Interrelationships between vitamin D3 and 25-hydroxyvitamin D3 during chronic ethanol administration in the rat

Characterizing neonatal vitamin D deficiency in the modern era: A maternal-neonatal birth cohort from Southern Europe

Absence of adequate maternal vitamin D supplementation and decreased maternal ultraviolet exposure during pregnancy are key determinants for the manifestation of neonatal hypovitaminosis D at birth. These parameters may vary, according to country-specific dietary patterns, health policies and sunshine exposure. We aimed to investigate differences in calcium metabolism and anthropometric profiles according to neonatal vitamin D status at birth, in a sunny region of Northern Greece. A secondary aim was to identify maternal parameters as risk factors for developing neonatal vitamin D deficiency at birth. A total of 129 mother-neonate pairs were included in the study and classified into three groups, according to neonatal 25-hydroxy-D [25(OH)D)] concentrations at birth [deficiency (<30 nmol/l), insufficiency (30-50 nmol/l) and sufficiency (>50 nmol/l)]. Neonatal biochemical and anthropometric profiles and maternal demographic, social, dietary and biochemical profiles were comparatively evaluated between the three groups. Univariate and multivariate logistic regression was performed to identify independent associations of maternal factors with neonatal vitamin D status. Vitamin D deficient-neonates manifested higher parathyroid hormone (7.20 ± 2.60 vs 5.50 ± 1.50 pg/ml, p = 0.01) and lower corrected calcium (10.70 ± 0.70 vs 11.30 ± 1.30 mg/dl, p = 0.02) concentrations compared with vitamin d-insufficient neonates. Mothers of vitamin D deficient and insufficient neonates had a lower total of 25(OH)D (31.7 ± 19.2 and 36.5 ± 22.3 vs 53.3 ± 39.0 nmol/l, p < 0.01) and 25(OH)D₃ (27.4 ± 17.5 and 33.3 ± 19.9 vs 47.3 ± 36.7 nmol/l, p < 0.01 and p = 0.04, respectively) concentrations respectively, compared with those of vitamin D-sufficient neonates. Maternal use of alcohol during pregnancy was associated with a 5.57-fold higher risk for neonatal vitamin D deficiency at birth (OR 5.57, 95 % CI1.17-26.56, p = 0.03). Newborns with vitamin D deficiency presented a 6.89-fold higher risk of having been given birth by vitamin D deficient mothers (OR 6.89, 95 % CI 3.09-15.38, p < 0.01). In conclusion, neonatal vitamin D deficiency is associated with maternal 25(OH)D concentrations at birth and maternal alcohol use. Further studies are required to replicate these findings in other regions and populations.

Multiple electrolyte imbalances and mixed acid-base disorder posing a diagnostic dilemma: a case report

Background

In clinical practice, both the history and laboratory testing are paramount to making an accurate diagnosis. Situations in which laboratory findings and patient history are not congruent pose a diagnostic dilemma. We report a case of a young woman presenting with a myriad of electrolyte and acid-base disorders. Difficulty in reaching a unifying diagnosis persisted due to discordant patient history. We believe this case shows that lab findings will clearly portray the problems a patient has and should be given more credence in a case where the history is discordant with lab findings.

Case presentation

A 28-year-old Hispanic American woman presented to the emergency room of our institution with a complaint of painless and sudden onset of stiffness in her upper and lower limbs. Associated weakness worse in the distal limbs was also reported. She experienced shortness of breath with minimal exertion, diaphoresis, and anxiety. Her vital signs revealed tachycardia without corresponding fever. She was conscious, oriented, and alert. Her physical exam revealed dry mucous membranes and warm extremities. She denied recent consumption of a large carbohydrate meal, diarrhea, vomiting, use of laxatives, and use of alcohol or recreational drugs. She vaguely described two previous similar episodes in the last 7 months that spontaneously resolved. Her medical history was significant only for hypothyroidism treated with daily levothyroxine tablets. Laboratory analysis revealed the following abnormalities: an elevated anion gap with significant lactate, hypokalemia, hypomagnesemia, elevated mean corpuscular volume, elevated mean cell hemoglobin, and elevated liver enzymes with aspartate aminotransferase/alanine aminotransferase ratio > 2. She was hydrated with balanced crystalloids, and her electrolyte deficiencies corrected. The etiology of her multiple electrolyte abnormalities was unclear because alcohol use was vehemently denied. Extensive evaluation for causes of electrolyte disorder was undertaken, which was unrevealing. On further interrogation, she admitted to recent alcohol intoxication and several episodes of vomiting before presentation. She was advised to refrain from alcohol use and discharged afterward.

Conclusion

Both patient history and laboratory analysis have a role in identifying and confirming a diagnosis. In cases in which laboratory tests are incongruous with reported history, making a unifying diagnosis can be challenging or delayed. The importance of taking a comprehensive history cannot be overemphasized, but history provided by patients may be prone to intentional or unintentional distortion, whereas laboratory findings are more objective. The case presented underscores why the lab findings should be given credence in cases in which there is discordance between lab results and the provided patient history.

