Abstract
Ca(2+) is an essential ion in all organisms, where it plays a crucial role in processes ranging from the formation and maintenance of the skeleton to the temporal and spatial regulation of neuronal function.
The Ca(2+) balance is maintained by the concerted action of three organ systems, including the gastrointestinal tract, bone, and kidney.
An adult ingests on average 1 g Ca(2+) daily from which 0.35 g is absorbed in the small intestine by a mechanism that is controlled primarily by the calciotropic hormones. To maintain the Ca(2+) balance, the kidney must excrete the same amount of Ca(2+) that the small intestine absorbs. This is accomplished by a combination of filtration of Ca(2+) across the glomeruli and subsequent reabsorption of the filtered Ca(2+) along the renal tubules.
Bone turnover is a continuous process involving both resorption of existing bone and deposition of new bone.
The above-mentioned Ca(2+) fluxes are stimulated by the synergistic actions of active vitamin D (1,25-dihydroxyvitamin D(3)) and parathyroid hormone.
Until recently, the mechanism by which Ca(2+) enter the absorptive epithelia was unknown. A major breakthrough in completing the molecular details of these pathways was the identification of the epithelial Ca(2+) channel family consisting of two members: TRPV5 and TRPV6. Functional analysis indicated that these Ca(2+) channels constitute the rate-limiting step in Ca(2+)-transporting epithelia.
They form the prime target for hormonal control of the active Ca(2+) flux from the intestinal lumen or urine space to the blood compartment.
This review describes the characteristics of epithelial Ca(2+) transport in general and highlights in particular the distinctive features and the physiological relevance of the new epithelial Ca(2+) channels accumulating in a comprehensive model for epithelial Ca(2+) absorption.
See also:
- Official Web Site: The Di Bella Method;
- The Di Bella Method (A Fixed Part - Calcium, 2 grams per day, orally);
- Vitamin D (analogues and/or derivatives) and cancer - In vitro, review and in vivo publications;
- The Di Bella Method (A Fixed Part - Dihydrotachysterol, Alfacalcidol, synthetic Vitamin D3);
- Solution of retinoids in vitamin E in the Di Bella Method biological multitherapy;
- Complete objective response to biological therapy of plurifocal breast carcinoma;
- Neuroblastoma: Complete objective response to biological treatment;
- Oesophageal squamocellular carcinoma: a complete and objective response;
- Pancreatic Adenocarcinoma: clinical records on 17 patients treated with Di Bella's Method;