Cyclic tensile stretch modulates osteogenic differentiation of adipose-derived stem cells via the BMP-2 pathway

INTRODUCTION

Mechanical forces play critical roles in the development and remodelling process of bone. As an alternative cell source for bone engineering, adipose-derived stem cells (ASCs) should be fully investigated for their responses to mechanical stress and the mechanisms responsible for osteogenic induction in response to mechanical signals.

MATERIAL AND METHODS

We hypothesized that appropriate application of uniaxial cyclic tensile strain to ASCs could increase bone morphogenetic protein-2 (BMP-2) expression and improve osteogenesis of ASCs. To test our hypothesis, ASCs from the same flask of the same donor were subjected to tensile strain with different patterns in order to eliminate the difference of donor site and passage. After surface markers investigation, the osteo-induced ASCs were subjected to uniaxial cyclic tensile stretch with the following two loading patterns: long duration continuous pattern (6 h, 1 HZ, 2000 µɛ) and short duration consecutive pattern (17 min every day for 10 consecutive days, 1 HZ, 2000 µɛ). Then osteogenic related genes were analysed by real-time PCR.

RESULTS

The ASCs were positive for the markers STRO-1, CD90 and CD44 and negative for CD34. Cyclic tensile strain of 6 continuous h' duration significantly increased gene expressions of BMP-2 and Runx2, and depressed OCN mRNA expression. In contrast, mechanical loading of 17 min every day did not significantly affect gene expression of BMP-2, Runx2, OCN or ALP.

CONCLUSIONS

We indicate that ASCs may sense mechanical loading in a duration-dependent manner and cyclic tensile stretch may modulate the osteogenic differentiation of ASCs via the BMP-2 signalling pathway.

Research on promoting periodontal regeneration with human basic fibroblast growth factor-modified bone marrow mesenchymal stromal cell gene therapy

BACKGROUND AIMS

Recently, it has been found that effective periodontal regeneration can be induced by bone marrow mesenchymal stromal cell (BMSC) transplantation or local application of basic fibroblast growth factor (bFGF). The aim of the present study was to assess, in dogs, the efficacy of periodontal regeneration via the delivery of BMSC transfected with bFGF to repair destruction of periodontal tissue.

METHODS

BMSC from dogs were isolated, cultured and purified via density-gradient centrifugation. Polymerase chain reaction (PCR) was employed to clone bFGF cDNA from human periodontal cells, and the product was then ligated into the eukaryotic expression vector pDC316-IREs-EGFP. BMSC transfected with pDC316bFGF-IREs-EGFP were transplanted into root furcation defects of beagle dogs. After 6 weeks, regeneration in defects was assessed via clinical examination, X-ray, histologic observation and micro-CT analysis.

RESULTS

DNA sequence analysis showed that the bFGF sequence of recombinant plasmid pDC316bFGF-IREs-EGFP was consistent with that reported by GeneBank. bFGF expression was detected with Western blotting, and active bFGF in supernatant was also observed. Our animal experiment proved that the regenerating speed of periodontal bone tissue in groups transplanted with BMSC containing the modified bFGF gene was higher than in those transplanted with BMSC alone.

CONCLUSIONS

A successfully constructed eukaryotic expression vector containing human bFGF in pDC316bFGF-IREs-EGFP could produce bioactive bFGF in vitro. bFGF overexpression mediated by the recombinant plasmid pDC316bFGF- IREs-EGFP accelerated periodontal regeneration.

