Identification of new single nucleotide polymorphisms affecting total number born and candidate genes related to ovulation rate in Chinese Erhualian pigs

The Chinese Erhualian pig has the highest record for litter size in the world. However, the genetic mechanism of its high prolificacy remains poorly understood. In our study, large phenotypic variations in litter size were found among Erhualian sows. Significant differences in total number born (TNB) and corpora lutea numbers were observed between sows with high and low estimated breeding values (EBVs) for TNB. To identify single nucleotide polymorphisms (SNPs) associated with TNB, a selective genomic scan was conducted on 18 sows representing the top 10% and 18 sows representing the bottom 10% of EBVs of 177 sows using Illumina Porcine SNP60 genotype data. Genome-wide fixation coefficient (F_ST ) values were calculated for each SNP between the high- and low-EBV groups. A total of 154 SNPs were significantly differentiated loci between the two groups. Of the top 10 highest F_ST SNPs, rs81399474, rs81400131 and rs81405013 on SSC8 and rs81434499 and rs81434489 on SSC 12 corresponded to previously reported QTL for litter size. The other five SNPs, rs81367039 on SSC2, rs80891106 on SSC7, rs81477883 on SSC12 and rs80938898 and rs80971725 on SSC14, appeared to be novel QTL for TNB. Significant associations between rs81399474 on SSC8 and TNB were confirmed in 313 Erhualian sows. Forty genes were identified around the top 10 highest F_ST SNPs, of which UCHL1, adjacent to rs81399474, and RPS6KB1 and CLTC, adjacent to rs81434499, have been reported to affect the ovulation rate in pig. The findings can advance understanding of the genetic variations in litter size of pigs.

Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe

A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.

Prospective Randomized Study of Sarpogrelate Versus Clopidogrel-based Dual Antiplatelet Therapies in Patients Undergoing Femoropopliteal Arterial Endovascular Interventions: Preliminary Results

Background:

Sarpogrelate is a selective 5-hydroxytryptamine (5-HT) receptor subtype 2A antagonist which blocks 5-HT induced platelet aggregation and proliferation of vascular smooth muscle cells. We compared the efficacy of sarpogrelate-based dual antiplatelet therapies for the prevention of restenosis and target lesion revascularization (TLR) rates comparing with that of clopidogrel after percutaneous endovascular interventions (EVIs) of femoropopliteal (FP) arterial lesions.

Methods:

This prospective, multicenter, randomized clinical trial recruited a total of 120 patients with successful EVI of FP lesions at seven centers across China between January 2011 and June 2012. Patients were randomized to receive either sarpogrelate (100 mg trice daily for 6 months, n = 63) or clopidogrel (75 mg once daily for 6 months, n = 57). All patients also received oral aspirin (100 mg once daily for 12 months). Clinical follow-up was conducted up to 12 months postprocedure.

Results:

There was no significant difference between the two groups in basic demographic data. The restenosis rate was higher in the clopidogrel group (22.80%) than in sarpogrelate group (17.50%), but there was no significant difference between these two groups (P = 0.465). The TLR rate, ipsilateral amputation rate, mortality in all-cause and bleeding rate were also similar in the two groups (P > 0.05).

Conclusions:

Aspirin plus sarpogrelate is a comparable antithrombotic regimen to aspirin plus clopidogrel after EVI of FP arterial lesions. Dual antiplatelet therapies might play an important role in preventing restenosis after successful EVI of FP lesions.

Evaluation in vivo of autologous cell derived vein grafts based on tissue engineering concept

AIM

Aim of the study was to construct and evaluate of autologous cell derived vein grafts based on tissue engineering concept.

METHODS

In this study, we constructed venous grafts (VGs) in 12 days based on tissue engineering concept. We draw out 8-12 mL of bone marrow from the intended recipient canines (N.=8) to culture and expand endothelial progenitor cells (EPCs). After having been labeled with PKH26-GL, the cells were seeded onto the luminal surface of decellularized scaffolds (DSs) with single, rotative method for 4 hours. Following static culture for 24-72 hours, the hybrids were implanted to recipient canine inferior vena cava. Non-seeded DSs (N.=4) were performed as control.

