Calcium and Vitamin D Supplementation and Their Association with Kidney Stone Disease: A Narrative Review

Kidney stone disease is a multifactorial condition influenced by both genetic predisposition and environmental factors such as lifestyle and dietary habits. Although different monogenic polymorphisms have been proposed as playing a causal role for calcium nephrolithiasis, the prevalence of these mutations in the general population and their complete pathogenetic pathway is yet to be determined. General dietary advice for kidney stone formers includes elevated fluid intake, dietary restriction of sodium and animal proteins, avoidance of a low calcium diet, maintenance of a normal body mass index, and elevated intake of vegetables and fibers. Thus, balanced calcium consumption protects against the risk for kidney stones by reducing intestinal oxalate availability and its urinary excretion. However, calcium supplementation given between meals might increase urinary calcium excretion without the beneficial effect on oxalate. In kidney stone formers, circulating active vitamin D has been found to be increased, whereas higher plasma 25-hydroxycholecalciferol seems to be present only in hypercalciuric patients. The association between nutritional vitamin D supplements and the risk for stone formation is currently not completely understood. However, taken together, available evidence might suggest that vitamin D administration worsens the risk for stone formation in patients predisposed to hypercalciuria. In this review, we analyzed and discussed available literature on the effect of calcium and vitamin D supplementation on the risk for kidney stone formation.

Protective Effects of Water Extract of Fructus Ligustri Lucidi against Oxidative Stress-Related Osteoporosis In Vivo and In Vitro

Fructus Ligustri Lucidi (FLL) is the fruit of Ligustrum lucidum Ait and is a component of many kidney-tonifying traditional Chinese medicine formulae for treating osteoporosis. Accumulating evidence has linked oxidative stress with the progression of bone diseases. The present study aimed to identify the effects of FLL on oxidative stress-related osteoporosis in vivo and in vitro. To construct animal models, we utilized d-galactose (D-gal) injection to induce oxidative stress combined with a low calcium (the exact percentage in the diet was 0.1%) diet. Thirteen-week-old Kunming female mice were gavaged with water extract of FLL for 20 days. Then, eight-month-old Kunming female mice were treated with FLL under standard administration and diet as the aged group. In vitro, MC3T3-E1 cells stimulated by H2O2 were treated with FLL for 24 h. The micro-CT results showed that the modeling approach combining oxidative stress with a low calcium diet caused low conversion type osteoporosis in mice. FLL exerted a prominent effect on preventing osteoporosis by inhibiting oxidative stress, increasing bone mineral density (BMD), improving bone microstructure, and promoting osteoblast proliferation and osteoprotegerin (OPG) protein expression; however, FLL had no therapeutic effect on bone loss in aged mice. In conclusion, FLL showed outstanding anti-bone loss ability both in vivo and in vitro and could probably be developed as a prophylactic agent for osteoporosis.

Mild Idiopathic Infantile Hypercalcemia – Part 2: A Longitudinal Observational Study

Context Idiopathic Infantile Hypercalcemia (IIH) is an uncommon disorder with variable clinical features. The natural history and response to dietary calcium and vitamin D restriction in IIH remains unclear. Objective The aim of this study is to describe the clinical and biochemical response to dietary calcium and vitamin D restriction in a genetically characterized cohort of mild IIH. Methods This is a longitudinal, observational cohort study of 20 children with mild IIH monitored for a median of 21months. Biochemical measures, dietary assessment and yearly renal ultrasound results, since the time of diagnosis, were obtained and assessed prospectively every 4-6 months. Results Median age at initial diagnosis was 4·5 months. Median levels of serum calcium (2·82 mmol/l) and 1,25 (OH)2 D (192 pmol/l) were elevated whereas serum PTH was reduced (10 ng/l). Urinary calcium:creatinine ratio was elevated for some, but not all individuals (median 1·49 mmol/mmol). All patients who were managed with a low calcium diet showed an improvement in serum and urinary calcium measures, but the serum concentration of 1,25(OH)2D and 1,25(OH)2D/PTH ratio remained elevated. In 2 of the 11 subjects, renal calcification worsened. There were no differences in response between individuals with CYP24A1 or SLC34A1/A3 variants. Conclusion The clinical presentation of mild IIH is variable and dietary calcium and vitamin D restriction does not consistently normalize elevated 1,25(OH)2D concentrations or prevent worsening of renal calcification in all cases. Therapeutic options should target the defect in vitamin D metabolism.

