Association of COL5A1 gene polymorphisms and risk of tendon-ligament injuries among Caucasians: a meta-analysis

Abstract Background Tendons and ligaments are common sites of musculoskeletal injuries especially during physical activity. The multifactorial etiology of tendon-ligament injury (TLI) includes both genetic and environmental factors. The genetic component could render influence on TLI risk to be either elevation or reduction. Objective Inconsistency of reported associations of the collagen type V alpha 1 chain (COL5A1) polymorphisms, mainly rs12722 (BstUI) and rs13946 (DpnII), with TLI warrant a meta-analysis to determine more precise pooled associations. Methods Multi-database literature search yielded eight articles (11 studies) for inclusion. Pooled odds ratios (ORs) and 95% confidence intervals were used to estimate associations. Heterogeneity of outcomes warranted examining their sources with outlier treatment. Results All rs12722 effects indicated reduced risk (OR  0.10). The non-significant and heterogeneous (ORs 0.63–0.98, p = 0.13–0.95; up to I 2 = 86%) pre-outlier rs12722 and rs13946 results became significant (ORs 0.32–0.78, p = 10−5−0.01) and heterogeneity eliminated (I 2 = 0%) with outlier treatment. Significant associations (ORs 0.26–0.65, p = 0.002–0.03) were also observed in other COL5A1 polymorphisms (rs71746744 and rs16399). Sensitivity analysis deemed all significant outcomes to be robust. Conclusions In summary, COL5A1 polymorphisms reduce the risk of TLI among Caucasians. These findings are based on the evidence of significance, homogeneity, consistency, and robustness. Additional studies are warranted to draw more comprehensive conclusions

Fructose-induced increases in expression of intestinal fructolytic and gluconeogenic genes are regulated by GLUT5 and KHK.

Marked increases in fructose consumption have been tightly linked to metabolic diseases. One-third of ingested fructose is metabolized in the small intestine, but the underlying mechanisms regulating expression of fructose-metabolizing enzymes are not known. We used genetic mouse models to test the hypothesis that fructose absorption via glucose transporter protein, member 5 (GLUT5), metabolism via ketohexokinase (KHK), as well as GLUT5 trafficking to the apical membrane via the Ras-related protein in brain 11a (Rab11a)-dependent endosomes are required for the regulation of intestinal fructolytic and gluconeogenic enzymes. Fructose feeding increased the intestinal mRNA and protein expression of these enzymes in the small intestine of adult wild-type (WT) mice compared with those gavage fed with lysine or glucose. Fructose did not increase expression of these enzymes in the GLUT5 knockout (KO) mice. Blocking intracellular fructose metabolism by KHK ablation also prevented fructose-induced upregulation. Glycolytic hexokinase I expression was similar between WT and GLUT5- or KHK-KO mice and did not vary with feeding solution. Gavage feeding with the fructose-specific metabolite glyceraldehyde did not increase enzyme expression, suggesting that signaling occurs before the hydrolysis of fructose to three-carbon compounds. Impeding GLUT5 trafficking to the apical membrane using intestinal epithelial cell-specific Rab11a-KO mice impaired fructose-induced upregulation. KHK expression was uniformly distributed along the villus but was localized mainly in the basal region of the cytosol of enterocytes. The feedforward upregulation of fructolytic and gluconeogenic enzymes specifically requires GLUT5 and KHK and may proactively enhance the intestine's ability to process anticipated increases in dietary fructose concentrations