RESULTS

Angiography disclosed that patent number of test (control) group were 7/7 (2/4), 6/6 (2/2) and 4/4 (1/2) at postoperative 10 days, 4 weeks and 12 weeks, respectively. At 12 weeks, confluenced endothelial cells which covered the whole inner luminal surface of the explants were detected. Meanwhile, fibroblasts and α-actin positive cells in the matrices were found. PKH26-GL labeled EPCs sustained on the luminal surface accompanied by newly formed endothelial cells. However, the explants in both groups showed partial stenosis.

CONCLUSION

These results indicate that such constructed VGs based on autologous bone marrow-derived EPCs and porcine DSs are promising and deserve to further improvement and testing.

The fabrication of double layer tubular vascular tissue engineering scaffold via coaxial electrospinning and its 3D cell coculture

A continuous electrospinning technique was applied to fabricate double layer tubular tissue engineering vascular graft (TEVG) scaffold. The luminal layer was made from poly(ɛ-caprolac-tone)(PCL) ultrafine fibers via common single axial electrospinning followed by the outer layer of core-shell structured nanofibers via coaxial electrospinning. For preparing the outer layernano-fibers, the PCL was electrospun into the shell and both bovine serum albumin (BSA) and tetrapeptide val-gal-pro-gly (VAPG) were encapsulated into the core. The core-shell structure in the outer layer fibers was observed by transmission electron microscope (TEM). The in vitro release tests exhibited the sustainable release behavior of BSA and VAPG so that they provided a better cell growth environment in the interior of tubular scaffold wall. The in vitro culture of smooth muscle cells (SMCs) demonstrated their potential to penetrate into the scaffold wall for the 3D cell culture. Subsequently, 3D cell coculture was conducted. First, SMCs were seeded on the luminal surface of the scaffold and cultured for 5 days, and then endothelial cells (ECs) were also seeded on the luminal surface and cocultured with SMCs for another 2 days. After stained with antibodies, 3D cell distribution on the scaffold was revealed by confocal laser scanning microscopy (CLSM) where ECs were mainly located on the luminal surface whereas SMCs penetrated into the surface and distributed inside the scaffold wall. This double layer tubular scaffold with 3D cell distribution showed the promise to develop it into a novel TEVG for clinical trials in the near future.

Experimental study on the construction of small three-dimensional tissue engineered grafts of electrospun poly-ε-caprolactone

Studies on three-dimensional tissue engineered graft (3DTEG) have attracted great interest among researchers as they present a means to meet the pressing clinical demand for tissue engineering scaffolds. To explore the feasibility of 3DTEG, high porosity poly-ε-caprolactone (PCL) was obtained via the co-electrospinning of polyethylene glycol and PCL, and used to construct small-diameter poly-ε-caprolactone-lysine (PCL-LYS-H) scaffolds, whereby heparin was anchored to the scaffold surface by lysine groups. A variety of small-diameter 3DTEG models were constructed with different PCL layers and the mechanical properties of the resulting constructs were evaluated in order to select the best model for 3DTEGs. Bone marrow mononuclear cells were induced and differentiated to endothelial cells (ECs) and smooth muscle cells (SMCs). A 3DTEG (labeled '10-4%') was successfully produced by the dynamic co-culture of ECs on the PCL-LYS-H scaffolds and SMCs on PCL. The fluorescently labeled cells on the 3DTEG were subsequently observed by laser confocal microscopy, which showed that the ECs and SMCs were embedded in the 3DTEG. Nitric oxide and endothelial nitric oxide synthase assays showed that the ECs behaved normally in the 3DTEG. This study consequently provides a new thread to produce small-diameter tissue engineered grafts, with excellent mechanical properties, that are perfusable to vasculature and functional cells.