Therapeutic Effect of IL1β Priming Tonsil Derived-Mesenchymal Stem Cells in Osteoporosis

Background: Stem cell therapies can be a new therapeutic strategy that may rebalance anabolic and anti-resorptive effects in osteoporosis patients. Tonsil-derived mesenchymal stem cells (TMSCs) can be an alternative therapeutic source for chronic degenerative diseases including osteoporosis. MSCs acquire immune regulatory function under the inflammatory cytokines. Since interleukin (IL) 1β is known to be one of inflammatory cytokines involved in osteoporosis progression, treatment of IL1β with TMSCs may enhance immunomodulatory function and therapeutic effects of TMSCs in osteoporosis. Methods: For IL1β priming, TMSCs were cultured in the presence of the medium containing IL1β for 1 day. Characteristics of IL1β priming TMSCs such as multipotent differentiation properties, anti-inflammatory potential, and suppression of osteoclast differentiation were assessed in vitro. For in vivo efficacy study, IL1β priming TMSCs were intravenously infused twice with ovariectomized (OVX) osteoporosis mouse model, and blood serum and bone parameters from micro computed tomography images were analyzed. Results: IL1β priming TMSCs had an enhanced osteogenic differentiation and secreted factors that regulate both osteoclastogenesis and osteoblastogenesis. IL1β priming TMSCs also suppressed proliferation of peripheral blood mononuclear cells (PBMCs) and decreased expression of Receptor activator of nuclear factor kappa-Β ligand (RANKL) in PHA-stimulated PBMCs. Furthermore, osteoclast specific genes such as Nuclear factor of activated T cells c1 (NFATc1) were effectively down regulated when co-cultured with IL1β priming TMSCs in RANKL induced osteoclasts. In OVX mice, IL1β priming TMSCs induced low level of serum RANKL/osteoprotegerin (OPG) ratio on the first day of the last administration. Four weeks after the last administration, bone mineral density and serum Gla-osteocalcin were increased in IL1β priming TMSC-treated OVX mice. Furthermore, bone formation and bone resorption markers that had been decreased in OVX mice with low calcium diet were recovered by infusion of IL1β priming TMSCs. Conclusion: IL1β priming can endow constant therapeutic efficacy with TMSCs, which may contribute to improve bone density and maintain bone homeostasis in postmenopausal osteoporosis. Therefore, IL1β priming TMSCs can be a new therapeutic option for treating postmenopausal osteoporosis.

Icariin protects against cage layer osteoporosis by intervening in steroid biosynthesis and glycerophospholipid metabolism

