A novel mouse model for familial hypocalciuric hypercalcemia (FHH1) reveals PTH-dependent and independent CaSR defects.

The Calcium-sensing receptor (CaSR) senses extracellular calcium, regulates parathyroid hormone (PTH) secretion, and has additional functions in various organs related to systemic and local calcium and mineral homeostasis. Familial hypocalciuric hypercalcemia type I (FHH1) is caused by heterozygous loss-of-function mutations in the CaSR gene, and is characterized by the combination of hypercalcemia, hypocalciuria, normal to elevated PTH, and facultatively hypermagnesemia and mild bone mineralization defects. To date, only heterozygous Casr null mice have been available as model for FHH1. Here we present a novel mouse FHH1 model identified in a large ENU-screen that carries an c.2579 T > A (p.Ile859Asn) variant in the Casr gene (CasrBCH002 mice). In order to dissect direct effects of the genetic variant from PTH-dependent effects, we crossed CasrBCH002 mice with PTH deficient mice. Heterozygous CasrBCH002 mice were fertile, had normal growth and body weight, were hypercalcemic and hypermagnesemic with inappropriately normal PTH levels and urinary calcium excretion replicating some features of FHH1. Hypercalcemia and hypermagnesemia were independent from PTH and correlated with higher expression of claudin 16 and 19 in kidneys. Likewise, reduced expression of the renal TRPM6 channel in CasrBCH002 mice was not dependent on PTH. In bone, mutations in Casr rescued the bone phenotype observed in Pth null mice by increasing osteoclast numbers and improving the columnar pattern of chondrocytes in the growth zone. In summary, CasrBCH002 mice represent a new model to study FHH1 and our results indicate that only a part of the phenotype is driven by PTH.

Predicting liver-related events in NAFLD: A predictive model.

BACKGROUND AND AIMS: Management of NAFLD involves noninvasive prediction of fibrosis, which is a surrogate for patient outcomes. We aimed to develop and validate a model predictive of liver-related events (LREs) of decompensation and/or HCC and compare its accuracy with fibrosis models. APPROACH AND RESULTS: Patients with NAFLD from Australia and Spain who were followed for up to 28 years formed derivation (n = 584) and validation (n = 477) cohorts. Competing risk regression and information criteria were used for model development. Accuracy was compared with fibrosis models using time-dependent AUC analysis. During follow-up, LREs occurred in 52 (9%) and 11 (2.3%) patients in derivation and validation cohorts, respectively. Age, type 2 diabetes, albumin, bilirubin, platelet count, and international normalized ratio were independent predictors of LRE and were combined into a model [NAFLD outcomes score (NOS)]. The NOS model calibrated well [calibration slope, 0.99 (derivation), 0.98 (validation)] with excellent overall performance [integrated Brier score, 0.07 (derivation) and 0.01 (validation)]. A cutoff ≥1.3 identified subjects at a higher risk of LRE, (sub-HR 24.6, p < 0.001, 5-year cumulative incidence 38% vs 1.0%, respectively). The predictive accuracy at 5 and 10 years was excellent in both derivation (time-dependent AUC,0.92 and 0.90, respectively) and validation cohorts (time-dependent AUC,0.80 and 0.82, respectively). The NOS was more accurate than the fibrosis-4 or NAFLD fibrosis score for predicting LREs at 5 and 10 years ( p < 0.001). CONCLUSIONS: The NOS model consists of readily available measures and has greater accuracy in predicting outcomes in patients with NAFLD than existing fibrosis models.

FIB-4 score as predictor of COVID-19-related severity in hospitalized patients.

