Reinnervation of syngeneic pancreatico-duodenal grafts in rats

BACKGROUND: Knowledge on the reinnervation of transplanted organs is scarce, and the aim of the study was therefore to evaluate to what degree syngeneic pancreas grafts were reinnervated in rats. METHODS: Syngeneic pancreatico-duodenal transplantations were performed in normoglycemic Wistar-Furth rats. Native and transplanted pancreas and duodenum were removed 4 or 40 weeks after implantation, and processed for indirect immunofluorescence using antibodies directed against vasoactive intestinal peptide, substance P (SP), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), tyrosine hydroxylase (TH), or the general neuronal marker protein gene product 9.5. RESULTS: Four weeks after transplantation a moderate to rich number of protein gene product 9.5-positive nerve fibers were found homogeneously distributed through the pancreas, probably representing the intrapancreatic nervous system, because the grafted pancreas lacked both a sympathetic (TH/NPY) and sensory (SP/CGRP) innervation 4 weeks after implantation. In a few of the animals there was a marked increase in SP-immunoreactive nerves (lacking CGRP), most conspicuous in the duodenal portion, both 4 and 40 weeks after transplantation probably secondary to a chronic pancreatitis. The fibers seemed to emanate from intrapancreatic ganglia and possibly also from enteric neurons in adjacent parts of the duodenum. A few scattered vasoactive intestinal peptide-containing nerve fibers probably also emanating from local ganglia could be seen throughout the grafted pancreas both 4 and 40 weeks after transplantation. At 40 weeks after transplantation sympathetic (TH- and NPY-positive) nerve fibers were regularly seen, whereas CGRP-positive nerve fibers were still virtually lacking in the pancreas. To trace the origin of the ingrowing nerve fibers, the tracer True Blue was injected into the grafted pancreas of some rats 38 weeks after transplantation, i.e., 2 weeks before killing. True Blue-labeled nerve cell bodies were numerous in the celiac ganglion (presumably sympathetic nerves) and few in dorsal root ganglia (sensory nerves). CONCLUSIONS: The data suggest that the transplanted rat pancreas becomes reinnervated by mainly sympathetic nerve fibers.     

Differential dissection of the rat E16 ventral mesencephalon and survival and reinnervation of the 6-OHDA-lesioned striatum by a subset of aldehyde dehydrogenase-positive TH neurons

The retinoic acid-generating enzyme, aldehyde dehydrogenase (AHD), is expressed in a subpopulation of dopaminergic neurons found in the substantia nigra. Using AHD and tyrosine hydroxylase (TH) as immunohistochemical markers, we determined whether differential dissection of the embryonic (E16) ventral mesencephalon (VM) into its lateral and medial portions contributed equally to the number of TH cells surviving transplantation, if grafted AHD/TH neurons reinnervate the host striatum according to their normal projection patterns, and examined the functional recovery caused by the implanted cells as assessed by amphetamine-induced rotation in a 6-OHDA-lesioned model of Parkinson's disease. The embryonic tissue was transplanted as solid pieces injected via a 20-gauge lumbar puncture needle into the center of the deafferented striatum. Groups received either one complete ventral mesencephalic piece (VM), two medial pieces of ventral mesencephalic tissue (MVM), or two lateral pieces of ventral mesencephalic tissue (LVM). Both VM and MVM groups showed a significant decrease in amphetamine-induced rotation over time and, there was no difference in the degree of reduction observed between the two groups. Histological evaluation of the transplants revealed a much larger total number of surviving TH cells in grafts from the VM and MVM groups compared to the LVM group. Surviving AHD/TH neurons were found in all groups. Whereas TH staining of the transplanted striatum displayed a halo of graft-derived fibers all around the transplant and integration of these fibers into the host neuropil, AHD staining showed a preferential reinnervation of the dorsolateral striatum corresponding to the normal projection pattern of AHD/TH neurons. In summary, selective dissection of the embryonic ventral mesencephalon is possible, functional recovery as assessed by amphetamineinduced rotation in animals transplanted with MVM is similar to that seen in animals grafted with VM, and AHD/TH neurons have a selective reinnervation pattern in the PD transplantation paradigm. These findings may have implications for the grafting of fetal mesencephalic tissue in PD patients.     

