Stimulation Of Calcium Absorption Research Articles

Carrot firmness and yield increased while skin defects reduced by stimulated calcium absorption

Carrot firmness and yield increased while skin defects reduced by stimulated calcium absorption

Enhancement of intestinal calcium transport by short-chain fatty acids: roles of Na+/H+ exchanger 3 and transient receptor potential vanilloid subfamily 6.

Small organic molecules in the intestinal lumen, particularly short-chain fatty acids (SCFAs) and glucose, have long been postulated to enhance calcium absorption. Here, we used 45Ca radioactive tracer to determine calcium fluxes across the rat intestine after exposure to glucose and SCFAs. Confirming previous reports, glucose was found to increase the apical-to-basolateral calcium flux in the cecum. Under apical glucose-free conditions, SCFAs (e.g., butyrate) stimulated the cecal calcium fluxes by approximately twofold, while having no effect on proximal colon. Since SCFAs could be absorbed into the circulation, we further determined whether basolateral SCFA exposure rendered some positive actions. It was found that exposure of duodenum and cecum on the basolateral side to acetate or butyrate increased calcium fluxes. Under butyrate-rich conditions, cecal calcium transport was partially diminished by Na+/H+ exchanger 3 (NHE3) inhibitor (tenapanor) and nonselective transient receptor potential vanilloid subfamily 6 (TRPV6) inhibitor (miconazole). To confirm the contribution of TRPV6 to SCFA-stimulated calcium transport, we synthesized another TRPV6 inhibitor that was demonstrated by in silico molecular docking and molecular dynamics to occlude TRPV6 pore and diminish the glucose- and butyrate-induced calcium fluxes. Therefore, besides corroborating the importance of luminal molecules in calcium absorption, our findings provided foundation for development of more effective calcium-rich nutraceuticals in combination with various absorptive enhancers, e.g., glucose and SCFAs.NEW & NOTEWORTHY Organic molecules in the intestinal lumen, e.g., glucose and short-chain fatty acids (SCFAs), the latter of which are normally produced by microfloral fermentation, can stimulate calcium absorption dependent on transient receptor potential vanilloid subfamily 6 (TRPV6) and Na+/H+ exchanger 3 (NHE3). A selective TRPV6 inhibitor synthesized and demonstrated by in silico docking and molecular dynamics to specifically bind to the pore domain of TRPV6 was used to confirm a significant contribution of this channel. Our findings corroborate physiological significance of nutrients and SCFAs in enhancing calcium absorption.

Menthol stimulates calcium absorption in the rumen but not in the jejunum of sheep

Stimulation of Ca2+ absorption can counteract hypocalcemia at the onset of lactation. The plant bioactive lipid compound (PBLC) menthol is an agonist for nonselective cation channels of the transient receptor potential (TRP) family. It acutely stimulated Ca2+ absorption in ruminal epithelia of nonadapted animals ex vivo and caused higher plasma Ca2+ concentrations in cows and sheep in vivo. To elucidate the pathway by which menthol feeding increases plasma Ca2+ level, the present study aimed to investigate the long-term dose-dependent effects of dietary menthol-rich PBLC on Ca2+ absorption and mRNA abundances of TRP channels in both rumen and jejunum. Twenty-four growing Suffolk sheep were equally distributed to a Con, PBLC-L, and PBLC-H group, which received 0, 80, and 160 mg/d of a menthol-rich PBLC. After 4 wk, ruminal and jejunal epithelia were analyzed for mRNA abundances of TRPA1, TRPV3, TRPV5-6, and TRPM6-8 genes. The Ca2+ flux rates and electrophysiological properties of epithelia from rumen and mid-jejunum were measured in Ussing chambers in the presence and absence of mucosal Na+. Acute changes in Ca2+ flux rates were measured after mucosal application of 50 µM menthol. Ruminal epithelia had quantifiable transcripts of TRPV3 = TRPM6 >TRPM7 >TRPA1 with no difference among feeding groups. Jejunum had quantifiable transcripts of TRPM7 >TRPA1 ≥ TRPM6 ≥ TRPV6 >TRPV5, where TRPA1, TRPV5, and TRPV6 tended to decrease linearly with increasing PBLC dose. Absorptive net flux of Ca2+ was detected only in the rumen, whereas jejunum showed a high passive permeability to Ca2+. Net flux rates of Ca2+ in the rumen increased in a quadratic manner (highest in PBLC-L animals) and were systematically decreased with the omission of mucosal Na+. Short-circuit current increased in both PBLC feeding groups compared with Con only in the rumen. Acute application of menthol-stimulated mucosal-to-serosal and net Ca2+ flux rates only in ruminal epithelia with higher stimulation in PBLC-fed animals. We conclude that Ca2+ transport is mainly active and transcellular in the rumen. It most likely involves TRPV3 that can be stimulated by menthol. Pre-feeding of menthol-rich PBLC enhances ruminal Ca2+ absorption and sensitizes it to acute stimulation by menthol. By contrast, intestinal Ca2+ absorption is not sensitive to menthol stimulation. Menthol could be used as a tool to enhance ruminal Ca2+ absorption and to prevent hypocalcemia in dairy cows.