AIM: To determine the impact of liver fibrosis on the prognosis of COVID and the liver injury associated with the infection. METHODS: Retrospective multicenter study including 575 patients requiring admission for COVID-19 between January and June 2020. FIB-4 was calculated within 6 months prior to infection and at 6 months post-infection. RESULTS: Baseline FIB-4 was increased in patients who died (1.91±0.95 vs. 1.43±0.85; p<0.001). In addition, the 17.1% (32/187) of patients with baseline FIB-4<1.45 died versus 52.9% (9/17) if FIB-4>3.25 (p<0.001). In the adjusted multivariate analysis, baseline FIB-4 (OR 1.61 (95%CI 1.19-2.18); p=0.002) was independently associated with mortality. Parameters associated with liver injury, including AST (28±10 vs. 45±56IU/L; p<0.001) and ALT (20±12 vs. 38±48IU/L; p<0.001) were significantly higher at admission compared to baseline. Also, FIB-4 was increased from baseline to the time of admission (1.53±0.88 vs. 2.55±1.91; p<0.001), and up to 6.9% (10/145) of patients with FIB-4<1.45 at admission died versus 47.5% if FIB-4>3.25 (58/122) (p<0.001). In the adjusted multivariate analysis, FIB-4 at admission (OR 1.14 (95%CI 1.03-1.27); p=0.015) was independently associated with mortality. Also, AST (42±38 vs. 22±17IU/L; p<0.001) and ALT (40±50 vs. 20±19 IU/L; p<0.001) were significantly reduced at 6 months after the resolution of infection. Accordingly, FIB-4 decreased significantly (2.12±1.25 vs. 1.32±0.57; p<0.001) six months after the infection. CONCLUSION: Increased FIB-4, either at baseline or at the time of admission, was related to the severity and mortality related to SARS-CoV-2 infection. However, the liver damage expressed by elevated transaminases and FIB-4 was reversible in most of patients.

Metabolic subtypes of patients with NAFLD exhibit distinctive cardiovascular risk profiles.

BACKGROUND AND AIMS: We previously identified subsets of patients with NAFLD with different metabolic phenotypes. Here we align metabolomic signatures with cardiovascular disease (CVD) and genetic risk factors. APPROACH AND RESULTS: We analyzed serum metabolome from 1154 individuals with biopsy-proven NAFLD, and from four mouse models of NAFLD with impaired VLDL-triglyceride (TG) secretion, and one with normal VLDL-TG secretion. We identified three metabolic subtypes: A (47%), B (27%), and C (26%). Subtype A phenocopied the metabolome of mice with impaired VLDL-TG secretion; subtype C phenocopied the metabolome of mice with normal VLDL-TG; and subtype B showed an intermediate signature. The percent of patients with NASH and fibrosis was comparable among subtypes, although subtypes B and C exhibited higher liver enzymes. Serum VLDL-TG levels and secretion rate were lower among subtype A compared with subtypes B and C. Subtype A VLDL-TG and VLDL-apolipoprotein B concentrations were independent of steatosis, whereas subtypes B and C showed an association with these parameters. Serum TG, cholesterol, VLDL, small dense LDL5,6 , and remnant lipoprotein cholesterol were lower among subtype A compared with subtypes B and C. The 10-year high risk of CVD, measured with the Framingham risk score, and the frequency of patatin-like phospholipase domain-containing protein 3 NAFLD risk allele were lower in subtype A. CONCLUSIONS: Metabolomic signatures identify three NAFLD subgroups, independent of histological disease severity. These signatures align with known CVD and genetic risk factors, with subtype A exhibiting a lower CVD risk profile. This may account for the variation in hepatic versus cardiovascular outcomes, offering clinically relevant risk stratification.

ABIDE: An Accurate Predictive Model of Liver Decompensation in Patients With Nonalcoholic Fatty Liver-Related Cirrhosis.

