Short-term association between outdoor temperature and the hydration-marker copeptin: a pooled analysis in five cohorts.

BACKGROUND: Whereas outdoor temperature is linked to both mortality and hydration status, the hormone vasopressin, measured through the surrogate copeptin, is a marker of cardiometabolic risk and hydration. We recently showed that copeptin has a seasonal pattern with higher plasma concentration in winter. Here, we aimed to investigate the association between outdoor temperature and copeptin. METHODS: Copeptin was analysed in fasting plasma from five cohorts in Malmö, Sweden (n = 26,753, 49.7% men, age 18-86 years). We utilized a multivariable adjusted non-linear spline model with four knots to investigate the association between short-term temperature (24 h mean apparent) and log copeptin z-score. FINDINGS: We found a distinct non-linear association between temperature and log copeptin z-score, with both moderately low and high temperatures linked to higher copeptin concentration (p < 0.0001). Between 0 °C and nadir at the 75th temperature percentile (corresponding to 14.3 °C), log copeptin decreased 0.13 z-scores (95% CI 0.096; 0.16), which also inversely corresponded to the increase in z-score log copeptin between the nadir and 21.3 °C. INTERPRETATION: The J-shaped association between short-term temperature and copeptin resembles the J-shaped association between temperature and mortality. Whereas the untangling of temperature from other seasonal effects on hydration warrants further study, moderately increased water intake constitutes a feasible intervention to lower vasopressin and might mitigate adverse health effects of both moderately cold and hot outdoor temperatures. FUNDING: Swedish Research Council, Å Wiberg, M Stephen, A Påhlsson, Crafoord and Swedish Heart-Lung Foundations, Swedish Society for Medical Research and Swedish Society of Medicine.

Copeptin is associated with microalbuminuria and renal function in the general Japanese population.

An association between copeptin (precursor molecule of arginine vasopressin) and markers for renal function has been reported, but data on the Japanese population has been limited. In this study, we investigated whether elevated copeptin levels are associated with microalbuminuria and renal dysfunction in the general Japanese population. A total of 1,262 participants (842 female and 420 male) were enrolled. Multiple regression analysis was performed to assess the association of copeptin levels (logarithm) with estimated glomerular filtration rate (eGFR) and the urine albumin-to-creatinine ratio (UACR) after adjusting for age, BMI, and lifestyle variables. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression methods in which chronic kidney disease (CKD) was the dependent variable. The copeptin levels differed significantly with sex, but were not found to be related to age or the span of time from preceding meal to blood sampling. In female participants, copeptin level was negatively correlated with eGFR (beta = -0.100, p-value = 0.006) and positively correlated with UACR (beta = 0.099, p-value = 0.003). In male participants, a negative correlation (beta = -0.140, p-value = 0.008) was observed for eGFR. In both females and males, those with high copeptin levels had more than double the ORs of CKD (OR = 2.1-2.9) adjusted for CKD-related factors. The present study found elevated copeptin levels to be associated with renal function loss in the Japanese population and microalbuminuria in female. Moreover, it was evident that high copeptin levels are associated with CKD. These results suggest that copeptin could be considered a marker of renal function.

Serum Copeptin in Cardiooncology Practice: Review of Pathophysiological and Clinical Implications.

In cardiooncology practice, "early cardiotoxicity" refers to an emerging subclinical myocardial dysfunction/injury in response to certain chemotherapeutic regimens. This condition can progress to overt cardiotoxicity in time and hence warrants proper and timely diagnostic and preventive strategies. Current diagnostic strategies for "early cardiotoxicity" are largely based on conventional biomarkers and certain echocardiographic indices. However, a significant gap still exists in this setting, warranting further strategies to improve diagnosis and overall prognosis in cancer survivors. Copeptin (surrogate marker of the arginine vasopressine axis) might serve as a promising adjunctive guide for the timely detection, risk stratification, and management of early cardiotoxicity on top of conventional strategies largely due to its multifaceted pathophysiological implications in the clinical setting. This work aims to focus on serum copeptin as a marker of "early cardiotoxicity" and its general clinical implications in patients with cancer.

Changed serum levels of CD62E+, angiotensin II and copeptin in patients with chronic insomnia disorder: a link between insomnia and stroke?

