Different effects on zinc redistribution if ethanol is consumed before or immediately after birth

Contribution of ferritin and zinc to adverse infant outcomes among pregnancies with prenatal alcohol exposure in South Africa

Nutritional status during pregnancy can impact fetal development, yet less is known about how alcohol may interact with nutritional status to influence infant outcomes. Pregnant women (n=196) completed 2, 24-hour dietary recalls and provided a venous blood sample to be analyzed for liver enzymes (GGT -gamma-glutamyl transferase; ALT -alanine transaminase; and AST -aspartate transferase), iron, ferritin, and zinc concentrations. Infants were assessed at 6 weeks of age. Women who consumed alcohol had significantly higher ferritin levels compared to non-drinkers (51.8 vs. 34.2). While 44% of women had ferritin <30 ug/L (an indicator of iron deficiency), and 24% of women were low in serum iron, and 72% were low in serum zinc. All six drinking measures for 1st trimester and previous week were significantly correlated with GGT and AST levels while 4 out of 6 alcohol measures were associated with levels of ALT and ferritin. At six weeks of age, nearly all physical measures differentiated infants with alcohol exposure from infants without exposure. Controlling for six covariates, maternal ferritin was significantly and inversely associated with infant head circumference (OFC) centile among infants with alcohol exposure. GGT was inversely associated with infant height and weight centile among unexposed infants. Seventy-four percent (74%) of mothers who consumed alcohol were found to be low in serum zinc, yet higher maternal zinc was associated with more dysmorphology. This may indicate that higher zinc status is not protecting the fetus from the teratogenic effects of alcohol. Prenatal alcohol exposure, ferritin, and zinc status influence infant growth and neurodevelopment.

Zinc deficiency as a mediator of toxic effects of alcohol abuse

OBJECTIVE

To review data on the role of ethanol-induced alteration of Zn homeostasis in mediation of adverse effects of alcohol abuse.

METHODS

The scholarly published articles on the association between Zn metabolism and alcohol-associated disorders (liver, brain, lung, gut dysfunction, and fetal alcohol syndrome) have been reviewed.

RESULTS

It is demonstrated that alcohol-induced modulation of zinc transporters results in decreased Zn levels in lungs, liver, gut, and brain. Zn deficiency in the gut results in increased gut permeability, ultimately leading to endotoxemia and systemic inflammation. Similarly, Zn deficiency in lung epithelia and alveolar macrophages decreases lung barrier function resulting in respiratory distress syndrome. In turn, increased endotoxemia significantly contributes to proinflammatory state in alcoholic liver disease. Finally, impaired gut and liver functions may play a significant role in alcoholic brain damage, being associated with both increased proinflammatory signaling and accumulation of neurotoxic metabolites. It is also hypothesized that ethanol-induced Zn deficiency may interfere with neurotransmission. Similar changes may take place in the fetus as a result of impaired placental zinc transfer, maternal zinc deficiency, or maternal Zn sequestration, resulting in fetal alcoholic syndrome. Therefore, alcoholic Zn deficiency not only mediates the adverse effects of ethanol exposure, but also provides an additional link between different alcohol-induced disorders.

CONCLUSIONS

Generally, current findings suggest that assessment of Zn status could be used as a diagnostic marker of metabolic disturbances in alcohol abuse, whereas modulation of Zn metabolism may be a potential tool in the treatment of alcohol-associated disorders.

Metallothioneins pattern during ontogeny of coastal dolphin, Pontoporia blainvillei, from Argentina

Metallothioneins are signals of metal exposure and widely used in biomonitoring. Franciscana dolphin is an endemic cetacean from the Southwestern Atlantic Ocean, classified as Vulnerable A3d by the IUCN. Metallothionein, copper and zinc in Franciscana were assessed in two geographic groups; one inhabits La Plata River estuary, anthropogenically impacted, and the other inhabits marine coastal ecosystems, with negligible pollution. Despite the environment, hepatic and renal MT concentrations were similar, but there was a declining trend from early to later developmental stages. Metallothionein K/L, Cu and Zn levels corresponded to normal reported ranges. MT was not related with Cd. Fetal concentrations were higher than its mother. These results and the health status of dolphins are suggesting that MT correspond to physiological ranges for the species, and they are closely to homeostasis of Zn and Cu, according to its ontogenetic changes. The information constitutes the first MT information on Franciscana dolphin and can be considered as baseline for the species conservation.

Ethanol reduces zincosome formation in cultured astrocytes

AIMS

Zinc is an ion that participates in basic cellular and tissular functions. Zinc deficiency is present in many physiological and health problems affecting most body organs, including the brain. Among the circumstances involved in zinc deficiency, ethanol consumption is probably one of the most frequent. A dietary zinc supplement has been proposed as possibly being an efficient method to palliate zinc deficiency. Astrocytes form part of the hematoencephalic barrier, and they are apparently implicated in the homeostasis of the neuronal medium. In this work, we analyze the effect of ethanol on extracellular zinc management by rat astrocytes in culture.

METHODS

Intracellular levels of 'free zinc ions', in controls and 30 mM ethanol-treated astrocytes, were visualized by using the zinc fluorochrome TSQ. Cytoplasmic fluorescence and zincosome formation were measured after adding extracellular 50 µM ZnSO(4) to cell monolayers. Zincosomes were also observed at the electron microscopy level.

RESULTS

Exposure to ethanol for 7 days lowered the basal zinc levels of astrocytes by ∼30%. This difference was consistently maintained after the zinc pulse. Zinc ions were confined to bright fluorescent particles, the 'zincosomes', which appeared to be formed by the endocytic pathway. Zincosomes were less abundant in alcohol-treated cells, indicating a deficit in endocytoses as the origin of low zinc intake in astrocytes after ethanol treatment.

CONCLUSIONS

Ethanol reduces both intracellular ionic zinc levels and extracellular zinc uptake, resulting in poorer zincosome formation. Given the endocytic nature of zincosomes, the effect of ethanol on membrane trafficking is apparently the origin of this deficit.