BACKGROUND AND AIMS: Nonalcoholic fatty liver disease (NAFLD) is an increasingly important cause of liver cirrhosis and subsequent complications. We retrospectively developed and validated a model to predict hepatic decompensation in patients with NAFLD and cirrhosis and compared this with currently available models. APPROACH AND RESULTS: Baseline variables from an international cohort of 299 patients with biopsy-proven NAFLD with compensated cirrhosis were examined to construct a model using competing risk multivariate regression and Akaike/Bayesian information criteria. Validation was performed in 244 patients with biopsy-proven NAFLD cirrhosis from the United States. Prognostic accuracy was compared with the NAFLD fibrosis score (NFS), fibrosis-4 (FIB-4), Model for End-Stage Liver Disease (MELD), Child-Turcotte-Pugh (CTP), and albumin-bilirubin (ALBI)-FIB-4 score using time-dependent area under the curve (tAUC) analysis. During a median follow-up of 5.6 years (range 2.4-14.1) and 5.4 years (range 1.5-13.8), hepatic decompensation occurred in 81 and 132 patients in the derivation and validation cohorts, respectively. In the derivation cohort, independent predictors of hepatic decompensation (Aspartate aminotransferase/alanine aminotransferase ratio, Bilirubin, International normalized ratio, type 2 Diabetes, and Esophageal varices) were combined into the ABIDE model. Patients with a score ≥4.1 compared with those with a score <4.1 had a higher risk of decompensation (subhazard ratio, 6.7; 95% confidence interval [CI], 4.0-11.2; P < 0.001), a greater 5-year cumulative incidence (37% vs. 6%, P < 0.001), and shorter mean duration to decompensation (3.8 vs 6.7 years, P < 0.001). The accuracy of the ABIDE model at 5 years was good in the derivation (tAUC, 0.80; 95% CI, 0.73-0.84) and validation cohorts (0.78; 95% CI, 0.74-0.81) and was significantly more accurate than the NFS (0.72), FIB-4 (0.74), MELD (0.69), CTP (0.72), and ALBI-FIB-4 (0.73) (all P < 0.001). CONCLUSIONS: In patients with NAFLD and compensated cirrhosis, ABIDE, a predictive model of routine clinical measures, predicts future hepatic decompensation.

Systemic Jak1 activation causes extrarenal calcitriol production and skeletal alterations provoking stunted growth.

Mineral homeostasis is regulated by a complex network involving endocrine actions by calcitriol, parathyroid hormone (PTH), and FGF23 on several organs including kidney, intestine, and bone. Alterations of mineral homeostasis are found in chronic kidney disease and other systemic disorders. The interplay between the immune system and the skeletal system is not fully understood, but cytokines play a major role in modulating calcitriol production and function. One of the main cellular signaling pathways mediating cytokine function is the Janus kinase (JAK)--signal transducer and activator of transcription (STAT) pathway. Here, we used a mouse model (Jak1S645P+/- ) that resembles a constitutive activating mutation of the Jak1/Stat3 signaling pathway in humans, and shows altered mineral metabolism, with higher fibroblast growth factor 23 (FGF23) levels, lower PTH levels, and higher calcitriol levels. The higher calcitriol levels are probably due to extrarenal calcitriol production. Furthermore, systemic Jak1/Stat3 activation led to growth impairment and skeletal alterations. The growth plate in long bones showed decreased chondrocyte proliferation rates and reduced height of terminal chondrocytes. Furthermore, we demonstrate that Jak1 is also involved in bone remodeling early in life. Jak1S645P+/- animals have decreased bone and cortical volume, imbalanced bone remodeling, reduced MAP kinase signaling, and local inflammation. In conclusion, Jak1 plays a major role in bone health probably both, directly and systemically by regulating mineral homeostasis. Understanding the role of this signaling pathway will contribute to a better knowledge in bone growth and in mineral physiology, and to the development of selective Jak inhibitors as osteoprotective agents.

Cellular and Molecular Alterations Underlying Abnormal Bone Growth in X-Linked Hypophosphatemia.

X-linked hypophosphatemia (XLH), the most common form of hereditary hypophosphatemic rickets, is caused by inactivating mutations of the phosphate-regulating endopeptidase gene (PHEX). XLH is mainly characterized by short stature, bone deformities and rickets, while in hypophosphatemia, normal or low vitamin D levels and low renal phosphate reabsorption are the principal biochemical aspects. The cause of growth impairment in patients with XLH is not completely understood yet, thus making the study of the growth plate (GP) alterations necessary. New treatment strategies targeting FGF23 have shown promising results in normalizing the growth velocity and improving the skeletal effects of XLH patients. However, further studies are necessary to evaluate how this treatment affects the GP as well as its long-term effects and the impact on adult height.

