cholesterol

cholesterol
BorisTM · Public domain · source
Name	Cholesterol
Formula	C27H46O
Molar mass	386.65 g·mol−1
Melting point	148–150 °C
Density	1.067 g·cm−3

cholesterol Cholesterol is a sterol molecule found in animal tissues that serves as a structural component of cell membranes and a precursor for steroid hormones, bile acids, and vitamin D. Discovered in the 18th and 19th centuries during investigations by Antoine Fourcroy, Michel Eugène Chevreul, and later characterized by Friedrich Tiedemann and Heinrich Wieland, cholesterol has been central to research in biochemistry, medicine, and public health. Its roles bridge intracellular membrane dynamics, endocrine signaling, and cardiovascular disease risk, prompting extensive study across institutions such as Johns Hopkins University, Harvard Medical School, and Rockefeller University.

Structure and Properties

The molecular structure of cholesterol features a tetracyclic ring system (sterane nucleus) with a hydroxyl group at C3 and a hydrocarbon tail at C17, giving it amphipathic character noted in structural studies by Dorothy Crowfoot Hodgkin and crystallographers at Cambridge University. Physical properties such as melting point and solubility were examined in laboratories at University of Oxford and University of Göttingen during the 20th century. Cholesterol's rigid planar rings influence membrane order, a concept explored in biophysical work by groups at Max Planck Society and CNRS, and the molecule participates in lipid raft formation studied at Massachusetts Institute of Technology.

Biosynthesis and Metabolism

Biosynthesis of cholesterol proceeds via the mevalonate pathway, with key enzymatic steps catalyzed by HMG-CoA reductase—a target of statins developed by researchers at Merck and AstraZeneca after basic work from Akira Endo—and squalene epoxidase leading to lanosterol and subsequent conversion to cholesterol, as mapped by metabolic studies at University of California, San Francisco. Hepatic synthesis and extrahepatic production are regulated by transcription factors such as SREBP proteins identified through molecular genetics at Cold Spring Harbor Laboratory. Catabolism occurs via conversion to bile acids in the liver through enzymes characterized in teams at Karolinska Institutet and University of Tokyo, and enterohepatic circulation was elucidated in clinical research centers including Mayo Clinic. Transport in plasma utilizes lipoprotein particles—very-low-density, low-density, and high-density lipoproteins—whose particles and apolipoproteins (e.g., ApoB, ApoA-I) were characterized by investigators at Washington University School of Medicine and Rockefeller University.

Physiological Roles

Cholesterol is essential for membrane fluidity and permeability in cells examined at Salk Institute and Weill Cornell Medicine. It serves as the precursor for steroid hormones synthesized in endocrine organs such as the adrenal cortex and gonads, producing cortisol, aldosterone, testosterone, and estradiol—hormones studied by endocrinologists at Cleveland Clinic and University College London. Cholesterol is also the substrate for vitamin D3 synthesis in the skin upon ultraviolet B exposure, a photobiology focus at Karolinska Institutet and Imperial College London. In the liver, cholesterol conversion to bile acids facilitates lipid absorption in the intestine, research pursued at Children's Hospital Boston and Stanford University.

Clinical Significance and Disorders

Elevated plasma low-density lipoprotein cholesterol levels are associated with atherosclerosis and coronary artery disease, findings from landmark trials at Framingham Heart Study and randomized trials by investigators at National Institutes of Health and British Heart Foundation. Familial hypercholesterolemia, caused by mutations in genes such as LDLR, was described by clinicians at St Bartholomew's Hospital and geneticists at University of Amsterdam. Cholesterol metabolism defects underlie conditions including Smith–Lemli–Opitz syndrome characterized by work at Yale University and Niemann–Pick disease researched at Hopkins. Therapeutic interventions include HMG-CoA reductase inhibitors (statins) developed in pharmaceutical programs at Merck and tested in large outcomes trials by consortia including International Atherosclerosis Society investigators; bile acid sequestrants and PCSK9 inhibitors emerged from translational research at Amgen and clinical trials at Cleveland Clinic.

Measurement, Guidelines, and Management

Clinical measurement of plasma cholesterol and lipoprotein fractions is performed using assays standardized by organizations like the World Health Organization and clinical laboratories at Mayo Clinic; guidelines for risk assessment are issued by bodies such as the American College of Cardiology and European Society of Cardiology. Management strategies combine lifestyle interventions promoted by public health agencies including Centers for Disease Control and Prevention and pharmacotherapy guided by trials from University of Oxford and multicenter networks led by NIH. Ongoing research into lipid-lowering therapies, vaccine approaches to atherosclerosis, and precision medicine involves collaborations among universities such as Johns Hopkins University, biotech firms like Amgen, and regulatory authorities including the Food and Drug Administration.

Category:Lipids