Off-pump CABG reduces complement activation but does not significantly affect peripheral endothelial function: a prospective randomized study

OBJECTIVE--Cardiac surgery initiates a systemic inflammatory response, which may affect endothelial function. The aim of this study was to investigate if off-pump CABG (OPCAB) reduces the postoperative inflammatory response and affects endothelial function less than conventional on-pump CABG. DESIGN--Fifty-two patients submitted for elective CABG were included in a prospective, randomized study. Twenty-six patients were operated with, and 26 without cardiopulmonary bypass (CPB). Plasma levels of complement (C3a), cytokines (IL-8, TNF-alpha), endothelin-1 and neopterin were measured before and during surgery and 2 and 24 h after surgery. Endothelial function was assessed by forearm plethysmography and acetylcholine infusion in 30 patients 2-4 h after surgery. RESULTS--C3a and neopterin concentrations were significantly higher during and early after surgery in the CPB group while TNF-alpha and IL-8 tended to be higher in the CPB group but the difference did not reach statistical significance. Endothelial function did not differ significantly between the two groups. CONCLUSION--OPCAB reduces complement activation compared with on-pump CABG but does not significantly affect TNF-alpha and IL-8 release or endothelial function.     

GDNF and BDNF alter the expression of neuronal NOS,c-Jun,and p75 and prevent motoneuron death following spinal root avulsion in adult rats

In the present study, we examined the effects of glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), and insulin growth factor (IGF-1) on adult motoneuron survival following spinal root avulsion. The expression of neuronal nitric oxide synthase (nNOS), c-Jun, and the low-affinity neurotrophin receptor (P75) following treatment with these neurotrophic factors was also examined. In control animals, approximately 80% of spinal motoneurons were nNOS positive at 3 weeks following the lesion, whereas in GDNF or BDNF treated animals no nNOS positive motoneurons were found at the same time point. Following injury and treatment with GDNF and BDNF increased numbers of motoneurons were c-Jun and P75 positive. By 6 weeks following the lesion, only approximately 28% of motoneurons persisted in control animals whereas about 90% of motoneurons survived injury following treatment with either GDNF or BDNF. In contrast, CNTF and IGF-1 were ineffective in either inhibiting nNOS expression or preventing motoneuron death. Our results provide in vivo evidence that the survival of injured adult mammalian motoneurons can be promoted by specific neurotrophic factors, and that this effect is associated with inhibition of nNOS expression and up-regulation of c-Jun and P75 expression.     

腰、骶脊神经前根撕脱伤对大鼠盆底肌运动神经元的影响

目的：观测大鼠脊神经前根撕脱伤对盆底肌运动神经元的存活及神经元中一氧化氮合酶（NOS）和N-甲基-D-天冬氨酸型受体（NMDAR）表达的影响。方法：取雄性SD大鼠25只，背部切口显露脊髓，拨断一侧L6～S2脊神经前根。动物分为5组，分别于术后第3、7、14、21、28天．取腰骶段脊髓进行还原型烟酰腺嘌呤二核侍酸（NADPH-d）组织化学、中件红复染和NMDA受体免疫组织化学染色观察及定量分析。结果：术后第3、7、14、21、28天，与对侧比较术侧前角运动神经元存活率分别为96％、85％、50％、35％和20％：术后第7d开始出现NOS阳性神经元，其标记率分圳为6％、40％、62％和41％。与对侧比较，术侧前角运动神经元NMDA受体亚单位表达改变，其中NMDAR，受体亚单位表达明显减少，NMDAR2H表达显著增高，NMDAR2A表达无明显变化。结论：前根撕脱伤可导致盆底肌运动神经元进行性死亡，NOS持续表达和NMDA受体亚单位的表达变化可能是导致神经元死亡的重要原因。     

Prefabrication of a free peripheral nerve graft following implantation on an arteriovenous pedicle

