Copeptin: clinical use of a new biomarker

Role of Copeptin in Predicting Postoperative Hyponatremia and Hypernatremia in Patients Undergoing Endoscopic Pituitary Adenoma Surgery

BACKGROUND AND OBJECTIVES

Arginine vasopressin (AVP) is an important hormone responsible for maintaining sodium homeostasis after pituitary surgery. The measurement of AVP levels is difficult because of its short half-life (t 1/2 ). Copeptin is a preprohormone of AVP, and it is a more stable peptide, which can be used as surrogate marker for AVP. This study aims to assess the role of copeptin as a predictor of postoperative hyponatremia and hypernatremia in patients undergoing endoscopic pituitary adenoma surgery.

METHODS

This prospective study included 50 patients who underwent endoscopic pituitary adenoma surgery. Serum copeptin levels of these patients were assessed (1) preoperatively (C1), (2) at extubation (C2), and (3) postoperative day 4 (C3). Perioperative data regarding fluid and sodium balance were collected from patients. Statistical analysis was done using the above data.

RESULTS

The copeptin values were assessed against the sodium disturbances. 100% of patients who developed transient diabetes insipidus had a relative decrease in C2 from C1 ( P - .0002). 88% of patients who developed early hyponatremia had a relative increase in C2 as compared with C1 ( P < .01). 75% of patients who developed delayed hyponatremia had a relative increase in C3 as compared with C1 ( P = .003).

CONCLUSION

A relative increase or decrease in early change in copeptin (C2-C1) can predict development of early hyponatremia or transient central diabetes insipidus, respectively. A relative increase in delayed change in copeptin (C3-C1) can predict development of delayed hyponatremia.

Copeptin as a potential biomarker of chronic kidney disease to predict the disease progression in children with chronic kidney disease

Background

Biomarkers to predict the onset and progression of chronic kidney disease (CKD) in children are lacking, and no such definite biomarkers have been implicated in the diagnosis of CKD. We conducted this study to evaluate copeptin as a CKD marker and predict the disease progression by estimating the copeptin levels at baseline and 12 months follow-up in children with CKD stage 2 and above.

Materials and Methods

This prospective single-centre cohort study was conducted in children under 14 years with CKD stages 2-4. Blood and urine samples were collected at enrolment and 1-year follow-up for routine investigations and serum copeptin, cystatin C and urinary neutrophil gelatinase-associated lipocalcin (uNGAL) estimation.

Results

A total of 110 children (60 cases and 50 controls) were enrolled in the study. The mean estimated glomerular filtration rate (eGFR) of cases was 58.3 ± 18.7 ml/min/1.73 m2. Among the cases, there was a significant rise in the serum copeptin levels from baseline 483.08 ± 319.2 pg/ml to follow-up at 1 year, that is, 1046.82 ± 823.53 pg/ml (P < 0.0001). A significant difference was noted in the baseline values of serum cystatin C, that is, 1512.98 ± 643.77 ng/ml and 719.68 ± 106.96 ng/ml (P < 0.0001), and uNGAL, that is, 13.53 ± 11.72 and 1.76 ± 2.37 ng/ml (P < 0.0001) between the cases and controls. There was no significant correlation (correlation coefficient = 0.10) between change in eGFR and copeptin levels during 12 months of follow-up.

Conclusion

No significant correlation was found between the change in eGFR and copeptin levels during 12 months of follow-up. This can be due to the slow deterioration of renal functions, as most of the cases had underlying congenital anomalies of the kidney and urinary tract (CAKUT), which is known to have a slow progression of CKD and a small sample size.

Neurophysin I is an analytically robust surrogate biomarker for oxytocin

Oxytocin is a pleiotropic neuropeptide that plays roles in biological processes ranging from birth, lactation, and social bonding to immune function, cardiovascular repair, and regulation of appetite. Although measurements of endogenous oxytocin concentrations have been performed for more than 50 years, the ability to measure oxytocin accurately poses notable challenges. One potential solution for overcoming these challenges involves measurement of oxytocin's carrier molecule - neurophysin I (NP-1) - as a surrogate biomarker. NP-1 is secreted in equimolar concentrations with oxytocin but has a longer half-life, circulates in higher concentrations, and can be measured using a sandwich immunoassay. We report experiments that 1) analytically validate a commercially available NP-1 sandwich immunoassay for use with human plasma and urine samples, 2) confirm the specificity of this assay, based on detection of NP-1 in plasma from wild-type but not oxytocin knockout mice, 3) demonstrate that NP-1 concentrations are markedly elevated in late pregnancy, consistent with studies showing substantial increases in plasma oxytocin throughout gestation, and 4) establish strong correlation between NP-1 and plasma oxytocin concentrations when oxytocin is measured in extracted (but not non-extracted) plasma. The NP-1 assay used in this study has strong analytical properties, does not require time-intensive extraction protocols, and the assay itself can be completed in < 2 h (compared to 16-24 h for a competitive oxytocin immunoassay). Our findings suggest that much like copeptin has become a useful surrogate biomarker in studies of vasopressin, measurements of NP-1 have similar potential to advance oxytocin research.

Very elevated serum copeptin concentrations occur in a subset of healthy children in the minutes after phlebotomy

OBJECTIVES

Although AVP and its surrogate, copeptin, are mainly regulated by osmotic and volume stimuli, their secretion is also elicited by stress and growth hormone (GH) stimulating agents. The aim of this report is to describe unusual patterns of copeptin response in a subset of children undergoing GH stimulation tests (GH-ST).

METHODS

We conducted a secondary analysis of a cohort of 93 healthy short children with no polydipsia, polyuria or fluid/electrolyte abnormalities, undergoing GH-ST with intravenous arginine, insulin, oral clonidine, or L-Dopa/carbidopa in various combinations. Serum copeptin concentrations were measured 1-3 min after phlebotomy (0 min) and at 60, 90, 120 min during GH-ST.

RESULTS

In 85 subjects (normal response group, NRG) serum copeptin concentrations increased from a 0 min median of 9 pmol/L (IQR 6, 11.5) (all values ≤21) to a median peak between 60 and 120 min of 22 (IQR15, 38) pmol/L, which varied depending on the stimulating agent. Conversely, in the eight outliers, copeptin concentrations decreased gradually from a median of 154 (IQR 61, 439) pmol/L (all ≥40 pmol/L) to values as low as 14 % of the basal value, by 120 min. Test-associated anxiety was described in 17 subjects in the NRG (20 %) and five of the outliers (63 %).

CONCLUSIONS

A distinctive pattern of very elevated serum copeptin concentrations occurred in 9 % of children undergoing GH-ST, similar to reports in previous pediatric studies. Etiology may include pain or stress of phlebotomy. This phenomenon should be recognized for proper interpretation of copeptin values in children.

High level of psychological stress in COVID-19 recovered individuals: role of copeptin as a potential biomarker

Background

Study aimed to assess stress in COVID-19 recovered individuals using a validated questionnaire PSS-10 score and stress biomarkers - salivary cortisol and serum copeptin.

Methods

A total of 83 subjects of which 54 subjects (66.3%) who were hospitalized were recruited 8-20 weeks following recovery from COVID-19. Stress was assessed by PSS-10 stress-scale after a mean duration of 14.5 weeks after recovery. Sixty-eight subjects (81.9%) had new or persistent symptoms after recovery. Subjects were divided into two groups on the basis of PSS score; mild stress (PSS:0-13) and moderate to severe stress (PSS:>14) and levels of biomarkers (serum copeptin, DHEAS and salivary cortisol) were compared in the two groups.

Results

Forty-four subjects (53%) had moderate to severe stress and 39 subjects (47%) had mild stress. Subjects with post COVID symptoms had significantly higher stress levels as compared to subjects who were asymptomatic [15 vs. 9; p = 0.003]. Serum copeptin levels were significantly higher among subjects with moderate to severe stress as compared to those with mild stress [0.41 vs. 0.67 ng/mL; p = 0.031]. Subjects with moderate to severe stress had higher median salivary cortisol compared to subjects with mild stress [1.03 vs. 1.44 nmol/L; p = 0.448].

Conclusion

Our study demonstrated moderate to severe stress in over half and some level of stress in nearly all COVID recovered individuals even after 3 months. Serum copeptin was found to be a useful biomarker to objectively measure stress in these subjects.

Multitissue Circadian Proteome Atlas of WT and Per1-/-/Per2-/- Mice

The molecular basis of circadian rhythm, driven by core clock genes such as Per1/2, has been investigated on the transcriptome level, but not comprehensively on the proteome level. Here we quantified over 11,000 proteins expressed in eight types of tissues over 46 h with an interval of 2 h, using WT and Per1/Per2 double knockout mouse models. The multitissue circadian proteome landscape of WT mice shows tissue-specific patterns and reflects circadian anticipatory phenomena, which are less obvious on the transcript level. In most peripheral tissues of double knockout mice, reduced protein cyclers are identified when compared with those in WT mice. In addition, PER1/2 contributes to controlling the anticipation of the circadian rhythm, modulating tissue-specific cyclers as well as key pathways including nucleotide excision repair. Severe intertissue temporal dissonance of circadian proteome has been observed in the absence of Per1 and Per2. The γ-aminobutyric acid might modulate some of these temporally correlated cyclers in WT mice. Our study deepens our understanding of rhythmic proteins across multiple tissues and provides valuable insights into chronochemotherapy. The data are accessible at https://prot-rhythm.prottalks.com/.

