Hepcidin and iron metabolism associated with cardiometabolic risk factors in children: A case-control study

BACKGROUND AND AIMS

Iron metabolism plays a crucial role in the development of cardiometabolic disease; however, the association between cardiometabolic risk factors (CMRFs) and hepcidin as well as other iron parameters remains unclear in children. The aims of this study were to compare the circulating hepcidin levels and iron metabolism between children with and without CMRFs and to investigate the association between those iron parameters and CMRFs.

METHODS AND RESULTS

A case-control study was conducted among 1126 children aged 7-14 years in the case group (n = 563) with CMRFs and the healthy control group (n = 563). Iron parameters, lipids, and anthropometric characteristics were evaluated. The information on demographics, diet, and physical activities was either children reported or parent reported. Compared with the healthy controls, children with CMRFs had higher levels of hepcidin and lower levels of serum iron, transferrin, and soluble transferrin receptor (sTfR; P < 0.001). Besides, the odds ratios (ORs) for low levels of high-density lipoprotein (HDL) were 2.03, 0.21, and 0.33 in children with higher hepcidin, transferrin, and sTfR levels (P < 0.05). Furthermore, ORs for cardiometabolic risk were 0.50 (95% confidence interval (CI): 0.30-0.85, P < 0.05), 0.22 (95% CI: 0.12, 0.42, P < 0.01) and 0.19 (95% CI: 0.10, 0.36, P < 0.01) in children with higher serum iron, transferrin, and sTfR levels, respectively.

CONCLUSION

The levels of hepcidin were higher, while those of iron, transferrin, and sTfR were lower in children with CMRF. Hepcidin was positively associated with the risk of low HDL levels, whereas transferrin and sTfR levels negatively correlated with the risk of low HDL levels. In addition, serum iron, transferrin, and sTfR levels were negatively associated with cardiometabolic risk.

Chondrocytes Directly Transform into Bone Cells in Mandibular Condyle Growth

For decades, it has been widely accepted that hypertrophic chondrocytes undergo apoptosis prior to endochondral bone formation. However, very recent studies in long bone suggest that chondrocytes can directly transform into bone cells. Our initial in vivo characterization of condylar hypertrophic chondrocytes revealed modest numbers of apoptotic cells but high levels of antiapoptotic Bcl-2 expression, some dividing cells, and clear alkaline phosphatase activity (early bone marker). Ex vivo culture of newborn condylar cartilage on a chick chorioallantoic membrane showed that after 5 d the cells on the periphery of the explants had begun to express Col1 (bone marker). The cartilage-specific cell lineage-tracing approach in triple mice containing Rosa 26(tdTomato) (tracing marker), 2.3 Col1(GFP) (bone cell marker), and aggrecan Cre(ERT2) (onetime tamoxifen induced) or Col10-Cre (activated from E14.5 throughout adult stage) demonstrated the direct transformation of chondrocytes into bone cells in vivo. This transformation was initiated at the inferior portion of the condylar cartilage, in contrast to the initial ossification site in long bone, which is in the center. Quantitative data from the Col10-Cre compound mice showed that hypertrophic chondrocytes contributed to ~80% of bone cells in subchondral bone, ~70% in a somewhat more inferior region, and ~40% in the most inferior part of the condylar neck (n = 4, P < 0.01 for differences among regions). This multipronged approach clearly demonstrates that a majority of chondrocytes in the fibrocartilaginous condylar cartilage, similar to hyaline cartilage in long bones, directly transform into bone cells during endochondral bone formation. Moreover, ossification is initiated from the inferior portion of mandibular condylar cartilage with expansion in one direction.

The Asia proximal femoral nail antirotation versus the standard proximal femoral antirotation nail for unstable intertrochanteric fractures in elderly Chinese patients

BACKGROUND

The best options of internal fixation for unstable intertrochanteric fractures in elderly Chinese patients remain controversial. The Asia proximal femoral nail antirotation (PFNA-II) was specifically designed for Asian patients, which could be more effective than the regular proximal femoral nail antirotation (PFNA). Compared to PFNA, whether PFNA-II is associated with shorter operative time and lower rates of complications is unknown.

HYPOTHESIS

The rate of complications using PFNA-II is lower than PFNA for the treatment of unstable intertrochanteric fractures in elderly Chinese patients, and the operation using PFNA-II is quicker.

