Trace elements in bipolar disorder.

INTRODUCTION: Trace elements may play an important role in bipolar disorders. The objective of this study is to determine serum copper and zinc, blood lead and cadmium and urine lead, cadmium and thallium concentrations in patients diagnosed with bipolar disorders and to compare these levels with those of a healthy control group. MATERIALS AND METHODS: A total of 25 patients diagnosed with bipolar disorder and 29 healthy subjects participated in this study. Serum copper and zinc concentrations were measured using flame atomic absorption spectrometry; the blood lead and cadmium concentrations were measured by electrothermal atomization atomic absorption spectrometry with Zeeman background correction; urine lead, cadmium and thallium concentrations were measured by inductively coupled plasma mass spectrometry. RESULTS: Median blood and urine lead and cadmium levels were significantly higher among the bipolar patients than among the control group: Blood lead (µg/dL): patient median: 3.00 (IQR: 1.40-4.20); control median (µg/dL): 2.20 (IQR: 0.90-3.00) p=0.040. Blood cadmium (µg/L): patient median: 0.39 (IQR: 0.10-1.15); control median: 0.10 (IQR: 0.10-0.17) p<0.001. The median of cadmium (µg/L) in patients who smoked (1.20 IQR: 0.44-2.30) was higher than that in non-smokers (0.12 IQR: 0.10-0.34) p<0.001. There was a statistically significant increase (p=0.001) in zinc levels among patients in the manic phase (mean 111.28, SD: 33.36 µg/dL) with respect to the control group (mean 86.07, SD: 12.39 µg/dL). CONCLUSIONS: The results suggest that there could be higher levels of some toxic trace elements in the group of patients with bipolar disorder than in the healthy control group.

Measurement of cerium in human breast milk and blood samples.

The aim of this study was to evaluate the relationship between cerium content in human breast milk and blood plasma or serum. Blood samples and breast milk at various stages of lactation, from 5 days to 51 weeks post partum, were donated by 42 healthy breast-feeding mothers from Munich, Germany and by 26 lactating Spanish mothers from Madrid at 4 weeks post partum. Inductively coupled plasma mass spectrometry was applied for the determination of cerium in the biological samples. Cerium concentration in the digested milk samples from Munich showed low values and the arithmetic mean values ranged between the quantification limit of 5 ng/L up to 65 ng/L. The median value amounted to 13 ng/L. The cerium concentrations in the Spanish breast milk samples amounted to similar low values. The data were about a factor of eight lower than values found in a former study of samples from an eastern German province. All cerium concentrations in the German plasma samples, except for two, were at the quantification limit of 10 ng/L. Interestingly, the serum samples of the Spanish mothers showed cerium values ranging between 21.6 and 70.3 ng/L; these higher data could be explained by an enhanced intake of cerium by humans in Madrid. This could be caused by increased cerium concentrations in particulate matter due to a higher traffic volume in Madrid compared to Munich. The results obtained in this study contribute to setting reference baseline values of cerium in human breast milk and blood plasma/serum and indicate a varying cerium amount depending on the cerium environmental pollution. Possibly, the cerium content in plasma/serum could be an indicator for environmental cerium, which is not valid for breast milk.