Differential effects of the 1,25D3-MARRS receptor (ERp57/PDIA3) on murine mammary gland development depend on the vitamin D3 dose.

1,25 dihydroxyvitamin D3 (1,25D3) is the most potent biologically active form of vitamin D3. Its actions on the mammary gland include cell growth inhibition and anti-cancer effects. This study's purpose was to explore the role of the 1,25D3-membrane associated rapid response steroid (MARRS) receptor in the mammary gland using a tissue-specific knockout mouse model and a vitamin D3 dietary intervention. Three genotype groups were created using the Cre/loxp system to knock-down (+/-) and knockout (-/-) the MARRS receptor in epithelial cells of mammary glands (MG). Abdominal MGs were collected from 6-week old female mice (n = 94) on diets of 10,000 IU/kg (excess), 1,000 IU/kg (sufficient) or 0 IU/kg (deficient) of D3. There was a significant interaction between genotype and diet regarding number of terminal end buds (TEBs) (p = 0.001) and ductal coverage of the fat pad (p = 0.03). MARRS -/- mice on the sufficient diet had significantly fewer TEBs (p = 0.001) compared to MARRS +/+ on the same diet, but the opposite effect was seen in mice on the excess diet. There were no effects of genotype on TEBs when animals were vitamin D3 deficient. These results suggest that there is an effect of MARRS on mammary gland development that is dependent on 25(OH)D status, specifically, altering the number of highly proliferative TEBs. Increased numbers of TEBs have been correlated with increased breast cancer risk later in life. Therefore the results of this study warrant further examination of 25(OH)D status and recommendations in adolescent humans to reduce dietary effects on future breast cancer risk.

Proteomic Profiles of Adipose and Liver Tissues from an Animal Model of Metabolic Syndrome Fed Purple Vegetables.

Metabolic Syndrome (MetS) is a complex disorder that predisposes an individual to Cardiovascular Diseases and type 2 Diabetes Mellitus. Proteomics and bioinformatics have proven to be an effective tool to study complex diseases and mechanisms of action of nutrients. We previously showed that substitution of the majority of carbohydrate in a high fat diet by purple potatoes (PP) or purple carrots (PC) improved insulin sensitivity and hypertension in an animal model of MetS (obese Zucker rats) compared to a control sucrose-rich diet. In the current study, we used TMT 10plex mass tag combined with LC-MS/MS technique to study proteomic modulation in the liver (n = 3 samples/diet) and adipose tissue (n = 3 samples/diet) of high fat diet-fed rats with or without substituting sucrose for purple vegetables, followed by functional enrichment analysis, in an attempt to elucidate potential molecular mechanisms responsible for the phenotypic changes seen with purple vegetable feeding. Protein folding, lipid metabolism and cholesterol efflux were identified as the main modulated biological themes in adipose tissue, whereas lipid metabolism, carbohydrate metabolism and oxidative stress were the main modulated themes in liver. We propose that enhanced protein folding, increased cholesterol efflux and higher free fatty acid (FFA) re-esterification are mechanisms by which PP and PC positively modulate MetS pathologies in adipose tissue, whereas, decreased de novo lipogenesis, oxidative stress and FFA uptake, are responsible for the beneficial effects in liver. In conclusion, we provide molecular evidence for the reported metabolic health benefits of purple carrots and potatoes and validate that these vegetables are good choices to replace other simple carbohydrate sources for better metabolic health.

Role of the ERp57 protein (1,25D3-MARRS receptor) in murine mammary gland growth and development.

The protein disulfide isomerase ERp57 (GRp58/PDIA3/1,25D3-MARRS) has been implicated in a multitude of signaling pathways throughout the entire body. Most thoroughly studied for its protein-folding role, ERp57 has also been found to have multiple binding partners, and have significant effects on cellular growth. ERp57 has been studied n the context of several neurodegenerative disorders, metabolic conditions, and can be used as a prognosis marker in certain cancers. One role, as an alternate vitamin D binding receptor, has prompted research in tissues with known vitamin D activity, such as the intestine and bone. Vitamin D has been studied in relation to mammary gland growth and development, but it is not yet known if ERp57 plays an independent role in this tissue. In this study, ERp57 was knocked out in murine mammary gland epithelial cells of 30 4-week old mice. Several markers of mammary gland growth were measured, including number of terminal end buds (TEB), ductal coverage of the fat pad, and ductal extension. It was found the knockout animals had decreased numbers of TEBs (p = 0.019), and decreased ductal extension (p = 0.018) compared to wildtype animals, with no differences in gross body weight. Immunohistochemistry analysis of mammary glands showed ERp57 localized to the apical side of alveolar branches, and on leading edges of TEBs. These results provide further evidence for ERp57 functioning separately to the VDR, and further insights into the roles of ERp57.

