Differential DNA methylation in iPSC-derived dopaminergic neurons: a step forward on the role of SNORD116 microdeletion in the pathophysiology of addictive behavior in Prader-Willi syndrome.

INTRODUCTION: A microdeletion including the SNORD116 gene (SNORD116 MD) has been shown to drive the Prader-Willi syndrome (PWS) features. PWS is a neurodevelopmental disorder clinically characterized by endocrine impairment, intellectual disability and psychiatric symptoms such as a lack of emotional regulation, impulsivity, and intense temper tantrums with outbursts. In addition, this syndrome is associated with a nutritional trajectory characterized by addiction-like behavior around food in adulthood. PWS is related to the genetic loss of expression of a minimal region that plays a potential role in epigenetic regulation. Nevertheless, the role of the SNORD116 MD in DNA methylation, as well as the impact of the oxytocin (OXT) on it, have never been investigated in human neurons. METHODS: We studied the methylation marks in induced pluripotent stem-derived dopaminergic neurons carrying a SNORD116 MD in comparison with those from an age-matched adult healthy control. We also performed identical neuron differentiation in the presence of OXT. We performed a genome-wide DNA methylation analysis from the iPSC-derived dopaminergic neurons by reduced-representation bisulfite sequencing. In addition, we performed RNA sequencing analysis in these iPSC-derived dopaminergic neurons differentiated with or without OXT. RESULTS: The analysis revealed that 153,826 cytosines were differentially methylated between SNORD116 MD neurons and control neurons. Among the differentially methylated genes, we determined a list of genes also differentially expressed. Enrichment analysis of this list encompassed the dopaminergic system with COMT and SLC6A3. COMT displayed hypermethylation and under-expression in SNORD116 MD, and SLC6A3 displayed hypomethylation and over-expression in SNORD116 MD. RT-qPCR confirmed significant over-expression of SLC6A3 in SNORD116 MD neurons. Moreover, the expression of this gene was significantly decreased in the case of OXT adjunction during the differentiation. CONCLUSION: SNORD116 MD dopaminergic neurons displayed differential methylation and expression in the COMT and SLC6A3 genes, which are related to dopaminergic clearance.

Sunlight exposure exerts immunomodulatory effects to reduce multiple sclerosis severity.

Multiple sclerosis (MS) disease risk is associated with reduced sun-exposure. This study assessed the relationship between measures of sun exposure (vitamin D [vitD], latitude) and MS severity in the setting of two multicenter cohort studies (nNationMS = 946, nBIONAT = 990). Additionally, effect-modification by medication and photosensitivity-associated MC1R variants was assessed. High serum vitD was associated with a reduced MS severity score (MSSS), reduced risk for relapses, and lower disability accumulation over time. Low latitude was associated with higher vitD, lower MSSS, fewer gadolinium-enhancing lesions, and lower disability accumulation. The association of latitude with disability was lacking in IFN-ß-treated patients. In carriers of MC1R:rs1805008(T), who reported increased sensitivity toward sunlight, lower latitude was associated with higher MRI activity, whereas for noncarriers there was less MRI activity at lower latitudes. In a further exploratory approach, the effect of ultraviolet (UV)-phototherapy on the transcriptome of immune cells of MS patients was assessed using samples from an earlier study. Phototherapy induced a vitD and type I IFN signature that was most apparent in monocytes but that could also be detected in B and T cells. In summary, our study suggests beneficial effects of sun exposure on established MS, as demonstrated by a correlative network between the three factors: Latitude, vitD, and disease severity. However, sun exposure might be detrimental for photosensitive patients. Furthermore, a direct induction of type I IFNs through sun exposure could be another mechanism of UV-mediated immune-modulation in MS.

SNORD116 and growth hormone therapy impact IGFBP7 in Prader-Willi syndrome.