Estrous Cycle‐Dependent Expression of Estrogen Receptor α in Periodontal Tissue

Estrogen receptor alpha (ERalpha) may play important roles in many estrogen physiological effects, but little is known about the fluctuation of ERalpha during the estrous cycle. In this study, the dynamic expression of ERalpha mRNA and protein in periodontal tissue during the estrous cycle were examined. Forty 12-week-old female rats were divided into four groups, based on the estrous cycle stage, and sacrificed. Immunohistochemistry and in situ hybridization were used to detect dynamic changes in ERalpha protein and mRNA in periodontal tissue during the estrous cycle, and data were analyzed by one-way ANOVA and cosinor analysis for temporal patterns. Significant differences (p<0.05) were found in the expression of ERalpha protein and mRNA among the four groups. The expression of ERalpha protein and mRNA exhibited an infradian rhythm with a period of about 120 h (five days). The phase and amplitude differences between ERalpha protein and mRNA were not significant (p>0.05). The results suggest the expression of ERalpha is dynamic during the estrous cycle and that in the future chronobiologic methods should be used to study the mechanism of estrogen effect on periodontal tissue.

[Association of cathepsin L with coronary heart disease and its risk factors]

OBJECTIVE

To explore the relationship of cathepsin L (CatL) with coronary heart disease (CHD), severity of coronary stenosis and risk factors of CHD.

METHODS

A total of 137 CHD patients and 48 controls were included in the study, to determined the serum levels of CatL, high sensitive C reactive protein (hs-CRP), fasting glucose (FBS), total cholesterol, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), apolipoprotein A1(Apo-A1) and apolipoprotein B. All the subjects were invited for a coronary angiography, using the sum of the Gensini scores to assess the severity of coronary artery stenosis.

RESULTS

Serum CatL levels were significantly higher in CHD patients (5.63 +/= 0.12 microg/L) than non-CHD subjects (3.93 +/= 0.22 microg/L, P<0.01). CatL was an independent risk factor of CHD in Logistic regression analysis [Exp(B)=2.341, 95%CI 1.567 approximately 3.496, P<0.01]. Serum CatL levels were associated positively with the Gensini scores(r=0.228, P<0.01); In fact, CatL was an independent correlator of Gensini scores (P<0.05). CatL inversely associated with HDL-C (r=-0.228, P<0.01) and ApoA1(r=-0.187, P<0.05), and positively with FBS(r=0.161, P<0.05).

CONCLUSION

CatL is involved in the pathogenesis of CHD. Serum CatL levels could reflect the severity of coronary luminal narrowings. CatL might participate in glucose and lipid metabolic disorders.

[Ultrasound-guided transvaginal ovarian interstitial laser treatment in patients with polycystic ovary syndrome: a laser dose-finding study]

OBJECTIVE

To evaluate the clinical and endocrine effectiveness of different laser doses for ultrasound-guided transvaginal ovarian interstitial laser treatment in patients with polycystic ovary syndrome (PCOS).

METHODS

Between January 2005 and July 2007, 56 women with clomifene citrate-resistant PCOS selected from the patients who were referred to Shenzhen Maternity and Child Healthcare Hospital with a request for fertility underwent ultrasound-guided transvaginal ovarian interstitial laser treatment. All subjects were randomly divided into four groups of A, B, C and D. In group A, one coagulation point per ovary was done and group B, two points; group C, three points; group D, four to five points. The size of each point was about 10 mm in diameter (the electrical laser was projected persistently for 1-3 min with a power of 3 -5 W). The serum sexual hormone level, ovulation rate and pregnancy rate within six postoperative months were compared among the four groups.

