Sertoli细胞与成人胰岛细胞共同培养的研究

目的观察塞尔托利（Sertoli）细胞对体外培养的成人胰岛细胞形态、存活率及功能的影响。方法胰腺、睾丸取自志愿捐赠的成年男性尸体多器官供者,共12例。分离纯化后的成人胰岛细胞分为单独培养组和共同培养组,单独培养组取成人胰岛细胞单独培养,共同培养组为成人胰岛细胞＋Sertoli细胞共同培养,均在RPMI1640培养液培养14d,采用倒置相差显微镜观察胰岛细胞形态,比较两组的胰岛细胞存活率、胰岛素分泌量和胰岛素刺激指数。结果培养14d后,共同培养组胰岛细胞存活率为（90±3）%,较单独培养组的（57±4）%明显提高（P〈0.01）,胰岛细胞的形态亦较单独培养组完整。共同培养组胰岛细胞始终对葡萄糖刺激保持较高的敏感度,而单独培养组胰岛细胞对葡萄糖刺激的敏感度随时间的延长明显降低（P〈0.05）。培养14d后,共同培养组的胰岛素分泌量为（249±12）mIU/L、胰岛素刺激指数为8.15±0.64,而单独培养组则分别为（47±7）mIU/L和1.68±0.34,两组比较差异有统计学意义（均为P〈0.01）。结论成人胰岛细胞与Sertoli细胞共同培养可以提高胰岛细胞的存活率,改善胰岛细胞的功能。     

Coculture of vascular endothelial cells and adipose-derived stem cells as a source for bone engineering

The interaction between vascular endothelial cells (VECs) and osteoblasts (OBs) is the focus of this recent research. Vascular endothelial cells secrete bone morphogenetic protein, which promotes OB differentiation and stimulates OBs and their precursor cells to secrete vascular endothelial growth factor. Vascular endothelial growth factor is important in angiogenesis and angiopoiesis. Cloning studies have shown that adipose-derived stem cells (ADSCs) have the potential to differentiate into fat, bone, cartilage, and skeletal and smooth muscle cells, among others. Adipose-derived stem cells can express multiple growth factors, including vascular endothelial growth factor and hepatocyte growth factor. Our study examined the influence of coculturing VECs and ADSCs on osteogenic differentiation. Cord blood-derived VECs and ADSCs were isolated from rats and characterized with immunofluorescence staining and morphological observation. Coculture of third-generation ADSCs and VECs was induced for 6 weeks. Cell growth was analyzed using a modified MTT assay. Alkaline phosphatase (ALP) and osteocalcin (OC) was analyzed using immunofluorescence staining. When ADSCs and VECs were cocultured, the absorbance of cells gradually increased, reaching a peak on day 12. The highest absorbance was seen in a coculture system with a ratio of ADSCs and VECs of 1:1. The secretion of ALP and OC gradually increased in these cells and was significantly higher than controls (P < 0.01). Coculturing of ADSCs and VECs at a 1:1 ratio gave the highest secretion of ALP and OC at every time point, and was significantly higher than other groups (P < 0.01). Our results indicated that ADSCs can be induced to osteogenic differentiation by VECs in vitro, suggesting a coculture system of VECs and ADSC as a novel source of cells for bone engineering.     

Coculture of hepatocytes with islets

Bioartificial liver support (BAL) systems are potential new therapeutic approaches for use as liver support to prevent nutrient deficiencies, hypoxia, or ischemia before the acquisition of donated organs. To investigate whether islets are beneficial for hepatocyte function and survival, we cocultured BALB/c mouse islets with C57BL/6J hepatocytes to assess hepatocyte viability, function, and apoptosis. We observe cell viability to decrease progressively by 50% from day 0 to day 3 among isolated hepatocytes (group A) and hepatocytes cocultured with islets (group B). However, group A was prone to necrosis and reduced albumin secretion during culture. In contrast, at day 7 group B maintained albumin secretion (0.3351 ± 0.0581 vs 0.1451 ± 0.0329 μg/h/mL; P < .05). Early apoptosis was observed at day 3 among group A but at day 7 in group B. In addition, quantitative analysis of the apoptotic cells revealed group B to show a delayed phenotype of both early and late apoptosis compared with group A. Our results indicated that islets could retain hepatocyte function and delay apoptosis, suggesting that the coculture system is potentially applicable to develop a high-performance BAL.     