Vitamin D Deficiency in Pregnant Ukrainian Women: Effects of Alcohol Consumption on Vitamin D Status

OBJECTIVE

Heavy alcohol consumption can alter vitamin D status; however, the relationships between alcohol consumption and vitamin D concentrations in pregnant women have not been well studied. The aim of this study was to investigate the vitamin D status in a population of alcohol-exposed (N = 180) and low/unexposed control (N = 179) Ukrainian pregnant women.

METHODS

Women who attended prenatal care facilities in 2 regions of Ukraine (Rivne and Khmelnytsky) for a routine prenatal visit were screened for the study. At the time of enrollment (20.4 ± 7.0 weeks of gestation), blood samples and alcohol consumption data (during a typical week around conception and the most recent 2 weeks) were collected. Vitamin D status was assessed by 25-hydroxyvitamin D [25(OH)D] concentrations.

RESULTS

A high prevalence of suboptimal vitamin D status in pregnant Ukrainian women was observed. Overall, 50.1% and 33.4% of the women were classified as vitamin D deficient [25(OH)D < 20 ng/mL] or insufficient [25(OH)D ≥ 20 ng/mL and ≤30 ng/mL], respectively, based on 2011 Endocrine Society guidelines. Alcohol-exposed women had significantly lower 25(OH)D concentrations than low/unexposed women in Spring (p = 0.006) and Winter (p = 0.022). When vitamin D concentrations were grouped into sunny season (Summer + Fall) compared to not sunny season (Winter + Spring), there was a significant ethanol by season interaction (p = 0.0028), with alcohol-drinking women having lower circulating vitamin D compared to low/unexposed women in seasons of low sun availability.

CONCLUSIONS

These data suggest that when vitamin D concentrations are generally low (e.g., during seasons of low sun availability), alcohol consumption during pregnancy has a negative impact on vitamin D status.

Chronic moderate ethanol intake differentially regulates vitamin D hydroxylases gene expression in kidneys and xenografted breast cancer cells in female mice

Factors affecting vitamin D metabolism may preclude anti-carcinogenic effects of its active metabolite calcitriol. Chronic ethanol consumption is an etiological factor for breast cancer that affects vitamin D metabolism; however, the mechanisms underlying this causal association have not been fully clarified. Using a murine model, we examined the effects of chronic moderate ethanol intake on tumoral and renal CYP27B1 and CYP24A1 gene expression, the enzymes involved in calcitriol synthesis and inactivation, respectively. Ethanol (5% w/v) was administered to 25-hydroxyvitamin D₃-treated or control mice during one month. Afterwards, human breast cancer cells were xenografted and treatments continued another month. Ethanol intake decreased renal Cyp27b1 while increased tumoral CYP24A1 gene expression.Treatment with 25-hydroxyvitamin D₃ significantly stimulated CYP27B1 in tumors of non-alcohol-drinking mice, while increased both renal and tumoral CYP24A1. Coadministration of ethanol and 25-hydroxyvitamin D₃ reduced in 60% renal 25-hydroxyvitamin D₃-dependent Cyp24a1 upregulation (P<0.05). We found 5 folds higher basal Cyp27b1 than Cyp24a1 gene expression in kidneys, whereas this relation was inverted in tumors, showing 5 folds more CYP24A1 than CYP27B1. Tumor expression of the calcitriol target cathelicidin increased only in 25-hydroxyvitamin D₃-treated non-ethanol drinking animals (P<0.05). Mean final body weight was higher in 25-hydroxyvitamin D₃ treated groups (P<0.001). Overall, these results suggest that moderate ethanol intake decreases renal and tumoral 25-hydroxyvitamin D₃ bioconversion into calcitriol, while favors degradation of both vitamin D metabolites in breast cancer cells. The latter may partially explain why alcohol consumption is associated with vitamin D deficiency and increased breast cancer risk and progression.

Prevalence and Determinants of Suboptimal Vitamin D Levels in a Multiethnic Asian Population

This population-based cross-sectional study examined the prevalence and risk factors of suboptimal vitamin D levels (assessed using circulating 25-hydroxycholecalciferol (25(OH)D)) in a multi-ethnic sample of Asian adults. Plasma 25(OH)D concentration of 1139 Chinese, Malay and Indians (40–80 years) were stratified into normal (≥30 ng/mL), and suboptimal (including insufficiency and deficiency, <30 ng/mL) based on the 2011 Endocrine Society Clinical Practice Guidelines. Logistic regression models were used to assess the associations of demographic, lifestyle and clinical risk factors with the outcome. Of the 1139 participants, 25(OH)D concentration was suboptimal in 76.1%. In multivariable models, age ≤65 years (compared to age >65 years), Malay and Indian ethnicities (compared to Chinese ethnicity), and higher body mass index, HbA1c, education and income levels were associated with suboptimal 25(OH)D concentration (p < 0.05). In a population-based sample of Asian adults, approximately 75% had suboptimal 25(OH)D concentration. Targeted interventions and stricter reinforcements of existing guidelines for vitamin D supplementation are needed for groups at risk of vitamin D insufficiency/deficiency.

