Absorption, Pharmacokinetics, and Urinary Excretion of Pyridines After Consumption of Coffee and Cocoa-Based Products Containing Coffee in a Repeated Dose, Crossover Human Intervention Study.

SCOPE: The present study assesses the absorption, pharmacokinetics, and urinary excretion of coffee pyridines and their metabolites after daily regular exposure to specific dosages of coffee or cocoa-based products containing coffee (CBPCC), considering different patterns of consumption. METHODS AND RESULTS: In a three-arm, crossover, randomized trial, 21 volunteers are requested to randomly consume for 1 month: one cup of espresso coffee per day, three cups of espresso coffee per day, or one cup of espresso coffee plus two CBPCC twice per day. The last day of the one-month treatment, blood and urine samples are collected for 24 h. Trigonelline, N-methylpyridinium, N-methylnicotinamide, and N-methyl-4-pyridone-5-carboxamide are quantified. Trigonelline and N-methylpyridinium absorption curves and 24-h urinary excretion reflect the daily consumption of different servings of coffee or CBPCC, showing also significant differences in main pharmacokinetic parameters. Moreover, inter-subject variability due to sex and smoking is assessed, showing sex-related differences in the metabolism of trigonelline and smoking-related ones for N-methylpyridinium. CONCLUSION: The daily exposure to coffee pyridines after consumption of different coffee dosages in a real-life setting is established. This data will be useful for future studies aiming at evaluating the bioactivity of coffee-derived circulating metabolites in cell experiments, mimicking more realistic experimental conditions.

Consumption of a dark roast coffee decreases the level of spontaneous DNA strand breaks: a randomized controlled trial.

PURPOSE: Coffee consumption has been reported to decrease oxidative damage in peripheral white blood cells (WBC). However, effects on the level of spontaneous DNA strand breaks, a well established marker of health risk, have not been specifically reported yet. We analyzed the impact of consuming a dark roast coffee blend on the level of spontaneous DNA strand breaks. METHODS: Healthy men (n = 84) were randomized to consume daily for 4 weeks either 750 ml of fresh coffee brew or 750 ml of water, subsequent to a run in washout phase of 4 weeks. The study coffee was a blend providing high amounts of both caffeoylquinic acids (10.18 ± 0.33 mg/g) and the roast product N-methylpyridinium (1.10 ± 0.05 mg/g). Before and after the coffee/water consumption phase, spontaneous strand breaks were determined by comet assay. RESULTS: At baseline, both groups exhibited a similar level of spontaneous DNA strand breaks. In the intervention phase, spontaneous DNA strand breaks slightly increased in the control (water only) group whereas they significantly decreased in the coffee group, leading to a 27% difference within both arms (p = 0.0002). Food frequency questionnaires indicated no differences in the overall diet between groups, and mean body weight during the intervention phases remained stable. The consumption of the study coffee substantially lowered the level of spontaneous DNA strand breaks in WBC. CONCLUSION: We conclude that regular coffee consumption contributes to DNA integrity.

Urinary N-methylpyridinium and trigonelline as candidate dietary biomarkers of coffee consumption.

SCOPE: In order to validate the in vivo function of putatively healthy molecules in foods, human intervention studies are required. As the subject's compliance concerning intake or abstinence of a given food is considered mandatory to be monitored by biomarkers, the objective was to identify analytical markers for coffee consumption. METHODS AND RESULTS: Urine samples collected from coffee drinkers were compared with those of non-coffee drinkers using hydrophilic liquid interaction chromatography (HILIC)/time-of-flight mass spectrometry-based metabolite profiling. Two urinary molecules, found to be contributing most to the dissimilarities between both groups, were identified as N-methylpyridinium (NMP) and trigonelline and their suitability as coffee-specific biomarkers was validated by means of a coffee intervention study. After the volunteers (five females and four males) consumed a single dose of coffee, morning urine was collected for 10 days while staying abstinent from any coffee. HILIC-MS/MS-stable isotope dilution analysis (SIDA) revealed elevated urinary concentrations of trigonelline and NMP for up to 48 (p=0.001) and 72 h (p=0.002), respectively, after coffee consumption when compared with non-coffee drinkers. CONCLUSION: Analysis of urinary NMP allows to check for coffee consumption within a period of 3 days and is proposed as a dietary biomarker which might be used as an analytical probe to control compliance in human intervention studies on coffee.