The Effect of Anthocyanin-Rich Purple Vegetable Diets on Metabolic Syndrome in Obese Zucker Rats.

Consumption of highly colored fruits and vegetables rich in anthocyanins has been associated with numerous health benefits. Purple carrots (PC) and purple potatoes (PP) have higher anthocyanin concentrations and higher biological activities compared with less pigmented cultivars. We hypothesized that substitution of the majority of carbohydrate in a high fat diet with PP or PC, for 8 weeks, would improve insulin resistance and hypertension, major components of metabolic syndrome, compared with orange carrots (OC), white potatoes (WP) or a control, high fat, sucrose-rich diet (HFD) in obese Zucker rats. After 8 weeks of feeding, intraperitoneal glucose tolerance test, intraperitoneal insulin tolerance test (ipITT), and invasive hemodynamic tests were performed. The PP group had better glucose tolerance compared with the WP and the HFD groups and higher insulin sensitivity as measured by the ipITT and homeostatic model assessment of insulin resistance (P = .018) compared with the HFD without having any effect on blood pressure. The PC reduced left ventricular pressure compared with both the HFD (P = .01) and the OC (P = .049) groups and reduced systolic and diastolic blood pressures compared with the HFD group (P = .01 and <.0001, respectively) without having any effect on glucose homeostasis. The PC animals consumed more and were more obese than other groups, possibly obscuring any benefit of this vegetable on glucose tolerance. The bioactives in the vegetables responsible for blood pressure and glucose homeostasis could be different, and their effects could be independent of each other. The specific bioactives of each vegetable and their molecular targets remain to be identified. Nonetheless, incorporation of purple vegetables in functional food products may provide metabolic/cardiovascular benefits in the background of a high-fat diet that promotes obesity.

The role of background diet on the effects of eicosapentaenoic acid and docosahexaenoic acid supplementation in healthy pre-menopausal women: a randomized, cross-over, controlled study.

BACKGROUND: The links between dietary fat intake, polyunsaturated fatty acid intake and breast cancer risk remain equivocal, with some studies pointing to improvements in risk upon omega-3 supplementation. However, the background diet is poorly controlled in most studies, potentially confounding this link. Therefore, this study examined the hypothesis that in order to see the benefits of omega-3 fatty acid supplementation, the background diet must be low in fat. METHODS: Of the 56 healthy, pre-menopausal women randomized to one of two experimental arms, consisting of a two-treatment, randomized, cross-over design, 41 completed the 10 month intervention. The two diet phases (habitual and low-fat) were separated by a washout phase, each lasting 3 menstrual cycles. During each diet phase, women were supplemented with 1.2 g eicosapentaenoic acid + docosahexaenoic acid per day. RESULTS: Red blood cell fatty acid composition indicated that more eicosapentaenoic acid and docosahexaenoic acid was incorporated in the low-fat diet than the habitual diet, though both diet phases resulted in significant increases in the omega-3 to omega-6 ratio. In the context of omega-3 supplementation in breast cancer risk reduction, we also measured fatty acid incorporation into nipple aspirate fluid. Similar changes to red blood cells were noted in nipple aspirate fluid, with higher incorporation of eicosapentaenoic acid in the low-fat diet phase. CONCLUSIONS: These data suggest that the total level of dietary fat has some direct impact on fatty acid partitioning in addition to the recognized importance of fatty acid ratios, and supports the hypothesis that dietary fat intake must be considered a confounder in supplementation trials. Additionally, we demonstrate that n3 supplementation both reaches and imparts improvements in lipid content and n3:n6 at the target breast tissue. TRIAL REGISTRATION: Trial was been retrospectively registered at clinicaltrials.gov (Reg NCT02816125 ).