PURPOSE: Prader-Willi syndrome (PWS) is a neurodevelopmental disorder with hypothalamic dysfunction due to deficiency of imprinted genes located on the 15q11-q13 chromosome. Among them, the SNORD116 gene appears critical for the expression of the PWS phenotype. We aimed to clarify the role of SNORD116 in cellular and animal models with regard to growth hormone therapy (GHT), the main approved treatment for PWS. METHODS: We collected serum and induced pluripotent stem cells (iPSCs) from GH-treated PWS patients to differentiate into dopaminergic neurons, and in parallel used a Snord116 knockout mouse model. We analyzed the expression of factors potentially linked to GH responsiveness. RESULTS: We found elevated levels of circulating IGFBP7 in naive PWS patients, with IGFBP7 levels normalizing under GHT. We found elevated IGFBP7 levels in the brains of Snord116 knockout mice and in iPSC-derived neurons from a SNORD116-deleted PWS patient. High circulating levels of IGFBP7 in PWS patients may result from both increased IGFBP7 expression and decreased IGFBP7 cleavage, by downregulation of the proconvertase PC1. CONCLUSION: SNORD116 deletion affects IGFBP7 levels, while IGFBP7 decreases under GHT in PWS patients. Modulation of the IGFBP7 level, which interacts with IGF1, has implications in the pathophysiology and management of PWS under GHT.

Bone degradation machinery of osteoclasts: An HIV-1 target that contributes to bone loss.

Bone deficits are frequent in HIV-1-infected patients. We report here that osteoclasts, the cells specialized in bone resorption, are infected by HIV-1 in vivo in humanized mice and ex vivo in human joint biopsies. In vitro, infection of human osteoclasts occurs at different stages of osteoclastogenesis via cell-free viruses and, more efficiently, by transfer from infected T cells. HIV-1 infection markedly enhances adhesion and osteolytic activity of human osteoclasts by modifying the structure and function of the sealing zone, the osteoclast-specific bone degradation machinery. Indeed, the sealing zone is broader due to F-actin enrichment of its basal units (i.e., the podosomes). The viral protein Nef is involved in all HIV-1-induced effects partly through the activation of Src, a regulator of podosomes and of their assembly as a sealing zone. Supporting these results, Nef-transgenic mice exhibit an increased osteoclast density and bone defects, and osteoclasts derived from these animals display high osteolytic activity. Altogether, our study evidences osteoclasts as host cells for HIV-1 and their pathological contribution to bone disorders induced by this virus, in part via Nef.

Noonan syndrome-causing SHP2 mutants impair ERK-dependent chondrocyte differentiation during endochondral bone growth.

Growth retardation is a constant feature of Noonan syndrome (NS) but its physiopathology remains poorly understood. We previously reported that hyperactive NS-causing SHP2 mutants impair the systemic production of insulin-like growth factor 1 (IGF1) through hyperactivation of the RAS/extracellular signal-regulated kinases (ERK) signalling pathway. Besides endocrine defects, a direct effect of these mutants on growth plate has not been explored, although recent studies have revealed an important physiological role for SHP2 in endochondral bone growth. We demonstrated that growth plate length was reduced in NS mice, mostly due to a shortening of the hypertrophic zone and to a lesser extent of the proliferating zone. These histological features were correlated with decreased expression of early chondrocyte differentiation markers, and with reduced alkaline phosphatase staining and activity, in NS murine primary chondrocytes. Although IGF1 treatment improved growth of NS mice, it did not fully reverse growth plate abnormalities, notably the decreased hypertrophic zone. In contrast, we documented a role of RAS/ERK hyperactivation at the growth plate level since 1) NS-causing SHP2 mutants enhance RAS/ERK activation in chondrocytes in vivo (NS mice) and in vitro (ATDC5 cells) and 2) inhibition of RAS/ERK hyperactivation by U0126 treatment alleviated growth plate abnormalities and enhanced chondrocyte differentiation. Similar effects were obtained by chronic treatment of NS mice with statins. In conclusion, we demonstrated that hyperactive NS-causing SHP2 mutants impair chondrocyte differentiation during endochondral bone growth through a local hyperactivation of the RAS/ERK signalling pathway, and that statin treatment may be a possible therapeutic approach in NS.

