Intrinsic enzymes of high-density lipoprotein

Increased levels of MMP-3, MMP-9 and MPO represent predictors of in-stent restenosis, while increased levels of ADMA, LCAT, ApoE and ApoD predict bare metal stent patency

AIMS

We sought to identify biochemical predictors that indicate susceptibility to in-stent restenosis (ISR) after coronary artery bare-metal stenting.

METHODS

A total of 111 consecutive patients with post-percutaneous coronary intervention (PCI) in-stent restenosis of a target lesion within 12 months were matched for age, sex, vessel diameter, and diabetes with 111 controls without post-PCI ISR. Plasma or serum levels of biochemical markers were measured: matrix metalloproteinases (MMP) 2, 3, 9; myeloperoxidase (MPO); asymmetric dimethylarginine (ADMA); lipoprotein (a) (Lp[a]); apolipoproteins E and D (ApoE and D); and lecitin-cholesterol acyltransferase (LCAT). Multivariable logistic regression association tests were performed.

RESULTS

Increased plasma MMP-3 (OR: 1.013; 95% CI: 1.004-1.023; P = 0.005), MMP-9 (OR: 1.014; 95% CI: 1.008-1.020; P < 0.0001) or MPO (OR: 1,003; 95% CI: 1.001-1.005; P = 0.002) was significantly associated with increased risk of ISR. Increased levels of ADMA (OR: 0.212; 95% CI: 0.054-0.827; P = 0.026), ApoE (OR: 0.924; 95% CI: 0.899-0.951; P < 0.0001), ApoD (OR: 0.919; 95% CI: 0.880-0.959; P = 0.0001), or LCAT (OR: 0.927; 95% CI: 0.902-0.952; P < 0.0001) was associated with risk reduction. No correlation was found between plasma MMP-2 or Lp (a) and ISR risk.

CONCLUSIONS

Increased levels of MMP-3, MMP-9, and MPO represent predictors of ISR after bare-metal stent implantation. In contrast, increased ADMA, LCAT, and Apo E and D indicate a decreased in-stent restenosis occurrence.

Effect of the nutritional supplement ALAnerv® on the serum PON1 activity in post-acute stroke patients

BACKGROUND

Paraoxonase-1 (PON1) is one of the HDL-associated proteins which contributes to the antioxidant properties of these lipoproteins. The aim of this pilot study was to evaluate the effect of the nutritional supplement ALAnerv® on serum PON1 activity in post-acute stroke patients undergoing rehabilitation.

METHODS

We enrolled 28 post-acute stroke patients and randomly divided them into (-) ALA or (+) ALA study groups. All the patients underwent the same rehabilitation program and received comparable standard medications. Moreover, (+) ALA patients received ALAnerv® for two weeks (2 pills/day). The serum PON1 activity was assessed on blood samples taken at the admission and at the discharge moments, respectively. We used paraoxon (paraoxonase activity, PONA), phenyl acetate (arylesterase activity, ARYLA) and dihydrocoumarin (lactonase activity, LACTA) as substrates, the latter activity being regarded as physiologically relevant. A control group of 14 apparently healthy subjects was also created.

RESULTS

In the (+) ALA group, LACTA significantly increased during the study period (17.6 ± 3.2 vs. 27.6 ± 3.5, p = 0.002). Moreover, the percentage of LACTA variation between (-) ALA and (+) ALA groups during the study was also statistically different (-11.7 ± 6.9% vs. +95.1 ± 29.7%, p < 0.0001).

CONCLUSIONS

These preliminary results suggest that ALA nerv® could contribute to the improvement of the physiologically relevant LACTA of PON1 in post-acute stroke patients, enabling this enzyme to contribute to the redox correction. Also, this study raises the question about the effect of a longer treatment period over the other enzymatic activities of serum PON1.

High-density lipoprotein and transport of cholesterol and triglyceride in blood

High-density lipoproteins (HDL) contain approximately 25% of the cholesterol and <5% of the triglyceride in the plasma of human blood. However, the dynamic exchange of lipids and lipid-binding proteins is not revealed by simply considering the mass of material at any point in time. HDL are the most complex of lipoprotein species with multiple protein constituents, which facilitate cholesterol secretion from cells, cholesterol esterification in plasma, and transfer of cholesterol to other lipoproteins and to the liver for excretion. They also play a major role in triglyceride transport by providing for activation of lipoprotein lipase, exchange of triglyceride among the lipoproteins, and removal of triglyceride rich remnants of chylomicrons and very-low-density lipoproteins after lipase action. In addition, antioxidative enzymes and phospholipid transfer proteins are important components of HDL. Many of the proteins of HDL are exchangeable with other lipoproteins, including chylomicrons and very-low-density lipoproteins. The constantly changing content of lipids and apolipoproteins in HDL particles generate a series of structures that can be analyzed by using separation techniques that depend on size or charge of the particles. Interaction of these various structures can be very different with cell surfaces depending on the size or apolipoprotein content. A series of different transport proteins preferentially exchange lipids with specific structures among the HDL but interact poorly or not at all with others. The role of these differing forms of HDL and their interactions with cells and other lipoprotein species in plasma is the subject of intense study stimulated by the potential for reducing atherogenesis. The strength of this is only partially indicated by the correlation of higher total levels of the HDL particles with reduced incidence of vascular disease in various clinical trials and epidemiological studies.