Bioefficacy of tea catechins encapsulated in casein micelles tested on a normal mouse cell line (4D/WT) and its cancerous counterpart (D/v-src) before and after in vitro digestion.

Numerous studies have demonstrated that tea catechins form complexes with milk proteins, especially caseins. Much less work has been conducted to understand the metabolic conversions of tea-milk complexes during gastro-duodenal digestion. The objective of this study was to determine the significance of this association on the digestibility of the milk proteins and on the bioaccessibility of the tea polyphenol epigallocatechin gallate (EGCG). An in vitro digestion model mimicking the gastric and duodenal phases of the human gastrointestinal tract was employed to follow the fate of the milk proteins during digestion and determine the bioefficacy of EGCG isolated or encapsulated with the caseins. The samples, before and after digestion, were tested using two parallel colonic epithelial cell lines, a normal line (4D/WT) and its cancerous transformed counterpart (D/v-src). EGCG caused a decrease in proliferation of cancer cells, while in normal cells, neither isolated nor encapsulated EGCG affected cell proliferation, at concentrations <0.15 mg ml(-1). At higher concentrations, both isolated and encapsulated produced similar decreases in proliferation. On the other hand, the bioefficacy on the cancer cell line showed some differences at lower concentrations. The results demonstrated that regardless of the extent of digestion of the nanoencapsulated EGCG, the bioefficacy of EGCG was not diminished, confirming that casein micelles are an appropriate delivery system for polyphenols.

Antioxidant capacity of food mixtures is not correlated with their antiproliferative activity against MCF-7 breast cancer cells.

Combining different foods may produce additive, synergistic, or antagonistic interactions that may modify certain physiological effects (i.e., anticancer properties). For investigating these interactions and potential synergetic combinations, thirteen foods from three categories, including fruits (raspberries, blackberries, apples, grapes), vegetables (broccoli, tomatoes, mushrooms, purple cauliflowers, onions), and legumes (soy beans, adzuki beans, red kidney beans, black beans), were evaluated for their inhibitory activity against MCF-7 breast cancer cells. Grape, onion, and adzuki bean showed maximal growth inhibition of MCF-7 from the fruit, vegetable, and legume groups, respectively. When these three foods were combined in pairs, unique interactions were observed that were not seen when individual extracts were used. Combining onion and grape resulted in a synergistic antiproliferative effect (APE) against MCF-7 compared with either onion or grape treatment alone. In contrast, combining grape and adzuki bean resulted in an antagonistic interaction. Additionally, four antioxidant assays (total phenolic contents, ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl, and oxygen radical absorbance capacity) were further used to evaluate the antioxidant capacities (AC) of individual foods and their combinations. Combining raspberry and adzuki bean extracts demonstrated synergistic AC in all four assays, but they did not show synergistic APE against the MCF-7 cells. Combining broccoli and soy produced antioxidant antagonism, but did not have an antagonistic APE against MCF-7. The synergistic or antagonistic AC of food mixtures did not correlate with the synergistic or antagonistic APE against MCF-7. Further investigation is to determine the mechanisms of these interactions and to predict and enhance the therapeutic benefits of foods and food components through strategic food combinations.

In vitro antioxidant synergism and antagonism between food extracts can lead to similar activities in H2O2-induced cell death, caspase-3 and MMP-2 activities in H9c2 cells.

BACKGROUND: The cardio-health-promoting activity of some foods may be due to their specific antioxidant content. The antioxidant activity of a mixture of plant extracts has been shown to differ from the activity of the individual extracts. As a result, the activity of the mixture can be described as synergistic, antagonistic or additive. This in vitro study evaluated the relationship between the in vitro antioxidant capacity of mixtures and their bioactivity when cardiomyocytes (H9c2) were challenged with H(2)O(2). RESULTS: A mixture of raspberry and adzuki bean extracts produced a synergistic response and a mixture of broccoli and soybean extracts produced an antagonistic response in chemical-based antioxidant assays. When these extracts were tested in cell cultures, individually and in mixtures, the mixture of raspberry and adzuki bean protected the cardiomyocytes from H(2)O(2)-induced cell damage significantly better than the individual extracts. Conversely, the mixture of broccoli and soybean extracts was less effective in protecting H9c2 cells. The synergistic and antagonistic effects of the mixtures in protecting cell damage were brought about by enhanced or reduced ability in attenuating caspase-3 and matrix metalloproteinase-2 activities elevated by H(2)O(2). CONCLUSION: Food mixtures with synergistic antioxidant activity and protective property against reactive oxygen species-induced cell death can potentially be incorporated into novel functional foods or beverages with optimum health benefit. The antagonistic effect of food mixtures can be a health concern and thus should be avoided.

