Low Phosphate Levels Research Articles

Postoperative Hypophosphatemia as a Prognostic Factor for Postoperative Pancreatic Fistula: A Systematic Review

Background and Objectives: Postoperative pancreatic fistula (POPF) is one of the most challenging complications after pancreatic resections, associated with prolonged hospital stay and high mortality. Early identification of pancreatic fistula is necessary for the treatment to be effective. Several prognostic factors have been identified, although it is unclear which one is the most crucial. Some studies show that post-pancreatectomy hypophosphatemia may be associated with the development of POPF. The aim of this systematic review was to determine whether postoperative hypophosphatemia can be used as a prognostic factor for postoperative pancreatic fistula. Materials and Methods: The systematic literature review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations (PRISMA) and was registered in the International Prospective Register of Systematic Reviews (PROSPERO). The PubMed, ScienceDirect, and Web of Science databases were systematically searched up to the 31st of January 2022 for studies analyzing postoperative hypophosphatemia as a prognostic factor for POPF. Data including study characteristics, patient characteristics, operation type, definitions of postoperative hypophosphatemia and postoperative pancreatic fistula were extracted. Results: Initially, 149 articles were retrieved. After screening and final assessment, 3 retrospective studies with 2893 patients were included in this review. An association between postoperative hypophosphatemia and POPF was found in all included studies. Patients undergoing distal pancreatectomy were more likely to develop severe hypophosphatemia compared to patients undergoing proximal pancreatectomy. Serum phosphate levels on postoperative day 4 (POD 4) and postoperative day 5 (POD 5) remained significantly lower in patients who developed leak-related complications showing a slower recovery of hypophosphatemia from postoperative day 3 (POD 3) through postoperative day 7 (POD 7). Moreover, body mass index (BMI) higher than 30 kg/m2, soft pancreatic tissue, abnormal white blood cell count on postoperative day 3 (POD 3), and shorter surgery time were associated with leak-related complications (LRC) and lower phosphate levels. Conclusions: Early postoperative hypophosphatemia might be used as a prognostic biomarker for early identification of postoperative pancreatic fistula. However, more studies are needed to better identify significant cut-off levels of postoperative hypophosphatemia and development of hypophosphatemia in the postoperative period.

Oxidative metabolism is impaired by phosphate deficiency during fracture healing and is mechanistically related to BMP induced chondrocyte differentiation

Prior studies of acute phosphate restriction during the endochondral phase of fracture healing showed delayed chondrocyte differentiation was mechanistically linked to decreased bone morphogenetic protein signaling. In the present study, transcriptomic analysis of fracture callus gene expression in three strains of mice was used to identify differentially expressed (FDR = q ≤ 0.05) genes in response to phosphate (Pi) restriction. Ontology and pathway analysis of these genes showed that independent of genetic background, a Pi-deficient diet downregulated (p = 3.16 × 10−23) genes associated with mitochondrial oxidative phosphorylation pathways as well as multiple other pathways of intermediate metabolism. Temporal clustering was used to identify co-regulation of these specific pathways. This analysis showed that specific Ox/Phos, tricarboxylic acid cycle, pyruvate dehydrogenase. Arginine, proline metabolism genes, and prolyl 4-hydroxylase were all co-regulated in response to dietary Pi restriction. The murine C3H10T½ mesenchymal stem cell line was used to assess the functional relationships between BMP2-induced chondrogenic differentiation, oxidative metabolism and extracellular matrix formation. BMP2-induced chondrogenic differentiation of C3H10T½ was carried out in culture media in the absence or presence of ascorbic acid, the necessary co-factor for proly hydroxylation, and in media with normal and 25 % phosphate levels. BMP2 treatment led to decreased proliferation, increased protein accumulation and increased collagen and aggrecan gene expression. Across all conditions, BMP2 increased total oxidative activity and ATP synthesis. Under all conditions, the presence of ascorbate further increased total protein accumulation, proly-hydroxylation and aggrecan gene expression, oxidative capacity and ATP production. Lower phosphate levels only diminished aggrecan gene expression with no other effects of metabolic activity being observed. These data suggest that dietary phosphate restriction controls endochondral growth in vivo indirectly through BMP signaling, which upregulates oxidative activity that is linked to overall protein production and collagen hydroxylation.