Predicting autosomal dominant polycystic kidney disease progression: review of promising Serum and urine biomarkers

Autosomal dominant polycystic kidney disease (ADPKD) is one of the leading causes of end-stage renal disease. In spite of the recent tremendous progress in the understanding of ADPKD pathogenesis, the molecular mechanisms of the disease remain incompletely understood. Considering emerging new targeted therapies for ADPKD, it has become crucial to disclose easily measurable and widely available biomarkers for identifying patients with future rapid disease progression. This review encompasses all the research with a shared goal of identifying promising serum or urine biomarkers for predicting ADPKD progression or response to therapy. The rate of the ADPKD progress varies significantly between patients. The phenotypic variability is only partly explained by the underlying genetic lesion diversity. Considering significant decline in kidney function in ADPKD is not usually evident until at least 50% of the parenchyma has been destroyed, conventional kidney function measures, such as glomerular filtration rate (GFR), are not suitable for monitoring disease progression in ADPKD, particularly in its early stages. Since polycystic kidney enlargement usually precedes the decline in GFR, height-adjusted total kidney volume (ht-TKV) has been accepted as an early biomarker for assessing disease severity in ADPKD patients. However, since measuring ht-TKV is time-consuming and observer-dependent, the identification of a sensitive and quickly measurable biomarker is of a great interest for everyday clinical practice. Throughout the last decade, due to development of proteomic and metabolomic techniques and the enlightenment of multiple molecular pathways involved in the ADPKD pathogenesis, a number of urine and serum protein biomarkers have been investigated in ADPKD patients, some of which seem worth of further exploring. These include copeptin, angiotensinogen, monocyte chemoattractant protein 1, kidney injury molecule-1 and urine-to-plasma urea ratio among many others. The aim of the current review is to provide an overview of all of the published evidence on potentially clinically valuable serum and urine biomarkers that could be used for predicting disease progression or response to therapy in patients with ADPKD. Hopefully, this review will encourage future longitudinal prospective clinical studies evaluating proposed biomarkers as prognostic tools to improve management and outcome of ADPKD patients in everyday clinical practice.

Electrolyte Imbalance in Anti-LGI1 Encephalitis: It Is Not All in Your Head

BACKGROUND AND OBJECTIVES

Antileucine-rich glioma-inactivated 1 (anti-LGI1) autoimmune encephalitis was first described in 2010 and is today the most common type of limbic encephalitis. During the course of the disease, 60%-88% of the patients develop hyponatremia. The etiology of the sodium disorder is unclear, often presumed to be the result of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Other electrolyte abnormalities have not been reported in association with anti-LGI1 antibody encephalitis. Due to the presence of hypomagnesemia and hypophosphatemia in our patients, we set out to try to find the expression of LGI1 protein in the kidney as an explanation for these abnormalities.

METHODS

We reviewed the medical files of all patients diagnosed with anti-LGI1 antibody encephalitis, at the Department of Neurology in the Tel Aviv Medical Center between January 2011 and December 2020, exploring for electrolyte abnormalities. Using tissue staining, Western blot, mass spectrometry, and RNA expression techniques, we tried to demonstrate the expression of LGI1 protein in the human kidney.

RESULTS

We identified 15 patients diagnosed with anti-LGI1 antibody encephalitis. Their average age was 65 years (44-80), and 9 were male individuals. Thirteen of the 15 patients (87%) developed varying degrees of hyponatremia. Laboratory studies demonstrated low serum osmolality, low serum blood urea nitrogen, and low uric acid, with a high urinary sodium and inappropriately high urine osmolality, supporting the presumable diagnosis of SIADH. One patient with hyponatremia that was tested, had high levels of copeptin, supporting the diagnosis of SIADH. In addition to hyponatremia, 7 patients (47%) exhibited other electrolyte abnormalities; 5 patients (33%) had overt hypophosphatemia, 4 patients (27%) had overt hypomagnesemia, and 2 other patients (13%) had borderline low magnesium levels. Western blot analysis of human kidney lysate, mass spectrometry, and qRT-PCR failed to demonstrate the expression of LGI1 protein in the kidney.

DISCUSSION

Hyponatremia in patients with anti-LGI1 antibody encephalitis is due to SIADH as previously assumed. Other electrolyte abnormalities such as hypomagnesemia and hypophosphatemia occur in at least 40% of patients and may be another clue for the diagnosis of anti-LGI1 antibody encephalitis. Because we failed to demonstrate LGI1 expression in the kidney, the results of our study suggest that renal losses lead to these disturbances, most probably due to SIADH.

Molecular biomarkers for assessing the heat-adapted phenotype: a narrative scoping review

Heat acclimation/acclimatisation (HA) mitigates heat-related decrements in physical capacity and heat-illness risk and is a widely advocated countermeasure for individuals operating in hot environments. The efficacy of HA is typically quantified by assessing the thermo-physiological responses to a standard heat acclimation state test (i.e. physiological biomarkers), but this can be logistically challenging, time consuming, and expensive. A valid molecular biomarker of HA would enable evaluation of the heat-adapted state through the sampling and assessment of a biological medium. This narrative review examines candidate molecular biomarkers of HA, highlighting the poor sensitivity and specificity of these candidates and identifying the current lack of a single 'standout' biomarker. It concludes by considering the potential of multivariable approaches that provide information about a range of physiological systems, identifying a number of challenges that must be overcome to develop a valid molecular biomarker of the heat-adapted state, and highlighting future research opportunities.

Renal and hypothalamic inflammation in renovascular hypertension: role of afferent renal nerves

Renal denervation (RDN) is a potential therapy for drug-resistant hypertension. However, whether its effects are mediated by ablation of efferent or afferent renal nerves is not clear. Previous studies have implicated that renal inflammation and the sympathetic nervous system are driven by the activation of afferent and efferent renal nerves. RDN attenuated the renal inflammation and sympathetic activity in some animal models of hypertension. In the 2 kidney,1 clip (2K1C) model of renovascular hypertension, RDN also decreased sympathetic activity; however, mechanisms underlying renal and central inflammation are still unclear. We tested the hypothesis that the mechanisms by which total RDN (TRDN; efferent + afferent) and afferent-specific RDN (ARDN) reduce arterial pressure in 2K1C rats are the same. Male Sprague-Dawley rats were instrumented with telemeters to measure mean arterial pressure (MAP), and after 7 days, a clip was placed on the left renal artery. Rats underwent TRDN, ARDN, or sham surgery of the clipped kidney and MAP was measured for 6 wk. Weekly measurements of water intake (WI), urine output (UO), and urinary copeptin were conducted, and urine was analyzed for cytokines/chemokines. Neurogenic pressor activity (NPA) was assessed at the end of the protocol calculated by the depressor response after intraperitoneal injection of hexamethonium. Rats were euthanized and the hypothalamus and kidneys removed for measurement of cytokine content. MAP, NPA, WI, and urinary copeptin were significantly increased in 2K1C-sham rats, and these responses were abolished by both TRDN and ARDN. 2K1C-sham rats presented with renal and hypothalamic inflammation and these responses were largely mitigated by TRDN and ARDN. We conclude that RDN attenuates 2K1C hypertension primarily by ablation of afferent renal nerves which disrupts bidirectional renal neural-immune pathways.NEW & NOTEWORTHY Hypertension resulting from reduced perfusion of the kidney is dependent on renal sensory nerves, which are linked to inflammation in the kidney and hypothalamus. Afferent renal nerves are required for chronic increases in both water intake and vasopressin release observed following renal artery stenosis. Findings from this study suggest an important role of renal sensory nerves that has previously been underestimated in the pathogenesis of 2K1C hypertension.

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.

North African fox genomes show signatures of repeated introgression and adaptation to life in deserts

Elucidating the evolutionary process of animal adaptation to deserts is key to understanding adaptive responses to climate change. Here we generated 82 individual whole genomes of four fox species (genus Vulpes) inhabiting the Sahara Desert at different evolutionary times. We show that adaptation of new colonizing species to a hot arid environment has probably been facilitated by introgression and trans-species polymorphisms shared with older desert resident species, including a putatively adaptive 25 Mb genomic region. Scans for signatures of selection implicated genes affecting temperature perception, non-renal water loss and heat production in the recent adaptation of North African red foxes (Vulpes vulpes), after divergence from Eurasian populations approximately 78 thousand years ago. In the extreme desert specialists, Rueppell's fox (V. rueppellii) and fennec (V. zerda), we identified repeated signatures of selection in genes affecting renal water homeostasis supported by gene expression and physiological differences. Our study provides insights into the mechanisms and genetic underpinnings of a natural experiment of repeated adaptation to extreme conditions.

