Vasopressin and copeptin levels in children with sepsis and septic shock

Copeptin as a diagnostic and prognostic biomarker in pediatric diseases

Arginine vasopressin (AVP) plays a main role in maintaining the homeostasis of fluid balance and vascular tone and in regulating the endocrine stress response in response to osmotic, hemodynamic and stress stimuli. However, the difficulty in measuring AVP limits its clinical application. Copeptin, the C-terminal part of the AVP precursor, is released in an equimolar concentration mode with AVP from the pituitary but is more stable and simple to measure. Therefore, copeptin has emerged as a promising surrogate marker of AVP with excellent potential for the diagnosis, differentiation and prognosis of various diseases in recent decades. However, its application requires further validation, especially in the pediatric population. This review focuses on the clinical value of copeptin in different pediatric diseases and the prospects for its application as a potential biomarker.

Association of copeptin levels with patient prognosis and survival in sepsis syndromes: a meta-analysis

BACKGROUND

Sepsis syndromes are a major burden in the ICU with very high mortality. Vasopressin and copeptin are released in response to hypovolemia and have shown potential significance in diagnosing sepsis.

OBJECTIVE

To investigate the levels of copeptin in patients with sepsis syndromes and evaluate its relation with patient prognosis and mortality.

METHODS

Four databases were searched for literature published from inception to the 8th of November 2022. Original research articles where copeptin was measured in sepsis patients and compared with controls were included. Data extraction and synthesis: study characteristics, levels of copeptin in the participants, and copeptin assay description were extracted. Levels of copeptin in patients were pooled and compared with controls in terms of the standard mean difference (SMD) generated using a random-effects model.

RESULTS

Fifteen studies met the selection criteria. Copeptin levels were significantly higher in patients with sepsis, severe sepsis, and septic shock as compared to controls [(SMD: 1.49, 95% CI: 0.81-2.16, P<0.0001), (SMD: 1.94, 95% CI: 0.34-3.54, P=0.02), and (SMD: 2.17, 95% CI: 0.68-3.66, P=0.004), respectively]. The highest copeptin levels were noted in septic shock patients. The admission copeptin levels were significantly lower in survivors as compared to nonsurvivors (SMD: -1.73; 95% CI: -2.41 to -1.06, P<0.001).

CONCLUSION AND RELEVANCE

Copeptin was significantly elevated in sepsis, severe sepsis, and septic shock. Survivors had a significantly lower copeptin during admission. Copeptin offered an excellent predictability to predict 1-month mortality. Measuring the copeptin in sepsis patients can aid treating physicians to foresee patients' prognosis.

Paediatric perspectives in the diagnosis of polyuria-polydipsia syndrome

The elucidation of the underlying cause of polyuria-polydipsia syndrome (PPS) is a challenging-especially in the differentiation of partial defects of arginine vasopressin (AVP) secretion or action from primary polydipsia. The water deprivation test has been utilized for many decades, and its application in the paediatric population has been applied using parameters predominantly established in adult cohorts. In more recent times, the development of automated commercial assays for copeptin, a surrogate marker for AVP, has represented a significant advancement in the diagnostic approach to PPS. Measurement of copeptin concentrations has major advantages and has essentially superseded measurement of AVP in diagnostic protocols for PPS. Additionally, stimulated-copeptin protocols utilizing hypertonic saline infusion, arginine, and glucagon have been investigated, and are promising. However, further studies are required in the population-incorporating the differences in physiological regulation of water homeostasis, and safety requirements-before there is widespread adoption into clinical practice.

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).

Pediatric sepsis diagnostic and prognostic biomarkers: pancreatic stone protein, copeptin, and apolipoprotein A-V

BACKGROUND

We assessed serum concentrations of pancreatic stone protein (PSP), copeptin, and apolipoprotein A-V (APOA5) biomarkers for the diagnosis and prognosis of pediatric sepsis, a condition associated with high mortality.