Type 2 Diabetes and Metformin Use Associate With Outcomes of Patients With Nonalcoholic Steatohepatitis-Related, Child-Pugh A Cirrhosis.

BACKGROUND & AIMS: Factors that affect outcomes of patients with nonalcoholic steatohepatitis (NASH)-related cirrhosis are unclear. We studied associations of type 2 diabetes, levels of hemoglobin A1c (HbA1c), and use of antidiabetic medications with survival and liver-related events in patients with NASH and compensated cirrhosis. METHODS: We collected data from 299 patients with biopsy-proven NASH with Child-Pugh A cirrhosis from tertiary hospitals in Spain, Australia, Hong Kong, and Cuba, from April 1995 through December 2016. We obtained information on the presence of type 2 diabetes, level of HbA1c, and use of antidiabetic medications. Cox proportional and competing risk models were used to estimate and compare rates of transplant-free survival, hepatic decompensation, and hepatocellular carcinoma (HCC). RESULTS: A total of 212 patients had type 2 diabetes at baseline and 8 of 87 patients developed diabetes during a median follow-up time of 5.1 years (range, 0.5-10.0 y). A lower proportion of patients with diabetes survived the entire follow-up period (38%) than of patients with no diabetes (81%) (adjusted hazard ratio [aHR], 4.23; 95% CI, 1.93-9.29). Higher proportions of patients with diabetes also had hepatic decompensation (51% vs 26% of patients with no diabetes; aHR, 2.03; 95% CI, 1.005-4.11) and HCC (25% vs 7% of patients with no diabetes; aHR, 5.42; 95% CI, 1.74-16.80). Averaged annual HbA1c levels over time were not associated with outcomes. Metformin use over time was associated with a significant reduction in risk of death or liver transplantation (aHR, 0.41; 95% CI, 0.26-0.45), hepatic decompensation (aHR, 0.80; 95% CI, 0.74-0.97), and HCC (aHR, 0.78; 95% CI, 0.69-0.96). Metformin significantly reduced the risk of hepatic decompensation and HCC only in subjects with HbA1c levels greater than 7.0% (aHR, 0.97; 95% CI, 0.95-0.99 and aHR, 0.67; 95% CI, 0.43-0.94, respectively). CONCLUSIONS: In an international cohort of patients with biopsy-proven NASH and Child-Pugh A cirrhosis, type 2 diabetes increased the risk of death and liver-related outcomes, including HCC. Patients who took metformin had higher rates of survival and lower rates of decompensation and HCC.

The Formation of the Epiphyseal Bone Plate Occurs via Combined Endochondral and Intramembranous-Like Ossification.

The formation of the epiphyseal bone plate, the flat bony structure that provides strength and firmness to the growth plate cartilage, was studied in the present study by using light, confocal, and scanning electron microscopy. Results obtained evidenced that this bone tissue is generated by the replacement of the lower portion of the epiphyseal cartilage. However, this process differs considerably from the usual bone tissue formation through endochondral ossification. Osteoblasts deposit bone matrix on remnants of mineralized cartilage matrix that serve as a scaffold, but also on non-mineralized cartilage surfaces and as well as within the perivascular space. These processes occur simultaneously at sites located close to each other, so that, a core of the sheet of bone is established very quickly. Subsequently, thickening and reshaping occurs by appositional growth to generate a dense parallel-fibered bone structurally intermediate between woven and lamellar bone. All these processes occur in close relationship with a cartilage but most of the bone tissue is generated in a manner that may be considered as intramembranous-like. Overall, the findings here reported provide for the first time an accurate description of the tissues and events involved in the formation of the epiphyseal bone plate and gives insight into the complex cellular events underlying bone formation at different sites on the skeleton.

MAPK inhibition and growth hormone: a promising therapy in XLH.