Apelin-13 as a Potential Biomarker in Critical Illness

BACKGROUND

The adrenocortical system and copeptin as prognostic markers were intensively investigated in critical illness. The potential predictive power of apelin-13 as a biomarker is largely unknown. We aimed to investigate the prognostic role of apelin-13 in relation to free cortisol, aldosterone, CRH, and copeptin in critically ill patients.

METHODS

In this prospective observational study, 124 critically ill patients (64 men, 60 women, median age: 70 (59-78) years) were consecutively enrolled at the time of admission. All routinely available clinical and laboratory parameters were evaluated and correlated to hormonal changes.

RESULTS

Serum apelin-13 was 1161 (617-2967) pg/mL in non-survivors vs. 2477 (800-3531) pg/mL in survivors (p = 0.054). The concentrations of apelin-13 and CRH had strong positive correlations (r = 0.685, p < 0.001) and were significantly higher in surviving non-septic patients (Apelin-13 (pg/mL): 2286 (790-3330) vs. 818 (574-2732) p < 0.05; CRH (pg/mL) 201 (84-317) vs. 89 (74-233) p < 0.05). Apelin-13 and free cortisol were independent determinants of survival in the multivariate Cox regression analysis, while copeptin, CRH, or aldosterone were not.

CONCLUSIONS

Beyond free cortisol, serum apelin-13 may also help refine prognostic predictions in the early phase of critical illness, especially in non-septic patients.

Elevated Copeptin Levels Are Associated with Heart Failure Severity and Adverse Outcomes in Children with Cardiomyopathy

In children with cardiomyopathy, the severity of heart failure (HF) varies. However, copeptin, which is a biomarker of neurohormonal adaptation in heart failure, has not been studied in these patients. In this study, we evaluated the correlation of copeptin level with functional HF grading, B-type natriuretic peptide (BNP), and echocardiography variables in children with cardiomyopathy. Furthermore, we determined if copeptin levels are associated with adverse outcomes, including cardiac arrest, mechanical circulatory support, heart transplant, or death. In forty-two children with cardiomyopathy with a median (IQR) age of 13.1 years (2.5-17.2) and a median follow-up of 2.5 years (2.2-2.7), seven (16.7%) children had at least one adverse outcome. Copeptin levels were highest in the patients with adverse outcomes, followed by the patients without adverse outcomes, and then the healthy children. The copeptin levels in patients showed a strong correlation with their functional HF grading, BNP level, and left ventricular ejection fraction (LVEF). Patients with copeptin levels higher than the median value of 25 pg/mL had a higher likelihood of experiencing adverse outcomes, as revealed by Kaplan-Meier survival analysis (p = 0.024). Copeptin level was an excellent predictor of outcomes, with an area under the curve of 0.861 (95% CI, 0.634-1.089), a sensitivity of 86%, and a specificity of 60% for copeptin level of 25 pg/mL. This predictive value was superior in patients with dilated and restrictive cardiomyopathies (0.97 (CI 0.927-1.036), p < 0.0001, n = 21) than in those with hypertrophic and LV non-compaction cardiomyopathies (0.60 (CI 0.04-1.16), p = 0.7, n = 21).

Assessment of Tissue Expression of the Oxytocin-Vasopressin Pathway in the Placenta of Women with a First-Episode Psychosis during Pregnancy

Psychosis refers to a mental health condition characterized by a loss of touch with reality, comprising delusions, hallucinations, disorganized thought, disorganized behavior, catatonia, and negative symptoms. A first-episode psychosis (FEP) is a rare condition that can trigger adverse outcomes both for the mother and newborn. Previously, we demonstrated the existence of histopathological changes in the placenta of pregnant women who suffer an FEP in pregnancy. Altered levels of oxytocin (OXT) and vasopressin (AVP) have been detected in patients who manifested an FEP, whereas abnormal placental expression of these hormones and their receptors (OXTR and AVPR1A) has been proven in different obstetric complications. However, the precise role and expression of these components in the placenta of women after an FEP have not been studied yet. Thus, the purpose of the present study was to analyze the gene and protein expression, using RT-qPCR and immunohistochemistry (IHC), of OXT, OXTR, AVP, and AVPR1a in the placental tissue of pregnant women after an FEP in comparison to pregnant women without any health complication (HC-PW). Our results showed increased gene and protein expression of OXT, AVP, OXTR, and AVPR1A in the placental tissue of pregnant women who suffer an FEP. Therefore, our study suggests that an FEP during pregnancy may be associated with an abnormal paracrine/endocrine activity of the placenta, which can negatively affect the maternofetal wellbeing. Nevertheless, additional research is required to validate our findings and ascertain any potential implications of the observed alterations.

Copeptin levels in hospitalized infants and children with suspected vasopressin-dependent disorders: a case series

OBJECTIVES

There have been recent advances assessing copeptin levels in adults with suspected disorders of vasopressin release. Very limited data exits on copeptin levels in children and infants, especially in a critically-ill hospitalized population where hyper- and hypo-natremia are very common. Our objective is to describe the institutional experience assessing copeptin levels in hospitalized infants and children with hyper- or hypo-natremia.

METHODS

We performed a single-center retrospective case series of all infants, children, and adolescents who had an ultrasensitive plasma copeptin level obtained between 2019-2021.

RESULTS

A total of 29 critically ill patients (6 infants) were identified with 38 % of patients having copeptin levels after neurosurgical procedures for tumors or trauma. Approximately 13/17 children with hypernatremia had CDI to diagnose CDI, A copeptin level ≤ 4.9 pmol/L resulted in an 88 % sensitivity (95 % CI 47-99 %), and 66 % specificity (95 % CI 30-93 %). Amongst those with hyponatremia levels were more variable, 8/12 children had SIAD with copeptin levels ranging 4.7-72.6 pmol/L.

CONCLUSIONS

While difficult to conclude due to multiple limitations, this case series highlights that typical copeptin cutoffs used to diagnose DI in adults in an ambulatory setting may also translate to a critically-ill pediatric population. Large prospective studies are needed to confirm this observation. In addition, postoperative copeptin levels could potentially be utilized as an additional marker to predict permanent from transient DI, but much larger studies are needed. Further work is needed to establish normative copeptin levels in infants and patients with SIAD.

Acute regulation of erythropoietin via lower body negative pressure: Influence of sex and age

The regulation of erythropoiesis via hemodynamic stimuli such as reduced central blood volume (CBV) remains uncertain in women and elderly individuals. This study assessed the acute effects of lower body negative pressure (LBNP) on key endocrine biomarkers regulating erythropoiesis, that is, erythropoietin (EPO) and copeptin, in young and older women and men (n = 87). Transthoracic echocardiography and hemodynamics were assessed throughout incremental LBNP levels for 1 hour, or until presyncope, with established methods. Venous blood samples were collected at baseline and immediately after termination of the orthostatic tolerance (OT) test for subsequent hormone analyses. The average age of young women and men (33.1 ± 6.0 vs. 29.5 ± 6.9 yr) and older women and men (63.8 ± 8.0 vs. 65.3 ± 8.9 yr) as well as their physical activity levels were matched within each age and sex group. CBV, as determined by right atrial volume, was reduced in all individuals at the end of the OT test (p < 0.001). The average OT time ranged from 50.1 to 58.1 min in all individuals. LBNP increased circulating EPO in young women (p = 0.023) but not in young men or older individuals. Copeptin was increased in all individuals with LBNP but was exclusively associated with EPO in men (r = 0.39, p = 0.013). The present study indicates that the acute hemodynamic regulation of EPO production is both sex- and age-dependent.

Osmoadaptive GLP-1R signalling in hypothalamic neurones inhibits antidiuretic hormone synthesis and release

OBJECTIVES

The excessive release of the antidiuretic hormone vasopressin is implicated in many diseases including cardiovascular disease, diabetes, obesity, and metabolic syndrome. Once thought to be elevated as a consequence of diseases, data now supports a more causative role. We have previously identified CREB3L1 as a transcription factor that co-ordinates vasopressin synthesis and release in the hypothalamus. The objective here was to identify mechanisms orchestrated by CREB3L1 that co-ordinate vasopressin release.

METHODS

We mined Creb3l1 knockdown SON RNA-seq data to identify downstream target genes. We proceeded to investigate the expression of these genes and associated pathways in the supraoptic nucleus of the hypothalamus in response to physiological and pharmacological stimulation. We used viruses to selectively knockdown gene expression in the supraoptic nucleus and assessed physiological and metabolic parameters. We adopted a phosphoproteomics strategy to investigate mechanisms that facilitate hormone release by the pituitary gland.

