Improving Effects of Epigallocatechin-3-Gallate on Hemorheological Abnormalities of Aging Guinea Pigs

Impaired Hemorheological Parameters and Increased Carotid Intima-Media Thickness in Children with Subclinical Hypothyroidism

BACKGROUND

Subclinical hypothyroidism (SH) is defined as elevated serum thyroid-stimulating hormone (TSH) concentration associated with normal serum-free thyroxine levels. Effects of hypothyroidism on hemorheology had widely attracted the attention of researchers during the last decade.

OBJECTIVE

The purpose of this study is to determine alterations in hemorheological parameters and carotid intima-media thickness (CIMT) in children with SH.

METHODS

Fifty-three SH children and 31 healthy controls were enrolled. Erythrocyte deformability and aggregation were determined by an ektacytometer and plasma viscosity (PV) by a cone-plate rotational viscometer. CIMT was evaluated sonographically.

RESULTS

Erythrocyte deformability of the SH group measured at 0.53 and 1.69-30 Pa was lower than that of the control group. The erythrocyte aggregation index, aggregation half time and PV were not different between the groups. However, the aggregation amplitude and mean corpuscular hemoglobin concentration were significantly higher in SH compared to the control group. There was a negative correlation between TSH and deformability values measured at 5.33-30.0 Pa. CIMT in patients with SH was significantly higher than in the control group (p = 0.001; SH = 0.48 ± 0.04 mm, control group = 0.43 ± 0.03 mm).

CONCLUSION

Impaired hemorheology and increased CIMT are well-known risk factors for developing cardiovascular pathologies. The results of the current study suggest the treatment of children with SH in order to avoid early circulatory problems.

Hemorheological parameters and their correlations in OXYS rats: a new model of hyperviscosity syndrome

Rheohaemapheresis aims to normalize major rheological parameters and is used to treat patients with dry age-related macular degeneration (AMD). While effective, this approach is invasive and requires specially trained personnel. Therefore, the search for novel effective compounds with hemorheological properties that can be taken orally to treat AMD is justified. The use of a robust rodent model of AMD with high blood viscosity is crucial to test the efficacy of potential hemorheological drugs to treat this disease. The objective of this study was to investigate whether OXYS rats, generally used as an animal model of AMD, have hyperviscosity syndrome. The results of this study show that blood viscosity in OXYS rats at low (3-10 s -1) and high (45-300 s -1) shear rates were 14-20% and 7-10% higher than in Wistar rats, while hematocrit and plasma viscosity were not different. Red blood cells (RBCs) in OXYS rats were more prone to aggregation as shown by 39% shorter half-time than in Wistar rats. RBCs were also more rigid in OXYS than in Wistar rats as shown by 21-33% lower index of elongation at the shear stress of 1-7 Pa. These data indicate that OXYS rats have hyperviscosity syndrome as the result of abnormal RBC deformability and aggregation. We propose to use OXYS rats as an animal model for preclinical studies to test compounds with hemorheological properties aimed to treat AMD.

The Protective Effect of Epigallocatechin-3-gallate on Paraquat-induced Haemolysis

Epigallocatechin-3-gallate (EGCG) is a major ingredient present in green tea, which has a high antioxidant activity. In this study, the effect of EGCG was investigated on paraquat-induced haemolysis of erythrocyte membrane. Erythrocytes were incubated in 0.03, 0.3, 3.0 and 30 mg/mL EGCG, respectively and exposed to 30 mg/mL of paraquat for 10 minutes. The effect of paraquat was determined by an analysis of the osmotic fragility of the erythrocytes. The results showed that EGCG (30 mg/mL) significantly (p < 0.05) reduced the haemolysis of erythrocytes exposed to paraquat (5.0 mg/mL). This suggests that EGCG may have a protective effect on paraquat-induced erythrocyte membrane haemolysis and that consumption of green tea, with high EGCG concentration, could ameliorate the deleterious effect of paraquat toxicity on the haemolysis of erythrocyte membrane.

Association between green tea intake and coronary artery disease in a Chinese population

BACKGROUND

There is still conflicting evidence that green tea may protect against coronary atherosclerosis therefore the present study investigated the association between green tea consumption and arteriographically determined coronary atherosclerosis in a Chinese population.

METHODS AND RESULTS

The study population consisted of 520 consecutive patients (379 men and 141 women) who underwent coronary arteriography for the first time. Patients were divided into 2 groups (Non-coronary artery disease [CAD] and CAD groups) according to the results of coronary arteriography. After adjusting the established and potential confounders, green tea consumption was associated with a reduced risk of CAD in male patients, with an adjusted odds ratio (OR) of 0.62 (95% confidence interval, 0.38-1.01) compared with those who did not drink green tea. Compared to non-tea drinkers, the adjusted ORs were 1.09 (0.61-1.96) in male patients consuming less than 125 g of dried green tea leaves per month, 0.36 (0.19-0.71) for 125-249 g per month and 0.36 (0.17-0.73) for > or =250 g per month, with a statistically significant test for trend (P<0.001). Similar dose-response relationships were also observed for frequency, duration, concentration and starting age of green tea drinking in male patients. In female patients, no inverse association was found between green tea consumption and CAD.

CONCLUSIONS

Green tea consumption can protect against the development of coronary atherosclerosis in Chinese male patients.