Increased calcium absorption from synthetic stable amorphous calcium carbonate: double-blind randomized crossover clinical trial in postmenopausal women

Amorphous Calcium Carbonate Enhances Fracture Healing in a Rat Fracture Model

Background: Delayed and failed fracture repair and bone healing remain significant public health issues. Dietary supplements serve as a safe, inexpensive, and non-surgical means to aid in different stages of fracture repair. Studies have shown that amorphous calcium carbonate (ACC) is absorbed 2 to 4.6 times more than crystalline calcium carbonate in humans. Objectives: In the present study, we assessed the efficacy of ACC on femoral fracture healing in a male Wistar rat model. Methods: Eighty male Wistar rats were randomly divided into five groups (n = six per group): sham, fracture + water, fracture + 0.5× (206 mg/kg) ACC, fracture + 1× ACC (412 mg/kg), and fracture + 1.5× (618 mg/kg) ACC, where ACC refers to the equivalent supplemental dose of ACC for humans. A 21-gauge needle was placed in the left femoral shaft, and we then waited for three weeks. After three weeks, the sham group of rats was left without fractures, while the remaining animals had their left mid-femur fractured with an impactor, followed by treatment with different doses of oral ACC for three weeks. Weight-bearing capacity, microcomputed tomography, and serum biomarkers were evaluated weekly. After three weeks, the rats were sacrificed, and their femur bones were isolated to conduct an evaluation of biomechanical strength and histological analysis. Results: Weight-bearing tests showed that treatment with ACC at all the tested doses led to a significant increase in weight-bearing capacity compared to the controls. In addition, microcomputed tomography and histological studies revealed that ACC treatment improved callus formation dose-dependently. Moreover, biomechanical strength was improved in a dose-dependent fashion in ACC-treated rats compared to the controls. In addition, supplementation with ACC significantly lowered bone formation and resorption marker levels two-three weeks post-fracture induction, indicating accelerated fracture recovery. Conclusions: Our preliminary data demonstrate that ACC supplementation improves fracture healing, with ACC-supplemented rats healing in a shorter time than control rats.

Amorphous calcium carbonate as a novel potential treatment for osteoarthritis in dogs: a pilot clinical study

Background

Amorphous calcium carbonate (ACC) is a potential new treatment for canine osteoarthritis (OA) with novel mechanisms based on local pH modulation and targeting bone remodeling, inflammation, and pain. The aim of this pilot exploratory clinical study was to obtain initial data on the potential efficacy and safety of ACC in OA dogs and to determine if further investigation was appropriate using similar assessment methods.

Materials and methods

In this prospective, randomized, double-blind, controlled pilot study, 41 client-owned dogs were allocated in a 2:1 ratio to ACC: placebo given orally for 56 days. Efficacy assessments included improvements in pain and mobility using owner questionnaires [Canine Brief Pain Inventory (CBPI), Client Specific Outcome Measure (CSOM), and Veterinary Orthopedic Scores (VOS)]. Safety in the study population was monitored by veterinary examinations, clinical pathology, and adverse events.

Results

Fifty-three dogs were screened, of which 41 enrolled and served for the safety assessment. Thirty-six dogs were found evaluable for initial efficacy assessment. Three dogs given placebo (21.4%) and one given ACC (4.5%) were removed before day 56 due to owner-perceived pain and were considered treatment failures. There were no serious adverse events or clinically significant treatment-related effects in the study. Overall, ACC was found safe in the small study population. On day 56, proportionally more ACC than placebo dogs were treatment successes based on CBPI (45.5% vs. 21.4%) and CSOM (63.6% vs. 30.8%, respectively); however, these differences were not statistically significant (p = 0.15 and 0.06, respectively). On day 56, within the ACC group but not the placebo group, the CBPI, CSOM, and VOS assessments were lower compared to day 0 and day 14 (p < 0.05).

Limitations

The relatively small number of dogs limited the statistical power of the pilot study in evaluating the efficacy and safety of ACC.

Conclusion

Study results support the conduct of larger, appropriately powered studies using similar assessments to confirm whether ACC may be a safe and effective treatment for OA in dogs.