RESULTS

We discovered glucagon like peptide 1 receptor (Glp1r) as a downstream target gene and found increased expression in stimulated vasopressin neurones. Selective knockdown of supraoptic nucleus Glp1rs resulted in decreased food intake and body weight. Treatment with GLP-1R agonist liraglutide decreased vasopressin synthesis and release. Quantitative phosphoproteomics of the pituitary neurointermediate lobe revealed that liraglutide initiates hyperphosphorylation of presynapse active zone proteins that control vasopressin exocytosis.

CONCLUSION

In summary, we show that GLP-1R signalling inhibits the vasopressin system. Our data advises that hydration status may influence the pharmacodynamics of GLP-1R agonists so should be considered in current therapeutic strategies.

The relationship between arginine vasopressin gene polymorphisms and plasma copeptin and hypertensive disorders of pregnancy: a nested case-control study

OBJECTIVES

This study aims to explore the relationship between polymorphism of the arginine vasopressin (AVP) gene and plasma copeptin concentration with the occurrence of hypertension in pregnancy.

METHODS

We conducted a matched nested case-control study in Chinese women. The genotypes of rs3729965, rs3761249, rs1410713, rs2740204, and rs2282018 loci of AVP gene and plasma copeptin at 16-20 gestational weeks were detected in 288 patients with gestational hypertension (GH), 82 with preeclampsia (PE), and 14 with chronic hypertension with superimposed preeclampsia (CH-PE) and their healthy matched controls.

RESULTS

For every natural logarithm unit increment in copeptin, the risks of GH and PE/CH-PE increased by 5.556 (adjusted odds ratio [aOR]: 6.556, 95% confidence interval [CI]: 2.734-15.717) and 3.312 times (aOR: 4.312, 95% CI: 1.168-15.914). Under the dominant model, the genotype CC + CT of rs2282018 and GG + GT of rs3761249 had higher risks of GH than genotype TT, with aORs of 1.757 (95% CI: 1.077-2.867) and 1.814 (95% CI: 1.111-2.963). Allele A of rs3729965 loci had a lower risk of PE/CH-PE than allele G (aOR: 0.441, 95% CI: 0.199-0.978). However, the frequencies of rs1410713 and rs2740204 genotypes were not significantly different between cases and controls. The model of copeptin combined with the AVP gene and traditional factors (TFs) had a higher ability than the TFs model in predicting GH and PE/CH-PE.

CONCLUSION

Our study confirms that higher plasma copeptin and AVP gene variants are associated with the occurrence of GH and PE/CH-PE. The detection of copeptin and AVP gene in the early second trimester improves the predictive ability of TFs for GH and PE/CH-PE.

The role of copeptin in kidney disease

Copeptin is a 39-amino acid glycopeptide that is secreted equimolecularly with arginine-vasopressin (AVP) from the prepro-hormone AVP in the posterior pituitary. While AVP is a very unstable molecule and is accompanied by significant technical troubles in its quantification, copeptin is a stable and easily quantifiable molecule. For this reason, circulating copeptin is currently used as a surrogate for AVP in different pathological conditions, including renal diseases. In recent years it has been shown that copeptin is associated with an increased risk of developing chronic kidney disease in the general population. In addition, copeptin has also been associated with multiple renal diseases with relevant clinical consequences and potential therapeutic implications. In the present review, we update and summarize the clinical significance of copeptin as a surrogate marker for AVP concentrations in different kidney diseases, as well as in renal replacement therapy (hemodialysis and peritoneal dialysis) and renal transplantation.

Measuring copeptin, a surrogate for vasopressin in patients with hypertension - Can it identify those who are volume Responsive?

BACKGROUND

Among hypertensive patients, plasma renin activity is lower and the response to diuretic monotherapy greater in volume responsive hypertensive patients. We hypothesized that hormones influencing extracellular volume such as vasopressin / antidiuretic hormone (ADH) might permit the development of a simple test to identify those with volume-related hypertension. Such a test might be of particular benefit to the Black population which is purported to have a higher incidence of volume-related and responsive hypertension. Thus, using copeptin, a surrogate marker for ADH, we studied if there were differences in this hormone between those with and without volume responsive hypertension.

METHODS

Serum copeptin was measured in biobanked blood samples from the Genetic Epidemiology of Responses to Antihypertensives (GERA) I study and analyzed with other variables from the study dataset.

RESULTS

There was no relationship between PRA and copeptin values nor could the response in blood pressure be predicted by the copeptin values. However, baseline copeptin levels were higher in Black than in White subjects (7.5 pmol/L vs 5.4 pmol/L, P < 0.001) while plasma sodium and calculated plasma osmolality were slightly lower in keeping with the concept that Black subjects have more volume-related hypertension. In addition, after hydrochlorothiazide (HCTZ), copeptin was significantly lower in Black (6.2 pmol/L, P = 0.004) but unchanged in White subjects (5.2 pmol/L, P = 0.901) and there were also changes in sodium.

CONCLUSION

The current study suggests differences in ADH physiology between hypertensive Black and White patients. However, the use of copeptin to identify volume responsive patients could not be confirmed.

Review novel insights into the diagnostic and prognostic function of copeptin in daily clinical practice

As is shown in previous reports, arginine vasopressin (AVP), as one of the most important hormones within circulation in human beings, is of great clinically significance given that it could maintain the body fluid balance and vascular tone. However, the laboratory measurements AVP in daily clinical practice are shown to be difficult and with low accuracy. Concerning on this notion, it is unpractical to use the serum levels of AVP in diagnosing multiple diseases. On the other hand, another key serum biomarker, copeptin, is confirmed as the C-terminal of the AVP precursor which could be released in equal amounts with AVP, resultantly making it as a sensitive marker of arginine vasopressin release. Notably, emerging recent evidence has demonstrated the critical function of copeptin as a clinical indicator, especially in the diagnosis and prognosis of several diseases in diverse organs, such as cardiovascular disease, kidney disease, and pulmonary disease. In addition, copeptin was recently verified to play an important role in diagnosing multiple acute diseases when combined it with other gold standard serum biomarkers, indicating that copeptin could be recognized as a vital disease marker. Herein, in the current review, the functions of copeptin as a new predictive diagnostic and prognostic biomarker of various diseases, according to the most recent studies, are well summarized. Furthermore, the importance of using copeptin as a serum biomarker in diverse medical departments and the impact of this on improving healthcare service is also summarized in the current review.

Copeptin plus troponin in the rapid rule out of acute myocardial infarction and prognostic value on post-myocardial infarction outcomes: a systematic review and diagnostic accuracy study

BACKGROUND

A critical and unmet therapeutic need is the prompt and reliable exclusion of acute myocardial infarction (AMI), which would allow for prompt discharge from the emergency department. High-sensitivity troponin (HS-TnT) combined with copeptin has been proposed to expedite the diagnostic exclusion of AMI in addition to its predictive usefulness in the intermediate and long-term outcomes of AMI. The European Society of Cardiology recommends the Global Registry of Acute Coronary Events (GRACE) as a prognostic score to manage acute coronary syndrome (ACS) without ST segment elevation. The purpose of this study was to compare the diagnostic accuracy of HS-TnT combined with copeptin in ruling out AMI compared to HS-TnT alone. By combining a low GRACE score (108) with negative HS-TnT (14 ng/L) and copeptin (14 pmol/L), non-ST and ACS were reliably ruled out, including non-ST segment elevation MI and unstable angina.

RESULTS

The present research included nine studies with a total of 13,232 participants. The negative predictive value (NPV) for copeptin and HS-TnT was found to be slightly higher in combination (62-99%) than for HS-TnT alone (60-99%). The sensitivity of copeptin ranged from 0% to 100%, with a pooled sensitivity of 0.79 (CI 95% 0.76, 0.82). The specificity of copeptin ranged from 13% to 100%, with a pooled specificity of 0.89 (CI 95% 0.85, 0.91), a pooled positive likelihood ratio (PLR) of 9.86 (CI 95% 4.42, 22.02), and a pooled negative likelihood ratio (NLR) of 0.08. (95% CI 0.01, 0.44).

CONCLUSIONS

The use of combined negative copeptin and highly sensitive troponin testing in low-to-intermediate risk patients with suspected acute coronary syndrome resulted in a quick discharge with a safe and rapid rule out of non-ST + ACS.

Combined Arginine and Insulin Stimulation Elicits a Robust and Consistent Copeptin Response in Short Children

INTRODUCTION

Copeptin, co-secreted with arginine vasopressin, is regulated by osmotic and volume stimuli but also responds to intravenous arginine and insulin-induced hypoglycemia. The serum copeptin response to the latter agents has been studied in adults but only to a limited extent in children. The objective of this study was to describe the copeptin response to combined arginine and insulin in children with normal posterior pituitary function.

