Year : 2015 | Volume
: 141 | Issue : 3 | Page : 374--375
Phosphate and vitamin D in chronic kidney disease
Department of Nephrology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221 005, Uttar Pradesh, India
Department of Nephrology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221 005, Uttar Pradesh
|How to cite this article:|
Prakash J. Phosphate and vitamin D in chronic kidney disease.Indian J Med Res 2015;141:374-375
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Prakash J. Phosphate and vitamin D in chronic kidney disease. Indian J Med Res [serial online] 2015 [cited 2020 Jul 3 ];141:374-375
Available from: http://www.ijmr.org.in/text.asp?2015/141/3/374/156595
Phosphate and vitamin D in chronic kidney disease, M. S. Razzaque, editor (Karger, Basel, Switzerland) 2013. 154 pages. Price: US $ 233.00/CHF 198.00/EUR 165.00
This book describes in a comprehensive manner the metabolism of phosphate and vitamin D in patients with chronic kidney disease (CKD). It is an excellent compendium about recent development in the regulation of urinary phosphate excretion and the role of hyperphosphataemia in the development of ectopic calcification (vascular), cardiovascular diseases and secondary hyperparathyroidism in patients with CKD. The role of bone derived FGF23 and kidney derived klotho on vitamin D metabolism and Na/Pi co-transporters activities is well discussed in appropriate sections of the book.
Chapter 1, "Osteo - Renal - Cross-Talk and Phosphate Metabolism by the FGF23 - Klotho - System", introduces the significance of maintaining an adequate phosphate balance for sustenance of essential cellular and organ functions in human body with calcium regulatory factors (PTH and vitamin D) that control the phosphate metabolism. The authors introduce the prime highlight of this book, fibroblast growth factor (FGF23) - klotho system. This calcium independent factor plays an active role in the regulation of phosphate metabolism as well, with both bone derived FGF23 and kidney derived klotho system having a negative effect on vitamin D metabolism and Na/Pi cotransporter activities. The interaction of FGF23 and klotho through an unknown mechanism can suppress the activity of renal Na/Pi cotransporter system and thus increases urinary phosphate excretion. However, in the absence of klotho, FGF23 loses its phosphaturic effect.
Chapter 2 discusses the signalling propensity of extracellular phosphate. Phosphate is critical in various biological processes including membrane integrity, synthesis of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), enzyme metabolism and intracellular signalling.
Chapter 3 describes the functional diversity of alpha-klotho, which regulates mineral homeostasis of phosphate and calcium ions. Thus it is a new member of mineral regulating factors besides vitamin D and parathyroid hormone (PTH). The complexity of its regulation have also been well discussed in this chapter.
The relationship between chronic kidney disease (CKD) and klotho has been discussed in chapter 4. CKD is a state of endocrine and renal klotho deficiency which may contribute to CKD progression and complications of CKD including vascular calcification, cardiac hypertrophy and secondary hyperparathroydism. Klotho suppresses 1, α-hydroxylase in the kidney to regulate calcium metabolism. It appears that klotho protein administration may have potential therapeutic value in patients with CKD in future.
Chapter 5 discusses the role of nuclear receptors, specifically the liver X receptor (LXR) in CKD and its relationship with the Na/pi cotransporters. LXR agonists are one of the recent pharmaceutical approaches for disturbed phosphate homeostasis in CKD. The molecular mechanism of vascular calcification and various inducers and inhibitors of vascular calcification are described in chapter 6 entitled "Phosphate Toxicity and Vascular Mineralization". Lowering serum phosphate is associated with suppression of vascular calcification in patients with CKD despite high levels of serum calcium and 1, 25 (OH) 2 vitamin D. It means lowering serum phosphate concentration in CKD patients may minimize the risk of vascular calcification.
Chapters 7 and 8 entitled "Vitamin D and Type II Sodium-Dependent Phosphate Cotransporters" and "Vitamin D in Chronic Kidney Disease" describe the recent knowledge on the role of vitamin D in phosphate cotransporter and how vitamin D deficiency in CKD patients is involved in various clinical manifestations.
Chapter 9 entitled "Parathyroid Function in Chronic Kidney Disease: Role of FGF23 - Klotho Axis" describes recent observations regarding the role of FGF23/klotho system in the genesis of secondary hyperparathyroidism, and finally chapter 10 discusses the approach of using salivary phosphate levels as a biomarker for obesity.
Overall, this is a comprehensive book describing the various aspects of recent advances and molecular basis of the mechanism of secondary hyperparathyroidism, vascular calcification, and cardiac hypertrophy in patients with CKD with special reference to the role of phosphate, vitamin D and klotho protein in these patients. All chapters are written in a lucid and clinically relevant manner. This book will be helpful for physicians, nephrologists, biochemists, physiologists and researchers working in the respective fields of experimental chronic kidney diseases.