BACKGROUND: Epidemiological and observational clinical studies have found that insomnia is a risk factor for stroke and that, accordingly, insomnia is likely to cause changes of stroke-related biomarkers. There is substantial evidence that stroke is closely related to endothelial dysfunction and hypertension. The aim of this study is to investigate whether there is alteration of endothelial dysfunction (CD62E+) and hypertension (angiotensin II and copeptin) biomarkers in patients with chronic insomnia disorder (CID). METHODS: The CID patients (N = 54) and the good sleepers (GS, N = 32) were enrolled. Pittsburgh sleep quality index (PSQI), pre-sleep arousal scale (PSAS) and polysomnography were used to assess their sleep and neuropsychological function. Serum levels of CD62E+, angiotensin II and copeptin were determined using a quantitative sandwich ELISA. RESULTS: The CID group had higher serum levels of CD62E+, angiotensin II, and copeptin than the GS group. After controlling for sex, age, depression and apnea-hypopnea index, the partial correlation analysis revealed that the levels of CD62E+ and copeptin correlated positively with the PSAS score and negatively with the objective sleep quality. Angiotensin II levels negatively correlated with objective sleep onset latency. Moreover, there was a positive correlation between CD62E+ and angiotensin II. Principal components analysis revealed that CD62E+ and copeptin had a substantial correlation with parameters of subjective and objective sleep. CONCLUSION: Patients with CID exhibit endothelial activation, over-activated renin-angiotensin system and increased sympathetic excitability, as indicated by increased serum levels of CD62E+, angiotensin II and copeptin, with linking to poor sleep quality.

Biomarkers-in-Cardiology 8 RE-VISITED-Consistent Safety of Early Discharge with a Dual Marker Strategy Combining a Normal hs-cTnT with a Normal Copeptin in Low-to-Intermediate Risk Patients with Suspected Acute Coronary Syndrome-A Secondary Analysis of the Randomized Biomarkers-in-Cardiology 8 Trial.

Regarding the management of suspected Non-ST-segment-elevation acute coronary syndrome (ACS), the main Biomarker-in-Cardiology (BIC)-8 randomized controlled trial study had reported non-inferiority for the incidence of major adverse cardiac events at 30 days in the Copeptin group (dual marker strategy of copeptin and hs-cTnT at presentation) compared to the standard process (serial hs-cTnT testing). However, in 349 (38.7%) of the 902 patients, high-sensitivity cardiac troponin was not available for the treating physicians. High sensitivity cardiac troponin T was re-measured from thawed blood samples collected at baseline. This cohort qualified for a re-analysis of the 30-day incidence rate of MACE (death, survived cardiac death, acute myocardial infarction, re-hospitalization for acute coronary syndrome, acute unplanned percutaneous coronary intervention, coronary bypass grafting, or documented life-threatening arrhythmias), or components of the primary endpoint including death or death/MI. After re-measurement of troponin and exclusion of 9 patients with insufficient blood sample volume, 893 patients qualified for re-analysis. A total of 57 cases were detected with high sensitivity cardiac troponin T ≥ 14 ng/L who had been classified as "troponin negative" based on a conventional cardiac troponin T or I < 99th percentile upper limit of normal. Major adverse cardiac events rates after exclusion were non-inferior in the Copeptin group compared to the standard group (4.34% (95% confidence intervals 2.60-6.78%) vs. 4.27% (2.55-6.66%)). Rates were 53% lower in the per-protocol analysis (HR 0.47, 95% CI: 0.18-1.15, p = 0.09). No deaths occurred within 30 days in the discharged low risk patients of the Copeptin group. Copeptin combined with high sensitivity cardiac troponin is useful for risk stratification and allows early discharge of low-to-intermediate risk patients with suspected acute coronary syndrome is as safe as a re-testing strategy at 3 h or later.

Improvement of outcome prediction of hospitalized patients with COVID-19 by a dual marker strategy using high-sensitive cardiac troponin I and copeptin.

