Assessment of serum levels of copeptin and corticotropin-releasing factor in children with monosymptomatic and non-monosymptomatic nocturnal enuresis.
BACKGROUND
Nocturnal enuresis is defined as bed-wetting in children from the age of five years that occurs during sleep; if untreated, the condition can result in social and psychological problems both for the children and their parents. Nocturnal enuresis is a complicated disease that includes multiple pathogenetic factors. Nocturnal enuresis is divided into two subgroups: monosymptomatic and non-monosymptomatic. The role of some biomarkers in patients with monosymptomatic enuresis has been reported in a small number of the studies.


OBJECTIVE
The aim of this research was to evaluate the serum levels of copeptin and corticotropin-releasing factor (CRF) in monosymptomatic and non-monosymptomatic nocturnal enuresis cases. Although these markers were previously examined in children with monosymptomatic enuresis, there is no study that has evaluated these markers in non-monosymptomatic children.


STUDY DESIGN
One hundred nineteen children with nocturnal enuresis (5-16 years) and forty healthy children (5-17 years) were enrolled to the study. Of the nocturnal enuresis group, forty-nine were monosymptomatic and seventy were non-monosymptomatic. Copeptin and CRF were measured by a competitive inhibition method with enzyme-linked immunosorbent assay.


RESULTS
The serum copeptin levels were significantly lower in children with monosymptomatic and non-monosymptomatic nocturnal enuresis than in the controls.(median, 34.7 [interquartile range (IQR): 34 pg/ml], 39.8 [IQR: 29 pg/ml] vs 52.1 [IQR: 14 pg/ml], respectively, P < 0.05). The serum CRF levels were significantly lower in children with monosymptomatic and non-monosymptomatic nocturnal enuresis than in the controls (median, 35.1 [IQR: 19 pg/ml], 34.05 [IQR: 24 pg/ml] vs 78.3 [IQR: 39 pg/ml], respectively, P < 0.05). There was no significant difference in copeptin and CRF levels between the children with monosymptomatic and non-monosymptomatic nocturnal enuresis.


DISCUSSION
Copeptin is presumed to be a sensitive surrogate biomarker for arginine vasopressin release. To date, there are only two studies in the literature that assess the relationship between copeptin and monosymptomatic enuresis. The only study in the literature demonstrated significantly decreased levels of CRF in monosymptomatic enuretic children. It was demonstrated that the levels of copeptin and CRF differ in both children with monosymptomatic and non-monosymptomatic nocturnal enuresis from the control groups. It was also demonstrated that copeptin and CRF levels were not different between the children in monosymptomatic and non-monosymptomatic groups.


CONCLUSION
Those changes in both copeptin and CRF which were shown in this study in monosymptomatic and non-monosymptomatic enuretic children may contribute to the pathogenesis of nocturnal enuresis. Further case-control studies can evaluate the copeptin and CRF levels before treatments in monosymptomatic and non-monosymptomatic patients to decide potential effectiveness of treatment.