 weeks, with a safety profile similar to that of available binders.

Fructose and uric acid in diabetic nephropathy.

Clinical studies have reported associations between serum uric acid levels and the development of diabetic nephropathy, but the underlying mechanisms remain elusive. There is evidence from animal studies that blocking uric acid production protects the kidney from tubulointerstitial injury, which may suggest a causal role for uric acid in the development of diabetic tubular injury. In turn, when fructose, which is endogenously produced in diabetes via the polyol pathway, is metabolised, uric acid is generated from a side-chain reaction driven by ATP depletion and purine nucleotide turnover. For this reason, uric acid derived from endogenous fructose could cause tubulointerstitial injury in diabetes. Accordingly, our research group recently demonstrated that blocking fructose metabolism in a diabetic mouse model mitigated the development of tubulointerstitial injury by lowering tubular uric acid production. In this review we discuss the relationship between uric acid and fructose as a novel mechanism for the development of diabetic tubular injury.

Hydroxychloroquine use is associated with reduced mortality risk in older adults with rheumatoid arthritis.

BACKGROUND: There is little robust data about the cardiovascular safety of hydroxychloroquine in patients with rheumatoid arthritis (RA), who often have cardiovascular comorbidities. We examined the association between use of hydroxychloroquine (HCQ) in patients with RA and major adverse cardiovascular events (MACE). METHODS: In a retrospective cohort of Medicare beneficiaries aged ≥ 65 years with RA, we identified patients who initiated HCQ (users) and who did not initiate HCQ (non-users) between January 2015-June 2017. Each HCQ user was matched to 2 non-users of HCQ using propensity score derived from patient baseline characteristics. The primary outcome was the occurrence of MACE, defined as acute admissions for stroke, myocardial infarction, or heart failure. Secondary outcomes included all-cause mortality and the composite of MACE and all-cause mortality. Cox proportional hazards model was used to compare outcomes between HCQ users to non-users. RESULTS: The study included 2380 RA patients with incident HCQ use and matched 4633 HCQ non-users over the study period. The mean follow-up duration was 1.67 and 1.63 years in HCQ non-users and users, respectively. In multivariable models, use of HCQ was not associated with the risk of MACE (hazard ratio 1.1; 95% CI: 0.832-1.33). However, use of HCQ was associated with a lower risk of all-cause mortality (HR: 0.54; 95% CI: 0.45-0.64) and the composite of all-cause mortality and MACE (HR 0.67; 95% CI: 0.58-0.78). CONCLUSION: HCQ use was independently associated with a lower risk of mortality in older adults with RA but not with incidence of MACE events. Key Points • Using an incident user design (to avoid the biases of a prevalent user design) and a population-based approach, we examined the effect of hydroxychloroquine (HCQ) on the risk of major cardiovascular events (MACE) in older patients with RA. • We did not find an association between HCQ use and incident MACE. We did, however, find a significant association with the composite outcome (MACE and all-cause mortality) driven by a significant reduction in all-cause mortality with HCQ use.

Trends of Blood Pressure Control in Chronic Kidney Disease Among US Adults: Findings From NHANES 2011 to 2020.

BACKGROUND: Hypertension afflicts most patients with chronic kidney disease (CKD) and contributes to kidney disease progression, cardiovascular disease, and death in this patient population. The evidence and clinical guidelines support lowering blood pressure (BP) goals in patients with CKD. We evaluated if BP control improved among US adults with CKD. METHODS AND RESULTS: In the NHANES (National Health and Nutrition Examination Survey) for the periods 2011 to 2014, 2015 to 2016, and 2017 to 2020, we identified individuals with CKD defined as estimated glomerular filtration rate 20 to 59 mL/min per 1.73 m2 or urinary albumin/creatinine ratio≥30 mg/g. The following systolic BP categories were evaluated: <120, 120 to 129, 130 to 139, and ≥140 mm Hg. All measures were tested for differences between year groups accounting for sample strata, clusters, and weights. During the periods of 2011 to 2014, 2015 to 2016, and 2017 to 2020, the prevalence of CKD was stable at 14%, 13%, and 13%, respectively (P=0.4). Among those with CKD, the proportion of individuals with self-reported hypertension or taking BP medications increased from 66 in 2011 to 2014, to 69 and 86% in 2015 to 2016 and 2017 to 2020, respectively (P<0.0001). Although the number of BP medications prescribed increased significantly over time, less than half of the individuals with CKD had well-controlled BP based on the current guidelines. CONCLUSIONS: Although BP recognition has improved among those with CKD, a significant number of individuals with CKD do not meet their BP goal.

Effect of acute heparin administration on glycocalyx thickness and endothelial function in healthy younger adults.

The endothelial glycocalyx is a dynamic, gel-like layer that is critical to normal vascular endothelial function. Heparin impairs the endothelial glycocalyx and reduces vascular endothelial function in a murine model; however, this has yet to be tested in healthy humans. We hypothesized that a single bolus dose of heparin would increase circulating glycocalyx components and decrease endothelial glycocalyx thickness resulting in blunted brachial artery vasodilation in healthy younger adults. Healthy adults (n = 19, aged 18-39 yr, 53% female) underwent measurements of the endothelial glycocalyx and vascular endothelial function at baseline and after a single bolus 5,000 U dose of heparin. The glycocalyx components syndecan-1 and heparan sulfate were measured from plasma samples using enzyme-linked immunosorbent assays. Glycocalyx thickness was determined as perfused boundary region (PBR) in sublingual microvessels using the GlycoCheck. Endothelial function was measured via ultrasonography and quantified as brachial artery flow-mediated dilation (FMD). Following acute heparin administration, there was no increase in syndecan-1 or heparan sulfate (P = 0.90 and P = 0.49, respectively). In addition, there was no change in PBR 4-7 µm (P = 0.55), PBR 10-25 µm (P = 0.63), or 4-25 µm (P = 0.49) after heparin treatment. Furthermore, we did not observe a change in FMDmm (P = 0.23), FMD% (P = 0.35), or plasma nitrite concentrations (P = 0.10) in response to heparin. Finally, time to peak dilation and peak FMD normalized to shear stress were unchanged following heparin (P = 0.59 and P = 0.21, respectively). Our pilot study suggests that a single bolus intravenous dose of heparin does not result in endothelial glycocalyx degradation or vascular endothelial dysfunction in healthy younger adults.NEW & NOTEWORTHY The endothelial glycocalyx's role in modulating vascular endothelial dysfunction with aging and disease is becoming increasingly recognized. This study presents novel findings that acute heparin administration is not a feasible method to experimentally degrade the endothelial glycocalyx and measure concurrent changes in vascular endothelial function in healthy humans. Alternative approaches will be needed to translate findings from preclinical studies and test the effects of acute endothelial glycocalyx degradation on vascular endothelial function in humans.