BACKGROUND: COVID-19 has been associated with a high prevalence of myocardial injury and increased cardiovascular morbidity. Copeptin, a marker of vasopressin release, has been previously established as a risk marker in both infectious and cardiovascular disease. METHODS: This prospective, observational study of patients with laboratory-confirmed COVID-19 infection was conducted from June 6th to November 26th, 2020 in a tertiary care hospital. Copeptin and high-sensitive cardiac troponin I (hs-cTnI) levels on admission were collected and tested for their association with the primary composite endpoint of ICU admission or 28-day mortality. RESULTS: A total of 213 eligible patients with COVID-19 were included of whom 55 (25.8%) reached the primary endpoint. Median levels of copeptin and hs-cTnI at admission were significantly higher in patients with an adverse outcome (Copeptin 29.6 pmol/L, [IQR, 16.2-77.8] vs 17.2 pmol/L [IQR, 7.4-41.0] and hs-cTnI 22.8 ng/L [IQR, 11.5-97.5] vs 10.2 ng/L [5.5-23.1], P < 0.001 respectively). ROC analysis demonstrated an optimal cut-off of 19.3 pmol/L for copeptin and 16.8 ng/L for hs-cTnI and an increase of either biomarker was significantly associated with the primary endpoint. The combination of raised hs-cTnI and copeptin yielded a superior prognostic value to individual measurement of biomarkers and was a strong prognostic marker upon multivariable logistic regression analysis (OR 4.274 [95% CI, 1.995-9.154], P < 0.001). Addition of copeptin and hs-cTnI to established risk models improved C-statistics and net reclassification indices. CONCLUSION: The combination of raised copeptin and hs-cTnI upon admission is an independent predictor of ICU admission or 28-day mortality in hospitalized patients with COVID-19.

Increased Circulating Copeptin Levels Are Associated with Vaso-Occlusive Crisis and Right Ventricular Dysfunction in Sickle Cell Anemia.

OBJECTIVE: Vaso-occlusive crisis (VOC) is a common clinical manifestation of sickle cell anemia (SCA) and is associated with increased proinflammatory mediators. Copeptin is the C-terminal part of the prohormone for provasopressin and seems clinically relevant in various clinical conditions. Right ventricular (RV) dysfunction significantly appears in SCA patients due to pulmonary hypertension. This study aimed to investigate the association of copeptin levels in VOC patients and evaluate RV dysfunction. MATERIALS AND METHODS: A total of 108 patients were enrolled in the study. Twenty-eight SCA patients in steady state (30.2 ± 0.9 years), 25 SCA patients in VOC (36.8 ± 11.8 years), and 55 healthy individuals (31.9 ± 9.4 years) with HbAA genotype were included. Clinical, echocardiographic, and laboratory data were recorded. ELISA was used for the determination of serum levels of copeptin. RESULTS: VOC patients had significantly higher copeptin level compared both with controls and SCA subjects in steady state (22.6 ± 13.0 vs. 11.3 ± 5.7 pmol/L, 22.6 ± 13.0 vs. 12.4 ± 5.8 pmol/L, p = 0.009 for both). Additionally, the copeptin level was significantly higher in SCA patients with RV dysfunction than those without RV dysfunction (23.2 ± 12.2 vs. 15.3 ± 9.5 pmol/L, p = 0.024). Multiple logistic regression analysis revealed that high-sensitivity C-reactive protein and copeptin levels were found to be associated with VOC. CONCLUSION: This study showed that copeptin and hs-CRP levels were increased in patients with VOC, and it was found that RV dysfunction was more common in SCA patients with VOC than in the control group. Copeptin can be considered for use as a potential biomarker in predicting VOC crisis in SCA patients and in the early detection of patients with SCA who have the potential to develop RV dysfunction.

Copeptin: Prognostic Relevance as a Perioperative Marker in Pediatric Cardiac Surgery.

BACKGROUND: Copeptin is a cleavage product of vasopressin. This study aimed to figure out if copeptin would be a suitable biomarker in patients with congenital heart disease in the postoperative course. METHODS: The primary outcome endpoint of this study was the change in copeptin concentration perioperatively in patients with congenital heart disease after surgery, with the use of a cardiopulmonary bypass. Three blood samples were taken from 81 patients up to 6 years of age in order to evaluate changes in copeptin concentration. RESULTS: Significant increase of copeptin concentration was shown between the first and second blood draws as well as between the first and third blood draws (Ps < .001). Additionally, positive and significant correlations (r ≥ .27) between the cardiopulmonary bypass times, The Society of Thoracic Surgeons and European Association for Cardio-Thoracic Surgery mortality category, the inotropic score, the duration of mechanical ventilation, the length of stay at the intensive care unit (ICU), the length of stay at the hospital, and the preoperative as well as the ICU copeptin levels were found. CONCLUSIONS: Copeptin showed a tendency to predict the clinical outcome of patients after congenital heart surgery. Patients with higher copeptin levels underwent more complex procedures, had longer cardiopulmonary bypass times, required more catecholamine support, needed longer time of invasive ventilation, and had longer overall stay and ICU stay.