Cage layer osteoporosis (CLO) is a common bone metabolism disease in the breeding industry of China. However, effective prevention for CLO has not been developed. Icariin (ICA), the main bioactive component of the Chinese herb Epimedium, has been shown to have good therapeutic effects on bone-related diseases. In this study, the effects of ICA were further evaluated in a low-calcium diet-induced CLO, and a serum metabolomics assay was performed to understand the underlying mechanisms. A total of 144 31-wk-old Lohmann pink-shell laying hens were randomly allocated to 4 groups with 6 replicates of 6 hens per replicate. The 4 dietary treatment groups consisted of a basal diet (3.5% calcium), a low-calcium diet (2.0% calcium), and a low-calcium diet supplemented with 0.5 or 2.0 g/kg ICA. The results showed that ICA exerted good osteoprotective effects on low-calcium diet-induced CLO. ICA significantly increased femur bone mineral density, improved bone microstructure, decreased bone metabolic level, and upregulated mRNA expression of bone formation genes in femoral bone tissue. Serum untargeted metabolomics analysis showed that 8 metabolite levels were significantly changed after ICA treatment, including increased contents of 7-dehydrocholesterol, 7-oxocholesterol, desmosterol, PC (18:1(9Z)/18:1(9Z)), PS (18:0/18:1(9Z)), N,N-dimethylaniline and 2-hydroxy-butanoic acid and decreased N2,N2-dimethylguanosine. Metabolic pathway analysis based on the above 8 metabolites indicated that ICA mainly perturbed steroid biosynthesis and glycerophospholipid metabolism. These findings suggest that ICA can effectively prevent bone loss in low-calcium diet-induced CLO by mediating steroid biosynthesis and glycerophospholipid metabolism and provide new information for the regulation of bone metabolic diseases.

Dietary inulin increases Lactiplantibacillus plantarum strain Lp900 persistence in rats depending on the dietary-calcium level.

Synbiotics are food supplements that combine probiotics and prebiotics to synergistically elicit health benefits in the consumer. Lactiplantibacillus plantarum strains display high survival during transit through the mammalian gastrointestinal tract and were shown to have health-promoting properties. Growth on the fructose polysaccharide inulin is relatively uncommon in L. plantarum, and in this study we describe the plasmid-encoded β-fructosidase (FosE) with inulin hydrolyzing properties of L. plantarum strain Lp900. FosE contains an LPxTG-like motif involved in sortase-dependent cell-wall anchoring, but is also (partially) released in the culture supernatant. Additionally, we examined the effect of diet supplementation with inulin on the intestinal persistence of Lp900 in adult male Wistar rats in diets with distinct calcium levels. Inulin supplementation in high dietary calcium diets significantly increased the intestinal persistence of L. plantarum Lp900, whereas this effect was not observed upon inulin supplementation of the low-calcium diet. Moreover, intestinal persistence of L. plantarum Lp900 was determined when provided as a probiotic (by itself) or as a synbiotic (i.e., in an inulin suspension) in rats that were fed un-supplemented diets containing the different calcium levels, revealing that the synbiotic administration increased bacterial survival and led to higher abundance of L. plantarum Lp900 in rats, particularly in the low calcium diet context. Our findings demonstrate that inulin supplementation can significantly enhance the intestinal delivery of L. plantarum Lp900, but that this effect strongly depends on calcium levels in the diet. IMPORTANCE Synbiotics combine probiotics with prebiotics to synergistically elicit a health benefit in the consumer. Previous studies have shown that prebiotics can selectively stimulate the growth in the intestine of specific bacterial strains. In synbiotic supplementations the prebiotics constituent could increase the intestinal persistence and survival of accompanying probiotic strain(s) and/or modulate the endogenous host microbiota to contribute to the synergistic enhancement of the health-promoting effects of the synbiotic constituents. Our study establishes a profound effect of dietary calcium-dependent inulin supplementation on the intestinal persistence of inulin-utilizing L. plantarum Lp900 in rats. We also show that in rats on a low dietary calcium regime, the survival and intestinal abundance of L. plantarum Lp900 is significantly increased by administering it as an inulin-containing synbiotic. This study demonstrates that prebiotics can enhance the intestinal delivery of specific probiotics, and that the prebiotic effect is profoundly influenced by the calcium content of the diet.