METHODS

This prospective study included 180 children admitted to the Pediatric Intensive Care Unit and 100 healthy controls at Menoufia University Hospital. Pediatric Risk of Mortality (PRISM), Pediatric Index of Mortality-2 (PIM2), and Pediatric Sequential Organ Failure Assessment (pSOFA) scores were calculated. Serum PSP, copeptin and APOA5 were measured once within 24 h of admission.

RESULTS

PSP, copeptin, and APOA5 were significantly higher in the patients than in the controls (p < 0.001). PSP and copeptin were increased among children who required mechanical ventilation (MV), had multiple organ dysfunctions, and were non-survivors, but APOA5 was decreased in those children. Logistic regression analyses showed that high pSOFA, high PSP and copeptin, low APOA5, and use of MV were associated with mortality. The receiver operating characteristic revealed that the area under the curve (AUC) for APOA5, copeptin, and PSP (0.965, 0.960, and 0.868, respectively) demonstrated high sensitivity (96%, 94%, and 80%) for sepsis diagnosis. The AUC values for PSP, copeptin, and APOA5 were 0.709, 0.705, and 0.571, respectively, with sensitivities of 74%, 58%, and 58% for mortality prediction.

CONCLUSIONS

PSP, copeptin, and APOA5 are promising diagnostic biomarkers for pediatric sepsis but inadequate predictors of mortality.

IMPACT

Apolipoprotein A-V (APOA5), copeptin, and pancreatic stone protein (PSP) are acute-phase proteins with diagnostic value in evaluating critically ill pediatric patients with sepsis and detecting sepsis severity. PSP and copeptin had the power to discriminate non-survivors from survivors. APOA5 was less powerful than the other biomarkers in discriminating between survivors and non-survivors.

Copeptin Release in Arterial Hypotension and Its Association with Severity of Disease in Critically Ill Children

Low copeptin levels may indicate inadequate arginine-vasopressin release promoting arterial hypotension, whereas high copeptin concentrations may reflect disease severity. This single-center prospective non-randomized clinical trial analyzed the course of blood copeptin in critically ill normo- and hypotensive children and its association with disease severity. In 164 patients (median age 0.5 years (interquartile range 0.1, 2.9)), the mean copeptin concentration at baseline was 43.5 pmol/L. Though not significantly different after 61 h (primary outcome, mean individual change: −12%, p = 0.36, paired t-test), we detected 1.47-fold higher copeptin concentrations during arterial hypotension when compared to normotension (mixed-effect ANOVA, p = 0.01). In total, 8 out of 34 patients (23.5%) with low copeptin concentrations <10 pmol/L were hypotensive. Copeptin was highest in the adjusted mixed-effect regression analysis within the first day (+20% at 14 h) and decreased significantly at 108 h (−27%) compared to baseline (p = 0.002). Moreover, we found a significant association with vasopressor-inotrope treatment intensity, infancy (1−12 months) and cardiopulmonary bypass (all p ≤ 0.001). In conclusion, high copeptin values were associated with arterial hypotension and severity of disease in critically ill children. This study does not support the hypothesis that low copeptin values might be indicative of arginine-vasopressin deficiency.

Copeptin: Utility in Paediatric Patients with Hyponatraemia

INTRODUCTION

Copeptin concentrations are a useful component of the diagnostic workup of paediatric patients with polyuria and polydipsia, but the value of measuring copeptin in patients with hyponatraemia is less clear.

CASE REPORTS

We report 5 children with hyponatraemia in the context of different underlying pathologies. Copeptin concentrations were elevated in 4 cases (13.7, 14.4, 26.1, and 233 pmol/L; reference range 2.4-8.6 pmol/L), suggesting that non-osmoregulated vasopressin release (syndrome of inappropriate antidiuretic hormone) was the underlying mechanism for low sodium levels. In one of the patients, there was an underlying diagnosis of Schaaf-Yang syndrome (MAGEL2 gene mutation) with a clinical picture suggestive of dysregulated vasopressin production with inappropriately high and then low copeptin release. In one hyponatraemic patient, low copeptin concentrations indicated that non-osmoregulated arginine vasopressin release was not the cause of hyponatraemia and oliguria.