Bone turnover and density in obese premenopausal women during moderate weight loss and calcium supplementation.

Bone turnover is increased during weight loss in postmenopausal women and can be suppressed with calcium supplementation. In this study, we assessed the influence of energy restriction with and without calcium supplementation (1 g/day) in premenopausal women. Thirty-eight obese premenopausal women (body mass index [BMI] of 35.0 +/- 3.9 kg/m2) completed a 6-month study of either moderate weight loss or weight maintenance. During weight loss, women were randomly assigned to either a calcium supplementation (n = 14) or placebo group (n = 14) and lost 7.5 +/- 2.5% of their body weight. The control group of women (n = 10) maintained their body weight. Total body and lumbar bone mineral density (LBMD) and content were measured by dual-energy X-ray absorptiometry (DXA) at baseline and after weight loss. Throughout the study, blood and urine samples were collected to measure bone turnover markers and hormones. During moderate energy restriction, dietary calcium intake decreased (p < 0.05) and the bone resorption marker deoxypyridinoline (DPD) increased slightly (p < or = 0.05) without evidence of bone loss. Calcium supplementation during weight loss tended to increase lumbar BMD by 1.7% (p = 0.05) compared with the placebo or weight maintenance groups. In contrast to our previous findings in postmenopausal women, premenopausal obese women who consume a low calcium diet do not lose bone over a 6-month period, whether their weight is stable or decreasing moderately.

High phosphorus intake only slightly affects serum minerals, urinary pyridinium crosslinks and renal function in young women.

OBJECTIVE: Assessment of the physiological effects of a diet rich in phosphorus in young women. DESIGN: Control period I--commercial basic diet containing 1700 mg P and 1500 mg Ca/day for 4 weeks. Supplementation period--a 6 week high-phosphorus period of 3008 mg P and 1995 mg Ca/day. Control period II--4 weeks washout with basic diet as in period I. SETTING: Institute of Nutritional Science, Friedrich Schiller University, Jena. SUBJECTS: Ten healthy women, aged 20-30y. INTERVENTIONS: Orange juice and tablets, containing supplements of Ca5(PO4)3OH and NaH2PO4, totalling 1436 mg elemental phosphorus per day. RESULTS: There was an increase of 10.7+/-13.7 pg/ml in serum PTH, a decrease of 0.6+/-0.6 ng/ml in serum osteocalcin, an increase of 73.6+/-136.6 nmol/mmol creatinine in urinary pyridinoline and of 19.3+/-36.0 nmol/ mmol creatinine in urinary deoxypyridinoline, and a decrease of 2.6+/-9.3 mg/l in urinary microalbumin. All changes were insignificant. There were no changes in serum levels of Ca, PO4 or Zn, in serum concentration of 1,25-(OH)2D3, and in urinary beta-2-microglobulin excretion. Phosphorus supplementation caused intestinal distress, soft stools or mild diarrhoea. CONCLUSIONS: In spite of a high phosphorus supplementation no significant changes in bone-related hormones, pyridinium crosslinks as markers of bone resorption and parameters of renal function in young women were found.

Inhibitory effects of JTE-522, a novel prostaglandin H synthase-2 inhibitor, on adjuvant-induced arthritis and bone changes in rats.