Osteogenic differentiation of adipose-derived stromal cells treated with GDF-5 cultured on a novel three-dimensional sintered microsphere matrix

BACKGROUND CONTEXT: It is well known that under the proper conditions multipotential bone marrow stromal cells are capable of osteogenic differentiation. Recently studies have demonstrated that an analogous subpopulation of cells exist within adipose tissue. Although early studies characterizing these adipose-derived stromal (ADS) cells in culture exist, investigations exploring the characteristics and viability of these cells cultured on a three-dimensional sintered microsphere matrix are absent. PURPOSE: To characterize and investigate the viability of ADS cells cultured on bioengineered three-dimensional sintered microsphere matrices (SMM). STUDY DESIGN: Basic science, laboratory study. PATIENT SAMPLE: Sixty SMM total. Six underwent examination by scanning electron microscopy, 18 for cellular viability, 18 for biochemical assay, and 18 for evaluation by gene expression. OUTCOME MEASURES: The SMM were examined under scanning electron microscopy to evaluate for adherence, migration, and proliferation at 7, 14, and 28 days. Cellular viability was assessed using colorimetric assay for mitochondrial dehydrogenases activity in viable cells (MTS [3-(4,5-dimethylthiazol-2-yl)5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay) at each corresponding time point. Osteoblastic differentiation was determined using biochemical assays for alkaline phosphatase activity and gene expression for alkaline phosphatase (ALP), osteocalcin (OC), and core binding factor alpha-1 (Cbfa1). METHODS: Multipotential ADS cells from adult Sprague Dawley rats were isolated and maintained in media. Sintered microsphere matrices of poly(lactide-co-glycolide) [85:15] were prepared using solvent evaporation technique followed by mechanical sieving and fabricated by heating in metal molds. ADS cells were then seeded on the SMM and cultured in media with growth and differentiation factor-5 (GDF-5). Treated samples and controls were evaluated at 7, 14, and 28 days. Statistical significance was set at p<.05. RESULTS: Multipotential ADS cells were capable of being isolated from adipose tissue. Scanning electron microscopy evaluation revealed cells adherent to the scaffold surface in a monolayer by 7 days. Cytoplasmic extensions were seen linking the cells on adjacent microspheres. Migration and proliferation resulting in extension of the cellular elements into the scaffold was apparent by 14 days. MTS confirmed cell viability within the scaffold throughout the 28-day study. Osteoblastic differentiation was confirmed using biochemical assays for alkaline phosphatase activity and gene expression for ALP, OC, and Cbfa1. CONCLUSIONS: This is the first study to investigate the fate of ADS seeded on a three-dimensional sintered microsphere matrix. The results of this study confirm that ADS cells, when treated with GDF-5, are not only capable of adhering to the bioengineered scaffold, but also remain viable and demonstrated the ability to migrate, proliferate, and subsequently undergo osteogenic differentiation under the conditions described. These early findings support the concept that ADS cells cultured on a SMM may serve as a viable alternative to more traditional methods of bone graft materials.     