Acute interactions between intestinal sugar and calcium transport in vitro

Fructose consumption by Americans has increased markedly, whereas Ca(2+) intake has decreased below recommended levels. Because fructose metabolism decreases enterocyte ATP concentrations, we tested the hypothesis that luminal fructose acutely reduces active, diet-inducible Ca(2+) transport in the small intestine. We confirmed that the decrease in ATP concentrations was indeed greater in fructose- compared with glucose-incubated mucosal homogenates from wild-type and was prevented in fructose-incubated homogenates from ketohexokinase (KHK)(-/-) mice. We then induced active Ca(2+) transport by chronically feeding wild-type, fructose transporter glucose transporter 5 (GLUT5)(-/-), as well as KHK(-/-) mice a low Ca(2+) diet and measured transepithelial Ca(2+) transport in everted duodenal sacs incubated in solutions containing glucose, fructose, or their nonmetabolizable analogs. The diet-induced increase in active Ca(2+) transport was proportional to dramatic increases in expression of the Ca(2+)-selective channel transient receptor potential vanilloid family calcium channel 6 as well as of the Ca(2+)-binding protein 9k (CaBP9k) but not that of the voltage-dependent L-type channel Ca(v)1.3. Crypt-villus distribution of CaBP9k seems heterogeneous, but low Ca(2+) diets induce expression in more cells. In contrast, KHK distribution is homogeneous, suggesting that fructose metabolism can occur in all enterocytes. Diet-induced Ca(2+) transport was not enhanced by addition of the enterocyte fuel glutamine and was always greater in sacs of wild-type, GLUT5(-/-), and KHK(-/-) mice incubated with fructose or nonmetabolizable sugars than those incubated with glucose. Thus duodenal Ca(2+) transport is not affected by fructose and enterocyte ATP concentrations but instead may decrease with glucose metabolism, as Ca(2+) transport remains high with 3-O-methylglucose that is also transported by sodium-glucose cotransporter 1 but cannot be metabolized

Electrode surfaces based on multiwall carbon nanotubes-chitosan composites validated in the detection of homocysteine biomarkers for cardiovascular disease risk monitoring

This study aimed to modify screen-printed carbon micro-electrode surfaces by coating them with multiwall carbon-based nanotubes conjugated with chitosan and then validated the formed multiwall carbon-based nanotubes-chitosan coated screen printed carbon micro-electrode for the detection of homocysteine, a biomarker analyte known as a risk indicator in cardiovascular disease. The microstructure surface and crystallographic structure stability of the formed multiwall carbon-based nanotubes-chitosan obtained at formed multiwall carbon-based nanotubes per chitosan ratios of 1:1, 2:1, 3:1, and 4:1 were examined via field emission scanning electron microscopy, X-ray radiation, Raman spectroscopy, surface area and pore size, and thermogravimetric analyses. Homocysteine solutions at 30–100 µM were measured by cyclic voltammetry using the different formed multiwall carbon-based nanotubes-chitosan compositions as sensor electrodes. That with an optimal formed multiwall carbon-based nanotubes per chitosan ratio of 4:1 showed the highest crystallinity and electrical conductivity and gave a high coefficient of determination (R2 = 0.9036) between the homocysteine concentration and the oxidation current detection over an operating range of 30–100 µM. This new composite microelectrode for detecting homocysteine concentration makes it a promising candidate for clinical applications

Chronic High Fructose Intake Reduces Serum 1,25 (OH)2D-3 Levels in Calcium-Sufficient Rodents

Excessive fructose consumption inhibits adaptive increases in intestinal Ca2+ transport in lactating and weanling rats with increased Ca2+ requirements by preventing the increase in serum levels of 1,25(OH)(2)D-3. Here we tested the hypothesis that chronic fructose intake decreases 1,25(OH)(2)D-3 levels independent of increases in Ca2+ requirements. Adult mice fed for five wk a high glucose-low Ca2+ diet displayed expected compensatory increases in intestinal and renal Ca2+ transporter expression and activity, in renal CYP27B1 (coding for 1 alpha-hydroxylase) expression as well as in serum 1,25(OH)(2)D-3 levels, compared with mice fed isocaloric glucose- or fructose-normal Ca2+ diets. Replacing glucose with fructose prevented these increases in Ca2+ transporter, CYP27B1, and 1,25(OH)(2)D-3 levels induced by a low Ca2+ diet. In adult mice fed for three mo a normal Ca2+ diet, renal expression of CYP27B1 and of CYP24A1 (24-hydroxylase) decreased and increased, respectively, when the carbohydrate source was fructose instead of glucose or starch. Intestinal and renal Ca2+ transporter activity and expression did not vary with dietary carbohydrate. To determine the time course of fructose effects, a high fructose or glucose diet with normal Ca2+ levels was fed to adult rats for three mo. Serum levels of 1,25(OH)(2)D-3 decreased and of FGF23 increased significantly over time. Renal expression of CYP27B1 and serum levels of 1,25(OH)(2)D-3 still decreased in fructose-compared to those in glucose-fed rats after three mo. Serum parathyroid hormone, Ca2+ and phosphate levels were normal and independent of dietary sugar as well as time of feeding. Thus, chronically high fructose intakes can decrease serum levels of 1,25(OH)(2)D-3 in adult rodents experiencing no Ca2+ stress and fed sufficient levels of dietary Ca2+. This finding is highly significant because fructose constitutes a substantial portion of the average diet of Americans already deficient in vitamin D

