A characterization of patients with low soluble urokinase plasminogen activator receptor who died within 90 days of hospital discharge.

Soluble urokinase plasminogen activator receptor (suPAR) is a marker of systemic chronic inflammation. Elevated suPAR levels are associated with adverse clinical outcomes, but a small subset of patients with low suPAR also experience poor outcomes. Therefore, we aimed to characterize patients presenting to the emergency department with low suPAR (<3 ng/mL) who died within 90 days after discharge in a registry-based study. Compared to patients with low suPAR who survived (n = 15 122), those who died within 90 days (n = 87) had higher age (75.4 years), higher medication use (7.0; 71.3% with polypharmacy) and more blood tests outside reference intervals (5.0) (including C-reactive protein, neutrophils and albumin), and the most common diagnoses were chronic pulmonary disease (27.6%), cerebrovascular disease (18.4%) and dementia (11.5%). Patients with low suPAR were more morbid than what was reflected by suPAR alone. Future studies must determine which factors that contribute the most to potential algorithms when stratifying patients based on their risk of adverse clinical outcomes. These data indicate that inclusion of medication data could be relevant.

Inappropriate prescribing in patients with kidney disease: A rapid review of prevalence, associated clinical outcomes and impact of interventions.

BACKGROUND: The prevalence of patients with chronic kidney disease (CKD) and polypharmacy is increasing and has amplified the importance of examining inappropriate prescribing (IP) in CKD. This review focuses on the latest research regarding the prevalence of IP in CKD and the related adverse clinical effects and explores new interventions against IP. METHOD: A literature search was performed using PubMed, EMBASE and the Cochrane Library searching articles published between June 2016 and March 2022. RESULTS: Twenty-seven studies were included. An IP prevalence of 12.6% to 96% and 0.3% to 66% was reported in hospital and outpatient settings, respectively. In nonhospital settings, the prevalence of IP varied between 3.9% and 60%. IP was associated with higher risk of hospitalisation (HR 1.46, 95% CI 1.17-1.81), higher bleeding rate (HR 2.34, 95% CI 1.32 to 3.37) and higher risk of all-cause mortality (OR 1.07, 95% CI 1.02 to 1.13). Three studies reported the impact of interventions on IP. CONCLUSION: This review highlights widespread IP in CKD patients across healthcare settings, with varying prevalence rates. IP is substantially linked to adverse outcomes in patients. While limited interventions show promise, urgent research is needed to develop effective strategies addressing IP and improving CKD patient care.

Performance of Panel-Estimated GFR Among Hospitalized Older Adults.

RATIONALE & OBJECTIVE: Older adults represent nearly half of all hospitalized patients and are vulnerable to inappropriate dosing of medications eliminated through the kidneys. However, few studies in this population have evaluated the performance of equations for estimating the glomerular filtration rate (GFR)-particularly those that incorporate multiple filtration markers. STUDY DESIGN: Cross-sectional diagnostic test substudy of a randomized clinical trial. SETTING & PARTICIPANTS: Adults≥65 years of age presenting to the emergency department of Copenhagen University Hospital Amager and Hvidovre in Hvidovre, Denmark, between October 2018 and April 2021. TESTS COMPARED: Measured GFR (mGFR) determined using 99mTc-DTPA plasma clearance compared with estimated GFR (eGFR) calculated using 6 different equations based on creatinine; 3 based on creatinine and cystatin C combined; and 2 based on panels of markers including creatinine, cystatin C, ß-trace protein (BTP) and/or ß2-microglobulin (B2M). OUTCOME: The performance of each eGFR equation compared with mGFR with respect to bias, relative bias, inaccuracy (1-P30), and root mean squared error (RMSE). RESULTS: We assessed eGFR performance for 106 patients (58% female, median age 78.3 years, median mGFR 62.9mL/min/1.73m2). Among the creatinine-based equations, the 2009 CKD-EPIcr equation yielded the smallest relative bias (+4.2%). Among the creatinine-cystatin C combination equations, the 2021 CKD-EPIcomb equation yielded the smallest relative bias (-3.4%), inaccuracy (3.8%), and RMSE (0.139). Compared with the 2021 CKD-EPIcomb, the CKD-EPIpanel equation yielded a smaller RMSE (0.136) but larger relative bias (-4.0%) and inaccuracy (5.7%). LIMITATIONS: Only White patients were included; only a subset of patients from the original clinical trial underwent GFR measurement; and filtration marker concentration can be affected by subclinical changes in volume status. CONCLUSIONS: The 2009 CKD-EPIcr, 2021 CKD-EPIcomb, and CKD-EPIpanel equations performed best and notably outperformed their respective full-age spectrum equations. The addition of cystatin C to creatinine-based equations improved performance, while the addition of BTP and/or B2M yielded minimal improvement. FUNDING: Grants from public sector industry (Amgros I/S) and government (Capital Region of Denmark). TRIAL REGISTRATION: Registered at ClinicalTrials.gov with registration number NCT03741283. PLAIN-LANGUAGE SUMMARY: Inaccurate kidney function assessment can lead to medication errors, a common cause of hospitalization and early readmission among older adults. Several novel methods have been developed to estimate kidney function based on a panel of kidney function markers that can be measured from a single blood sample. We evaluated the accuracy of these new methods (relative to a gold standard method) among 106 hospitalized older adults. We found that kidney function estimates combining 2 markers (creatinine and cystatin C) were highly accurate and noticeably more accurate than estimates based on creatinine alone. Estimates incorporating additional markers such as ß-trace protein and ß2-microglobulin did not further improve accuracy.

