The influence of vasopressin deficiency and acute desmopressin administration on melatonin secretion in patients with central diabetes insipidus

Vasopressin as Possible Treatment Option in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is rather common, presenting with prevalent early problems in social communication and accompanied by repetitive behavior. As vasopressin was implicated not only in salt-water homeostasis and stress-axis regulation, but also in social behavior, its role in the development of ASD might be suggested. In this review, we summarized a wide range of problems associated with ASD to which vasopressin might contribute, from social skills to communication, motor function problems, autonomous nervous system alterations as well as sleep disturbances, and altered sensory information processing. Beside functional connections between vasopressin and ASD, we draw attention to the anatomical background, highlighting several brain areas, including the paraventricular nucleus of the hypothalamus, medial preoptic area, lateral septum, bed nucleus of stria terminalis, amygdala, hippocampus, olfactory bulb and even the cerebellum, either producing vasopressin or containing vasopressinergic receptors (presumably V1a). Sex differences in the vasopressinergic system might underline the male prevalence of ASD. Moreover, vasopressin might contribute to the effectiveness of available off-label therapies as well as serve as a possible target for intervention. In this sense, vasopressin, but paradoxically also V1a receptor antagonist, were found to be effective in some clinical trials. We concluded that although vasopressin might be an effective candidate for ASD treatment, we might assume that only a subgroup (e.g., with stress-axis disturbances), a certain sex (most probably males) and a certain brain area (targeting by means of virus vectors) would benefit from this therapy.

Efficacy and safety of desmopressin orally disintegrating tablet in patients with central diabetes insipidus: results of a multicenter open-label dose-titration study

Central diabetes insipidus (CDI) is associated with arginine vasopressin (AVP) deficiency with resultant polyuria and polydipsia. Intranasal desmopressin provides physiological replacement but oral formulations are preferred for their ease of administration. This study aimed to demonstrate the efficacy and safety of desmopressin orally disintegrating tablet (ODT) in the treatment of Japanese patients with CDI, and confirm that antidiuresis is maintained on switching from intranasal desmopressin to desmopressin ODT. A total of 20 patients aged 6-75 years with CDI were included in this 4-week multicenter, open-label study. Following observation, patients switched from intranasal desmopressin to desmopressin ODT with titration to optimal dose over ≤5 days at the study site. Following three consecutive doses with stable patient fluid balance, patients were discharged with visits at Weeks 2 and 4. Following titration from intranasal desmopressin to ODT, the mean 24-hour urine volume was unchanged, indicating similar antidiuresis with both formulations. The proportion of patients with endpoint measurements (urine osmolality, 24-hour urine volume, hourly diuresis rate and urine-specific gravity) within normal range at Days 1-2 (intranasal desmopressin) and Week 4 (desmopressin ODT) was similar. The mean daily dose ratio of intranasal desmopressin to desmopressin ODT (Week 4) was 1:24 but a wide range was observed across individuals to maintain adequate antidiuretic effect. Hyponatraemia was generally mild and managed by dose titration. Desmopressin ODT achieved sufficient antidiuretic control compared to intranasal therapy and was well tolerated over long-term treatment. The wide range of intranasal:ODT dose ratios underline the importance of individual titration.

Desmopressin increases IGF-binding protein-1 in humans

CONTEXT

IGF binding protein-1 (IGFBP-1) is essential for IGF-I bioavailability. High levels of IGFBP-1 are encountered in critically ill patients and are a good predictor marker in acute myocardial infarction. The mechanisms responsible for the elevated IGFBP-1 levels in these conditions are still unclear. Interestingly, high levels of vasopressin have been reported in the above-mentioned conditions.

OBJECTIVE

To study the effect of vasopressin on IGFBP-1 in humans.

DESIGN

Placebo-controlled cross-over study in patients with central diabetes insipidus (CDI) in whom potential interference from endogenous vasopressin secretion is minimized. After a 3-day desmopressin washout period, each patient received i.v. saline on day 1 and desmopressin (3 mug) on day 2. Blood samples were taken after administration, every 2 h during the whole night, starting at 2000 h.

PATIENTS AND SETTING

Fourteen inpatients with CDI in an endocrinology department of a university hospital.

RESULTS

Serum IGFBP-1 increased within 4 h after 1-desamino-8-d-arginine vasopressin (DDAVP) by 375+/-73%, compared with a spontaneous fasting increase by 252+/-46% following placebo administration (P<0.05). No changes were registered in the levels of either classically regulators of IGFBP-1 (insulin, glucagon, and cortisol) or of IGF-I and glucose. The decrease in plasma osmolarity induced by DDAVP did not precede the increase in IGFBP-1.

CONCLUSIONS

DDAVP increases serum levels of IGFBP-1. Further investigation is essential to unravel the clinical potential of this interaction in conditions associated with high IGFBP-1 levels.

A vasopressin/oxytocin-related conopeptide with gamma-carboxyglutamate at position 8

Vasopressins and oxytocins are homologous, ubiquitous and multifunctional peptides present in animals. Conopressins are vasopressin/oxytocin-related peptides that have been found in the venom of cone snails, a genus of marine predatory molluscs that envenom their prey with a complex mixture of neuroactive peptides. In the present paper, we report the purification and characterization of a unique conopressin isolated from the venom of Conus villepinii, a vermivorous cone snail species from the western Atlantic Ocean. This novel peptide, designated gamma-conopressin-vil, has the sequence CLIQDCPgammaG* (gamma is gamma-carboxyglutamate and * is C-terminal amidation). The unique feature of this vasopressin/oxytocin-like peptide is that the eighth residue is gamma-carboxyglutamate instead of a neutral or basic residue; therefore it could not be directly classified into either the vasopressin or the oxytocin peptide families. Nano-NMR spectroscopy of the peptide isolated directly from the cone snails revealed that the native gamma-conopressin-vil undergoes structural changes in the presence of calcium. This suggests that the peptide binds calcium, and the calcium-binding process is mediated by the gamma-carboxyglutamate residue. However, the negatively charged residues in the sequence of gamma-conopressin-vil may mediate calcium binding by a novel mechanism not observed in other peptides of this family.