Effect of the protein:carbohydrate ratio in hypoenergetic diets on metabolic syndrome risk factors in exercising overweight and obese women.

Overweight and obesity are growing problems both in Canada and around the world. Obesity is associated with a number of chronic diseases including type 2 diabetes and CVD, which puts a tremendous burden on the health care systems in place. The present study sought to investigate whether there were differences in the effectiveness of three low-fat, hypo- and isoenergetic diets differing in protein:carbohydrate ratio, low protein (LP, 1 g protein:4 g carbohydrate), normal protein (NP, 1 g protein:2 g carbohydrate) or high protein (HP, 1 g protein:1 g carbohydrate), on weight loss and markers of the metabolic syndrome (MetS) in overweight women. Subjects were randomly assigned to receive one of three intervention diets, all of which included a 60 min exercise programme three times/week for 12 weeks. Of the total subjects, fifty-four overweight and obese local women with MetS risk factors completed the study. All groups had similar improvements in body weight, insulin sensitivity, lipid profile, blood pressure and fitness. Subjects reported that the NP diet was easier to comply with and achieved better improvements in body fat, waist circumference and waist:hip ratio, and preservation of lean mass compared with the other two diets. In conclusion, energy restriction and exercise both facilitate weight loss in overweight and obese subjects and reduce symptoms of the MetS. A diet with a 1:2 protein:carbohydrate ratio promoted better improvements than either the LP or HP diets, and may be superior in reducing long-term chronic disease risk in this population.

Synergistic, additive, and antagonistic effects of food mixtures on total antioxidant capacities.

Different foods possess different bioactive compounds with varied antioxidant capacities. When foods are consumed together, the total antioxidant capacity of food mixtures may be modified via synergistic, additive, or antagonistic interactions among these components, which may in turn alter their physiological impacts. The main objective of this study was to investigate these interactions and identify any synergistic combinations. Eleven foods from three categories, including fruits (raspberry, blackberry, and apple), vegetables (broccoli, tomato, mushroom, and purple cauliflower), and legumes (soybean, adzuki bean, red kidney bean, and black bean) were combined in pairs. Four assays (total phenolic content, ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl, radical scavenging capacity, and oxygen radical absorbance capacity) were used to evaluate the antioxidant capacities of individual foods and their combinations. The results indicated that within the same food category, 13, 68, and 21% of the combinations produced synergistic, additive, and antagonistic interactions, respectively, while the combinations produced 21, 54, and 25% synergistic, additive, and antagonistic effects, respectively, across food categories. Combining specific foods across categories (e.g., fruit and legume) was more likely to result in synergistic antioxidant capacity than combinations within a food group. Combining raspberry and adzuki bean extracts demonstrated synergistic interactions in all four chemical-based assays. Compositional changes did not seem to have occurred in the mixture. Results in this study suggest the importance of strategically selecting foods or diets to maximum synergisms as well as to minimum antagonisms in antioxidant activity.

Nuclear translocation of the 1,25D3-MARRS (membrane associated rapid response to steroids) receptor protein and NFkappaB in differentiating NB4 leukemia cells.

