Potential effects of polychlorinated biphenyls (PCBs) and selected organochlorine pesticides (OCPs) on immune cells and blood biochemistry measures: a cross-sectional assessment of the NHANES 2003-2004 data

Effects of PCBs and PBDEs on thyroid hormone, lymphocyte proliferation, hematology and kidney injury markers in residents of an e-waste dismantling area in Zhejiang, China

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are two typical categories of contaminants released from e-waste dismantling environments. In China, the body burdens of PCBs and PBDEs are associated with abnormal thyroid hormones in populations from e-waste dismantling sites, but the results are limited and contradictory. In this study, we measured the serum levels of PCBs and PBDEs and the thyroid hormone free triiodothyronine (FT3), free thyroxine (FT4) and thyroid-stimulating hormone (TSH) in 40 residents in an e-waste dismantling area and in 15 residents in a control area. Additionally, we also measured some lymphocyte proliferation indexes, hematologic parameters and kidney injury markers, including white blood cells, neutrophils, monocytes, lymphocytes, hemoglobin, platelets, serum creatinine and beta 2-microglobulin (β2-MG). The results indicated that the mean level of ΣPCBs in the exposure group was significantly higher than that in the control group (964.39 and 67.98 ng g(-1), p<0.0001), but the mean level of ΣPBDEs in the exposure group was not significantly higher than that in the controls (139.32 vs. 75.74 ng g(-1), p>0.05). We determined that serum levels of FT3, FT4, monocytes and lymphocytes were significantly lower, whereas the levels of neutrophils, hemoglobin, platelets and serum creatinine were significantly higher in the exposed group (p<0.05). The mean level of ΣPCBs was negatively correlated with levels of FT3, FT4, monocytes and lymphocytes (p<0.05) and positively correlated with levels of neutrophils, hemoglobin, serum creatinine and β2-MG (p<0.05). Additionally, the mean level of ΣPBDEs was positively correlated with levels of white blood cells, hemoglobin and platelets (p<0.05). Our data suggest that exposure to an e-waste dismantling environment may increase the body burdens of PCBs and the specific PBDEs congeners in native residents and that the contaminants released from e-waste may contribute to abnormal changes in body levels of thyroid hormone, hematology and kidney injury markers.

Identification of a novel lytic peptide for the treatment of solid tumours

Originally known as host defence peptides for their substantial bacteriotoxic effects, many cationic antimicrobial peptides also exhibit a potent cytotoxic activity against cancer cells. Their mode of action is characterized mostly by electrostatic interactions with the plasma membrane, leading to membrane disruption and rapid necrotic cell death.

In this work, we have designed a novel cationic peptide of 27 amino acids (Cypep-1), which shows efficacy against a number of cancer cell types, both in vitro and in vivo, while normal human fibroblasts were significantly less affected. Surface plasmon resonance experiments as well as liposome leakage assays monitored by fluorescence spectroscopy revealed a substantial binding affinity of Cypep-1 to negatively charged liposomes and induced significant leakage of liposome content after exposure to the peptide. The observed membranolytic effect of Cypep-1 was confirmed by scanning electron microscopy (SEM) as well as by time-lapse confocal microscopy. Pharmacokinetic profiling of Cypep-1 in rats showed a short plasma half-life after i.v. injection, followed mainly by retention in the liver, spleen and kidneys. Extremely low concentrations within the organs of the central nervous system indicated that Cypep-1 did not pass the blood-brain-barrier.

Local treatment of 4T1 murine mammary carcinoma allografts by means of a single local bolus injection of Cypep-1 led to a significant reduction of tumour growth in the following weeks and prolonged survival. Detailed histological analysis of the treated tumours revealed large areas of necrosis.

In sum, our findings show that the novel cationic peptide Cypep-1 displays a strong cytolytic activity against cancer cells both in vitro and in vivo and thus holds a substantial therapeutic potential.