Paddy L. Wiesenfeld

Nutritional and hematological impact of dietary flaxseed and defatted flaxseed meal in rats

An 8-week study was conducted to determine the impact of dietary ground flaxseed (FS) or defatted flaxseed meal (FLM) on plasma lipids, minerals, hematological parameters and vitamin E status of weanling female Sprague-Dawley rats. These rats were fed isocaloric modified AIN-76 diets supplemented with 0.0, 5.0, 10.0% (w/w) FS or 6.2% (w/w) FLM for 56 days. Total and HDL cholesterol were not influenced by any of the dietary treatments. Plasma triglyceride was significantly increased by FLM, but not affected by FS. Total RBC counts and hematocrit were significantly higher in FS groups than in the control group; however, hemoglobin was not affected by FS. Dietary FLM had no effect on any of the above hematological parameters. Plasma alkaline phosphatase, an indicator of Zn status and a marker of bone formation, was significantly lower in the FS and FLM groups than in the control group. Plasma vitamin E content was not influenced by dietary treatment. Liver vitamin E was significantly higher in groups fed 10% FS and 6.2% FLM. In summary, moderate amounts of dietary FS may have the potential to increase liver vitamin E level and improve iron status. However, FS/FLM consumption may have a negative effect on zinc status, as indicated by decreased alkaline phosphatase levels.An 8-week study was conducted to determine the impact of dietary ground flaxseed (FS) or defatted flaxseed meal (FLM) on plasma lipids, minerals, hematological parameters and vitamin E status of weanling female Sprague-Dawley rats. These rats were fed isocaloric modified AIN-76 diets supplemented with 0.0, 5.0, 10.0% (w/w) FS or 6.2% (w/w) FLM for 56 days. Total and HDL cholesterol were not influenced by any of the dietary treatments. Plasma triglyceride was significantly increased by FLM, but not affected by FS. Total RBC counts and hematocrit were significantly higher in FS groups than in the control group; however, hemoglobin was not affected by FS. Dietary FLM had no effect on any of the above hematological parameters. Plasma alkaline phosphatase, an indicator of Zn status and a marker of bone formation, was significantly lower in the FS and FLM groups than in the control group. Plasma vitamin E content was not influenced by dietary treatment. Liver vitamin E was significantly higher in groups fed 10% FS and 6.2% FLM. In summary, moderate amounts of dietary FS may have the potential to increase liver vitamin E level and improve iron status. However, FS/FLM consumption may have a negative effect on zinc status, as indicated by decreased alkaline phosphatase levels.

Web-Enabled and Improved Software Tools and Data Are Needed to Measure Nutrient Intakes and Physical Activity for Personalized Health Research

Food intake, physical activity (PA), and genetic makeup each affect health and each factor influences the impact of the other 2 factors. Nutrigenomics describes interactions between genes and environment. Knowledge about the interplay between environment and genetics would be improved if experimental designs included measures of nutrient intake and PA. Lack of familiarity about how to analyze environmental variables and ease of access to tools and measurement instruments are 2 deterrents to these combined studies. This article describes the state of the art for measuring food intake and PA to encourage researchers to make their tools better known and more available to workers in other fields. Information presented was discussed during a workshop on this topic sponsored by the USDA, NIH, and FDA in the spring of 2009.

In vitro toxicity screening of chemical mixtures using HepG2/C3A cells

Traditional toxicological methods that utilize only single pure compounds may not accurately predict risks from substances with multiple chemical constituents. A complementary approach to conventional methodologies includes in vitro systems that assess toxicity of chemical mixtures and identify components that may adversely impact biological processes. Compared to animal models, in vitro assays are inexpensive, rapid, and reduce and refine related animal testing. We utilized HepG2/C3A cells as a hepatotoxicity screening model to evaluate the cytotoxic and metabolic effects of three commercially available oil dispersants, Corexit EC9500A and EC9527A and ZI-400. The surfactant DOSS, a primary active constituent of the Corexit dispersants, was also evaluated. Biologically relevant endpoints were measured including cell viability, oxidative stress, and mitochondrial activity. Significant increases in cytotoxicity were observed with Corexit dispersants (LC(50)∼250 ppm), whereas ZI-400 was moderately cytotoxic (LC(50) >>400 ppm). Each dispersant caused an accumulation of reactive oxygen species and altered mitochondrial activity and other cellular processes. Generally, DOSS made notable contributions to the effects of EC9500A and EC9527A, however, they were observed at concentrations higher than those used in most consumer products. Overall, this system may represent a valuable complementary tool for predicting the toxicity of complex mixtures.