Application of UV-Visible Spectroscopy in Kinetic Study of Molybdate Complexation Reactions and Phosphate Content Quantitation

UV-visible spectroscopic measurements were used to characterize the formation of two ammonium-molybdate complexes, to elucidate its kinetics, and to carry out spectrophotometric quantitation of percent phosphate content in selected commercially available fertilizers. The kinetic study of ammonium-molybdate [(NH3)6Mo7O24] reaction with hydrazine (N2H2) yielding ammonium-hydrazine-molybdate complex (AHM) and that of reaction of AHM with phosphate [PO4]3- to give phospho-ammonium-hydrazine-molybdate (AHPM) complex revealed that both proceed via zero-order kinetics (R2= 0.99) with rate constants in the order of 10-5 and 10-4 M/s respectively. The kinetic experiments revealed that the rate of formation of the AHM complex is sensitive to an increase in N2H2 ligand concentration. For both reactions, the highest complexation rates were observed within the first 1000 s. Complex dissociation and association equilibria events were observed at extended reaction periods in the kinetic experiments. The AHPM system (containing complexed phosphates) used in spectrophotometric quantitation of phosphate levels in fertilizer samples was found to obey the Beer-Lambert equation in the visible region at λ max. = 820 nm within the concentration range of 5 – 90% phosphate content (R2 = 0.99). Of the fertilizer randomized sampled from Nakuru Municipality in Kenya, and analyzed the percent phosphate content among the inorganic fertilizers was found to range between 61.7% - 82% with a mean of 72.86% +/- 6.98 SD. Whereas in the organic fertilizer samples investigated, it was found to range between 43.8% - 58.2% with means of 52.55% +/- 6.77 SD. The organic fertilizers were found to have significantly lower phosphate levels based on an unpaired t-test revealing that the mean percent concentrations between the two groups of fertilizer samples tested are significantly different at 95% CI (P value < 0.05).

Impact of X-Linked Hypophosphatemia on Muscle Symptoms

X-linked hypophosphatemia (XLH) is the most common hereditary form of rickets and deficiency of renal tubular phosphate transport in humans. XLH is caused by the inactivation of mutations within the phosphate-regulating endopeptidase homolog X-linked (PHEX) gene and follows an X-dominant transmission. It has an estimated frequency of 1 case per 20,000, and over 300 distinct pathogenic variations have been reported that result in an excess of fibroblast growth factor 23 (FGF23) in the serum. Increased levels of FGF23 lead to renal phosphate loss, decreased serum 1,25-dihydroxyvitamin D, and increased metabolism of 1,25-dihydoxyvitamin D, resulting in hypophosphatemia. Major clinical manifestations include rickets, bone deformities, and growth retardation that develop during childhood, and osteomalacia-related fractures or pseudo-fractures, degenerative osteoarthritis, enthesopathy, dental anomalies, and hearing loss during adulthood, which can affect quality of life. In addition, fatigue is also a common symptom in patients with XLH, who experience decreased motion, muscle weakness, and pain, contributing to altered quality of life. The clinical and biomedical characteristics of XLH are extensively defined in bone tissue since skeletal deformations and mineralization defects are the most evident effects of high FGF23 and low serum phosphate levels. However, despite the muscular symptoms that XLH causes, very few reports are available on the effects of FGF23 and phosphate in muscle tissue. Given the close relationship between bones and skeletal muscles, studying the effects of FGF23 and phosphate on muscle could provide additional opportunities to understand the interactions between these two important compartments of the body. By describing the current literature on XLH and skeletal muscle dysfunctions, the purpose of this review is to highlight future areas of research that could contribute to a better understanding of XLH muscular disability and its management.

