同种异体半月板联合骨软骨移植的实验研究

目的:探讨新鲜同种异体半月板骨软骨联合移植治疗胫骨平台毁损伤后骨关节炎的疗效。方法:成年新西兰大白兔36只,随机分为A、B、C3组,各12只。A组行右膝内侧半月板连同胫骨平台骨软骨移植,克氏针交叉固定骨块。B组行右膝内侧半月板移植,左膝内侧半月板取出制备新鲜冷冻半月板。C组行左膝内侧新鲜冷冻半月板移植。术后4、8、12周分批取材行大体观察、组织学检查和胫骨平台软骨氨基己糖(GAG)测定。结果:12周时A组移植胫骨平台软骨与B、C组半月板移植术后的内侧胫骨平台软骨氨基己糖含量差异无统计学意义;A、B组移植的半月板纤维软骨细胞数差异无统计学意义;A组半月板移植的纤维软骨细胞数多于C组。结论:新鲜同种异体半月板骨软骨联合移植能修复胫骨平台毁损伤。     

Immediate versus delayed meniscal allograft transplantation in sheep

The aim of the current study was to assess the effect of immediate and delayed transplantation on articular cartilage. Icelandic sheep had surgery on the medial menisci in both knees. The knees were divided into four groups; 16 control knees had sham surgery, 15 knees had meniscectomy, 14 knees had immediate allograft transplantation, and 14 knees had delayed transplantation 3 months after meniscectomy. The two horns of the fresh allograft were fixed with suture anchors through bone tunnels. The sheep had autopsies 6 months after surgery. An additional six knees were examined 3 months after meniscectomy to examine the cartilage before the delayed implantation. Four standardized samples were taken from the medial compartment of the knee for histologic evaluation according to a modification of Mankin's system, where degenerative changes to the articular cartilage were scored semiquantitatively for structure, proteoglycan content, cellularity, and cell cloning. Knees that had meniscectomy and delayed transplantation showed equally high scores in articular cartilage degeneration, and both scored higher than knees that had immediate transplantation, which again scored higher than the control knees. In short-term observations, immediate medial meniscal allograft transplantation reduced but did not prevent degeneration of the articular cartilage. Immediate transplantation was superior to delayed transplantation in preventing cartilage degeneration.     

Architectural remodeling in deep frozen meniscal allografts after total meniscectomy

This study assesses the biological characteristics of cell repopulation and matrix remodeling in deep frozen meniscal allografts after total meniscectomy and allograft transplantation. Thirty-two mature New Zealand White rabbits were operated on, and the allografts were assessed at 12 and 26 weeks postsurgery. Before transplantation, fresh medial menisci were placed into liquid nitrogen to kill all intrinsic cells. Frozen meniscal allografts showed collagen remodeling coincident with revascularization and cellular repopulation. Biochemical characterization showed active collagen remodeling of the allografts at 12 and 26 weeks. In situ hybridization showed that expression of types I and III procollagen mRNAs were increased at 12 weeks, especially near the region of the synovial capsule. At 26 weeks after transplantation, the pattern of collagen-type expression progressed toward normal; that is, type I procollagen mRNA expression was prominent, whereas only a small amount of type III procollagen mRNA was observed. These data indicate the adaptation of the repopulating cells from the host to the frozen allograft at 26 weeks after transplantation.Arthroscopy 1998 Apr;14(3):250-7     

Cellular and humoral immune responses after fresh meniscal allografts in mice

Summary To date, no study of allogeneic meniscal transplantation has investigated both the host cellular immune response and the humoral immune response. Using inbred mice, we examined cellular immunity to meniscal allografts by assaying mixed lymphocyte culture and investigated humoral immunity through a complement-dependent cytotoxity test. The level of the stimulation index of the mixed lymphocyte culture seen after placing fresh meniscal allografts subcutaneously was not significantly higher than when isograft controls were similarly placed. Following placement of the allografts, no specific antibodies were detected in serum throughout the 24-week period after grafting. Thus, in mice, fresh meniscus apparently is not immunogenic. Our results tentatively suggest that a fresh allogeneic meniscus might be transplanted without any special treatment to decrease its immunogenicity.     