Determinants of vitamin D status in young adults: influence of lifestyle, sociodemographic and anthropometric factors

BACKGROUND

Very few studies have investigated the determinants of circulating 25-hydroxyvitamin D (25[OH]D) in young adults (18-25 years old) using a set of variables that include lifestyle, sociodemographic, and anthropometric data. Our aim was to investigate the association between these variables and vitamin D status in a sample of untreated young adults.

METHODS

A total of 738 young adults were enrolled in a (June cross-sectional study 2012 to May 2014) and were recruited from educational institutions in the Copenhagen area. For multivariate logistic regression subjects was categorized based on 25[OH]D in serum into; vitamin D sufficiency (S-25[OH]D > 50 nmol/L), vitamin D insufficiency (25 nmol/L ≤ S-25[OH]D ≤ 50 nmol/L), vitamin D deficiency (S-25[OH]D < 25 nmol/L). Information on lifestyle factors and education was obtained by self-reported questionnaires.

RESULTS

700 subjects with a valid measurement of S-25[OH]D and a completed questionnaire was analysed. 238 had vitamin D insufficiency, 135 had vitamin D deficiency of which 13 had severe vitamin D deficiency (S-25[OH]D < 12.5 nmol/L). The relative risk (RR) for vitamin D deficiency was highest for men 2.09 (1.52, 2.87); obese subjects 2.00 (1.27, 3.15); smokers 1.33 (1.02, 1.73); subjects who exercised 0-½ hours a week 1.88 (1.21, 2.94); and subjects who consumed fast food once a week 1.59 (1.05, 2.43). The relative risk was significantly lower for subjects who were studying for a Bachelor's degree (0.40 (0.23, 0.68). For vitamin D insufficiency, the highest RR was again for men 1.31 (1.06, 1.61); obese subjects 1.57 (1.17, 2.11); and subjects who exercised 0-½ hours a week 1.51 (1.11, 2.06).

CONCLUSION

In this study of young adults, vitamin D deficiency was highly prevalent. Modifiable factors such as smoking, maintenance of normal BMI, and physical activity are all potential targets for interventional trials to determine the causal order; such knowledge would be useful in improving S-25[OH]D in young adults. The small group with severe vitamin D deficiency warrants increased attention.

Longitudinal associations between lifestyle and vitamin D: A general population study with repeated vitamin D measurements

Several lifestyle factors have been found to be associated with vitamin D status in cross-sectional studies, but it is not clear whether a change in these factors can actually affect the vitamin D level. We investigated the association between repeated measurements of physical activity, body mass index (BMI), diet, alcohol consumption, and smoking habits, and corresponding levels of vitamin D during 5 years of follow-up of a large general population sample. We included 4185 persons who participated and had vitamin D (serum-25-hydroxyvitamin D, 25-OH-D) measurements in the Inter99 study at baseline (1999-2001) and 5-year follow-up. In a subsample, 25-OH-D was also measured at 1- and 3-year follow-ups. We used mixed models to examine the association between repeated measurements of lifestyle factors and 25-OH-D levels. In multivariable analyses of repeated measurements, the difference in 25-OH-D was -0.32 ng/ml (95 % CI -0.37, -0.28) per 1 kg/m(2) increase in BMI; 4.50 ng/ml (95 % CI 3.84, 5.15) for persons moderately/vigorously physically active versus sedentary; 1.82 ng/ml (95 % CI 1.09, 2.56) for persons with healthy versus unhealthy dietary habits; 0.05 ng/ml (95 % CI 0.03, 0.07) per 1 standard drink/weak increase in alcohol consumption; and 0.86 ng/ml (95 % CI 0.36, 1.35) for never smokers versus daily smokers. Our study shows that lower BMI, a higher level of physical activity, a healthier diet and possibly a higher alcohol intake, and not smoking, are associated with higher 25-OH-D levels.

Metabolism of ethanol and associated hepatotoxicity

Over the last three decades, direct hepatotoxic effects of ethanol were established, some of which were linked to redox changes produced by NADH generated via the alcohol dehydrogenase (ADH) pathway and shown to affect the metabolism of lipids, carbohydrates, proteins, and purines. It was also determined that ethanol can be oxidized by a microsomal ethanol oxidizing system (MEOS) involving a specific cytochrome P-450; this newly discovered ethanol-inducible cytochrome P-450 (P-450 IIEi) contributes to ethanol metabolism, tolerance, energy wastage (with associated weight loss), and the selective hepatic perivenular toxicity of various xenobiotics. Their activation by P-450IIEi now provides an understanding of the increased susceptibility of the heavy drinker to the toxicity of industrial solvents, anaesthetic agents, commonly prescribed drugs, over-the-counter analgesics, and chemical carcinogens. P-450 induction also explains depletion (and toxicity) of nutritional factors such as vitamin A. As a consequence, treatment with vitamin A and other nutritional factors is beneficial, but must take into account a narrowed therapeutic window in alcoholics who have increased needs for nutrients and also display an enhanced susceptibility to some of their adverse effects. Acetaldehyde (the metabolite produced from ethanol by either ADH or MEOS) impairs hepatic oxygen utilization and forms protein adducts, resulting in antibody production, enzyme inactivation, and decreased DNA repair. It also stimulates collagen production by the vitamin A storing cells (lipocytes) and myofibroblasts, and causes glutathione depletion. Supplementation with S-adenosyl-L-methionine partly corrects the depletion and associated mitochondrial injury, whereas administration of polyunsaturated lecithin opposes the fibrosis. Thus, at the cellular level, the classic dichotomy between the nutritional and toxic effects of ethanol has now been bridged. The understanding of how the ensuing injury eventually results in irreversible scarring or cirrhosis may provide us with improved modalities for treatment and prevention.