Reinnervation after nerve suture in rat groin flaps

Regeneration of sensory and adrenergic nerves in the skin was studied in rats. The aim was to investigate the effect of reanastomosing the cut nerve ends of the nerve trunk leading to the microvascular groin flap. Reinnervation was demonstrated immunohistochemically using calcitonin gene-related peptide (CGRP) as marker for sensory nerves, neuropeptide Y (NPY) and tyrosine hydroxylase (TH) as markers for adrenergic nerves and Protein Gene Product 9.5 (PGP 9.5) as general neuronal marker. It was demonstrated that reanastomosing of the nerve trunk was favourable for both the sensory and sympathetic reinnervation of microsurgical flaps. © 1998 Wiley-Liss, Inc. MICROSURGERY 18:1–5, 1998.     

Tissue transplants in primates for upper extremity reconstruction: a preliminary report

Recent advances in clinical transplantation surgery suggest that hand transplantation is no longer an unrealistic expectation. However, two questions must be answered. Can composite tissue transplants survive in a primate species? Does the required neural reinnervation occur under immunosuppression? Four hand transplants and seven neurovascular free flap transplants were done in baboons immunosuppressed with Cyclosporin A and steroids (methylprednisolone). Long-term survival occurred in nine. Electrophysiologic tests of sensory axons revealed reinnervation of transplanted skin as evidenced by well-defined, low threshold receptive fields in the donor tissue. Reinnervation of donor muscle was demonstrated by motor unit recruitment in stepwise fashion after electrical stimulation of the recipient's median and ulnar nerves. Afferent fibers serving the donor's joints and muscle spindles were also observed.     

Experimental pancreatic allotransplantation in large animals. The role of donor kidney and cyclosporine in modifying rejection

Experiments were carried out in outbred dogs and pigs to evaluate the relative immunogenicity of pancreatic islets and segmental pancreas grafts, and whether these could be ameliorated by transplanting a kidney simultaneously from the same donor animal. Various immunosuppressive regimens were also studied. Pancreatic islet allografts never normalized blood glucose in totally pancreatectomized recipients despite the use of cyclosporine (CsA) in high doses (40 mg/kg/day) and the simultaneous transplantation of a kidney from the same donor. These grafts which never "took" contrast sharply with the experience of pancreatic islet autografts prepared in the same way and inoculated into the spleen, which in all nine instances normalized blood glucose in pancreatectomized recipients. Segmental transplants were performed in swine with duct drainage into the jejunum. Totally pancreatectomized pigs died at 7.8 +/- 1.0 days. In recipients suppressed with low-dose azathioprine (Az) and prednisone (Pred) pancreas grafts alone were rejected in 12.9 +/- 10 days. Synchronous pancreas and kidney transplants treated similarly extended the mean survival of pancreatic grafts to 20 +/- 10 days--which, however, was not significant (P less than 0.1 greater than 0.05). Mean survival time of pancreatic grafts in recipients receiving CsA at 20 mg/kg/day and prednisone 1 mg/kg/day was 14 +/- 6.3 days. The combination of CsA 20 mg/kg/day, Az 2 mg/kg/day, and Pred 1 mg/kg/day prolonged the mean survival time to 39.8 +/- 22 days. These results allow us to conclude that: crude preparations of islet tissue invariably capable of normalizing blood sugar at day 4 when used as autografts failed to "take" despite the existence of alternative sources of antigen present in a well vascularized kidney from the same donor, and despite very high dosages of CsA; triple immunosuppressive therapy had synergistic effects on pancreatic allograft survival; and simultaneous transplantation of kidney and pancreas had little effect on survival times of the pancreas or the kidney.     

Enhanced survival of dopaminergic neuronal transplants in hemiparkinsonian rats by the p53 inactivator PFT-α