OBJECTIVE AND DESIGN: To investigate the effect of JTE-522, a novel selective prostaglandin H synthase (PGHS)-2 inhibitor, on adjuvant-induced arthritis and bone changes. SUBJECTS: Male Lewis rats at 8 weeks old were immunized with heat-killed mycobacteria. TREATMENT: JTE-522 (0.1-30 mg/kg) and indomethacin (0.1-3 mg/kg) were administered orally once-daily after immunization. METHODS: Paw swelling, bone changes in arthritic paws and vertebrae, urinary levels of deoxypyridinoline and pyridinium crosslinks, and the incidence of gastric lesions were determined in arthritic rats. RESULTS: JTE-522 (from 0.3 mg/kg) suppressed the development of paw swelling, and also reduced bone damage (score and bone mineral density) in arthritic paws and the urinary excretion of deoxypyridinoline and pyridinium crosslinks. However, JTE-522 did not cause gastric lesions even at 30 mg/kg in arthritic rats. CONCLUSIONS: These results suggest that JTE-522 possesses potent anti-arthritic activities and suppressive activity on inflammatory bone resorption without gastric side effects.

Calcium supplementation suppresses bone turnover during weight reduction in postmenopausal women.

Bone mobilization, lowering of bone mineral density (BMD), and osteoporotic fractures are recognized in postmenopausal women with weight loss. Because a high-calcium intake suppresses bone loss in peri- and postmenopausal women, the present randomized, double-blind, placebo-controlled study was designed to test the hypothesis that calcium supplementation prevents net bone mobilization and consequent bone mineral loss during voluntary weight reduction in obese postmenopausal women. Subjects were placed on a moderate energy-restricted diet and either calcium supplementation (1 g/day) or placebo for 6 months. Body weight, bone turnover markers (pyridinium cross-links), osteocalcin, and parathyroid hormone (PTH) were measured at treatment weeks 1-5, 7, 10, 13, 16, 20, and 25. Total body BMD, insulin-like growth factor, 25-hydroxyvitamin D, and sex hormone binding globulin (SHBG) were measured at baseline and week 25. The calcium supplemented (n = 15; age 60.9 +/- 9.4 years, body mass index [BMI] 33.2 +/- 4.6 kg/m2) and placebo (n = 16; age 55.8 +/- 8.3 years, BMI 32.9 +/- 4.5 kg/m2) groups lost similar amounts of weight over the study interval (10.2 +/- 5.3% vs. 10.0 +/- 5.2%) and both groups increased SHBG (p < 0.001). There was a statistical effect of calcium supplementation during weight loss to suppress pyridinium cross-links, osteocalcin, and PTH (p < 0.05, < 0.01, and < 0.05, respectively). Loss of BMD tended to be greater in the placebo group by 1.4% (p < 0.08) after weight loss. One gram per day calcium supplementation normalizes the increased calcium-PTH axis activity and the elevated bone turnover rate observed during moderate voluntary energy restriction in postmenopausal women.

Effects of tiaprofenic acid on urinary pyridinium crosslinks in adjuvant arthritic rats: comparison with doxycycline.