Investigation of possible underlying mechanisms behind water-induced glucose reduction in adults with high copeptin.

Elevated copeptin, a surrogate marker of vasopressin, is linked to low water intake and increased diabetes risk. Water supplementation in habitual low-drinkers with high copeptin significantly lowers both fasting plasma (fp) copeptin and glucose. This study aims at investigating possible underlying mechanisms. Thirty-one healthy adults with high copeptin (> 10.7 pmol·L-1 (men), > 6.1 pmol-1 (women)) and 24-h urine volume of < 1.5L and osmolality of > 600 mOsm·kg-1 were included. The intervention consisted of addition of 1.5 L water daily for 6 weeks. Fp-adrenocorticotropic hormone (ACTH), fp-cortisol, 24-h urine cortisol, fasting and 2 h (post oral glucose) insulin and glucagon were not significantly affected by the water intervention. However, decreased (Δ baseline-6 weeks) fp-copeptin was significantly associated with Δfp-ACTH (r = 0.76, p < 0.001) and Δfp-glucagon (r = 0.39, p = 0.03), respectively. When dividing our participants according to baseline copeptin, median fp-ACTH was reduced from 13.0 (interquartile range 9.2-34.5) to 7.7 (5.3-9.9) pmol L-1, p = 0.007 in the top tertile of copeptin, while no reduction was observed in the other tertiles. The glucose lowering effect from water may partly be attributable to decreased activity in the hypothalamic-pituitary-adrenal axis.ClinicalTrials.gov: NCT03574688.

Community evaluation of glycoproteomics informatics solutions reveals high-performance search strategies for serum glycopeptide analysis.

Glycoproteomics is a powerful yet analytically challenging research tool. Software packages aiding the interpretation of complex glycopeptide tandem mass spectra have appeared, but their relative performance remains untested. Conducted through the HUPO Human Glycoproteomics Initiative, this community study, comprising both developers and users of glycoproteomics software, evaluates solutions for system-wide glycopeptide analysis. The same mass spectrometrybased glycoproteomics datasets from human serum were shared with participants and the relative team performance for N- and O-glycopeptide data analysis was comprehensively established by orthogonal performance tests. Although the results were variable, several high-performance glycoproteomics informatics strategies were identified. Deep analysis of the data revealed key performance-associated search parameters and led to recommendations for improved 'high-coverage' and 'high-accuracy' glycoproteomics search solutions. This study concludes that diverse software packages for comprehensive glycopeptide data analysis exist, points to several high-performance search strategies and specifies key variables that will guide future software developments and assist informatics decision-making in glycoproteomics.

Parathyroid Hormone Resistance and Autoantibodies to the PTH1 Receptor.

We describe two cases of acquired parathyroid hormone (PTH) resistance consequent to the development of serum PTH type 1 receptor (PTH1R) autoantibodies, which block PTH binding and signaling. Both cases were associated with other autoimmune manifestations, and one case was associated with atypical membranous glomerulonephritis. In vitro binding and signaling assays identified the presence of PTH1R-blocking IgG autoantibodies, which were not present in serum samples from patients with other renal or autoimmune disorders. (Funded by the Intramural Research Programs of the National Institute of Diabetes and Digestive and Kidney Diseases and others.).

Fabrication of hydrophilic zwitterionic microspheres via inverse suspension polymerization for the enrichment of N-glycopeptides.

A kind of zwitterionic microsphere was prepared via one-step inverse suspension polymerization employing 3-[N,N-dimethyl-[2-(2-methylpropyl-2-enyloxy) ethyl] ammonium] propane-1-sulfonate (MSA) and N,N-methylene bisacrylamide (BIS) as the precursors. The preparation conditions were carefully investigated and optimized by regulating the content of total monomers, ratio of MSA to BIS, ratio of water to oil, and content of stabilizer. The properties of microspheres were characterized by helium ion microscopy (HIM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption measurement, and water contact angle measurement. The particle size of resulting polydisperse microspheres ranged from 15-25 µm, exhibiting high specific surface area of 138 m2 g-1. Owing to great hydrophilicity, the resulting zwitterionic microspheres could be directly used as hydrophilic interaction chromatography (HILIC) sorbent to enrich glycopeptides from biosamples without any chemical modification. A total of 19 N-glycopeptides was enriched from 10 µg of IgG digest. Besides, up to 383 N-glycopeptides and 224 N-glycosylation sites were unambiguously identified from 2 µL of human serum digest by cLC-MS/MS after enrichment with zwitterionic microspheres, indicating their great enrichment performance to N-glycopeptides. The approach of preparing hydrophilic zwitterionic microspheres contains only one synthesis reaction and is suitable for large-scale preparation.