Meso-cavo-jugular shunt for complicated portal hypertension: a case report with 8 years of follow-up

BACKGROUND

The treatment of portal hypertension caused by an occlusive lesion in the retrohepatic inferior vena cava and terminal portal venules is complicated because both portal and system venous flow are compromised.

METHODS

A 47-year-old woman presented with this issue, and we reasoned that the only way to achieve successful management was to create a meso-cavo-jugular shunt. This patient was referred to us after undergoing a splenectomy for hypersplenism, which made her ascites intractable. She had a retrohepatic vena caval stenosis and noncirrhotic portal hypertension. Percutaneous transluminal angioplasty of the inferior vena cava stenosis failed. She underwent substernal placement of a 14-mm ringed GoreTex graft (WL Gore and Associates, Flagstaff, AZ) with end-to-side connections to the superior mesenteric vein, internal jugular vein, and vena cava.

RESULT

Her ascites resolved, and at follow-up 8 years later her graft was patent.

CONCLUSION

The meso-cavo-jugular shunt can simultaneously decompress both portal and systemic venous systems and is worth considering in the rare circumstance of suprahepatic vena caval obstruction coupled with occlusion of the portal venules.

Sequence organization and evolutionary dynamics of Brachypodium-specific centromere retrotransposons

Brachypodium distachyon is a wild annual grass belonging to the Pooideae, more closely related to wheat, barley, and forage grasses than rice and maize. As an experimental model, the completed genome sequence of B. distachyon provides a unique opportunity to study centromere evolution during the speciation of grasses. Centromeric satellite sequences have been identified in B. distachyon, but little is known about centromeric retrotransposons in this species. In the present study, bacterial artificial chromosome (BAC)-fluorescence in situ hybridization was conducted in maize, rice, barley, wheat, and rye using B. distachyon (Bd) centromere-specific BAC clones. Eight Bd centromeric BAC clones gave no detectable fluorescence in situ hybridization (FISH) signals on the chromosomes of rice and maize, and three of them also did not yield any FISH signals in barley, wheat, and rye. In addition, four of five Triticeae centromeric BAC clones did not hybridize to the B. distachyon centromeres, implying certain unique features of Brachypodium centromeres. Analysis of Brachypodium centromeric BAC sequences identified a long terminal repeat (LTR)-centromere retrotransposon of B. distachyon (CRBd1). This element was found in high copy number accounting for 1.6 % of the B. distachyon genome, and is enriched in Brachypodium centromeric regions. CRBd1 accumulated in active centromeres, but was lost from inactive ones. The LTR of CRBd1 appears to be specific to B. distachyon centromeres. These results reveal different evolutionary events of this retrotransposon family across grass species.

Generating high-brightness electron beams via ionization injection by transverse colliding lasers in a plasma-wakefield accelerator

The production of ultrabright electron bunches using ionization injection triggered by two transversely colliding laser pulses inside a beam-driven plasma wake is examined via three-dimensional particle-in-cell simulations. The relatively low intensity lasers are polarized along the wake axis and overlap with the wake for a very short time. The result is that the residual momentum of the ionized electrons in the transverse plane of the wake is reduced, and the injection is localized along the propagation axis of the wake. This minimizes both the initial thermal emittance and the emittance growth due to transverse phase mixing. Simulations show that ultrashort (~8 fs) high-current (0.4 kA) electron bunches with a normalized emittance of 8.5 and 6 nm in the two planes, respectively, and a brightness of 1.7×10(19) A rad(-2) m(-2) can be obtained for realistic parameters.

Surgical treatment of carotid body tumor: case report and literature review

Carotid body tumors (CBT) are rare chemical receptor tumors. We report nine cases of CBT who were diagnosed at our center during 2004 to 2008 with a literature review. Of these nine patients, eight underwent complete resection, one received palliative resection due to the malignant nature of the tumor, and the other one refused surgery. No perioperative mortality and stroke occurred. During a mean follow up of 2.2 years, no deaths related to CBT occurred. Surgical treatment for CBT is relatively safe. The surgeon should be careful to maintain the integrity of carotid artery, and prevent cerebral ischemia and cranial nerve injuries in order to improve outcome.