A key limiting factor impacting the success of cell transplantation for Parkinson's disease is the survival of the grafted cells, which are often short lived. The focus of this study was to examine a novel strategy to optimize the survival of exogenous fetal ventromesencephalic (VM) grafts by treatment with the p53 inhibitor, pifithrin-α (PFT-α), to improve the biological outcome of parkinsonian animals. Adult male Sprague-Dawley rats were given 6-hydroxydopamine into the left medial forebrain bundle to induce a hemiparkinsonian state. At 7 weeks after lesioning, animals were grafted with fetal VM or cortical tissue into the lesioned striatum and, thereafter, received daily PFT-α or vehicle injections for 5 days. Apomorphine-induced rotational behavior was examined at 2, 6, 9, and 12 weeks after grafting. Analysis of TUNEL or tyrosine hydroxylase (TH) immunostaining was undertaken at 5 days or 4 months after grafting. The transplantation of fetal VM tissue into the lesioned striatum reduced rotational behavior. A further reduction in rotation was apparent in animals receiving PFT-α and VM transplants. By contrast, no significant reduction in rotation was evident in animals receiving cortical grafts or cortical grafts + PFT-α. PFT-α treatment reduced TUNEL labeling and increased TH(+) cell and fiber density in the VM transplants. In conclusion, our data indicate that early postgrafting treatment with PFT-α enhances the survival of dopamine cell transplants and augments behavioral recovery in parkinsonian animals.     

Noradrenergic and cholinergic reinnervation of islet grafts in diabetic rats

Grafted islets become denervated due to the islet transplantation procedure. The aim of the present study was 1) to examine whether islet grafts in the liver, the spleen, and under the kidney capsule in rats become reinnervated following the transplantation and experimental procedures used in our laboratory, 2) whether there is any difference in reinnervation at these different sites, and 3) how these results relate to previous physiological experiments. Isogeneic isolated islets were transplanted into diabetic Albino Oxford rats, resulting in normoglycaemia. After at least 5 wk, graft-receiving organs were removed and several antibodies were employed to detect insulin, neuronspecific proteins, and cholinergic and noradrenergic nerve fibers. Islets in all three receiving organs contained viable insulin-positive B-cells. Neuron-specific enolase (NSE) as well as the growth-associated protein B-50 was observed at all sites. The cholinergic marker choline acetyltransferase (ChAT) was localized in islets grafts at all sites, but with the lowest density in the spleen. Staining for the noradrenergic markers tyrosine hydroxylase (TH) and dopamine-phydroxylase (DBH) was observed in islet grafts at all sites with the lowest density in grafts under the kidney capsule. All these neurochemical substances were most frequently observed in fibers associated with blood vessels, which may be the route along which nerves grow into the graft. It can be concluded that 1) islet grafts in the liver, in the spleen and under the kidney capsule become reinnervated; 2) the innervation pattern of the islet grafts differs only slightly from that in the control pancreatic islets; and 3) in combination with our previously physiological data, we can conclude that these nerve fibers are, at least partly, functionally active.     

Complications in circulation hamper the reinnervation of rat groin flaps

The reinnervation of rat groin island flaps and microneurovascular flaps was investigated. The nerve trunk leading to the flap was transsected in all rats and the nerve ends were either resutured or ligated. Sensory and adrenergic reinnervation of the flaps was studied semiquantitatively after 20 weeks using specific antisera for calcitonin gene-related peptide (CGRP) as a marker for sensory nerves, neuropeptide Y (NPY) for adrenergic nerves and Protein Gene Product 9.5 (PGP 9.5) as a general neuronal marker. The reinnervation of island groin flaps was compared to that in corresponding microneurovascular flaps. The nerve suture clearly increased both sensory and adrenergic reinnervation. In island flaps the reinnervation was good throughout the flap, whereas in microsurgical flaps the reinnervation pattern was more sparse and patchier. Evidently the cause for this was circulatory disorders and the reperfusion injury which takes place after the ischemic period in microsurgical flaps. Received: 3 March 1997 / Accepted: 14 January 1998     

Xenografts of MHC-deficient mouse embryonic mesencephalon improve behavioral recovery in hemiparkinsonian rats