DISCUSSION

Copeptin measurement did not influence management acutely but helped to clarify the mechanism leading to hyponatraemia when the result was available. Relatively high and low copeptin concentrations in association with hypo- and hypernatraemia indicate dysregulated vasopressin production in Schaaf-Yang syndrome.

The kinetic profiles of copeptin and mid regional proadrenomedullin (MR-proADM) in pediatric lower respiratory tract infections

Background

Kinetics of copeptin and mid regional proadrenomedullin (MR-proADM) during febrile pediatric lower respiratory tract infections (LRTI) are unknown. We aimed to analyze kinetic profiles of copeptin and MR-proADM and the impact of clinical and laboratory factors on those biomarkers.

Methods

This is a retrospective post-hoc analysis of a randomized controlled trial, evaluating procalcitonin guidance for antibiotic treatment of LRTI (ProPAED-study). In 175 pediatric patients presenting to the emergency department plasma copeptin and MR-proADM concentrations were determined on day 1, 3, and 5. Their association with clinical characteristics and other inflammatory biomarkers were tested by non-linear mixed effect modelling.

Results

Median copeptin and MR-proADM values were elevated on day 1 and decreased during on day 3 and 5 (-26%; -34%, respectively). The initial concentrations of MR-proADM at inclusion were higher in patients receiving antibiotics intravenously compared to oral administration (difference 0.62 pmol/L, 95%CI 0.44;1.42, p<0.001). Intensive care unit (ICU) admission was associated with a daily increase of MR-proADM (increase/day 1.03 pmol/L, 95%CI 0.43;1.50, p<0.001). Positive blood culture in patients with antibiotic treatment and negative results on nasopharyngeal aspirates, or negative blood culture were associated with a decreasing MR-proADM (decrease/day -0.85 pmol/L, 95%CI -0.45;-1.44), p<0.001).

Conclusion

Elevated MR-proADM and increases thereof were associated with ICU admission suggesting the potential as a prognostic factor for severe pediatric LRTI. MR-proADM might only bear limited value for decision making on stopping antibiotics due to its slow decrease. Copeptin had no added value in our setting.

Prognostic value of pro-adrenomedullin and copeptin in acute infective endocarditis

Background

Infective endocarditis (IE) is a life-threatening disease whose prognosis is often difficult to predict based on clinical data. Biomarkers have been shown to favorably affect disease management in a number of cardiac disorders. Aims of this retrospective study were to assess the prognostic role of procalcitonin (PCT), pro-adrenomedullin (pro-ADM) and copeptin in IE and their relation with disease characteristics and the traditional biomarker C-reactive protein (CRP).

Methods

We studied 196 patients with definite IE. Clinical, laboratory and echocardiography parameters were analyzed, with a focus on co-morbidities. PCT, pro-ADM and copeptin were measured on stored plasma samples obtained on admission during the acute phase of the disease.

Results

Pro-ADM and copeptin were significantly higher in older patients and associated with prior chronic kidney disease. Pro-ADM was an independent predictor of hospital mortality (OR 3.29 [95%C.I. 1.04–11.5]; p = 0.042) whilst copeptin independently predicted 1-year mortality (OR 2.55 [95%C.I. 1.18–5.54]; p = 0.017). A high PCT value was strictly tied with S. aureus etiology (p = 0.001). CRP was the only biomarker associated with embolic events (p = 0.003).

Conclusions

Different biomarkers correlate with distinct IE outcomes. Pro-ADM and copeptin may signal a worse prognosis of IE on admission to the hospital and could be used to identify patients who need more aggressive treatment. CRP remains a low-cost marker of embolic risk. A high PCT value should suggest S. aureus etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-020-05655-7.