Elaboração de pão de forma adicionado de yacon

Yacon (Smallanthus sonchifolius) é uma raiz tuberosa de origem Andina, considerada um alimento funcional, por conter fruto-oligossacarídeos (FOS) e compostos fenólicos. O consumo de FOS melhora o crescimento de bifidobactérias no intestino, o metabolismo gastrointestinal e estimula a absorção do cálcio, tem efeito antioxidante, reduz os níveis de colesterol e de glicose sérico. Através desse trabalho, objetivou-se avaliar o aproveitamento integral da batata yacon na elaboração de pães de forma. Foram elaborados 3 pães com concentrações de 5%, onde a primeira formulação foi composta pela farinha da polpa, a segunda contendo a farinha da casca e a terceira utilizando as farinhas da casca e da polpa da batata. Após o processamento, as formulações foram submetidas às análises microbiológicas onde apresentaram resultados negativos para coliformes totais e fecais e Salmonella sp. Os resultados do teste de ordenação por preferência e da análise sensorial para os atributos textura e sabor demonstraram que não houve diferença significativa entre nenhuma das formulações. A formulação 2 com a farinha da casca e a formulação 1 com a farinha da polpa, apresentaram uma boa aceitação, com relação a intenção de compra, indicando possibilidade de comercialização destes produtos. Os resultados obtidos neste estudo contribuíram de forma significativa para estimular o aproveitamento integral da batata yacon na elaboração de um pão diferenciado, com potencial para a comercialização e podendo apresentar um alto valor nutricional.

New aspects of vitamin D metabolism and action - addressing the skin as source and target.

Vitamin D has a key role in stimulating calcium absorption from the gut and promoting skeletal health, as well as many other important physiological functions. Vitamin D is produced in the skin. It is subsequently metabolized to its hormonally active form, 1,25-dihydroxyvitamin D (1,25(OH)2D), by the 1-hydroxylase and catabolized by the 24-hydroxylase. In this Review, we pay special attention to the effect of mutations in these enzymes and their clinical manifestations. We then discuss the role of vitamin D binding protein in transporting vitamin D and its metabolites from their source to their targets, the free hormone hypothesis for cell entry and HSP70 for intracellular transport. This is followed by discussion of the vitamin D receptor (VDR) that mediates the cellular actions of 1,25(OH)2D. Cell-specific recruitment of co-regulatory complexes by liganded VDR leads to changes in gene expression that result in distinct physiological actions by 1,25(OH)2D, which are disrupted by mutations in the VDR. We then discuss the epidermis and hair follicle, to provide a non-skeletal example of a tissue that expresses VDR that not only makes vitamin D but also can metabolize it to its hormonally active form. This enables vitamin D to regulate epidermal differentiation and hair follicle cycling and, in so doing, to promote barrier function, wound healing and hair growth, while limiting cancer development.