Extensive nerve injuries frequently necessitate the use of long autografts, and sources of expendable donor nerves are limited. It is for these cases that nerve transplantation would have its greatest potential. However, regeneration in the rejected allograft fails because of a lack of the positive neurotropic and neurotrophic influences physiologically provided by viable Schwann cells. This report aims to show the feasibility of vascularization of the peripheral nerve by prefabrication. The study was designed to vascularize an autogenous nerve graft segment by using an arteriovenous bundle in the rabbit. A 3.5-cm segment of sciatic nerve was harvested and implanted in between the femoral vessels, and was isolated from secondary revascularization by a custom-made tube. A peripheral nerve graft was prefabricated by implantation on the vascular pedicle, and neovascularization was evaluated by microangiography and histology. The graft exhibited early neovascularization on day 2, and numerous new capillaries were noted to restore primarily perineurial blood flow on day 7, then all along the graft on day 14. The viability of the Schwann cells was preserved, and the structural integrity of the graft was maintained. This is a preliminary report on secondary vascularization of a segment of an autogenous nerve to maintain the viability of Schwann cells and the integrity of the conduit. In the future, with the concomitant use of host immunosuppression or with more advanced pre-treatment methods, nerve allografts could be revascularized by vascular bundles. The current tempo of medical research will hopefully enable the use of fresh nerve allografts that are rendered less immunogenic by more refined techniques.     

Low-magnitude whole body vibration does not affect bone mass but does affect weight in ovariectomized rats

Mechanical loading has stimulating effects on bone architecture, which can potentially be used as a therapy for osteoporosis. We investigated the skeletal changes in the tibia of ovariectomized rats during treatment with whole body vibration (WBV). Different low-magnitude WBV treatment protocols were tested in a pilot experiment using ovariectomized rats with loading schemes of 2 × 8 min/day, 5 days/week (n = 2 rats per protocol). Bone volume and architecture were evaluated during a 10 week follow-up using in-vivo microcomputed tomography scanning. The loading protocol in which a 45 Hz sine wave was applied at 2 Hz with an acceleration of 0.5g showed an anabolic effect on bone and was therefore further analyzed in two groups of animals (n = 6 each group) with WBV starting directly after or 3 weeks after ovariectomy and compared to a control (non-WBV) group at 0, 3, 6 and 10 weeks’ follow-up. In the follow-up experiment the WBV stimulus did not significantly affect trabecular volume fraction or cortical bone volume in any of the treatment groups during the 10 week follow-up. WBV did reduce weight gain that was induced as a consequence of ovariectomy. We could not demonstrate any significant effects of WBV on bone loss as a consequence of ovariectomy in rats; however, the weight gain that normally results after ovariectomy was partly prevented. Treatment with WBV was not able to prevent bone loss during induced osteoporosis.     

The behavioral and immunological effect of GM-1 ganglioside on nerve root regeneration following C5 nerve root avulsion in a rat model

Preganglionic nerve root avulsion precludes sensory return, but motor regeneration is possible with sparing of motoneurons. The effect of GM-1 ganglioside treatment was studied with parallel evaluation of the autoimmune response. Rats (N=64) received injections of either GM-1 ganglioside or saline for 30 days following either C5 root avulsion or a hemilaminectomy control. The Bertelli grooming test assessed functional return. Before sacrifice at 5 months, serum was collected for enzyme-linked immunoabsorbent assay testing. Only 44% of the rats treated with ganglioside had a good functional outcome compared with 50% for controls. Although 17% of the rats developed anti GM-1 antibodies, there was no functional or histological evidence of neuropathy in any of the rats. We conclude that ganglioside treatment did not enhance recovery from peripheral nerve injury. Although an immune response was present in some rats, no overt signs of neuropathy were observed.     

The use of contrast media in deceased kidney donors does not affect initial graft function or graft survival

Patients receiving cadaveric kidney transplants often experience delayed graft function. As iodinated contrast media injection (ICMI), necessary for cerebral angiography, which is often used to diagnose brain death, can be nephrotoxic, we compared renal function recovery (RFR) and 1-year and long-term graft survival according to the method used to diagnose brain death. Data from 9921 cadaveric kidneys, transplanted between 1 January 1998 and 31 December 2003, were retrieved from the French National Registry for organ donation. We defined RFR as the number of days for the recipient to reach a plasma creatinine less than 250 mumol/l, and/or a 24-h urine output greater than 1000 ml. RFR and 1-year and long-term graft survival were compared between four different donor groups (according to ICMI and diabetes mellitus). A total of 41.5% of deceased donors received ICMI before organ procurement and 1.95% of them were diabetic. History of ICMI or diabetes in the donor did not influence RFR or 1-year graft survival. Long-term graft survival was decreased in the group of patients transplanted with a diabetic graft as compared to patients transplanted with a non-diabetic graft (P=0.001). History of ICMI in the donor did not affect long-term graft survival in the non-diabetic donor group (P=0.2); however, in the diabetic group, ICMI tended to decrease long-term graft survival (P=0.056). ICMI did not affect RFR or graft survival in non-diabetic deceased donors. However, its use in diabetic deceased donors requires further study.     

