Laura Piacente

High dickkopf-1 levels in sera and leukocytes from children with 21-hydroxylase deficiency on chronic glucocorticoid treatment

Children with 21-hydroxylase deficiency (21-OHD) need chronic glucocorticoid (cGC) therapy to replace congenital deficit of cortisol synthesis, and this therapy is the most frequent and severe form of drug-induced osteoporosis. In this study, we enrolled 18 patients (9 females) and 18 sex- and age-matched controls. We found in 21-OHD patients high serum and leukocyte levels of dickkopf-1 (DKK1), a secreted antagonist of the Wnt/β-catenin signaling pathway known to be a key regulator of bone mass. In particular, we demonstrated by flow cytometry, confocal microscopy, and real-time PCR that monocytes, T lymphocytes, and neutrophils from patients expressed high levels of DKK1, which may be related to the cGC therapy. In fact, we showed that dexamethasone treatment markedly induced the expression of DKK1 in a dose- and time-dependent manner in leukocytes. The serum from patients containing elevated levels of DKK1 can directly inhibit in vitro osteoblast differentiation and receptor activator of NF-κB ligand (RANKL) expression. We also found a correlation between both DKK1 and RANKL or COOH-terminal telopeptides of type I collagen (CTX) serum levels in 21-OHD patients on cGC treatment. Our data indicated that DKK1, produced by leukocytes, may contribute to the alteration of bone remodeling in 21-OHD patients on cGC treatment.

Effects of deferiprone on immune status and cytokine pattern in thalassaemia major

Objective: The present study was undertaken to evaluate the possible occurrence of immunological abnormalities in thalassaemia major patients treated with deferiprone (L1). Methods: Longitudinal observational cohort study. Results: The absolute number of CD8+ lymphocytes was high and the CD4/CD8 ratio low before L1 treatment; these parameters returned to normal after 3 months of L1 treatment. TNF-α, IL-2 and IL-2sRα were elevated before L1 treatment (11.83 ± 1.75, 11.75 ± 3.91, 1,409 ± 621 pg/ml, respectively), while IL-6 was normal (2.58 ± 0.79 pg/ml). After 12 months of treatment, IL-10 was higher than in previous periods, although always within the normal range. TNF-α, IL-2 and IL-2sRα returned to normal after 12, 6, and 3 months of L1 treatment, respectively.

Clinical significance of serum cytokine levels and thrombopoietic markers in childhood idiopathic thrombocytopenic purpura.

BACKGROUND Biological markers useful for defining children with newly diagnosed immune thrombocytopenic purpura (ITP) who are likely to develop the chronic form of the disease are partially lacking. The purpose of this study was to assess the clinical role of both immunological and thrombopoietic markers in children with ITP and correlate their levels with different disease stages. MATERIALS AND METHODS We enrolled 28 children with ITP at the onset of their disease, who were followed-up for a whole year and divided according to whether their disease resolved within the 12 months (n=13) or became chronic (n=15), 11 subjects with chronic ITP off therapy for at least 1 month at the time of enrolment, and 30 healthy matched controls. Serum levels of T helper type 1 and 2 and T regulatory-associated cytokines, such as interferon γ, tumour necrosis factor α, interleukin (IL) 2, IL6, IL10, and thrombopoietin were measured in all children using quantitative immunoenzymatic assays, while reticulated platelets were evaluated by flow cytometric analysis. RESULTS Serum IL10 levels were significantly higher in patients with an acute evolution of ITP than in either healthy controls (p<0.001) or patients with chronic progression of ITP (p<0.05). Reticulated platelet count and thrombopoietin levels were significantly higher in ITP patients at the onset of their disease, whether with acute resolution or chronic progression, than in healthy subjects (p<0.01; p<0.001), but did not differ between the groups of patients. CONCLUSION IL-10 seems to predict the clinical course of ITP, as it is significantly higher at the onset of disease in patients who obtain disease remission in less than 1 year.

Reduced interleukin-5 production by peripheral CD4+ T cells in common variable immunodeficiency patients.

We evaluated the capacity of peripheral CD4+ T helper cells in four Common Variable Immunodeficiency (CVI) patients to secrete interleukin-4 (IL-4) and IL-5. While in control CD4+ T cells, stimulated via CD3 and cultured in presence of IL-2 or IL-15, a 10 fold increased production of IL-5 (146 ± 30; 142 ± 25 pg/ml) was found, a 4 fold increment of this cytokine was, instead, detected in 3 out of 4 CVI patients (34 ± 13; 39 ± 12 pg/ml) (p < 0.05). In conclusion, the reduction of IL-5, involved in the late regulation of B cell differentiation into Ig-secreting plasma cells, may contribute to the defective antibody production in CVI patients.