Potential non-dairy probiotic products – A healthy approach

Abstract The consumer demand has changed from energy providing diet to the diet with balanced nutrient profile along with metabolic, physiological, health and functional benefits. Probiotics, neutraceutical and functional foods belong to such diet category. Probiotics are selective viable micro-organisms administered in adequate amount to confer health benefits beyond inherent general nutrition. These microorganisms have various health promoting functions like prevents intestinal tract infections, improves lactose metabolism, reduces serum cholesterol level, enhance immunity, stimulates calcium absorption, improves protein digestibility, synthesis of vitamins (vitamin B, nicotinic acid and folic acid), and counteracts the effects of food-borne pathogens. For wider distribution and acceptability, probiotic must be low cost, convenient and viable during the processing, storage and consumption. Consumer health consideration from the perspective of cholesterol in probiotic dairy products for the developed countries and economic reasons for the developing countries has diverted research towards non-dairy based probiotics. This has led to development of rapidly emerging cereals, legumes, fruits and vegetables based non-dairy probiotics. These alternative sources are cheaper in cost, possess more phytochemicals and can reduce the risk of cholesterol problems in lactose intolerance people.

The study for effect of running on bone.

Running-exercise is a weight-bearing-exercise. Power of an effect for running-exercise might be different by exercise intensity, running speed, and duration time. In general, running-exercise could be effective on bone. However, in case of Female Athlete Triad, under the condition of low energy availability running-exercise should not be effective positively for bone. Influence of appropriate mechanical stress, stimulate calcium absorption, and so on through running-exercise could be effective positively for bone.

Pre-suckling calcium supplementation effectively prevents lactation-induced osteopenia in rats

During lactation, osteoclast-mediated bone resorption and intestinal calcium hyperabsorption help provide extra calcium for lactogenesis. Since the suckling-induced surge of pituitary prolactin (PRL) rapidly stimulates calcium absorption in lactating rats, it is hypothesized that pre-suckling oral calcium supplementation should be an efficient regimen to shift the calcium source from bone to diet, thereby slowing lactation-induced osteopenia. Our results showed that 30-min suckling markedly stimulated maternal duodenal calcium transport, which returned to the baseline at 45 min. Lactating rats given 4 mg/kg per dose calcium via a gavage tube at 90 min pre-suckling 4 doses a day for 14 days prevented a decrease in bone mineral density (BMD) of long bones and vertebrae. On the other hand, a single-dose supplementation, despite the same amount of calcium per day, appeared less effective. Because glucose and galactose further stimulated duodenal calcium transport in lactating rats, pre-suckling calcium supplement containing both sugars successfully normalized plasma ionized calcium and led to better bone gain than that with calcium alone. A histomorphometric study revealed that lactating rats given pre-suckling calcium plus monosaccharide supplement manifested greater trabecular bone volume and thickness and exhibited less eroded surface than in vehicle-treated lactating rats. Beneficial effects of the 14-day calcium supplementation persisted until 6 mo postweaning in dams and also elevated the baseline BMD of the offspring. In conclusion, our proof-of-concept study has corroborated that pre-suckling calcium supplements, especially regimens containing monosaccharides, are efficient in preventing osteopenia in lactating rats and could increase bone density in both breastfeeding mothers and neonates.

Benefits of vitamin D for allergic airways

Benefits of vitamin D for allergic airways

Prolactin stimulates the L-type calcium channel-mediated transepithelial calcium transport in the duodenum of male rats

Elevated plasma levels of prolactin (PRL) have been reported in several physiological and pathological conditions, such as lactation, prolactinoma, and dopaminergic antipsychotic drug uses. Although PRL is a calcium-regulating hormone that stimulates intestinal calcium absorption in lactating rats, whether PRL is capable of stimulating calcium absorption in male rats has been elusive. Herein, the transepithelial calcium transport and electrical characteristics were determined in ex vivo duodenal tissues of male rats by Ussing chamber technique. We found that PRL receptors were abundantly present in the basolateral membrane of the duodenal epithelial cells. PRL (200–800ng/mL) markedly increased the active duodenal calcium transport in a dose-dependent fashion without effect on the transepithelial resistance. The PRL-enhanced active duodenal calcium transport was completely abolished by L-type calcium channel blocker (nifedipine) as well as inhibitors of the major basolateral calcium transporters, namely plasma membrane Ca2+-ATPase and Na+/Ca2+ exchanger. Several intracellular mediators, such as JAK2, MEK, PI3K and Src kinase, were involved in the PRL-enhanced transcellular calcium transport. Moreover, PRL also stimulated the paracellular calcium transport in the duodenum of male rats in a PI3K-dependent manner. In conclusion, PRL appeared to be a calcium-regulating hormone in male rats by enhancing the L-type calcium channel-mediated transcellular and the paracellular passive duodenal calcium transport. This phenomenon could help restrict or alleviate negative calcium balance and osteoporosis that often accompany hyperprolactinemia in male patients.