RESULTS

(1) The spontaneous ovulation rates of groups A (0) and B (21%) within six postoperative months were significantly lower than groups C (71% ,P <0. 05) and D (79%, P < 0.01). The accumulative pregnancy rates of group C(43%) and D(36%) for six postoperative months were significantly higher than group A (0; P < 0.01, P < 0.05). Although they were also higher than that of group B, no statistical significance was found (P > 0.05). (2) No statistically significant differences were found among four groups when various preoperative hormone values were compared (P > 0. 05). The mean serum luteinizing hormone (LH), testosterone level and LH/ follicle stimulating hormone (FSH) ratio was significantly lower postoperatively in groups C [(6.3 +/- 2.6) U/L, (2.2 +/- 0.7) nmol/L, 1.1 +/- 0.3] and D [(5.8 +/- 2.5) U/L, (2.1 +/- 0.4) nmol/L, 1.0 +/- 0.4] than in groupsA [(11.9 +/- 3.1) U/L, (3.9 +/- 1.6) nmol/L, 2.1 +/- 0.5] and B [(10.4 +/- 3.9) U/L, (3.3 +/- 1.1) nmol/L, 2.0 +/- 0.6], respectively (P < 0.05). The mean LH, testosterone level and LH/FSH ratio reduced more obviously in groups C (42%, 39% and 42%) and D (53%, 40% and 58%) than in groups A (4%, 9% and 16%) and B (11%, 6% and 5%; P < 0.05). All above-mentioned parameters between groups C and D had no statistical significant difference (P > 0.05).

CONCLUSIONS

One and two intraovarian laser coagulation points per ovary are associated with poor results. Three points per ovary seem to represent the plateau of effective dose for the ovarian interstitial laser treatment. Increasing the dose above it does not improve the outcome.

Radiofrequency catheter ablation of idiopathic ventricular tachycardia and symptomatic premature ventricular contraction originating from valve annulus

BACKGROUND

Radiofrequency catheter ablation (RFCA) has been established as an effective and curative therapy for ventricular tachycardia (VT) and severely symptomatic premature ventricular contraction (PVC) from the outflow tract in structurally normal hearts. This study aimed to investigate electrophysiologic characteristics and effects of RFCA for patients with idiopathic VT and symptomatic PVC originating from the valve annulus.

METHODS

Characteristics of body surface electrocardiogram (ECG) and endocardiogram in a successful RFCA target were analyzed in 16 patients with idiopathic VT and symptomatic PVC originating from the valve annulus. Additionally, the ECG characteristics of VT or PVC were compared with those of manifest Wolff-Parkinson-White (WPW) syndrome originating from the same site of origin in 15 patients.

RESULTS

Thirteen patients were successful, 2 recurrent and 1 failed. The recurrent cases underwent successful ablation the second time guided by the Ensite 3000 mapping system. In all patients with the WPW syndrome, the characteristics of QRS morphology were well matched with those of the VT and PVC that originated from corresponding sites of origin.

CONCLUSIONS

RFCA is an effective curative therapy for VT and symptomatic PVC originating from the valve annulus. There are specific characteristics in ECG and the ablation site could be located by means of the WPW syndrome accessory pathway's algorithm.

[Effects of catheter ablation of ventricular tachycardia and premature ventricular contraction originating from left and right ventricular outflow tracts]

OBJECTIVE

To observe the ECG and electrophysiological characteristic of patients with idiopathic ventricular tachycardia (VT) and premature ventricular contraction (PVC) originating from left (LVOT) and right (RVOT) ventricular outflow tracts and assess the clinical effect of radio frequency catheter ablation (RFCA) on these patients.

METHODS

RFCA was performed in 58 patients (10 with VT and 48 with PVC, 5 patients with VT from RVOT under the guidance of non-contact mapping system Ensite3000). VT or PVC originated from LVOT in 15 patients (12 out of 15 from left sinus of Valsalva) and RVOT in 43 patients.

RESULTS

(1) R wave in II, III, aVF leads was the common characteristics of VT or PVC originated from LVOT and RVOT and difference in wave duration index and R/S-wave amplitude ratio in V(1) or V(2) could be used to define VT and PVC originated from LVOT or RVOT. (2) Ablation was successful in 55 out of 58 patients (9 patients with the 2nd ablation, evaluated as arrhythmia-free at 3 months post ablation without medication) and failed in 3 patients. One patient developed pericardial tamponade during ablation and recovered without complication after related treatments.

CONCLUSIONS

RFCA is an effective, safe and curative therapy for VT or PVC originated from LVOT and RVOT. Non-contact mapping system (Ensite3000) is a safe and reliable tool to guide mapping and ablation in patients with complex VT and unstable hemodynamics.

