PCB126 induced toxic actions on liver energy metabolism is mediated by AhR in rats.

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor involved in the regulation of biological responses to more planar aromatic hydrocarbons, like TCDD. We previously described the sequence of events following exposure of male rats to a dioxin-like polychlorinated biphenyl (PCB) congener, 3,3',4,4',5-pentachlorobiphenyl (PCB126), that binds avidly to the AhR and causes various types of toxicity including metabolic syndrome, fatty liver, and disruption of energy homeostasis. The purpose of this study was, to investigate the role of AhR to mediate those toxic manifestations following sub-acute exposure to PCB126 and to examine possible sex differences in effects. For this goal, we created an AhR knockout (AhR-KO) model using CRISPR/Cas9. Comparison was made to the wild type (WT) male and female Holtzman Sprague Dawley rats. Rats were injected with a single IP dose of corn oil vehicle or 5 µmol/kg PCB126 in corn oil and necropsied after 28 days. PCB126 caused significant weight loss, reduced relative thymus weights, and increased relative liver weights in WT male and female rats, but not in AhR-KO rats. Similarly, significant pathologic changes were visible which included necrosis and regeneration in female rats, micro- and macro-vesicular hepatocellular vacuolation in males, and a paucity of glycogen in livers of both sexes in WT rats only. Hypoglycemia and lower IGF1, and reduced serum non-esterified fatty acids (NEFAs) were found in serum of both sexes of WT rats, low serum cholesterol levels only in the females, and no changes in AhR-KO rats. The expression of genes encoding enzymes related to xenobiotic metabolism (e.g. CYP1A1), gluconeogenesis, glycogenolysis, and fatty acid oxidation were unaffected in the AhR-KO rats following PCB126 exposure as opposed to WT rats where expression was significantly upregulated (PPARα, females only) or downregulated suggesting a disrupted energy homeostasis. Interestingly, Acox2, Hmgcs, G6Pase and Pc were affected in both sexes, the gluconeogenesis and glucose transporter genes Pck1, Glut2, Sds, and Crem only in male WT-PCB rats. These results show the essential role of the AhR in glycogenolysis, gluconeogenesis, and fatty acid oxidation, i.e. in the regulation of energy production and homeostasis, but also demonstrate a significant difference in the effects of PCB126 in males verses females, suggesting higher vulnerability of glucose homeostasis in males and more changes in fatty acid/lipid homeostasis in females. These differences in effects, which may apply to more/all AhR agonists, should be further analyzed to identify health risks to specific groups of highly exposed human populations.

Comprehensive Subchronic Inhalation Toxicity Assessment of an Indoor School Air Mixture of PCBs.

Few in vivo inhalation studies have explored the toxicity of environmentally relevant mixtures of polychlorinated biphenyls (PCBs). The manufacture of industrial PCBs was banned in 1978, but PCBs continue to be formed in industrial and consumer products. Schools represent a significant source of airborne exposures to legacy and nonlegacy PCBs, placing children at risk. To evaluate the impact of these exposures, we generated an airborne mixture of PCBs, called the School Air Mixture (SAM), to match the profile of an older school from our adolescent cohort study. Female Sprague-Dawley rats were exposed either to SAM or filtered air in nose-only exposure systems, 4 h/day for 4 weeks. Congener-specific air and tissue PCB profiles were assessed using gas chromatography with tandem mass spectrometry (GC-MS/MS). PCB exposures recapitulated the target school air profile with a similarity coefficient, cos θ of 0.83. PCB inhalation yielded µg/g ∑209 PCB levels in tissues. Neurobehavioral testing demonstrated a modest effect on spatial learning and memory in SAM-exposed rats. PCB exposure induced oxidative stress in the liver and lungs, affected the maturational stages of hematopoietic stem cells, reduced telomerase activity in bone marrow cells, and altered the gut microbiota. This is the first study to emulate PCB exposures in a school and comprehensively evaluate toxicity.

Ultrasound in Infertility Treatments.

Ultrasound (US) is very useful in diagnosing causes of infertility. Pelvic masses, mullerian anomalies, ovarian reserve, and tubal patency can all be assessed using ultrasonographic techniques. US has also proven to be a very useful aid in managing infertility treatments. In this chapter, we review the uses of US in monitoring follicular development, assessing the endometrium during treatment, and as an aid to embryo transfer during in vitro fertilization.

Postmenopausal Invasive Endometriosis Requiring Supralevator Pelvic Exenteration.

BACKGROUND: Endometriosis is rare in postmenopausal women. We report a case of invasive pelvic endometriosis in a postmenopausal woman requiring a supralevator pelvic exenteration for palliation of symptoms and for tissue diagnosis. CASE: A 65-year-old woman with a history of total abdominal hysterectomy and bilateral salpingo-oophorectomy for endometriosis at age 43 years presented with acute vaginal bleeding, hematuria, and a recently diagnosed pelvic mass. Biopsies revealed endometriosis, and she underwent supralevator pelvic exenteration with vaginectomy, end colostomy, ileal conduit, and coagulation of endometriotic implants. Pathologic examination showed invasive endometriosis and no evidence of malignancy. CONCLUSION: Endometriosis should remain on the differential diagnosis for pelvic mass in a postmenopausal woman, although suspicion for malignancy should remain high.

Obesity and reproductive function: a review of the evidence.

PURPOSE OF REVIEW: Over the last decade, the evidence linking obesity to impaired reproductive function has grown. In this article, we review this evidence and discuss the underlying pathophysiology. RECENT FINDINGS: Obese women are less likely than normal-weight women to achieve pregnancy. Female obesity adversely affects reproductive function through alterations in the hypothalamic-pituitary-ovarian axis, oocyte quality, and endometrial receptivity. It is unclear which mechanism contributes the most to subfecundity, and it is likely a cumulative process. Emerging data highlight the contribution of male obesity to impaired reproductive function and that couple obesity has synergistic adverse effects. Once pregnant, obese women are at higher risk for adverse pregnancy outcomes. Weight loss improves reproductive potential in obese patients. As obese women surpass 35 years of age, age may be more important than body mass index in determining reproductive potential. SUMMARY: Obstetrician gynecologists need to be aware of the negative impact of obesity on reproductive function so that they appropriately counsel their patients. Further work is needed to clarify the underlying pathophysiology responsible for adverse effects of obesity on reproduction so that novel treatment approaches may be developed.