The Effects of Sodium Phosphate Supplementation on the Cardiorespiratory System and Gross Efficiency during Exercise under Hypoxia in Male Cyclists: A Randomized, Placebo-Controlled, Cross-Over Study

The main aim of this study was to evaluate the effects of six days of tri-sodium phosphate (SP) supplementation on the cardiorespiratory system and gross efficiency (GE) during exercise under hypoxia in cyclists. Twenty trained male cyclists received SP (50 mg·kg−1 of fat-free mass/day) or placebo for six days in a randomized, cross-over study, with a three-week washout period between supplementation phases. Before and after each supplementation phase, the subjects performed an incremental exercise test to exhaustion under normobaric hypoxia (FiO2 = 16%, ~2500 m). It was observed that short-term SP supplementation led to a decrease in heart rate, an increase in stroke volume, and an improvement in oxygen pulse (VO2/HR) during low and moderate-intensity exercise under hypoxia. These changes were accompanied by an increase in the serum inorganic phosphate level by 8.7% (p < 0.05). No significant changes were observed in serum calcium levels. GE at a given workload did not change significantly after SP supplementation. These results indicated that SP promotes improvements in the efficiency of the cardiorespiratory system during exercise in a hypoxic environment. Thus, SP supplementation may be beneficial for endurance exercise in hypoxia.

The Metabolic Bone Disease X-linked Hypophosphatemia: Case Presentation, Pathophysiology and Pharmacology

The authors present a stereotypical case presentation of X-linked hypophosphatemia (XLH) and provide a review of the pathophysiology and related pharmacology of this condition, primarily focusing on the FDA-approved medication burosumab. XLH is a renal phosphate wasting disorder caused by loss of function mutations in the PHEX gene (phosphate-regulating gene with homologies to endopeptidases on the X chromosome). Typical biochemical findings include elevated serum levels of bioactive/intact fibroblast growth factor 23 (FGF23) which lead to (i) low serum phosphate levels, (ii) increased fractional excretion of phosphate, and (iii) inappropriately low or normal 1,25-dihydroxyvitamin D (1,25-vitD). XLH is the most common form of heritable rickets and short stature in patients with XLH is due to chronic hypophosphatemia. Additionally, patients with XLH experience joint pain and osteoarthritis from skeletal deformities, fractures, enthesopathy, spinal stenosis, and hearing loss. Historically, treatment for XLH was limited to oral phosphate supplementation, active vitamin D supplementation, and surgical intervention for cases of severe bowed legs. In 2018, the United States Food and Drug Administration (FDA) approved burosumab for the treatment of XLH and this medication has demonstrated substantial benefit compared with conventional therapy. Burosumab binds circulating intact FGF23 and blocks its biological effects in target tissues, resulting in increased serum inorganic phosphate (Pi) concentrations and increased conversion of inactive vitamin D to active 1,25-vitD.

The Metabolic Bone Disease X-Linked Hypophosphatemia: Case Presentation, Pathophysiology and Pharmacology

The authors present a stereotypical case presentation of x-linked hypophosphatemia (XLH) and provide a review of the pathophysiology and related pharmacology of this condition, primarily focusing on the FDA-approved medication burosumab. XLH is a renal phosphate wasting disorder caused by loss of function mutations in the PHEX gene (phosphate-regulating gene with homologies to endopeptidases on the X chromosome). Typical biochemical findings include elevated serum levels of bioactive/intact Fibroblast Growth Factor 23 (FGF23) which lead to i) low serum phosphate levels, ii) increased fractional excretion of phosphorus, and iii) inappropriately low or normal 1,25-dihydroxyvitamin D (1,25-vitD). XLH is the most common form of heritable rickets and short stature in XLH patients is due to chronic hypophosphatemia. Additionally, XLH patients experience joint pain and osteoarthritis from skeletal deformities, fractures, enthesopathy, spinal stenosis, and hearing loss. Historically, treatment for XLH was limited to oral phosphate supplementation, active vitamin D supplementation, and surgical intervention for cases of severe bowed legs. In 2018, the United States Food and Drug Administration’s (FDA) approved burosumab for the treatment of XLH and this medication has demonstrated substantial benefit compared with conventional therapy. Burosumab binds circulating intact FGF23 and blocks its biological effects in target tissues, resulting in increased serum inorganic phosphate (Pi) concentrations and increased conversion of inactive vitamin D to active 1,25-vitD.

PSEUDOHYPOPHOSPHATEMIA IN A PATIENT WITH MULTIPLE MYELOMA

Objective: To discuss the diagnosis and management of paraprotein interference in the setting of multiple myeloma (MM). Methods: We discuss the evaluation of hypophosphatemia in a patient with MM and present a review of the relevant literature. Results: Our patient, who had a history of MM, was found to have persistently undetectable serum phosphate which did not respond to aggressive phosphate replacement. His clinical condition was not consistent with severe phosphate depletion and hence paraprotein interference secondary to MM was suspected. Re-analyzation of samples on a different machine showed normal serum inorganic phosphate levels. Conclusion: Paraprotein interference from MM causing pseudohypophosphatemia can be overlooked and lead to unnecessary treatment. Recognition of this phenomenon is important to all clinicians, especially in light of potential complications of unnecessary treatment.