Sex-specific relationships between alcohol consumption and vitamin D levels: The Korea National Health and Nutrition Examination Survey 2009

This study assessed the association between vitamin D sufficiency (serum 25(OH)D ≥30 ng/mL) and alcohol consumption using data from the Korea National Health and Nutrition Examination Survey conducted in 2009. The following characteristics were obtained in 7,010 Korean participants ≥19-years-of-age: serum 25(OH)D level, alcohol consumption (drinking frequency, drinking number of alcoholic beverages on a typical occasion, average daily-alcohol intake), and potential confounders (age, residence, housing status, occupation, total fat and lean mass, smoking, physical activity, history of liver diseases, liver function, and daily intake of energy, protein, and calcium). After adjusting for confounders, vitamin D sufficiency in men was significantly associated with drinking frequency, number of alcoholic drinks consumed, and average daily alcohol intake; odds ratio of 1.21-1.72, 2.17-3.04, and 2.27-3.09, respectively. Increase in the three alcohol drinking-related behaviors was also linearly associated with increase in serum 25(OH)D level in men. By comparison, there was no significant association between alcohol intake and serum 25(OH)D level in women. The positive association between vitamin D sufficiency and alcohol consumption was evident only in Korean men.

Serum 25-hydroxyvitamin d concentrations and season-specific correlates in Japanese adults

Background

Several lines of evidence indicate an important role for vitamin D in the prevention of a range of diseases. Blood vitamin D levels show clear seasonal variation; however, data on the determinants of vitamin D status for each season are limited. We investigated the association between lifestyle and serum vitamin D concentration by season in Japanese workers.

Methods

Subjects were 312 men and 217 women aged 21 to 67 years who worked in municipal offices in Northern Kyushu, Japan and participated in a periodic checkup in July or November. Multiple linear regression analysis was used to examine the association between serum 25-hydroxivitamin D concentrations and lifestyle factors for each season.

Results

Mean serum 25-hydroxyvitamin D concentration was 27.4 ng/ml (68.4 nmol/L) and 21.4 ng/ml (53.4 nmol/L) for workers surveyed in July and November, respectively (P < 0.001); the prevalence of vitamin D deficiency (<20 ng/ml) was 9.3% and 46.7%, respectively (P < 0.001). In November, dietary vitamin D intake (in both sexes) and nonsmoking and physical activity (in men) were significantly associated with higher concentrations of serum 25-hydroxyvitamin D. In summer, fish/shellfish intake was associated with higher serum 25-hydroxyvitamin D concentrations in women.

Conclusions

Vitamin D deficiency is common in Japanese workers during seasons with limited sunlight. The lifestyle correlates of favorable vitamin D status in November were physical activity, dietary vitamin D intake, and nonsmoking.

The role of nitric oxide on bone metabolism in ovariectomized rats following chronic ethanol intake

This experimental study was designed to examine the effect of nitric oxide (NO) on bone metabolism in ovariectomized rats following chronic ethanol treatment. Chronic ethanol intake was produced by gradual substitution (within 3 weeks) of tap water in diet with 5,10,15 and finally 20% of ethanol. Thereafter, the rats were maintained under these conditions for a duration of 4 months. The rats were divided into two groups. The first group received sham operation (SHAM) and the rats in Group II were ovariectomized (OVX). Five weeks after the SHAM and ovariectomy, the rats were treated with ethanol for 4 months. After this period of ethanol administration, the NOS inhibitor N(W)-nitro-L-arginine methyl ester (L-NAME) was given for three weeks along with ethanol to the same rats. Serum interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)-alpha, NO, calcium (Ca), phosphorous (P), parathyroid hormone (PTH), 25 HydroxyvitaminD3 [25(OH)D3], alkaline phosphatase (ALP), bone alkaline phosphatase (b-ALP), alanine amino transferase (ALT), aspartate amino transferase (AST), gamma-glutamyltransferase (GGT) levels were measured in different stages of the experiment. IL-1beta, IL-6, TNFalpha and NO levels increased after ethanol administration in SHAM and OVX rats. The decrease in serum Ca was significant while the changes in P, PTH and 25 (OH)D3 levels were not. ALP and b-ALP levels were significantly decreased; ALT, AST and GGT levels were significantly increased. In ovariectomized and SHAM rats, administration of L-NAME together with ethanol, produced a significant increase in IL-1beta, IL-6 and TNFalpha levels. In this group, Ca and P levels were significantly increased, PTH and 25 (OH)D3 levels were significantly decreased. Also, there was a significant decrease in ALT, AST, ALP, b-ALP, and GGT levels. NO increase due to alcohol intake may function as a protective mechanism preventing bone resorption in cases of estrogen insufficiency.