The limited availability of human embryonic tissue for dopamine cell transplants in Parkinson's patients has led to an increased interest in using xenogeneic donor tissue. Unfortunately, without aggressive immunosuppression, such brain xenografts are rejected by the host immune system. Chronic brain xenograft rejection is largely mediated by helper T cells, which require presentation of xenoantigens by major histocompatability complex (MHC) class II for their activation. We examined survival and function of xenografts of E13 mouse mesencephalon deficient in either MHC class I, class II, or both after transplantation into adult hemiparkinsonian rats without immunosuppression. Recipients received grafts from C57BL/6 mice that were either: 1) wild-type (wt), 2) MHC class I knockout (KO), 3) MHC class II KO, 4) MHC class I and II double KO, or 5) saline sham transplants. At 6 weeks after transplantation, recipients of MHC class I KO, class II KO, and double KO xenografts significantly reduced methamphetamine-induced circling rate while rats with wt xenografts and sham-operated rats showed no improvement. MHC class II KO grafts had the greatest number of surviving dopamine neurons. All transplants, including saline sham controls, contained infiltrating host MHC class II-positive cells. Saline sham grafts and MHC class II KO xenografts contained significantly fewer infiltrating host MHC class II-positive cells than did wt grafts. Our results show that MHC class II-deficient xenografts survive transplantation for at least 6 weeks in the absence of immunosuppression, reduce rotational asymmetry, and provoke lesser immune reaction than wt grafts.     

Innervation of syngeneic vein grafts in the rat. The regeneration of adrenergic nerves

Regeneration of adrenergic nerves was studied sequentially in segments of the supradiaphragmatic inferior vena cava transplanted from one rat into the abdominal aorta of another of the same inbred strain. Nontransplanted vein segments were examined as controls. The adrenergic nerves were demonstrated by using the glyoxylic acid-induced fluorescence method and the formaldehyde-induced fluorescence method for the demonstration of cathecholamines. A total of 16 syngeneic grafts were examined 3, 5, 8, 16, 27, and 32 weeks after transplantation. Three additional grafts were wrapped inside a silicone tube during the operation to prevent regeneration of nerves from the surroundings. These rats were then killed 8 weeks after the operation. In the control specimens the supradiaphragmatic inferior vena cava was innervated with a rather dense plexus of adrenergic nerves showing varicosities. No nerves were seen in the 3-week-old grafts. In the 5-week-old grafts some sparsely distributed solitary nerve fibres were seen. In the 8-week-old grafts sparsely distributed regenerated nerves reinnervating the vasa vasorum and nerve plexa were observed. The 16-, 27-, and 32-week-old grafts showed rather poorly innervated areas and areas where the nerve plexus was dense. One graft showed very dense reinnervation with morphologically abnormal adrenergic nerves forming “droplet fibers” and showing dense accumulations of catecholamines. The grafts surrounded with silicone tubes had no adrenergic nerves and showed only some regenerated nerves crossing the suture line. The results of the present study indicated that syngeneic inferior vena cava transplanted into the abdominal aorta will be reinnervated with adrenergic nerves. The pattern of the nerve regeneration remains incomplete and patchy.     

Survival of nigral grafts within the striatum of marmosets with 6-OHDA lesions depends critically on donor embryo age

The study examined the importance of embryonic donor age for the survival of nigral grafts in 6-OHDA-lesioned marmosets. The issue as to whether donor age is critical for the survival of nigral grafts in primates is controversial, because several early reports suggested that relatively old tissue could survive transplantation and produce functional benefits in monkeys, in contrast to the restrictive time dependence observed in rodents. Embryonic marmoset donors embryos of three different ages were employed: 1) E74 (Carnegie stage 18–19); 2) E83–84 (Carnegie stage 23+); 3) E92–93 (foetal period). The nigral neurons derived from the ventral mesencephalon in the two older donor age groups did not survive well when grafted to the striatum of adult marmosets with unilateral 6-OHDA lesions. Although a few tyrosine hydroxylase (TH+) neurons could be identified by immunohistochemistry at graft sites in all recipients in older donor age groups, the numbers of surviving neurons in these were small, on average typically less than 100 TH+ cells. These small grafts were not sufficient to affect amphetamine-induced rotation. In contrast, many more TH+ cells typically survived transplantation in the recipients of graft tissue derived from the youngest donors and amphetamine-induced rotation was significantly reduced in this group alone. The time course and extent of the reduction in rotation was remarkably similar to that observed in previous marmoset nigral graft studies, confirming the utility of amphetamine-induced rotation as a sensitive and reliable indicator of nigral graft function in this species. Considering these results and other recent evidence from monkey to monkey, human to rat, and human to human graft studies, the survival of embryonic nigral tissues derived from primate donors transplanted into the striatum does appear to be critically dependent on the age of the donor tissue.     