Inulin: A Review of its Functional Properties in Relation to Calcium Absorption in Humans

Inulin is a term applied to a heterogeneous blend of fructose polymers found widely distributed in nature as plant storage carbohydrates. Recent evidence suggests a role for inulin in enhancing Ca absorption and thereby promoting bone health. Numerous investigations performed using animal models during the past 10 years have consistently shown that inulin stimulates calcium absorption and increases bone mineral content. Short and long term human studies have indicated that inulin increases Ca absorption in adolescents. This article reviews current research studies (both animal and human) that have been conducted to determine inulin's role in enhancing Ca metabolism. Animal studies appear to confirm inulin-type fructans' positive role in enhancing Calcium absorption from the gut while several short-term human studies indicate a similar trend. However, the evidence for the positive effects of inulin on Ca metabolism in man, in particular adults and post-menopausal women, is currently inadequate and awaits well planned long-term human trials before any firm conclusions can be reached. Keywords: : Inulin; Inulin-type fructans; Calcium Absorption; Bone Health DOI: 10.4038/jfa.v1i1.1837 Journal of Food and Agriculture Vol.1(1) 2008 pp.26-35

Dietary polydextrose increases calcium absorption in normal rats

BACKGROUND: Gastric surgery is known to cause bone disorders, possibly related to an impaired capacity for the absorption of dietary calcium. AIM: To verify if polydextrose (PDX) could stimulate calcium absorption in partially gastrectomized and sham operated rats. METHODS: The rats were laparotomized (sham-operated control) or partially gastrectomized (Billroth II), in groups of 20 each. Half in each operated group were fed a control diet (AIN-93M) without PDX or the same diet containing (PDX 50g/Kg of diet) for eight weeks. The rats were divided into four subgroups: sham-operated and gastrectomized without PDX; sham-operated and gastrectomized with PDX. On the final day of the study, total blood was collected for determination of serum calcium concentration. RESULTS: In the diet with PDX, excretion of calcium in the feces was significantly lower than in the groups not receiving PDX, irrespective of the operation. Apparent calcium absorption and serum calcium was higher in the sham operated PDX fed group than in the control group. In sham operated rats, the calcium concentration in bone was higher in the PDX fed group. CONCLUSION: The polydextrose feeding increased calcium absorption and bone calcium concentration in normal rats, which may be relevant for decreasing the risk of osteoporosis. Partially gastrectomy did not affect the bone calcium concentration in 56 days of experimental period.

Direct stimulation of the transcellular and paracellular calcium transport in the rat cecum by prolactin

Prolactin (PRL) is reported to stimulate calcium absorption in the rat's small intestine. However, little is known regarding its effects on the cecum, a part of the large intestine with the highest rate of intestinal calcium transport. We demonstrated herein by quantitative real-time polymerase chain reaction and Western blot analysis that the cecum could be a target organ of PRL since cecal epithelial cells strongly expressed PRL receptors. In Ussing chamber experiments, PRL enhanced the transcellular cecal calcium absorption in a biphasic dose-response manner. PRL also increased the paracellular calcium permeability and passive calcium transport in the cecum, which could be explained by the PRL-induced decrease in transepithelial resistance and increase in cation selectivity of the cecal epithelium. PRL actions in the cecum were abolished by inhibitors of phosphoinositide 3-kinase (PI3K), protein kinase C (PKC), and RhoA-associated coiled-coil forming kinase (ROCK), but not inhibitors of gene transcription and protein biosynthesis. In conclusion, PRL directly enhanced the transcellular and paracellular calcium transport in the rat cecum through the nongenomic signaling pathways involving PI3K, PKC, and ROCK.