Estimated glomerular filtration rate based on creatinine, cystatin C, ß-trace protein and ß2 microglobulin in patients undergoing nontraumatic lower extremity amputation.

AIMS: The study's aim is to compare current and new equations for estimating glomerular filtration rate (GFR) based on creatinine, cystatin C, ß-trace protein (BTP) and ß2 microglobulin (B2M) among patients undergoing major amputation. METHODS: This is a secondary analysis of data from a prospective cohort study investigating patients undergoing nontraumatic lower extremity amputation. Estimated GFR (eGFR) was calculated using equations based on creatinine (eGFRcre[2009] and eGFRcre[2021]), cystatin C (eGFRcys), the combination of creatinine and cystatin C (eGFRcomb[2012] and eGFRcomb[2021]) or a panel of all 4 filtration markers (eGFRpanel). Primary outcome was changed in eGFR across amputation according to each equation. Two case studies of prior amputation with GFR measured by 99mTc-DTPA clearance are described to illustrate the relative accuracies of each eGFR equation. RESULTS: Analysis of the primary outcome included 29 patients (median age 75 years, 31% female). Amputation was associated with a significant decrease in creatinine concentration (-0.09 mg/dL, P = 0.004), corresponding to a significant increase in eGFRcre[2009] (+6.1 mL/min, P = 0.006) and eGFRcre[2021] (+6.3 mL/min, P = 0.006). Change across amputation was not significant for cystatin C, BTP, B2M or equations incorporating these markers (all P > 0.05). In both case studies, eGFRcre[2021] yielded the largest positive bias, eGFRcys yielded the largest negative bias and eGFRcomb[2012] and eGFRcomb[2021] yielded the smallest absolute bias. CONCLUSION: Creatinine-based estimates were substantially higher than cystatin C-based estimates before amputation and significantly increased across amputation. Estimates combining creatinine and cystatin were stable across amputation, while the addition of BTP and B2M is unlikely to be clinically relevant.

Low cerebral energy metabolism in hepatic encephalopathy reflects low neuronal energy demand. Role of ammonia-induced increased GABAergic tone.

Hepatic encephalopathy (HE) is a frequent and devastating but generally reversible neuropsychiatric complication secondary to chronic and acute liver failure. During HE, brain energy metabolism is markedly reduced and it remains unclear whether this is due to external or internal energy supply limitations, or secondary to depressed neuronal cellular functions - and if so, which mechanisms that are in play. The extent of deteriorated cerebral function correlates to blood ammonia levels but the metabolic link to ammonia is not clear. Early studies suggested that high levels of ammonia inhibited key tricarboxylic acid (TCA) cycle enzymes thus limiting mitochondrial energy production and oxygen consumption; however, later studies by us and others showed that this is not the case in vivo. Here, based on a series of translational studies from our group, we advocate the view that the low cerebral energy metabolism of HE is likely to be caused by neuronal metabolic depression due to an elevated GABAergic tone rather than by restricted energy availability. The increased GABAergic tone seems to be secondary to synthesis of large amounts of glutamine in astrocytes for detoxification of ammonia with the glutamine acting as a precursor for elevated neuronal synthesis of vesicular GABA.

Utility of suPAR and NGAL for AKI Risk Stratification and Early Optimization of Renal Risk Medications among Older Patients in the Emergency Department.