HIV-1-Infected Human Macrophages, by Secreting RANK-L, Contribute to Enhanced Osteoclast Recruitment.

HIV-1 infection is frequently associated with low bone density, which can progress to osteoporosis leading to a high risk of fractures. Only a few mechanisms have been proposed to explain the enhanced osteolysis in the context of HIV-1 infection. As macrophages are involved in bone homeostasis and are critical host cells for HIV-1, we asked whether HIV-1-infected macrophages could participate in bone degradation. Upon infection, human macrophages acquired some osteoclast features: they became multinucleated, upregulated the osteoclast markers RhoE and ß3 integrin, and organized their podosomes as ring superstructures resembling osteoclast sealing zones. However, HIV-1-infected macrophages were not fully differentiated in osteoclasts as they did not upregulate NFATc-1 transcription factor and were unable to degrade bone. Investigating whether infected macrophages participate indirectly to virus-induced osteolysis, we showed that they produce RANK-L, the key osteoclastogenic cytokine. RANK-L secreted by HIV-1-infected macrophages was not sufficient to stimulate multinucleation, but promoted the protease-dependent migration of osteoclast precursors. In conclusion, we propose that, by stimulating RANK-L secretion, HIV-1-infected macrophages contribute to create a microenvironment that favors the recruitment of osteoclasts, participating in bone disorders observed in HIV-1 infected patients.

Decreased IGF-1 concentration during the first trimester of pregnancy in women with normal somatotroph function.

INTRODUCTION: A decrease of insulin-like growth factor-I levels (IGF-I) has been reported during the first trimester of pregnancy in women with acromegaly before the secretion of placental growth hormone (GH) progressively increases IGF-1 concentration. STUDY DESIGN: To evaluate variations of concentrations of IGF-1, insulin-like growth factor (IGF)-binding protein-3 (IGF-BP3) and GH during the first trimester of pregnancy in women with normal somatotroph function. PATIENTS AND METHODS: Sixteen women (median age 31 years) with as who were followed for benign thyroid disorders (n = 15) or prolactin-secreting microadenoma (n = 1) were evaluated before and in the first trimester of pregnancy. Serum concentrations of GH, IGF-1, IGF-BP3, TSH and estradiol (E2) were measured before and in the first trimester (5.4 ± 2.2 weeks of gestation). RESULTS: Before pregnancy, somatotroph and thyroid functions (median TSH 1.2 mU/L) were normal in all women. At the first trimester IGF-1 levels decreased significantly (before = 210 ng/mL, first trimester = 145 ng/mL, p < 0.001) with no significant change in GH (before = 1.5 ng/mL, first trimester = 0.84 ng/mL) or IGF-BP3 levels (before = 2.3 ng/mL, first trimester = 2.2 ng/mL), while estradiol levels increased significantly (before = 46.5 pg/100 mL, first trimester = 448.5 pg/100 mL, p < 0.001). CONCLUSION: In women with normal somatotroph function, IGF-1 levels decrease in the first trimester of pregnancy without changes in GH or IGF-BP3 levels. These results confirm liver resistance to GH as a consequence of the physiological increase of estrogens during the first trimester.

Bone defects in LPA receptor genetically modified mice.