1,25 Dihydroxyvitamin D(3) (1,25D(3)) primes NB4 promyelocytic leukemia cells to differentiate along the monocyte/macrophage lineage through a non-genomic mechanism. Here we show that NB4 cells express high levels of the recently identified membrane receptor for 1,25D(3), which is a distinct gene product from the classical nuclear vitamin D receptor. This 57 kDa protein, named 1,25D(3)-MARRS (Membrane Activated Rapid Response to Steroids)/ERp57/PIA3 appears to associate in a complex with the transcription factor, nuclear factor kappa B (NFkappaB). In unstimulated cells, 1,25D(3)-MARRS can be co-immunoprecipitated with antibodies directed at NFkappaB, and NFkappaB is co-precipitated when antibodies against 1,25D(3)-MARRS or ERp57 are used. Confocal microscopy and subcellular fractionation studies demonstrate that both 1,25D(3)-MARRS and NFkappaB begin translocating to the nucleus within minutes of co-stimulation with 1,25D(3) and phorbol ester. The predominant nuclear localization of both proteins precedes the expression of the monocyte/macrophage phenotype and suggests that this event may be critical to the differentiation pathway. This suggests a role for 1,25D(3)-MARRS in the nucleus as a regulator of gene expression. Here it may also regulate the activity of NFkappaB and other factors with which it may be interacting.

Involvement of 1,25D3-MARRS (membrane associated, rapid response steroid-binding), a novel vitamin D receptor, in growth inhibition of breast cancer cells.

In addition to classical roles in calcium homeostasis and bone development, 1,25 dihydroxyvitamin D3 [1,25(OH)2D3] inhibits the growth of several cancer types, including breast cancer. Although cellular effects of 1,25(OH)2D3 traditionally have been attributed to activation of a nuclear vitamin D receptor (VDR), a novel receptor for 1,25(OH)2D3 called 1,25D3-MARRS (membrane-associated, rapid response steroid-binding) protein was identified recently. The purpose of this study was to determine if the level of 1,25D3-MARRS expression modulates 1,25(OH)2D3 activity in breast cancer cells. Relative levels of 1,25D3-MARRS protein in MCF-7, MDA MB 231, and MCF-10A cells were estimated by real-time RT-PCR and Western blotting. To determine if 1,25D3-MARRS receptor was involved in the growth inhibitory effects of 1,25(OH)2D3 in MCF-7 cells, a ribozyme construct designed to knock down 1,25D(3)-MARRS mRNA was stably transfected into MCF-7 cells. MCF-7 clones in which 1,25D3-MARRS receptor expression was reduced showed increased sensitivity to 1,25(OH)2D3 ( IC(50) 56+/-24 nM) compared to controls (319+/-181 nM; P<0.05). Reduction in 1,25D3-MARRS receptor lengthened the doubling time in transfectants treated with 1,25(OH)2D3. Knockdown of 1,25D3-MARRS receptor also increased the sensitivity of MCF-7 cells to the vitamin D analogs KH1060 and MC903, but not to unrelated agents (all-trans retinoic acid, paclitaxel, serum/glucose starvation, or the isoflavone, pomiferin). These results suggest that 1,25D3-MARRS receptor expression interferes with the growth inhibitory activity of 1,25(OH)2D3 in breast cancer cells, possibly through the nuclear VDR. Further research should examine the potential for pharmacological or natural agents that modify 1,25D3-MARRS expression or activity as anticancer agents.

Guanosine acts intracellularly to initiate apoptosis in NB4 cells: A role for nucleoside transport.

Guanosine initiated apoptosis in NB4 cells in a transport-dependent manner. Apoptosis was partially attributed to an imbalance in nucleosides with some protection upon the addition of pyrimidines. The effect of guanosine on cell proliferation and viability was biphasic whereby cells were able to recover from an initial cell cycle arrest and re-enter the cell cycle upon removal of guanosine in a time-dependent fashion. However, exposure to guanosine beyond 24 h prevented recovery and ultimately led to death. Death occurred with a decrease in bcl-2 protein expression, thus suggesting that the pathway to apoptosis involved change(s) in the intracellular environment that were ultimately sensed by the mitochondria. Expression of the unique guanosine-specific nucleoside transporter csg in NB4 cells may provide an opportunity to harness guanosine-mediated cell death in the treatment of APL and related malignancies while sparing normal cells.

A randomized trial of a hypocaloric high-protein diet, with and without exercise, on weight loss, fitness, and markers of the Metabolic Syndrome in overweight and obese women.