Copeptin and insulin-like growth factor-1 predict long-term outcomes after aneurysmal subarachnoid hemorrhage: A large prospective cohort study.

OBJECTIVE: The predictive roles of copeptin and insulin-like growth factor-1 (IGF-1) in aneurysmal subarachnoid hemorrhage (aSAH) remain controversial. We aimed to define the relationship between copeptin and IGF-1 levels and functional outcome as well as quality of life (QoL) after aSAH. METHODS: Patients with aSAH were prospectively enrolled in a tertiary university hospital. Controls were sex- and age-matched healthy subjects. Plasma concentrations of copeptin and IGF-1 were measured on admission. Demographics and clinical, radiological and laboratory characteristics of the patients were collected. Favorable functional outcome was defined as modified Rankins≤2, and QoL was evaluated by the 36-Item Short Form Health Survey (SF-36) 1 year after aSAH. Uni- and multivariable analyses were performed. RESULTS: One hundred eighteen patients were eligible, with 122 healthy controls were included in this study. Plasma copeptin levels were significantly higher and plasma IGF-1 was lower in patients than in controls. Both copeptin (adjusted HR 4.143 [1.120-15.328], p = 0.033) and IGF-1 levels (adjusted HR 0.089 [0.013-0.602], p = 0.013) were positively associated with 1-year mortality, while only single copeptin and IGF-1 concentrations were independent predictors of poor functional outcome and QoL, respectively. CONCLUSIONS: Plasma copeptin and IGF-1 levels are abnormal in patients with acute aSAH, and this may reliably predict long-term mortality, functional outcome and QoL.

The additive value of copeptin for early diagnosis and prognosis of acute coronary syndromes.

BACKGROUND: One promising biomarker that has received substantial interest for the evaluation of suspected acute coronary syndromes (ACS) is copeptin. Therefore, our goal was to assess the additive value of copeptin for early diagnosis and prognosis of Non-ST segment acute coronary syndromes (NSTE-ACS). METHODS: The study included ninety patients with suspected ACS. Patients with typical ischemic chest pain within six hours of symptom onset and without ST-segment elevation on electrocardiograph (ECG) were included. In addition to cardiac troponin I (cTnI), copeptin was assayed from venous blood samples obtained on admission, followed by serial troponin measurements six and twelve hours later. One year follow-up was performed for any major adverse cardiac events (MACEs) including cardiac death, re-infarction, re- hospitalization for ischemic events, heart failure, stroke and target lesion revascularization (TLR). RESULTS: Of seventy nine patients included in the final analysis, Forty (50.6%) were diagnosed as unstable angina (UA), while thirty nine (49.4%) had a non-ST elevation myocardial infarction (NSTEMI). Copeptin level on admission was significantly higher among NSTEMI patients than those with UA. With regard to the correlation analyses, copeptin was positively correlated with each of, Global Registry of Acute Coronary Events (GRACE), Thrombolysis In Myocardial Infarction (TIMI) and synergy between percutaneous coronary intervention with taxus and cardiac surgery (SYNTAX) scores. The sensitivity and negative predictive value (NPV) of the combination of admission copeptin and cTn-I were 100% and 100%, respectively, versus 57% and 70%, respectively, with admission of cTn-I alone. The area under curve (AUC) of the combination of copeptin and cTn-I was (0.975, p < 0.001) and was significantly higher than the AUC of cTn-I alone (0.888, p < 0.001). Admission copeptin was an independent predictor for MACEs by multiple regression analysis (OR: 0.01, 95% CI: 0.0-0.8, P = 0.04). High values of copeptin had the highest rate of MACEs and coronary revascularization during one year of follow up. CONCLUSION: The combination of copeptin and conventional troponin I aids in early rule out of NSTEMI virtually independent of chest pain onset (CPO) with high NPV in patients presenting within three hours from chest pain onset with excellent prognostic value for risk stratification and prediction of MACEs.