Amorphous calcium carbonate enhances osteogenic differentiation and myotube formation of human bone marrow derived mesenchymal stem cells and primary skeletal muscle cells under microgravity conditions

Astronauts are exposed to severely stressful physiological conditions due to microgravity and increased space radiation. Space environment affects every organ and cell in the body and the significant adverse effects of long-term weightlessness include muscle atrophy and deterioration of the skeleton (spaceflight osteopenia). Amorphous Calcium Carbonate (ACC) emerges as a promising candidate for prevention of these effects, owing to its unique physicochemical properties and its potential to address the intricately linked nature of bone-muscle crosstalk. Reported here are two studies carried out on the International Space Station (ISS). The first, performed in 2018 as a part of the Ramon-Spacelab project, was a preliminary experiment, in which stromal murine cells were differentiated into osteoblasts when ACC was added to the culture medium. A parallel experiment was done on Earth as a control. The second study was part of Axiom-1's Rakia project mission launched to the ISS on 2022 utilizing organ-on-a-chip methodology with a specially designed autonomous module. In this experiment, human bone-marrow derived mesenchymal stem cells (hBM-MSCs) and human primary muscle cells were cultured in the presence or absence of ACC, in duplicates. The results showed that ACC enhanced differentiation of human primary skeletal muscle cells into myotubes. Similarly, hBM-MSCs were differentiated significantly better into osteocytes in the presence of ACC leading to increased calcium deposits. The results, combined with previous data, support the use of ACC as an advantageous supplement for preventing muscle and bone deterioration in outer space conditions, facilitating extended extraterrestrial voyages and colonization.

Assessing Performance of Contemporary Plant-Based Diets against the UK Dietary Guidelines: Findings from the Feeding the Future (FEED) Study

Uncertainty remains about the composition of contemporary plant-based diets and whether they provide recommended nutrient intakes. We established Feeding the Future (FEED), an up-to-date online cohort of UK adults following different plant-based diets and diets containing meat and fish. We recruited 6342 participants aged 18-99 [omnivores (1562), flexitarians (1349), pescatarians (568), vegetarians (1292), and vegans (1571)] between February 2022 and December 2023, and measured diet using a food frequency questionnaire and free text. We compared personal characteristics and dietary intakes between diet groups and assessed compliance with dietary guidelines. Most participants met UK dietary recommendations for fruit and vegetables, sodium, and protein, although protein intakes were lowest among vegetarians and vegans. Omnivores did not meet the fibre recommendation and only vegans met the saturated fat recommendation. All diet groups exceeded the free sugars recommendation. Higher proportions of vegetarians and vegans were below the estimated average requirements (EARs) for zinc, iodine, selenium, and, in vegans, vitamins A and B12, whereas calcium intakes were similar across the diet groups. People following plant-based diets showed good compliance with most dietary targets, and their risk for inadequate intakes of certain nutrients might be mitigated by improved dietary choices and/or food fortification.

Amorphous Calcium Carbonate from Plants Can Promote Bone Growth in Growing Rats

OBJECTIVES

This study aimed to investigate the effect of amorphous calcium carbonate (ACC) supplementation on bone growth in growing rats.

METHODS

We used 3-week-old male Wistar rats to simulate childhood and adolescent growth stages. Rats were divided into four groups as follows: a control group (C), a low-dose group (L, 20.65 mg/kg body weight (BW) ACC), a medium-dose group (M, 206.5 mg/kg BW ACC), and a high-dose group (H, 413 mg/kg BW ACC) administered by gavage. Body length (BL) and BW were measured weekly. The bone mineral density (BMD) of two lumbar vertebrae (L3 and L4) and the left femur were analyzed by micro-computed tomography (μCT) at 0, 4, 8, and 12 weeks. At the end of 12 weeks, the rats were sacrificed. After that, blood samples were collected from the abdominal aorta. Femurs and tibias were collected and weighed, and their lengths were measured. Then, bone samples were used to perform histopathological and histomorphometric analyses.

RESULTS

It showed that ACC supplementation in growing rats increased the trabecular bone thickness and serum bone formation biomarkers. Furthermore, high-dose ACC decreased serum bone resorption biomarkers and increased BMD.

CONCLUSIONS

ACC supplementation can enhance osteoblast metabolism and inhibit osteoclast metabolism, resulting in a higher bone formation rate compared to bone resorption. This led to increased trabecular bone thickness, a higher BMD, and supported bone growth.