X-linked hypophosphatemia (XLH) leads to growth retardation and bone deformities, which are not fully avoided by conventional treatment with phosphate and vitamin D analogs. Pediatric patients have been treated with growth hormone (GH), and recent findings suggest that blocking fibroblast growth factor 23 actions may be the most effective therapy, but its effects on growth are not known. We here report the effect of MAPK inhibition alone or associated with GH on growth and growth plate and bone structure of young Hyp (the XLH animal model) mice. Untreated Hyp mice were severely growth retarded and had marked alterations in both growth plate structure and dynamics as well as defective bone mineralization. GH accelerated growth and improved mineralization and the cortical bone, but it failed in normalizing growth plate and trabecular bone structures. MAPK inhibition improved growth and rickets and, notably, almost normalized the growth plate organization. The administration of a MAPK pathway inhibitor plus GH was the most beneficial treatment because of the positive synergistic effect on growth plate and bone structures. Thus, the growth-promoting effect of GH is likely linked to increased risk of bone deformities, whereas the association of GH and MAPK inhibition emerges as a promising new therapy for children with XLH.-Fuente, R., Gil-Peña, H., Claramunt-Taberner, D., Hernández-Frías, O., Fernández-Iglesias, Á., Alonso-Durán, L., Rodríguez-Rubio, E., Hermida-Prado, F., Anes-González, G., Rubio-Aliaga, I., Wagner, C., Santos, F. MAPK inhibition and growth hormone: a promising therapy in XLH.

Innovative Three-Dimensional Microscopic Analysis of Uremic Growth Plate Discloses Alterations in the Process of Chondrocyte Hypertrophy: Effects of Growth Hormone Treatment.

Chronic kidney disease (CKD) alters the morphology and function of the growth plate (GP) of long bones by disturbing chondrocyte maturation. GP chondrocytes were analyzed in growth-retarded young rats with CKD induced by adenine intake (AD), control rats fed ad libitum (C) or pair-fed with the AD group (PF), and CKD rats treated with growth hormone (ADGH). In order to study the alterations in the process of GP maturation, we applied a procedure recently described by our group to obtain high-quality three-dimensional images of whole chondrocytes that can be used to analyze quantitative parameters like cytoplasm density, cell volume, and shape. The final chondrocyte volume was found to be decreased in AD rats, but GH treatment was able to normalize it. The pattern of variation in the cell cytoplasm density suggests that uremia could be causing a delay to the beginning of the chondrocyte hypertrophy process. Growth hormone treatment appears to be able to compensate for this disturbance by triggering an early chondrocyte enlargement that may be mediated by Nkcc1 action, an important membrane cotransporter in the GP chondrocyte enlargement.

Fibrosis Severity as a Determinant of Cause-Specific Mortality in Patients With Advanced Nonalcoholic Fatty Liver Disease: A Multi-National Cohort Study.

