Typing of dyslipoproteinemia

The study of fractions of lipoproteins in clinical practice is used to typify dyslipoproteinemia. Dyslipoproteinemia - deviations in the lipoprotein spectrum of the blood, manifested in a change in the content (increase, decrease, absence or disruption of the ratio) of one or more classes of lipoproteins. In 1967, a classification of types of HLP was proposed, which was approved by WHO experts and was widely used. By the end of the 1970s instead of the designation of HLP (a narrow term reflecting the increase in some class or classes of lipoproteins in the blood), the term DLP was introduced. This is due to the fact that patients with atherosclerosis and IHD often found patients who did not have an increase in the concentration of lipoproteins (that is, GLP was virtually absent), but the relationship between the content of atherogenic and anti-atherogenic lipoproteins was violated.

Classification of the main types of GLP.

Type I - hyperchylomicronemia. This type of GLP is characterized by a high content of chylomicrons, a normal or slightly elevated VLDL content, a sharp increase in the triglyceride level to 1000 mg / dl, and sometimes even higher. Type I is rarely seen, it manifests itself in childhood (hepatosplenomegaly, abdominal colic, pancreatitis). There may be xanthomas, a lipoid arc of the cornea. Atherosclerosis does not develop. The cause of this type of GLP is a genetically conditioned defect, which is based on the lack of the body's ability to produce lipoprotein lipase, which breaks down triglyceride-rich lipoprotein particles.

Type II - hyper-β-lipoproteinemia.

• Variant A. Characteristic is an elevated LDL and normal VLDL content, an increase in cholesterol, sometimes a very significant, normal triglyceride content. Concentration of HDL is often completely or relatively reduced. Variant A is manifested by IHD and MI at a relatively young age, characterized by early mortality in childhood. The essence of the genetic defect underlying the variant IIA is reduced to the deficit of LDL receptors (primarily to the deficiency of the liver receptors), which greatly complicates the elimination of LDL from the blood plasma and promotes a significant increase in the concentration of cholesterol and LDL in the blood.
• Option B. Increased LDL and VLDL, cholesterol (sometimes significantly) and TG (in most cases, moderately). This variant is manifested by IHD and MI at a relatively young age, as well as tuberculate xanthomas in childhood or in adults.

Type III - hyper-β- and hyper-pre-β-lipoproteinemia (disbetalipoproteinemia). Characteristic increase in blood VLDLP, having a high content of cholesterol and high electrophoretic mobility, that is, the presence of abnormal VLDL (flotation), the level of cholesterol and TG is elevated, the ratio of cholesterol to TG is close to 1. VAPLIS contains a lot of apo-B. Clinically, this type is characterized by the development of relatively early and heavily leaky atherosclerosis, affecting not only the vessels of the heart, but also the arteries of the lower extremities. For the diagnosis of type III HLP, it is necessary to take into account the extreme lability of lipid concentration in such patients and the ease of correcting the disturbances of lipoprotein metabolism in them under the influence of diet and medications.

Type IV - hyper-pre-β-lipoproteinemia. At type IV, an increase in the level of VLDL, a normal or reduced LDL-C content, a lack of chylomicrons, an increase in the level of TG with normal or moderately elevated cholesterol is detected in the blood. Clinical manifestations of type IV HLP are not strictly specific. There may be a lesion of both coronary and peripheral vessels. In addition to IHD, peripheral vascular lesions are typical, expressed in intermittent claudication. Xanthomas are observed less frequently than in type II. Can be a combination with diabetes and obesity. It is believed that in patients with type IV GLP lipolytic processes in adipose tissue are increased, the level of non-esterified fatty acids in the blood increases, which, in turn, stimulates the synthesis of TG and VLDL in the liver.

Type V - hyper-pre-β-lipoproteinemia and hyperchylomicronemia. At this type in the blood there is an increase in the concentration of VLDLP, the presence of chylomicrons, an increase in the cholesterol and triglycerides. Clinical this type of HLP is manifested by attacks of pancreatitis, intestinal dyspepsia, enlargement of the liver. All these manifestations occur mainly in adults, although they can also occur in children. Disorders of the cardiovascular system are rare. At the heart of the V type of HLP is the lack of lipoprotein lipase or its low activity.

Elevated blood levels of one or more LP classes may be due to various causes. GLP can occur as an independent disease (primary GLP) or may accompany diseases of internal organs (secondary GLP). The first include all family (genetic) forms of GLP, to the second - GLP, observed in a number of diseases and conditions.

Diseases and conditions accompanied by the development of secondary GLP

Diseases or conditions	Type of GLP
Alcoholism	I, IV, V
Pregnancy or administration of estrogens	IV
Hypothyroidism	IIA, IIB, IV
Diabetes	IIB, IV, V
Dysgammaglobulinemia	IIB, IV, V
Nephrotic syndrome	IIB, IV, V
OPP	IIA, IIB
Pancreatitis	IV, V
GK therapy	IV, V

GLP, identified with these diseases and conditions, can be due to the underlying pathology, not always indicating the presence of atherosclerosis. However, in this list there are a number of diseases in which, as is known from everyday clinical practice, atherosclerosis develops very often. It seems obvious that, for example, the violation of lipid metabolism in diabetes mellitus or hypothyroidism is caused by the presence of type IV GLP in these patients.

Primary HLP requires specific treatment, with secondary HLP therapy of the underlying disease often leads to normalization of lipid levels.

It should be remembered that a single determination of the content of LP in the blood (especially during an outpatient examination) may lead to incomplete or erroneous detection of the type of HLP, therefore, it is necessary to conduct repeated studies.

In addition to the listed "classical" types of GLP, DLPs that differ in very low or high HDL content, as well as their complete absence (Tanger's disease), are differentiated at the present time. However, it should be noted that the phenotypic classification of DLP is now considered obsolete, since it does not allow adequately to separate patients at risk of coronary artery disease.