METHODS

We conducted a prospective, single-arm assessment of serum copeptin concentrations in children (age 7-16 years, n = 38) undergoing growth hormone stimulation testing with an arginine-insulin tolerance test (AITT) for short stature or growth deceleration in a tertiary referral center. After overnight fasting, arginine (500 mg/kg) was administered between 0 and 30 min intravenously (IV) followed by insulin (0.1 units/kg IV) at 60 min. Copeptin serum concentrations were measured at baseline (0 min), at the post-arginine peak (60 min), and at the post-insulin peak (90 min; 30 min post-insulin), respectively. The main outcome was the peak copeptin concentration.

RESULTS

Mean ± SD copeptin concentrations increased from 9.9 ± 5.0 pmol/L at 0 min to 13.2 ± 5.8 pmol/L at 60 min (p < 0.0001 vs. 0 min) and 27.7 ± 14.2 pmol/L at 90 min (p < 0.0001 vs. 0 and 60 min). There was no significant correlation between copeptin concentrations and age, BMI, pubertal status, cortisol, growth hormone, or glucose concentrations.

DISCUSSION/CONCLUSION

Arginine and insulin appear to have an additive and consistent effect resulting in significant stimulation of copeptin secretion in children. The AITT may be a useful tool to evaluate for normal posterior pituitary function in this age-group, with potential implications for the evaluation of polyuria-polydipsia syndrome.

Predictive Value of Plasma Copeptin Level in Children with Acute Heart Failure

We investigated the ability of copeptin level to predict adverse outcome in pediatric heart failure (HF) and correlated copeptin level with various clinical and echocardiographic data. This cohort study was carried out on forty children with clinical picture of acute HF as the patient group and forty healthy children of matched age and sex as the control group. Echocardiographic examination and plasma copeptin level were performed for all included children at admission. Patients were followed up for 6 months for mortality or readmission. Plasma copeptin level was significantly higher in the patient group (16.2 ± 5) pmol/L compared to the control group (4.1 ± 2.3) pmol/L, P ˂0.001. Moreover, copeptin level was positively correlated with Ross classification, being the highest in patients with class IV (19.6 ± 3.9) pmol/L compared to those with class III (15.2 ± 4) pmol/L and class II (10.4 ± 1.5) pmol/L. Copeptin levels were significantly higher in patients with bad prognosis (21.2 ± 4.1) pmol/L compared to those with good prognosis (14.5 ± 4.1) pmol/L, P ˂0.001. Copeptin level had a significant positive correlation with age, heart rate, respiratory rate, and ROSS classification. On the contrary, copeptin level had a significant negative correlation with left ventricular fraction shortening and diastolic function. Copeptin at cut-off value of ≥ 19.5 pmol/L yielded a sensitivity of 75% and a specificity of 93% to predict adverse outcome in children with HF. Plasma copeptin level has a good prognostic value to predict adverse outcome in pediatric heart failure. Moreover, copeptin correlate well with the severity of pediatric HF.

Change in the pituitary stalk deviation angle after transsphenoidal surgery can predict the development of diabetes insipidus for pituitary adenomas

Purpose

We aimed to assess the factors influencing the development of diabetes insipidus after transsphenoidal surgery for pituitary adenomas.

Methods

A retrospective analysis was conducted on the clinical data of patients with pituitary adenomas who underwent transsphenoidal surgery. The predictors of postoperative diabetes insipidus were determined using statistical analysis.

Results

Of the 415 patients who underwent microscopic transsphenoidal surgery for pituitary adenomas, 196 experienced postoperative diabetes insipidus. The sinking depth of the diaphragma sellae and the difference between the preoperative and postoperative pituitary stalk deviation angles in the diabetes insipidus group were greater than those in the non-diabetes insipidus group. Logistic regression analysis showed that the risk of diabetes insipidus after transsphenoidal surgery was higher in patients with a larger difference in their pituitary stalk deviation angles (odds ratio = 2.407, 95% CI = 1.335-4.342; P = 0.004).

Conclusion

The difference in the pituitary stalk deviation angle could predict the onset of diabetes insipidus after transsphenoidal surgery for pituitary adenomas.

Norepinephrine innervation of the supraoptic nucleus contributes to increased copeptin and dilutional hyponatremia in male rats

Dilutional hyponatremia associated with liver cirrhosis is due to inappropriate release of arginine vasopressin (AVP). Elevated plasma AVP causes water retention resulting in a decrease in plasma osmolality. Cirrhosis, in this study caused by ligation of the common bile duct (BDL), leads to a decrease in central vascular blood volume and hypotension, stimuli for nonosmotic AVP release. The A1/A2 neurons stimulate the release of AVP from the supraoptic nucleus (SON) in response to nonosmotic stimuli. We hypothesize that the A1/A2 noradrenergic neurons support chronic release of AVP in cirrhosis leading to dilutional hyponatremia. Adult, male rats were anesthetized with 2-3% isoflurane (mixed with 95% O2/5% CO2) and injected in the SON with anti-dopamine β-hydroxylase (DBH) saporin (DSAP) or vehicle followed by either BDL or sham surgery. Plasma copeptin, osmolality, and hematocrit were measured. Brains were processed for ΔFosB, dopamine β-hydroxylase (DBH), and AVP immunohistochemistry. DSAP injection: 1) significantly reduced the number of DBH immunoreactive A1/A2 neurons (A1, P < 0.0001; A2, P = 0.0014), 2) significantly reduced the number of A1/A2 neurons immunoreactive to both DBH and ΔFosB positive neurons (A1, P = 0.0015; A2, P < 0.0001), 3) reduced the number of SON neurons immunoreactive to both AVP and ΔFosB (P < 0.0001), 4) prevented the increase in plasma copeptin observed in vehicle-injected BDL rats (P = 0.0011), and 5) normalized plasma osmolality and hematocrit (plasma osmolality, P = 0.0475; hematocrit, P = 0.0051) as compared with vehicle injection. Our data suggest that A1/A2 neurons contribute to increased plasma copeptin and hypoosmolality in male BDL rats.

Clinical significance of copeptin as an early predictor of renal graft dysfunction in renal transplant recipients

Background: Copeptin is the carboxyl-terminal part of the vasopressin precursor protein, and its concentration is an independent predictor of the onset of chronic kidney disease and a rapid decline in the glomerular filtration rate. The glomerular filtration rate is regarded as the best indicator of kidney transplant function and is a predictor of graft and patient survival. We investigated the clinical significance of copeptin as an early predictor of renal graft dysfunction in renal transplant recipients.Methods: We measured serum creatinine, cystatin C, and copeptin concentrations in renal transplant recipients on the day of their operation, as well as on postoperative days 3, 7, 30, and 365. Acute rejection was defined as a sudden decrease in renal function accompanied by histological changes.Results: Eight renal transplant recipients were enrolled in the study from July 2018 to December 2019. Four patients experienced histologically confirmed transplant rejection. All four cases involved acute T-cell rejection. No significant correlation was found between the copeptin level and the presence or absence of rejection at any time point. In subgroup analyses, changes in creatinine, the estimated glomerular filtration rate, cystatin, and copeptin did not show statistical significance.Conclusions: We anticipated that copeptin would be useful to identify individuals at high risk of transplant rejection; however, our study failed to show an association. Further research will be needed to overcome the limitations of this study.

Signs of Anxiety and Salivary Copeptin Levels in Dogs Diagnosed with Separation-Related Problems in a Short Separation Test

The need for faster diagnosis and more accurate treatment decisions in separation-related problems (SRPs) in dogs is urgent, and a more precise behavioral phenotyping and the development of biomarkers may be of great value. Vasopressin could be a potential non-invasive biomarker of anxiety in dogs with SRPs, but reliable measurement of its concentration is challenging. Here, we compared the behavior and salivary concentrations of copeptin, an arginine vasopressin surrogate, in dogs with SRPs (Case group, n = 13) and with no problems (Control group, n = 15) as they were introduced to a novel environment and subjected to a short episode of separation and reunion with the owner. Dogs in the Case group had greater odds of showing locomotory or oral behaviors during the pre- and post-separation than Controls, while the odds were significantly lower during separation. They also had greater odds of being persistent in seeking attention and proximity from the stranger during reunion. Overall, dogs with SRPs were more likely to express an anxiety-like state during the entire test than Controls, with separation from the owner, and even its anticipation, possibly accounting for this group difference. Although salivary copeptin concentrations did not differ between the two groups, a different trend was detected in Cases and Controls that is worth exploring in further validation studies involving a larger sample.

Conivaptan and Boric Acid Treatments in Acute Kidney Injury: Is This Combination Effective and Safe?

