[Fibroblast Growth Factor 23-Klotho: a new axis of phosphate balance control].
ABSTRACT The kidney is a key player of phosphate balance, it determines serum phosphate levels by coupling phosphate reabsorption in the renal proximal tubule, calcitriol synthesis and consequently intestinal -phosphate absorption. The identification of fibroblast growth factor 23 (FGF23) as a hormone regulating phosphate and calcitriol metabolism has unveiled the mechanisms that coordinate these renal proximal tubule functions. A bone-kidney axis has emerged that controls bone mineralization. Animal model studies have improved our understanding of phosphate homeostasis and revealed the role of the Klotho protein, which is mandatory to FGF23 action. In this review, we detail FGF23 and Klotho implication in physiology and in genetic or acquired disorders. Phosphate ion is involved in vascular and soft tissue calcification and is important for cell proliferation. Disorders of FGF23-klotho axis alter life span and are involved in senescence.
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ABSTRACT: The link between vascular calcification (VC) and increased mortality is now well established. Over time, as clinical importance of this phenomenon has begun to be fully considered, scientists have highlighted more and more physiopathological mechanisms and signaling pathways that underlie VC. Several conditions such as diabetes, dyslipidemia and renal diseases are undoubtelly identified as predisposing factors. But even if the process is better understood, many questions still remain unanswered. This review briefly develops the various theories that attempt to explain mineralization genesis. Nonetheless, the main purpose of the article is to provide a profile of the various existing biomarkers of VC. Indeed, in the past years, a lot of inhibitors and promoters, which form a dense and interconnected network, were identified. Given importance to assess and control mineralization process, a focusing on accumulated knowledge of each marker seemed to be necessary. Therefore, we tried to define their respective role in the physiopathology and how they can contribute to calcification risk assessment. Among these, Klotho / fibroblast growth factor-23, fetuin-A, Matrix Gla protein, Bone morphogenetic protein-2, osteoprotegerin, osteopontin, osteonectin, osteocalcin, pyrophosphate and sclerostin are specifically discussed.09/2014;
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ABSTRACT: Nowadays, vascular calcification is considered as an actively regulated and complex process that remains not completely understood.•A large variety of conditions can modulate vascular microenvironment composition, such as bone turnover, inflammation, vitamin D status or even oxidative stress.•Inhibitors and promoters of vascular calcification form a dense and interconnected network.•It is essential to define the role of each biomarker in the physiopathology and to determine how they can contribute to calcification risk assessment.Clinica Chimica Acta. 01/2015; 438.