Effects of calcium supplementation on biomarkers of inflammation and oxidative stress in colorectal adenoma patients: a randomized controlled trial

A scalable approach to characterize pleiotropy across thousands of human diseases and complex traits using GWAS summary statistics

Genome-wide association studies (GWASs) across thousands of traits have revealed the pervasive pleiotropy of trait-associated genetic variants. While methods have been proposed to characterize pleiotropic components across groups of phenotypes, scaling these approaches to ultra-large-scale biobanks has been challenging. Here, we propose FactorGo, a scalable variational factor analysis model to identify and characterize pleiotropic components using biobank GWAS summary data. In extensive simulations, we observe that FactorGo outperforms the state-of-the-art (model-free) approach tSVD in capturing latent pleiotropic factors across phenotypes while maintaining a similar computational cost. We apply FactorGo to estimate 100 latent pleiotropic factors from GWAS summary data of 2,483 phenotypes measured in European-ancestry Pan-UK BioBank individuals (N = 420,531). Next, we find that factors from FactorGo are more enriched with relevant tissue-specific annotations than those identified by tSVD (p = 2.58E-10) and validate our approach by recapitulating brain-specific enrichment for BMI and the height-related connection between reproductive system and muscular-skeletal growth. Finally, our analyses suggest shared etiologies between rheumatoid arthritis and periodontal condition in addition to alkaline phosphatase as a candidate prognostic biomarker for prostate cancer. Overall, FactorGo improves our biological understanding of shared etiologies across thousands of GWASs.

A scalable variational approach to characterize pleiotropic components across thousands of human diseases and complex traits using GWAS summary statistics

Genome-wide association studies (GWAS) across thousands of traits have revealed the pervasive pleiotropy of trait-associated genetic variants. While methods have been proposed to characterize pleiotropic components across groups of phenotypes, scaling these approaches to ultra large-scale biobanks has been challenging. Here, we propose FactorGo, a scalable variational factor analysis model to identify and characterize pleiotropic components using biobank GWAS summary data. In extensive simulations, we observe that FactorGo outperforms the state-of-the-art (model-free) approach tSVD in capturing latent pleiotropic factors across phenotypes, while maintaining a similar computational cost. We apply FactorGo to estimate 100 latent pleiotropic factors from GWAS summary data of 2,483 phenotypes measured in European-ancestry Pan-UK BioBank individuals (N=420,531). Next, we find that factors from FactorGo are more enriched with relevant tissue-specific annotations than those identified by tSVD (P=2.58E-10), and validate our approach by recapitulating brain-specific enrichment for BMI and the height-related connection between reproductive system and muscular-skeletal growth. Finally, our analyses suggest novel shared etiologies between rheumatoid arthritis and periodontal condition, in addition to alkaline phosphatase as a candidate prognostic biomarker for prostate cancer. Overall, FactorGo improves our biological understanding of shared etiologies across thousands of GWAS.

Effect of calcium lactate in standard diet on selected markers of oxidative stress and inflammation in ovariectomized rats

The effectiveness of calcium depends on its source, i.e., salt it is supplied with. This study aimed to determine the effects of calcium lactate in diet on inflammation and oxidative stress markers in ovariectomized rats. A total of 40 female Wistar rats were included in this study, which were divided into four groups. The control group was fed a standard diet, whereas the remaining three groups were ovariectomized and provided a standard diet containing calcium carbonate (OVX), a calcium-deficient diet (OVX_DEF), or a diet containing calcium lactate (OVX_CaL). The nutritional intervention lasted for 12 weeks, and then, the rats were sacrificed. Tissue and blood samples were taken and evaluated for cyclooxygenase 1 (COX-1), cyclooxygenase 2, and thiobarbituric acid reactive substance contents in the liver and serum, and total antioxidant status and lipoxygenase 1 contents only in the serum using enzyme-linked immunosorbent assay. Differences were observed in the effects of calcium carbonate and calcium lactate on the COX-1 content in the serum of ovariectomized rats: a lower COX-1 concentration was observed in the case of the calcium lactate diet. No significant differences were observed for the other parameters.