The purpose of this study was to examine the effects of 3:1 and 1:1 carbohydrate to protein ratios, hypocaloric diets with and without exercise, and risk factors associated with the Metabolic Syndrome in overweight and obese Canadian women. Groups were designated as control diet (CON), control diet with exercise (CONEx), high-protein (HP), or high-protein with exercise (HPEx). Free-living women from the Guelph community were studied in a university health and fitness facility. The participants were 44 of 60 overweight and obese women who had been randomized to the 4 weight-loss programs. Habitual diets of the subjects were energy restricted and were to contain either a 1:1 or 3:1 ratio of carbohydrate to protein energy. Subjects either exercised 3 times/week or maintained their normal level of activity for 12 weeks. The main outcome measures were weight loss, blood lipids, blood pressure, insulin, body composition, nitrogen balance, fitness, and resting energy expenditure. All groups lost weight over the 12 week period: -2.1 kg for the CON group, -4.0 kg in the CONEx group, -4.6 kg in the HP group, and -7.0 kg in the HPEx. All participants exhibited improved body composition, decreased blood pressure, and decreased waist and hip circumference. Actual diets consumed by the subjects contained ratios of carbohydrate to protein of 3.0:1, 2.7:1, 1.5:1, and 0.96:1 for the CON, CONEx, HP, and HPEx groups, respectively. Cardiovascular fitness improved in both exercise groups. There were no changes in resting energy expenditure. No adverse events were reported. Significant changes in blood lipids included decreased total cholesterol in the HP and CONEx groups, decreased low-density lipoprotein cholesterol in the HP group only, and decreased blood triglycerides in the HPEx group only. High-density lipoprotein cholesterol, fasting blood glucose, and fasting insulin levels were unaltered by diet or exercise. A high-protein diet was superior to a low-fat, high-carbohydrate diet either alone or when combined with an aerobic/resistance-training program in promoting weight loss and nitrogen balance, while similarly improving body composition and risk factors for the Metabolic Syndrome in overweight and obese Canadian women.

Nucleoside transporter expression and activity is regulated during granulocytic differentiation of NB4 cells in response to all-trans-retinoic acid.

NB4 cells express multiple nucleoside transporters (NTs), including: hENT1 (es), and hENT2 (ei), and the CNT subtype referred to as, csg; a concentrative sensitive guanosine specific transporter. csg activity is a distinguishing feature of the NB4 cell line and its presence suggests a particular requirement of these cells for guanosine salvage. Proliferation and differentiation pathways determine, in part, the number of NTs in cells and tissues. In this study, all-trans-retinoic acid (ATRA)-induced granulocytic differentiation of NB4 cells resulted in biphasic changes in guanosine transport. Transient increases in csg and es activity, the result of an increase in V(max) (pmol/muls) of both transporter systems, served as early markers of differentiation while expression of a fully differentiated phenotype was accompanied by a selective loss of csg activity and the return of es activity to that of proliferating cells. Intracellular incorporation of [(3)H]-guanosine decreased as cells matured despite increased transport rates and suggested a reduced intracellular requirement of NB4-granulocytes compared to their proliferating counterparts. Whether a loss of csg activity could serve to assess clinical response to differentiation therapies is not known. Nitrobenzylthioinosine (NBMPR) binding sites within nuclear membrane (NM) preparations, suggested the presence of functional intracellular NTs. An increase in plasma membrane (PM) associated transporters coincided with the early increase in guanosine transport and a decrease in NBMPR binding to NM fractions and suggests that intracellular NTs may serve as a reserve pool for translocation to the (PM) when additional transport capacity is required. The modulation of transporters during differentiation could potentially regulate drug bioavailability and cytotoxicity and should be evaluated prior to combining differentiating agents with traditional nucleoside analogs in the treatment of APL.

Vitamin status and cognitive function in a long-term care population.

