Treatment for cardiovascular and related diseases

Abstract

A method for the removal of cholesterol, triglycerides and other lipids from animal plasma, serum or other suitable blood fractions, as a discontinuous flow system, the method comprising withdrawing blood from a subject, separating the required fraction from the blood and mixing with a solvent mixture which extracts the lipids from the fraction, after which the delipidated fraction is recombined with the blood cells and returned to the subject, wherein the solvent extraction step is carried out separately and remote from the subject. The delipidated fraction is washed with a second solvent before being recombined with the blood cells. To ensure that the delipidated fraction is free from all extraction solvent, the fraction is mixed with an absorbent specific for the solvent that is being removed. The preferred absorbent is a macroporous polymeric bead contained in the pores of a sintered glass or plastic sphere, the being capable of absorbing organic molecules from an aqueous solution. By treating the plasma, serum or other suitable blood fraction of a patient by these methods, the blood rheology of a patient with impaired blood circulation can be improved. Further, a rapid regression of coronary atherosclerosis occurs.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is a U.S. National Phase Application filed under 35 U.S.C. § 371 based on International Application No. PCT / AU95 / 00875, having an International Filing Date of Dec. 22, 1995.TECHNICAL FIELD[0002]THIS INVENTION relates to plasma or serum delipidation in animals (which term shall indicate humans), to a treatment for cardiovascular disease and to removal of excess fat from the animals. In particular, it is directed to the removal of cholesterol, triglycerides and other lipids, and fat soluble toxins—for example, insecticides—from the blood plasma or serum of such animals.BACKGROUND ART[0003]Cardiovascular diseases are responsible for a significant number of deaths in most industrialised countries.[0004]One such disease is atherosclerosis which is characterised by local fatty thickening in the inner aspects of large vessels supplying blood to the heart, brain and other vital organs. These lesions obstruct the lumen of the vesse...

AI Technical Summary

Benefits of technology

[0028]It is an object of the present invention to overcome, or at least ameliorate, the above-mentioned disadvantages in the provision of a method for delipidating not only plasma but also serum and other blood fractions which substantially reduces the exposure of the patient to the potentially hazardous solvents used, which also can effectively remove all traces of solvent(s) used in that delipidation, and which significantly reduces the contact time between the patient and the actual delipidation process.

[0029]It is a further object to provide a method whereby advantageous changes to the blood rheology of the originally impaired blood circulation of the patient can be achieved.

[0030]It is yet another object to provide a method whereby a patient's Plasma or serum can be treated remote from that patient, thus allowing either autologous or non-autologous plasma or serum to be returned to the patient at a later date.

[0032]Preferably, as part of the solvent extraction step, beads are used when mixing the blood fractions with the solvent. More preferably, the beads have a density substantially mid-way between the density of the fraction and the density of the solvent mixture. This ensures efficient mixing with a large surface area, increasing the efficiency of the extraction and also serving as a good separator of the plasma from the solvent when centrifugation is used to isolate the phases after extraction.

[0039]However, as another aspect of the present invention, efficient removal of the extraction solvent can be achieved by mixing the delipidated fraction with an absorbent specific for the solvent that is being removed.

Problems solved by technology

Cardiovascular diseases are responsible for a significant number of deaths in most industrialised countries.

These lesions obstruct the lumen of the vessel and result in ischaemia of the tissue supplied by the vessel.

Prolonged or sudden ischaemia may result in a clinical heart attack or stroke from which the patient may or may not recover.

However, the use of diet as a primary mode of therapy requires a major effort on the part of physicians, nutritionists, dieticians and other health professionals.

However, there is no direct evidence that any cholesterol-lowering drug can be safely administered over an extended period.

Many drugs are effective in reducing blood lipids, but none work in all types of hyperlipidaemia and they all have undesirable side effects.

There is no conclusive evidence that hypolipidaemic drugs can cause regression of atherosclerosis.

Thus, despite progress in achieving the lowering of plasma cholesterol to prevent heart disease by diet, drug therapies, surgical revascularization procedures and angioplasty, atherosclerosis remains the major cause of death in Western Countries.

This treatment can result in complications due to the possible introduction of foreign proteins and transmission of infectious diseases.

Therefore, removal of HDL is not advantageous.

Furthermore, LDL removal may be counter productive as, low blood LDL levels may result in increased cellular cholesterol synthesis.

While cholesterol aphaeresis has overcome the shortcomings of dietary and / or drug treatments and other aphaeretic techniques, existing apparatus for cholesterol aphaeresis does not provide a sufficiently rapid and safe process.

Unfortunately, practice has established that the cholesterol aphaeresis systems described above still suffer from a number of disadvantages.

The first disadvantage is the explosive nature of the solvents used to delipidate this plasma.

This hazard is clearly present for the duration of the delipidation process which usually runs for several hours.

The second disadvantage is that, in the prior continuous systems, a reliable procedure is not available to remove totally all of the solvents used in the delipidation before the treated plasma is returned to the patient.

It is not possible to provide sequential multi-washes in a continuous system because the patient would have to supply an unacceptable volume of blood to maintain each stage of the system overall and the patient would also be subjected to an increased hazard factor from the prolonged exposure to the solvents.

Certainly, external contact with this solvent is known to cause irritation of mucous membranes, contact dermatitis, headaches, dizziness and drowsiness.

A third disadvantage is that the continuous systems described above are not suitable for the delipidation of serum.

Yet a fourth disadvantage is that delipidation in a continuous system is undertaken over several hours.