LPA and LPA(1) have been shown to increase osteoblastic proliferation and differentiation as well as activation of osteoclasts. Cell and animal model studies have suggested that LPA is produced by bone cells and bone tissues. We obtained data from invalidated mice which support the hypothesis that LPA(1) is involved in bone development by promoting osteogenesis. LPA(1)-invalidated mice demonstrate growth and sternal and costal abnormalities, which highlights the specific roles of LPA(1) during bone development. Microcomputed tomography and histological analysis demonstrate osteoporosis in the trabecular and cortical bone of LPA(1)-invalidated mice. Moreover, bone marrow mesenchymal progenitors from these mice displayed decreased osteoblastic differentiation. Infrared analysis did not indicate osteomalacia in the bone tissue of LPA(1)-invalidated mice. LPA(1) displays opposite effects to LPA(4) on the related G proteins G(i) and G(s), responsible for decrease and increase of the cAMP level respectively, which itself is essential to the control of osteoblastic differentiation. The opposite effects of LPA(1) and LPA(4) during osteoblastic differentiation support the possibility that new pharmacological agents derived from the LPA pathways could be found and used in clinical practice to positively influence bone formation and treat osteoporosis. The paracrine effect of LPA is potentially modulated by its concentration in bone tissues, which may result from various intracellular and extracellular pathways. The relevance of LPA(1) in bone remodeling, as a receptor able to influence both osteoblast and osteoclast activity, still deserves further clarification. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.

DP2, a Carbohydrate Derivative, Enhances In Vitro Osteoblast Mineralisation.

Bone fracture healing is a complex biological process involving four phases coordinated over time: hematoma formation, granulation tissue formation, bony callus formation, and bone remodelling. Bone fractures represent a significant health problem, particularly among the elderly population and patients with comorbidities. Therapeutic strategies proposed to treat such fractures include the use of autografts, allografts, and tissue engineering strategies. It has been shown that bone morphogenetic protein 2 (BMP-2) has a therapeutic potential to enhance fracture healing. Despite the clinical efficacy of BMP-2 in osteoinduction and bone repair, adverse side effects and complications have been reported. Therefore, in this in vitro study, we propose the use of a disaccharide compound (DP2) to improve the mineralisation process. We first evaluated the effect of DP2 on primary human osteoblasts (HOb), and then investigated the mechanisms involved. Our findings showed that (i) DP2 improved osteoblast differentiation by inducing alkaline phosphatase activity, osteopontin, and osteocalcin expression; (ii) DP2 induced earlier in vitro mineralisation in HOb cells compared to BMP-2 mainly by earlier activation of Runx2; and (iii) DP2 is internalized in HOb cells and activates the protein kinase C signalling pathway. Consequently, DP2 is a potential therapeutical candidate molecule for bone fracture repair.

Diagnostic yield of bone fragility gene panel sequencing in children and young adults referred for idiopathic primary osteoporosis at a single regional reference centre.

AIM: To describe the presenting features, bone characteristics and molecular genetics in a large monocentric cohort of children and young adults with idiopathic primary osteoporosis. METHODS: Sixty-six patients (19 children, 47 adults; 28 males, 38 females; age at referral: 3.8 to 65 years) diagnosed with primary osteoporosis were included in this study; patients with features of osteogenesis imperfecta or other known syndromes associated with osteoporosis were excluded. For each patient, the following data were collected by retrospective chart review: family and personal history of fracture and osteoporosis, mineral homeostasis parameters and markers of bone formation and resorption, bone mineral density (BMD) of the lumbar spine (LS-BMD), the total body less head (TB-BMD), and total hip levels (TH-BMD) measured by DXA. As part of the initial assessment process, a bone fragility gene panel sequencing was performed in all of these patients. RESULTS: There was a higher predominance of males in the children (63%) and of females in the adults (66%) (p = 0.030). Compared to the adults, the children had a significantly lower frequency of vertebral fractures (26 vs 57%, p = 0.022) and a higher frequency of peripheral fractures (84 vs 53%; p = 0.019). Bone fragility gene panel sequencing allowed the identification of the heterozygous pathogenic variant in 27% of patients (most frequently in LRP5, WNT1 and COL1A1 or 2 genes) and the heterozygous p.(Val667Met) LRP5 variant in 11% of them. The frequency of pathogenic variants tended to be higher in the children compared to the adults without reaching statistical significance (42 vs 19%; p = 0.053). The frequency of the p.(Val667Met) LRP5 variant was similar in children and adults. No significant differences were found regarding the various clinical, biological and radiological characteristics of the patients according to genotype. CONCLUSION: In this study, we reported the presenting features and bone characteristics in a large cohort of children and young adults with idiopathic primary osteoporosis. Bone fragility gene panel sequencing allowed the identification of genetic variants in a significant proportion of these patients. Molecular diagnosis in these patients is important in order to be able to offer genetic counselling and organise patient management.