Acute kidney injury is still a worldwide clinic problem that affects kidney function and associated with high mortality risk. Unfortunately, approximately 1.7 million people are thought to die from acute kidney injury each year. Boron element is defined as an "essential trace element" for plants and thought to have a widespread role in living organisms. Boric acid, which is one of the important forms of boron, has been extensively discussed for both medicinal and nonmedicinal purposes. However, there is a lack of data in the literature to examine the relationship between boric acid and antidiuretic hormone (ADH) antagonism in kidney injury. Thus, we aimed to investigate the effects of conivaptan as an ADH antagonist and boric acid as an antioxidant agent on the post-ischemic renal injury process. In this study, the unilateral ischemia-reperfusion (I/R) injury rat model with contralateral nephrectomy was performed and blood/kidney tissue samples were taken at 6th hours of reperfusion. The effects of 10 mg/mL/kg conivaptan and 50 mg/kg boric acid were examined with the help of some biochemical and histological analyses. We observed that conivaptan generally alleviated the destructive effects of I/R and has therapeutic effects. Also of note is that conivaptan and boric acid combination tended to show negative effects on kidney function, considering the highest BUN (78.46 ± 3.88 mg/dL) and creatinine levels (1.561 ± 0.1018 mg/dL), suggesting possibly drug-drug interaction. Although it has reported that conivaptan can interact with other active substances, no experimental/clinical data on the possible interaction with boric acid have reported so far.

Renal Deletion of LRRC8/VRAC Channels Induces Proximal Tubulopathy

BACKGROUND

Volume-regulated anion channels (VRACs) are heterohexamers of LRRC8A with LRRC8B, -C, -D, or -E in various combinations. Depending on the subunit composition, these swelling-activated channels conduct chloride, amino acids, organic osmolytes, and drugs. Despite VRACs' role in cell volume regulation, and large osmolarity changes in the kidney, neither the localization nor the function of VRACs in the kidney is known.

METHODS

Mice expressing epitope-tagged LRRC8 subunits were used to determine the renal localization of all VRAC subunits. Mice carrying constitutive deletions of Lrrc8b-e, or with inducible or cell-specific ablation of Lrrc8a, were analyzed to assess renal functions of VRACs. Analysis included histology, urine and serum parameters in different diuresis states, and metabolomics.

RESULTS

The kidney expresses all five VRAC subunits with strikingly distinct localization. Whereas LRRC8C is exclusively found in vascular endothelium, all other subunits are found in the nephron. LRRC8E is specific for intercalated cells, whereas LRRC8A, LRRC8B, and LRRC8D are prominent in basolateral membranes of proximal tubules. Conditional deletion of LRRC8A in proximal but not distal tubules and constitutive deletion of LRRC8D cause proximal tubular injury, increased diuresis, and mild Fanconi-like symptoms.

CONCLUSIONS

VRAC/LRRC8 channels are crucial for the function and integrity of proximal tubules, but not for more distal nephron segments despite their larger need for volume regulation. LRRC8A/D channels may be required for the basolateral exit of many organic compounds, including cellular metabolites, in proximal tubules. Proximal tubular injury likely results from combined accumulation of several transported molecules in the absence of VRAC channels.

Seasonal variation of vasopressin and its relevance for the winter peak of cardiometabolic disease: A pooled analysis of five cohorts

BACKGROUND

Vasopressin concentration is typically higher at night, during stress, and in males, but readily lowered by water intake. Vasopressin is also a causal candidate for cardiometabolic disease, which shows seasonal variation.

OBJECTIVE

To study whether vasopressin concentration varies by season in a temperate climate.

METHODS

The vasopressin surrogate marker copeptin was analyzed in fasting plasma samples from five population-based cohorts in Malmö, Sweden (n = 25,907, 50.4% women, age 18-86 years). We investigated seasonal variation of copeptin concentration and adjusted for confounders in sinusoidal models.

RESULTS

The predicted median copeptin level was 5.81 pmol/L (7.18 pmol/L for men and 4.44 pmol/L for women). Copeptin exhibited a distinct seasonal pattern with a peak in winter (mid-February to mid-March) and nadir in late summer (mid-August to mid-September). The adjusted absolute seasonal variation in median copeptin was 0.62 pmol/L (95% confidence interval [CI] 0.50; 0.74, 0.98 pmol/L [95% CI 0.73; 1.23] for men and 0.46 pmol/L [95% CI 0.33; 0.59] for women). The adjusted relative seasonal variation in mean log copeptin z-score was 0.20 (95% CI 0.17; 0.24, 0.18 [95% CI 0.14; 0.23] in men and 0.24 [95% CI 0.19; 0.29] in women). The observed seasonal variation of copeptin corresponded to a risk increase of 4% for incident diabetes mellitus and 2% for incident coronary artery disease.

CONCLUSION

The seasonal variation of the vasopressin marker copeptin corresponds to increased disease risk and mirrors the known variation in cardiometabolic status across the year. Moderately increased water intake might mitigate the winter peak of cardiometabolic disease.

An Overview of Circulating Pulmonary Arterial Hypertension Biomarkers

Pulmonary arterial hypertension (PAH), also known as Group 1 Pulmonary Hypertension (PH), is a PH subset characterized by pulmonary vascular remodeling and pulmonary arterial obstruction. PAH has an estimated incidence of 15-50 people per million in the United States and Europe, and is associated with high mortality and morbidity, with patients' survival time after diagnosis being only 2.8 years. According to current guidelines, right heart catheterization is the gold standard for diagnostic and prognostic evaluation of PAH patients. However, this technique is highly invasive, so it is not used in routine clinical practice or patient follow-up. Thereby, it is essential to find new non-invasive strategies for evaluating disease progression. Biomarkers can be an effective solution for determining PAH patient prognosis and response to therapy, and aiding in diagnostic efforts, so long as their detection is non-invasive, easy, and objective. This review aims to clarify and describe some of the potential new candidates as circulating biomarkers of PAH.

Aptamers Targeting Cardiac Biomarkers as an Analytical Tool for the Diagnostics of Cardiovascular Diseases: A Review

The detection of cardiac biomarkers is used for diagnostics, prognostics, and the risk assessment of cardiovascular diseases. The analysis of cardiac biomarkers is routinely performed with high-sensitivity immunological assays. Aptamers offer an attractive alternative to antibodies for analytical applications but, to date, are not widely practically implemented in diagnostics and medicinal research. This review summarizes the information on the most common cardiac biomarkers and the current state of aptamer research regarding these biomarkers. Aptamers as an analytical tool are well established for troponin I, troponin T, myoglobin, and C-reactive protein. For the rest of the considered cardiac biomarkers, the isolation of novel aptamers or more detailed characterization of the known aptamers are required. More attention should be addressed to the development of dual-aptamer sandwich detection assays and to the studies of aptamer sensing in alternative biological fluids. The universalization of aptamer-based biomarker detection platforms and the integration of aptamer-based sensing to clinical studies are demanded for the practical implementation of aptamers to routine diagnostics. Nevertheless, the wide usage of aptamers for the diagnostics of cardiovascular diseases is promising for the future, with respect to both point-of-care and laboratory testing.

Circulating Biomarkers in Long-Term Stroke Prognosis: A Scoping Review Focusing on the South African Setting

Cerebrovascular disease, including both ischaemic and haemorrhagic strokes, remains one of the highest causes of global morbidity and mortality. Developing nations, such as South Africa (SA), are affected disproportionately. Early identification of stroke patients at risk of poor clinical prognosis may result in improved outcomes. In addition to conventional neuroimaging, the role of predictive biomarkers has been shown to be important. Little data exist on their applicability within SA. This scoping review aimed to evaluate the currently available data pertaining to blood biomarkers that aid in the long-term prognostication of patients following stroke and its potential application in the South African setting. This scoping review followed a 6-stage process to identify and critically review currently available literature pertaining to prognostic biomarkers in stroke. An initial 1191 articles were identified and, following rigorous review, 41 articles were included for the purposes of the scoping review. A number of potential biomarkers were identified and grouped according to the function or origin of the marker. Although most biomarkers showed great prognostic potential, the cost and availability will likely limit their application within SA. The burden of stroke is increasing worldwide and appears to be affecting developing countries disproportionately. Access to neuroradiological services is not readily available in all settings and the addition of biomarkers to assist in the long-term prognostication of patients following a stroke can be of great clinical value. The cost and availability of many of the reviewed biomarkers will likely hinder their use in the South African setting.

The correlation of cardiac biomarkers and myocardial iron overload based on T2* MRI in major beta-thalassemia

Cardiac hemosiderosis is the primary factor to derive the pathogenesis of cardiac dysfunction in patients with transfusion dependent thalassemia. Biomarkers assessment along with T2 * MRI study could be employed to evaluate the severity of iron deposition-related damage and determination of the diagnostic and prognostic value of these inflammatory factors. The study was conducted on 62 patients (12-44 years old) with major thalassemia. The patients were under regular blood transfusion and they had no signs of cardiac defects, and chronic diseases. The serum levels of inflammatory factors (NT-proBNP, CRP, Copeptin HS) were determined before routine transfusion. Cardiac iron overload was assessed by T2* MRI (within the last three months), and T2* lower than 20 ms was considered as cardiac siderosis. The obtained results were analyzed using statistical methods. 92% of patients showed an increased level of hs-CRP (> 2 µg/dL). All cases showed increased levels of NT-proBNP (> 150 pg/mL). Only 29% of subjects showed high level of Copeptin, 25.8% of patients demonstrated cardiac siderosis based on the T2* MRI (< 20 ms) results. The serum levels of inflammatory factors were not significantly correlated with cardiac siderosis. Given the obtained results, it could be deduced that the serum levels of inflammatory factors could not be exploited for early detection of cardiac siderosis in major beta-thalassemia patients.