Vitamin D

The primary source of vitamin D is the skin, following exposure to ultraviolet radiation. Vitamin D is well known for its effects on stimulating calcium absorption and is thus essential for maintenance of normal bone. It is also important for muscle function and has more recently been implicated in protection against several diseases including diabetes. Different pathways of action have been described for vitamin D compounds and various analogs specific to these pathways have demonstrated potential for therapeutic use. Recent studies suggest a novel role for vitamin D compounds in protection against cancer, a proposal supported by substantial epidemiological evidence.

A Prebiotic Substance Persistently Enhances Intestinal Calcium Absorption and Increases Bone Mineralization in Young Adolescents

A number of short-term (9 days to 5 weeks) studies have reported that non-digestible. oligosaccharides enhance intestinal calcium absorption. Recent interesting data from an intervention trial in adolescents (9-13 years of age) suggest that a non-digestible oligosaccharide can persistently stimulate calcium absorption over 12 months and can also enhance bone mineralization during pubertal growth.

Gene expression profiles in rat intestine identify pathways for 1,25-dihydroxyvitamin D 3 stimulated calcium absorption and clarify its immunomodulatory properties

Microarray technology has been used to discover 1,25-dihydroxyvitamin D 3 (1,25-(OH) 2D 3) induced gene expression changes in rat small intestine in vivo. Here, we report gene expression changes related to intestinal absorption or transport, the immune system and angiogenesis in response to 1,25-(OH) 2D 3. Vitamin D deficient rats were intrajugularly given vehicle or vehicle containing 730 ng of 1,25-(OH) 2D 3/kg of body weight. Intestinal mRNA was harvested from duodenal mucosa at 15 min, 1, 3, and 6 h post-injection and studied by Affymetrix microarrays. Genes significantly affected by 1,25-(OH) 2D 3 were confirmed by quantitative RT-PCR with remarkable agreement. The most strongly affected gene in intestine was CYP24 with 97-fold increase at 6 h post-1,25-(OH) 2D 3 treatment. Intestinal calcium absorption genes: TRPV5, TRPV6, calbindin D 9k, and Ca 2+ dependent ATPase all were up-regulated in response to 1,25-(OH) 2D 3, supporting the currently accepted mechanism of 1,25-(OH) 2D 3 induced transcellular calcium transport. However, a 1,25-(OH) 2D 3 suppression of several intra-/intercellular matrix modeling proteins such as sodium/potassium ATPase, claudin 3, aquaporin 8, cadherin 17, and RhoA suggests a vitamin D regulation of tight junction permeability and paracellular calcium transport. Several other genes related to the immune system and angiogenesis whose expression was changed in response to 1,25-(OH) 2D 3 provided evidence for an immunomodulatory and anti-angiogenic role of 1,25-(OH) 2D 3.

Nondigestible Oligosaccharides Increase Calcium Absorption and Suppress Bone Resorption in Ovariectomized Rats

Nondigestible oligosaccharides (NDO) including inulin and fructooligosaccharides (FOS) have been reported to stimulate calcium absorption. Here we report the effect of a mixture of inulin and FOS (Raftilose Synergy 1, Orafti) on calcium and bone metabolism in ovariectomized (OVX) rats. OVX rats (6 mo old) were fed a semipurified diet for 3 mo in our animal care laboratory for stabilization after ovariectomy. They were then divided into two groups (n = 13/group) and fed either a control or a NDO-supplemented diet (55 g/kg) for 21 d. Catheters were placed in their jugular veins. After 2 d, a tracer ((45)Ca) was administered by gavage or i.v. and blood was sampled for up to 300 min. Urine and fecal samples were collected for 4 d after (45)Ca administration. Femurs were measured for bone mineral density (BMD), breaking strength, and total calcium. Calcium absorption, femoral calcium content, BMD, and bone balance (V(bal)) were significantly increased (P < 0.05) by NDO, whereas the bone resorption rate relative to the bone formation rate was significantly depressed by NDO. We conclude that feeding NDO at 5.5 g/100 g for 21 d has a positive effect on calcium absorption and retention in ovariectomized rats.

