[www.ncbi.nlm.nih.gov]

Unlike hyperlipidemia physicians are usually unaware of hypolipidemia, its causes and consequences.

The terms hypolipidemia, hypocholesterolemia and hypobetalipoproteinemia are used interchangeably in the literature, and refer to reduced plasma cholesterol.

Consequences of hypolipidemia


1- Effects on plasma membrane

Since about 44% of the human cell membrane is composed of lipids, they serve as a major structural component. Cell membranes are absolutely essential for the cell survival as well as for biological functions [68].

2- Intracerebral hemorrhage (ICH)

Intracranial hemorrhage accounts for approximately 10% of all strokes, and carries a significantly high morbidity and mortality as the 30-day fatality rate reaches up to 50% [72]. Several studies have demonstrated that low cholesterol is a risk factor for ICH [73–75].

3- Adrenal failure

Cholesterol molecules are the precursors for adrenal steroid hormones. The adrenal gland requires a continuous supplement of cholesterol for the biosynthesis of adrenal corticosteroids, which can be supplied by LDL receptor-mediated uptake or through local synthesis [80].

4- Sepsis

Hypocholesterolemia in healthy men is reported to be associated with significantly fewer circulating lymphocytes, total T cells, and CD8+ cells [84], thus the host immunity will be altered and the patient may be prone to infection.

5- Disease mortality

Studies suggest that lipoproteins play a role in the binding and neutralization of endotoxins [85]. Epidemiologic studies have identified a relationship between hypocholesterolemia (<130 mg/dL) and increased mortality from all causes [14].


Causes:

Hyperthyroidism

Thyroid disorders are known to affect lipid metabolism hence thyroid dysfunction may result in changes in the composition and transport of lipoproteins [21].

Critical illness

Total cholesterol levels drop at the onset of acute illness and return to normal during recovery [23, 24].

Malignancy

Several studies suggest an inverse relationship between serum cholesterol level and cancer mortality in patients with hematological and solid organ malignancies [34–39].

Malabsorption

Since dietary fats constitute the exogenous source of body lipids, undernutrition or fat malabsorption can lead to hypolipidemia.

Infection

Acute and chronic bacterial, viral, and parasitic infections all might induce hypocholesterolemia due to the chronic effect of proinflammatory cytokines on lipoprotein metabolism.

Chronic liver disease

Because hepatocytes are the most active site of lipid metabolism, hypolipidemia is frequently observed in severe chronic hepatic insufficiency [8]. A low serum cholesterol level is associated with a higher mortality rate in patients with liver cirrhosis [8, 62].

Chronic inflammation

Changes in plasma lipid levels are a well known phenomenon in the acute phase response to inflammation. Chronic inflammation also can produce hypocholesterolemia due to the chronic effect of proinflammatory cytokines on lipoprotein metabolism.



Edited 1 time(s). Last edit at 03/14/2022 01:35AM by Panchito.