Biomedical subjects

Gerhard Rechkemmer

Publications and source records attributed to Gerhard Rechkemmer.

23 records · Page 2Linked to original sources

PubMed2003

Fruit juice consumption modulates antioxidative status, immune status and DNA damage.

Polyphenolic compounds exert a variety of physiological effects in vitro including antioxidative, immunomodulatory and antigenotoxic effects. In a randomized crossover study in healthy men on a low-polyphenol diet, we determined the effects of 2 polyphenol-rich juices (330 ml/d) supplemented for 2 weeks on bioavailability of polyphenols, markers of antioxidative and immune status, and reduction of DNA damage. Juices provided 236 mg (A) and 226 mg (B) polyphenols with cyanidin glycosides (A) and epigallocatechin gallate (B) as major polyphenolic ingredients. There was no accumulation of plasma polyphenols after two weeks of juice supplementation. In contrast, plasma malondialdehyde decreased with time during juice interventions. Moreover, juice consumption also increased lymphocyte proliferative responsiveness, with no difference between the two juices. Interleukin-2 secretion by activated lymphocytes and the lytic activity of natural killer cells were significantly increased by both juices. Juice intervention had no effect on single DNA strand breaks, but significantly reduced oxidative DNA damage in lymphocytes. A time-delay was observed between the intake of fruit juice and the reduction of oxidative DNA damage and the increase in interleukin-2 secretion. We conclude that consumption of either juice enhanced antioxidant status, reduced oxidative DNA damage and stimulated immune cell functions. However, fruit juice consumption for 2 weeks did not result in elevated plasma polyphenols in subjects after overnight fasting. Further studies should focus on the time-delay between juice intake and changes in measured physiological functions, as well as on active polyphenolic metabolites mediating the observed effects.

Adult↗

PubMed2003

Supplementation of a low-carotenoid diet with tomato or carrot juice modulates immune functions in healthy men.

BACKGROUND: Beta-carotene has been shown to enhance immune functions in humans. Whether vegetables rich in carotenoids, such as beta-carotene or lycopene, modulate immune functions in healthy humans is presently not known. The objective of this study was to investigate the effects of a low-carotenoid diet supplemented with either tomato (providing high amounts of lycopene) or carrot juice (providing high amounts of alpha- and beta-carotene) on immune functions in healthy men. METHOD: In a blinded, randomized, cross-over study, male subjects on a low-carotenoid diet consumed 330 ml/day of either tomato juice (37.0 mg/day lycopene) or carrot juice (27.1 mg/day beta-carotene and 13.1 mg/day alpha-carotene) for 2 weeks with a 2-week depletion period after juice intervention. Immune status was assessed by measuring lytic activity of natural killer (NK) cells, secretion of cytokines (IL-2, IL-4, TNFalpha), and proliferation by activated peripheral blood mononuclear cells. RESULTS: Juice consumption resulted in relatively fast responses in plasma carotenoid concentrations (p < 0.0002) which were not accompanied by concomitant changes in immune functions. For IL-2, NK cell cytotoxicity, and lymphocyte proliferation, maximum responses were observed during depletion periods. The highest production rate was measured only for TNFalpha at the end of the first intervention period. Juice intervention did not modulate the secretion of IL-4. CONCLUSIONS: Increased plasma carotenoid concentrations after vegetable juice consumption are accompanied by a time-delayed modulation of immune functions in healthy men consuming a low-carotenoid diet.

Adult↗

PubMed2002

Acute intake of moderate amounts of red wine or alcohol has no effect on the immune system of healthy men.