Unlocking the potential of amorphous calcium carbonate: A star ascending in the realm of biomedical application

Calcium-based biomaterials have been intensively studied in the field of drug delivery owing to their excellent biocompatibility and biodegradability. Calcium-based materials can also deliver contrast agents, which can enhance real-time imaging and exert a Ca2+-interfering therapeutic effect. Based on these characteristics, amorphous calcium carbonate (ACC), as a brunch of calcium-based biomaterials, has the potential to become a widely used biomaterial. Highly functional ACC can be either discovered in natural organisms or obtained by chemical synthesis However, the standalone presence of ACC is unstable in vivo. Additives are required to be used as stabilizers or core-shell structures formed by permeable layers or lipids with modified molecules constructed to maintain the stability of ACC until the ACC carrier reaches its destination. ACC has high chemical instability and can produce biocompatible products when exposed to an acidic condition in vivo, such as Ca2+ with an immune-regulating ability and CO2 with an imaging-enhancing ability. Owing to these characteristics, ACC has been studied for self-sacrificing templates of carrier construction, targeted delivery of oncology drugs, immunomodulation, tumor imaging, tissue engineering, and calcium supplementation. Emphasis in this paper has been placed on the origin, structural features, and multiple applications of ACC. Meanwhile, ACC faces many challenges in clinical translation, and long-term basic research is required to overcome these challenges. We hope that this study will contribute to future innovative research on ACC.

The effect of amorphous calcium carbonate as a culture media supplement on embryonic development of murine sibling embryos

PURPOSE

The aim of this study was to compare the addition in culture media of stabilized amorphous calcium carbonate (ACC) versus calcium chloride (CaCl2) or calcium carbonate in crystalline form (CCC) on growth rates among sibling mouse embryos.

METHODS

We evaluated the effect of different ACC concentrations on the rates of embryo compaction at 60 h, blastocyst rate at 84 h and percentage of fully hatched at 108 h following hCG injection. As ACC is stabilized by tripolyphosphate (TPP), we also evaluated the addition of TPP alone to the culture media. Finally, we compared supplemented ACC culture media to one-step SAGE and Irvine cleavage media.

RESULTS

The results revealed that ACC accelerates the compaction and blastocyst rates, as well as the percentage of fully hatched embryos in a dose-dependent manner, with an increased positive effect at 2.5 mM. The magnitude of the effect for ACC-supplemented media on the embryo developmental rate was between 30 to 40% (p < 0.01) faster for each stage, compared to both SAGE and Irvine one-step standard media. Embryos cultured with SAGE or Irvine media with or without supplementation of CaCl2 or CCC, did not produce the same improvements as observed with ACC.

CONCLUSION

In conclusion, the ACC demonstrates a rapid modulation effect for restoring media optimal pH. ACC can inhibit cathepsin B activity during in vitro culture of fibroblast cells. The beneficial impact of ACC on cleavage mouse embryos is likely due to an improved buffering effect causing slower pH media variations, which may enhance quality and implantation potential of embryos following in vitro culture.

Amorphous Calcium Carbonate Shows Anti-Cancer Properties That are Attributed to Its Buffering Capacity

AIM

Amorphous calcium carbonate (ACC) is a non-crystalline form of calcium carbonate, and it is composed of aggregated nano-size primary particles. Here, we evaluated its anti-cancer effect postulated relative to its buffering capabilities in lung cancer.

METHODS

Tumors were evaluated in vivo using the Lewis lung carcinoma (LLC) mouse cell line and A549 human lung cancer carcinoma cell line. LLC and A549 cells were injected subcutaneously into the right hind leg of mice. Treatments (ACC, cisplatin, vehicle, and ACC with cisplatin, all given via daily IP injections) started once tumors reached a measurable size. Treatments were carried out for 14 days in the LLC model and for 22 and 24 days in the xenograft model (two experiments). LLC tumors were resected from ACC at the end of the study, and vehicle groups were evaluated for cathepsin B activity. Differential gene expression was carried out on A549 cells following 8 weeks of in vitro culture in the presence or absence of ACC in a culture medium.

RESULTS

The ACC treatment decelerated tumor growth rates in both models. When tumor volumes were compared on the last day of each study, the ACC-treated animal tumor volume was reduced by 44.83% compared to vehicle-treated animals in the LLC model. In the xenograft model, the tumor volume was reduced by 51.6% in ACC-treated animals compared to vehicle-treated animals. A more substantial reduction of 74.75% occurred in the combined treatment of ACC and cisplatin compared to the vehicle (carried out only in the LLC model). Cathepsin B activity was significantly reduced in ACC-treated LLC tumors compared to control tumors. Differential gene expression results showed a shift towards anti-tumorigenic pathways in the ACC-treated A549 cells.

CONCLUSION

This study supports the ACC anti-malignant buffering hypothesis by demonstrating decelerated tumor growth, reduced cathepsin B activity, and altered gene expressions to produce anti-cancerous effects.

Bioavailability of calcium in an enriched postbiotic system compared to calcium citrate in healthy postmenopausal females; A randomized, double-blind, comparator-controlled, crossover study

Introduction

Bioavailability of calcium is an important consideration when designing supplements for achieving adequate calcium intake, mainly in high-risk, and aged populations. Alternative supplementation strategies may be able to circumvent absorption issues commonly seen with calcium supplements. The objective of this study was to assess the bioavailability of a single serving of two calcium formulations vs. comparator product in healthy postmenopausal women.