PSAT228 Hereditary Hypophosphatemic Rickets: Management in Adults

Abstract Introduction Hereditary Hypophosphatemic Rickets (HHR) is a group of rare inherited disorders consisting of X-linked hypophosphatemic rickets (XLHR, prevalence 1 in 20,000 births), autosomal dominant hypophosphatemic rickets (ADHR), and autosomal recessive hypophosphatemic rickets (ARHR). XLHR is caused by loss of function mutation of the PHEX gene, ARHR is caused by loss of function mutation of the DMP1/ENPP1 gene and ADHR is caused by activating point mutations in FGF23. These mutations result in renal phosphate wasting, hypophosphatemia, and impaired bone mineralization. It presents in childhood as skeletal deformities, abnormal gait, skeletal pain, dental abnormalities, and stunted growth. Adults have osteomalacia-related pain, fractures, and arthritis. The diagnosis is made by findings consistent with rickets and normal serum calcium, normal 25-hydroxy vitamin D, low-normal 1,25-dihydroxy vitamin D, elevated alkaline phosphatase activity, and low phosphate levels. Urine studies show low urine calcium and decreased tubular maximum reabsorption of phosphate, confirming renal wasting of phosphate. The goal of treatment in adults is to reduce pain, prevent fractures, enhance mobility, and decrease osteomalacia. Phosphate and vitamin D supplementations are used with close monitoring as it is associated with severe adverse events. It can cause hypercalcemia leading to nephrocalcinosis, nephrolithiasis, chronic kidney disease, and hyperparathyroidism. There is no evidence that the treatment affects long-term skeletal complications. Burosumab, a monoclonal antibody that inhibits FGF23, is approved for the treatment of XLHR. No studies are available about the use of Burosumab in ADHR or ARHR. Case Presentation A 18-year-old male with past medical history of hypophosphatemic rickets with multiple fractures, on oral phosphate tablets and calcitriol, presented to the Endocrinology clinic to establish care. He had been following Pediatric Endocrinology in the past. His blood work showed normal calcium, low phosphate of 1.6 mg/dl (normal: 2.5-4.5 mg/dl), vitamin D 25 hydroxy level of 26 ng/ml (normal: 20-100 ng/ml), vitamin D 1,25-dihydroxy level of 25 pg/ml (normal: 30-80 pg/ml), intact parathyroid hormone level of 549 pg/ml (normal: 15-65 pg/ml), and alkaline phosphatase of 438 U/l (normal: 40-150 U/l). Urine calcium was low and urine phosphorus was elevated with phosphate/creatinine ratio more than 2000 (normal: 60-962), consistent with renal phosphate wasting. Genetic testing in the past was negative for PHEX gene mutation, so he was not a candidate for Burosumab. Conclusion There is limited knowledge about Hereditary Hypophosphatemic Rickets, especially ADHR and ARHR due to limited cases (less than 100 cases reported so far). The current standard of treatment of HHR is sub-optimal and associated with adverse effects. Burosumab has not been tested in ADHR or ARHR, so it is unclear if it will be beneficial in this subgroup. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Treating 'osteoporosis': a near miss in an unusual case of FGF-23-mediated hypophosphataemic osteomalacia.

We present the case of a 60-year-old female who developed repeated atraumatic stress fractures. She was initially diagnosed with osteoporosis based on her dual-energy X-ray absorptiometry (DXA) scan bone mineral density (BMD) T-scores and started on denosumab therapy. Secondary osteoporosis screen revealed abnormal myeloma screen and low serum phosphate levels. It was thought that the patient had multiple myeloma with associated Fanconi-related tubular dysfunction. However, fibroblast growth factor-23 (FGF-23) levels were grossly elevated, making Fanconi syndrome unlikely. The patient was subsequently diagnosed with two separate conditions, namely cardiac amyloid light-chain (AL) amyloidosis and FGF-23-related hypophosphataemia, likely due to tumour-induced osteomalacia. This case highlights the importance of excluding osteomalacia as a cause of low BMD and checking FGF-23 levels in the workup for hypophosphataemia. Tumour-induced osteomalacia is a difficult diagnosis as the tumour is often small and slow growing. Imaging may fail to identify a tumour, and treatment therefore consists of calcitriol and phosphate replacement. Tumour-induced osteomalacia should be suspected in the adult presenting with new-onset hypophosphataemia, elevated FGF-23 levels and isolated renal phosphate wasting. Serum phosphate is not part of the routine chemistry panels. Routinely checking phosphate levels prior to initiating antiresorptive therapy is warranted. DXA cannot distinguish low bone mineral density due to osteoporosis from osteomalacia. Antiresorptive therapy should be avoided in osteomalacia due to the risk of clinical and radiographic deterioration.

Hypophosphatemia Is Associated With Postoperative Morbidity After Cytoreductive Surgery and Heated Intraperitoneal Chemotherapy: A Retrospective Study.