BACKGROUND & AIMS: Little is known about the natural course of nonalcoholic fatty liver disease (NAFLD) with advanced fibrosis. We describe long-term outcomes and evaluate the effects of clinical and histologic parameters on disease progression in patients with advanced NAFLD. METHODS: We conducted a multi-national study of 458 patients with biopsy-confirmed NAFLD with bridging fibrosis (F3, n = 159) or compensated cirrhosis (222 patients with Child-Turcotte-Pugh scores of A5 and 77 patients with scores of A6), evaluated from April 1995 through November 2013 and followed until December 2016, death, or liver transplantation at hepatology centers in Spain, Australia, Hong Kong, and Cuba. Biopsies were re-evaluated and scored; demographic, clinical, laboratory, and pathology data for each patient were collected from the time of liver biopsy collection. Cox proportional and competing risk models were used to estimate rates of transplantation-free survival and major clinical events and to identify factors associated with outcomes. RESULTS: During a mean follow-up time of 5.5 years (range, 2.7-8.2 years), 37 patients died, 37 received liver transplants, 88 had initial hepatic decompensation events, 41 developed hepatocellular carcinoma, 14 had vascular events, and 30 developed nonhepatic cancers. A higher proportion of patients with F3 fibrosis survived transplantation-free for 10 years (94%; 95% confidence interval [CI], 86%-99%) than of patients with cirrhosis and Child-Turcotte-Pugh A5 (74%; 95% CI, 61%-89%) or Child-Turcotte-Pugh A6 (17%; 95% CI, 6%-29%). Patients with cirrhosis were more likely than patients with F3 fibrosis to have hepatic decompensation (44%; 95% CI, 32%-60% vs 6%, 95% CI, 2%-13%) or hepatocellular carcinoma (17%; 95% CI, 8%-31% vs 2.3%, 95% CI, 1%-12%). The cumulative incidence of vascular events was higher in patients with F3 fibrosis (7%; 95% CI, 3%-18%) than cirrhosis (2%; 95% CI, 0%-6%). The cumulative incidence of nonhepatic malignancies was higher in patients with F3 fibrosis (14%; 95% CI, 7%-23%) than cirrhosis (6%; 95% CI, 2%-15%). Death or transplantation, decompensation, and hepatocellular carcinoma were independently associated with baseline cirrhosis and mild (<33%) steatosis, whereas moderate alcohol consumption was associated with these outcomes only in patients with cirrhosis. CONCLUSIONS: Patients with NAFLD cirrhosis have predominantly liver-related events, whereas those with bridging fibrosis have predominantly nonhepatic cancers and vascular events.

Acute calculous cholecystitis: a real-life management study in a tertiary teaching hospital.

AIM: to describe the management of acute calculous cholecystitis in a tertiary teaching hospital and the outcomes obtained. MATERIAL AND METHODS: a retrospective single tertiary center cohort study. RESULTS: medical records of 487 patients were analyzed. The mean follow-up was 44.5 ± 17.0 months. Treatment alternatives were cholecystectomy (64.3%), conservative treatment (23.0%), endoscopic retrograde cholangiopancreatography (17.4%), percutaneous cholecystostomy (10.7%) and endoscopic ultrasound-guided gallbladder drainage (0.8%). Most cholecystectomies were delayed (88.8%). Recurrences occurred in 38.2% of patients. Although cholecystectomy was the therapeutic approach with the lowest recurrence rate once performed, 44.6% of patients that underwent delayed surgery had pre-surgical recurrences. CONCLUSIONS: delayed cholecystectomy is still commonly performed, even though it is related with a high frequency of preoperative recurrences.

Analytical, anthropometric and dietary factors associated with the development of fibrosis in patients with nonalcoholic fatty liver disease.

BACKGROUND: a prolonged non-alcoholic steatohepatitis (NASH) condition can lead to advanced stages of liver disease and the development of hepatocellular carcinoma. AIM: to evaluate analytical, anthropometric and dietary factors associated with the presence of fibrosis as this is the factor that most influences survival and evolution. METHODS: seventy-six patients with liver biopsy-diagnosed non-alcoholic fatty liver disease (NAFLD) were included. Biopsies were scored considering the NASH criteria of Kleiner. Analytical, anthropometric and dietary (survey) parameters were obtained. NAFLD-FS is a non-invasive fibrosis index and was assessed for each patient. Leptin, adiponectin, resistin and TNF-alpha serum levels were determined. RESULTS: fifty-six patients were male (73.7%) and the mean age was 44.5 ± 11.3 years of age (19-68). Thirty-nine (51.3%) (F1-F2: 84.6%; F3-4: 15.4%) patients had fibrosis in the liver biopsy. Seventeen females (85%) had fibrosis versus 22 males (39%), which was statistically significant by univariate analysis (p < 0.01). Patients with advanced fibrosis were older, with lower platelet counts, lower serum albumin, greater homeostatic model assessment insulin resistance (HOMA-IR), lower dietary lipids percentage, higher serum leptin levels and higher NAFLD Fibrosis Score (NAFLD-FS) values. This index had a negative predictive value of 98% and a positive predictive value of 60% for the detection of fibrosis. Variables independently associated with fibrosis (logistic regression) included male gender (protective factor) (0.09, 95% CI 0.01-0.7; p < 0.05) and HOMA-IR (1.7, 95% CI, 1.03-2.79; p < 0.05). CONCLUSIONS: gender and HOMA-IR were the only independent factors associated with fibrosis. NAFLD-FS could be considered as an accurate scoring system to rule out advanced fibrosis.