Growth hormone release during insulin tolerance, Clonidine, arginine and growth hormone releasing hormone tests in short normal children and adolescents

This study was retrospectively performed in 574 short normal children and adolescents [328 underwent insulin tolerance test (ITT), 34 Clonidine test (CLON), 64 arginine test (ARG), 19 GHRH test, 52 ITT+CLON, 30 GHRH+CLON, and 47 ITT+CLON+GHRH) in order to evaluate the effect of pubertal stage on G H response to different tests and to identify the most likely mechanism of action of different stimuli. GH peak was higher during GHRH than in all other tests. Sex or start of pubertal development did not cause any GH peak difference. Low-responder (GH peak <10ng/ml) percentages were similar (ITT = 13.5%, CLON = 13.4%, ARG = 13.2%, GHRH = 10.6%) also when the subjects were divided according to sex and pubertal development. ITT+CLON showed discordant results in 42/99 subjects (30/42 = 71.4% were low-responders to ITT and 12/42 = 28.6% to CLON). GH peak appeared earlier during GHRH (85% <45 min) and later during CLON (78%: 60–120 min) than during all other tests; GH peak during ITT showed a wide variability of time. Negative correlations were found between GH peak during GHRH and chronological age, height and bone age and during CLON and chronological age. In conclusion our data show that these tests have similar GH secretagogue reliability.

High Sclerostin and Dickkopf-1 (DKK-1) serum levels in children and adolescents with type 1 diabetes mellitus

Context Childhood type 1 diabetes mellitus (T1DM) is associated with decreased bone mass. Sclerostin and dickkopf-1 (DKK-1) are Wnt inhibitors that regulate bone formation. Objective To evaluate sclerostin and DKK-1 levels in T1DM children and to analyze the influence of glycemic control on bone health. Design and setting Cross-sectional study conducted at a clinical research center. Participants One hundred and six T1DM subjects (12.2 ± 4 years), 66 on multiple daily injections (MDIs) and 40 on continuous subcutaneous infusion of insulin (CSII), and 80 controls. Results The average bone transmission time (BTT) and amplitude-dependent speed of sound (AD-SoS) z scores were lower in patients with diabetes than in controls. Significantly increased DKK-1 (3593 ± 1172 vs 2652 ± 689 pg/mL; P < 0.006) and sclerostin (29.45 ± 12.32 vs 22.53 ± 8.29; P < 0.001) levels were found in patients with diabetes with respect to controls, particularly in patients on MDI compared with ones on CSII. Glycemic control was improved in CSII patients compared with MDI ones (P < 0.001) and was also associated with significantly higher BMI-SDS (P < 0.002) and BTT z scores (P < 0.02). With adjustment for age, multiple linear regression analysis of DKK-1 and sclerostin as dependent variables showed that levels of glycated hemoglobin, glucose, 25(OH) vitamin D, osteocalcin, and parathyroid hormone; years of diabetes; and BMI-SDS and AD-SoS z score were the most important predictors (P < 0.0001). Conclusions Our study highlighted (1) the high serum levels of DKK-1 and sclerostin in T1DM children and their relationship with altered glycemic control and (2) the effect of CSII on improvement of glycemic control and bone health in T1DM children.

High serum sclerostin levels in children with haemophilia A.

Keywords: sclerostin; haemophilia A; bone mineral density; receptor activator of nuclear factor-κB ligand; osteoprotegerin; DKK1

Mechanisms of enhanced osteoclastogenesis in girls and young women with Turner's Syndrome