Is ghrelin a biomarker of early-onset scoliosis in children with Prader-Willi syndrome?

BACKGROUND: Adolescents with idiopathic scoliosis display high ghrelin levels. As hyperghrelinemia is found in patients with PWS and early-onset scoliosis (EOS) is highly prevalent in these patients, our aims were to explore (1) whether ghrelin levels differ between those with and without EOS and correlate with scoliosis severity, and (2) whether ghrelin levels in the first year of life are associated with the later development of EOS. METHODS: We used a case control study design for the first question and a longitudinal design for the second. Patients with PWS having plasma ghrelin measurements recorded between 2013 and 2018 in our database were selected and 30 children < 10 years old with EOS and 30 age- and BMI-matched controls without EOS were included. The Cobb angle at diagnosis was recorded. In addition, 37 infants with a ghrelin measurement in the first year of life were followed until 4 years of age and assessed for EOS. Total ghrelin (TG), acylated (AG) and unacylated ghrelin (UAG), and the AG/UAG ratio were analyzed. RESULTS: EOS children had an AG/UAG ratio statistically significantly lower than controls. The Cobb angle was positively correlated with TG and UAG. TG and AG in the first year of life were higher in infants who later develop EOS without reaching a statistically significant difference. CONCLUSIONS: Our results suggest that ghrelin may play a role in the pathophysiology of EOS in PWS. Higher ghrelinemia in the first year of life required careful follow-up for EOS.

Ghrelin uses the GHS-R1a/Gi/cAMP pathway and induces differentiation only in mature osteoblasts. This ghrelin pathway is impaired in AIS patients.

We have examined the Acylated Ghrelin (AG)/Gi pathway in different human osteoblastic cell lines. We have found that: 1) AG induces differentiation/mineralization only in mature osteoblasts; 2) the expression of GHS-R1a increases up to the mature cell stage, 3) the action is mediated via the GHS-R/Gi/cAMP pathway only in mature osteoblasts, and 4) osteoblastic cells from adolescent idiopathic scoliosis (AIS) are resistant to the AG/Gi/cAMP pathway. Altogether, these results suggested that AG uses the GHS-R1a/Gi/cAMP pathway to induce differentiation in mature osteoblasts only. This pathway is impaired in AIS osteoblasts. Understanding AG-specific pathways involved in normal and pathological osteoblasts may be useful for developing new treatments for pathologies such as AIS or osteoporosis.

Expression of the type 1 lysophosphatidic acid receptor in osteoblastic cell lineage controls both bone mineralization and osteocyte specification.

