Cholesterol/Hypercholesterolemia/Hyperlipidemia
Charles Theisler in Adjuvant Medical Care, 2023
Abnormally high amounts of any or all fats in the blood, whether cholesterol (hypercholesterolemia), triglycerides (hypertriglyceridemia), or related compounds, is hyperlipidemia. Cholesterol is a waxy, fat-like substance produced by the liver and found in cell walls and nerves. Both cholesterol and its derivatives are important parts of healthy cell membranes, bile acids, and hormones and allow the body to produce vitamin D. High cholesterol has no signs or symptoms, but excess cholesterol forms fatty deposits in the walls of the arteries. Over time, as the cholesterol accumulates, it causes atherosclerotic plaques to form, which thicken and harden the artery walls. This is referred to as atherosclerosis. High serum cholesterol and its subtypes, especially low-density lipoproteins (LDLs), which transport cholesterol to the tissues increase the risk for developing atherosclerosis, coronary artery disease, heart attack, and ischemic stroke.
Pathophysiology of Diabetes
Jahangir Moini, Matthew Adams, Anthony LoGalbo in Complications of Diabetes Mellitus, 2022
Diabetes mellitus is a disease state that is related to the availability and effectiveness of insulin in the body. Type 1 diabetes involves a total lack of insulin, resulting from autoimmune destruction of pancreatic beta cells. Autoimmune destruction occurs in genetically susceptible people, triggered by environmental factors and progressing over months to years. This eventually results in symptomatic hyperglycemia and the classic signs and symptoms of the disease. Type 2 diabetes is characterized by the body’s peripheral tissues being resistant to the effects of insulin. Both classifications of diabetes lack the signaling effect of insulin, while glucagon and other metabolic signals are of normal or high levels. Diabetes mellitus is due to an imbalance in carbohydrate metabolism and resultant effects upon other metabolic pathways. Insulin resistance causes the body to react, even though it is present at extreme levels. This form differs from type 1 diabetes in that the liver can still manufacture glycogen. Lipolysis is controlled due to the presence of insulin. Plasma lipoproteins are usually elevated, often due to poor nutrition and obesity. Pancreatic failure leads to decreased insulin production and secretion. The brain continually requires glucose in order to function normally. Hypoglycemia is often caused by drugs used to treat diabetes mellitus, which include insulin and the oral antihyperglycemic medications.
Components of Nutrition
Christopher Cumo in Ancestral Diets and Nutrition, 2020
Among fats, attention focuses on cholesterol, mentioned earlier, as contributor to heart disease. In this context, medical practitioners distinguish between good and bad cholesterol. This language causes confusion because “good cholesterol” is more than cholesterol—also having protein, triglycerides, and phospholipids (a lipid with phosphorus)—and is known as high-density lipoproteins (HDL).56 Doctors praise HDL for removing excess cholesterol from the blood whereas low-density lipoproteins (LDL)—having different ratios of the same components—are deemed bad because they carry cholesterol to cells. Cells depend on LDL for it, though problems arise when LDL bring too much. Criticisms of cholesterol should not discount its role in manufacturing cell membranes, acids that help digest food, vitamin D from sunlight, and five types of steroid hormones: progestins, glucocorticoids, mineralocorticoids, estrogens, and androgens, all of which the body requires.
Human ovarian granulosa cells use clathrin-mediated endocytosis for LDL uptake: immunocytochemical and electron microscopic study
Published in Ultrastructural Pathology, 2023
Aynur Abdulova, Merjem Purelku, Hakan Sahin, Gamze Tanrıverdi
Steroidogenesis is a complex process between multiple enzymes and substrates by which cholesterol is converted into steroid hormones. Cholesterol is stored in lipid droplets (LDs) as cholesterol esters (CEs) within the steroidogenic tissue. The cholesterol that is required for steroidogenesis which is being initiated in response to a hormonal stimulus is provided by the mobilization of these stored CEs within the cells.3 There are two different forms of cholesterol which are known as high-density lipoprotein (HDL) and low-density lipoprotein (LDL). Studies are focused on the fact that granulosa cells use the LDL-receptor (LDLR)-mediated endocytic pathway for steroid biosynthesis. LDLR is an important protein that functions to mediate the uptake of LDL cholesterol, which is a specific substrate for steroid hormone production.3–5 Many different endocytic pathways have been described in eukaryotic cells, but the main pathway for LDL transport has been reported to be the clathrin-mediated endocytosis pathway.6,7 However, no study that clarifies LDL internalization in human granulosa cells and whether the clathrin-mediated endocytic pathway is functional in this process has yet been published.
Focus on cardiometabolic risk factors
Published in Acta Cardiologica, 2023
Assessment of cardiovascular risk using established risk scores such as European Society of Cardiology (ESC) SCORE2 or PROCAM insufficiently emphasise the role of genetic factors. In their study, Krohn et al. showed that both scores failed to adequately discriminate between stable and unstable disease patients with ACS, highlighting the need for optimised risk prediction models involving emerging risk modifiers such as genetic factors or inflammation. Conversely, these authors showed that commercially available assays for genetic polymorphisms may offer useful information on a person’s hereditary risk for CVD, which could help direct future primary and/or secondary preventative therapy for coronary artery disease [14,15]. High plasma concentrations of lipoprotein (a) are associated with an increased cardiovascular risk. Current guidelines recommend the measurement of only a single Lp(a) in an individual’s lifetime under specific circumstances to improve cardiovascular risk prediction. In their study, Deconinck et al. examined the number of false positives and negatives missed through only a single measurement of Lp(a). The authors reported that the determination of Lp(a) was reproducible and that a single measurement was sufficient to assess whether a patient exceeded cut-off values [16] (Figure 2).
Metformin ameliorates ROS-p53-collagen axis of fibrosis and dyslipidemia in type 2 diabetes mellitus-induced left ventricular injury
Published in Archives of Physiology and Biochemistry, 2023
Bahjat Al-Ani, Norah M. Alzamil, Peter W. Hewett, Fahaid Al-Hashem, Ismaeel Bin-Jaliah, Abdullah S. Shatoor, Samaa S. Kamar, Noha S. Abdel Latif, Mohamed A. Haidara, Amal F. Dawood
Diabetes upsurges heart disease and stroke risks, affecting millions worldwide, and an estimated four out of five diabetic patients were subjected to death due to cardiovascular complications (Laakso 2010, Danaei et al.2011). Dyslipidemia is found to be a risk factor in developing and progressing coronary heart disease (Welty 2001), hypertension (Otsuka et al.2016), as well as vascular injury (Rafieian-Kopaei et al.2014). In addition, elevated blood levels regarding low-density lipoprotein (LDL) as well as high-density lipoprotein (HDL) low levels exhibited a correlation to myocardial infarction and stroke (Yaghi and Elkind 2015, Ference et al.2017). Abdominal obesity as metabolic syndrome criterion also referred to as pre-diabetes, represents abnormalities cluster characterised by resisting insulin, hypertension, oxidative stress, inflammation in addition to dyslipidemia. This condition has effect on 25% of population (mainly those who are >50 years old) and holds elevated risk towards cardiovascular disease, T2DM, disease of non-alcoholic fatty liver in addition to cancer (Eckel et al.2005, Grattagliano et al.2008, Kopelman 2000).
Related Knowledge Centers
- Biochemistry
- Extracellular Fluid
- Phospholipid
- Lipid
- Blood Plasma
- Apolipoprotein
- Fat
- Triglyceride
- Cholesterol
- High-Density Lipoprotein