Electron bow-wave injection of electrons in laser-driven bubble acceleration

An electron injection regime in laser wake-field acceleration, namely electron bow-wave injection, is investigated by two- and three-dimensional particle-in-cell simulation as well as analytical model. In this regime electrons in the intense electron bow wave behind the first bubble catch up with the bubble tail and are trapped by the bubble finally, resulting in considerable enhancement of the total trapped electron number. For example, with the increase of the laser intensity from 2 × 10(19) to 1 × 10(20) W/cm(2), the electron trapping changes from normal self-injection to bow-wave injection and the trapped electron number is enhanced by two orders of magnitude. An analytical model is proposed to explain the numerical observation.

Note: Absolute calibration of two DRZ phosphor screens using ultrashort electron bunch

This article gives the absolute calibration of two types phosphor screens (DRZ) that were used to detect and characterize electron bunches driven by laser-plasma accelerator. The test was performed with picoseconds electron bunch at a radio frequency linear electron accelerator in Tsinghua University. The photons emitted from DRZ screens showed good linear responses to the charge of incident electron bunch and cosine angular distribution in space. An energy conversional efficiency of effective scintillant matter was also calculated.

Tunable radiation source by coupling laser-plasma-generated electrons to a periodic structure

Near-infrared radiation around 1000 nm generated from the interaction of a high-density MeV electron beam, obtained by impinging an intense ultrashort laser pulse on a solid target, with a metal grating is observed experimentally. Theoretical modeling and particle-in-cell simulation suggest that the radiation is caused by the Smith-Purcell mechanism. The results here indicate that tunable terahertz radiation with tens GV/m field strength can be achieved by using appropriate grating parameters.

Biological artificial vessel graft in distal arterial bypass for treating diabetic lower limb ischemia: a case report

A 68-year-old female patient was treated for unhealed ulcer in the fourth toe of the left foot. Clinical examinations identified severe stenosis of the proximal segment and occlusion of the distal segment of the left anterior tibial artery, and occlusion of the left posterior tibial artery and the peroneal artery. The proximal stenotic segment of the left anterior tibial artery was dilated, but the distal occlusive part failed to be re-canalized. Left anterior tibial artery to dorsal pedal artery bypass was performed on the patient with an epoxide-crosslinked, special radicals antigen-sealed, porcine-derived biological graft; debridement of the left 4th digiti pedis was also performed. Postoperation course was uneventful. The pulse of the left dorsal pedal artery was strong. The ankle brachial index (ABI) increased from 0.60 to 1.09. Warfarin and two antiplatelet drugs were given after the operation. Six months after operation, computed tomographic angiogram (CTA) identified the patent graft.

Gene space dynamics during the evolution of Aegilops tauschii, Brachypodium distachyon, Oryza sativa, and Sorghum bicolor genomes

Nine different regions totaling 9.7 Mb of the 4.02 Gb Aegilops tauschii genome were sequenced using the Sanger sequencing technology and compared with orthologous Brachypodium distachyon, Oryza sativa (rice), and Sorghum bicolor (sorghum) genomic sequences. The ancestral gene content in these regions was inferred and used to estimate gene deletion and gene duplication rates along each branch of the phylogenetic tree relating the four species. The total gene number in the extant Ae. tauschii genome was estimated to be 36,371. The gene deletion and gene duplication rates and total gene numbers in the four genomes were used to estimate the total gene number in each node of the phylogenetic tree. The common ancestor of the Brachypodieae and Triticeae lineages was estimated to have had 28,558 genes, and the common ancestor of the Panicoideae, Ehrhartoideae, and Pooideae subfamilies was estimated to have had 27,152 or 28,350 genes, depending on the ancestral gene scenario. Relative to the Brachypodieae and Triticeae common ancestor, the gene number was reduced in B. distachyon by 3,026 genes and increased in Ae. tauschii by 7,813 genes. The sum of gene deletion and gene duplication rates, which reflects the rate of gene synteny loss, was correlated with the rate of structural chromosome rearrangements and was highest in the Ae. tauschii lineage and lowest in the rice lineage. The high rate of gene space evolution in the Ae. tauschii lineage accounts for the fact that, contrary to the expectations, the level of synteny between the phylogenetically more related Ae. tauschii and B. distachyon genomes is similar to the level of synteny between the Ae. tauschii genome and the genomes of the less related rice and sorghum. The ratio of gene duplication to gene deletion rates in these four grass species closely parallels both the total number of genes in a species and the overall genome size. Because the overall genome size is to a large extent a function of the repeated sequence content in a genome, we suggest that the amount and activity of repeated sequences are important factors determining the number of genes in a genome.