BACKGROUND: Ageing can be associated with poor dietary intake, reduced nutrient absorption, and less efficient utilization of nutrients. Loss of memory and related cognitive function are also common among older persons. This study aimed to measure the prevalence of inadequate vitamin status among long-term care patients and determine if an association exists between vitamin status and each of three variables; cognitive function, vitamin supplementation, and medications which alter gastric acid levels. METHODS: Seventy-five patients in a long-term care hospital in Guelph, Ontario were recruited to a cross-sectional study. 47 were female and the mean age was 80.7 (+/-11.5) years, ranging from 48 to 100 years. Blood was used to measure levels of vitamins B12 (cobalamin), B6 (pyridoxal-5'-phosphate/PLP), erythrocyte folate, vitamin B3 (niacin) and homocysteine (Hcy). The Standardized Mini-Mental State Examination (SMMSE) was administered to measure cognitive function. A list of medications and vitamin supplementation for each patient was provided by the pharmacy. RESULTS: The prevalence of low vitamin (B12, B6, erythrocyte folate, niacin) or high metabolite (homocysteine) levels among 75 patients were as follows: B12 <148 pmol/L in 5/75 (6.7%); B12 between 148 and 221 pmol/L in 26/75 (34.7%); B6 13.3 micromol/L in 31/75 (41.3%). There was no significant difference among residents grouped into marked (n = 44), mild (n = 14), or normal (n = 9) cognitive function when evaluating the effect of vitamin status. There were no significant differences in mean B12 and homocysteine levels between users and non-users of drug therapy (Losec, Zantac, or Axid). Compared to vitamin supplement non-users, supplemented residents had significantly higher mean B12 (p < 0.0001) and erythrocyte folate (p < 0.05) concentrations and significantly lower mean homocysteine (p < 0.01) levels; 229.1 versus 423.6 pmol/L for B12, 882.9 versus 1043.6 nmol/L for erythrocyte folate and 14.4 versus 12.0 micromol/L for homocysteine. CONCLUSION: Given the prevalence data on vitamin status in this sample population, the possible benefits of vitamin supplementation should be considered in clinical intervention studies using these populations of elderly.

Low dose docosahexaenoic acid protects normal colonic epithelial cells from araC toxicity.

BACKGROUND: The nucleoside analogue arabinosylcytosine (araC) has been used for many years in the treatment of acute leukemia. Evidence in the literature suggests that araC may inhibit the growth of human colon carcinoma cell lines as well. Because araC action interferes with normal nucleoside metabolism, it is highly toxic to a number of normal cell types including bone marrow and intestinal mucosa cells. Here we investigate whether the omega-3 fatty acid docosahexaenoic acid (DHA) could selectively target araC toxicity toward colonic tumor cells while protecting the normal cells in vitro. RESULTS: Cultures of normal rat colonic epithelial cells (4D/WT) and those transformed by v-src (D/v-src) were supplemented with graded concentrations of DHA or arachidonic acid (AA) alone or in combination with araC. AraC was only 1.6 fold more toxic to D/v-src than 4D/WT in cultures without added fatty acids. Supplementing with as little as 3 muM of either AA or DHA increased araC toxicity by more than 30-fold in the tumorigenic cells. The toxic effect of araC on the normal cells was also increased by the fatty acid supplementation. IC50 values were decreased 1.7 fold by DHA in the 4D/WT cells but a more than 7-fold decrease was observed during AA supplementation. As a result, the therapeutic index of araC (IC50 normal/IC50 tumor) was more than 3-fold higher in the DHA than the AA supplemented cells. The expression of protein kinase C isoform epsilon was decreased in AA alone supplemented D/v-src cultures but in combination with araC decreased only in DHA supplemented 4D/WT cells. CONCLUSION: Low dose DHA supplementation may enhance araC chemotherapy in colon cancer while protecting normal tissues, possibly through control of PKC signalling pathways.

Fatty acids and exercise affect glucose transport but not tumour growth in F-344 rats.

This study examined the effect of diet and exercise on tumour growth, and the effect of dietary fatty acids on glucose uptake. Male Fischer 344 rats were divided into 4 dietary groups and fed for 2 weeks. The diets were 5% (wt/wt) safflower oil, 10% safflower oil, 5% docosahexaenoic acid(DHA)-rich, and 10% DHA-rich. On Day 14 the animals were injected with rat fibrosarcoma tumour cells. After 3 days of tumour growth the animals in each diet group were divided into exercise and nonexercise groups. Exercise was achieved by voluntary wheel running. Dietary intake, body weight, tumour growth, and distance run were determined daily. Two weeks later the animals were euthanized and the following tissues were dissected out: tumour, liver, heart, epididymal fat pads, gastrocnemius, epitrochlearis, and soleus muscles. Glucose transport experiments were performed on the epitrochlearis and soleus muscles whereas phospholipid analysis was completed on the gastrocnemius muscle. We observed no effect of either diet or exercise on tumour growth. The glucose transport data demonstrates that short-term voluntary running can cause increased insulin-sensitive transport and that DHA may inhibit transport. DHA-containing diets were associated with increased oxidation products TBARM. In conclusion, exercise benefits on glucose disposal are maintained in tumour-bearing animals but are influenced by fat content and composition. High DHA diets may also increase oxidative damage in muscle through enhanced TBARM production.

