The biomaterial-mediated healing of critical size bone defects in the ovariectomized rat

Summary

This study demonstrated an impaired biomaterial-mediated bone regeneration in a critical sized calvarial defect established within an ovariectomized rat model. Histological and microtomographic evidences were supported by an impaired osteoblastic gene expression and altered expression of estrogen receptors and adipogenic markers.

Introduction

This work aims to address the bone regeneration process in the ovariectomized rat model, by assessing a calvarial critical size defect implanted with a biocompatible bovine bone mineral graft.

Methods

Animals were randomly divided into two groups: Ovx (bilateral ovariectomy) and Sham (control surgery). Following 8 weeks, all animals were submitted to a surgical bicortical craniotomy (5-mm circular critical size defect), which was filled with a biocompatible mineral graft. Animals were euthanized at 1, 3, and 6 months following graft implantation (n?=?10), and results on the orthotopic bone regeneration process were blindly evaluated by radiographic, microtomographic, histological, histomorphometric, and gene expression techniques.

Results

In the attained model, in both Sham and Ovx groups, the bone regenerative process was found to occur in a slow-paced manner. Likewise, a qualitative evaluation of the microtomographic and histological analysis, as well as quantitative data from histomorphometric indexes, revealed reduced bone regeneration in Ovx animals, at the assayed time points. Significant differences were attained at the 3 and 6 months. Gene expression analysis revealed a reduced expression of osteoblastic-related genes and an altered expression of estrogen receptors and adipogenic markers, within the regenerating bone of Ovx animals.

Conclusions

Due to the similarities between the osteoporotic animal model and the human condition of postmenopausal osteoporosis, it might be relevant to consider the potential clinical implication of the osteoporotic condition in the biomaterial-mediated bone tissue healing/regeneration process.     

Collapsin response‐mediator protein 5 (CRMP5) phosphorylation at threonine 516 regulates neurite outgrowth inhibition

The collapsin response‐mediator proteins (CRMPs) are multifunctional proteins highly expressed during brain development but down‐regulated in the adult brain. They are involved in axon guidance and neurite outgrowth signalling. Among these, the intensively studied CRMP2 has been identified as an important actor in axon outgrowth, this activity being correlated with the reorganisation of cytoskeletal proteins via the phosphorylation state of CRMP2. Another member, CRMP5, restricts the growth‐promotional effects of CRMP2 by inhibiting dendrite outgrowth at early developmental stages. This inhibition occurs when CRMP5 binds to tubulin and the microtubule‐associated protein MAP2, but the role of CRMP5 phosphorylation is still unknown. Here, we have studied the role of CRMP5 phosphorylation by mutational analysis. Using non‐phosphorylatable truncated constructs of CRMP5 we have demonstrated that, among the four previously identified CRMP5 phosphorylation sites (T509, T514, T516 and S534), only the phosphorylation at T516 residue was needed for neurite outgrowth inhibition in PC12 cells and in cultured C57BL/6J mouse hippocampal neurons. Indeed, the expression of the CRMP5 non‐phosphorylated form induced a loss of function of CRMP5 and the mutant mimicking the phosphorylated form induced the growth inhibition function seen in wildtype CRMP5. The T516 phosphorylation was achieved by the glycogen synthase kinase‐3β (GSK‐3β), which can phosphorylate the wildtype protein but not the non‐phosphorylatable mutant. Furthermore, we have shown that T516 phosphorylation is essential for the tubulin‐binding property of CRMP5. Therefore, CRMP5‐induced growth inhibition is dependent on T516 phosphorylation through the GSK‐3β pathway. The findings provide new insights into the mechanisms underlying neurite outgrowth.     

Assessment of cyclic changes of microvessels in ovine ovaries using Sonovue contrast-enhanced ultrasound

Our objective was to detect variations of ovarian vascularization that occur in the estrus cycle of the ewe using an IV contrast agent. Five ewes were investigated using contrast-enhanced power Doppler after Sonovue injection at day 0, 3, 5, 10 and 13 of the cycle in two successive estrus cycles. Transvaginal ultrasound monitoring of each ewe was performed after a dose of Sonovue. Parameters derived from the time-intensity curves were compared. Quantification of the enhancement and wash-in period parameters changed significantly between ovaries and between the follicular and luteal periods of the cycle. Uptake time, wash-out time, total time of enhancement and area under the curve were the parameters with the smallest variation between ovaries. Wash-out time and area under the curve are two contrast parameters that did not change with cyclic changes. Thus, using these parameters in premenopausal women will allow more accurate detection of vascular modifications that may be associated with ovarian cancer.     