Effects of combined ethanol extract of Funtumia africana and Abutilon mauritianum leaves on prostate biomarkers and serum mineral levels in prostatic hyperplasia induced male rats

Introduction: Benign prostatic hyperplasia (BPH) is a prostate disorder in ageing males that negatively affects the quality of life and requires multidimensional approaches to ameliorate its adverse health effects. Objectives: This study evaluated the effects of combined ethanol extract of Funtumia africana and Abutilon mauritianum leaves on the prostate biomarkers, serum mineral levels and prostate histomorphology of BPH induced rats. Materials and Methods: Thirty-six male Wistar albino rats randomly distributed into 5 groups containing 6 rats each was used for this study. Group 1 served as the normal control rats without BPH induction while groups 2–5 were BPH induced rats that served as BPH control (untreated), finasteride control, and BPH induced treated with 200 and 600 mg/kg/d of the combined ethanol extract of F. africana and A. mauritianum leaves respectively. BPH was induced in the rats by subcutaneous injection of 5 mg/kg/d of testosterone propionate injection and treatment followed 1h after the induction for 28 consecutive days. All the biochemical analyses and prostate histological examinations were carried out using standard methods. Results: BPH induction significantly elevated serum prostatic acid phosphatase activities and serum prostate-specific antigen (PSA) concentrations in the BPH control rats relative to the normal control. The BPH induction caused significant (P<0.05) reductions in the serum levels of calcium and selenium levels and significantly increased the serum inorganic phosphate concentration in the BPH control when compared with the normal control. Treatment with the combined extract significantly (P<0.05) increased the serum zinc, calcium, copper, iron and inorganic phosphate and significantly reduced serum selenium level when compared with the BPH control. The combined extract further significant (P<0.0) reduced the serum prostatic acid phosphatase activities and PSA level relative to the BPH control. The BPH control showed severe prostate histomorphological alterations consistent with BPH which were largely reduced to mild alterations in combined extract-treated BPH induced rats. Conclusion: This study revealed that the combined ethanol extract of F. africana and A. mauritianum leaves positively regulate the serum mineral levels, serum prostatic acid phosphatase activities, PSA levels and improves prostate histomorphology BPH induced rats.

Diabetes, Diabetic Complications, and Phosphate Toxicity: A Scoping Review

This article presents a scoping review and synthesis of research findings investigating the toxic cellular accumulation of dysregulated inorganic phosphate—phosphate toxicity—as a pathophysiological determinant of diabetes and diabetic complications. Phosphorus, an essential micronutrient, is closely linked to the cellular metabolism of glucose for energy production, and serum inorganic phosphate is often transported into cells along with glucose during insulin therapy. Mitochondrial dysfunction and apoptosis, endoplasmic reticulum stress, neuronal degeneration, and pancreatic cancer are associated with dysregulated levels of phosphate in diabetes. Ectopic calcification involving deposition of calcium-phosphate crystals is prevalent throughout diabetic complications, including vascular calcification, nephropathy, retinopathy, and bone disorders. A low-glycemic, low-phosphate dietary intervention is proposed for further investigations in the treatment and prevention of diabetes and related diabetic pathologies.

Evaluation of parathyroid function in adult male patients with transfusion dependent thalassemia

Background: In transfusion dependent thalassemic (TDT) patients regular blood transfusion leads to iron overload. This increased iron is deposited in the tissue of various system and causes organ damage. Endocrine dysfunction is very common due to iron deposition into the endocrine glands including parathyroid dysfunction. Objective: To measure plasma intact parathyroid hormone(iPTH), serum total calcium and inorganic phosphate levels in adult male patients with TDT. Methods:This cross sectional study was conducted in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University, Dhaka from March 2018 to February 2019. Total 35 TDT male patients aged 18 to 40 year and 35 age matched apparently healthy male subjects were enrolled for this study as control. The TDT patients were selected from the outpatient department of Hematology and Transfusion Medicine. For assessment of parathyroid function serum albumin, plasma iPTH, serum total calcium and inorganic phosphate levels were estimated by colorimetric method using automated analyzer. For statistical analysis, independent sample t test was done. Results: In this study, plasma iPTH and serum corrected calcium levels were significantly (p < 0.001) lower in patients with TDT than those of healthy control. Again, Serum inorganic phosphate and ALP levels were significantly (p < 0.001) higher in patients with TDT than those of healthy control. Moreover, 2.86% of TDT patients had low iPTH. Conclusion: From this study, it can be concluded that reduced parathyroid function was associated with TDT. J Bangladesh Soc Physiol. 2019, December; 14(2): 77-81

Biochemical Bone Markers for Early Detection of Osteopaenia of Prematurity

Osteopaenia of prematurity (OOP) imposes the risk of fractures and growth failure to premature infants. Studies have investigated the validity of biochemical markers of osteopaenia but till date it is not established. So, this study was intended to examine the diagnostic performance of biochemical markers in early detection of osteopaenia of prematurity. This prospective study was conducted in the Neonatal Intensive Care Unit (NICU), Department of Neonatology, Bangabandhu Sheikh Mujib Medical University during June 2013 to February 2014. A total of 100 premature infants with gestational age ? 34 weeks were consecutively included over 9 months period. Serum alkaline phosphatase, serum calcium and serum inorganic phosphates were measured from 1 week of chronological age until corrected term age. At corrected term age, radiologic examination was done for the assessment of osteopaenia. Of the enrolled infants, 36/78 (46%) developed radiological evidence of osteopaenia. Serum inorganic phosphate level was significantly less in osteopaenic infants than non-osteopaenic infants throughout first two months of life (p <0.001). The area under ROC curve for serum inorganic phosphate was 85% (p = 0.001). If the cut off value of serum inorganic phosphate was set at 3.6 mg/dl, then a sensitivity of 86% and a specificity of 49% were obtained. Low serum inorganic phosphate at 3 weeks of life can be used as a marker for early detection of osteopaenia of prematurity.