Subjects with hypergonadotropic hypogonadism due to Turners syndrome show low cortical mineral density, osteoporosis and risk of fractures. It is not clear if this bone fragility derives from chromosomal abnormalities or is the result of inadequate bone formation due to estrogen deficiency. The aim of this study was to investigate the cellular mechanisms underlying bone fragility in subjects with Turners syndrome before induction of puberty and after hormonal replacement therapy (HRT). For this purpose, we have evaluated the osteoclastogenic potential of non-fractioned and T-cell depleted cultures of peripheral blood mononuclear cells (PBMCs) belonging to girls with Turners syndrome who had not been treated with HRT yet, girls and young women who were on HRT and age-matched controls. Untreated subjects showed high FSH serum levels, whereas the other subjects displayed normal FSH serum levels. T-cell immunophenotype was analyzed through flow cytometry. Biochemical and DXA analyses were performed. Spontaneous osteoclastogenesis in non-fractioned and T-cell depleted cultures of PBMC belonging to girls with high FSH levels was more evident than in cultures of subjects with normal FSH levels. In the former, osteoclastogenesis was sustained by monocytes expressing high levels of c-fms, TNF-α and RANK, and T-cells producing high RANKL and TNF-α; in the latter it was supported by T-cells expressing high RANKL levels. CD4(+)CD25(high) T-cells were reduced in all subjects, whereas CD3(+)/CD16(+)/CD56(+) NKT-cells were increased in those with high FSH levels. High RANKL and CTX levels were detected in the sera. Bone impairment was already detectable by DXA in subjects aged under 10, although it became more evident with aging. In conclusion, our results demonstrated that bone fragility in subjects with Turners syndrome is associated to enhanced osteoclastogenesis. This process seems to be due to high FSH serum levels before HRT, whereas it is caused by high RANKL during HRT.

Osteoclastogenic potential of peripheral blood mononuclear cells in cleidocranial dysplasia.

Cleidocranial dysplasia (CCD) is an autosomal dominant skeletal dysplasia characterized by hypoplastic or aplastic clavicles, dental abnormalities, and delayed closure of the cranial sutures. In addition, mid-face hypoplasia, short stature, skeletal anomalies and osteoporosis are common. We aimed to evaluate osteoclastogenesis in a child (4 years old), who presented with clinical signs of CCD and who have been diagnosed as affected by deletion of RUNX2, master gene in osteoblast differentiation, but also affecting T cell development and indirectly osteoclastogenesis. The results of this study may help to understand whether in this disease is present an alteration in the bone-resorptive cells, the osteoclasts (OCs). Unfractionated and T cell-depleted Peripheral Blood Mononuclear Cells (PBMCs) from patient were cultured in presence/absence of recombinant human M-CSF and RANKL. At the end of the culture period, OCs only developed following the addition of M-CSF and RANKL. Moreover, real-time PCR experiment showed that freshly isolated T cells expressed the osteoclastogenic cytokines (RANKL and TNFα) at very low level, as in controls. This is in accordance with results arising from flow cytometry experiments demonstrating an high percentage of circulating CD4+CD28+ and CD4+CD27+ T cells, not able to produce osteoclastogenic cytokines. Also RANKL, OPG and CTX serum levels in CCD patient are similar to controls, whereas QUS measurements showed an osteoporotic status (BTT-Z score -3.09) in the patient. In conclusions, our findings suggest that the heterozygous deletion of RUNX2 in this CCD patient did not alter the osteoclastogenic potential of PBMCs in vitro.

Mechanisms of Enhanced Osteoclastogenesis in Alkaptonuria

Alkaptonuria (AKU) is a rare disorder characterized by the deficiency of the enzyme homogentisate 1,2-dioxygenase and consequent homogentisate accumulation, which leads to progressive and severe osteoarthopathy starting from the second decade of life. Thus, in AKU patients, bone involvement represents an important clinical issue, which we investigated. Serum levels of receptor activator of NF-κB ligand (RANKL), osteoprotegerin, sclerostin, Dickkopf-1, and bone remodeling markers were measured in nine AKU patients (two children and seven adults) and 22 controls, together with lumbar spine bone mineral density (LS-BMD) and femoral-BMD. In the two AKU children, the average of LS-BMD and femoral-BMD Z-scores were within the normal range, but reduced with respect to the controls. Otherwise, in the adult AKU patients, LS-BMD T-score was inside the normal range, but femoral-BMD T-score reached osteopenic levels. Consistently, in AKU adults, higher RANKL and C-terminal telopeptide of collagen type 1 and lower osteoprotegerin levels were observed than in controls. Otherwise, spontaneous osteoclastogenesis was already evident in peripheral blood mononuclear cell cultures from AKU children, together with a high percentage of circulating osteoclast precursors. Osteoclastogenesis was sustained by the high levels of tumor necrosis factor-α, RANK, RANKL, and LIGHT. In conclusion, the altered osteoclastogenesis was observed already in AKU children, despite the absence of evident injury. Thus, a preventive approach in young patients, targeting osteoclast activity, may prevent the macroscopic bone disease that appears in adult AKU.