OBJECTIVE AND DESIGN: To study the effects of tiaprofenic acid and doxycycline on urinary pyridinium crosslinks and paw swelling in adjuvant arthritic rats, and to gain additional information on the drugs' inhibitory potential vs. in vitro targets, such as enzyme activity of matrix metalloproteinases and cytokine generation. MATERIAL: 124 male Wistar Lewis rats; for the in vitro studies human matrix metalloproteinases and human mononuclear cells were used. TREATMENT: Arthritis was induced by injection of complete Freund adjuvant. Drugs (2, 15, 50 mg tiaprofenic acid/kg; 5, 15, 30 mg doxycycline/kg) were administered daily p.o. until day 21. In the in vitro studies 10-1000 mumoles/l of these drugs were used. METHODS: Urinary levels of pyridinoline and deoxypyridinoline, determined by HPLC/fluorescence, and paw volumes were the measurements in the rat study. In the in vitro studies enzyme activities were assessed using fluorogenic peptide substrates; cytokines were determined by ELISA. RESULTS: On day 21 of disease crosslink excretion was about twofold higher compared to the healthy controls. After administering daily 15 or 30 mg/kg tiaprofenic acid p.o. this increase was almost completely prevented whereas the paw volumes were suppressed by about 50%. Up to 50 mg/kg doxycycline did not display significant suppressive effects on crosslinks and paw volumes. In vitro 50-100 mumol/l of both drugs inhibited the activities of selected metallo-proteinases, but only doxycycline suppressed the generation of IL-1 beta/TNF alpha in human mononuclear cells, whereas tiaprofenic acid was virtually inactive in that model. CONCLUSIONS: In arthritic rats tiaprofenic acid has not only the capability to suppress paw inflammation, but also to prevent with high potency the excretion of pyridinium crosslinks. Doxycycline without inherent antiinflammatory activity does not exhibit such preserving effects on collagen degradation in this model. Thus the mode of action of cartilage protecting drugs within the complex pathogenesis of arthritis will need further elucidation.

Changes in urinary excretion of pyridinium cross-links during Spacelab-J.

In SLJ-1 we proposed to study three major objectives. They were; 1. hormonal changes associated with fluid and electrolyte metabolism, 2. the effect of space flight on the circadian rhythms of endocrine and metabolic systems, 3. the changes in the indices of the bone and muscle metabolism during space flight. In this report, the changes in the bone metabolism during Spacelab-J will be presented with a special emphasis on urinary excretion of pyridinium cross-links. Timed urine samples from three Japanese payload specialists were obtained for 3 days from May 19 to 21, 1991 (one year before the launch = L-1 year). Immediately before the launch (L-3 to L-0), urine samples were obtained from a payload specialist who was on board the Space Shuttle Endeavor (PS). During the inflight period (flight from September 3 to 10 in 1992), urine samples from the PS were collected by using Urine Monitoring System (UMS). After the landing, they were obtained from the PS for three days (R+0-R+2). Various parameters related to bone metabolism such as hydroxyproline, pyridinium cross-links and calcium were determined. It was noted that excretion of hydroxyproline decreased during the preflight periods when compared with that in the control L-1 year period. The average excretory rate during control period was 846.2 +/- 198.7 milligrams/hour (mean +/- SD), while those in the preflight 474.6 +/- 171.1 milligrams/hour, suggesting the diminished collagen intake during the preflight period. Average excretion rate of pyridinium cross-links during the first 4 mission days (MD0-MD3) was similar to that of preflight and control L-1 year period. However, it was significantly increased during the last 4 mission days (MD4-MD7). It returned to the preflight level during postflight days (R+0-R+2). Increased urinary excretion of calcium during the last 4 mission days were also observed. These results suggest that increase in bone resorption could occur during relatively short stay in microgravity.

The influence of a low-boron diet and boron supplementation on bone, major mineral and sex steroid metabolism in postmenopausal women.

An increase in dietary intake of B from 0.25 to 3.25 mg/d has been reported to increase plasma oestradiol and testosterone and decrease urinary Ca excretion in postmenopausal women. Consequently, it is suggested that the higher level of B intake could reduce bone loss associated with the menopause and cessation of ovarian function. The present study was designed to investigate the effect of a B supplement on bone mineral absorption and excretion, plasma sex steroid levels and urinary excretion of pyridinium crosslink markers of bone turnover in healthy postmenopausal volunteers. The women were accommodated in a metabolic unit, given a low-B diet (LBD; 0.33 mg/d) for 3 weeks and were asked to take a B supplement of 3 mg/d in addition to the LBD for a further 3 weeks. Changing B intake from 0.33 to 3.33 mg/d had no effect on minerals, steroids or crosslinks. However, the LBD appeared to induce hyperabsorption of Ca since positive Ca balances were found in combination with elevated urinary Ca excretion. This phenomenon may have inhibited or obscured any effect of B.