应用异体脱细胞尿道基质修复尿道缺损

目的探讨应用同种脱细胞尿道基质修复尿道缺损的可行性。方法将14只雄性新西兰兔分为两组，切除实验组长约1.0～1．5cm的尿道，用相应长度脱细胞尿道基质修复；对照组行假手术。术后行尿道造影并取尿道标本作病理检查。结果12只实验兔的脱细胞基质移植物没有移位。除2例狭窄、2例尿瘘外，其余满意效果。病理检测示，术后3周尿道管腔上皮化，6个月基质中平滑肌及血管再生明显。结论同种脱细胞尿道基质材料可以修复兔尿道部分缺损。     

异种膀胱无细胞基质替代尿道的研究

目的探讨异种膀胱无细胞基质(ACM)管状替代尿道的可行性。方法19只成年雄性新西兰白兔分成3组：A组3只，为假手术对照组；B组10只，切除一段1．0cm尿道；C组6只，切除一段3．5～4．0cm尿道，之后应用已经事先制备好的异种膀胱ACM制成相当长度的管状替代被切除的尿道。术后1、2、4、8、16周动态观察替代尿道的尿道上皮、平滑肌和血管的再生情况。结果所有实验动物在术后7d拔除尿管后都恢复了自主排尿，没有排斥、尿瘘、感染等并发症发生。组织学检查显示实验组术后2周尿道上皮再生良好，4周完全覆盖尿道内腔，术后8周平滑肌见于近吻合口处，平滑肌生长缓慢，观察期内未能覆盖全长尿道。尿道造影未见明显尿道狭窄和憩室。结论异种膀胱ACM是一种良好的尿道修复和替代的材料。     

脱细胞基质在尿道组织工程中的应用

脱细胞基质是经过物理化学方法 脱去组织中抗原成分且富含胶原的一种材料,在尿道修复和重建中,显示了极其广泛的应用前景.     

Two cases of female urethral reconstruction with acellular porcine urinary bladder matrix

Introduction and hypothesis

Female urethral reconstruction via the traditional routes can be limiting for various reasons. Current literature on the use of acellular biologic grafts derived from viscera for female urethral reconstruction is limited. We present two cases of women with complete loss of their posterior urethra presenting for urethral reconstruction.

Methods

Two cases of urethral reconstruction using acellular porcine urinary bladder matrix (UBM), along with labial fat pad transposition and biologic pubovaginal sling are presented.

Results

In both cases the UBM graft showed successful conversion to what appeared to be normal urethral mucosa. One woman showed significant improvement in continence and the other showed complete continence.

Conclusions

Female urethral reconstruction using acellular porcine UBM is a viable option for patients who have lost a significant portion of their urethra. Both cases demonstrated transition of the graft into the posterior wall of the urethra with significant improvement in continence. Further studies are needed to confirm that acellular porcine UBM can transform to urethral mucosa in women requiring urethral reconstruction.

     

脱细胞猪主动脉基质替代犬食管缺损的实验研究

目的 探讨应用脱细胞猪主动脉基质制备人工食管进行食管替代的可行性。方法应用胰酶、Triton X-100制备脱细胞猪主动脉基质。切除5cm实验犬食管，用两片脱细胞猪主动脉基质缝制成人工食管进行重建，观察存活情况和愈合过程。结果6只实验犬无围手术期死亡，发生吻合口瘘1只，1只在行内镜下扩张治疗时导致新生食管破裂死亡。组织学结果显示术后2周时有疏松结缔组织及大量新生血管形成，4周时大部分人工食管被上皮细胞覆盖。12周时上皮细胞分化至8．10层，有黏膜下腺体结构及肌肉组织。原人工食管已完全吸收，无法用肉眼分辨人工和正常食管。结论猪胸主动脉脱细胞血管基质可作为理想的代食管材料，能较好诱导组织的再生，有较好的应用前景。实验为人工食管的临床应用研究提供了依据。     

Portal blood flow and liver regeneration in auxiliary partial orthotopic liver transplantation in a canine model

Functional competition has been shown to lead to a detrimental outcome in auxiliary liver transplantation. We evaluated the interaction in auxiliary partial orthotopic liver transplantation between the native liver and the graft in terms of portal flow and regeneration. The need for diversion of the portal flow to the graft was also assessed. Reduced-size liver grafts were transplanted orthotopically after partial hepatectomy in beagles. There were two groups: the preserved group, where portal inflow to the native liver was preserved, and the ligated group, where it was interrupted. Portal flow was measured serially and liver regeneration was evaluated on postoperative day 5. Functional competition was not observed in the preserved group. On the other hand, ligation of the native liver portal vein had no obviously detrimental effects on the remnant native liver. This leads to the conclusion that the portal vein to the native liver can be safely ligated to prevent functional competition.     