Comparison of embryonic stem cell-derived dopamine neuron grafts and fetal ventral mesencephalic tissue grafts: morphology and function

In this study we compared the function and morphology of two types of neural grafts: allografts of fetal ventral mesencephalic (VM) tissue and xenografts of embryonic stem cell (ESC)-derived dopamine neurons. Mouse embryonic stem cells were cultured and exposed to differentiation factors that induced approximately 10% of the cells to express a dopaminergic phenotype. These cells were then harvested and implanted into the denervated striatum of rats with unilateral lesions of the nigrostriatal pathway. Another group of lesioned rats received allografts of fetal ventral mesencephalic tissue. While both types of grafts yield a similar number of tyrosine hydroxylase (TH)-positive cells, amphetamine-induced rotational behavior was differentially affected by these grafts: rotational behavior was significantly reduced in lesioned rats receiving allografts of fetal VM tissue while ESC grafts had slight but insignificant effects on rotational scores. Densitometry measures of TH+ fiber outgrowth revealed a similar area of reinnervation and a comparable number of TH+ cells for ESC graft when compared with VM grafts. These data suggest there are similarities and also distinct differences in the manner in which ESC and VM grafts interact with the denervated striatum.     

Kidney Cografts Enhance Fiber Outgrowth From Ventral Mesencephalic Grafts to the 6-OHDA–Lesioned Striatum,and Improve Behavioral Recovery

Recent studies have demonstrated the presence of many different neurotrophic factors in the developing and adult kidney. Due to its production of this mixture of neurotrophic factors, we wanted to investigate whether fetal kidney tissue could be beneficial for neuritic fiber growth and/or cell survival in intracranial transplants of fetal ventral mesencephalic tissue (VM). A retrograde lesion of nigral dopaminergic neurons was performed in adult Fischer 344 male rats by injecting 6-hydroxydopamine into the medial forebain. The animals were monitored for spontaneous locomotor activity in addition to apomorphine-induced rotations once a week. Four weeks following the lesion, animals were anesthetized and embryonic day 14 VM tissue from rat fetuses was implanted stereotaxically into the dorsal striatum. One group of animals received a cograft of kidney tissue from the same embryos in the same needle track. The animals were then monitored behaviorally for an additional 4 months. There was a significant improvement in both spontaneous locomotor activity (distance traveled) and apomorphine-induced rotations with both single VM grafts and VM–kidney cografts, with the VM–kidney double grafts enhancing the motor behaviors to a significantly greater degree. Tyrosine hydroxylase (TH) immunohistochemistry and image analysis revealed a significantly denser innervation of the host striatum from the VM–kidney cografts than from the single VM grafts. TH-positive neurons were also significantly larger in the cografts compared to the single VM grafts. In addition to the dense TH-immunoreactive innervation, the kidney portion of cografts contained a rich cholinergic innervation, as evidenced from antibodies against choline acetyltransferase (ChAT). The striatal cholinergic cell bodies surrounding the VM–kidney cografts were enlarged and had a slightly higher staining density for ChAT. Taken together, these data support the hypothesis that neurotrophic factors secreted from fetal kidney grafts stimulated both TH-positive neurons in the VM cografts and cholinergic neurons in the host striatum. Thus, these factors may be combined for treatment of degenerative diseases involving both dopaminergic and cholinergic neurons.     

The influence of donor age, nerve growth factor, and cografting with drosophila cells on survival of peripherally grafted embryonic or fetal rat dorsal root ganglia

Previous studies have shown that embryonic rat and human dorsal root ganglion (DRG) cells survive grafting to the cavity of extirpated adult rat DRG. Furthermore, grafted human embryonic neurons were shown to send axons peripherally and into the spinal cord, where they establish functional synaptic connections. This study analyzed the survival of orthotopically allografted rat DRG cells from embryonic stages 15 (E15) and 20 (E20), and the influence on their survival of nerve growth factor (NGF). NGF was delivered to the DRG transplants either by pump infusion or by cotransplantation of cells from Drosophila melanogaster, transgenic for human NGF. Lumbar DRGs of adult rats were removed and a collection of E15 or E20 DRGs placed in the cavity. One month after grafting the total number of DRG cells in the grafts was counted. Differentiation of subpopulations of DRG cells was estimated by counting cells immunostained for calcitonin gene-related peptide (CGRP), Griffonia simplicifolia agglutinin isolectin B4 (GSA), or heavy neurofilament protein (antibody RT97). The results show: i) similar survival of E15 and E20 grafts, with great variability in the survival of different subpopulations in E15 transplants, but a more consistent distribution of different phenotypes in E20 transplants; ii) infusion of NGF for 2 weeks increases the survival of E15 transplants, but has a negative effect on E20 transplants; iii) Drosophila cells transfected with human NGF gene survive peripheral xenografting and have a positive effect on the survival of the GSA- and CGRP-positive populations in E15 and E20 transplants; iv) Drosophila cells without the human NGF gene increase cell survival in E20 transplants. These data suggest that i) the effect of NGF is dependent on the embryonic stage of the transplants, ii) age-dependent sensitivity to NGF influences graft survival, and iii) transgenic Drosophila cells can be cotransplanted with embryonic neural tissue to the mammalian peripheral nervous system with a positive effect on the survival of neural grafts.     