Hypophosphatemia following surgery is associated with a higher rate of postoperative complications; however, the significance of postoperative hypophosphatemia after cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) is unknown. A prospectively maintained database was queried for all patients who underwent CRS/HIPEC for any histology at the Mount Sinai Health System. The perioperative serum phosphate levels, postoperative complications, and comorbidities were compared between patients with or without major complications. From 2007 to 2018, 327 patients underwent CRS/HIPEC. Most of the patients had low phosphate levels on postoperative day (POD) 2, reaching a median nadir of 2.3mg/dL on POD 3. Patients with major complications had significantly lower levels of serum phosphate on POD 5-7 compared with patients without complications, with median serum phosphate 2.2mg/dL (IQR 1.9-2.4) versus 2.7mg/dL, (IQR 2.3-3), P<0.01. Hypophosphatemia on POD 5-7 was also more frequent in patients who developed an anastomotic leak, with median serum phosphate 2.2mg/dL (IQR 1.9-2.6) versus 2.8mg/dL (IQR 2.2-3.2), P=0.001. On multivariate analysis, the number of organs resected at surgery, diaphragm resection, postoperative intensive care unit stay, and serum phosphate level <2.4mg/dL on POD 5-7 were independently associated with a major complication after CRS/HIPEC. Following CRS/HIPEC, POD 5-7 hypophosphatemia is associated with severe postoperative complications and anastomotic leak.

Association Between Low Serum Phosphate Level and Risk of Falls in Hospitalized Patients Over 50 Years of Age: A Retrospective Observational Cohort Study.

PurposeFalls are the leading cause of injury among hospitalized patients, particularly among older patients. We investigated the association between serum phosphate (s-phosphate) levels and the risk of in-hospital falls.Patients and MethodsThis retrospective observational cohort study included all patients aged over 50 years who were admitted to Yongin Severance Hospital in South Korea between January 2018 and March 2021. Demographic, anthropometric, and biochemical parameters were recorded on admission. S-phosphate levels were classified into three groups: below normal (<2.8 mg/dL), normal (2.8–4.4 mg/dL), and above normal (≥4.5 mg/dL). The normal group was further stratified into tertiles (2.8–3.2, 3.3–3.7, and 3.8–4.4 mg/dL). The incidence of in-hospital falls was compared between the five groups. Logistic regression analyses were performed to assess the association between s-phosphate levels and the incidence of falls during the hospital stay, with clinical factors included as covariates in the multivariable models.ResultsA total of 15,485 patients (female: 52.1%) with a median age of 70.0 years (interquartile range: 60.0–79.0 years) were included in the analysis, of whom 295 (1.9%) experienced a fall during the hospital stay. The incidence of falls was significantly higher among patients with lower s-phosphate levels, and this relationship also applied among patients with s-phosphate levels within the normal range as well. The association between lower s-phosphate levels and increased risk of falls remained significant in the adjusted analyses.ConclusionA lower s-phosphate level on admission was independently associated with an increased risk of in-hospital falls. Further studies are needed to determine whether the s-phosphate level on admission could improve prediction of the risk of in-hospital falls.

Blood alcohol levels after standardized intake of alcohol are related to measured blood phosphate levels

The role of blood phosphate in alcohol metabolism has not been studied. In this explorative experimental study, the relationship between blood phosphate levels and metabolism of alcohol was investigated. Twenty young male volunteers were given alcohol relative to body weight to make them reach a theoretical blood alcohol concentration (BAC) of 0.12%. Ten measurements of BAC were taken across the time from intake, to peak and total elimination. The results indicated that individuals with high blood phosphate levels achieved a lower BAC maximum than those with low blood phosphate levels. The difference between the highest and lowest maximum BAC was as much as 30–40% and correlated negatively to physiological blood phosphate levels. The results suggest that phosphate plays a role in prehepatic, possibly gastric, alcohol metabolism. The Alcohol Dehydrogenase enzyme 7 (ADH7) is represented in the upper gastrointestinal tract and may be the enzyme responsible for this variation in the blood alcohol concentration reached.

Hypo- and Hyperphosphatemia at Admission as Independent Factors of Mortality of COVID-19 Patients: Findings from a Retrospective Cohort Study.