Different bladder defects reconstructed with bladder acellular matrix grafts in a rabbit model

Objective

To evaluate the potential use of the bladder acellular matrix graft (BAMG), two different bladder defects in the rabbit model were reconstructed.

Materials and methods

Two groups of rabbits underwent partial bladder wall cystectomy (group?A, 30?C40%; group?B, 70?C60%) and reconstruction of the defects with an equally sized BAMG. After 4, 12, and 24?weeks, bladder cystographs were performed. Then the rabbits were killed after uneventful postoperative periods, and the grafts were harvested for H&;E staining and immunohistochemical staining.

Results

Two rabbits died on the postoperative days 3 and 6 in group?A due to urinary peritonitis. At 24?weeks, in group?A, the reconstructed bladders reached a mean volume of 94.39±0.54% of the precystectomy bladder capacity. Histologically, complete regeneration of smooth muscle and urothelium tissue was evident. Regenerated SMCs and urothelium stained positive for ??-smooth muscle actin and AE1/AE3. In group?B, the mean bladder volume was 64.5±3.19% of the precystectomy volume. Histologically, group?B was characterized by multilayered urothelium without organized muscle tissue.

Conclusion

The BAMG was an effective scaffold for bladder wall regeneration in the rabbit model. However, the use of BAMG reconstruction in larger bladder defects did not induce the same quality and quantity of bladder regeneration as the reconstruction of smaller bladder defects.     

复合细胞的膀胱黏膜下层无细胞基质替代长段输尿管的实验研究

目的 评价复合尿路平滑肌细胞和移行上皮细胞的膀胱黏膜下层无细胞基质在大动物体内替代长段输尿管后的结构、功能状况.方法 取长风杂交白猪(不包括在本实验组内)膀胱黏膜下层,洗涤后获得无细胞基质,备用.实验猪10只,切取小块膀胱组织,分离出平滑肌细胞和移行上皮细胞,培养增殖后种植于膀胱黏膜下层无细胞基质,体外共培养.以细胞-无细胞基质复合物替代自体猪一侧中段输尿管,长约5.0～5.5 cm,术后1、2周,1、3、6个月各处死2只,大体观察、组织学和组织浴槽等方法观察替代段输尿管的结构,并进行功能评价.结果 移植替代1个月可见明显肌层形成,3、6个月时已形成良好的移行上皮层和平滑肌层.大体观察见替代段输尿管管腔存在,周围有明显的纤维组织形成.替代段以上输尿管和肾盂扩张.组织浴槽研究显示,替代段输尿管存在平滑肌肌条的一般体外特性.结论 以膀胱黏膜下层无细胞基质作为细胞载体的组织工程输尿管技术在大动物体内替代长段输尿管后,可以获得具有良好组织结构的肌性管道,但其周围的严重纤维化会影响替代段输尿管的功能.     

Collagen I:III ratio in canine heterologous bladder acellular matrix grafts

The objective of this study was to investigate the limitations of a heterologous bladder acellular matrix graft (BAMG) and the influence of the collagen ratio on functional regeneration in a large animal model. Ten female dogs underwent partial cystectomy; eight received BAMG (two homologous; six heterologous) and two partial cystectomy only. A cystometry was performed prior to surgery and 7 months postoperatively when all animals underwent sacral root stimulation. Tissue specimens were studied by histologic and immunohistochemical techniques and for collagen types. At month 7, all animals survived and bladder capacity in the grafted animals was increased. All grafts demonstrated all components of a normal bladder wall. Nerves were seen with the density decreasing with distance from the anastomosis. The BAMG processing and follow-up demonstrated no changes in the homologous tissue, whereas in the heterologous tissue, the amount of collagen changed with the processing during implantation. None of these heterologous specimens demonstrated a similar collagen ratio to the hosts’. The homologous BAMG undergoes more complete regeneration. In the heterologous BAMG, collagen seems not to be replaced. The amounts and ratio of collagen types I and III seem to influence smooth muscle regeneration.     

A canine model of irreversible urethral sphincter insufficiency

OBJECTIVE

To develop a canine model of external urinary sphincter insufficiency by creating irreversible damage to the sphincter, because there is a need for a reliable and reproducible large animal model for the study of stress urinary incontinence (SUI) caused by deficient sphincter function.

