10 research outputs found
Increased high-density lipoprotein cholesterol levels in mice with XX versus XY sex chromosomes
Objective—
The molecular mechanisms underlying sex differences in dyslipidemia are poorly understood. We aimed to distinguish genetic and hormonal regulators of sex differences in plasma lipid levels. Approach and Results—
We assessed the role of gonadal hormones and sex chromosome complement on lipid levels using the four core genotypes mouse model (XX females, XX males, XY females, and XY males). In gonadally intact mice fed a chow diet, lipid levels were influenced by both male–female gonadal sex and XX–XY chromosome complement. Gonadectomy of adult mice revealed that the male–female differences are dependent on acute effects of gonadal hormones. In both intact and gonadectomized animals, XX mice had higher HDL cholesterol (HDL-C) levels than XY mice, regardless of male–female sex. Feeding a cholesterol-enriched diet produced distinct patterns of sex differences in lipid levels compared with a chow diet, revealing the interaction of gonadal and chromosomal sex with diet. Notably, under all dietary and gonadal conditions, HDL-C levels were higher in mice with 2 X chromosomes compared with mice with an X and Y chromosome. By generating mice with XX, XY, and XXY chromosome complements, we determined that the presence of 2 X chromosomes, and not the absence of the Y chromosome, influences HDL-C concentration. Conclusions—
We demonstrate that having 2 X chromosomes versus an X and Y chromosome complement drives sex differences in HDL-C. It is conceivable that increased expression of genes escaping X-inactivation in XX mice regulates downstream processes to establish sexual dimorphism in plasma lipid levels
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Gastrointestinal perforation in a critically ill patient with COVID-19 pneumonia
Gastrointestinal complications in critically ill patients during the COVID-19 pandemic pose a diagnostic and treatment dilemma. We present a case of a 74-year-old male who was brought to our emergency department with worsening shortness of breath, fever, and dry cough and was found to have COVID-19 pneumonia. Early in his hospital course, he was admitted to the intensive care unit, and was found to have significant abdominal distension with large amounts of simple fluid on bedside ultrasound. Bedside paracentesis returned succus and enteric feeds, and a methylene blue test confirmed a likely gastrointestinal perforation. The patients' family refused surgical intervention and the patient underwent bedside drainage. This case represents several critical dilemmas clinicians faced during the recent surge of the COVID-19 pandemic
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Increased high-density lipoprotein cholesterol levels in mice with XX versus XY sex chromosomes.
ObjectiveThe molecular mechanisms underlying sex differences in dyslipidemia are poorly understood. We aimed to distinguish genetic and hormonal regulators of sex differences in plasma lipid levels.Approach and resultsWe assessed the role of gonadal hormones and sex chromosome complement on lipid levels using the four core genotypes mouse model (XX females, XX males, XY females, and XY males). In gonadally intact mice fed a chow diet, lipid levels were influenced by both male-female gonadal sex and XX-XY chromosome complement. Gonadectomy of adult mice revealed that the male-female differences are dependent on acute effects of gonadal hormones. In both intact and gonadectomized animals, XX mice had higher HDL cholesterol (HDL-C) levels than XY mice, regardless of male-female sex. Feeding a cholesterol-enriched diet produced distinct patterns of sex differences in lipid levels compared with a chow diet, revealing the interaction of gonadal and chromosomal sex with diet. Notably, under all dietary and gonadal conditions, HDL-C levels were higher in mice with 2 X chromosomes compared with mice with an X and Y chromosome. By generating mice with XX, XY, and XXY chromosome complements, we determined that the presence of 2 X chromosomes, and not the absence of the Y chromosome, influences HDL-C concentration.ConclusionsWe demonstrate that having 2 X chromosomes versus an X and Y chromosome complement drives sex differences in HDL-C. It is conceivable that increased expression of genes escaping X-inactivation in XX mice regulates downstream processes to establish sexual dimorphism in plasma lipid levels
Increased High-Density Lipoprotein Cholesterol Levels in Mice With XX Versus XY Sex Chromosomes
ObjectiveThe molecular mechanisms underlying sex differences in dyslipidemia are poorly understood. We aimed to distinguish genetic and hormonal regulators of sex differences in plasma lipid levels.Approach and resultsWe assessed the role of gonadal hormones and sex chromosome complement on lipid levels using the four core genotypes mouse model (XX females, XX males, XY females, and XY males). In gonadally intact mice fed a chow diet, lipid levels were influenced by both male-female gonadal sex and XX-XY chromosome complement. Gonadectomy of adult mice revealed that the male-female differences are dependent on acute effects of gonadal hormones. In both intact and gonadectomized animals, XX mice had higher HDL cholesterol (HDL-C) levels than XY mice, regardless of male-female sex. Feeding a cholesterol-enriched diet produced distinct patterns of sex differences in lipid levels compared with a chow diet, revealing the interaction of gonadal and chromosomal sex with diet. Notably, under all dietary and gonadal conditions, HDL-C levels were higher in mice with 2 X chromosomes compared with mice with an X and Y chromosome. By generating mice with XX, XY, and XXY chromosome complements, we determined that the presence of 2 X chromosomes, and not the absence of the Y chromosome, influences HDL-C concentration.ConclusionsWe demonstrate that having 2 X chromosomes versus an X and Y chromosome complement drives sex differences in HDL-C. It is conceivable that increased expression of genes escaping X-inactivation in XX mice regulates downstream processes to establish sexual dimorphism in plasma lipid levels