An overview of current information on the mechanisms by which intestinal calcium absorption occurs is described in this article. Both paracellular and transcellular pathways are analyzed. Special emphasis focuses on molecules participating in the latter pathway, such as TRPV5 and TRPV6 channels, located in the apical region of the enterocytes, CB9k and CB28k, presumably involved in the cation movement from the apical to the basolateral pole of the cell, and PMCA1b and Na+/Ca2+ exchanger, proteins that extrude Ca2+ from the cells. Current concepts on the relative importance of paracellular and transcellular calcium transport and the vitamin D dependence of each pathway are referred and analyzed showing the contrasting views on this issue. More detailed information is given regarding the stimulatory effect of vitamin D on intestinal Ca2+ absorption either in animal models or in the human intestine. The possible mechanisms triggered by hormones such as PTH, calcitonin, estrogen, thyroid hormone, glucocorticoids and different nutritional factors on intestinal calcium absorption are also reviewed. Finally, the influence of physiological conditions such as growth, pregnancy, lactation and aging on intestinal calcium absorption are discussed.
Background: Naringin (NAR) is a flavonoid enriched in several medicinal plants and fruits. An increasing interest in this molecule has been emerging because it has the potential to contribute to alleviating many health problems. Objective:: This review briefly describes the NAR pharmacokinetics and it mainly focus on in vitro and in vivo animal studies showing NAR beneficial effects on cardiovascular, metabolic, neurological and pulmonary disorders and cancer. The anabolic effects of NAR on different models of bone and dental diseases are also analyzed. In addition, the evidence of the NAR action on the gastrointestinal tract is reported as well as its influence on the microbiota composition and activity. Finally, current research on NAR formulations and clinical applications are discussed. Methods: The PubMed database was searched until 2019, using the keywords NAR, naringenin, cardiovascular and metabolic disorders, neurological and pulmonary disorders, cancer, bone and dental diseases, gastrointestinal tract, microbiota, NAR formulations, clinical trials. Results: The number of studies related to the bioavailability and pharmacokinetics of NAR is limited. Positive effects of NAR have been reported on cardiovascular diseases, type 2 Diabetes mellitus (T2DM), metabolic syndrome, pulmonary disorders, neurodegenerative diseases, cancer and gastrointestinal pathologies. Current NAR formulations seem to improve its bioavailability, which would allow its clinical application. Conclusion: NAR is endowed with broad biological effects that could improve human health. Since a scarce number of clinical studies have been performed, the use of them requires more investigation in order to know better their safety, efficacy, delivery and bioavailability in humans.
The aim of this study was to determine genotypes and clinical aspects associated with bone mineral density (BMD) in postmenopausal women from Córdoba, Argentina. Polymorphisms were assessed by RFLP-PCR technique using BsmI and FokI for vitamin D receptor gene (VDR) and XbaI and PvuII for estrogen receptor-alpha gene (ERalpha) as restrictases. Sixty-eight healthy, 54 osteopenic, and 64 osteoporotic postmenopausal women were recruited. Femoral neck and lumbar spine BMD were inversely correlated with age in the entire analyzed population. Height was lower in osteopenic and osteoporotic women as compared to healthy women (P < 0.05). Weight and body mass index (BMI) were the lowest in osteoporotic women (P < 0.01 versus healthy group). Serum procollagen type I Nterminal propeptide (PINP) was higher in osteoporotic women as compared to the other groups. Distribution of VDR and ERalpha genotypes was similar in the three groups. Genotype bb (VDR) was associated with low values of lumbar BMD in the healthy group (P < 0.05 versus genotype Bb), and with low values of femoral BMD (P < 0.05 versus genotype BB) in osteoporotic women. BB*Pp interaction was associated with the highest femoral neck BMD (P < 0.05), whereas the bb*xx interaction was associated with the lowest femoral neck BMD in the total population analyzed (P < 0.05). In conclusion, parameters such as age, height, weight, BMI, serum PINP, VDR genotypes, and interactions between VDR and ERalpha genotypes could be useful to predict a decrease in BMD in Argentine postmenopausal women.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.