MATERIALS AND METHODS

Between June 2008 and December 2011, 188 patients with unstable intertrochanteric fractures treated with the PFNA-II (n=118) or PFNA (n=70) were retrospectively evaluated. Follow-up evaluations were performed at 1, 3, 6, 9 and 12 months, and every year thereafter. According to residual valgus-varus deformation, the quality of the fracture reduction was graded as poor (>10° deformation), acceptable (5° to 10° deformation), or good (<5° deformation). The operative time, intraoperative blood loss, overall time of fluoroscopy, blood transfusion volume, postoperative drainage, length of hospital stay and postoperative complications were recorded.

RESULTS

The mean operative time in the PFNA-II group was significantly shorter than that in the PFNA group (66.25±13.15 vs 79.50±21.12 minutes; P<0.05), intraoperative blood loss was smaller (131.86±69.16 vs 162.14±66.18 mL; P<0.05), and fewer local complications were observed (25% vs 46%; P<0.05). There was no significant difference in the postoperative blood transfusions, overall time of fluoroscopy, postoperative drainage, length of hospital stay, fracture reduction, the position of the implant and tip apex distance between the two groups. At follow-up, no significant difference was found between the two groups in Harris hip score (HHS) (86.19±6.53 vs 85.27±5.47; P>0.05), visual analogue scale (VAS) (0.87±0.85 vs 0.97±0.87; P>0.05).

DISCUSSION

Due to its special design for the Asian population, PFNA-II offers a better match with the Chinese people's proximal femur anatomic structure. This study showed that the rate of complications using PFNA-II is lower than PFNA for the treatment of unstable intertrochanteric fractures in elderly Chinese patients, and the operation time is shorter.

LEVEL OF EVIDENCE

Level III, case control study.

Chitosan/hydroxyapatite hybrid scaffold for bone tissue engineering

BACKGROUND

To favor regeneration following critical bone defect, a combination of autologous bone graft and biomaterials is currently used. Major drawbacks of such techniques remain the availability of the autologous material and the second surgical site, inducing pain and morbidity.

OBJECTIVE

Our aim was to investigate the biocompatibility in vitro of three dimensions hybrid biodegradable scaffolds combining osteoconductive properties of hydroxyapatite and anti-inflammatory properties of chitosan.

METHODS

Hybrid scaffolds were characterized by microscopic observations, equilibrium swelling ratio and overtime weight loss measurements. In vitro studies were performed using primary human bone cells cultured for 7, 14 and 21 days. Cell viability, proliferation, morphology and differentiation through alkaline phosphatase (ALP) activity measurement were assessed.

RESULTS

Characterization of our scaffolds demonstrated porous, hydrophilic and biodegradable characteristics. In vitro studies showed that these scaffolds have induced slight decrease in cell death and proliferation comparing to the culture plastic substrate control condition, as well as increased short term osteoinductive properties.

CONCLUSIONS

In this study, we have provided evidence that our hybrid hydroxyapatite/chitosan scaffolds could be suitable for bone filling.

Osterix couples chondrogenesis and osteogenesis in post-natal condylar growth

Osterix (Osx) is a transcription factor essential for osteoblast differentiation and bone mineralization. Although there are indications that Osx also plays a regulatory role in cartilage, this has not been well-studied. The goal of this study was to define the function of Osx in the post-natal growth of the secondary cartilage at the mandibular condyle. Conditional Osx knockout (cKO) mice that were missing Osx only in cartilage were generated by crossing Osx-loxP mice to Aggrecan-Cre mice. Cre activity was induced by tamoxifen injection twice a week from day 12 to 1 mo of age, and specimens were collected at 1 and 5 mo of age. At 1 mo of age, the condylar hypertrophic chondrocyte zone in the cKO-mice was > three-fold thicker than that in the age-matched control, with little sign of endochondral bone formation. Immunohistochemistry and analysis of histological data revealed a defect in the coupling of chondrogenesis and osteogenesis in the cKO mice. In five-month-old mice examined to address whether late-stage removal of the Cre-deletion event would alleviate the phenotype, the hypertrophic chondrocyte zone in the cKO condyles was considerably larger than in wild-type mice. There were large discrete areas of calcified cartilage in the hypertrophic zone, few signs of endochondral bone formation, and large regions of disorganized intramembranous bone. Analysis of these data further strengthens the notion that Osterix is essential for the coupling of terminal cartilage differentiation and endochondral ossification in mandibular condylar cartilage.

Default network connectivity as a vulnerability marker for obsessive compulsive disorder

BACKGROUND

Aberrant functional connectivity within the default network is generally assumed to be involved in the pathophysiology of obsessive compulsive disorder (OCD); however, the genetic risk of default network connectivity in OCD remains largely unknown.

