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.

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.