Diagnosis of acute kidney injury (AKI) based on plasma creatinine often lags behind actual changes in renal function. Here, we investigated early detection of AKI using the plasma soluble urokinase plasminogen activator receptor (suPAR) and neutrophil gelatinase-sssociated lipocalin (NGAL) and observed the impact of early detection on prescribing recommendations for renally-eliminated medications. This study is a secondary analysis of data from the DISABLMENT cohort on acutely admitted older (≥65 years) medical patients (n = 339). Presence of AKI according to kidney disease: improving global outcomes (KDIGO) criteria was identified from inclusion to 48 h after inclusion. Discriminatory power of suPAR and NGAL was determined by receiver-operating characteristic (ROC). Selected medications that are contraindicated in AKI were identified in Renbase®. A total of 33 (9.7%) patients developed AKI. Discriminatory power for suPAR and NGAL was 0.69 and 0.78, respectively, at a cutoff of 4.26 ng/mL and 139.5 ng/mL, respectively. The interaction of suPAR and NGAL yielded a discriminatory power of 0.80, which was significantly higher than for suPAR alone (p = 0.0059). Among patients with AKI, 22 (60.6%) used at least one medication that should be avoided in AKI. Overall, suPAR and NGAL levels were independently associated with incident AKI and their combination yielded excellent discriminatory power for risk determination of AKI.

Functional characterization of α7 nicotinic acetylcholine and NMDA receptor signaling in SH-SY5Y neuroblastoma cells in an ERK phosphorylation assay.

In the present study, the functional properties of α7 nicotinic acetylcholine receptors (α7 nAChRs) and N-methyl-D-aspartate receptors (NMDARs) endogenously expressed in SH-SY5Y human neuroblastoma cells were characterized in an extracellular-signal regulated kinase (ERK) phosphorylation assay. Both choline and N-methyl-D-aspartate (NMDA) mediated robust concentration-dependent increases in ERK phosphorylation in the SH-SY5Y cells, exhibiting EC50 values in good agreement with those reported for the agonists at recombinant α7 nAChRs and NMDARs, respectively. Importantly, the responses evoked by choline (10 mM) and by NMDA (50 µM) were significantly inhibited by the α7-selective antagonist α-bungarotoxin (100 nM) and by the NMDAR-selective antagonist MK-801 (50 µM), respectively. The increased ERK phosphorylation levels observed upon co-application of choline (1, 3, 10 mM) and NMDA (50 µM) compared to those produced by the two agonists on their own were fully reconcilable with additive effects and did not reveal substantial synergy between α7 nAChR and NMDAR signaling. Interestingly, however, the responses evoked by the "choline (10 mM) - NMDA (50 µM)" combination were almost completely inhibited by α-bungarotoxin (100 nM) as well as by MK-801 (50 µM), suggesting some sort of a link between α7 nAChR- and NMDAR-mediated ERK phosphorylation. Finally, oligomeric amyloid-ß1-42 peptide (1000 nM) mediated robust inhibition of the ERK phosphorylation induced by choline (10 mM), NMDA (50 µM) and the "choline (10 mM) - NMDA (50 µM)" combination. In conclusion, ERK phosphorylation measurements in SH-SY5Y cells provides a robust assay for studies of α7 nAChR- and NMDAR-mediating signaling and putative functional interactions between the receptors.

Probing the putative α7 nAChR/NMDAR complex in human and murine cortex and hippocampus: Different degrees of complex formation in healthy and Alzheimer brain tissue.

α7 nicotinic acetylcholine receptors (nAChRs) and N-methyl-D-aspartate receptors (NMDARs) are key mediators of central cholinergic and glutamatergic neurotransmission, respectively. In addition to numerous well-established functional interactions between α7 nAChRs and NMDARs, the two receptors have been proposed to form a multimeric complex, and in the present study we have investigated this putative α7 nAChR/NMDAR assembly in human and murine brain tissues. By α-bungarotoxin (BGT) affinity purification, α7 and NMDAR subunits were co-purified from human and murine cortical and hippocampal homogenates, substantiating the notion that the receptors are parts of a multimeric complex in the human and rodent brain. Interestingly, the ratios between GluN1 and α7 levels in BGT pull-downs from cortical homogenates from Alzheimer's disease (AD) brains were significantly lower than those in pull-downs from non-AD controls, indicating a reduced degree of α7 nAChR/NMDAR complex formation in the diseased tissue. A similar difference in GluN1/α7 ratios was observed between pull-downs from cortical homogenates from adult 3xTg-AD and age-matched wild type (WT) mice, whereas the GluN1/α7 ratios determined in pull-downs from young 3xTg-AD and age-matched WT mice did not differ significantly. The observation that pretreatment with oligomeric amyloid-ß1-42 reduced GluN1/α7 ratios in BGT pull-downs from human cortical homogenate in a concentration-dependent manner provided a plausible molecular mechanism for this observed reduction. In conclusion, while it will be important to further challenge the existence of the putative α7 nAChR/NMDAR complex in future studies applying other methodologies than biochemical assays and to investigate the functional implications of this complex for cholinergic and glutamatergic neurotransmission, this work supports the formation of the complex and presents new insights into its regulation in healthy and diseased brain tissue.