Increased survival of dopaminergic neurons in striatal grafts of fetal ventral mesencephalic cells exposed to neurotrophin-3 or glial cell line-derived neurotrophic factor

The transplantation of fetal mesencephalic cell suspensions into the brain striatal system is an emerging treatment for Parkinson's disease. However, one objection to this procedure is the relatively poor survival of implanted cells. The ability of neurotrophic factors to regulate developmental neuron survival and differentiation suggests they could be used to enhance the success of cerebral grafts. We studied the effects of neurotrophin-3 (NT-3) or glial cell line-derived neurotrophic factor (GDNF) on the survival of dopaminergic neurons from rat fetal ventral mesencephalic cells (FMCs) implanted into the rat striatum. Two conditions were tested: (a) incubation of FMCs in media containing NT-3 and GDNF, prior to grafting, and (b) co-grafting of FMCs with cells engineered to overexpress high levels of NT-3 or GDNF. One week after grafting into the rat striatum, the survival of TH+ neurons was significantly increased by pretreatment of ventral mesencephalic cells with NT-3 or GDNF. Similarly, co-graft of ventral mesencephalic cells with NT-3- or GDNF-overexpressing cells, but not the mock-transfected control cell line, increased the survival of graft-derived dopaminergic neurons. Interestingly, we also found that co-grafting of GDNF-overexpressing cells was less effective than NT-3 at improving the survival of fetal dopaminergic neurons in the grafts, and that only GDNF induced intense TH immunostaining in fibers and nerve endings of the host tissue surrounding the implant. Thus, our results suggest that NT-3, by strongly enhancing survival, and GDNF, by promoting both survival and sprouting, may improve the efficiency of fetal transplants in the treatment of Parkinson's disease.     

与大鼠胰岛细胞联合移植的骨髓间充质干细胞的免疫调节作用

目的 研究同种异体或自体的大鼠骨髓间充质干细胞(MSC)与胰岛肝内联合移植对胰岛移植物的免疫调节作用及其机制.方法 以链佐星制备Lewis大鼠的糖尿病模型,作为胰岛移植受者,分为3组:单纯移植组大鼠经门静脉单独移植SD大鼠胰岛6000 IEQ/kg;同系MSC组大鼠经门静脉共同移植1×109/L的Lewis大鼠MSC 1 ml与SD大鼠胰岛6000 IEQ/kg;同种MSC组大鼠经门静脉共同移植1×109/L的SD大鼠MSC 1 ml与SD大鼠胰岛6000 IEQ/kg.检测受鼠的血糖变化,术后1、3 d大鼠外周血γ干扰素(IFN-γ)、白细胞介素(IL)-2、IL-4和IL-10的含量.结果 3组大鼠术后第1天血糖均下降到13.9 mmol/L以下.同系MSC组移植物存活时间为(11.38±4.03)d,同种MSC组为(5.50±2.07)d,单纯移植组为(2.88±1.25)d(P＜0.01).术后1、3 d,单纯移植组IFN-γ和IL-2的含量显著高于同系MSC组和同种MSC组(P＜0.01),同种MSC组IFN-γ和IL-2的含量高于同系MSC组(P＜0.05);单纯移植组IL-10的含量低于同系MSC组和同种MSC组(P＜0.01),同系MSC组IL-10的含量与司种MSC组相比较,差异无统计学意义(P＞0.05);各组IL-4含量的差异无统计学意义(P＞0.05).结论 MSC与同种胰岛共移植可以延长胰岛移植物存活时间,应用同系MSC的效果优于同种异体MSC.共移植的MSC主要通过减少TH1类细胞因子(IFN-y和IL-2)的表达使受者TH1/TH2平衡向TH2方向偏移.

