Plasma copeptin and metabolic dysfunction in individuals with bipolar disorder

• Published in: Psychiatry and clinical neurosciences Vol. 71; no. 9; pp. 624 - 636
• Main Authors: Mansur, Rodrigo B., Rizzo, Lucas B., Santos, Camila M., Asevedo, Elson, Cunha, Graccielle R., Noto, Mariane N., Pedrini, Mariana, Zeni‐Graiff, Maiara, Cordeiro, Quirino, McIntyre, Roger S., Brietzke, Elisa
• Format: Journal Article
• Language: English
• Published: Melbourne John Wiley & Sons Australia, Ltd 01-09-2017; Wiley Subscription Services, Inc
• Subjects: Adiponectin; Adult; Beta cells; Bipolar disorder; Bipolar Disorder - blood; Bipolar Disorder - epidemiology; Body mass; Body mass index; Comorbidity; copeptin; Diabetes; Diabetes mellitus; Diabetes Mellitus, Type 2 - blood; Diabetes Mellitus, Type 2 - epidemiology; Dyslipidemias - blood; Dyslipidemias - epidemiology; Enzyme-linked immunosorbent assay; Fasting; Female; Glucose metabolism; Glycopeptides - blood; Humans; Insulin; Insulin resistance; Leptin; Male; Metabolism; Middle Aged; Plasma levels; Prediabetic State - blood; Prediabetic State - epidemiology; vasopressin; copeptin; bipolar disorder; metabolism; insulin resistance; vasopressin
• ISSN: 1323-1316; 1440-1819
• DOI: 10.1111/pcn.12535

Aim
This study aimed to compare plasma copeptin levels, the c‐terminal of provasopressin, between individuals with bipolar disorder (BD) and healthy controls and to assess the relation between copeptin and metabolic parameters.
Methods
We measured plasma levels of copeptin in individuals with BD (n = 55) and healthy controls (n = 21). Information related to psychiatric/medical history, as well as to metabolic comorbidities and laboratorial parameters was also captured. Insulin resistance and β‐cell function in basal state were calculated from fasting plasma glucose and C‐peptide using the HOMA2 calculator. Impaired glucose metabolism was defined as pre‐diabetes or type 2 diabetes mellitus. Copeptin, adiponectin, and leptin plasma levels were determined by enzyme‐linked immunosorbent assay.
Results
Plasma copeptin levels were lower in individuals with BD, relative to healthy controls (P < 0.001). There were significant interactions between BD and plasma copeptin on β‐cell function (rate ratio [RR] = 1.048; P = 0.030) and on leptin levels (RR = 1.087; P = 0.012), indicating that there was a positive correlation between these markers in the BD group, but a negative one in healthy controls. Finally, in individuals with BD only, the association between β‐cell function, body mass index (RR = 1.007; P < 0.001), and insulin resistance (RR = 1.001; P = 0.037) was moderated by copeptin levels.
Conclusion
Copeptin levels were lower in individuals with BD than in healthy controls. There were differential associations between copeptin and metabolic parameters within the BD and healthy control subgroups, suggesting an association between abnormal copeptin and metabolic dysregulation only in the BD population.