Electrolyte imbalances are common in COVID-19 infection and are associated with poor outcomes in hospitalized patients. This study examined whether serum phosphate imbalances at admission are associated with mortality in hospitalized COVID-19 patients. In this registry-based single-center retrospective cohort study, 1349 inpatients with COVID-19 were included from March 2020 to March 2021 in an academic hospital in Ilam (southwest Iran). The Cox proportional hazard (PH) regression model was applied to the data set of COVID-19. The in-hospital median survival time for patients with low, normal, and high serum phosphate levels was 14, 25, and 8 days, respectively. In a multivariate model, adjusted for the other variables, patients with hypophosphatemia (adjusted hazard ratio [HR], 2.53; 95% CI, 1.15 - 5.58; P = 0.02) and hyperphosphatemia (adjusted HR, 1.77; 95% CI, 1.00 - 3.14; P = 0.05) had an increased mortality hazard compared with those who had normal levels of serum phosphate. Our results demonstrate associations of hypophosphatemia and hyperphosphatemia with increased in-hospital mortality in COVID-19 patients. Intensive medical care and more attention must be paid to COVID-19 patients with serum phosphate imbalances at admission.

Genome Analysis of Enterobacter asburiae and Lelliottia spp. Proliferating in Oligotrophic Drinking Water Reservoirs and Lakes.

Surface waters are one of the main sources for drinking water production, and thus microbial contamination should be as minimal as possible. However, high concentrations of coliform bacteria were detected in reservoirs and lakes used for drinking water production during summer months due to autochthonous proliferation processes. Here, we present the genomic analyses of 17 strains of Enterobacter asburiae and Lelliottia spp. proliferating in reservoirs and lakes with special focus on the hygienic relevance, antibiotic resistance, and adaptations to the oligotrophic environments. The genomes contain neither genes for the type III secretion system nor cytotoxins or hemolysins, which are considered typical virulence factors. Examination of antibiotic resistance genes revealed mainly efflux pumps and β-lactamase class C (ampC) genes. Phenotypically, single isolates of Enterobacter asburiae showed resistance to fosfomycin and ceftazidime. The genome analyses further suggest adaptations to oligotrophic and changing environmental conditions in reservoirs and lakes, e.g., genes to cope with low nitrate and phosphate levels and the ability to utilize substances released by algae, like amino acids, chitin, alginate, rhamnose, and fucose. This leads to the hypothesis that the proliferation of the coliform bacteria could occur at the end of summer due to algae die-off. IMPORTANCE Certain strains of coliform bacteria have been shown to proliferate in the oligotrophic water of drinking water reservoirs and lakes, reaching values above 104 per 100 mL. Such high concentrations challenge drinking water treatment, and occasionally the respective coliform bacteria have been detected in the treated drinking water. Thus, the question of their hygienic relevance is of high importance for water suppliers and authorities. Our genomic analyses suggest that the strains are not hygienically relevant, as typical virulence factors are absent and antibiotic resistance genes in the genomes most likely are of natural origin. Furthermore, their presence in the water is not related to fecal contamination. The proliferation in reservoirs and lakes during stable summer stratification is an autochthonic process of certain E. asburiae and Lelliottia strains that are well adapted to the surrounding oligotrophic environment.

The slow-evolving Acorus tatarinowii genome sheds light on ancestral monocot evolution

Monocots are one of the most diverse groups of flowering plants, and tracing the evolution of their ancestral genome into modern species is essential for understanding their evolutionary success. Here, we report a high-quality assembly of the Acorus tatarinowii genome, a species that diverged early from all the other monocots. Genome-wide comparisons with a range of representative monocots characterized Acorus as a slowly evolved genome with one whole-genome duplication. Our inference of the ancestral monocot karyotypes provides new insights into the chromosomal evolutionary history assigned to modern species and reveals the probable molecular functions and processes related to the early adaptation of monocots to wetland or aquatic habitats (that is, low levels of inorganic phosphate, parallel leaf venation and ephemeral primary roots). The evolution of ancestral gene order in monocots is constrained by gene structural and functional features. The newly obtained Acorus genome offers crucial evidence for delineating the origin and diversification of monocots, including grasses.