Pulmonary toxicity in mice exposed to low and medium doses of water-soluble multi-walled carbon nanotubes

Carbon nanotubes (CNTs) are a class of new allotrope of carbon. Different functionalized CNTs may vary from their physical and chemical properties to the biological property. In this study, the toxicity of water-soluble taurine multi-walled CNTs (tau-MWNTs), raw MWNTs and positive control crystalline silicon dioxide particles on mouse lungs via intratracheal instillation (i.t.) was investigated. The dosages we used were 0.125, 0.25, 0.5 or 1 mg/kg of tau-MWNTs and raw MWNTs, and 1 mg/kg of silicon dioxide particles; Serum and lungs were collected at 1, 7, 14 or 28 days postexposure. The biochemical and cellular parameters were assessed, which include the ratio of the lung weight and body weight (lung indices), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and angiotensin converting enzyme (ACE) in serum, and malondialdehyde (MDA), reduced glutathione (GSH), total sulfhydryl group (TSH) in lung tissue homogenates as well as the hydroxyproline in lungs. The characteristic recovery of the lung injury at 28 days postexposure was examined by the assessment of LDH, ALP, lung indices, and histopathology. ACE, MDA, GSH, TSH and histopathological changes showed that tau-MWNTs were less toxic than the raw MWNTs. Histopathological and ultrastructural investigation indicated that the acute pulmonary inflammation in lungs alleviated after 7d postexposure, and were greatly recovered within 28d. Meanwhile, the entrapment of tau-MWNTs reduced greatly by the 28d postexposure. Whereas the heavier pathologic changes induced by raw MWNTs lasted 7 days more than that of tau-MWNTs. Notably, no occurrence of granulomas and fibrosis were found in this study both in the two CNTs samples through 28d postexposure. Silicon dioxide particles, on the contrary, produced more severe damage to lungs than CNTs did in lung index, as well as other biochemical and cellular parameters. These findings indicate that water-soluble tau-MWNTs in low and medium doses induce slight and recoverable pulmonary inflammation in mice, and are less toxic than the insoluble raw MWNTs.

Structure effects in angle-resolved high-order above-threshold ionization of molecules

We present energy-resolved angular distributions of photoelectrons generated in above-threshold ionization (ATI) of nonaligned diatomic molecules N2 and O2 in high-intensity short laser pulses, with emphasis on the most energetic part of the spectra. The angular distribution for photoelectrons with energy of 10U(p) (U(p): ponderomotive energy), i.e., the plateau cutoff in ATI spectra, is found to be broader in O2 than in N2. Resorting to the analyses from both an S-matrix theory and an intuitive semiclassical model, we attribute the observation to the effect of the ground state molecular orbital structure on high-energy electron emission in strong-field molecular ionization.

[Tissue engineering of vascular graft from decellularized arterial matrix and mesenchymal stem cells.]

OBJECTIVE

To investigate the method of constructing small-diameter vascular grafts from xenogenic decellularized arterial matrices and mesenchymal stem cells (MSCs).