Effect of dietary flaxseed on fatty acid composition, superoxide, nitric oxide generation and antilisterial activity of peritoneal macrophages from female Sprague-Dawley rats.

The impact of ground flaxseed (FS) or flaxseed meal (FSM) diets on the fatty acid composition and functions of rat peritoneal exudate cells (PEC) was determined. Female weanling Sprague-Dawley rats (10/group) were fed isocaloric AIN-76 diets supplemented with 0.0, 10.0% (w/w) FS or 6.2% (w/w) FSM. At the end of 56-days, rat serum and thioglycollate-elicited PEC were analyzed for total lipid fatty acids. Production of nitric oxide (NO) and superoxide (O2-), Listeria monocytogenes (LM) phagocytic index and antilisterial activity of resident PEC were also assessed. A significant increase in alpha-linolenic (C18:3), eicosapentanoic (C20:5) and docosahexanoic (C22:6) acids, as well as a significant reduction in arachidonic acid (C20:4) was observed in the serum of rats fed 10% FS. Dietary FS caused a significant reduction in palmitic acid (C16:0) and an increase in stearic acid (C18:0) of PEC. Defatted FSM produced a significant increase in long chain fatty acids, which included eicosadienoic acid (C20:2) in PEC and C22:6 in serum. PEC from rats fed 10.0% FS produced significantly less (about 50%) O2- in response to phorbol myristate acetate (PMA), than did PEC from control animals; dietary treatment had no effect on O2- in response to LM. FSM had no impact on the O2- production by PEC in response to PMA or LM. Antilisterial activity of PEC was determined by comparing bacterial uptake after 1 hr with recovery 24 hrs later. Despite comparably equivalent bacterial uptake, few viable intracellular LM were recovered at T = 24 for all test samples, indicating that, regardless of the dietary treatment, PEC were able to handle the in vitro LM infection. This bacterial clearance was accompanied by equivalent NO generation by PEC from each dietary group in response to LM. Summarily, dietary FS produced significant changes in fatty acid composition of serum and PEC, inhibited O2- generation by PEC, and was ineffectual to both NO production by and antilisterial activity of PEC.

Comparative hepatotoxicity of deoxynivalenol in rat, mouse and human liver cells in culture.

The present study was undertaken to assess, in vitro, the hepatotoxic potential of the food‐borne mycotoxin, deoxynivalenol (DON), using rat (Clone9 and MH1C1), mouse (NBL CL2) and human (WRL68 and HepG2) liver cells in culture. The cells were treated with DON for 24 h at 37 °C in 5% CO2 at concentrations of 0–25 µg ml−1. Following the treatment period, the cells were assayed for biochemical markers of hepatotoxicity that included three independent cytotoxicity assays, oxidative stress and mitochondrial dysfunction. Concentration‐dependent cytotoxicity of DON was observed in each of the five different liver cells derived from three different species (rat, mouse and human) over the entire concentration range studied, beginning at 0.1 µg ml−1. At these concentrations DON did not induce a biologically significant increase in oxidative stress in these liver cells, and showed a significant decrease in the mitochondrial function only in the rat liver MH1C1 cells compared with the control. The results of this in vitro study suggest that DON is a potential hepatotoxin for the rat, mouse and human liver cells in the concentration range tested in this study. The liver cells used in this study showed distinct endpoint‐sensitivity to DON related to the species. Published in 2010 by John Wiley and Sons, Ltd.

Inhibition of monoamine oxidase (MAO) by β-carbolines and their interactions in live neuronal (PC12) and liver (HuH-7 and MH1C1) cells.

Interactions among monoamine oxidase (MAO) inhibitors in drugs, botanicals, and dietary supplements may lead to unpredictable neurochemical dysfunction due to excessive inhibition or therapeutic invalidation. Often recombinant MAO or brain tissue homogenates have been used to evaluate MAO inhibitors such as the β-carboline alkaloids (harmane, harmine, harmaline, and harmalol). However, there is a lack of cellular systems for evaluation of MAO activity, which represents a more advanced in vitro model compared to recombinant enzymes or tissue lysates. Using kynuramine assays, intracellular MAO inhibition by β-carbolines was measured in PC12 (rat pheochromocytoma), MH1C1 (rat liver), and HuH-7 (human liver) cell lines, which were compared with human recombinant MAO and cell lysates. β-Carbolines (1 μM, 90 min incubations) inhibited MAO by 40-99% in live PC12 cells where MAO A was the active isoform, and <12% in HuH-7 and MH1C1 cells where MAO B was primarily active. The combination index (CI), which serves as a quantitative indicator of pharmacological interactions, was determined for harmaline/harmine (CI, 1.01-1.25) and methylene blue/harmine (CI, 0.74-1.07) in PC12 cells. Overall, this study illustrates applications of cell-based in vitro assay platforms to gain a comprehensive understanding of intracellular MAO inhibitors and their interactions.