METHOD

Here, we systematically investigated default network connectivity in 15 OCD patients, 15 paired unaffected siblings and 28 healthy controls. We sought to examine the profiles of default network connectivity in OCD patients and their siblings, exploring the correlation between abnormal default network connectivity and genetic risk for this population.

RESULTS

Compared with healthy controls, OCD patients exhibited reduced strength of default network functional connectivity with the posterior cingulate cortex (PCC), and increased functional connectivity in the right inferior frontal lobe, insula, superior parietal cortex and superior temporal cortex, while their unaffected first-degree siblings only showed reduced local connectivity in the PCC.

CONCLUSIONS

These findings suggest that the disruptions of default network functional connectivity might be associated with family history of OCD. The decreased default network connectivity in both OCD patients and their unaffected siblings may serve as a potential marker of OCD.

MiR-125b inhibits cell biological progression of Ewing's sarcoma by suppressing the PI3K/Akt signalling pathway

OBJECTIVES

Increasing evidence has suggested the close relationship between microRNAs (miRNAs) dysregulation and the carcinogenesis of Ewing's sarcoma (ES), among of which miR-125b has been reported to be decreased in ES tissues recently. Strikingly, ectopic expression of miR-125b could suppress cell proliferation of ES cell line A673, suggesting the tumor suppressor role of miR-125b in ES. However, the other accurate mechanistic functions and relative molecule mechanisms are largely unknown.

MATERIALS AND METHODS

Herein, we completed a series of experiments to investigate the role of miR-125b in Ewing's sarcoma. We restored the expression of miR-125b in ES cell line A673 through transfection with miR-125b mimics. To further understand the role of miR-125b in ES, we detected the effects of miR-125b on the cell proliferation, migration and invasion, cell cycle as well as cell apoptosis.

RESULTS

We found that restored expression of miR-125b in ES cell line A673 inhibited cell proliferation, migration and invasion, arrested cell cycle progression, and induced cell apoptosis. Moreover, bioinformatic prediction suggested the oncogene, phosphoinositide-3-kinase catalytic subunit delta (PIK3CD), was a target gene of miR-125b in ES cells. Further quantitative RT-PCR and western blot assays identified over-expression of miR-125b suppressed the expression of PIK3CD mRNA and protein. PIK3CD participates in regulating the PI3K signaling pathway, which has been reported to play an important role in the development of ES. Suppression of PIK3CD down-regulated the expression of phospho-AKT and phospho-mTOR proteins and inhibited the biologic progression of A673 cells.

CONCLUSIONS

Collectively, these data suggest that miR-125b functions as a tumor suppressor by targeting the PI3K/Akt/mTOR signaling pathway, and may provide potential therapy strategy for ES patients by targeting miRNA expression.

Neuropsychological function and cerebral metabolites in HIV-infected youth

The effects of HIV on brain metabolites and cognitive function are not well understood. Sixteen HIV+youths (15 vertical, 1 transfusion transmissions) receiving combination antiretroviral therapy and 14 age-matched HIV- youths (13-25 years of age) were evaluated with brain two-dimensional (2D) magnetic resonance spectroscopy (MRS) at 3 Tesla (T) and a neuropsychological battery that assessed three cognitive domains (attention/processing speed, psychomotor ability, and executive function). The relationship between brain metabolite ratios and cognitive performance was explored. Compared to HIV- controls, HIV+ subjects had higher sycllo-inositol (Scy)/total creatine (tCr) (+32%, p = 0.016) and higher Scy/total choline (tCho) (+31%, p = 0.018) on 2D-MRS in the right frontal lobe. HIV+ subjects also had higher glutamate (Glu)/tCr (+13%, p = 0.022) and higher Glu/tCho (+15%, p = 0.048) than controls. HIV+ subjects demonstrated poorer attention/processing speed (p = 0.011, d = 1.03) but similar psychomotor and executive function compared to HIV- controls. The attention/processing score also correlated negatively with the ratio of N-acetylaspartate (NAA) to tCr on 2D-MRS (r = -0.75, p = 0.0019) in the HIV- controls, but not in the HIV+ subjects (Fisher's r-z transformation, p < 0.05). Our results suggest that attention/processing speed is impacted by early HIV infection and is associated with right hemisphere NAA/tCr. Scy and Glu ratios are also potential markers of brain health in chronic, lifelong HIV infection in perinatally infected youths receiving antiretroviral therapy.