Effect of chronic alcohol ingestion on bone mineral density in males without liver cirrhosis

BACKGROUND

Osteoporosis in men is an important public health problem. Because of the tendency of the numbers of the elderly population to increase, and age-specific incidence of fractures, it is inevitable that the health burden due to fractures will increase. Chronic alcoholism is associated with other risk factors, such as poor nutrition, leanness, liver disease, malabsorption, vitamin D deficiency, hypogonadism, hemosiderosis, parathyroid dysfunction and tobacco use, and these may contribute to the pathogenesis of bone disease related to alcoholism. Chronic alcohol intake may reduce bone density, but can also increase bone density. It is well established that liver disease also induces bone density changes, thus it is difficult to distinguish the role of liver disease from that of alcohol itself in the bone alterations occurring in patients with chronic alcohol consumption. Chronic male alcoholics, not having liver cirrhosis were studied to assess the effect of chronic alcohol consumption on their bone mineral density.

METHODS

The study subjects comprised of 18 chronic heavy drinkers of more than 40 g of alcohol per day for at least 3 years and 18 age-matched controls who drank less than 20 g of alcohol per day. The serum and urinary parameters of bone and mineral metabolism were determined. The bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry at four axial sites (lumbar spine, femoral neck, Ward's triangle and trochanter).

RESULTS

The alcoholic and control patients drank an average of 97.6 g and 7.2 g of alcohol per day. Osteocalcin, a marker of bone formation, was slightly decreased in alcoholic patients, and deoxypyridinoline, a marker of bone resorption, was slightly increased, but the difference was not statistically significant (p > 0.05). There were no differences between the two groups in the levels of free testosterone, estradiol, 25(OH) vitamin D and parathyroid hormone. The Ward's triangle and trochanter BMDs of the femur were significantly lower in the alcoholics than the controls, and lumbar spine BMD was decreased in proportion to the total alcohol intake in the alcoholics (r = -0.625, p = 0.01).

CONCLUSION

We suggest that chronic alcohol consumption induces low bone density in the femur Ward's triangle and trochanter. There was also a significant inverse correlation between the lumbar spine BMD and the total amount of alcohol consumed. Large scaled randomized and prospective studies are needed to clarify the pathogenesis of alcohol-induced osteoporosis.

Alcohol, osteoporosis, and bone regulating hormones

The mechanism of the production of ethanol-associated osteopenia seems to be a direct effect of alcohol on bone cells and an indirect or modulating effect through mineral regulating hormones such as vitamin D metabolites, parathyroid hormone, and calcitonin. The modulating effects of these hormones on bone and mineral metabolism in acute and chronic alcohol consumption is discussed herein.

Alcohol consumption inhibits bone growth and development in young actively growing rats

Adolescence is an age of widespread alcohol abuse, but the effect of alcohol consumption on bone formation has not been studied in the young population. This study addresses the effect of alcohol on the early phases of bone growth and development in an animal model. Four-week-old, female Sprague-Dawley rats were divided into three groups. Alcohol-treated animals were fed a modified Lieber-DeCarli diet ad libitum containing 35% ethanol-derived calories, whereas the pair-fed animals (weight-matched to ethanol rats) received an isocaloric liquid diet in which maltose-dextrin substituted calories supplied by ethanol. Chow animals were fed a standard rat chow ad libitum. Proximal tibiae (primarily cancellous bone) and femora (primarily cortical bone) were removed for analysis after 2, 4, 6, or 8 weeks on the diets. Serum was collected for analysis of calcium levels, osteocalcin, corticosterone, growth hormone, parathyroid hormone, and 25-hydroxyvitamin D. The most rapid weight gain occurred between 6 and 8 weeks of age, it was significantly delayed in alcohol and pair-fed animals. Almost all morphological parameters of bone were lower in the alcohol groups. No significant difference in serum calcium levels, osteocalcin, or growth hormone levels were found, and small difference in calciotropic hormone levels was found between groups. The results indicated that chronic alcohol consumption during the age of bone development reduces bone density and peak bone mass in both cortical and cancellous bone. The mechanism whereby this effect occurs is not fully understood, but, our results suggest that the negative impact of alcohol on growing bone is not due to the secondary effects of altered bone mineral regulating hormones.

Toxicological effects of ethanol on human health

Moderate ethanol consumption reduces stress and increases feelings of happiness and well-being, and may reduce the risk of coronary heart disease. Heavy consumption of alcohol, however, may cause addiction and increases all types of injury and trauma. Environmental and genetic factors are involved in susceptibility to alcoholism. Ethanol can lead to malnutrition, and can exert a direct toxicological effect due to its interference with hepatic metabolism and immunological functions. A causal effect has been observed between alcohol and various cancers. Cessation of alcohol consumption and balanced nutrition are recommended primary nonspecific therapeutic measures for alcoholics. Drug therapies for alcoholics suffering from liver injury has resulted in mixed results. In end-stage liver disease, liver transplantation may be considered.