The effect of magnesium alone or its combination with other supplements on the markers of inflammation, OS and metabolism in women with polycystic ovarian syndrome (PCOS): A systematic review

The objective of this systematic review is to synthesize the available evidence on the effectiveness of magnesium supplements on the markers of inflammation, oxidative stress (OS), and metabolism in PCOS patients and to provide a basis for its clinical treatment. Electronic databases (PubMed, Cochrane Library databases, Embase, Web of science, CMB, CNKI, VIP, Wan Fang and ClinicalTrials.gov) were searched from their inception until January 2022. Randomized controlled trials (RCTs) for PCOS undergoing therapy with magnesium supplementation alone or in combination with other agents. The primary outcomes were the markers of blood glucose and OS.363 patients from nine RCTs were included in the current systematic review. Four of the nine studies reported the effects of magnesium supplementation alone on OS or metabolic markers in women with PCOS. Whilemagnesium supplementation alone did not show any significant improvement in the markers of inflammation, OS or metabolism in PCOS, seven of the nine articles reported the effect of magnesium co-supplementation on OS or metabolic markers in PCOS patients. Magnesium combined with vitamin E or zinc-calcium-vitamin D significantly improved glucose and lipid metabolism in PCOS patients. Magnesium intake alone did not lead to a significant improvement in the markers of OS, blood glucose, or serum lipids in PCOS. However, magnesium combined with other supplements (vitamin E, zinc, zinc-calcium-vitamin D) significantly improved serum hs-CRP, insulin, HOMA-IR, TG, TC levels, and the improvement in OS markers was inconclusive. The effect of magnesium and melatonin supplementation on the markers of metabolism needs to be further verified.

SYSTEM REVIEW REGISTRATION

PROSPERO https://www.crd.york.ac.uk/PROSPERO/#myprospero, CRD42022303410.

Development and Validation of Novel Dietary and Lifestyle Inflammation Scores

BACKGROUND

Chronically higher inflammation, which may partly result from diet and lifestyle, is implicated in risk for multiple chronic diseases. The dietary inflammatory index (DII) and empirical dietary inflammatory pattern (EDIP), developed to characterize dietary contributions to systemic inflammation, have several limitations. There are no scores to characterize contributions of lifestyle to inflammation.

OBJECTIVES

To reflect dietary/lifestyle contributions to inflammation, we developed novel, inflammation biomarker panel-weighted, dietary (DIS) and lifestyle (LIS) inflammation scores in a subset (n = 639) of the Reasons for Geographic and Racial Differences in Stroke Study (REGARDS) cohort.

METHODS

We selected a priori 19 food groups and 4 lifestyle characteristics to comprise the DIS and LIS, respectively. We calculated the components' weights based on their strengths of association with an inflammation biomarker score [comprising high-sensitivity C-reactive protein (hsCRP), IL-6, IL-8, and IL-10] using multivariable linear regression. The sums of the weighted components constitute the scores, such that higher scores reflect, on balance, more proinflammatory exposures. We calculated the DIS, LIS, DII, and EDIP with cross-sectional data from the remaining REGARDS cohort (  n = 14,210 with hsCRP measurements) and 2 other study populations with hsCRP and/or an 8-component inflammation biomarker panel, and investigated their associations with circulating inflammation biomarker concentrations using multivariable logistic regression.

RESULTS

In REGARDS, those in the highest relative to the lowest DIS, LIS, DII, and EDIP quintiles had statistically significant 1.66-, 4.29-, 1.56-, and 1.32-fold higher odds of a high hsCRP concentration (>3 mg/dL), respectively (all P-trend < 0.001). Those in the highest relative to the lowest joint DIS/LIS quintile had a statistically significant 7.26-fold higher odds of a high hsCRP concentration. Similar findings were noted in the other 2 validation populations.

CONCLUSION

Our results support that dietary and lifestyle exposures collectively contribute substantially to systemic inflammation, and support the use of our novel DIS and LIS.

Vitamin D deficiency in the ApcPirc/+ rat does not exacerbate colonic tumorigenesis, while low dietary calcium might be protective

Human studies have shown that individuals with colon cancer tend to have lower serum 25-hydroxy-vitamin D₃ [25(OH)D₃] levels compared with healthy controls, but whether this link is causative, a result of the disease or an indicator of another factor altogether has yet to be demonstrated. In humans, vitamin D, calcium and UV exposure are inextricably linked; therefore, understanding the individual and combined roles of each of these will require animal models specifically designed to address these questions. To begin to untangle this network, our group has employed the Apc^Pirc/+ rat, which contains a truncating mutation in the Apc gene, leading to the development of colonic tumors. Our group previously utilized this model to demonstrate that vitamin D supplementation above normal does not reduce colonic tumor burden and, in fact, increased tumor multiplicity in a dose-dependent manner. In the current study, we tested whether vitamin D deficiency plays a causative role in tumor development using two strains which differ in their susceptibility to intestinal tumorigenesis. In the colon, vitamin D deficiency did not increase the development of tumors in either strain, and was actually protective in one strain. Unexpectedly, low dietary calcium combined with vitamin D deficiency significantly suppressed tumor development in the small intestine and colon of both strains. The vast majority of tumors in the human intestine occur in the colon, and we find no evidence to support a direct role of vitamin D deficiency in increasing colonic tumorigenesis, and low calcium might protect against tumor development.This article has an associated First Person interview with the first author of the paper.