Plasma leptin suppression by arginine vasopressin in normal women and men

The brain and immune system prompt energy shortage in chronic inflammation and ageing

Sequelae frequently seen in patients with chronic inflammatory diseases, such as fatigue, depressed mood, sleep alterations, loss of appetite, muscle wasting, cachectic obesity, bone loss and hypertension, can be the result of energy shortages caused by an overactive immune system. These sequelae can also be found in patients with chronic inflammatory diseases that are in remission and in ageing individuals, despite the immune system being less active in these situations. This Perspectives article proposes a new way of understanding situations of chronic inflammation (such as rheumatic diseases) and ageing based on the principles of evolutionary medicine, energy regulation and neuroendocrine-immune crosstalk. A conceptual framework is provided to enable physicians and scientists to better understand the signs and symptoms of chronic inflammatory diseases and long-term disease consequences resulting from physical and mental inactivity.

Plasma copeptin and metabolic dysfunction in individuals with bipolar disorder

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.

Comparison of the effects of proton pump inhibitors on human plasma adrenocorticotropic hormone and cortisol levels under the starved condition

The hypothalamo-pituitary-adrenal (HPA) axis is known to relate with energy homeostasis. Appetite and food intake are assumed to be regulated by the HPA axis. Among lots of medicines that act gastrointestinal system, we focused proton pump inhibitors, which are widely used to treat peptic ulcer, gastro esophageal reflux disease and eradication of Helicobacter pylori. In this study, we investigated that the effect of three proton pump inhibitors (omeprazole, lansoprazole and rabeprazole) on plasma adrenocorticotropic hormone (ACTH) and cortisol levels in healthy human subjects. Five healthy male volunteers were treated to omeprazole, lansoprazole, rabeprazole or placebo. Venous blood samples were taken repetitively from a forearm vein before and after administration. Plasma ACTH-like immunoreactive substance (IS) levels were measured using a sensitive enzyme immunoassay, and plasma cortisol levels were measured using a fluorescence polarization immunoassay. Single administration of lansoprazole caused significant (P<0.05) increase of ACTH-IS at 60 and 120-180 min, and cortisol at 180-240 min after administration, compared with placebo group. Rabeprazole also caused significant increase of ACTH-IS at 120 min and cortisol at 240-360 min, compared with placebo group. Omeprazole had no effect on plasma ACTH-IS and cortisol levels. Lansoprazole and rabeprazole increased plasma ACTH-IS and cortisol levels. Therefore, we hypothesized that the medicines might activate the HPA axis, and have effect to promote feeding. We considered that these results might be relevant to the development of new therapeutics in the treatment of psychiatric disorders involving dysregulation of appetite.

Sexual diergism of baseline plasma leptin and leptin suppression by arginine vasopressin in major depressives and matched controls

Leptin inhibits appetite by activating several neuroendocrine systems, including the hypothalamo-pituitary-adrenal cortical (HPA) axis. In turn, chronically elevated glucocorticoids increase circulating leptin. HPA axis hyperactivity occurs in 30-50% of patients with major depression, but the few prior reports of leptin measurements in this illness have shown inconsistent results. We, therefore, measured plasma leptin in 12 female and 8 male unipolar major depressives and 12 female and 8 male individually matched normal controls administered low-dose physostigmine (PHYSO) and arginine vasopressin (AVP) to stimulate the HPA axis. The subjects underwent four test sessions 5-7 days apart: PHYSO (8 microg/kg IV); AVP (0-08 U/kg IM); PHYSO+AVP; and saline control. Serial blood samples were taken before and after pharmacologic challenge and analyzed for leptin, ACTH(1-39), cortisol and AVP. Estradiol and testosterone also were measured at each test session. PHYSO and AVP produced no side effects in approximately half the subjects and predominantly mild side effects in the other half, with no significant patient-control differences. Correlations between side effects (absent or present) after PHYSO or AVP and the corresponding leptin responses were non-significant in all groups. Baseline plasma leptin concentrations (mean+/-S.D.) were significantly higher in the female patients compared to the female controls (22.5+/-13.9 ng/ml vs. 12.3+/-9.7 ng/ml), whereas they were similar in the male patients and the male controls (3.9+/-1.4 ng/ml vs. 3.6+/-2.0 ng/ml). Leptin concentrations following PHYSO remained unchanged from baseline, indicating that the short-lived ACTH and cortisol increases produced by PHYSO did not affect leptin secretion. In contrast, AVP administration, while also increasing ACTH and cortisol, significantly suppressed leptin, more so in the women than in the men. Baseline leptin and the leptin decrease after AVP were moderately positively correlated with the Hamilton Depression Scale 'somatization' factor in the female patients (r=0.50) and more strongly correlated with the 'mood-depression' factor in the male patients (r=0.81). These findings indicate a sexual diergism (functional sex difference) in plasma leptin measures between major depressives and matched normal controls.