Distribution of plasma copeptin levels and influence of obesity in children and adolescents

In recent years, a more stable AVP surrogate, called copeptin, has been used as an adjuvant diagnostic tool for dysnatremia in adults and appears to be promising even in the pediatric age. The aim of this study is to present the distribution of plasma copeptin in a large pediatric cohort and to observe the influence of fluid consumption and obesity on its values. A cohort of 128 children and adolescents was divided into two groups on the basis of nocturnal deprivation (group A) or free access to oral fluids in the 6-8 h before blood collection (group B). At all distribution percentiles, copeptin levels were higher (p < 0.0001) in group A, as were plasma sodium levels and osmolality (p = 0.02 and p = 0.008, respectively). The influence of BMI on copeptin levels was investigated by dividing the cohort into nonobese (group C) and obese children and adolescents (group D). Copeptin levels were higher in group D (p = 0.04).Conclusion: The measurement of copeptin could represent a useful tool for the diagnostic pathway of dysnatremic conditions, but its interpretation should take into consideration the state of hydration. Furthermore, it could also be a promising marker for obesity and metabolic syndrome, although this hypothesis needs further studies to be confirmed. What is Known: • Copeptin use as a diagnostic tool in AVP-related disorders, such as diabetes insipidus or syndrome of inappropriate secretion of antidiuretic hormone, is well established in adults • In pediatric age, few studies are available, but the preliminary data, including our previous study, seems to be promising. What is New: • In this study, we represent the distribution of copeptin levels in a pediatric cohort and show the significant influence of fluid ingestion on its plasma levels. • Also BMI seems to be a significant variable on copeptin levels and may be used as an obesity marker in pediatric age.

Copeptin concentration following cardiac surgery as a prognostic marker of postoperative acute kidney injury: a prospective cohort study

Background

Copeptin, the C-terminal portion of the arginine vasopressin precursor, is a novel candidate biomarker. This study investigated the prognostic value of copeptin levels following cardiac surgery for the occurrence of postoperative acute kidney injury.

Methods

We studied 23 patients who underwent cardiac surgery between January 2018 and December 2019. The primary endpoint was postoperative acute kidney injury onset. Copeptin levels were measured before, right after, and daily for 7 days. The patients were divided into two groups according to the copeptin levels: low (values <43.7 pmol/L) and high (values ≥43.7 pmol/L). Correlations between copeptin levels and variables, such as central venous pressure, were assessed by bivariate analysis.

Results

The high copeptin group exhibited significantly higher levels of arginine vasopressin and cortisol following surgery, compared to those of the low copeptin group. The copeptin concentration following surgery was correlated to central venous pressure (P=0.03) and norepinephrine administered dose (P=0.008). Also, the copeptin levels right after surgery robustly predicted the onset of postoperative acute kidney injury (area under the receiver operating characteristic curve of 0.83, P=0.004).

Conclusions

Elevated copeptin levels in patients following cardiac surgery predicted postoperative acute kidney injury development. Therefore, the copeptin concentration after surgery could represent a promising clinical biomarker of the postoperative cardiac outcome.

The role of oxytocin and vasopressin in the pathophysiology of heart failure in pregnancy and in fetal and neonatal life