Mutant ubiquitin found in Alzheimer's disease causes neuritic beading of mitochondria in association with neuronal degeneration

A dinucleotide deletion in human ubiquitin (Ub) B messenger RNA leads to formation of polyubiquitin (UbB)+1, which has been implicated in neuronal cell death in Alzheimer's and other neurodegenerative diseases. Previous studies demonstrate that UbB+1 protein causes proteasome dysfunction. However, the molecular mechanism of UbB+1-mediated neuronal degeneration remains unknown. We now report that UbB+1 causes neuritic beading, impairment of mitochondrial movements, mitochondrial stress and neuronal degeneration in primary neurons. Transfection of UbB+1 induced a buildup of mitochondria in neurites and dysregulation of mitochondrial motor proteins, in particular, through detachment of P74, the dynein intermediate chain, from mitochondria and decreased mitochondria-microtubule interactions. Altered distribution of mitochondria was associated with activation of both the mitochondrial stress and p53 cell death pathways. These results support the hypothesis that neuritic clogging of mitochondria by UbB+1 triggers a cascade of events characterized by local activation of mitochondrial stress followed by global cell death. Furthermore, UbB+1 small interfering RNA efficiently blocked expression of UbB+1 protein, attenuated neuritic beading and preserved cellular morphology, suggesting a potential neuroprotective strategy for certain neurodegenerative disorders.

[Effect of drainage of the cerebrospinal fluid at the acute period of aneurysmal subarachnoid hemorrhage on the formation of hydrocephalus]

OBJECTIVE

To discuss the effect of drainage of the cerebrospinal fluid (CSF) at acute period after aneurysmal subarachnoid hemorrhage (SAH) on the formation of hydrocephalus.

METHODS

Eighty-four patients with aneurysmal SAH were randomly divided into two groups according to therapeutic regimen. Forty-two cases in specific treatment group were given intravascular embolism at the acute period of hemorrhage after a ruptured aneurysm, then CSF was drained immediately. Forty-two cases were in conventional expectant treatment group. Clinical data and incidence of hydrocephalus of specific treatment group and conventional expectant treatment group were analyzed.

RESULTS

Clinical data did not show any differences between two groups, so they could be compared (all P>0.05). The incidence rate of acute hydrocephalus in specific treatment group was 7.14% (3/42 cases), that of subacute hydrocephalus was 4.76% (2/42 cases), and that of chronic hydrocephalus was 16.67% (7/42 cases). The total incidence rate was 28.57%. In conventional expectant treatment group, the incidence rate of acute hydrocephalus was 23.81% (10/42 cases), incidence of subacute hydrocephalus was 9.52% (4/42 cases), and that of chronic hydrocephalus was 35.71% (15/42 cases), and total incidence rate was 69.05%. There was significant difference between specific treatment group and conventional expectant treatment group in incidence of acute and chronic hydrocephalus (acute chi (2)=4.46, chronic chi (2)=3.94, both P<0.05), and there was no difference in subacute hydrocephalus between two groups (chi (2)=0.72, P>0.05), but significant difference was found in total incidence rate between two groups (chi (2)=13.77, P<0.01).

CONCLUSION

Embolization of the intracranial aneurysm with interventional treatment at the acute hemorrhage stage (within 7 days) for the aneurysmal SAH, followed by immediate drainage of CSF can prevent hydrocephalus or alleviate hydrocephalus, and the treatment plays a significant role in the formation and development of hydrocephalus.