METHODS

Porcine iliac arteries were decellularized by detergent and trypsin treatment. Histology, mechanical strength and porosity experiments were performed to evaluate the properties of decellularized matrices. MSCs were isolated from bone marrow of dogs and expanded ex vivo. Decellularized matrices were seeded with MSCs and further cultured in a pulsatile bioreactor. Morphological features of the tissue engineered grafts were assayed by HE staining and scanning electron microscopy.

RESULTS

After cell extraction, absence of cellular components and preservation of extracellular matrix were verified. Mechanical strength of decellularized matrices was slightly reduced compared with native arteries. Porosity of decellularized matrices was 94.9%. Decellularized matrices were successfully seeded with MSCs, which grew to a near-confluent monolayer under flow conditions and MSCs were highly elongated and oriented to the flow direction.

CONCLUSION

Small-diameter vascular grafts can be constructed by seeding MSCs onto xenogenic decellularized arterial matrices and culturing in a pulsatile bioreactor.

[Treatment of severe cerebral ischemia in Takayasu's disease with arterial reconstruction]

OBJECTIVE

To evaluate the effect of surgical bypass and to explore the role of transcranial doppler (TCD) during the bypass operation.

METHODS

From March 2003 to February 2008, sixteen patients (4 male and 12 female) with mean age of 32 years old and mean disease course of 7.5 years were treated by surgical procedures. The main clinical presentations were dizziness, headache, vertigo, and visional dysfunction. Variated degree of artery stenoses in the 4 arteries (bilateral carotid and vertebral arteries) were revealed by color doppler ultrasonography and DSA. Eight patients underwent aorto-bi-subclavian arteries prosthetic graft bypass. Three patients underwent aorto-bi-subclavian artery prosthetic graft bypass and graft-unilateral carotid artery bypass with autologous great saphenous vein. Three patients underwent aorta-unilateral subclavian artery-unilateral carotid artery prosthetic graft bypass. Two patients underwent aorta carotid artery bypass with autologous great saphenous vein, of which one patient underwent aortocoronary artery bypass simultaneously. Cerebral blood supply was monitored in 14 patients with transcranial doppler. Unilateral subclavian carotid and femoral carotid artery shunt was used respectively to avoid cerebral ischemia during operation in 2 patients.

RESULTS

Symptoms and signs of cerebral ischemia improved in all patients with effective rate of 100% apart from deflected tongue-protrusion in 3 patients which recovered in 2 weeks after operation. All patients survived and no symptoms recurred at the end of a 2.2 year's follow-up. Unfortunately, two patients developed aneurysm at the anastomosis within 4 years after operation.

CONCLUSIONS

Arterial reconstruction is an effective method for Takayasu's disease with severe cerebral ischemia. TCD monitoring plays an important role during the bypass operation. It can help to determine the revision of blood pressure and prevent postoperative brain reperfusion injury.

In vitro study of endothelial cells lining vascular grafts grown within the recipient's peritoneal cavity

A living-tissue conduit with strong mechanical properties was used to produce small-diameter vessels. To improve blood compatibility, a shear-resistant confluent monolayer endothelium was formed on the luminal surface of the conduit. Under mechanical stimulation induced by pulsatile flow in a bioreactor, abrupt high-flow shear stress of 15.3 +/- 4.6 dynes/cm2 was applied to endothelial cells (ECs) seeded onto the lumen of a living-tissue conduit after 2 days of static culture. Scanning electron microscopy images revealed that most of the ECs were washed off after 3 days of dynamic culture. When shear stress was increased stepwise from 1.5 +/- 0.8 to 15.3 +/- 4.6 dynes/cm2 and applied to the ECs, scanning electron microscopy images of the luminal surface revealed that the confluent monolayer ECs were highly elongated and oriented to the flow direction, similar to findings in natural arteries in vivo. The results indicated that in vitro flow conditions played a key role in determining the durability of the EC layer. Careful design of the bioreactor and careful selection of the culture conditions will greatly improve the chances of producing a useful anti-thrombogenic surface for tissue-engineered small-diameter vessels.