Pregnancy and early life create specific psychosomatic challenges for the mother and child, such as changes in hemodynamics, resetting of the water-electrolyte balance, hypoxia, pain, and stress, that all play an important role in the regulation of the release of oxytocin and vasopressin. Both of these hormones regulate the water-electrolyte balance and cardiovascular functions, maturation of the cardiovascular system, and cardiovascular responses to stress. These aspects may be of particular importance in a state of emergency, such as hypertension in the mother or severe heart failure in the child. In this review, we draw attention to a broad spectrum of actions exerted by oxytocin and vasopressin in the pregnant mother and the offspring during early life. To this end, we discuss the following topics: 1) regulation of the secretion of oxytocin and vasopressin and expression of their receptors in the pregnant mother and child, 2) direct and indirect effects of oxytocin and vasopressin on the cardiovascular system in the healthy mother and fetus, and 3) positive and negative consequences of altered secretion of oxytocin and vasopressin in the mother with cardiovascular pathology and in the progeny with heart failure. The present survey provides evidence that moderate stimulation of the oxytocin and vasopressin receptors plays a beneficial role in the healthy pregnant mother and fetus; however, under pathophysiological conditions the inappropriate action of these hormones exerts several negative effects on the cardiovascular system of the mother and progeny and may potentially contribute to the pathophysiology of heart failure in early life.

Copeptin role in polyuria-polydipsia syndrome differential diagnosis and reference range in paediatric age

OBJECTIVE

Plasma arginine-vasopressin (AVP) analysis can help in the differential diagnosis of the polyuria-polydipsia syndrome (PPS), even if such investigation is hampered by technical difficulties, conversely to its surrogate copeptin. This study aims to enlarge the existing data on normal copeptin levels in childhood, to evaluate the correlation between copeptin, serum sodium and plasma and urine osmolality, and to assess the utility of the copeptin analysis in the diagnostic work-up of PPS in the paediatric age.

PATIENTS AND METHODS

Plasma copeptin levels were evaluated in 53 children without AVP disorders (control population), in 12 hypopituitaric children and in 15 patients with PPS after water deprivation test (WDT).

RESULTS

Mean basal copeptin levels were 5.2 ± 1.56 (range 2.4-8.6 pmol/L) in the control population, 2.61 ± 0.49 pmol/L in the hypopituitaric children with complete diabetes insipidus (CDI) (P = .04) and 6.21 ± 1.17 pmol/L in the hypopituitaric patients without DI (P = .02). After WDT, among 15 naïve polyuric/polydipsic children, copeptin values greater than 20 pmol/L allowed to identify nephrogenic diabetes insipidus (NDI), concentrations below 2.2 pmol/L complete central DI (CCDI) and between 5 and 20 pmol/L primary polydipsia (PP). Copeptin cut-off level of 3.5 pmol/L distinguished CDI from PP, with a sensitivity and specificity of 75% and 83.3%, respectively.

CONCLUSION

Copeptin evaluation holds promises as a diagnostic tool in paediatric PPS; its interpretation might be useful to promptly distinguish NDI, even avoiding the WDT need.

Update on pediatric sepsis: a review

BACKGROUND

Sepsis is one of the leading causes of mortality among children worldwide. Unfortunately, however, reliable evidence was insufficient in pediatric sepsis and many aspects in clinical practice actually depend on expert consensus and some evidence in adult sepsis. More recent findings have given us deep insights into pediatric sepsis since the publication of the Surviving Sepsis Campaign guidelines 2012.

MAIN TEXT

New knowledge was added regarding the hemodynamic management and the timely use of antimicrobials. Quality improvement initiatives of pediatric "sepsis bundles" were reported to be successful in clinical outcomes by several centers. Moreover, a recently published global epidemiologic study (the SPROUT study) did not only reveal the demographics, therapeutic interventions, and prognostic outcomes but also elucidated the inappropriateness of the current definition of pediatric sepsis.

CONCLUSIONS

With these updated knowledge, the management of pediatric sepsis would be expected to make further progress. In addition, it is meaningful that the fundamental data on which future research should be based were established through the SPROUT study.