Extracellular hmgb1 functions as an innate immune-mediator implicated in murine cardiac allograft acute rejection

Hmgb1, an evolutionarily conserved chromosomal protein, was recently re-discovered to be an innate immune-mediator contributing to both innate and adaptive immune responses. Here, we show a pivotal role for Hmgb1 in acute allograft rejection in a murine cardiac transplantation model. Extracellular Hmgb1 was found to be a potent stimulator for adaptive immune responses. Hmgb1 can be either passively released from damaged cells after organ harvest and ischemia/reperfusion insults, or actively secreted by allograft infiltrated immune cells. After transplantation, allografts show a significant temporal up-regulation of Hmgb1 expression accompanied by inflammatory infiltration, a consequence of graft destruction. These data suggest the involvement of Hmgb1 in acute allograft rejection. In line with these observations, treatment of recipients with rA-box, a specific blockade for endogenous Hmgb1, significantly prolonged cardiac allograft survival as compared to those recipients treated with either rGST or control vehicle. The enhanced graft survival is associated with reduced allograft expression of TNFalpha, IFNgamma and Hmgb1 and impaired Th1 immune response.

Schwann cell graft: A method to promote sensory responses of osseointegrated implants

Osseointegrated dental implants have been widely used in clinics to restore the missing teeth of patients. Since there are no periodontal ligament and associated Ruffini endings in the peri-implant tissues, sensory thresholds of the implant are much higher than those of natural teeth, and its self-protective reflex is quit poor. Implant fracture or aggressive bone loss sometimes occurs because the patient cannot feel the overloads exerted on the implant. Until now, no available method has been issued to solve such a problem. Schwann cell is the glial cell of peripheral nerve system. It has been widely accepted to play indispensable roles during neural development and regeneration. Its mechanism includes forming Büngner's band, producing neurotrophic factors, synthesizing surface cell adhesion molecules, and elaborating basement membrane. Furthermore, Schwann cell is quite important for the periodontal Ruffini endings. Applying these functions of Schwann cells, we put forward a hypothesis that transplanting Schwann cells into the implant site can be a method to promote sensory responses of the dental implants.

[Study of altered expression of annexin IV and human endometrial receptivity]

OBJECTIVE

To explore the association of altered expression of annexin IV in human endometrium during the implantation window and endometrial receptivity.

METHODS

A comparative proteomic strategy, in a combination of two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), was adopted to search for proteome alternations of pre-receptive (day LH + 2) versus receptive (LH + 7) endometria. The location and abundance of the identified differentially expressed protein- annexin IV were analyzed by immunostaining and western blot.

RESULTS

By comparing protein profiles of LH + 2 and LH + 7 samples, we found a protein up-regulated 2.12 times in LH + 7 samples, with a relative molecular weight of 36,000 and an isoelectric point near pH 5.8. It was characterized using mass spectrometry and was identified as annexin IV. Immunohistochemical analysis revealed an altered localization of annexin IV--in the epithelia on day LH + 2, and both in the epithelia and stroma cells on day LH + 7. Protein levels of annexin IV were up-regulated on day LH + 7 compared with that on day LH + 2 by Western blot. Integrated optical density of the object (OPTDI) was 46.249 +/- 32.376 and 249.507 +/- 31.959, respectively (P = 0.004).

CONCLUSIONS

Our study indicates endometrial samples obtained by microbiopsy are available for proteomics studies. It seems possible that the increased expression of annexin IV during the implantation window plays an important role in the morphological differentiation of the uterus to the receptive state.

[A clinical study of immediate dental implant and immediate restoration]

OBJECTIVE

To evaluate the clinical results of immediate implant and immediate restoration and to discuss the applying principles of these techniques.

METHODS

Fourteen cases underwent immediate implant surgery for 37 dental implants immediately after the teeth or roots were extracted. Among them, 6 cases (14 implants) received immediate restoration after implant placement. The second stage operation and final restoration were performed 4 months on average postoperatively, and the mean follow-up time was 22 months.

RESULTS

Two implants from 1 case were lost at 3 weeks after immediate implant and immediate restoration. The rest cases achieved good clinical results. Accumulative 4-year survival rate was 94.6%.

CONCLUSIONS

The result of immediate implant and immediate restoration is predictable if the cases are properly selected.