Histological studies of intermingled transplantation of autografts and allografts in rabbits

Experimentally induced skin wounds in adult rabbits were covered with intermingled transplantation of autografts and allografts and histological studies were made during the healing process of the wound. The specimens were obtained from the junction between autografts and allografts and midway between the autografts at an interval of 3 days over a period from 6 to 40 days after the transplantation. Examination of the histological specimens showed rejection of the superficial allografts at the beginning of the second week following transplantation. The autoepithelium rapidly grew into the split thus created in the allograft. At about 3 weeks this process was complete with the presence of a flat epithelium covering the entire wound surface.     

Histological analysis of human meniscal allografts. A preliminary report

BACKGROUND: Little is known about the biology of meniscal allograft transplantation in humans. In particular, little information is available about the phenotype of the cells that repopulate the allograft, whether an immune response is elicited against the graft, and whether the repopulating cells synthesize normal extracellular matrix components. METHODS: A small biopsy specimen of the meniscal allograft (twenty-eight menisci in twenty-five patients) and the adjacent synovial membrane (sixteen patients) was harvested during follow-up arthroscopy in patients who had undergone meniscal allograft transplantation at a mean of sixteen months earlier. Seventeen patients had undergone concomitant reconstruction of the anterior cruciate ligament with an allograft. Normal menisci (unimplanted allografts) and synovial specimens from age-matched controls were examined as well. All twenty-eight meniscal allografts were examined histologically. Immunohistochemical analysis was carried out on ten menisci and nine synovial specimens with use of monoclonal antibodies to class-I and class-II major histocompatibility complex antigens, CD-8, CD-11b, and CD-19 epitopes, as well as other epitopes, to demonstrate immunogenic macromolecules, cytotoxic T-lymphocytes, activated macrophages, and B-lymphocytes. RESULTS: Most of the specimens demonstrated incomplete repopulation with viable cells. The repopulating cells stained positively with phenotype markers for both synovial cells and fibroblasts. Polarized light microscopy demonstrated evidence of active remodeling of the matrix. The cells in frozen, unimplanted menisci stained positively for class-I and class-II human leukocyte antigens, indicating immunogenicity at the time of transplantation. Overall, nine of twelve specimens contained immunoreactive cells (B-lymphocytes or cytotoxic T-cells) in the meniscus or synovial tissue. However, only a small number of these cells was present. There was no evidence of frank immunological rejection. The clinical outcome (success or failure of the transplant) was not related to the overall histological score or to the presence of an immune response in the meniscal or synovial biopsy specimen. CONCLUSIONS: Human meniscal allograft transplants are repopulated with cells that appear to be derived from the synovial membrane; these cells appear to actively remodel the matrix. Although there is histological evidence of an immune response directed against the transplant, this response does not appear to affect the clinical outcome. The presence of histocompatibility antigens on the meniscal surface at the time of transplantation (even after freezing) indicates the potential for an immune response against the transplant. CLINICAL RELEVANCE: Despite the absence of frank immunological rejection, a subtle immune reaction may affect the healing, incorporation, and revascularization of the graft. It is possible that the structural remodeling associated with cellular repopulation may render the meniscus more susceptible to injury.     

