Calcium Absorption after Intestinal Resection: The Importance of a Preserved Colon

Hylander, E.; Ladefoged, Karin; Jarnum, S.

doi:10.3109/00365529008997596

Cited by 55 publications

(19 citation statements)

References 17 publications

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“…Different from the mouse study, 30 these children are slightly hypocalcemic and the low serum calcium levels may also hinder bone mineralization. Other conditions considered to diminish intestinal calcium absorption are reduced gastric acidification 78 and gastrectomy 79 and they may lead to a negative calcium balance.…”

Section: Human Studiesmentioning

confidence: 99%

Vitamin D endocrine system and the intestine

Christakos¹,

Lieben²,

Masuyama³

et al. 2014

BoneKEy Reports

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Calcium and phosphate regulate numerous biological processes and they are essential for bone mass and bone quality. The calcium and phosphate balance largely depends on intestinal absorption, and the dietary content of these ions determines the type of transport. High dietary intake of calcium and phosphate enables absorption by passive transport, but often the dietary content of these ions is in the low-normal range, especially for calcium. In this condition, the contribution of active intestinal calcium transport will increase to maintain normal serum levels. This adaptation is mainly regulated by the active form of vitamin D, 1,25 dihydroxyvitamin D, and requires normal concentrations of the precursor 25-hydroxyvitamin D. When intestinal calcium absorption is insufficient, hormonal adaptations will release calcium from bones to secure normocalcemia, not only by increasing bone loss but also by decreasing bone mineralization. These data underline the fact that adequate calcium intake is critical to secure skeletal integrity. Despite the insights that sufficient dietary calcium intake and normal 25-hydroxyvitamin D levels are critical for calcium and bone homeostasis, surprisingly little is known on the proteins that mediate intestinal calcium transport. Also, the interaction between the intestine and the kidney to control serum phosphate levels is still incompletely understood.

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Section: Human Studiesmentioning

confidence: 99%

Vitamin D endocrine system and the intestine

Christakos¹,

Lieben²,

Masuyama³

et al. 2014

BoneKEy Reports

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“…The highest expression levels of TRPV6 are in the distal intestine (517). Studies from rats and humans show that total calcium absorption is significantly higher when the colon is preserved after extensive small bowel resection (203,491). In addition, we recently showed that transgenic expression of VDR specifically in ileum, cecum, and colon of Vdr null mice is sufficient to prevent the abnormal calcium homeostasis phenotype of Vdr KO mice (86) (FIGURE 4).…”

Section: Vitamin D and The Distal Intestinementioning

confidence: 99%

Vitamin D: Metabolism, Molecular Mechanism of Action, and Pleiotropic Effects

Christakos

Dhawan

Verstuyf

et al. 2016

Physiological Reviews

1,435

1,234

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, [1,25(OH) 2 D 3 ] is the hormonally active form of vitamin D. The genomic mechanism of 1,25(OH) 2 D 3 action involves the direct binding of the 1,25(OH) 2 D 3 activated vitamin D receptor/retinoic X receptor (VDR/RXR) heterodimeric complex to specific DNA sequences. Numerous VDR co-regulatory proteins have been identified, and genome-wide studies have shown that the actions of 1,25(OH) 2 D 3 involve regulation of gene activity at a range of locations many kilobases from the transcription start site. The structure of the liganded VDR/RXR complex was recently characterized using cryoelectron microscopy, X-ray scattering, and hydrogen deuterium exchange. These recent technological advances will result in a more complete understanding of VDR coactivator interactions, thus facilitating cell and gene specific clinical applications. Although the identification of mechanisms mediating VDR-regulated transcription has been one focus of recent research in the field, other topics of fundamental importance include the identification and functional significance of proteins involved in the metabolism of vitamin D. CYP2R1 has been identified as the most important 25-hydroxylase, and a critical role for CYP24A1 in humans was noted in studies showing that inactivating mutations in CYP24A1 are a probable cause of idiopathic infantile hypercalcemia. In addition, studies using knockout and transgenic mice have provided new insight on the physiological role of vitamin D in classical target tissues as well as evidence of extraskeletal effects of 1,25(OH) 2 D 3 including inhibition of cancer progression, effects on the cardiovascular system, and immunomodulatory effects in certain autoimmune diseases. Some of the mechanistic findings in mouse models have also been observed in humans. The identification of similar pathways in humans could lead to the development of new therapies to prevent and treat disease.

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“…Conservation of the colon is advantageous as it absorbs water, sodium [21][22][23][24][25] , magnesium [25,26] , calcium [27] , short and medium chain fatty acids [28][29][30] , slows gastro-intestinal transit [31] and stimulates small intestinal hyperplasia [32] . Patients with a preserved colon after a small bowel resection may survive without parenteral support with a very short [33,34] or even no remaining jejunum [35] .…”

Section: Colonmentioning

confidence: 99%

Management of patients with a short bowel

Nightingale

1999

Nutrition

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Calcium Absorption after Intestinal Resection: The Importance of a Preserved Colon

Cited by 55 publications

References 17 publications

Vitamin D endocrine system and the intestine

Vitamin D endocrine system and the intestine

Vitamin D: Metabolism, Molecular Mechanism of Action, and Pleiotropic Effects

Management of patients with a short bowel

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