Bone mass improves in alcoholics after 2 years of abstinence

To evaluate the effect of abstinence on bone mass and bone mineral metabolism in chronic alcoholics, a 2 year longitudinal follow-up study was carried out in a group of 30 chronic alcoholic males who started a rehabilitation program. Lumbar and femoral bone mineral density (BMD) and serum levels of osteocalcin and 25-hydroxyvitamin D were measured at entry and after 1 and 2 years in all patients. Circulating cortisol and parathyroid hormone were measured in 14 and 6 patients, respectively, at entry and every year. Testosterone was measured in 18 patients at entry and after 1 year. At entry, lumbar BMD was significantly lower in alcoholics (1.06 +/- 0.03 g/cm2) than in age-matched healthy men (1.22 +/- 0.03 g/cm2; p < 0.001). Circulating osteocalcin and vitamin D levels were also significantly lower in alcoholics than in controls. Lumbar and femoral neck BMD increased in alcoholics after 2 years of abstinence (lumbar BMD, mean +/- SEM, 1.06 +/- 0.03 to 1.10 +/- 0.04 g/cm2, p < 0.05; femoral BMD, 0.82 +/- 0.02 to 0.84 +/- 0.02 g/cm2; p < 0.02). Moreover, lumbar BMD increased in alcoholics (2.9 +/- 1.4%) and decreased in controls (-1.1 +/- 0.2%; p < 0.02). Femoral BMD also increased in alcoholics (2.8 +/- 1.0%) but the expected mean decrease of -0.92% was found in healthy age-matched males. Baseline low osteocalcin levels (5.1 +/- 0.6 ng/ml) increased after 1 year (8.6 +/- 0.5 ng/ml, p < 0.001) and 2 years of abstinence (9.5 +/- 0.7 ng/ml, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aetiology and pathogenesis of alcoholic liver disease

Until the 1960s, liver disease of the alcoholic patient was attributed exclusively to dietary deficiencies. Since then, however, our understanding of the impact of alcoholism on nutritional status has undergone a progressive evolution. Alcohol, because of its high energy content, was at first perceived to act exclusively as 'empty calories' displacing other nutrients in the diet, and causing primary malnutrition through decreased intake of essential nutrients. With improvement in the overall nutrition of the population, the role of primary malnutrition waned and secondary malnutrition was emphasized as a result of a better understanding of maldigestion and malabsorption caused by chronic alcohol consumption and various diseases associated with chronic alcoholism. At the same time, the concept of the direct toxicity of alcohol came to the forefront as an explanation for the widespread cellular injury. Some of the hepatotoxicity was found to result from the metabolic disturbances associated with the oxidation of ethanol via the liver alcohol dehydrogenase (ADH) pathway and the redox changes produced by the generated NADH, which in turn affects the metabolism of lipids, carbohydrates, proteins and purines. Exaggeration of the redox change by the relative hypoxia which prevails physiologically in the perivenular zone contributes to the exacerbation of the ethanol-induced lesions in zone 3. In addition to ADH, ethanol can be oxidized by liver microsomes: studies over the last twenty years have culminated in the molecular elucidation of the ethanol-inducible cytochrome P450IIE1 (CYP2E1) which contributes not only to ethanol metabolism and tolerance, but also to the selective hepatic perivenular toxicity of various xenobiotics. Their activation by CYP2E1 now provides an understanding for the increased susceptibility of the heavy drinker to the toxicity of industrial solvents, anaesthetic agents, commonly prescribed drugs, 'over the counter' analgesics, chemical carcinogens and even nutritional factors such as vitamin A. Ethanol causes not only vitamin A depletion but it also enhances its hepatotoxicity. Furthermore, induction of the microsomal pathway contributes to increased acetaldehyde generation, with formation of protein adducts, resulting in antibody production, enzyme inactivation and decreased DNA repair; it is also associated with a striking impairment of the capacity of the liver to utilize oxygen. Moreover, acetaldehyde promotes glutathione depletion, free-radical mediated toxicity and lipid peroxidation. In addition, acetaldehyde affects hepatic collagen synthesis: both in vivo and in vitro (in cultured myofibroblasts and lipocytes), ethanol and its metabolite acetaldehyde were found to increase collagen accumulation and mRNA levels for collagen. This new understanding of the pathogenesis of alcoholic liver disease may eventually improve therapy with drugs and nutrients.