Changes in energy metabolism of allografts after liver transplantation

To evaluate the function of energy metabolism in allografts after liver transplantation, changes in hepatic energy charge levels, oxidative and phosphorylative activities of mitochondria and arterial blood ketone body ratio (acetoacetate/3-hydroxybutyrate; KBR) were studied in piglets. Hepatic energy charge levels decreased to 0.831 +/- 0.010 at 3 days and 0.836 +/- 0.009 at 3 weeks after operation compared to the preoperative value of 0.868 +/- 0.006 (p less than 0.01), and returned to 0.856 +/- 0.007 at 6 weeks. Mitochondrial oxidative and phosphorylative activities were moderately enhanced to 19.14 +/- 2.07 (10(-10) mol ATP/mg of mitochondrial protein/s) at 3 days and 20.89 +/- 1.72 at 3 weeks compared to the preoperative value of 16.74 +/- 2.36, and returned to 16.65 +/- 1.54 at 6 weeks. There was no significant difference in the concentrations of mitochondrial respiratory components, except in cytochrome c + c1. KBR decreased immediately at the beginning of the anhepatic phase and rapidly recovered to the preoperative level within 60 min after revascularization of allografts. There was no change in KBR during the postoperative course except in cases with clinical deterioration. From these results, it is suggested that the mitochondrial capacity for ATP synthesis was enhanced to compensate for the decreased energy charge level and that a decreased KBR is a sign of a critically deranged metabolic function in allografts.     

Scintigraphic assessment of rabbit knee joints after meniscal allograft transplantation

Purpose: It has been shown that meniscal allografts show capsular ingrowth in meniscectomized knees. However, it remains to be established whether a transplanted meniscus can prevent degenerative changes in the long term. In the present study, scintigraphy was used to evaluate degenerative changes in rabbit knees after meniscectomy only and after meniscectomy followed by immediate or delayed meniscus transplantation. Type of Study: Experimental study. Methods: Twenty-eight rabbits were divided into 4 groups. Three rabbits developed infective arthritis and were excluded from the study. In group A (6 animals), 2 rabbits underwent medial meniscectomy, 3 rabbits underwent transplantation with a freshly harvested medial meniscal allograft immediately after meniscectomy, and 1 rabbit underwent a sham operation. In group B (6 rabbits) medial meniscectomy was performed. Group C (6 rabbits) underwent meniscal transplantation immediately after meniscectomy. Group D (7 rabbits) underwent delayed allograft transplantation at 6 weeks after meniscectomy. The animals in group A underwent scintigraphy at 6 weeks after surgery. In the other groups, scintigraphy was performed at 1-year follow-up. Contour changes of the knee joints and uptake of radiolabeled diphosphonate in the subchondral bone were evaluated. Results: No animals in group A showed any abnormalities scintigraphically. Medial compartment changes in group B were more pronounced than in group C, but this difference was not statistically significant. A significant increase in contour changes of the femoral condyle was seen in group D. Conclusions: Immediate meniscal allograft transplantation did not result in a significant protecting effect on articular cartilage against osteoarthritic degeneration on a long-term basis. Delayed meniscal transplantation revealed even more degenerative changes of articular cartilage than meniscectomy without transplantation.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 5 (May-June), 2003: pp 506–510     

Repair of three-month-old experimental meniscal lesions in rabbits

Repair of three-month-old longitudinal meniscal lesions in the central avascular portion of the knee joint was investigated in 18 rabbits. Three months after a longitudinal incision was made in the avascular portion of the meniscus, no healing was observed. At that time a full-thickness radial cut from the lesion to the joint capsule, without using synovial flaps or implants, was performed in ten of the 18 rabbits. Three months later, nine of the ten menisci had healed mainly with cartilaginous tissue, although the repaired areas were different from the normal fibrocartilage both histologically and at gross inspection. Synovitis with hyperplasia of the lining cells, which was present in all cases at the time of repair, may play an important role in the healing process.     

Pulmonary flow-resistance relationships in allografts after single lung transplantation in dogs