Tubular injury in diabetic ketoacidosis: Results from the diabetic kidney alarm study.

OBJECTIVE: Glomerular injury is a recognized complication of diabetic ketoacidosis (DKA), yet the tubular lesions are poorly understood. The aim of this prospective study was to evaluate the presence and reversibility of tubular injury during DKA in children with type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: Blood and urine samples were collected from 40 children with DKA (52% boys, mean age 11 ± 4 years, venous pH 7.2 ± 0.1, glucose 451 ± 163 mg/dL) at three timepoints: 0-8 and 12-24 h after starting insulin, and 3 months after discharge. Mixed-effects models evaluated the changes in tubular injury markers over time (neutrophil gelatinase-associated lipocalin [NGAL], kidney injury molecule 1 [KIM-1], and interleukin 18 [IL-18]). We also evaluated the relationships among the tubular injury biomarkers, copeptin, a vasopressin surrogate, and serum uric acid (SUA). RESULTS: Serum NGAL, KIM-1, and IL-18 were highest at 0-8 h (306.5 ± 45.9 ng/mL, 128.9 ± 10.1 pg/mL, and 564.3 ± 39.2 pg/mL, respectively) and significantly decreased over 3 months (p = 0.03, p = 0.01, and p < 0.001, respectively). There were strong relationships among increases in copeptin and SUA and rises in tubular injury biomarkers. At 0-8 h, participants with acute kidney injury (AKI) [17%] showed significantly higher concentrations of tubular injury markers, copeptin, and SUA. CONCLUSIONS: DKA was characterized by tubular injury, and the degree of injury associated with elevated copeptin and SUA. Tubular injury biomarkers, copeptin and SUA may be able to predict AKI in DKA.

Changes in copeptin levels before and 3 months after transsphenoidal surgery according to the presence of postoperative central diabetes insipidus.

Copeptin levels reflect arginine vasopressin (AVP) release from the hypothalamus. Pituitary surgery often impairs AVP release and results in central diabetes insipidus (CDI). Here, we aimed to investigate how serum copeptin level changes 3 months after pituitary surgery and whether it has a diagnostic value for postoperative permanent CDI. Consecutive patients who underwent endoscopic transsphenoidal surgery at a single tertiary hospital were recruited. Serum copeptin levels were measured preoperatively and 3 months postoperatively. Among 88 patients, transient and permanent CDI occurred in 17 (19.3%) and 23 (26.1%), respectively. Three-month postoperative copeptin levels significantly declined from preoperative levels in permanent CDI group (P < 0.001, percentage difference = - 42.2%) and also in the transient CDI group (P = 0.002, - 27.2%). Three months postoperative copeptin level < 1.9 pmol/L under normal serum sodium levels was the optimal cutoff value for diagnosing permanent CDI with an accuracy of 81.8%, while 3-month postoperative copeptin level ≥ 3.5 pmol/L excluded the CDI with a negative predictive value of 100%. Conclusively, 3 months postoperative copeptin levels significantly decreased from preoperative levels in the transient CDI group as well as the permanent CDI group. Three-month postoperative copeptin levels ≥ 3.5 pmol/L under normal serum sodium levels may be diagnostic for excluding postoperative CDI.

Can treatment response to SGLT2-inhibitors in syndrome of inappropriate antidiuresis be predicted by copeptin, natriuretic peptides and inflammatory markers?

PURPOSE: The syndrome of inappropriate antidiuresis (SIAD) is the main cause of hyponatremia and the SGLT2-inhibitor empagliflozin is a promising new treatment option. A biomarker predicting treatment response could optimize treatment success. MATERIALS AND METHODS: Secondary analysis of a trial including 84 hospitalized patients with SIAD-induced hyponatremia. Patients were randomized to four days of treatment with empagliflozin 25 mg/d (n = 43) or placebo (n = 41) with both groups receiving fluid restriction <1000 ml/d. Baseline levels of copeptin, the natriuretic peptides MR-proANP and NT-proBNP and C-reactive protein (CRP) were evaluated as predictors for treatment response defined as absolute sodium change, using linear regression models. Additionally, urinary sodium was assessed as predictor for non-response to fluid restriction alone by constructing the receiver-operating characteristic (ROC) curve. RESULTS: No clinically relevant predictive value for treatment response to empagliflozin could be found for copeptin, MR-proANP, NT-proBNP or CRP. A urinary sodium cut-off of >76 mmol/l led to a specificity of 91.7% [95% confidence interval (CI): 75%, 100%] and sensitivity of 51.9% [33.3%, 70.4%] to predict non-response to fluid restriction alone. CONCLUSIONS: Based on our data, no biomarker could be identified as predictor for treatment response to empagliflozin. Urinary sodium was confirmed as a good marker for non-response to fluid restriction in SIAD patients. Clinical trial registration: ClinicalTrials.gov (Number: NCT02874807).