MO938: Variability of Serum Phosphate in Incident Hemodialysis Patients: Association With All-Cause Mortality

Abstract BACKGROUND AND AIMS In maintenance hemodialysis, both low and high serum phosphate levels are related to patient outcomes. We aimed to further explore the relation between serum phosphate (P) variability and all-cause mortality. METHOD All adult incident hemodialysis patients treated in U.S. Fresenius Kidney Care clinics between January 2010 and October 2018 were included. The first 6 months on hemodialysis were defined as baseline, months 7–18 as the follow-up period. All-cause mortality was recorded during follow-up. We quantitated variability as directional range (DR), a metric that describes during baseline the difference between the largest and the smallest value; the DR is positive when the smallest value precedes the largest; otherwise, the DR is negative. Cox proportional hazards models with spline terms were applied to explore the association between DR and SD of serum P and all-cause mortality. Additionally, tensor product smoothing splines were computed to study the interactions of P with the DR and SD of P and their joint associations with outcomes. All analyses were adjusted for demographics, comorbidities and nutritional parameters. RESULTS A total of 281 356 patients were included, 258 741 patients were studied. The average age was 62.3 years, 58% were males, 68% were diabetic, 10% with COPD and 25% with CHF. Baseline mean serum P was 5.07 mg/dL, the median DR was + 1.7 mg/dL and the median SD was 0.97. Our results indicate that both higher and lower levels of DR are associated with a higher risk of mortality (Fig. 1). With higher levels of serum P, both lower (negative) and higher levels of DR of serum P were associated with a higher risk of mortality (Fig. 2). In patients with lower levels of serum P, a negative level of DR is associated with a high mortality risk, while the association is attenuated in patients with higher (positive) levels of DR (Fig. 2). On all levels of serum P, higher SD is associated with a higher risk of mortality. CONCLUSION Stable serum P levels between 4 and 6 mg/dL are associated with the best outcomes. Negative DR of serum P is associated with particularly high HR for all-cause mortality in the presence of serum P levels &amp;lt;3 mg/dL, possibly because patients are generally malnourished or inflamed, and a further reduction of serum P indicates nutritional deterioration. Serum P &amp;gt; 8 mg/dL is associated with increased all-cause mortality, irrespective of DR.

Abstract #1180511: Primary Hyperparathyroidism- Indian data

Primary hyperparathyroidism is the overproduction of parathyroid hormone (PTH) resulting in abnormal calcium in the blood with an associated low phosphate levels. It is not common with a frequency of occurrence of 66 per 100,000 person years in women and 25 per 100,000 person years in men. The mean age at diagnosis is 52 to 56 years. The most common cause is a solitary adenoma.

Alkalinity and diatom assemblages in lowland streams: How to separate alkalinity from inorganic phosphorus in ecological assessments?

Benthic algae are widely used as ecological indicators of the ecological status of streams because they are widely distributed, they show high species diversity and they respond rapidly to human pressures in particular eutrophication and organic pollution. Recent findings have highlighted that in addition to human pressures, alkalinity may also play a role for community composition as bicarbonate becomes an increasingly important carbon source for photosynthesis when alkalinity increases. With this study, we aimed to elucidate how alkalinity influences the distribution of diatoms in Danish lowland streams, and to explore ifdiatom assemblage patterns can be affected by alkalinity in a way that interferes with the ecological assessment using diatom-based indices. We found that alkalinity affect the benthic algae community in lowland streams and that different species of diatoms were associated with different levels of alkalinity, a finding that might indicate dissimilarities in the efficiency of their HCO3− use. Nitzschia intermedia, Synedra acus, Nitzschia recta, Diatoma tenue, and Nitzschia linearis were associated with high alkalinity, whereas Synedra rumpens, Fragilaria vaucheriae, Psammothidium bioretii, and Gomphonema parvulum were associated with low alkalinity in streams with very low levels of phosphate. We also found that the Danish indicator for ecological status in streams (a combination of two Austrian indices, the Saprobic Index (SID) and the Trophic Index (TID) may exceed levels acceptable for good ecological status in moderate to high alkaline streams despite low phosphate levels. These findings highlight the need for the development of a diagnostic method to disentangle the effects of alkalinity from eutrophication and, additionally, that we need more insight into the autecology of species to interpret ecological assessments to be able to guide management efforts.

Parathyroid hormone and phosphate homeostasis in patients with Bartter and Gitelman syndrome: an international cross-sectional study.