MATERIALS AND METHODS

About a quarter of the total external sphincter muscle was removed microsurgically from seven female dogs; three age‐matched dogs served as normal controls. The dogs had standard urodynamic and radiographic studies before and at 1, 2, 3, 4 and 7 months after surgery. Three dogs were killed at 4 months and four at 7 months after surgery for tissue analyses.

RESULTS

The interventions produced a consistent outcome. Urodynamic studies showed a significant and sustained decrease in sphincter function, which included a static urethral pressure profile, stress urethral profile and detrusor leak‐point pressure. Furthermore, in vivo pudendal nerve stimulation and organ‐bath studies of the retrieved tissue strips confirmed the loss of sphincter tissue function. Histologically, absence of functional sphincter muscle was evident in the damaged sphincter region.

CONCLUSIONS

These results show that a reliable and reproducible canine model of irreversible sphincter insufficiency can be created by microsurgical removal of sphincter muscle tissue. This model of external sphincter insufficiency could be used for evaluating methods (e.g. cell therapies) for treating SUI.     

Ventral hernia repair using allogenic acellular dermal matrix in a swine model

Background This study was designed to assess the long-term efficacy of allogenic acellular dermal matrix (ADM) used as an interpositional graft for ventral hernia repair in a swine model.Methods We created 12×4-cm full-thickness abdominal wall defects in 22 Yucatan miniature pigs. The defect was repaired with either two 6×4-cm pieces of AlloDerm (acellular dermal matrix processed from pig skin in order to avoid a xenogenic response, LifeCell Corporation, Branchburg, NJ USA) (n=12), or expanded polytetrafluoroethylene mesh (ePTFE) (Gore-Tex, W.L. Gore & Associates, Inc., Newark, DE USA) (n=10). In six pigs, a separate 3-cm fascial incision was made, which was then suture repaired as a control for tensiometry testing. The surgical sites were evaluated at either 3 months or 9 months for the presence of a hernia, stretching of the implant, adhesions, vascularity, and biomechanical strength.Results Two hernias occurred in both the ADM and the ePTFE groups. There was minimal stretching of the implants and minimal adhesions in both groups. Fluorescein testing and histology indicated vascular ingrowth into the ADM. There was no statistical difference between the mean breaking strengths of the ADM-fascial interface (106.5 N±SD 40.1), the interface between two pieces of ADM (149.1 N±SD 76.7), and the primary fascial repair (108.1 N±SD 20.9) at 9 months. The ADM-fascial interface had a significantly higher breaking strength than that of the ePTFE-fascia interface (66.1 N±SD 30.1) (P=0.017, t-test, P=0.043 Wilcoxon rank sum test).Conclusions In this study, we were unable to demonstrate a difference between ADM and ePTFE in their ability to repair ventral hernias at 9 months in a swine model. The ADM additionally supports vascular ingrowth and exhibits increased breaking strength at the fascia-implant interface.This paper won the Fruchaud prize for best poster presentation at the American Hernia Society meeting in Orlando, Fla., USA, on February 27, 2004.This study was funded in part by an unrestricted donation to the University of Maryland Division of Plastic Surgery research fund from LifeCell Corporation. Dr. Ronald P. Silverman also has received honoraria from LifeCell Corporation as a speaker.     

异种(猪)脱细胞真皮基质一次性包扎治疗深Ⅱ度烧伤

目的探讨应用异种(猪)脱细胞真皮基质一次性包扎治疗深Ⅱ度烧伤创面的临床应用效果。方法1997年1月—2004年1月,应用异种(猪)脱细胞真皮基质一次包扎治疗50%~95%总体表面积(TBSA)、深Ⅱ度烧伤的患者67例[异种(猪)脱细胞真皮基质治疗组];同期保痂治疗的50%~95%TBSA、深Ⅱ度的患者10例(保痂治疗组),观察创面愈合时间和愈合质量及其并发症发生情况。治愈患者经过3个月~2年的随诊,观察瘢痕增生情况。结果异种(猪)脱细胞真皮基质治疗组深Ⅱ度创面中途基本不需换药,创面愈合时间缩短,平均(12.2±2.6)d,而保痂治疗组愈合时间为(27.4±3.5)d,差异具有统计学意义(P<0.05);同时,异种(猪)脱细胞真皮基质治疗组瘢痕增生情况较保痂治疗组明显减轻或者无瘢痕增生。结论一次性覆盖异种(猪)脱细胞真皮基质可有效地治疗深Ⅱ度烧伤创面,能加快创面愈合,减轻瘢痕增生,从而降低烧伤感染和炎症反应综合征的发生。     