Comparison of a low-fat diet to a low-carbohydrate diet on weight loss, body composition, and risk factors for diabetes and cardiovascular disease in free-living, overweight men and women.

Overweight and obese men and women (24-61 yr of age) were recruited into a randomized trial to compare the effects of a low-fat (LF) vs. a low-carbohydrate (LC) diet on weight loss. Thirty-one subjects completed all 10 wk of the diet intervention (retention, 78%). Subjects on the LF diet consumed an average of 17.8% of energy from fat, compared with their habitual intake of 36.4%, and had a resulting energy restriction of 2540 kJ/d. Subjects on the LC diet consumed an average of 15.4% carbohydrate, compared with habitual intakes of about 50% carbohydrate, and had a resulting energy restriction of 3195 kJ/d. Both groups of subjects had significant weight loss over the 10 wk of diet intervention and nearly identical improvements in body weight and fat mass. LF subjects lost an average of 6.8 kg and had a decrease in body mass index of 2.2 kg/m2, compared with a loss of 7.0 kg and decrease in body mass index of 2.1 kg/m2 in the LC subjects. The LF group better preserved lean body mass when compared with the LC group; however, only the LC group had a significant decrease in circulating insulin concentrations. Group results indicated that the diets were equally effective in reducing systolic blood pressure by about 10 mm Hg and diastolic pressure by 5 mm Hg and decreasing plasminogen activator inhibitor-1 bioactivity. Blood beta-hydroxybutyrate concentrations were increased in the LC only, at the 2- and 4-wk time points. These data suggest that energy restriction achieved by a very LC diet is equally effective as a LF diet strategy for weight loss and decreasing body fat in overweight and obese adults.

1alpha,25-dihydroxyvitamin D3 and bryostatin-1 synergize to induce monocytic differentiation of NB4 acute promyelocytic leukemia cells by modulating cell cycle progression.

This study examines the role of 1alpha,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) and the natural compound, bryostatin-1, on the monocytic differentiation of NB4 acute promyelocytic leukemia cells. We previously showed that 1,25(OH)(2)D(3) primes NB4 cells to mature along the monocyte/macrophage pathway in response to the tumor-promoting phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). This maturation response involves protein kinase C (PKC) signaling, activation of the transcription factor nuclear factor kappaB (NFkB), and intracellular calcium and calpain activity. The natural compound, bryostatin-1, exhibits some of the effects of TPA but lacks its tumor-promoting nature. 1,25(OH)(2)D(3) treatment followed by bryostatin-1 induces monocytic differentiation of NB4 cells, however,this effect is less pronounced than the combination of 1,25(OH)(2)D(3) and TPA. Maturation is accompanied by decreased proliferation, changes in cellular morphology, increased plastic adherence, and expression of the cell surface marker CD14. Changes in the cell cycle traverse occur before the morphological and biochemical changes associated with differentiation. Within 24 h of bryostatin-1 addition, NB4 cells begin arresting, predominantly in G(1) phase. Changes in the cell cycle traverse were accompanied by changes in the expression of several cell cycle regulatory proteins. Combination 1,25(OH)(2)D(3) and bryostatin-1 treatment, resulted in decreased expression of the cyclin-dependent kinases Cdk2, Cdk1, and Cdk4, of cyclins E and D3, and of the retinoblastoma binding protein (RBBP). Levels of the cyclin-dependent kinase inhibitors p21 and p27 as well as Cyclin D1 were undetectable in NB4 cell lysates, suggesting that they do not participate in the differentiation response or cell cycle control in this model.