Alcohol, liver, and nutrition

Until two decades ago, dietary deficiencies were considered to be the major reason why alcoholics developed liver disease. As the overall nutrition of the population improved, more emphasis was placed on secondary malnutrition. Direct hepatotoxic effects of ethanol were also established, some of which were linked to redox changes produced by reduced nicotinamide adenine dinucleotide (NADH) generated via the alcohol dehydrogenase (ADH) pathway. It was also determined that ethanol can be oxidized by a microsomal ethanol oxidizing system (MEOS) involving cytochrome P-450: the newly discovered ethanol-inducible cytochrome P-450 (P-450IIE1) contributes to ethanol metabolism, tolerance, energy wastage (with associated weight loss), and the selective hepatic perivenular toxicity of various xenobiotics. P-450 induction also explains depletion (and enhanced toxicity) of nutritional factors such as vitamin A. Even at the early fatty-liver stage, alcoholics commonly have a very low hepatic concentration of vitamin A. Ethanol administration in animals was found to depress hepatic levels of vitamin A, even when administered with diets containing large amounts of the vitamin, reflecting, in part, accelerated microsomal degradation through newly discovered microsomal pathways of retinol metabolism, inducible by either ethanol or drug administration. The hepatic depletion of vitamin A was strikingly exacerbated when ethanol and other drugs were given together, mimicking a common clinical occurrence. Hepatic retinoid depletion was found to be associated with lysosomal lesions and decreased detoxification of chemical carcinogens. To alleviate these adverse effects, as well as to correct problems of night blindness and sexual inadequacies, the alcoholic patient should be provided with vitamin A supplementation. Such therapy, however, is complicated by the fact that in excessive amounts vitamin A is hepatotoxic, an effect exacerbated by long-term ethanol consumption. This results in striking morphologic and functional alterations of the mitochondria with leakage of mitochondrial enzymes, hepatic necrosis, and fibrosis. Thus, treatment with vitamin A and other nutritional factors (such as proteins) is beneficial but must take into account a narrowed therapeutic window in alcoholics who have increased needs for such nutrients, but also display an enhanced susceptibility to their adverse effects. Massive doses of choline also exerted some toxic effects and failed to prevent the development of alcoholic cirrhosis. Acetaldehyde (the metabolite produced from ethanol by either ADH or MEOS) impairs hepatic oxygen utilization and forms protein adducts, resulting in antibody production, enzyme inactivation, and decreased DNA repair. It also enhances pyridoxine and perhaps folate degradation and stimulates collagen production by the vitamin A storing cells (lipocytes) and myofibroblasts.(ABSTRACT TRUNCATED AT 400 WORDS)

Hepatic, metabolic and toxic effects of ethanol: 1991 update

Until two decades ago, dietary deficiencies were considered to be the only reason for alcoholics to develop liver disease. As the overall nutrition of the population improved, more emphasis was placed on secondary malnutrition and direct hepatotoxic effects of ethanol were established. Ethanol is hepatotoxic through redox changes produced by the NADH generated in its oxidation via the alcohol dehydrogenase pathway, which in turn affects the metabolism of lipids, carbohydrates, proteins, and purines. Ethanol is also oxidized in liver microsomes by an ethanol-inducible cytochrome P-450 (P-450IIE1) that contributes to ethanol metabolism and tolerance, and activates xenobiotics to toxic radicals thereby explaining increased vulnerability of the heavy drinker to industrial solvents, anesthetic agents, commonly prescribed drugs, over-the-counter analgesics, chemical carcinogens, and even nutritional factors such as vitamin A. In addition, ethanol depresses hepatic levels of vitamin A, even when administered with diets containing large amounts of the vitamin, reflecting, in part, accelerated microsomal degradation through newly discovered microsomal pathways of retinol metabolism, inducible by either ethanol or drug administration. The hepatic depletion of vitamin A is strikingly exacerbated when ethanol and other drugs were given together, mimicking a common clinical occurrence. Microsomal induction also results in increased production of acetaldehyde. Acetaldehyde, in turn, causes injury through the formation of protein adducts, resulting in antibody production, enzyme inactivation, decreased DNA repair, and alterations in microtubules, plasma membranes and mitochondria with a striking impairment of oxygen utilization. Acetaldehyde also causes glutathione depletion and lipid peroxidation, and stimulates hepatic collagen production by the vitamin A storing cells (lipocytes) and myofibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium status and calcium-regulating hormones in alcoholics

To elucidate effects of chronic ethanol consumption on clinical chemical parameters reflecting overall calcium homeostasis 34 hospitalized male alcoholics and 35 age-matched controls were studied during the winter season. Serum concentrations of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 were reduced by 28% (p less than 0.01) and 24% (p less than 0.02) among the alcoholics as compared to the controls, respectively. Dietary intake of vitamin D3 did not differ significantly between the groups. The calcium level was below lower limit of reference in nine alcoholics (26%). Serum concentrations of parathyroid hormone and phosphorus were within normal ranges in both groups, and no differences were observed in levels of magnesium, vitamin D-binding protein, calcitonin, or alkaline phosphatase. In conclusion, it is possible that the activities of enzymes crucial in vitamin D3 metabolism may be altered in alcoholics.

Chronic alcohol treatment results in disturbed vitamin D metabolism and skeletal abnormalities in rats

The effect of chronic alcohol consumption on the skeleton was investigated in rats. The treated group received ethanol administered as 38% of caloric intake in a liquid diet (Sustacal) for 10 months. The control rats were pair weighted to the ethanol-treated animals throughout the study; the growth curves of the two groups were the same. The controls were given the same liquid diet except that dextrin:maltose (3:1) was substituted isocalorically for ethanol. Ethanol-treated rats did not differ from the pair-weighted controls in mean serum calcium, phosphorous, or creatinine. In contrast, serum magnesium was reduced (p less than 0.02) in alcohol-treated rats. Ethanol treatment also resulted in changes in the serum concentrations of vitamin D metabolites; serum 25-hydroxyvitamin D3 was increased (p less than 0.001), while serum 1,25-dihydroxyvitamin D3 was decreased (p less than 0.01). Tibial length was reduced in ethanol-treated rats (p less than 0.05) but there was no change in femoral length. Medullary area was increased in tibial diaphyses from alcohol-treated rats compared to weight matched control animals (p less than 0.01), indicating a net increase in resorption. The cross-sectional area of the tibial diaphysis of ethanol-treated rats was the same as the matched controls. Trabecular bone was decreased in the tibial metaphysis of ethanol-treated rats compared to the matched controls (p less than 0.05) indicating a net loss of trabecular bone. Ethanol treatment did not have an effect on the organic weight of the femur but the ash weight was reduced (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