Host response biomarkers in the diagnosis of sepsis: a general overview

Critically ill patients who display a systemic inflammatory response syndrome (SIRS) are prone to develop nosocomial infections. The challenge remains to distinguish as early as possible among SIRS patients those who are developing sepsis. Following a sterile insult, damage-associated molecular patterns (DAMPs) released by damaged tissues and necrotic cells initiate an inflammatory response close to that observed during sepsis. During sepsis, pathogen-associated molecular patterns (PAMPs) trigger the release of host mediators involved in innate immunity and inflammation through identical receptors as DAMPs. In both clinical settings, a compensatory anti-inflammatory response syndrome (CARS) is concomitantly initiated. The exacerbated production of pro- or anti-inflammatory mediators allows their detection in biological fluids and particularly within the bloodstream. Some of these mediators can be used as biomarkers to decipher among the patients those who developed sepsis, and eventually they can be used as prognosis markers. In addition to plasma biomarkers, the analysis of some surface markers on circulating leukocytes or the study of mRNA and miRNA can be helpful. While there is no magic marker, a combination of few biomarkers might offer a high accuracy for diagnosis.

Copeptin as a serum biomarker of febrile seizures

Background and Objectives

Accurate diagnosis of febrile seizures in children presenting after paroxysmal episodes associated with fever, is hampered by the lack of objective postictal biomarkers. The aim of our study was to investigate whether FS are associated with increased levels of serum copeptin, a robust marker of arginine vasopressin secretion.

Methods

This was a prospective emergency-setting cross-sectional study of 161 children between six months and five years of age. Of these, 83 were diagnosed with febrile seizures, 69 had a febrile infection without seizures and nine had epileptic seizures not triggered by infection. Serum copeptin and prolactin levels were measured in addition to standard clinical, neurophysiological, and laboratory assessment. Clinical Trial Registration: NCT01884766.

Results

Circulating copeptin was significantly higher in children with febrile seizures (median [interquartile range] 18.9 pmol/L [8.5-36.6]) compared to febrile controls (5.6 pmol/L [4.1-9.4]; p <0.001), with no differences between febrile and epileptic seizures (21.4 pmol/L [16.1-46.6]; p = 0.728). In a multivariable regression model, seizures were the major determinant of serum copeptin (beta 0.509; p <0.001), independently of clinical and baseline laboratory indices. The area under the receiver operating curve for copeptin was 0.824 (95% CI 0.753-0.881), significantly higher compared to prolactin (0.667 [0.585-0.742]; p <0.001). The diagnostic accuracy of copeptin increased with decreasing time elapsed since the convulsive event (at 120 min: 0.879 [0.806-0.932] and at <60 min: 0.975 [0.913-0.997]).

Conclusions

Circulating copeptin has high diagnostic accuracy in febrile seizures and may be a useful adjunct for accurately diagnosing postictal states in the emergency setting.

Prognostic significance of hypothalamic-pituitary-adrenal axis hormones in early sepsis: a study performed in the emergency department

PURPOSE

The response of the hypothalamic-pituitary-adrenal (HPA) axis to the sustained stress of sepsis has been the focus of study in recent years because the early phase of sepsis is known to be dominated by major alterations in the HPA axis. This prospective observational study aimed at assessing the predictive values of copeptin and HPA hormones in determining sepsis progression and mortality in the emergency department (ED).

METHODS

Serum arginine vasopressin (AVP) and copeptin concentrations were measured upon ED admission. Baseline levels of total and free cortisol and adrenocorticotrophic hormone (ACTH) were measured within 24 h of ED admission. Mortality in Emergency Department Sepsis (MEDS) score was calculated at enrollment.

RESULTS

Our findings demonstrated that serum copeptin, baseline total cortisol, baseline free cortisol and baseline ACTH concentrations gradually increased, based upon the increasing severity of the disease (p < 0.001). Multivariate logistic regression analysis showed that copeptin and total cortisol baseline concentrations were independent predictors of septic shock (odds ratio = 1.034 and 1.355, respectively) and 28-day mortality (odds ratio = 1.039 and 1.499, respectively). The areas under the receiver operating characteristic curve (AUC) for copeptin level in prediction of septic shock was 0.856 and 28-day mortality was 0.826. Importantly, AUC analysis of the combination of copeptin, total cortisol baseline, MEDS score, and procalcitonin level resulted in a more significant prognostic ability than analysis of each parameter alone (p < 0.001).