Lysphosphatidic acid (LPA) is a major natural bioactive lipid mediator whose biological functions affect multiple organs. These include bone as demonstrated by global Lpar1-knockout mice (Lpar1-/-) which present a bone growth defect. LPA acts on all bone cells including osteoblasts, that are responsible for bone formation, and osteoclasts, which are specialized cells that resorb bone. LPA appears as a potential new coupling molecule during bone remodeling. LPA1 is the most ubiquitous LPA receptor among the six LPA receptor family members (LPA1-6). To better understand the specific role of LPA via its receptor LPA1 in osteoblastic cell lineage we generated osteoblast-specific Lpar1 knockout mice (Lpar1-∆Ob) by crossing Lpar1flox/flox and Osx:Cre+ mouse lines. Lpar1-∆Ob mice do not recapitulate the bone defects of Lpar1-/- mice but revealed reduced bone mineralization and decreased cortical thickness, as well as increased bone porosity associated with an augmentation in the lacunae areas of osteocyte and their apoptotic yield. In vitro, primary Lpar1-∆Ob and immortalized cl1-Ob-Lpar1-/- osteoblasts revealed a remarkable premature expression of alkaline phosphatase, reduced cell proliferation associated with decreased YAP-P nuclear accumulation, and reduced mineralization activity. Osteocyte specification is markedly impaired as demonstrated by reduced expression of early (E11) and late (DMP1, DKK1, SOST) osteocyte markers ex vivo in enriched osteocytic fractions of Lpar1-∆Ob mouse bone explants. In addition, E11 expression and dendrite formation induced by FGF2 are markedly impaired in both primary Lpar1-∆Ob and immortalized cl1-Ob-Lpar1-/- osteoblasts. Taken together these results suggest a new role for LPA in bone mass control via bone mineralization and osteocyte function.

Hypophosphatasia may lead to bone fragility: don't miss it.

Hypophosphatasia is an inheritable disorder characterised by defective bone mineralisation due to the impaired activity of tissue-non-specific alkaline phosphatase (AP). Clinical presentation ranges from stillbirth without mineralised bone to pathological fractures in late adulthood. During childhood, the main manifestations include rickets, growth delay and dental problems. Fractures and bone pain usually characterise the adult form. A 9-year-old girl was referred for repetitive fractures after minimal trauma. She had normal growth, normal sclerae, no rickets and minimal dental abnormalities. Her sister had also presented fractures. The proband, her sister and mother had low total and bone-specific AP levels and E435K mutation in exon 12 of the liver/bone/kidney AP gene. Low AP levels must lead to genetic analysis. Bone fragility and repetitive fractures may be symptoms of hypophosphatasia in childhood, which must not be neglected. Associated factors such as vitamin D or calcium deficiency must be prevented. In conclusion, hypophosphatasia must not be forgotten as an aetiological factor of repetitive fractures or bone pain in children and AP activity should be checked accurately.

Hyperghrelinemia precedes obesity in Prader-Willi syndrome.

BACKGROUND: High plasma ghrelin levels have been reported in Prader-Willi syndrome (PWS). However, little is known about plasma ghrelin in these children during the first years of life characterized by a failure to thrive. OBJECTIVE: The objective of the study was to investigate total plasma ghrelin levels in children with PWS and controls from 2 months to 17 years. SUBJECTS AND METHODS: Forty children with PWS [24 boys, 16 girls, median age 3.6 yr, median body mass index (BMI) Z-score 0.3] were compared with 84 controls (57 boys, 27 girls, median age 4.2 yr median BMI Z-score 0.1). Children were then divided into two groups according to age and GH treatment. RESULTS: Median plasma ghrelin levels were significantly higher in children with PWS, compared with controls at any age (568 vs. 173, P < 0.0001) and decreased with age in both groups (P < 0.0001). In the whole group of PWS, we found an inverse relationship between ghrelin and BMI Z-score, insulin, homeostasis model assessment insulin resistance index, leptin, and lean mass. Plasma ghrelin levels were higher in children with PWS than controls, both in the youngest children below 3 yr who were not receiving GH (771 vs. 233, P < 0.0001) and in the children older than 3 yr, all of whom were treated with GH (428 vs. 159, P < 0.0001). CONCLUSIONS: Plasma ghrelin levels in children with PWS are elevated at any age, including during the first years of life, thus preceding the development of obesity.

Pharmacodynamic effects of cinacalcet after kidney transplantation: once- versus twice-daily dose.