Effect of Difructose Anhydride III on Calcium Absorption in Humans

The effects of difructose anhydride III (DFAIII) on stimulating calcium absorption was investigated in humans. We studied changes in the time-course of characteristics urinary calcium excretion in 12 healthy men given 0.3, 1.0 or 3.0 g of DFAIII and 300 mg of calcium as calcium carbonate. In addition, urinary excretion and urine concentrations of creatinine and deoxypyridinoline were determined. Urine calcium excretion every 2 hours after the intake were higher over than that of the control subjects. The total amount of urinary calcium excretion for 10 hours was significantly greates in the subjects given 1.0 g or 3.0 g of DFAIII than that of the control subjects. However, there were no differences in the urine concentrations of creatinine and deoxypyridinoline between the subjects given DFAIII and the control subjects. These findings suggests that low dose of DFAIII had a stimulating effect on calcium absorption in humans.

The optimum amount of vitamin D for osteoporosis: in case of activated vitamin D treatment

Since the resistance factors for the effect of vitamin D increases by aging, ingestion of various nutrition factors, such as calcium, and vitamin D is important for prevention and medical treatment of osteoporosis. 1 alpha 25-dihydroxyvitamin D(3) known as active form of vitamin D can stimulate calcium absorption from intestine and also it is used for the medical treatment of osteoporosis. The vitamin D action for the regulation of bone and mineral metabolism changes with the sufficiency states or the amounts of ingestion of vitamin D. Therefore, the action as a medicine is not simple. This article reviews the effect and its optimum ingestion amount of activated vitamin D in osteoporosis medical treatment.

A calcium homeostasis model: orchestration of fast acting PTH and calcitonin with slow calcitriol

Calcitriol is in plasma bound to transcalciferin and this results in a long calcitriol half-life in plasma (5–12 h). Abundance of bound calcitriol molecules prevents the exact and quick control of its effects and makes it an inert regulator with a time lag between the changes of calcitriol synthesis and its effect on peripheral tissues. The added regulatory inertia is here defined as: calcitriol bound/calcitriol free and it approaches value of 99. Estrogens increase transcalciferin levels. It is possible that the estrogen-induced increase in the total calcitriol plasma pool makes calcitriol effects even more inert, augmenting and prolonging the calcitriol effects and thus improving calcium balance in women. Since calcitriol synthesis in kidneys depends on the PTH level, it can be assumed that the size of the total calcitriol pool in plasma reflects more the average PTH secretion during previous hours, than the high or low peaks of PTH secretion in the same period. In other words, one or more PTH tides of short duration are followed with a late calcitriol tide that lasts for hours, and even longer lasting rise in calcitriol effects. Bone integrity depends also on the cortisol level. A possible speculation is that the main result of all profound bone effect of hypecortisolemia, might be reduction of the bone amino acids uptake, thus allowing redistribution of available proteins. Both PTH and calcitriol prevent dangerous hypocalcemia. PTH is quick in mobilizing bone calcium, while calcitriol tends to increase absorption of dietary calcium. In case of low or no dietary calcium, calcitriol mobilizes bone calcium and thus increase PTH initiated demineralization. In the case of calcium abundance, increased plasma calcium reduces PTH levels. Calcitriol plasma level (reflecting previous PTH surges) can induce both calcium absorption and bone demineralization. This two-blade action is tuned by calcitonin that reduces osteoclastic bone resorption, allowing bone deposition of abundant calcium. An overnight fast with a reduced absorption of dietary calcium, might decrease plasma calcium below the regulatory set point, inducing an increase in PTH secretion. Increased average nighttime PTH secretion induces more calcitriol to be synthesized in kidneys. The resultant late calcitriol morning and daytime tide would stimulate calcium absorption from gut, or from bone, depending on the availability of dietary calcium. Due to the described time lag in calcitriol effects, increased calcium absorption might continue during daytime, regardless of the plasma calcium level. If plasma calcium is above the set point, calcitonin will allow excess calcium to deposit in bones. A speculation based on this model is that it might be more efficient to avoid calcium rich food for dinner or supper, and to administer calcium supplementation in the morning, during the calcitriol tide.