To evaluate the applicability of single lung transplantation as a treatment of pulmonary hypertension, we investigated the relationships between the pulmonary blood flow and resistance in allografts 10 days after single lung transplantation in dogs. In eight surviving recipients and five healthy dogs (control group), pulmonary flow-resistance relationships were investigated at flows in the range of 0.3 to 2.0 L/min at 0.1 L/min increments. Resistance decreased from 2585 to 746 dyne.sec.cm-5 in the successful group (five allografts receiving complete studies) and 2400 to 891 in the control group with an increase of flow. Lung water content of the successful group was 2.0 times that of the control group (successful group, 95.6 +/- 16.7 gm; control group, 47.8 +/- 7.5 gm), and water content of the other allografts (unsuccessful group), including allografts of dogs that died before investigations, was 2.2 times that of the successful group (unsuccessful group, 211.0 +/- 89.6 gm). The chest roentgenograms of the successful group showed mild or moderate consolidations, whereas those of the unsuccessful group showed severe consolidations, but no difference was found in pulmonary flow-resistance relationships between the successful and the control groups. These results show that the allografts, which have about twice the water content of normal lung, maintain adequate pulmonary vascular function. We concluded that single lung transplantation could be an effective treatment for pulmonary hypertension.     

Attitudes of patients before and after transplantation towards various allografts.

BACKGROUND: The presence of an allogeneic graft inside the body may have psychological impact on transplant patients. It was the aim of this study to evaluate the attitude of patients before and after different types of organ transplantation towards organ allografts. METHODS: A total of 1,049 patients (722 patients after and 327 patients on the waiting list for either kidney, liver, heart, or lung transplantation) under care of a single transplant center were studied using a questionnaire with blinded analysis of the data. Mental condition of the patients, their attitude towards the allograft and its donor, emotional stress caused by a graft, and correlation of the attitudes with clinical and demographic parameters were analyzed. RESULTS: The self-reported mental condition of the patients was markedly and consistently better after organ transplantation; 27% of patients before and 60% after transplantation were in good mental condition. Sixty-two percent of transplant patients considered the graft as their own organ, 37% regarded it as a foreign organ now belonging to their body, and 1% considered it as a foreign body; among waiting list patients, 40%, 55%, and 5% assumed they would perceive their graft accordingly. The graft caused considerable emotional stress for 2% of transplant patients, whereas for 70% it did not cause any stress; the latter was assumed by 47% of patients before transplantation. Eleven percent of transplant patients frequently think about the origin of their graft, and 30% would like to have information about their donor. Knowledge about different religion, opposite sex, homosexuality, suicidal death, and age above 65 years of their donor would be of moderate or major concern for 0%, 3%, 21%, 24%, and 38% of the patients, respectively. CONCLUSIONS: The comprehensive survey shows that transplant patients incorporate their graft well into their body image. Emotional stress caused by the graft is very low and is generally less than assumed before transplantation. Knowledge about certain characteristics of the donor may cause increased concerns in some patients.     

同种异体半月板移植术临床效果的初步分析

目的探讨关节镜下异体半月板移植的手术适应证、康复训练计划和免疫反应等问题。方法建立国人异体半月板组织库，对12例半月板损伤后切除半月板的患者，在关节镜下实施异体半月板移植微创手术，制定康复计划，观查其临床效果，结合文献讨论异体半月板移植术的围手术期相关问题。结果本组患者均无手术副损伤，早期关节轻度肿胀，无伤口渗液。术后2周，伤口愈合良好。术后6周，关节肿胀基本消失。随访6—17个月（平均10．3个月），患者行走功能正常，膝关节活动度均值与术前比较差异无统计学意义。膝关节疼痛评分（VAS）术后明显低于术前（P〈0．01）。Lysholm评分术后明显提高（P〈0．05）。术后各项免疫学指标均在正常范围。MRI示移植半月板位置良好，固定可靠。1例患者术后12周关节镜检查，见移植半月板形态正常，与关节囊愈合良好。结论鉴于目前对半月板切除术后（半月板缺损）的并发症治疗存在很大困难，异体半月板移植可能成为一项重要的临床治疗技术。异体半月板移植可获得较好的近期临床效果，临床未见明显的免疫排斥反应。但有关异体半月板移植手术适应证、康复训练及远期效果等围手术期的相关问题还需更深入的探讨。     

Prediction of delayed graft function after renal transplantation

Introduction:

Delayed graft function (DGF), defined as the need for dialysis during the first week after renal transplantation, is an important adverse clinical outcome. A previous model relied on 16 variables to quantify the risk of DGF, thereby undermining its clinical usefulness. We explored the possibility of developing a simpler, equally accurate and more user-friendly paradigm for renal transplant recipients from deceased donors.