Abstract：

Objective To compare the immune regulation of syngenic and allogenic mesenchymal stem cells (MSCs) in the transplantation combined with islets. Methods After induction of diabetes in 30 Lewis rats with streptozotocin (STZ), the recipient Lewis rats received islets from SD rats combined with syngenic (group B) or allogenic (group C) MSCs injection via the portal vein. The group of islets transplanted alone served as control (group A). The survival time of grafts in all groups was assessed by the level of blood glucose. ELISA was used to detect the levels of interferon-γ (IFN-γ), interleukin 2 (IL-2), IL-4 and IL-10 in the peripheral blood on the 1st and 3rd day after transplantation. Results The blood glucose levels in all three groups were decreased in a normal range (13. 9 mmol/L) and the survival time of grafts in group B (11.38 ± 4. 03 days) was significantly longer than in group C (5. 50± 2. 07 days) as well as group A (2. 88 ± 1.25 days). On the 1 st and 3rd day after transplantation, the levels of TH 1 cytokines IFN-γ and IL-2 in group A were significantly higher than in groups C and B (P＜0.05). Meanwhile the levels of TH 2 cytokine IL-10were increased in group B, but there was no significant difference between groups A and C (P＞0.05). The levels of IL-4 had no significant difference among these three groups (P ＞ 0.05).Conclusion Islet transplantation combined with MSCs could prolong the survival time of grafts.Syngenic MSCs, superior to allogenic ones, were more effective in changing the balance of TH1/TH2to TH2. Decreased expression of TH1 cytokine (IFN-γ, IL-2), which was closely related to the induction of immune tolerance, was beneficial to the long-term survival of grafts.     

Radiation-Induced Changes in Neuropeptides in the Rat Urinary Bladder

Purpose

To determine whether there was a change in innervation in the rat urinary bladder following x-ray irradiation.

Materials and Methods

The urinary bladders were obtained from rats irradiated 6 months previously with single doses of 15 Gy and 25 Gy x-radiation, and from nonirradiated (control) animals. They were examined immunohistochemically to localize neuropeptide Y (NPY), substance P (SP), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), met-enkephalin (m-ENK), leu-enkephalin (l-ENK), somatostatin (SOM) and the enzyme, tyrosine-hydroxylase (TH). Computer assisted image analysis was used to assess the density of immunoreactive nerve fibres.

Results

The greatest density of nerves observed in the bladder from control animals contained NPY, followed (in decreasing order) by CGRP, VIP, SP and TH. The nerves appeared to run predominantly along the longitudinal axis of the circular and longitudinal muscle fibres. SP-, CGRP-, TH- and occasionally VIP-immunoreactive nerves were observed in the lamina propria, at the base of the urothelium. Perivascular nerves containing neuropeptides and TH were observed throughout the bladder wall.There was an absence of m-ENK-, l-ENK- and SOM-immunoreactive nerves in the control and irradiated rat urinary bladders.In the rat urinary bladder irradiated with 25 Gy x-radiation, there was a significant increase (P less than 0.05) in the density of NPY-, TH- and SP- but not CGRP- and VIP-immunoreactive nerves. There were regional differences within the bladder, that is, there was an increase in VIP-, CGRP- and SP-immunoreactive nerves around and within the urothelium. NPY-immunoreactive nerves were seen in the connective tissue and elastic fibres of the lamina propria for the first time. An increase in the density or fluorescence intensity of perivascular TH- but not neuropeptide-containing nerves was observed.

Conclusion

The increase in the density of NPY-, SP- and TH-immunoreactive nerves in the irradiated bladders may be due to axonal sprouting which contributes to the symptoms of radiation injury.     