Emerging Biomarkers of Multiple Sclerosis in the Blood and the CSF: A Focus on Neurofilaments and Therapeutic Considerations

INTRODUCTION

Multiple Sclerosis (MS) is the most common immune-mediated chronic neurodegenerative disease of the central nervous system (CNS) affecting young people. This is due to the permanent disability, cognitive impairment, and the enormous detrimental impact MS can exert on a patient's health-related quality of life. It is of great importance to recognise it in time and commence adequate treatment at an early stage. The currently used disease-modifying therapies (DMT) aim to reduce disease activity and thus halt disability development, which in current clinical practice are monitored by clinical and imaging parameters but not by biomarkers found in blood and/or the cerebrospinal fluid (CSF). Both clinical and radiological measures routinely used to monitor disease activity lack information on the fundamental pathophysiological features and mechanisms of MS. Furthermore, they lag behind the disease process itself. By the time a clinical relapse becomes evident or a new lesion appears on the MRI scan, potentially irreversible damage has already occurred in the CNS. In recent years, several biomarkers that previously have been linked to other neurological and immunological diseases have received increased attention in MS. Additionally, other novel, potential biomarkers with prognostic and diagnostic properties have been detected in the CSF and blood of MS patients.

AREAS COVERED

In this review, we summarise the most up-to-date knowledge and research conducted on the already known and most promising new biomarker candidates found in the CSF and blood of MS patients.

DISCUSSION

the current diagnostic criteria of MS relies on three pillars: MRI imaging, clinical events, and the presence of oligoclonal bands in the CSF (which was reinstated into the diagnostic criteria by the most recent revision). Even though the most recent McDonald criteria made the diagnosis of MS faster than the prior iteration, it is still not an infallible diagnostic toolset, especially at the very early stage of the clinically isolated syndrome. Together with the gold standard MRI and clinical measures, ancillary blood and CSF biomarkers may not just improve diagnostic accuracy and speed but very well may become agents to monitor therapeutic efficacy and make even more personalised treatment in MS a reality in the near future. The major disadvantage of these biomarkers in the past has been the need to obtain CSF to measure them. However, the recent advances in extremely sensitive immunoassays made their measurement possible from peripheral blood even when present only in minuscule concentrations. This should mark the beginning of a new biomarker research and utilisation era in MS.

Exercise-Induced Hyponatremia: An Assessment of the International Hydration Recommendations Followed During the Gran Trail De Peñalara and Vitoria-Gasteiz Ironman Competitions

Introduction

Hyponatremia often occurs during the practice of endurance sports. We evaluated the impact on hyponatremia of the hydration recommendations of the Third International Exercise-Associated Hyponatremia Consensus Development Conference 2015 (3IE-AHCD) during the 2017 Gran Trail de Peñalara marathon (GTP) and the Vitoria Gasteiz Ironman triathlon (VGI).

Methods

Prospective study of GTP and VGI athletes participating in four information sessions in the months prior to the events, to explain that hydration should only be according to their level of thirst, per the recommendations of the 3IE-AHCD. Consenting event finishers were included in final analysis. Pre- and post-race anthropometric and biochemical parameters were compared.

Results

Thirty-six GTP (33 male) and 94 VGI (88 male) finishers were evaluated. GTP race median fluid intake was 800 ml/h, with 900 ml/h in the VGI race. 83.3% GTPfin and 77.6% VGIfin remained eunatremic (blood sodium 135–145 mmol/L). Only 1/36 GTP and 1/94 VGI participant finished in hyponatremia, both with a sodium level of 134 mmol/L. Fourteen percent of GTP, and 21.2% of VGI participants finished in hypernatremia, with no increase in race completion times. No participating athlete required medical attention, except for musculoskeletal complaints. Pro-BNP and Copeptin levels rose significantly. Changes in copeptin levels did not correlate with changes in plasma osmolality, nor total body water content in impedance analysis.

Conclusions

Recommending that athletes' fluid intake in endurance events be a function of their thirst almost entirely prevented development of hyponatremia, without induction of clinically significant hypernatremia, or a negative repercussion on race completion times.

Biomarkers for Transient Ischemic Attack: A Brief Perspective of Current Reports and Future Horizons

Cerebrovascular disease is the leading cause of long-term disability in the world and the third-leading cause of death in the United States. The early diagnosis of transient ischemic attack (TIA) is of great importance for reducing the mortality and morbidity of cerebrovascular diseases. Patients with TIA have a high risk of early subsequent ischemic stroke and the development of permanent nervous system lesions. The diagnosis of TIA remains a clinical diagnosis that highly relies on the patient's medical history assessment. There is a growing list of biomarkers associated with different components of the ischemic cascade in the brain. In this review, we take a closer look at the biomarkers of TIA and their validity with a focus on the more clinically important ones using recent evidence of their reliability for practical usage.

Endocrine system dysfunction and chronic heart failure: a clinical perspective

Chronic heart failure (CHF) leads to an excess of urgent ambulatory visits, recurrent hospital admissions, morbidity, and mortality regardless of medical and non-medical management of the disease. This excess of risk may be attributable, at least in part, to comorbid conditions influencing the development and progression of CHF. In this perspective, the authors examined and described the most common endocrine disorders observed in patients with CHF, particularly in individuals with reduced ejection fraction, aiming to qualify the risks, quantify the epidemiological burden and discuss about the potential role of endocrine treatment. Thyroid dysfunction is commonly observed in patients with CHF, and sometimes it could be the consequence of certain medications (e.g., amiodarone). Male and female hypogonadism may also coexist in this clinical context, contributing to deteriorating the prognosis of these patients. Furthermore, growth hormone deficiency may affect the development of adult myocardium and predispose to CHF. Limited recommendation suggests to screen endocrine disorders in CHF patients, but it could be interesting to evaluate possible endocrine dysfunction in this setting, especially when a high suspicion coexists. Data referring to long-term safety and effectiveness of endocrine treatments in patients with CHF are limited, and their impact on several "hard" endpoints (such as hospital admission, all-cause, and cardiovascular mortality) are still poorly understood.

Hypohydration but not Menstrual Phase Influences Pain Perception in Healthy Women

Chronic pain is a pervasive health problem and is associated with tremendous socioeconomic costs. However, current pain treatments are often ineffective due, in part, to the multi-factorial nature of pain. Mild hypohydration was shown to increase experimental pain sensitivity in men, but whether this also occurs in women has not been examined. Fluctuations in ovarian hormones (i.e., 17ß-oestradiol and progesterone) throughout the menstrual cycle may influence a woman's pain sensitivity, as well as hydration levels, suggesting possible interactions between hypohydration and menstrual phase on pain. We investigated the effects of mild hypohydration (HYPO, 24 hr of fluid restriction) on ischaemic pain sensitivity in 14 eumenorrheic women during the early follicular (EF) and mid-luteal (ML) phases of their menstrual cycle. We also examined whether acute water ingestion could reverse the negative effects of hypohydration. Elevated serum osmolality, plasma copeptin, and urine specific gravity indicated mild hypohydration. Compared to euhydration, HYPO reduced pain tolerance (by 34 ± 46 s; P = 0.02, ηp2 = 0.37) and increased ratings of pain intensity (by 0.7 ± 0.7 cm; P = 0.004; ηp2 = 0.55) and unpleasantness (by 0.7 ± 0.9 cm; P = 0.02; ηp2 = 0.40); these results were not influenced by menstrual phase. Water ingestion reduced thirst perception (Visual Analogue Scale, by 2.3 ± 0.9 cm; P < 0.001, ηp2 = 0.88) but did not reduce pain sensitivity. Therefore, hypohydration increases pain sensitivity in women with no influence of menstrual phase.

Circulating Blood-Based Biomarkers in Pulmonary Hypertension

Pulmonary hypertension (PH) is a serious hemodynamic condition, characterized by increased pulmonary vascular resistance (PVR), leading to right heart failure (HF) and death when not properly treated. The prognosis of PH depends on etiology, hemodynamic and biochemical parameters, as well as on response to specific treatment. Biomarkers appear to be useful noninvasive tools, providing information about the disease severity, treatment response, and prognosis. However, given the complexity of PH, it is impossible for a single biomarker to be adequate for the broad assessment of patients with different types of PH. The search for novel emerging biomarkers is still ongoing, resulting in a few potential biomarkers mirroring numerous pathophysiological courses. In this review, markers related to HF, myocardial remodeling, inflammation, hypoxia and tissue damage, and endothelial and pulmonary smooth muscle cell dysfunction are discussed in terms of diagnosis and prognosis. Extracellular vesicles and other markers with complex backgrounds are also reviewed. In conclusion, although many promising biomarkers have been identified and studied in recent years, there are still insufficient data on the application of multimarker strategies for monitoring and risk stratification in PH patients.