Serum biomarkers of the calcium-deficient rats identified by metabolomics based on UPLC/Q-TOF MS/MS

Background We previously identified the urinary biomarkers to diagnose calcium deficiency and nutritional rickets by ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF MS/MS). To find biomarkers of calcium deficiency and further confirm these biomarkers in serum, we performed serum metabolomics analysis of calcium-deficient rats. Methods A calcium-deficient rat model was established with a low-calcium diet for 12 weeks. Serum metabolomics based UPLC/Q-TOF MS/MS and multivariate statistical analysis was performed to identify the alterations in metabolites associated with calcium deficiency in rats. Results Bone mineral density, serum parathyroid hormone and alkaline phosphatase were significantly decreased in the low-calcium diet group (LCG) compared to the normal calcium diet group (NCG). Serum metabolic-profiling analysis could definitively distinguish between the LCG and NCG and identified 24 calcium-deficient biomarkers. Three metabolites (indoxyl sulfate, phosphate, and taurine) of the 24 biomarkers were found in our previous urinary metabolomics study of rats with a calcium deficiency and nutritional rickets. The areas under the curve (AUCs) of these three biomarkers were greater than 0.8, and the combination of any two biomarkers was higher than 0.95. Conclusion Dietary calcium deficiency induced the alterations of metabolites in the serum of rats, and the three identified biomarkers had relatively high diagnostic values for calcium deficiency in rats.

Conservative Management of a Gestational Hypercalcemia Due to Primary Hyperparathyroidism with Lack of Complications

Introduction: Primary hyperparathyroidism (PHPT) is rare in pregnancy. PHPT and hypercalcemia are associated with negative maternofetal outcomes. Therefore, an early diagnosis and an adequate treatment are essential. Results: We describe the case of a pregnant woman, complaining of nausea, vomiting and weight loss. Diagnosis of gestational PHPT (GPHPT) was done based on elevated serum calcium and parathyroid hormone levels (3.4 mmol/L and 41.6 pmol/L). Neck ultrasound documented a nodule suggestive for enlarged parathyroid, whereas abdomen ultrasound revealed renal microlithiasis. Conservative treatment was started with oral hydration and low-calcium diet. Clinical and biochemical monitoring was weekly and multidisciplinary. Despite our suggestion, the patient refused parathyroidectomy in the second trimester. Additional intravenous fluid rehydration from the 15th to the 25th week of gestation ameliorated the symptoms rapidly, and reduced progressively calcium levels from the 23th week. At week 40, the woman gave birth to a healthy girl. At month 8 postpartum, calcemia and PTH were still elevated, and accompanied by osteoporosis and nephrocalcinosis. Surgery was accepted, and a parathyroid adenoma was removed. Conclusion: In absence of guidelines for GPHPT management, its treatment should be individualized. In our case, despite high calcium levels, a conservative treatment with strict monitoring led to positive outcome of pregnancy.

Serum biomarkers of the calcium-deficient rats identified by metabolomics based on UPLC/Q-TOF MS/MS

Background We previously identified the urinary biomarkers to diagnose calcium deficiency and nutritional rickets by ultra-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF MS/MS).To further confirm these biomarkers in vivo, we performed serum metabolomics analysis of calcium deficiency. Methods A calcium-deficient rat model was established with a low-calcium diet for 12 weeks. Serum-metabolomics-based UPLC/Q-TOF MS/MS and multivariate statistical analysis was performed to identify the alterations in metabolites associated with calcium deficiency in rats. Results Bone mineral density, serum parathyroid hormone and alkaline phosphatase were significantly decreased in the low-calcium diet group (LCG) compared to the normal calcium diet group (NCG). Serum metabolic-profiling analysis could definitively distinguish between the LCG and NCG andidentified25 calcium-deficient biomarkers. Three metabolites (indoxyl sulfate, phosphate, and taurine) of the 25 biomarkers were found in our previous urinary metabolomics study of rats with a calcium deficiency and nutritional rickets. The areas under the curve (AUCs) of these three biomarkers were greater than 0.8, and the combination of any two biomarkers was higher than 0.95. Conclusion Dietary calcium deficiency induced the alterations of metabolites in the serum of rats, and the three identified biomarkers had relatively high diagnostic values for calcium deficiency in rats.