Small cohort studies have reported high parathyroid hormone (PTH) levels in patients with Bartter syndrome and lower serum phosphate levels have anecdotally been reported in patients with Gitelman syndrome. In this cross-sectional study, we assessed PTH and phosphate homeostasis in a large cohort of patients with salt-losing tubulopathies. Clinical and laboratory data of 589 patients with Bartter and Gitelman syndrome were provided by members of the European Rare Kidney Diseases Reference Network (ERKNet) and the European Society for Paediatric Nephrology (ESPN). A total of 285 patients with Bartter syndrome and 304 patients with Gitelman syndrome were included for analysis. Patients with Bartter syndrome type I and II had the highest median PTH level (7.5pmol/L) and 56% had hyperparathyroidism (PTH>7.0pmol/L).Serum calcium was slightly lower in Bartter syndrome type I and II patients with hyperparathyroidism (2.42versus 2.49mmol/L; P=.038) compared to those with normal PTH levels and correlated inversely with PTH (rs -0.253; P=.009). Serum phosphate and urinary phosphate excretion did not correlate with PTH. Overall, 22% of patients had low serum phosphate levels (phosphate-standard deviation score < -2), with the highest prevalence in patients with Bartter syndrome type III (32%). Serum phosphate correlated with tubular maximum reabsorption of phosphate/glomerular filtration rate (TmP/GFR) (rs 0.699; P <.001), suggesting renal phosphate wasting. Hyperparathyroidism is frequent in patients with Bartter syndrome type I and II. Low serum phosphate is observed in a significant number of patients with Bartter and Gitelman syndrome and appears associated with renal phosphate wasting.

Efficient fertilizer production from low phosphate water using in situ-formed vaterite/calcite calcium carbonate composite microspheres

Phosphate, as an important non-renewable agricultural resource, needs to be recovered from wastewater at mg/L scale. Calcite carbonate fine powder was used in P-recovery but could only work in recovering high concentration phosphate. Herein, a new strategy is explored using in situ-formed CaCO3 microspheres (CaCO3-in situ) to realize efficient and fast P-recovery by adding CaCl2 and Na2CO3 solution into low phosphate water (10 mg-P/L). We find that freshly in situ-formed CaCO3 nanoparticles can capture phosphate ions very efficiently and self-assemble into composite CaCO3 microspheres consisting of vaterite and calcite phases. Phosphate ions are possibly immobilized between CaCO3 nanoparticles which stimulate the formation of metastable vaterite CaCO3. Under optimized conditions (Ca/P molar ratio, 6/1), 98% of phosphate can be recovered with a rather low residual phosphate level of ~0.2 mg-P/L within only 30 min which is much time-saving than existing methods. Importantly, superior class P-fertilizer can be obtained with P2O5 content of 20.8 wt% using this novel CaCO3-in situ recovery strategy, which is 4 times as high as that using prepared calcite CaCO3 nanoparticles. The yield of pakchoi, a fast-growing vegetable, was increased by 58.9% (fresh weight) when using the prepared CaCO3-in situ-P fertilizer. This strategy provides a new way of recycling low concentration phosphate while producing high quality fertilizer.

High-Level Circulating Total Calcium and Low Phosphate as Predictors of Insulin Resistance among Non-Diabetic Taxi-Motorbike Drivers Living and Working in Cotonou, Benin

Insulin resistance (IR) is a well-recognized marker of increased cardiovascular diseases (CVDs) and type 2 diabetes (T2D) risk. Therefore, screening for IR predictors would help reduce the likelihood of progression from early stage of IR to T2D or CVDs. However, the knowledge of association between IR and circulating total calcium (CTCa) and phosphate levels among non-diabetic patients in Benin is lacking. We investigated whether CTCa and phosphate levels within the normal ranges are associated with IR risk among taxi-motorbike drivers (TMDs) living and working in Cotonou. We evaluated 134 non-diabetic TMDs (aged 22 - 59 years) based on CTCa, phosphate, glucose, fasting insulin, and IR levels. IR was assessed using the homeostatic model assessment-insulin resistance (HOMA-IR). IR was defined as the 75th percentile of HOMA-IR value. Cardiometabolic factors were analyzed by tertiles of CTCa and phosphate levels (low, middle, and high groups). Logistic regression models evaluated the relationships between IR and CTCa and phosphate levels. Our results showed that participants with high CTCa levels had the highest prevalence of IR, elevated total cholesterol and high-density lipoprotein cholesterol. In a fully adjusted model, the odd ratio (OR) of having IR comparing the highest (>2.50 mmol/L) to the lowest CTCa levels (1.23 mmol/L) and the lowest levels (<1.10 mmol/L) of phosphate was 0.28 (p = 0.037). In conclusion, our study demonstrates that elevated CTCa and low phosphate levels are significant predictors of IR in non-diabetic patients. Continuous monitoring of these markers may help identify earlier individuals at greatest IR risk.