Expression of 1,25(OH)₂D₃ metabolizing enzymes and of Ca²⁺transporters in the kidney of mice fed for three mo a high fructose, starch, or glucose diet containing normal Ca²⁺ levels.

<p>(A) Marked effects of excessive fructose intake on mRNA expression levels of renal 1,25(OH)₂D₃ metabolic enzymes, CYP27B1 and CYP24A1. (B) mRNA expression levels of renal TRPV6, CaBP28k, CaBP9k and PMCA1. All expression data were analyzed by real-time PCR using <i>EF1</i>α as a reference and normalized relative to levels seen in mice fed glucose diet. Data are means ± SEM (<i>n</i> = 5 per group). Differences (<i>P</i><0.05) among means are indicated by differences in superscript letters, as analyzed by 1-way ANOVA LSD. Thus, within a gene of interest, bars with superscript “a” are > bars with “b”. Chronic consumption of high fructose levels has dramatic effects on mRNA expression of renal 1,25(OH)₂D₃ metabolizing enzymes but not on Ca²⁺ transporter mRNA expression.</p

Fructose inhibits compensatory increases in renal expression of the 1,25(OH)₂D₃ metabolizing enzyme CYP27B1 induced by dietary Ca²⁺deficiency in mice.

<p>(A) mRNA expression levels of renal CYP27B1 (1α-hydroxylase) and CYP24A1 (24-hydroxylase). (B) The protein abundance of CYP27B1 and CYP24A1, using β-actin as a reference. (C) mRNA expression levels of renal TRPV6, CaBP28k, CaBP9k and PMCA1. Nor  =  normal; G  =  glucose; F  =  fructose. All mRNA expression level data were analyzed by real-time PCR using <i>EF1</i>α as a reference and normalized to levels in mice fed glucose and normal Ca²⁺ diet. Data are means ± SEM (<i>n</i> = 5–6 per group). Differences (<i>P</i><0.05) among means are indicated by differences in superscript letters, as analyzed by 1-way ANOVA LSD. Thus, within a gene of interest, bars with superscript “a” are > bars with “b” which in turn > bars with “c”. Dietary fructose inhibits compensatory increases in renal expression of Ca²⁺ transporters and 1,25(OH)₂D₃ metabolizing enzymes induced by dietary Ca²⁺-deficiency.</p

Chronic consumption of fructose has no significant effect on intestinal Ca²⁺ transport rate and transporter mRNA expression in mice fed for three mo a high fructose, starch, or glucose diet containing normal Ca²⁺ levels.

<p>(A) Active transduodenal Ca²⁺ transport from the luminal to the basolateral compartment was expressed as a ratio of the final quantity of (⁴⁵Ca²⁺ inside/⁴⁵Ca²⁺ outside) of the everted sacs of mice fed diets containing 63% fructose, glucose or starch. (B) mRNA expression levels of intestinal Ca²⁺ (TRPV6, CaBP9k, PMCA1) transporters. All expression data were analyzed by real-time PCR using <i>EF1</i>α as a reference and normalized relative to levels seen in mice fed glucose diet. Data are means ± SEM (<i>n</i> = 5 per group). Chronic consumption of high fructose levels has no significant effect on intestinal Ca²⁺ transport rate and transporter mRNA expression.</p

Blood chemistry of mice after consuming glucose- or fructose-based low and normal Ca^2<b>+</b> diets for five weeks.

<p>Normal Ca²⁺  = 0.5%; Low Ca²⁺  = 0.02%; Glucose or Fructose = 43%; FGF  =  fibroblast growth factor. <i>n</i> = 5–6 per group. Data are means ± SEM. Means with different superscript letters are significantly different from others in the same row (<i>P</i><0.05 by <i>posthoc</i> LSD test).</p