Effects of Chromium Picolinate on Micronucleus Frequency and Morphology of Lymphocytes in Calves

We report the effects of chromium picolinate (CrPic) on micronucleus frequency, morphology of lymphocytes, and lipid peroxidation in calves. Twenty-four Holstein calves were selected for the study. They were kept in a farm and were fed a commercially available calf diet and alfalfa, ad libitum. The animals were divided into three groups of eight subjects each and were treated as follows: The first group was supplemented with a daily dose of 200 μg Cr as chromium picolinate; a second group received 400 μg Cr per day and a third group that served as control received no supplemental chromium. After 12-week supplementation, blood samples were collected to determine the micronucleus frequency, the apoptotic cell percentage, and the malondialdehyde (MDA) and blood chromium levels. In both supplemented groups, the cells had irregularly shaped and segmented nuclei. Supplementation also increased the percentage of apoptotic cells (p < 0.001) and serum MDA (p < 0.01) and slightly increased the chromium levels. The animals supplemented with 400 μg showed a significant increase of micronucleus frequency (p < 0.01). The results of this study suggest that supplementation with 200 and 400 μg chromium as chromium picolinate may lead to cytotoxicity. The higher level of supplementation may also have genotoxic effects. However, further studies investigating the mechanism of the action of CrPic are required.     

Knottin cyclization: impact on structure and dynamics

Background  

Present in various species, the knottins (also referred to as inhibitor cystine knots) constitute a group of extremely stable miniproteins with a plethora of biological activities. Owing to their small size and their high stability, knottins are considered as excellent leads or scaffolds in drug design. Two knottin families contain macrocyclic compounds, namely the cyclotides and the squash inhibitors. The cyclotide family nearly exclusively contains head-to-tail cyclized members. On the other hand, the squash family predominantly contains linear members. Head-to-tail cyclization is intuitively expected to improve bioactivities by increasing stability and lowering flexibility as well as sensitivity to proteolytic attack.     

Ketogenic Diet Impairs FGF21 Signaling and Promotes Differential Inflammatory Responses in the Liver and White Adipose Tissue

Background/HypothesisBeside its beneficial effects on weight loss, ketogenic diet (KD) causes dyslipidemia, a pro-inflammatory state involved in the development of hepatic steatosis, glucose intolerance and insulin resistance, although the latter is still being debated. Additionally, KD is known to increase fibroblast growth factor 21 (FGF21) plasma levels. However, FGF21 cannot initiate its beneficial actions on metabolism in these conditions. We therefore hypothesized and tested in the present study that KD may impair FGF21 signaling.Methods/ResultsUsing indirect calorimetry, we found that KD-fed mice exhibited higher energy expenditure than regular chow (RC)-fed mice associated with increased Ucp1 levels in white adipose tissue (WAT), along with increased plasma FGF21 levels. We then assessed the effect of KD on FGF21 signaling in both the liver and WAT. We found that Fgfr4 and Klb (β-klotho) were downregulated in the liver, while Fgfr1 was downregulated in WAT of KD-fed mice. Because inflammation could be one of the mechanisms linking KD to impaired FGF21 signaling, we measured the expression levels of inflammatory markers and macrophage accumulation in WAT and liver and found an increased inflammation and macrophage accumulation in the liver, but surprisingly, a reduction of inflammation in WAT.We also showed that KD enhances lipid accumulation in the liver, which may explain hepatic inflammation and impaired Fgfr4 and Klb expression. In contrast, import of lipids from the circulation was significantly reduced in WAT of KD-fed mice, as suggested by a downregulation of Lpl and Cd36. This was further associated with reduced inflammation in WAT.ConclusionAltogether, these results indicate that KD could be beneficial for a given tissue but deleterious for another.     

Improved absorption of caseinophosphopeptide-bound iron: role of alkaline phosphatase

Hydrolysis of proteins could lessen their inhibiting effect on the poor absorption of cow's milk iron (Fe), which is responsible for the high incidence of Fe deficiency worldwide. When bound to Fe, caseinophosphopeptides (CPP) derived from milk proteins resist luminal digestion, enhance Fe solubility and could improve its bioavailability; brush border enzyme alkaline phosphatase activity could influence iron absorption by releasing free Fe; this study assessed its role in the absorption of CPP-bound Fe. Rat duodenal loops were perfused with Fe gluconate or Fe bound to the CPP of beta casein [beta-CN (1-25)], with or without the addition of an inhibitor of alkaline phosphatase, Na2WO4. The uptake of Fe-beta-CN (1-25) was greater than Fe gluconate. Na2WO4 enhanced the uptake of Fe-beta-CN (1-25) and not of Fe gluconate. So the release of free, insoluble Fe, by alkaline phosphatase seems to be prevented by providing Fe in the Fe-beta-CN (1-25) complex form. Its good disappearance rate makes beta-CN (1-25)-bound Fe a candidate for food fortification.     

The protective effect of licofelone on experimental osteoarthritis is correlated with the downregulation of gene expression and protein synthesis of several major cartilage catabolic factors: MMP-13, cathepsin K and aggrecanases

This study sought to evaluate the levels of mRNA expression and protein synthesis of MMP-13, cathepsin K, aggrecanase-1 (ADAMTS-4), aggrecanase-2 (ADAMTS-5) and 5-lipoxygenase (5-LOX) in cartilage in the experimental anterior cruciate ligament (ACL) dog model of osteoarthritis (OA), and to examine the effects of treatment with licofelone, a 5-lipoxygenase (LOX)/cyclooxygenase (COX) inhibitor, on the levels of these catabolic factors. Sectioning of the ACL of the right knee was performed in three experimental groups: group 1 received no active treatment (placebo group); and groups 2 and 3 received therapeutic concentrations of licofelone (2.5 or 5.0 mg/kg/day orally, respectively) for 8 weeks, beginning the day following surgery. A fourth group consisted of untreated dogs that were used as normal controls. Specimens of cartilage were selected from lesional areas of OA femoral condyles and tibial plateaus, and were processed for real-time quantitative PCR and immunohistochemical analyses. The levels of MMP-13, cathepsin K, ADAMTS-4, ADAMTS-5 and 5-LOX were found to be significantly increased in OA cartilage. Licofelone treatment decreased the levels of both mRNA expression and protein synthesis of the factors studied. Of note was the marked reduction in the level of 5-LOX gene expression. The effects of the drug were about the same at both tested dosages. In vivo treatment with therapeutic dosages of licofelone has been found to reduce the degradation of OA cartilage in experimental OA. This, coupled with the results of the present study, indicates that the effects of licofelone are mediated by the inhibition of the major cartilage catabolic pathways involved in the destruction of cartilage matrix macromolecules. Moreover, our findings also indicate the possible auto-regulation of 5-LOX gene expression by licofelone in OA cartilage.