自体BMSCs复合改建脱细胞真皮基质体内构建组织工程软骨的实验研究

[目的]目的:探讨BMSCs复合脱细胞真皮基质(ADM)三维多孔支架体内构建组织工程软骨的可行性。[方法]首先对支架材料进行大体及扫描电镜观察,分别测定支架的孔隙直径、孔隙率、降解率;其次,分离培养兔骨髓基质细胞(BMSCs),采用扫描电镜及MTT法检测BMSCs在支架材料上的生长、增殖情况;最后取3个月龄清洁级新西兰大白兔27只,雌性,体质量(2.4±0.2)kg,随机分为3组,即A组:空白对照组(仅髁部造缺损),B组:单纯ADM覆盖,C组:ADM+BMSCs,细胞支架复合物体外培养1周后植入兔股骨髁软骨缺损处,分别在4、8、12周后对标本进行组织学、免疫化学检测及ICRS评分。[结果]测量示支架孔隙直径为(101.2±9.3)um,孔隙率为88.6%±2.7%,降解率2周为(13.83±7.12)%,4周为(25.66±8.19)%。MTT法显示细胞在支架上生长良好,与对照组相比,吸光度值差异无统计学意义(P>0.05),提示支架相容性良好,无细胞毒性。经过最长12周培养后取材进行组织学、免疫化学检测,结果显示ADM+BMSCs组软骨缺损获得了更为满意的修复效果:关节表面平坦光滑,与周围组织未见明显界限;组织学染色证实软骨基质分泌旺盛并有典型软骨细胞形成,组织结构类似正常关节软骨,ADM+BMSCs组术后第4、8、12周ICRS评分均高于其他两组,差异具有统计学意义(P<0.05)。[结论]ADM孔隙均匀,组织相容性好,适于细胞粘附及长期生长,是一种适用于软骨组织工程的良好载体。BMSCs-ADM支架复合体在体内成功构建组织工程软骨,可进一步用于软骨组织工程研究。     

不同种属脱细胞真皮与自体皮复合移植的比较性研究

目的　观察不同种属脱细胞真皮基质 (acellulardermalmatrix,ADM)与自体皮复合移植的效果 ,为异种ADM的临床应用提供理论依据。　方法　本地产白色小猪 6头 ,分为异种 (人 )ADM +自体刃厚皮组 (A组 )、同种异体 (猪 )ADM +自体刃厚皮组 (B组 )、单纯自体刃厚皮组 (C组 )及单纯自体中厚皮组 (D组 )。观察术后 2、4、8、12、2 4周内移植物存活率 ,以及移植皮片收缩程度、移植区组织学变化等情况。　结果　A、B组移植后皮片外观光滑、有弹性 ;两组均获得了满意的皮片成活率 ,并可迅速诱导成纤维细胞、血管内皮细胞等宿主修复细胞的长入 ;两组移植皮片收缩面积有大于C、D组的趋势 (P <0.0 5);术后 2 4周移植区组织与单纯中厚皮移植组织结构一致。　结论　在观察期内(复合移植后 2 4周 ) ,与自体皮复合移植时 ,同、异种ADM具有相近的生物学作用 ,异种来源的ADM可能具有更广阔的应用前景     

Guiding spontaneous tissue regeneration for urethral reconstruction: Long-term studies in the rabbit

We designed long-term in vivo experiments to study rabbit urethral regeneration and remodelling over a hyaluronan biodegradable prosthesis. Seven months after the resection of a 1.5-cm-long tract of the urethra and its substitution with the prosthesis, radiological analysis showed the disappearance of the implant and the re-establishment of urethral continuity along the transmural defect. The regenerated tissue remodelled around the implant and exhibited good distensibility under pressure. Histological evaluation showed that the neo-urethra was lined with transitional epithelium and the stroma contained abundant elastic fibres. An examination of the pattern of the major cytoskeletal and cytocontractile proteins of smooth muscle cells and fibroblasts was able to distinguish fibroblasts from smooth muscle cells and myofibroblasts in the neo-urethra. These experiments provide evidence for the potential, successful use of biocompatible/bioresorbable devices for reconstructive surgery of the urethra. Received: 16 June 1997 / Accepted: 19 September 1997