Potassium citrate prevents increased osteoclastogenesis resulting from acidic conditions: Implication for the treatment of postmenopausal bone loss.

Donatella Granchi, Elena Torreggiani, Annamaria Massa, Renata Caudarella, Gemma Di Pompo, Nicola Baldini

Research output: Contribution to journalArticle

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Abstract

The extracellular acidic milieu in bones results in activation of osteoclasts (OC) and inhibition of osteoblasts (OB) causing a net loss of calcium from the skeleton and the deterioration of bone microarchitecture. Alkalinization through supplementation with potassium citrate (K citrate) has been proposed to limit the osteopenia progression, even though its pharmacological activity in bone microenvironment is not well defined. We evaluated if K citrate was able to prevent the adverse effects that acidic milieu induces on bone cells. OC and OB were maintained in neutral (pH 7.4) versus acidic (pH 6.9) culture medium, and treated with different K citrate concentrations. We evaluated the OC differentiation at seven days, by counting of multinucleated cells expressing tartrate-resistant acid phosphatase, and the activity of mature OC at 14 days, by quantifying of collagen degradation. To evaluate the effects on OB, we analyzed proliferation, mineralization, and expression of bone-related genes. We found that the low pH increased OC differentiation and activity and decreased OB function. The osteoclastogenesis was also promoted by RANKL concentrations ineffective at pH 7.4. Non-cytotoxic K citrate concentrations were not sufficient to steadily neutralize the acidic medium, but a) inhibited the osteoclastogenesis, the collagen degradation, and the expression of genes involved in RANKL-mediated OC differentiation, b) enhanced OB proliferation and alkaline phosphatase expression, whereas it did not affect the in vitro mineralization, and c) were effective also in OC cultures resistant to alendronate, i.e. the positive control of osteoclastogenesis inhibition. In conclusion, K citrate prevents the increase in OC activity induced by the acidic microenvironment, and the effect does not depend exclusively on its alkalizing capacity. These data provide the biological basis for the use of K citrate in preventing the osteopenia progression resulting from low-grade acidosis.
Original languageEnglish
Pages (from-to)1-22
Number of pages22
JournalPLoS One
Volume12
Issue number7
DOIs
Publication statusPublished - 2017

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Potassium Citrate
Postmenopausal Osteoporosis
osteoclasts
Osteoclasts
Osteogenesis
citrates
Bone
potassium
bones
Citric Acid
osteoblasts
Osteoblasts
osteopenia
Bone and Bones
Metabolic Bone Diseases
collagen
mineralization
Collagen
Genes
Alendronate

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Potassium citrate prevents increased osteoclastogenesis resulting from acidic conditions: Implication for the treatment of postmenopausal bone loss. / Granchi, Donatella; Torreggiani, Elena; Massa, Annamaria; Caudarella, Renata; Di Pompo, Gemma; Baldini, Nicola.

In: PLoS One, Vol. 12, No. 7, 2017, p. 1-22.

Research output: Contribution to journalArticle

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