Co-Infected HIV/Hepatitis Patients Compared With Chronic Liver Patients and Healthy Individuals: Respiratory Assessment Through Surface Electromyography and Spirometry

IntroductionCo-infected HIV and hepatitis subjects are candidates for a liver transplantation because of progressive liver disease. Chronic liver disease, co-infected or not, requires assessment of respiratory function before liver transplantation. The respiratory evaluation of these 2 groups compared with healthy individuals can define deficits, and this can impair a full recovery after transplant surgery.ObjectiveThis study sought to compare the respiratory profile in co-infected patients with chronic liver disease who are candidates for liver transplantation with that of healthy subjects.MethodsThrough respiratory evaluation of flows and lung volumes (spirometry), muscle activity (surface electromyography), and maximum pressure (manovacuometer), 250 people were distributed into 3 groups: 14 patients with HIV and liver disease, 65 healthy subjects, and 171 patients with chronic liver disease. The mean age (years) was respectively 47.5 ± 6.2, 48.3 ± 14.1, and 52.9 ± 8.5. The average body mass index (kg/m²) of the groups was 24.6 ± 4.5, 26.0 ± 3.2, and 28.5 ± 5.3, respectively.ResultsThere was a statistical difference among the groups in the root means square (RMS) rectus abdominis (μV) (P = .0016), RMS diaphragm (μV) (P = .0001), maximal inspiratory pressure (cmH₂O) (P = .001), forced exhaled volume at the end of first second (%) (P = .002), and maximal mid expiratory flow 25% to 75% (%) (P = .0001) for the Kruskal-Wallis test. The multivariate analysis among the groups showed that the RMS diaphragm had a tendency to discriminate the co-infected subjects.ConclusionsThe co-infected HIV group showed a muscle deficit of diaphragm and rectus abdominis activity, and the liver disease group showed lower indexes in volumes and respiratory flows.     

Effect of low-level laser therapy on odontoblast-like cells exposed to bleaching agent

The aim of the present study was to evaluate the effect of low-level laser therapy (LLLT) on odontoblast-like MDPC-23 cells exposed to carbamide peroxide (CP 0.01 %–2.21 μg/mL of H₂O₂). The cells were seeded in sterile 24-well plates for 72 h. Eight groups were established according to the exposure or not to the bleaching agents and the laser energy doses tested (0, 4, 10, and 15 J/cm²). After exposing the cells to 0.01 % CP for 1 h, this bleaching solution was replaced by fresh culture medium. The cells were then irradiated (three sections) with a near-infrared diode laser (InGaAsP—780?±?3 nm, 40 mW), with intervals of 24 h. The 0.01 % CP solution caused statistically significant reductions in cell metabolism and alkaline phosphate (ALP) activity when compared with those of the groups not exposed to the bleaching agent. The LLLT did not modulate cell metabolism; however, the dose of 4 J/cm² increased the ALP activity. It was concluded that 0.01 % CP reduces the MDPC-23 cell metabolism and ALP activity. The LLLT in the parameters tested did not influence the cell metabolism of the cultured cells; nevertheless, the laser dose of 4 J/cm² increases the ALP activity in groups both with and without exposure to the bleaching agent.     

Effects of laser irradiation (670-nm InGaP and 830-nm GaAlAs) on burn of second-degree in rats

This study investigated the effects of 670-nm indium gallium phosphide (InGaP) and 830-nm gallium aluminum arsenide (GaAlAs) laser therapy on second-degree burns induced on the back of Wistar rats. Sixty-three male Wistar rats were anesthetized, and second-degree burns were made on their back. The animals were then divided randomly into three groups: control (C), animals treated with 670-nm InGaP laser (LIn), and animals treated with 830-nm GaAlAs laser (LGa). The wound areas were removed after 2, 6, 10, 14, and 18 days of treatment and submitted to structural and morphometric analysis. The following parameters were studied: total number of granulocytes and fibroblasts, number of newly formed blood vessels, and percentage of birefringent collagen fibers in the repair area. Morphometric analysis showed that different lasers 670-nm InGaP and 830-nm GaAlAs reduced the number of granulocytes and an increase of newly formed vessels in radiated lesions. The 670-nm InGaP laser therapy was more effective in increasing the number of fibroblasts. The different treatments modified the expression of VEGF and TGF-β1, when compared with lesions not irradiated. The different types of light sources showed similar effects, improved the healing of second-degree burns and can help for treating this type of injury. Despite the large number of studies with LLTI application in second-degree burns, there is still divergence about the best irradiation parameters to be used. Further studies are needed for developing a protocol effective in treating this type of injury.     

Real-world outcomes following 12 months of intravitreal aflibercept monotherapy in patients with diabetic macular edema in France: results from the APOLLON study

Graefe's Archive for Clinical and Experimental Ophthalmology - To report the effectiveness of intravitreal aflibercept (IVT-AFL) treatment for diabetic macular edema (DME) in French clinical...