Modifying the resin type of hybrid anion exchange nanotechnology (HAIX-Nano) to improve its regeneration and phosphate recovery efficiency

In order to avoid eutrophication of freshwater systems, regulations all around the world have become increasingly stringent toward the maximum phosphate concentration allowed in wastewater discharges. Traditional phosphate removal methods such as chemical precipitation and enhanced biological phosphorus removal struggle to lower phosphate levels to the new requirements. Hybrid anion exchange nanotechnology (HAIX-Nano) is composed of a selective adsorption material able to remove phosphate down to levels close to zero. Moreover, HAIX-Nano is not affected by intermittent flow and does not produce sludge making it an interesting alternative. The regeneration process of HAIX-Nano typically requires a chemical solution with a high concentration of sodium hydroxide (NaOH) and sodium chloride (NaCl) (2–5% w/w of each). To lower the environmental impact and the operational cost of the technology, this study aims to enhance the HAIX-Nano regeneration efficiency. Therefore, the backbone of HAIX-Nano, which is normally a strong base anionic (SBA) resin, was changed for a weak base anionic (WBA) resin. The resulting material (WBA-2) exhibited a higher adsorption capacity than the traditional version of HAIX-Nano (SBA-1) under the tested conditions, while also showing a much higher regeneration efficiency. For a desorption solution of only 0.4% NaOH and no NaCl, WBA-2 showed an average regeneration efficiency of 78 ± 1% compared to SBA-1 with 24 ± 1%.

Dietary calcium phosphate strongly impacts gut microbiome changes elicited by inulin and galacto-oligosaccharides consumption

BackgroundFructo-oligosaccharides (FOS), inulin, and galacto-oligosaccharides (GOS) are widely recognized prebiotics that profoundly affect the intestinal microbiota, including stimulation of bifidobacteria and lactobacilli, and are reported to elicit several health benefits. The combination of dietary FOS and inulin with calcium phosphate was reported to stimulate commensal Lactobacillus populations and protect the host against pathogenic Enterobacteriaceae, but little is known about the effects of GOS in diets with a different level of calcium phosphate.MethodsWe investigated the microbiome changes elicited by dietary supplementation with GOS or inulin using diets with high (100 mmol/kg) and low (30 mmol/kg) calcium phosphate levels in adult Wistar rats. Rats were acclimatized to the respective experimental diets for 14 days, after which fecal material was collected, DNA was extracted from fecal material, and the V3‑V4 region of the bacterial 16S rRNA gene was amplified with PCR, followed by microbial composition analysis. In tandem, the organic acid profiles of the fecal material were analyzed.ResultsFeeding rats non-supplemented (no prebiotic-added) diets revealed that diets rich in calcium phosphate favored members of the Firmicutes and increased fecal lactic, succinic, acetic, propionic, and butyric acid levels. In contrast, relatively low dietary calcium phosphate levels promoted the abundance of mucin degrading genera like Akkermansia and Bacteroides, and resulted in increased fecal propionic acid levels and modest increases in lactic and butyric acid levels. Irrespective of the calcium phosphate levels, supplementation with GOS or inulin strongly stimulated Bifidobacterium, while only high calcium phosphate diets increased the endogenous Faecalibaculum populations.ConclusionsDespite the prebiotic’s substantial difference in chemical structure, sugar composition, oligomer size, and the microbial degradation pathway involved in their utilization, inulin and GOS modulated the gut microbiota very similarly, in a manner that strongly depended on the dietary calcium phosphate level. Therefore, our study implies that the collection of detailed diet information including micronutrient balance is necessary to correctly assess diet-driven microbiota analysis.8vuNLHgRQosTp1CET2ayTDVideo