The Role of Zinc in Developed Countries in Pediatric Patients: A 360-Degree View

Zinc is an important trace element for growth and health at pediatric ages. Zinc is fundamental in inflammatory pathways, oxidative balance, and immune function. Zinc exhibits anti-inflammatory properties by modulating Nuclear Factor-kappa (NF-κB) activity and reducing histamine release from basophils, leukocytes, and mast cells. Furthermore, its antioxidant activity protects against oxidative damage and chronic diseases. Finally, zinc improves the ability to trigger effective immune responses against pathogens by contributing to the maturation of lymphocytes, the production of cytokines, and the regulation of apoptosis. Given these properties, zinc can be considered an adjunctive therapy in treating and preventing respiratory, nephrological, and gastrointestinal diseases, both acute and chronic. This review aims to deepen the role and metabolism of zinc, focusing on the role of supplementation in developed countries in pediatric diseases.

Pathophysiology of Major Depression by Clinical Stages

The comprehension of the pathophysiology of the major depressive disorder (MDD) is essential to the strengthening of precision psychiatry. In order to determine the relationship between the pathophysiology of the MDD and its clinical progression, analyzed by severity of the depressive symptoms and sleep quality, we conducted a study assessing different peripheral molecular biomarkers, including the levels of plasma C-reactive protein (CRP), serum mature brain-derived neurotrophic factor (mBDNF), serum cortisol (SC), and salivary cortisol awakening response (CAR), of patients with MDD (n = 58) and a control group of healthy volunteers (n = 62). Patients with the first episode of MDD (n = 30) had significantly higher levels of CAR and SC than controls (n = 32) and similar levels of mBDNF of controls. Patients with treatment-resistant depression (TRD, n = 28) presented significantly lower levels of SC and CAR, and higher levels of mBDNF and CRP than controls (n = 30). An increased severity of depressive symptoms and worse sleep quality were correlated with levels low of SC and CAR, and with high levels of mBDNF. These results point out a strong relationship between the stages clinical of MDD and changes in a range of relevant biological markers. This can assist in the development of precision psychiatry and future research on the biological tests for depression.

Is Riparin III a promising drug in the treatment for depression?

Stress is crucially related to the pathophysiology of mood disorders, including depression. Since the effectiveness and number of the current pharmacological options still presents significant limitations, research on new substances is paramount. In rodents, several findings have indicated that corticosterone administration induces the manifestation of behavioral and neurochemical aspects of depression. Recently, riparin III has shown antidepressant-like properties in trials performed on animal models. Thus, our goal was to investigate the effects of riparin III on behavioral tests, monoamines levels, oxidative stress and cytokines levels in chronic corticosterone-induced model of depression. To do this, female swiss mice were treated with subcutaneous administration of corticosterone for 22 days. In addition, for the last 10 days, riparin III or fluvoxamine were also administered per os in specific test groups. Control groups received subcutaneous saline injections or distilled water per os. At the end of the timeline, the animals were killed and their hippocampi, prefrontal cortex, and striatum dissected for neurochemical analysis. Brain changes following corticosterone administration were confirmed, and riparin III could reversed the most abnormal behavioral and neurochemical corticosterone-induced alterations. These results suggest the potential antioxidant, anti-inflammatory and antidepressant effects of riparin III after a chronic stress exposure.

Influence of excessive daily sleeping and sleep quality on BDNF and NGF serum levels in adolescents

INTRODUCTION

The brain-derived neurotrophic factor (BDNF) and neural growth factor (NGF) are widely expressed in the brain and play an important role in neuroplasticity, neurogenesis, and increased neuronal connections. Previous studies have shown that reduced serum levels of these proteins are associated with disorders in human sleep.

OBJECTIVE

Current study evaluates the prevalence in adolescents of excessive daytime sleepiness (EDS) and sleep quality, and analyzes the influence of these factors on BDNF and NGF serum levels.

METHODS

A cross-section population-based study was conducted with data from a Brazilian birth cohort, with a sample of five hundred and thirteen 18-19-year-old adolescents. Sleep quality was assessed by the Pittsburgh Sleep Quality Index and EDS by Epworth Sleepiness Scale. Neurotrophins serum levels were measured by Luminex™ technology kits. Analysis consisted of marginal structural models which compared people who were exposed and not exposed to sleep quality and EDS.

RESULTS

Poor sleep quality and EDS were detected in 62.57% and 36.35% of the sample. Adolescents with poor sleep quality and EDS had -0.39 (p-value = 0.049) and -0.51 pg/ml in NGF (p-value = 0.009). Individuals with self-reported sleep disorder had lower serum levels of NGF (Coef. -0.41, p-value = 0.045).

CONCLUSION

High prevalence of EDS and low sleep quality in a population of adolescents were evidenced. Poor sleep quality and EDS were associated with lower NGF levels, whilst adolescents with self-reported sleep disorder had lower serum levels of NGF.

Zinc supplementation combined with antidepressant drugs for treatment of patients with depression: a systematic review and meta-analysis

CONTEXT

Zinc is an essential trace mineral required for the function of brain and neural structures. The role of zinc supplementation in the prevention and treatment of depression has been suggested in clinical studies that reported a reduction in depressive symptoms.

OBJECTIVE

The aim of this review was to determine whether zinc supplementation vs placebo can prevent or improve depressive symptoms in children, adolescents, or adults.

DATA SOURCES

Five electronic databases were searched, and studies published until September 2019 were included without language restriction.

STUDY SELECTION

Randomized, controlled, crossover trials that evaluated the effect of zinc supplementation vs a comparator for prevention or improvement of depressive symptoms in children, adolescents, or adults were eligible for inclusion.

DATA EXTRACTION

Two authors independently performed data extraction and risk-of-bias assessment.

RESULTS

The initial search identified 12 322 studies, 5 of which were eligible for meta-analysis. The standardized mean difference (SMD) showed an average reduction of 0.36 point (95%CI, -0.67 to -0.04) in the intervention group compared with the placebo group. Forstudies in which the mean age of participants was ≥ 40 years, the SMD was reduced by 0.61 point (95%CI, -1.12 to -0.09) in the intervention group vs the placebo group. The meta-analysis by sample size (< 60 individuals and  ≥ 60 individuals) did not show an effect of zinc supplementation in reducing depressive symptoms (SMD -0.28; 95%CI, -0.67 to -0.10; and SMD -0.52; 95%CI, -1.10 to 0.06).

CONCLUSION

Zinc supplementation may reduce depressive symptoms in individuals treated with antidepressant drugs for clinical depression.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42018081691.