BACKGROUND: A recent prospective cohort study revealed that moderate wine consumption but not consumption of other alcoholic beverages is associated with a decreased risk of common cold. In contrast, wine constituents such as ethanol and polyphenols are known to suppress immunity. AIM OF THE STUDY: We investigated whether acute intake of a moderate amount of alcohol modulates immune functions in healthy men and whether polyphenols in red wine with antioxidative and immunomodulatory potential induce changes in immune functions that differ from those induced by the consumption of the 12 % ethanol. METHODS: Six healthy males with moderate alcohol consumption patterns randomly consumed a single dose of 500 ml of red wine (12 % ethanol), a 12 % ethanol dilution, dealcoholized red wine, and red grape juice, respectively. The following immune functions were measured before beverage consumption and 1, 3, and 24 h later: phagocytic activity and intensity of neutrophils and monocytes, production of tumor necrosis factor-alpha, interleukin-2, and interleukin-4, lymphocyte proliferation, and lytic activity of natural killer cells. RESULTS: Acute consumption of a moderate amount of red wine and of a 12 % ethanol solution had no effect on immune functions in men. Acute consumption of polyphenol-rich beverages (dealcoholized red wine and red grape juice) also did not affect immunity. CONCLUSIONS: This study clearly shows that moderate consumption of alcohol at doses which inversely correlate with cardiovascular disease risk has no short-term effect on human immune cell functions. Acute intake of polyphenol-rich beverages such as red grape juice and dealcoholized red wine also does not affect immunity.

Alcohol Drinking↗

PubMed2002

Paraoxonase 1 Q192R (PON1-192) polymorphism is associated with reduced lipid peroxidation in R-allele-carrier but not in QQ homozygous elderly subjects on a tomato-rich diet.

BACKGROUND: The oxidative modification of LDL is considered to play a central role in the pathogenesis of atherosclerosis and coronary heart disease (CHD). Paraoxonase (PON1) protects LDL from oxidation and may therefore retard the development of atherosclerosis. The PON1-192 polymorphism is associated with diminished PON1 concentrations and an increased risk for CHD in RR-allele subjects. AIM OF THE STUDY: To investigate the effect of tomato juice consumption on PON1 activity and other parameters related to oxidative stress in healthy elderly subjects. Furthermore, the PON1-192 genotype has been determined in the volunteers in order to see whether possible treatment effects are related to the PON1-192 polymorphism. METHODS: Fifty elderly subjects were randomly assigned to control (mineral water) or intervention group (tomato juice). Subjects of the tomato juice group consumed daily 330 mL tomato juice for 8 weeks. Antioxidant status was measured as LDL oxidation, plasma malondialdehyde, ferric reducing ability of plasma (FRAP) and PON1 activity. The PON1-192 polymorphism was determined by restriction fragment length polymorphism polymerase chain reaction (RFLP-PCR). Plasma carotenoids were analyzed by HPLC. RESULTS: Tomato juice consumption reduced LDL-oxidation and improved antioxidant status in R-allele carriers, but not in the QQ genotype group. PON1 activity increased irrespective of the genotype in both, control and intervention group. CONCLUSIONS: The changes in antioxidant status after tomato juice consumption seem to depend on the PON1-192 genotype. Healthy elderly, carrying the R-allele, could specifically reduce their higher cardiovascular risk by changing dietary habits.

Aged↗

PubMed2002

Red wine polyphenols inhibit the growth of colon carcinoma cells and modulate the activation pattern of mitogen-activated protein kinases.

Red wine is a rich source of polyphenols, which exhibit a number of biological effects in different in vitro and in vivo systems. The bioavailability of polyphenols is poor and the plasma concentrations of major red wine polyphenols are usually low after consumption of dietary relevant amounts of red wine. In contrast to most organ systems, the gastrointestinal tract (particularly the epithelial cells of this organ system) is exposed to high concentrations of polyphenols. Here, we show that the total polyphenol pool isolated from a red wine (varity Lemberger, vintage 1998) at micromolar concentrations inhibited the proliferation of transformed colon epithelial cells HT 29 clone 19A induced by epidermal growth factor (EGF). Inhibition of proliferation was also associated with modulation of activation of mitogen-activated protein kinases (MAPK). Stress activated c-Jun N-terminal kinases 1/2 (JNK) and p38 MAPK were significantly activated by red wine polyphenols (6 mmol/L). Maximum phosphorylation of both MAPK was observed after a 1-h treatment with red wine polyphenols. In contrast, activation of extracellular signal regulated kinase (ERK) 1/2 by EGF (1 nmol/L) was significantly inhibited by red wine polyphenols (6 mmol/L). This signaling pattern, activation of JNK 1/2 and p38 MAPK and inhibition of ERK 1/2, is typical for antiproliferative compounds, indicating that red wine polyphenols may inhibit the proliferation of colon carcinoma cells by modulating MAPK intracellular signal transduction pathways.

Cell Division↗