Effects of growth hormone treatment on growth plate, bone, and mineral metabolism of young rats with uremia induced by adenine.

BackgroundIn a model of growth retardation secondary to chronic kidney disease (CKD) induced by adenine, this study explores the effects of growth hormone (GH) therapy on growth plate and mineral metabolism.MethodsWeaning female rats receiving a 0.5% adenine diet during 21 days, untreated (AD) or treated with GH (ADGH) for 1 week, were compared with control rats receiving normal diet, either ad libitum or pair-fed with AD animals. AD and ADGH rats had similarly elevated serum concentrations of urea nitrogen, parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23).ResultsUremia induced by adenine caused growth retardation and disturbed growth cartilage chondrocyte hypertrophy. We demonstrated marked expression of aquaporin 1 in the growth plate, but its immunohistochemical signal and the expression levels of other proteins potentially related with chondrocyte enlargement, such as Na-K-2Cl cotransporter, insulin-like growth factor 1 (IGF-1), and IGF-1 receptor, were not different among the four groups of rats. The distribution pattern of vascular endothelial growth factor was also similar. AD rats developed femur bone structure abnormalities analyzed by micro-computerized tomography.ConclusionGH treatment accelerated longitudinal growth velocity, stimulated the proliferation and enlargement of chondrocytes, and did not modify the elevated serum PTH or FGF23 concentrations or the abnormal bone structure.

Effects of growth hormone treatment on growth plate, bone, and mineral metabolism of young rats with uremia induced by adenine.

This corrects the article DOI: 10.1038/pr.2017.95.

Impact of the endoscopist's experience on the negative predictive value of capsule endoscopy. / Influencia de la experiencia acumulada del explorador en el valor predictivo negativo de la cápsula endoscópica.

INTRODUCTION: The impact of the accumulated experience of the capsule endoscopy (CE) reader on the accuracy of this test is discussed. AIM: To determine whether the negative predictive value of CE findings changes along the learning curve. METHODS: We reviewed the first 900 CE read by 3 gastroenterologists experienced in endoscopy over 8 years. These 900 CE were divided into 3 groups (300 CE each): group 1 consisted of the sum of the first 100 CE read by each of the 3 endoscopists; group 2, the sum of the second 100 and groups 3, the sum of the third 100. Patients with normal CE were monitored for at least 28 months to estimate the negative predictive value. RESULTS: A total of 54 (18%) CE in group 1, 58 (19.3%) in group 2 and 47 (15.6%) in group 3 were normal, although only 34 patients in group 1, 38 in group 2 and 36 in group 3 with normal CE completed follow up and were eventually studied. The negative predictive value was 88.2% in group 1, 89.5% in group 2 and 97% in group 3 (P>.05). CONCLUSION: The negative predictive value tended to increase, but remained high and did not change significantly after the first 100 when readers are experienced in conventional endoscopy and have preliminary specific training.

Chronic kidney disease induced by adenine: a suitable model of growth retardation in uremia.