Methods:

Logistic regression analyses addressed the occurrence of DGF in 532 renal transplant recipients from deceased donors. Predictors consisted of recipient age, gender, race, weight, number of HLA-A, HLA-B and HLA-DR mismatches, maximum and last titre of panel reactive antibodies, donor age and cold ischemia time. Accuracy was quantified with the area under the curve. Two hundred bootstrap resamples were used for internal validation.

Results:

Delayed graft function occurred in 103 patients (19.4%). Recipient weight (p < 0.001), panel of reactive antibodies (p < 0.001), donor age (p < 0.001), cold ischemia time (p = 0.005) and HLA-DR mismatches (p = 0.05) represented independent predictors. The multivariable nomogram relying on 6 predictors was 74.3% accurate in predicting the probability of DGF.

Conclusion:

Our simple and user-friendly model requires 6 variables and is at least equally accurate (74%) to the previous nomogram (71%). We demonstrate that DGF can be accurately predicted in different populations with this new model.     

Comparison of muscle force after immediate and delayed reinnervation using nerve-muscle-endplate band grafting

BackgroundBecause of poor functional outcomes of currently used reinnervation methods, we developed novel treatment strategy for the restoration of paralyzed muscles—the nerve-muscle-endplate band grafting (NMEG) technique. The graft was obtained from the sternohyoid muscle (donor) and implanted into the ipsilateral paralyzed sternomastoid (SM) muscle (recipient).MethodsRats were subjected to immediate or delayed (1 or 3 mo) reinnervation of the experimentally paralyzed SM muscles using the NMEG technique or the conventionally used nerve end-to-end anastomosis. The SM muscle at the opposite side served as a normal control.ResultsNMEG produced better recovery of muscle force as compared with end-to-end anastomosis. A larger force produced by NMEG was most evident for small stimulation currents.ConclusionsThe NMEG technique holds great potential for successful muscle reinnervation. We hypothesize that even better muscle reinnervation and functional recovery could be achieved with further improvement of the environment that favors axon-end plate connections and accelerates axonal growth and sprouting.     

Glutaraldehyde-cross-linked meniscal allografts: clinical, gross, and histological results

Osteoarthritic changes in the knee are often a late result of total meniscectomy. In cases of total resection, availability of a prosthetic meniscus might limit development of these changes. The objective of this research was to evaluate a glutaraldehyde-cross-linked medial meniscus as a morphologically and biologically compatible prosthesis in a canine model. Medial and lateral menisci were harvested from donor dogs, frozen in saline, and cross-linked with glutaraldehyde. Five host animals were selected and matched with donors. Glutaraldehyde-cross-linked medial menisci were implanted bilaterally in the stifle joints and one glutaraldehyde cross-linked lateral meniscus was implanted subcutaneously. Clinical results showed asymptomatic limb and joint usage during the 12 postoperative weeks. Gross and histological evaluations indicated acceptable biocompatibility. The subcutaneous implants were encapsulated with a thin fibrous tissue capsule that was only mildly inflamed. Within the joints, the anterior attachment and periphery were maintained in position by their sutures; however, there was dehiscence of the posterior suture in all cases. The articulating surfaces of the implants were intact. There was an initial loss in the quantity of proteoglycans following glutaraldehyde treatment, with significant recovery after implantation into the joints. There were significant degenerative changes (loss of proteoglycans and fibrillation) in the articular cartilage on the femoral condyle and tibial plateau most likely a result of the posterior attachment failure. It was concluded that glutaraldehyde-cross-linked meniscal allografts showed an acceptable degree of histocompatibility. However, failure of the posterior attachment interfered with testing the efficacy of the prosthesis.(ABSTRACT TRUNCATED AT 250 WORDS)