[Surface modification of vascular tissue engineering biomaterial by low temperature plasma with NH3, CO2 and O2]

OBJECTIVE

To study the biocompatibility of poly (hydroxybutyrate-hydroxyvalerate) (PHBV) modified by low temperature plasma with NH3, CO2, and O2 with canine Endothelial cells (ECs) and provide the better materials for blood vessel tissue engineering via surface modification.

METHODS

PHBV was modified by low temperature plasma with NH3, CO2, and O2, for 0, 5, 10, 20, and 30 min respectively, PHBV not modified was used as control group. The contact angle was measured. X-ray photoelectron spectroscopy was used to detect the surface elements. Canine endothelial cells (ECs) were cultured on the surface of PHBV and were stained with fluorescence isothiocyanate (FITC). Their morphological characteristics were observed with fluorescence microscopy, and the cell proliferation was detected with MTT assay.

RESULTS

The surface contents of carbon of the PHBV modified by low temperature plasma with O2 and CO2 were 63.75% and 69.72%, both lower than that before modification (77.97%). The surface contents of oxygen of the PHBV modified by low temperature plasma with O2 and CO2 were 30.72% and 28.48%, both higher than that before modification (21.74%). The surface content of nitrogen of the PHBV modified by low temperature plasma with NH3 was 3.25%, remarkably higher than that before modification (0). The contact angles of different modification groups, especially those of the 5 min groups, were all significantly smaller than that of the unmodified group (P < 0.05 or P < 0.01). Compared with the control group, the cytocompatibility was better in the low temperature plasma modified groups.

CONCLUSION

The surface of PHBV modified by low temperature plasma with NH3, CO2, and O2 has active groups and good biocompatibility, so the surface modification of low temperature plasma with NH3, CO2, and O2 can be a kind of effective method for the tissue engineering blood vessel.

[Preliminary in vivo evaluation of tissue engineered venous grafts fabricated based on endothelial progenitor cells]

OBJECTIVE

To explore the feasibility of the tissue engineered venous grafts (TEVGs) constructed in vitro based on canine autologous bone marrow-derived endothelial progenitor cells (EPCs) and porcine decellularized aortic scaffolds implanted into the canine inferior vena cava.

METHODS

To draw out a volume of 8 - 12 ml of bone marrow from the canine (n = 8), to culture and expand EPCs in vitro using conditioned medium. After labeled with a red fluorescent dye PKH26-GL, the cells were seeded onto the luminal surface of decellularized porcine scaffolds with single, rotative method for 4 h. Following static culture for 24 - 72 h, the hybrids were implanted to replace autologous canine inferior vena cava about 4 cm long. Meantime one femoral artery-venous shunt about 1 cm long was performed. The non-seeded decellularized scaffolds (n = 4) were performed the same as control. Angiography was performed and the hybrids were explanted for morphology and labeled cells' immuno-fluorescence examinations at postoperative 10 d, 4 weeks and 12 weeks, respectively.

RESULTS

The patent number of experiment (control) group were 7/7 (2/4), 6/6 (2/2) and 4/4 (1/2) at postoperative 10 d, 4 weeks and 12 weeks, respectively. At 12 weeks, tightly confluence endothelial cells which covered the whole inner luminal surface of the explants were detected by immunohistochemistry of factor VIII and scanning electron microscopy, while fibrin-based pseudo-intima was detected on the inner luminal surface of matrix in the solo patent dog from the control group. Meanwhile, fibroblasts and alpha-actin positive cells in the matrices were found by transmission electron microscopy and alpha-actin immunohistochemistry. PKH26-GL labeled EPCs sustained on the luminal surface at a rather proportion accompanied by newly formed endothelial cells. However, the explants in both groups showed partial stenosis.

CONCLUSIONS

Such constructed tissue engineered venous graft based on canine autologous bone marrow-derived endothelial progenitor cells and porcine decellularized aortic matrices is promising and deserve to further improvement and testing.