The intestinal calcistat: Determinant of clinical vitamin D deficiency

Garg, MK; Kalra, Sanjay; Mahalle, Namita

doi:10.4103/2230-8210.117187

Cited by 6 publications

(5 citation statements)

References 24 publications

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“…[ 4 5 7 ] After excluding the possibility of co-existing non-PTH mediated hypercalcemia, a number of theories have been proposed to explain this functional hypoparathyroidism. They include redefining the upper normal limits of PTH levels in the normal population,[ 8 ] intestinal calcium absorption adaptation theory (intestinal calcistat),[ 9 10 11 ] circadian variations in PTH,[ 12 ] magnesium (Mg) deficiency[ 13 ] and lastly the variations in Vitamin D binding protein among population[ 14 ] and its impact on the free Vitamin D levels.…”

Section: Introductionmentioning

confidence: 99%

Estimation of magnesium in patients with functional hypoparathyroidism

Kannan

Mahadevan

Velayutham

et al. 2014

Indian J Endocr Metab

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Context:It is evident that about 30-50% of patients with Vitamin D deficiency (VDD) do not manifest develop secondary hyperparathyroidism (SHPT). A number of theories have been proposed to explain this lack of SHPT, including hypomagnesemia.Settings and Design:Retrospective review of laboratory database.Materials and Methods:We evaluated the differences in serum magnesium (Mg) levels among those with VDD with or without SHPT. A retrospective review of 6255 laboratory data of bone mineral profiles performed in the period of 2007–2013. After excluding patients with hypercalcemia, renal dysfunction/unknown kidney function and primary hypothyroidism, the remaining 1323 patient data were analyzed. SHPT was defined as serum parathyroid hormone >65 in those with VDD.Statistical Analysis Used:ANOVA and Wilcoxon tests as appropriate to compare means. Multivariate logistic regression to analyze relation between variables and outcome of SHPT.Results:We noted that 55% patients (n = 727) had VDD, and among those who had VDD, 23% (n = 170) were hypocalcemic (corrected serum calcium <8.5). Patients with VDD who did not exhibit SHPT were 56% (n = 407). The mean (±standard deviation) serum Mg levels in the entire cohort (n = 1323) was 1.94 ± 0.26 mg/dl and 1.95 ± 0.26 mg/dl in VDD cohort and 2 ± 0.31 mg/dl in the VDD-hypocalcemic cohort. There was no statistical difference in the Mg levels among those with SHPT compared to those without SHPT (P = 0.14). Serum calcium and phosphorus were lower in those with SHPT (P = 0.06 and P < 0.001, respectively). In multivariate logistic regression, serum calcium (P = 0.043), phosphorus (P < 0.001) and severe VDD (P < 0.001) independently correlated with occurrence of SHPT in VDD.Conclusions:Serum Mg levels did not explain the functional hypoparathyroidism seen in about half of the patients with VDD. A low normal serum calcium and phosphorus levels are more likely to be associated with VDD patients who develop SHPT.

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Section: Introductionmentioning

confidence: 99%

Estimation of magnesium in patients with functional hypoparathyroidism

Kannan

Mahadevan

Velayutham

et al. 2014

Indian J Endocr Metab

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“…According to our immunohistochemistry results, it showed that positive staining in the apical membranes of both small intestine and colon, suggesting pCaSR is mainly expressed in the apical membranes of pig villus cells. An early study mirrored this result given that it claimed that CaSR appeared on the brush border of the intestine (Garg et al, 2013). However, it is difficult to determine which specific cells express pCaSR by using immunohistochemical staining.…”

Section: Discussionmentioning

confidence: 86%

Distribution and localization of porcine calcium sensing receptor in different tissues of weaned piglets1

Zhao

Schindell

et al. 2019

Journal of Animal Science

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Taste receptors including calcium sensing receptor (CaSR) are expressed in various animal tissues, and CaSR plays important roles in nutrient sensing and the physiology, growth and development of animals. However, molecular distribution of porcine CaSR (pCaSR) in different tissues, especially along the longitudinal axis of the digestive tract in weaned piglets are still unknown. In the present study, we investigated the distribution and localization of pCaSR in the different tissues including intestinal segments of weaned piglets. Six male pigs were anesthetized and euthanized. Different tissues including intestinal segments were collected. The pCaSR mRNA abundance, protein abundance and localization were measured by real-time PCR, Western blotting and immunohistochemistry, respectively. The mRNA and protein of pCaSR were detected in the kidney, lung, liver, stomach, duodenum, jejunum, ileum and colon. The pCaSR mRNA was much higher (5 to 180 times) in the kidney when compared with other tissues (P < 0.05). The ileum had higher pCaSR mRNA and protein abundances than the stomach, duodenum, jejunum and colon (P < 0.05). Immunohistochemical staining results indicated that the pCaSR protein was mostly located in the epithelia of the stomach, duodenum, jejunum, ileum and colon. These results demonstrate that pCaSR is widely expressed in different tissues including intestinal segments in weaned piglets and the ileum has a higher expression level of pCaSR. Further research is needed to confirm the expression of CaSR in the different types of epithelial cells isolated from weaned piglets and characterize the functions of pCaSR, its potential ligands and cell signaling pathways related to CaSR activation in enteroendocrine cells and potentially in enterocytes.

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“…[9] This suggests that it is the calcium absorptive mechanism, rather than dietary calcium intake, will decide the adequacy of calcium homeostasis. An alternative hypothesis has been proposed, wherein the adaptation of calcium absorption occurs at the level of intestine called “intestinal calcistat.”[1011] This “calcistat” senses the calcium intake or available calcium in the gastrointestinal (GI) tract and regulates the generation of active Vitamin D in intestinal cells to adjust FCA. With daily calcium intake of <500 mg, the FCA is about 60%–80%, which can easily supply the daily needs of calcium, i.e., 200 mg.…”

Section: Why – Calcium Supplementation?mentioning

confidence: 99%