BACKGROUND: In the setting of kidney transplantation, cinacalcet has been given, mainly, once daily, but also twice daily. The aims of this prospective study were to assess the acute pharmacodynamic effect of cinacalcet administrated once or twice daily to kidney transplant patients with normal renal function and persisting hypercalcaemia due to hyperparathyroidism and to evaluate 1-year efficacy and tolerance of cinacalcet given at a dose of 30 mg b.i.d. METHODS: Eleven patients, who received a transplant 6 (6-59) months previously, were included in the study. A first kinetic was done after administration of 60 mg of cinacalcet at 8 a.m. After a washout period of 1 week, the second kinetic was performed with cinacalcet given at 30 mg b.i.d within a 12-h period. RESULTS: During both kinetics, serum calcium (sCa), ionized calcium (sCa(2+)), albumin-corrected Ca and parathyroid hormone (PTH) levels decreased significantly. At 24 h after the second kinetic, sCa(2+) was significantly lower. After 1 year of cinacalcet treatment, given at the dose of 30 mg b.i.d., there was a significant decrease in sCa, sCa(2+), PTH levels and calcium x phosphorus (Ph) product. In contrast, Ph levels increased significantly. There was no significant change in renal function. CONCLUSION: Once- or twice-daily acute administration of cinacalcet to kidney-transplant patients has similar efficacy. One-year administration of cinacalcet, given as two daily doses, is safe and efficient.

DKK1 and sclerostin are early markers of relapse in multiple myeloma.

Recent studies have shown that Dickkopf-related protein (DKK1) and sclerostin decrease when a complete response (CR) is obtained after chemotherapy in myeloma multiple (MM). To study variations in DKK1, sclerostin and P1NP in patients treated for MM, between complete response (CR) and relapse, we carried out a prospective study ancillary to the IFM 2009 protocol (IFM). The aim of IFM was to compare progression-free survival between patients treated with chemotherapy with or without transplantation. We selected 69 patients who reached CR and relapsed. We assayed by ELISA: DKK1, sclerostin and P1NP at 3 end points T1: CR, T2: 4 months before relapse and T3: relapse. There was a significant increase in DKK1 and sclerostin between T1, T2 and T3. (DKK1 medians (IQR): T1 = 30 pmol/l (20.4-41.1), T2 = 37.4 pmol/l (29.8-49.4), p < 0.0001, T3 = 42 pmol/l (33.8-55.5), p < 0.0001 sclerostin medians (IQR): T1 = 0.57 (0.47-0.69), T2 = 0.62 ng/ml (0.53-0.79), p < 0.0001, T3 = n0.64 ng/ml (0.56-0.79), p = 0.005). No significant variation was detected in the levels of P1NP. No association was observed between the characteristics of the MM, or the treatment received and the variation between T1-T3 for DKK1, sclerostin or P1NP. A significant increase in DKK1 and sclerostin was observed four months before relapse.

Cross-sectional associations of plasma vitamin D with cerebral ß-amyloid in older adults at risk of dementia.

BACKGROUND: Vitamin D deficiency is associated with an increased risk of Alzheimer's disease and increased beta-amyloid (Aß) in animals. Hence we sought to investigate the relationship between plasma 25-hydroxyvitamin D (25(OH)D) and cerebral Aß in older adults with subjective memory complaints. METHODS: This is a secondary analysis of the Multidomain Alzheimer Preventive Trial. Participants were 178 dementia-free individuals aged 70 years or older with data on plasma 25(OH)D and cerebral Aß load assessed by [18F]-florbetapir positron emission tomography. Plasma 25(OH)D was measured at study baseline using a commercially available electro-chemiluminescence competitive binding assay. Standard uptake value ratios (SUVRs) were generated using the cerebellum as a reference. Brain regions assessed included the cortex, anterior cingulate, anterior putamen, caudate, hippocampus, medial orbitofrontal cortex, occipital cortex, parietal cortex, pons, posterior cingulate, posterior putamen, precuneus, semioval centre and temporal cortex. Associations were explored using fully adjusted multiple linear regression models. RESULTS: Participants had a mean (SD) age of 76.2 years (4.4) and 59.6% were female. The mean (SD) plasma 25(OH)D level was 22.4 ng/ml (10.8) and the mean (SD) cortical SUVR was 1.2 (0.2). We did not find any cross-sectional associations (p > 0.05) between baseline 25(OH)D levels and Aß in any of the brain regions studied. CONCLUSIONS: These preliminary results suggest that circulating 25(OH)D is not associated with cerebral Aß in older adults. Further longitudinal studies with the measurement of mid-life vitamin D status are required to explore the relationship between vitamin D and Aß accrual over time, thereby circumventing the shortfalls of a cross-sectional study.