Methods

A total of 24 participants between 45 and 65 years were enrolled in a randomized, double-blind, three-phase, crossover study, with a 7-day washout period between phases. The bioavailability of calcium from calcium-carrying Saccharomyces cerevisiae (Ca-SC) or calcium-carrying Lactobacillus (Ca-LAB) in the form of postbiotic products versus calcium citrate, a conventional salt-based calcium supplement, was determined. Each product provided 630 mg of calcium and 400 IU of vitamin D3. After a 14-h (overnight) fast followed by a single dose of product with a standard low-calcium breakfast, both serum and urine calcium concentrations were assessed for up to 8 and 24 h, respectively.

Results

Ca-LAB resulted in greater calcium bioavailability, demonstrated by significantly higher area under the curve and peak concentration both in blood and urine, and total calcium mass excreted in urine. The bioavailability of calcium was similar for Ca-SC and calcium citrate except for the peak concentration value that was significantly higher for calcium citrate. Both Ca-LAB and Ca-SC were well tolerated with no significant difference in adverse events between the products during the study.

Discussion

These findings suggest that calcium enriched in a Lactobacillus-based postbiotic system is associated with higher levels of bioavailability as compared to calcium citrate, while a calcium-enriched yeast-based postbiotic does not influence calcium absorption.

The Effects of Amorphous Calcium Carbonate (ACC) Supplementation on Resistance Exercise Performance in Women

The effects of 9 weeks of amorphous calcium carbonate (ACC) supplementation (1000 mg/day) and resistance exercise training (RT) on one repetition maximum (1-RM) values were tested. Thirty-one women (33.1 ± 7.3 y) were randomly assigned into a supplement (ACC, n = 14) or a placebo (PL, n = 17) group. On day 1 and following 9 weeks of intervention, the participants underwent anthropometric measurements and filled out a food frequency questionnaire (FFQ) and sports injuries questionnaires. 1-RM values were measured for the back squat and bench press exercises. All the participants significantly (p = 0.01) improved their mean back squat and bench press 1-RM values (time effect). While no between-group difference was observed in the bench press 1-RM values, the ACC groups' mean post-pre bench press 1-RM differences (Δ1-RM) were significantly higher than in the PL group, expressed in kg (p = 0.049), per body mass (p = 0.042), or per lean body mass (p = 0.035). No significant interaction was observed for time X group effect (p = 0.421). No differences (within- or between-groups) were observed in the anthropometric values or in the questionnaires' results. ACC supplementation revealed an ergogenic effect by augmenting the improvement of maximum amount generated force, which can possibly be attributed to the calcium and/or the carbonate components.

Examination of Amorphous Calcium Carbonate on the Inflammatory and Muscle Damage Response in Experienced Resistance Trained Individuals

The effect of 3 weeks of amorphous calcium carbonate (ACC) supplementation (2000 mg per day) was examined on the recovery response to resistance exercise. Thirty men were randomized into a supplement (ACC) or placebo (PL) group. Following supplementation, participants performed six sets of 10 repetitions in the bench press (BP) and incline BP exercises, using 80% of maximal strength. Participants returned 24 (T4) and 48 h (T5) later and performed six sets of the BP exercise. Significant decreases in the number of repetitions (p < 0.001), peak power (p < 0.001), and mean power (p = 0.009) were noted over time, but no significant interactions were observed (p > 0.05). Magnitude-based inference analysis (MBI) indicated that the change in repetitions was possibly beneficial for ACC at T4 and likely beneficial at T5. No significant interaction was noted for general soreness (p = 0.452), but a trend toward an interaction was observed in upper body soreness (p = 0.089). Confidence intervals for mean percent change scores indicated significant differences between the groups at T4 and T5, and MBI analysis indicated that ACC was very likely or likely to be beneficial for reducing soreness at those time points. In conclusion, ACC supplementation may have a potential beneficial effect in attenuating the decline in performance, which is possibly due to the carbonate component.