Growth retardation is a major manifestation of chronic kidney disease (CKD) in pediatric patients. The involvement of the various pathogenic factors is difficult to evaluate in clinical studies. Here, we present an experimental model of adenine-induced CKD for the study of growth failure. Three groups (n = 10) of weaning female rats were studied: normal diet (control), 0.5% adenine diet (AD), and normal diet pair fed with AD (PF). After 21 days, serum urea nitrogen, creatinine, parathyroid hormone (PTH), weight and length gains, femur osseous front advance as an index of longitudinal growth rate, growth plate histomorphometry, chondrocyte proliferative activity, bone structure, aorta calcifications, and kidney histology were analyzed. Results are means ± SE. AD rats developed renal failure (serum urea nitrogen: 70 ± 6 mg/dl and creatinine: 0.6 ± 0.1 mg/dl) and secondary hyperparathyroidism (PTH: 480 ± 31 pg/ml). Growth retardation of AD rats was demonstrated by lower weight (AD rats: 63.3 ± 4.8 g, control rats: 112.6 ± 4.7 g, and PF rats: 60.0 ± 3.8 g) and length (AD rats: 7.2 ± 0.2 cm, control rats: 11.1 ± 0.3 cm, and PF rats: 8.1 ± 0.3 cm) gains as well as lower osseous front advances (AD rats: 141 ± 13 µm/day, control rats: 293 ± 16 µm/day, and PF rats: 251 ± 10 µm/day). The processes of chondrocyte maturation and proliferation were impaired in AD rats, as shown by lower growth plate terminal chondrocyte height (21.7 ± 2.3 vs. 26.2 ± 1.9 and 23.9 ± 1.3 µm in control and PF rats) and proliferative activity index (AD rats: 30 ± 2%, control rats: 38 ± 2%, and PF rats: 42 ± 3%). The bone primary spongiosa structure of AD rats was markedly disorganized. In conclusion, adenine-induced CKD in young rats is associated with growth retardation and disturbed endochondral ossification. This animal protocol may be a useful new experimental model to study growth in CKD.

Hypophosphatemia and growth.

Over the last decade the discovery of fibroblast growth factor 23 (FGF23) and the progressive and ongoing clarification of its role in phosphate and mineral metabolism have led to expansion of the diagnostic spectrum of primary hypophosphatemic syndromes. This article focuses on the impairment of growth in these syndromes. Growth retardation is a common, but not constant, feature and it presents with large variability. As a result of the very low prevalence of other forms of primary hypophosphatemic syndromes, the description of longitudinal growth and the pathogenesis of its impairment have been mostly studied in X-linked hypophosphatemia (XLH) patients and in Hyp mice, the animal model of this disease. In general, children with XLH have short stature with greater shortness of lower limbs than trunk. Treatment with phosphate supplements and 1α vitamin D derivatives heals active lesions of rickets, but does not normalize growth of XLH patients. Patients might benefit from recombinant human growth hormone (rhGH) therapy, which may accelerate the growth rate without increasing body disproportion or correcting hypophosphatemia. These clinical data as well as research findings obtained in Hyp mice suggest that the pathogenesis of defective growth in XLH and other hypophosphatemic syndromes is not entirely dependent on the mineralization disorder and point to other effects of hypophosphatemia itself or FGF23 on the metabolism of bone and growth plate.

Blocking FGF23 signaling improves the growth plate of mice with X-linked hypophosphatemia.

Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone. X-linked hypophosphatemia (XLH) is the most prevalent inherited phosphate wasting disorder due to mutations in the PHEX gene, which cause elevated circulating FGF23 levels. Clinically, it is characterized by growth impairment and defective mineralization of bones and teeth. Treatment of XLH is challenging. Since 2018, neutralizing antibodies against FGF23 have dramatically improved the therapy of XLH patients, although not all patients fully respond to the treatment, and it is very costly. C-terminal fragments of FGF23 have recently emerged as blockers of intact FGF23 signaling. Here, we analyzed the effect on growth and bone of a short 26 residues long C-terminal FGF23 (cFGF23) fragment and two N-acetylated and C-amidated cFGF23 peptides using young XLH mice (Phex C733RMhda mice). Although no major changes in blood parameters were observed after 7 days of treatment with these peptides, bone length and growth plate structure improved. The modified peptides accelerated the growth rate probably by improving growth plate structure and dynamics. The processes of chondrocyte proliferation, death, hypertrophy, and the cartilaginous composition in the growth plate were partially improved in young treated XLH mice. In conclusion, these findings contribute to understand the role of FGF23 signaling in growth plate metabolism and show that this may occur despite continuous hypophosphatemia.