Relationship between adult dark spermatogonia and secretory capacity of Leydig cells in cryptorchidism

OBJECTIVE: To examine whether hormonal therapy before orchidopexy affects the histology of the testis and to assess the responsiveness of the Leydig cells, as it has been shown that although basal plasma testosterone levels are within the 'normal' range in cryptorchid boys there is an insufficient increase of testosterone after a human chorionic gonadotrophin (hCG) stimulation in approximately 30% of cryptorchid boys. PATIENTS AND METHODS: In all, 55 boys (aged 1-7 years) with a unilateral undescended testis were included in the study and divided into two groups. Group I (32 boys) received hormonal therapy before orchidopexy; 17 boys received a long-acting LHRH analogue (buserelin) administered as a nasal spray in doses of 20 microg/day for 28 days, followed by 1500 IU hCG intramuscularly (i.m.) once a week for 3 weeks, and the remaining 15 received 1500 IU hCG i.m. once a week for 3 weeks. Group II (33 boys) had orchidopexy alone. During orchidopexy biopsies were taken from the undescended and contralateral descended testes of the boys in both groups for histological analyses. Variations in the number of adult dark (Ad) spermatogonia per tubule (Ad/T) were assessed and testosterone levels were measured during the course of the hormonal therapy (before treatment, 14 days after initiation of buserelin administration, 24 h after each hCG injection, and 3 months after cessation of therapy). RESULTS: In group I, 17 boys (53%) had a 'normal' Ad/T after hormonal treatment vs only six (18%) in group II after orchidopexy alone (P = 0.019). In the hormonally treated boys (group I) we compared the testosterone values 24 h after the second injection of hCG (when the response was most pronounced). Those with a normal Ad/T had a mean (sd) testosterone level of 199.5 (97.6) ng/dL vs 99.6 (85) ng/dL in those with an inadequate Ad/T response to hormonal therapy (P < 0.003). CONCLUSION: We have confirmed that there are two subgroups of cryptorchid boys. Patients with a sufficient Leydig cell secretory capacity will have normal testicular histology and Ad spermatogonia count after hormonal treatment. While those with a suboptimal Leydig cell capacity will have a low Ad spermatogonia count and consequently poor prognosis for future fertility, despite successful surgery. As to whether different types and durations of the hormonal therapy in patients with impaired Leydig cell response could lead to improved testicular histology and consequently improved prognosis for future fertility, remains to be answered.     

Expression of Notch pathway components in spermatogonia and Sertoli cells of neonatal mice.

Members of the Notch gene family have been shown to play an important role in the control of cell fate in many developmental systems. We hypothesized that the fate of the male germ line stem cells may also be mediated through the Notch signaling pathway. We therefore sought to determine whether the components of the Notch pathway are expressed in the mouse testis. Western blot analysis revealed the expression of three Notch receptors (Notch 1, Notch 2, and Notch 3), Notch ligands (Jagged 1, Jagged 2, and Delta 1), and presenilin 1 (PS1) in neonatal mouse testis. We then examined their cellular localization by immunohistochemical analysis of cocultures of spermatogonia and Sertoli cells. The 3 Notch receptors were found to be expressed in spermatogonia. Sertoli cells expressed only Notch 2 receptor. Among the Notch ligands, Delta 1 and Jagged 1 were localized exclusively in spermatogonia and Sertoli cells, respectively. PS1 was apparent in both spermatogonia and Sertoli cells. The presence of Notch receptors and Notch ligands in spermatogonia and Sertoli cells indicates that these cells are capable of responding to and eliciting Notch signaling during the process of spermatogenesis. Key words: Cell fate, delta, jagged, presenilin, spermatogenesis.     

Bone formation by osteoblast-like cells in a three-dimensional cell culture

Summary Cells of the clonal osteogenic cell line MC3T3-E1 were seeded onto a three-dimensional matrix of denatured collagen type 1 and cultured for a period of up to 8 weeks. Specimens were analyzed by histological, enzyme histochemical, immunocytochemical, and ultrastructural methods and byin situ hybridization between day 7 and day 56 after seeding. In 56-day cultures, the MC3T3-E1 cells were arranged in a three-dimensional network and formation of bone-like tissue was indicated by calcification of a newly synthesized collagen type I matrix resembling osteoid and surrounding osteocyte-like cells. The differentiating culture showed high expression of osteocalcin and alkaline phosphatase activity. NIH3T3 fibroblasts used as control cells passed through the network of the substrate forming a confluent monolayer underneath. This culture system offers a potentially powerful model for bone formationin vitro and for investigating the osteogenic potential of bone-derived cells.     

