Chronic cypermethrin exposure alters mouse embryonic stem cell growth kinetics, induces Phase II detoxification response and affects pluripotency and differentiation gene expression

The impact of endocrine-disrupting chemicals on stem cells: Mechanisms and implications for human health

Endocrine-disrupting chemicals (EDCs) are compounds, either natural or man-made, that interfere with the normal functioning of the endocrine system. There is increasing evidence that exposure to EDCs can have profound adverse effects on reproduction, metabolic disorders, neurological alterations, and increased risk of hormone-dependent cancer. Stem cells (SCs) are integral to these pathological processes, and it is therefore crucial to understand how EDCs may influence SC functionality. This review examines the literature on different types of EDCs and their effects on various types of SCs, including embryonic, adult, and cancer SCs. Possible molecular mechanisms through which EDCs may influence the phenotype of SCs are also evaluated. Finally, the possible implications of these effects on human health are discussed. The available literature demonstrates that EDCs can influence the biology of SCs in a variety of ways, including by altering hormonal pathways, DNA damage, epigenetic changes, reactive oxygen species production and alterations in the gene expression patterns. These disruptions may lead to a variety of cell fates and diseases later in adulthood including increased risk of endocrine disorders, obesity, infertility, reproductive abnormalities, and cancer. Therefore, the review emphasizes the importance of raising broader awareness regarding the intricate impact of EDCs on human health.

Cytochrome P450-derived fatty acid epoxides and diols in angiogenesis and stem cell biology

Cytochrome P450 (CYP) enzymes are frequently referred to as the third pathway for the metabolism of arachidonic acid. While it is true that these enzymes generate arachidonic acid epoxides i.e. the epoxyeicosatrienoic acids (EETs), they are able to accept a wealth of ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) to generate a large range of regio- and stereo-isomers with distinct biochemical properties and physiological actions. Probably the best studied are the EETs which have well documented effects on vascular reactivity and angiogenesis. CYP enzymes can also participate in crosstalk with other PUFA pathways and metabolize prostaglandin G₂ and H₂, which are the precursors of effector prostaglandins, to affect macrophage function and lymphangiogenesis. The activity of the PUFA epoxides is thought to be kept in check by the activity of epoxide hydrolases. However, rather than being inactive, the diols generated have been shown to regulate neutrophil activation, stem and progenitor cell proliferation and Notch signaling in addition to acting as exercise-induced lipokines. Excessive production of PUFA diols has also been implicated in pathologies such as severe respiratory distress syndromes, including COVID-19, and diabetic retinopathy. This review highlights some of the recent findings related to this pathway that affect angiogenesis and stem cell biology.

The endangered African Great Ape: Pesticide residues in soil and plants consumed by Mountain Gorillas (Gorilla beringei) in Bwindi Impenetrable National Park, East Africa

Bwindi Impenetrable National Park situated southwest of Uganda is a biodiversity hotspot that is home to about half of the world's endangered mountain gorilla (Gorilla beringei). Given its ecological significance and mounting pressures from agricultural activities such as tea growing, continuous monitoring of the levels of chemical toxins like pesticides in the park and surrounding areas is needed for effective conservation strategies. Furthermore, persistent organochlorine pesticides (OCPs) like DDT were used in agricultural gardens and indoor spraying in Kanungu district between the 1950s and 80s. The focus of this study was to explore the possible exposure of mountain gorillas to OCPs and cypermethrin used by the farmers in the areas near the park. Data from our interviews revealed that glyphosate is the most widely used pesticide by the farmers in areas surrounding the park, followed by cypermethrin, and mancozeb. Samples of leaves from plants consumed by mountain gorillas along the forest edges of the park and surficial soils (15-20 cm depths) were collected from three sites (Ruhija, Nkuringo and Buhoma) and analysed for the presence of cypermethrin and OCPs residues. Concentrations of total (∑) DDTs and ∑endosulfans were up to 0.34 and 9.89 mg/kg dry weight (d.w), respectively in soil samples. Concentrations of ∑DDTs and ∑endosulfans in samples of leaves ranged from 0.67 to 1.38 mg/kg d.w (mean = 1.07 mg/kg d.w) and 0.9 to 2.71 mg/kg d.w (mean = 1.68 mg/kg d.w), respectively. Mean concentration of ∑DDTs in leaves exceeded the European pharmacopeia and United States pharmacopeia recommended maximum residue limit values for DDTs in medicinal plants (1.0 mg/kg). In addition, calculated hazard indices for silverbacks (36.35), females (57.54) and juveniles (77.04) suggested potential health risks to the mountain gorillas. o,p'-DDT/p,p'-DDT ratios (0.5-0.63) in samples of leaves confirmed recent input of dicofol-DDT type in Bwindi rainforest.

Effect of oral administration of a mixture of pyrethroids at doses relevant to human exposure on the general and male reproductive physiology in the rat

Studies on the effects of unintentional intake of pyrethroid pesticides that are akin to actual human exposure settings are very rare. Such an exposure is primarily by consuming the food products as routine diet that contain residual levels of pyrethroids. In this study, rats were orally administered for 15 months with a mixture of pyrethroids at a dose that is one-fifth (high dose; HD) or one-twenty fifth (low dose; LD) of the residual levels commonly present in the average amount of rice and vegetables consumed by Indian population. Lipid profile, kidney and liver function were assessed. Lipid peroxidation, nitric oxide, antioxidant enzyme activities and histopathological changes were analyzed in the liver, lung, kidney, pancreas, testes, caput, cauda and prostate. The effect on the male reproductive system as a function of sperm count, enzyme activity of 3β-HSD and 17β-HSD and the expression profile of genes involved in spermatogenesis, steroidogenesis, genetic reprogramming and apoptosis of male gametes were evaluated. Significant increase in the relative organ weight, perturbations in the activities of antioxidant enzymes, lipid profile and liver function were observed in both LD and HD groups. Damage to the anatomical architecture was evident in all the tissues due to pyrethroid toxicity. Exposure to LD and HD of pyrethroid mixture resulted in decreased sperm count, activities of 3β-HSD and 17β-HSD, impaired capacitation and acrosome reaction and perturbations in the expression of genes that govern male gamete production. Results of our study indicate that exposure to pyrethroids for longer durations even at doses that are far below the residual levels present in the food consumed will result in severe damage to general physiological processes as well as reproductive function.

Twenty years of histochemistry in the third millennium, browsing the scientific literature

Over the last twenty years, about 240,000 articles where histochemical techniques were used have been published in indexed journals, and their yearly number has progressively increased. The histochemical approach was selected by researchers with very different scientific interests, as the journals in which these articles were published fall within 140 subject categories. The relative proportion of articles in some of these journal categories did change over the years, and browsing the table of contents of the European Journal of Histochemistry, as an example of a strictly histochemical journal, it appeared that in recent years histochemical techniques were preferentially used to mechanistically investigate natural or experimentally induced dynamic processes, with reduced attention to purely descriptive works. It may be foreseen that, in the future, histochemistry will be increasingly focused on studying the molecular pathways responsible for cell differentiation, the maintenance or loss of the differentiated state, and tissue regeneration.