Early postnatal soluble FGFR3 therapy prevents the atypical development of obesity in achondroplasia.

BACKGROUND: Achondroplasia is a rare genetic disease is characterized by abnormal bone development and early obesity. While the bone aspect of the disease has been thoroughly studied, early obesity affecting approximately 50% of them during childhood has been somewhat neglected. It nevertheless represents a major health problem in these patients, and is associated to life-threatening complications including increasing risk of cardiovascular pathologies. We have thus decided to study obesity in patients and to use the mouse model to evaluate if soluble FGFR3 therapy, an innovative treatment approach for achondroplasia, could also impact the development of this significant complication. METHODS AND FINDINGS: To achieve this, we have first fully characterized the metabolic deregulations in these patients by conducting a longitudinal retrospective study, in children with achondroplasia Anthropometric, densitometric measures as well as several blood parameters were recorded and compared between three age groups ranging from [0-3], [4-8] and [9-18] years old. Our results show unexpected results with the development of an atypical obesity with preferential fat deposition in the abdomen that is remarkably not associated with classical complications of obesity such as diabetes or hypercholosterolemia. Because it is not associated with diabetes, the atypical obesity has not been studied in the past even though it is recognized as a real problem in these patients. These results were validated in a murine model of achondroplasia (Fgfr3ach/+) where similar visceral adiposity was observed. Unexpected alterations in glucose metabolism were highlighted during high-fat diet. Glucose, insulin or lipid levels remained low, without the development of diabetes. Very interestingly, in achondroplasia mice treated with soluble FGFR3 during the growth period (from D3 to D22), the development of these metabolic deregulations was prevented in adult animals (between 4 and 14 weeks of age). The lean-over-fat tissues ratio was restored and glucose metabolism showed normal levels. Treating Fgfr3ach/+ mice with soluble FGFR3 during the growth period, prevented the development of these metabolic deregulations in adult animals and restored lean-over-fat tissues ratio as well as glucose metabolism in adult animals. CONCLUSION: This study demonstrate that achondroplasia patients develop an atypical obesity with preferential abdominal obesity not associated with classical complications. These results suggest that achondroplasia induces an uncommon metabolism of energy, directly linked to the FGFR3 mutation. These data strongly suggest that this common complication of achondroplasia should be included in the clinical management of patients. In this context, sFGFR3 proved to be a promising treatment for achondroplasia by normalizing the biology at different levels, not only restoring bone growth but also preventing the atypical visceral obesity and some metabolic deregulations.

Identification of a novel mutation in the human growth hormone receptor gene (GHR) in a patient with Laron syndrome.

Deletions and mutations in the growth hormone receptor (GHR) gene are the underlying etiology of Laron syndrome (LS) or growth hormone (GH) insensitivity syndrome (GHIS), an autosomal recessive disease. Most patients are distributed in or originate from Mediterranean and Middle-Eastern countries. Sixty mutations have been described so far. We report a novel mutation in the GHR gene in a patient with LS. Genomic DNA sequencing of exon 5 revealed a TT insertion at nucleotide 422 after codon 122. The insertion resulted in a frameshift introducing a premature termination codon that led to a truncated receptor. We present clinical, biochemical and molecular evidence of LS as the result of this homozygous insertion.