International Commission for Protection against Environmental Mutagens and Carcinogens. ICPEMC Working Paper No. 15/2. Metabolism and metabolic effects of ethanol, including interaction with drugs, carcinogens and nutrition

Different pathways of alcohol metabolism, the alcohol dehydrogenase pathway, the microsomal ethanol-oxidizing system and the catalase pathway are discussed. Alcohol consumption leads to accelerated ethanol metabolism by different mechanisms including an increased microsomal function. Microsomal induction leads to interactions of ethanol with drugs, hepatotoxic agents, steroids, vitamins and to an increased activation of mutagens/carcinogens. A number of ethanol-related complications may be explained by the production of its first metabolite, acetaldehyde, such as alterations of mitochondria, increased lipid peroxidation and microtubular alterations with its adverse effects on various cellular activities, including disturbances of cell division. Nutritional factors in alcoholics such as malnutrition are discussed especially with respect to its possible relation to cancer.

The microsomal ethanol oxidizing system and its interaction with other drugs, carcinogens, and vitamins

The interaction of ethanol with the oxidative drug-metabolizing enzymes present in liver microsomes results in a number of clinically significant side effects in the alcoholic. Following chronic ethanol consumption, the activity of the microsomal ethanol oxidizing system (MEOS) increases. This enhancement of MEOS activity is primarily due to the induction of a unique microsomal cytochrome P-450 isozyme, which has a high capacity for ethanol oxidation, as shown in reconstituted systems. Normally present in liver microsomes at low levels, this form of cytochrome P-450 increases dramatically after chronic ethanol intake in many species, including baboons. The in-vivo role of cytochrome P-450 in hepatic ethanol oxidation, especially following chronic ethanol consumption, has been conclusively demonstrated in deer-mice lacking liver ADH. Induction of microsomal cytochrome P-450 by ethanol is associated with the enhanced oxidation of other drugs as well, resulting in metabolic tolerance to these agents. There is also increased cytochrome P-450-dependent activation of known hepatotoxins such as carbon tetrachloride and acetaminophen, which may explain the greater susceptibility of alcoholics to the toxicity of industrial solvents and commonplace analgesics. In addition, the ethanol-inducible form of cytochrome P-450 has the highest capacity of all known P-450 isozymes for the activation of dimethylnitrosamine, a potent (and ubiquitous) carcinogen. Moreover, cytochrome P-450-catalyzed oxidation of retinol is accelerated in liver microsomes, which may contribute to the hepatic vitamin A depletion seen in alcoholics. In contrast to chronic ethanol consumption, acute ethanol intake inhibits the metabolism of other drugs via competition for shared microsomal oxidation pathways. Thus, the interplay between ethanol and liver microsomes has a profound impact on the way heavy drinkers respond to drugs, solvents, vitamins, and carcinogens.

Sequestration and microsomal C-25 hydroxylation of [3H]-vitamin D3 by the rat liver

A study of the vitamin D3 (D3) 25-hydroxylase was undertaken in an in vivo-in vitro model. [3H]-D3 (0.7, 1.0, 10, or 100 nmol/100 g of body weight) was injected into the portal vein and the liver was excised 18 seconds later. The liver homogenate was then submitted to differential centrifugation and the amount of [3H]-D3 incorporated in the subcellular fractions was evaluated. The microsomal fraction was also incubated in vitro and the appearance of [3H]-25-hydroxyvitamin D3 [25(OH)D3] was determined by high performance liquid chromatography (HPLC). Results showed that the fractional liver [3H]-D3 uptake varied between 37 percent and 48 percent of the dose injected. The intracellular distribution of [3H]-D3 showed that most of the vitamin was incorporated into the microsomal fraction (45% to 50% of the intracellular [3H]-D3) except at the highest dose of [3H]-D3 where the cytosolic fraction contained the highest amount (56.4%) of the incorporated vitamin. Mathematical analysis of the intracellular [3H]-D3 distribution showed that the microsomal fraction was the only subcellular fraction that was found to incorporate [3H]-D3 in relation to the total liver uptake of the vitamin. The apparent Michaelis-Menten kinetics of the [3H]-D3-25-hydroxylase showed that with substrate concentration of up to 88.5 nM, the apparent Km and Vmax were 28.2 nM and 25.8 fentomoles (fmol) X min-1 X mg microsomal pro-1, respectively, but the reaction lost considerable efficiency with higher substrate concentrations. With the in vivo-in vitro model used, the cytosolic fraction was not essential for the optimal C-25 hydroxylation of D3. These results show that the endoplasmic reticulum of rat hepatocytes possess a high capacity for D3 incorporation.(ABSTRACT TRUNCATED AT 250 WORDS)