Experience with 49 segmental pancreas transplants in 45 diabetic patients

Forty-nine pancreas transplants were performed in 45 patients between July 23, 1978 and May 14, 1982, 18 from related donors. Currently (June 1982), 13 patients have functioning grafts and are insulin independent between 1 and 46 months after transplantation, 5 for more than 1 year. Nineteen patients lost graft function between 1 and 7 months. Sixteen grafts failed for technical reasons. Eight patients died between 1 and 21 months from infections or preexisting complications or for unknown reasons, three with functioning grafts. Actuarial 1-year graft survival is 24% and patient survival is 84%. A variety of techniques were used to handle exocrine secretions of 41 hemipancreas segmental grafts, 4 extended segmental grafts, and 4 whole pancreas grafts. Currently, 3 of 14 duct-open, 0 of 2 duct-ligated, 0 of 4 prolamine-injected, 6 of 19 silicone rubber-injected, and 4 of 10 jejunal anastomosed pancreatic grafts are functioning. Of 33 technically successful allografts, 5 in 12 conventionally immunosuppressed and 8 in 21 cyclosporin A (Cy A)-immunosuppressed recipients are functioning. Most technically successful grafts that failed were not biopsied or removed. In those that were biopsied, fibrosis was a dominant feature in all but one patient. In this patient endocrine and exocrine tissue was normal except for the absence of insulin-positive (beta) cells in the islets and an increase in glucagon-positive (alpha) cells, in contrast to the normal appearance of alpha and beta cells in islets at the time of the pancreas transplant. Currently, we perform pancreas transplants in diabetic patients who have previously received kidney transplants and therefore already require immunosuppression. For nonuremic patients, we perform pancreas transplant only if it is judged that their complications of diabetes exceed, or predictably will exceed, the potential side effects of chronic immunosuppression.     

Superior results with combined kidney-pancreas transplants.

From February of 1987 to February of 1991 the authors performed 23 pancreas transplants for Type I diabetes mellitus. Eight of the pancreas transplants were in patients who had a previous kidney transplant, 14 were simultaneous kidney and pancreas transplants, and 1 was in a pre-uremic diabetic. Two patients have been retransplanted after losing first grafts. All pancreata were retrieved from heart-beating cadaver donors. Pancreata were transplanted into the iliac fossa of the recipient using the iliac artery and vein as arterial inflow and venous outflow, respectively. Drainage of the pancreatic ductal system was accomplished by anastomosing either a patch or segment of duodenum surrounding the ampulla of Vater to the urinary bladder. All pancreata functioned initially with no patient requiring insulin 6 hours after surgery. Two grafts were lost early due to thrombosis of the venous drainage of the transplant; 4 grafts were lost to acute rejection; 3 were lost to chronic rejection; and 1 patient died with a functioning pancreas. One-year graft survival for all pancreatic grafts is 62 per cent. One-year patient survival is 96 per cent. One-year pancreatic graft and patient survival for the 14 combined kidney-pancreas transplants is 88 per cent and 100 per cent, respectively. Two kidneys transplanted with pancreata also were lost to acute rejection. Pancreas transplantation has proven to be a viable treatment alternative for selected patients with Type I diabetes mellitus. Long-term results are best when pancreas transplantation is done in combination with renal transplantation.     

Detection of serum-blocking factors by inhibition of allorosette formation in rats with long-surviving renal allografts following short-term postoperative ALS treatment.

Thirty-nine (LEW x BN)F1 kidneys were transplanted to LEW rats. Twenty-four untreated recipients survived for a mean time of 16.1 +/- 1.7 days (group 1). Fifteen recipients received 4 ml of antilymphocytic serum per rat (group 3). In the last group 10 recipients survived for more than 4 months. The spleen cells of these permanently surviving 10 rats were obtained by splenectomy and used in a graft-versus-host assay, and this assay showed that the reactivity of these cells was normal. Following splenectomy the animals were given an (LEW x BN)F1 skin allograft, followed 18 days by a second. After another 18 days (LEW x Buf)F1 "third party" skin allografts were transplanted to the same animals. Animals of group 2 rejected their first grafts with a mean survival time of 12.2 +/- 1.2 days, whereas the second grafts were rejected normally as were the third party grafts. Attempts were made to detect lymphocytotoxic antibodies and haemagglutinins before and after the transplantation of skin grafts and none could be found up to day 53. The sera of group 2 inhibited allorosette formation by 38%. This serum-blocking factor was donor specific. It is probable that the survival of the kidney transplants following antilymphocytic serum treatment was brought about by the development of blocking antibodies.