Downregulation of Col1a1 induces differentiation in mouse spermatogonia

Col1a1 (one of the subunit of collagen type I) is a collagen, which belongs to a family of extracellular matrix (ECM) proteins that play an important role in cellular proliferation and differentiation. However, the role of Col1a1 in spermatogenesis, especially in the control of proliferation and differentiation of spermatogonial stem cells (SSCs), remains unknown. In this study, we explored effects of downregulation of Col1a1 on differentiation and proliferation of mouse spermatogonia. Loss-of-function study revealed that Oct4 and Plzf, markers of SSC self-renewal, were significantly decreased, whereas the expression of c-kit and haprin, hallmarks of SSC differentiation, was enhanced after Col1a1 knockdown. Cell cycle analyses indicated that two-thirds of spermatogonia were arrested in S phase after Col1a1 knockdown. In vivo experiments, DNA injection and electroporation of the testes showed that spermatogonia self-renewal ability was impaired remarkably with the loss-of-function of Col1a1. Our data suggest that silencing of Col1a1 can suppress spermatogonia self-renewal and promote spermatogonia differentiation.     

A novel approach:successful management of vasectomy reversal with a three-dimensional digital image microscope system

Dear Editor, Microsurgical vasovasostomy,most commonly performed for vasectomy reversal,remains the most successful procedure for restoring patency to the vas d...     

Selective uptake by the Sertoli cells of cytoplasm from normal spermatogonia in the rat testis

Electron microscopical examination of germ cells during their development from early type A spermatogonia to late pachytene spermatocytes showed that small, spherical pseudopodia emerged from type B spermatogonia and, to a lesser degree, from intermediate spermatogonia and early spermatocytes. Serial sections showed that the pseudopodia pinched off from the type B spermatogonia and were engulfed by the adjacent Sertoli cells. Groups of dense bodies were found in the Sertoli cells adjacent to the engulfed islands of germ cell cytoplasm. At a few instances islands of germ cell cytoplasm were seen to fuse with dense bodies in the Sertoli cells. The fate of the cytoplasmic islands is unknown, but phagocytosis by the Sertoli cells may be suggested. The findings indicate a new type of interaction between Sertoli cells and certain classes of spermatogonia.     

Development of a cryopreservation protocol for type A spermatogonia

The aim of this study was to develop a cryopreservation protocol for type A spermatogonia. Testes from 5- to 7-month-old calves were collected, and type A spermatogonia were isolated using two-step enzymatic digestion and Percoll separation. Cells were resuspended in minimum essential medium (MEM) supplemented with 1% bovine serum albumin (BSA) in a final concentration of 6 x 10(6) per mL, and the effects of different cryoprotectants and freezing protocols were tested. Cells frozen/thawed in medium containing 10% fetal calf serum (FCS) and 1.4 M glycerol or dimethyl sulfoxide (DMSO) had a significantly (P <.05) higher percentage of living cells compared to medium with only FCS, whereas DMSO gave a significantly better cell survival rate than glycerol did. An increase in the concentration of FCS in the DMSO-based medium to 20% had no effect on survival after freezing and thawing. Furthermore, inclusion of 0.07, 0.14, or 0.21 M sucrose in DMSO-based medium resulted in a significant improvement of cell survival, cell proliferation in culture, and colonization efficiency in recipient testes. A controlled slow-freezing rate (1 degrees C/min) resulted in significantly (P <.05) more viable cells than fast (5 degrees C/min) freezing. However, noncontrolled-rate freezing, with a comparably low cooling rate, gave even better results than the controlled-rate slow freezing. Cryopreservation in MEM-based medium containing 10% FCS, 10% DMSO, and 0.07 M sucrose using a non-controlled-rate freezing protocol appeared to be a simple and effective way to preserve type A spermatogonia, with a high yield of almost 70% living cells after thawing. Frozen/thawed spermatogonia survived in culture and retained the ability to proliferate as determined by colorimetric and bromodeoxyuridine incorporation assays. To test whether the stem cells among the A spermatogonia retained their ability to colonize the testis of a recipient mouse, bovine spermatogonia were transplanted. This resulted in colonization 2-3 months after transplantation. In conclusion, for the first time, a method specific for cryopreservation of type A spermatogonia, including spermatogonial stem cells was developed, which allows long-term preservation of these cells without apparent harmful effects to their function.     