Evaluation of an Ionic Calcium Fiber Supplement and Its Impact on Bone Health Preservation in a Dietary Calcium Deficiency Mice Model

Ionic calcium can help in the prevention of the process of osseous decalcification. This study aimed to evaluate the physicochemical properties and toxic effects of ionic calcium-fiber supplement (ICa+) and its impact on bone health preservation in mice C57/BL6 fed a calcium-deficient diet. Physicochemical properties include FTIR, apparent calcium solubility estimated by the calcium ratio obtained by ionization chromatography and atomic absorption. In vitro genotoxicity and cytotoxicity of the ICa+ were assessed. Twenty-five 7-week-old C57/BL6 mice were fed calcium-free diet (CFD) or CFD plus CaCO3 (1.33 mg Ca) or CFD plus ICa+ (1.33-6.66 mg Ca) for six weeks. After that, bone mass and microstructure parameters were assessed. Histological staining was performed to determine calcium deposits. ICa+ (100%) exhibited an apparent calcium solubility higher than CaCO3 (12.3%). ICa+ showed no cytotoxic and genotoxic in vitro activities. Histomorphometry analysis showed that the ICa+ treated group displayed a higher trabecular number than the trabecular space. Also, the ratio BV/TV was increased compared with all treatments. Ionic calcium-fiber supplementation prevents bone deterioration compared to mice fed a calcium-deficient diet.

Ingestion of gastrolith mineralized matrix increases bone volume and tissue volume in mouse long bone fracture model

Purpose

Fracture healing often requires extended convalescence as the bony fragments consolidate into restored viable tissue for load-bearing. Development of interventions to improve healing remains a priority for orthopaedic research. The goal of this study was to evaluate the ability of a naturally occurring matrix of amorphous calcium carbonate to affect fracture healing in an uninstrumented long bone model.

Methods

Complete transverse fracture was induced in the fibula of mature mice, followed by daily gavage of crushed gastrolith from crayfish at doses of 0 (control), 1 (1 MG), and 5 (5 MG) mg/kg. At Day 17, bones and sera were harvested.

Results

Morphologically, the 1 MG treated group had greater bone volume (BV), and both 1 MG and 5 MG had greater tissue volume (TV) than control (p < 0.05), as determined by μCT; BV/TV and mineral density did not yield a statistical difference. Histologically, regional variations in mineralized matrix were evident in all specimens, indicating a broad continuum of healing within the callus. Among serum proteins, bone-specific alkaline phosphatase, indicative of active mineralization, was greater in 5 MG than control (p < 0.05). Sclerostin, an inhibitor of osteogenesis, was lower in 5 MG than control (p < 0.05), also suggestive of enhanced healing.

Conclusions

An increase in bone volume, tissue volume and cellular signaling for osteogenesis at 17 days following fibula fracture in this mouse model suggests that gastrolith treatment holds potential for improving fracture healing. Further study at subsequent time points is warranted to determine the extent to which the increase in callus size with gastrolith treatment may accelerate restoration of tissue integrity.

Management of Hypoparathyroidism: Present and Future

CONTEXT

Conventional management of hypoparathyroidism has focused upon maintaining the serum calcium with oral calcium and active vitamin D, often requiring high doses and giving rise to concerns about long-term consequences including renal and brain calcifications. Replacement therapy with PTH has recently become available. This paper summarizes the results of the findings and recommendations of the Working Group on Management of Hypoparathyroidism.

EVIDENCE ACQUISITION

Contributing authors reviewed the literature regarding physiology, pathophysiology, and nutritional aspects of hypoparathyroidism, management of acute hypocalcemia, clinical aspects of chronic management, and replacement therapy of hypoparathyroidism with PTH peptides. PubMed and other literature search engines were utilized.

EVIDENCE SYNTHESIS

Under normal circumstances, interactions between PTH and active vitamin D along with the dynamics of calcium and phosphorus absorption, renal tubular handing of those ions, and skeletal responsiveness help to maintain calcium homeostasis and skeletal health. In the absence of PTH, the gastrointestinal tract, kidneys, and skeleton are all affected, leading to hypocalcemia, hyperphosphatemia, reduced bone remodeling, and an inability to conserve filtered calcium. Acute hypocalcemia can be a medical emergency presenting with neuromuscular irritability. The recent availability of recombinant human PTH (1-84) has given hope that management of hypoparathyroidism with the missing hormone in this disorder will provide better control and reduced needs for calcium and vitamin D.

CONCLUSIONS

Hypoparathyroidism is associated with abnormal calcium and skeletal homeostasis. Control with calcium and active vitamin D can be a challenge. The availability of PTH (1-84) replacement therapy may usher new opportunities for better control with reduced supplementation requirements.

Calcium Carbonate

Calcium carbonate is a chemical compound with the formula CaCO3 formed by three main elements: carbon, oxygen, and calcium. It is a common substance found in rocks in all parts of the world (most notably as limestone), and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. CaCO3 exists in different polymorphs, each with specific stability that depends on a diversity of variables.