CONCLUSIONS

Increased copeptin and HPA hormones baseline levels may provide crucial information for risk stratification in a variety of septic states in the ED. Furthermore, measurements of copeptin level and serum baseline cortisol concentration are promising independent prognostic markers for mortality in patients with severe sepsis or septic shock.

Copeptin as a diagnostic biomarker for sepsis-related deaths

Copeptin has been shown to increase in patients with sepsis, severe sepsis and septic shock. In the study herein described, copeptin was measured in a series of sepsis-related fatalities and control cases that underwent medico-legal investigations. No age-dependent differences in copeptin levels in either sepsis or control cases were observed. No correlation between copeptin concentrations and postmortem interval was identified in either group. Copeptin levels were significantly higher in sepsis cases. Moreover, copeptin concentrations in septic cases correlated with procalcitonin, C-reactive protein and interleukin 6 values. These preliminary findings seem to indicate that copeptin can be reliably measured in biological samples collected during postmortem investigations. These results also suggest that hemodynamic instability associated with sepsis and septic shock can be characterized by copeptin measurement also in the forensic casework.

Postoperative plasma copeptin levels independently predict delirium and cognitive dysfunction after coronary artery bypass graft surgery

Copeptin can reflect individual's stress state and are correlated with poor outcome of critical illness. The occurrence of postoperative delirium (POD) and cognitive dysfunction (POCD) is associated with worse outcome after coronary artery bypass graft (CABG) surgery. The present study aimed to investigate the ability of postoperative plasma copeptin level to predict POD and POCD in patients undergoing CABG surgery. Postoperative plasma copeptin levels of 108 patients were measured by an enzyme-linked immunosorbent assay. It was demonstrated that plasma copeptin levels were substantially higher in patients with POD than without POD (1.8±0.6 ng/mL vs. 1.1±0.3 ng/mL; P<0.001) and in patients with POCD than without POCD (1.9±0.6 ng/mL vs. 1.1±0.4 ng/mL; P<0.001). Plasma copeptin level and age were identified as independent predictors for POD [odds ratio (OR), 67.386; 95% confidence interval (CI), 12.031-377.426; P<0.001 and OR, 1.202; 95% CI, 1.075-1.345; P=0.001] and POCD (OR, 28.814; 95% CI, 7.131-116.425; P<0.001 and OR, 1.151; 95% CI, 1.030-1.285; P=0.003) using a multivariate analysis. For prediction of POD, the area under receiver operating characteristic curve (AUC) of the copeptin concentration (AUC, 0.883; 95% CI, 0.807-0.937) was markedly higher than that of age (AUC, 0.746; 95% CI, 0.653-0.825; P=0.020). For prediction of POCD, the AUC of the copeptin concentration (AUC, 0.870; 95% CI, 0.792-0.927) was markedly higher than that of age (AUC, 0.735; 95% CI, 0.641-0.815; P=0.043). Thus, postoperative plasma copeptin level may be a useful, complementary tool to predict POD and POCD in patients undergoing CABG surgery.

Cellular bioenergetics changes in magnocellular neurons may affect copeptin expression in the late phase of sepsis

We investigated whether inflammatory mediators during cecal ligation and puncture (CLP)-induced sepsis may diminish copeptin expression in magnocellular neurons, thus affecting arginine-vasopressin (AVP) synthesis. The transcript abundance of IL-1β, IL-1R1, iNOS and HIF-1α was continuously elevated. IL-1β, iNOS and cytochrome c protein levels progressively increased until 24h. Immunostaining for these proteins was higher at 6 and 24h, as also seen in the annexin-V assay, while copeptin was continuously decreased. This suggests that increased IL-1β and NO levels may cause significant bioenergetics changes in magnocellular neurons, affecting copeptin expression and compromising AVP synthesis and secretion in the late phase of sepsis.