Comparison of two- and three-dimensional camera systems in laparoscopic performance: a novel 3D system with one camera

Background  

This study evaluated the effects of a three-dimensional (3D) imaging system on laparoscopy performance compared with the conventional 2D system using a novel one-camera 3D system.     

Inflammatory Response to Implant Particulates in a Macrophage/Osteoblast Coculture Model

The purpose of this study was to further define the cellular response to titanium and polymethylmethacrylate (PMMA) particles in aseptic loosening, and to determine if the use of pamidronate may be effective in inhibiting bone resorption associated with this response. Macrophages and osteoblasts were cocultured to simulate the environment around an aseptically loose prosthesis. Macrophages were plated on the bottom of six well plates and osteoblasts were plated on culture dish inserts, and placed into the wells with the macrophages. Incubation of macrophages with PMMA in this system led to release of prostaglandin E (PGE₂), granulocyte macrophage-colony stimulating factor (GM-CSF), and interleukin-6 (IL-6). Incubation with titanium led to release of tumor necrosis factor (TNF) and IL-6. Exposure of calvaria to media from cells exposed to either PMMA or titanium led to release of calcium 45. Incubation of calvaria with pamidronate was able to inhibit release of calcium 45 associated with exposure to the macrophage/osteoblast/particle conditioned medium. Bone resorption at the interface between implant and bone is a consistent feature leading to loosening of orthopedic implants. By inhibiting bone resorption associated with the inflammatory response to implant particulates, pamidronate or other bisphosphonates may have clinical utility in the treatment or prevention or aseptic loosening. Received: 22 December 1995 / Accepted: 3 May 1996     

Bone tissue engineering using novel interconnected porous hydroxyapatite ceramics combined with marrow mesenchymal cells: quantitative and three-dimensional image analysis

We developed fully opened interconnected porous calcium hydroxyapatite ceramics having two different pore sizes. One has pores with an average size of 150 microm in diameter, an average 40-microm interconnecting pore diameter, and 75% porosity (HA150). The other has pores with an average size of 300 microm in diameter, an average 60-100-microm interconnecting pore diameter, and 75% porosity (HA300). Because of its smaller pore diameter, HA150 has greater mechanical strength than that of HA300. These ceramics were combined with rat marrow mesenchymal cells and cultured for 2 weeks in the presence of dexamethasone. The cultured ceramics were then implanted into subcutaneous sites in syngeneic rats and harvested 2-8 weeks after implantation. All the implants showed bone formation inside the pore areas as evidenced by decalcified histological sections and microcomputed tomography images, which enabled three-dimensional analysis of the newly formed bone and calculation of the bone volume in the implants. The bone volume increased over time. At 8 weeks after implantation, extensive bone volume was detected not only in the surface pore areas but also in the center pore areas of the implants. A high degree of alkaline phosphatase activity with a peak at 2 weeks and a high level of osteocalcin with a gradual increase over time were detected in the implants. The levels of these biochemical parameters were higher in HA150 than in HA300. The results indicate that a combination of HA150 and mesenchymal cells could be used as an excellent bone graft substitute because of its mechanical properties and capability of inducing bone formation.