Copeptin assays in children for the differential diagnosis of polyuria-polydipsia syndrome and reference levels in hospitalized children

OBJECTIVES

Polyuria-polydipsia syndrome (PPS) is a common presentation in children but the differential diagnosis rests on burdensome water deprivation tests. The aims of this study were to determine a copeptin threshold to distinguish patients with central diabetes insipidus from those with primary polydipsia and to estimate the normal range of copeptin concentrations in children.

DESIGN

Single-centre retrospective descriptive study.

PATIENTS

Two hundred and seventy-eight children aged 2 months to 18 years who consulted for PPS (N = 40) or other reasons (control group, N = 238) at La Timone University Hospital in Marseille, France, between April 2015 and September 2019 and had a copeptin assay.

MEASUREMENTS

Ultrasensitive copeptin assays on blood samples.

RESULTS

Among the children with PPS, the mean copeptin concentrations were 1.72, 55.2 and 15.7 pmol/l in those with central diabetes insipidus (N = 21), nephrogenic diabetes insipidus (N = 3), and primary polydipsia (N = 16), respectively. Copeptin levels lower than 3.53 pmol/l were diagnostic of central diabetes insipidus with 100% sensitivity and 87.4% specificity (p < .001). The 5th-95th copeptin percentile range in the control group was 2.53-21.03 pmol/L. Copeptin levels were significantly higher in boys than in girls but there was no association with age, pubertal stage, body mass index, or the reason for consulting.

CONCLUSIONS

Our results indicate copeptin assays may be valuable in the differential diagnosis of PPS in children. Larger prospective studies are required to establish their accuracy in everyday clinical practice.

Arginine-vasopressin mediates counter-regulatory glucagon release and is diminished in type 1 diabetes

Insulin-induced hypoglycemia is a major treatment barrier in type-1 diabetes (T1D). Accordingly, it is important that we understand the mechanisms regulating the circulating levels of glucagon. Varying glucose over the range of concentrations that occur physiologically between the fed and fuel-deprived states (8 to 4 mM) has no significant effect on glucagon secretion in the perfused mouse pancreas or in isolated mouse islets (in vitro), and yet associates with dramatic increases in plasma glucagon. The identity of the systemic factor(s) that elevates circulating glucagon remains unknown. Here, we show that arginine-vasopressin (AVP), secreted from the posterior pituitary, stimulates glucagon secretion. Alpha-cells express high levels of the vasopressin 1b receptor (V1bR) gene (Avpr1b). Activation of AVP neurons in vivo increased circulating copeptin (the C-terminal segment of the AVP precursor peptide) and increased blood glucose; effects blocked by pharmacological antagonism of either the glucagon receptor or V1bR. AVP also mediates the stimulatory effects of hypoglycemia produced by exogenous insulin and 2-deoxy-D-glucose on glucagon secretion. We show that the A1/C1 neurons of the medulla oblongata drive AVP neuron activation in response to insulin-induced hypoglycemia. AVP injection increased cytoplasmic Ca2+ in alpha-cells (implanted into the anterior chamber of the eye) and glucagon release. Hypoglycemia also increases circulating levels of AVP/copeptin in humans and this hormone stimulates glucagon secretion from human islets. In patients with T1D, hypoglycemia failed to increase both copeptin and glucagon. These findings suggest that AVP is a physiological systemic regulator of glucagon secretion and that this mechanism becomes impaired in T1D.

Diagnostic biomarkers of dilated cardiomyopathy

BACKGROUND

Dilated cardiomyopathy (DCM) is a condition involving dilation of cardiac chambers, which results in contraction impairment. Besides invasive and non-invasive diagnostic procedures, cardiac biomarkers are of great importance in both diagnosis and prognosis of the disease. These biomarkers are categorized into three groups based on their site; cardiomyocyte biomarkers, microenvironmental biomarkers and macroenvironmental biomarkers.

AIMS

In this review, an overview of characteristics, epidemiology, etiology and clinical manifestations of DCM is provided. In addition, the most important biomarkers, of all three categories, and their diagnostic and prognostic values are discussed.

CONCLUSION

Considering the association of DCM with conditions such as infections and autoimmunity, which are prevalent among the population, introducing efficient diagnostic tools is of high value for the early detection of DCM to prevent its severe complications. The three discussed classes of biomarkers are potential candidates for the detection of DCM. However, further studies are necessary in this regard.

Copeptin and Stress

Vasopressin (AVP) and copeptin are released in equimolar amounts from the same precursor. Due to its molecular stability and countless advantages as compared with AVP, copeptin perfectly mirrors AVP presence and has progressively emerged as a reliable marker of vasopressinergic activation in response to osmotic and hemodynamic stimuli in clinical practice. Moreover, evidence highlighting the prognostic potential of copeptin in several acute diseases, where the activation of the AVP system is primarily linked to stress, as well as in psychologically stressful conditions, has progressively emerged. Furthermore, organic stressors induce a rise in copeptin levels which, although non-specific, is unrelated to plasma osmolality but proportional to their magnitude: suggesting disease severity, copeptin proved to be a reliable prognostic biomarker in acute conditions, such as sepsis, early post-surgical period, cardiovascular, cerebrovascular or pulmonary diseases, and even in critical settings. Evidence on this topic will be briefly discussed in this article.

Prognostic performance of copeptin among patients with acute decompensated heart failure

BACKGROUND

In heart failure (HF), various biomarkers have been established for prognosis. However, little is known about the relevance of copeptin measurements to HF. This study aimed to explore the prognostic value of copeptin for predicting cardiovascular (CV) death or HF-related re-hospitalisation in patients with acute decompensated HF.

MATERIALS AND METHODS

We prospectively enrolled 155 consecutive patients with acute signs and symptoms of HF. Plasma copeptin and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were measured at admission. Patients were monitored for 90 days regarding the composite endpoint of CV death or acute HF-related re-hospitalisation.

RESULTS

Of the 155 patients enrolled, 40 reached the endpoint, and 115 were in a stable condition during follow-up. Patients who reached an adverse endpoint showed higher NT-proBNP and copeptin levels compared to patients in stable condition. Receiver operating characteristic curve analysis revealed that the area under curve of copeptin 0.844 (95% CI, 0.753-0.935) was superior to that of NT-proBNP 0.809 (95% CI, 0.729-0.890) for the prediction of adverse events within 90 days. Meanwhile, compared to the group with lower copeptin levels (<34 pmol/L), patients with higher copeptin levels (≥34 pmol/L) were at a 10.672-times higher risk of CV death or acute HF-related re-hospitalisation. Multivariate Cox proportional hazards regression analysis revealed that increased copeptin level was a significantly independent predictor of adverse events (risk ratio, 1.051; 95% CI, 1.020-1.083; p < 0.001).

CONCLUSION

Copeptin was found to be a strong, novel marker for predicting CV death or HF-related re-hospitalisation in patients with acute decompensated HF.

Plasma copeptin levels in children with pulmonary arterial hypertension associated with congenital heart disease

The study aimed to evaluate the plasma copeptin levels in children with pulmonary arterial hypertension associated with congenital heart disease (PAH-CHD), to assess the predictive value of plasma copeptin level for adverse outcomes, and to correlate its levels with various data in these patients. We included 25 children with PAH-CHD as group I and 25 children with CHD and no PAH as group II. Twenty-five healthy children of matched age and sex served as the control group. Patients were evaluated by echocardiography and right heart catheterization. The plasma level of copeptin was also measured. All patients were followed up for death or readmission for 1 year. Plasma copeptin levels were significantly higher in group I compared to group II and the control group and were correlated with increasing severity of PAH. The best cutoff of plasma copeptin level to predict poor prognosis in group I was ≥24.2 ng/ml with a sensitivity of 90% and a specificity of 80%. There was a statistically significant positive correlation between plasma copeptin levels and mean pulmonary pressure, pulmonary vascular resistance, and pulmonary blood flow, while there was a statistically significant negative correlation between plasma copeptin levels and right ventricular diastolic function.Conclusion: Plasma copeptin levels are elevated in children with PAH-CHD and found to be a good predictive marker for the severity of PAH and poor prognosis in these children. What is Known: •PH is a life-threatening condition that can lead to right ventricular failure and death. •We need a non-invasive easy biomarker that can identify PH children with unfavorable prognosis who needed further intervention. What is New: •It is the first study that assessed the prognostic value of plasma copeptin levels in children with PAH-CHD. •We found that copeptin is an accurate dependable biomarker for predicting poor outcomes in children with PAH-CHD who needed extensive further intervention.

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.

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.