Glycan biomarkers of autoimmunity and bile acid-associated alterations of the human glycome: Primary biliary cirrhosis and primary sclerosing cholangitis-specific glycans.

We have recently introduced multiple reaction monitoring (MRM) mass spectrometry as a novel tool for glycan biomarker research and discovery. Herein, we employ this technique to characterize the site-specific glycan alterations associated with primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Glycopeptides associated with disease severity were also identified. Multinomial regression modelling was employed to construct and validate multi-analyte diagnostic models capable of accurately distinguishing PBC, PSC, and healthy controls from one another (AUC = 0.93 ± 0.03). Finally, to investigate how disease-relevant environmental factors can influence glycosylation, we characterized the ability of bile acids known to be differentially expressed in PBC to alter glycosylation. We hypothesize that this could be a mechanism by which altered self-antigens are generated and become targets for immune attack. This work demonstrates the utility of the MRM method to identify diagnostic site-specific glycan classifiers capable of distinguishing even related autoimmune diseases from one another.

Copeptin as a novel biomarker of cardiometabolic syndrome.

Arginine vasopressin (AVP), which is also called antidiuretic hormone (ADH), is a neurohormone synthetized from a pre-pro-hormone precursor in the supraoptic and paraventricular nuclei of the hypothalamus in response to increased plasma osmolality and decreased blood volume. AVP exerts several effects by binding to three different receptors: V1aR, V1bR, and V2R. In recent years, it has been suggested that increased plasma concentration of AVP may play a causal role in the development of type 2 diabetes, the metabolic syndrome, renal dysfunction and cardiovascular disease by influencing glucose homeostasis and lipid metabolism through several possible mechanisms involving V1aR and V1bR. V1aR located in the liver is involved in hepatic glycogenolysis and gluconeogenesis. V1bR, found in the pituitary gland and pancreas, mediates secretion of adrenocorticotrophic hormone (ACTH), insulin, and glucagon. However, AVP's clinical use as a biomarker is limited due to its short half-life in plasma (16-20 minutes), small size, and poor stability, which make direct measurement difficult. Copeptin, the biologically inactive, stable, C-terminal part of pro-vasopressin, is co-secreted with AVP in equimolar amounts and thus is considered an adequate and clinically useful surrogate marker of AVP. The aim of this review is to assess the current state of knowledge about the potential role of copeptin as a novel biomarker of cardiometabolic syndrome on the basis of recent scientific literature published up to December 2020 and searches of the PubMed, Google Scholar, and Web of Science databases.

Glutathione-functionalized two-dimensional cobalt sulfide nanosheets for rapid and highly efficient enrichment of N-glycopeptides.

Protein glycosylation plays pivotal role in a variety of biological processes and has association with many diseases. The highly efficient glycopeptide enrichment is essential for the mass spectrometry-based glycoproteome research to reduce interference from non-glycopeptides. In this study, novel glutathione-functionalized two-dimensional cobalt sulfide nanosheets (Co-S@Au-GSH) were synthesized for rapid and highly effective enrichment of glycopeptides. By using this nanomaterial, 34 and 21 N-glycopeptides were effectively captured from human serum immunoglobulin G (IgG) and horseradish peroxidase (HRP) digests, respectively. In addition, the Co-S@Au-GSH showed remarkable performance in N-glycopeptide extraction with high selectivity (HRP: BSA = 1:500), low limit of detection (0.5 fmol/µL), high binding capacity (150 mg/g), good reusability, and great robustness. Moreover, it was successfully applied in complex serum samples, demonstrating its excellent enrichment performance. These results indicated that this nanomaterial has great potential in complicated practice samples in glycoproteome determination.