TGFβ1 alters androgenic metabolites and hydroxysteroid dehydrogenase enzyme expression in human prostate reactive stromal primary cells: Is steroid metabolism altered by prostate reactive stromal microenvironment?

The inflammatory tissue microenvironment can be an active promoter in preneoplastic cancer lesions. Altered steroid hormone metabolism as induced by the inflammatory microenvironment may contribute to epithelial cancer progression. Dehydroepiandrosterone sulfate (DHEAS) is the most abundant endogenous steroid hormone present in human serum and can be metabolized to DHEA, androgens and/or estrogens in peripheral tissues. We have previously reported that TGFβ1-induced reactive prostate stromal cells increase DHEA metabolism to active androgens and alter prostate cancer cell gene expression. While much of the focus on mechanisms of prostate cancer and steroid metabolism is in the epithelial cancer cells, this study focuses on TGFβ1-induced effects on DHEA metabolic pathways and enzymes in human prostate stromal cells. In DHEA-treated primary prostate stromal cells, TGFβ1 produced time- and dose-dependent increases in metabolism of DHEA to androstenedione and testosterone. Also TGFβ1-treated prostate stromal cells exhibited changes in the gene expression of enzymes involved in steroid metabolism including up-regulation of 3β hydroxysteroid dehydrogenase (HSD), and down-regulation of 17βHSD5, and 17βHSD2. These studies suggest that reactive prostate stroma and the inflammatory microenvironment may contribute to altered steroid metabolism and increased intratumoral androgens.

A beating heart cell model to predict cardiotoxicity: effects of the dietary supplement ingredients higenamine, phenylethylamine, ephedrine and caffeine.

Some dietary supplements may contain cardiac stimulants and potential cardiotoxins. In vitro studies may identify ingredients of concern. A beating human cardiomyocyte cell line was used to evaluate cellular effects following phenylethylamine (PEA), higenamine, ephedrine or caffeine treatment. PEA and higenamine exposure levels simulated published blood levels in humans or animals after intravenous administration. Ephedrine and caffeine levels approximated published blood levels following human oral intake. At low or midrange levels, each chemical was examined plus or minus 50 µM caffeine, simulating human blood levels reported after consumption of caffeine-enriched dietary supplements. To measure beats per minute (BPM), peak width, etc., rhythmic rise and fall in intracellular calcium levels following 30 min of treatment was examined. Higenamine 31.3 ng/ml or 313 ng/ml significantly increased BPM in an escalating manner. PEA increased BPM at 0.8 and 8 µg/ml, while 80 µg/ml PEA reduced BPM and widened peaks. Ephedrine produced a significant BPM dose response from 0.5 to 5.0 µM. Caffeine increased BPM only at a toxic level of 250 µM. Adding caffeine to PEA or higenamine but not ephedrine further increased BPM. These in vitro results suggest that additional testing may be warranted in vivo to further evaluate these effects.

Evaluation of “Dream Herb,” Calea zacatechichi, for Nephrotoxicity Using Human Kidney Proximal Tubule Cells

A recent surge in the use of dietary supplements, including herbal remedies, necessitates investigations into their safety profiles. “Dream herb,” Calea zacatechichi, has long been used in traditional folk medicine for a variety of purposes and is currently being marketed in the US for medicinal purposes, including diabetes treatment. Despite the inherent vulnerability of the renal system to xenobiotic toxicity, there is a lack of safety studies on the nephrotoxic potential of this herb. Additionally, the high frequency of diabetes-associated kidney disease makes safety screening of C. zacatechichi for safety especially important. We exposed human proximal tubule HK-2 cells to increasing doses of this herb alongside known toxicant and protectant control compounds to examine potential toxicity effects of C. zacatechichi relative to control compounds. We evaluated both cellular and mitochondrial functional changes related to toxicity of this dietary supplement and found that even at low doses evidence of cellular toxicity was significant. Moreover, these findings correlated with significantly elevated levels of nephrotoxicity biomarkers, lending further support for the need to further scrutinize the safety of this herbal dietary supplement.

Cardiotoxicity testing of diglycolic acid using In Vitro and In Vivo models

Abstract Background: Renal and hepatotoxicity of diglycolic acid (DGA) has been described with in vitro cellular models as well as in vivo animal and human systems. The possibility of DGA being toxic