Fracture callus engulfing a peripheral nerve does not affect its function: an experimental study in rabbits

The fate of a peripheral nerve engulfed in fracture callus is not known. We investigated the impact of envelopment of the sciatic nerve by fracture callus using a New Zealand rabbit femoral fracture model. The sciatic nerve was mobilized and coiled around the ipsilateral femur, which was surgically fractured, shortened, and osteosynthesized. Bony union was achieved, and callus engulfed the sciatic nerve in all animals. Nerve function was evaluated clinically and by conduction studies preoperatively and postoperatively. Although the nerve function in terms of clinical evaluation, amplitude, motor latency, and spontaneous activity deteriorated immediately postoperatively, recovery was evident in the following weeks indicating that the detected nerve dysfunction was attributable to the surgical mobilization. In addition, histologic and quantitative histomorphometric analyses proved that in none of the animals did the callus compress the sciatic nerve whereas an impressive process of axonal regeneration took place despite callus maturation. Results of our study suggest that callus, engulfing a peripheral nerve, does not compress it and the nerve appears to be intact in an osseous canal. This results in preservation of the integrity and function of the nerve, which may have significant clinical applications.     

Delayed transplantation of human neurons following brain injury in rats: a long-term graft survival and behavior study

The NTera2 (NT2) cell line is a homogeneous population of cells, which, when treated in vitro with retinoic acid, terminally differentiate into postmitotic neuronal NT2N cells. Although NT2N neurons transplanted in the acute (24 h postinjury) period survive for up to 1 month following experimental traumatic brain injury (TBI), nothing is known of their ability to survive for longer periods or of their effects when engrafted during the chronic postinjury period. Adult male Sprague-Dawley rats (n = 348; 360-400 g) were initially anesthetized and subjected to severe lateral fluid-percussion (FP) brain injury or sham injury. At 1 month postinjury, only brain-injured animals showing severe neurobehavioral deficits received cryopreserved NT2N neurons stereotaxically transplanted into three sites in the peri-injured cortex (n = 18). Separate groups of similarly brain-injured rats received human fibroblast cells (n = 13) or cell suspension vehicle (n = 14). Sham-injured animals (no brain injury) served as controls and received NT2N transplants (n = 24). All animals received daily immunosuppression for three months. Behavioral testing was performed at 1, 4, 8, and 12 weeks post-transplantation, after which animals were sacrificed for histological analysis. Nissl staining and anti-human neuronal specific enolase (NSE) immunostaining revealed that NT2N neurons transplanted in the chronic post-injury period survived up to 12 weeks post-transplantation, extended processes into the host cortex and immunolabeled positively for synaptophysin. There were no statistical differences in cognitive or motor function among the transplanted brain-injured groups. Long-term graft survival suggests that NT2N neurons may be a viable source of neural cells for transplantation after TBI and also that these grafts can survive for a prolonged time and extend processes into the host cortex when transplanted in the chronic post-injury period following TBI.     

化学去细胞异体神经复合肝细胞生长因子修复周围神经缺损的研究

目的 研究化学去细胞异体神经复合人肝细胞生长因子(HGF)修复周围神经缺损的作用.方法 体外试验检测携带人肝细胞生长因子基冈的重组腺病毒(Ad-HGF)对小鼠骨骼肌细胞的转染效率以及转染细胞对目的 蛋白的表达.化学玄细胞异体神经修复大鼠坐骨神经10mm缺损后,近、远端吻合口附近肌肉分别注射腺病毒介导的人肝细胞生长因子(Ad-HGF),与自体神经移植组对照,通过步态分析、肌肉湿重测定、轴突生长速率测定、神经电生理、计算机图像分析等指标评价神经移植后再生效果.结果 流式细胞仪结果表明,随着病毒滴度的增加,Ad-HGF对骨骼肌细胞的转染不断增加.骨骼肌细胞对目的 蛋白(HGF)的表达可以持续两周.大鼠动物实验术后16周,去细胞异体神经可以修复周罔神经缺损,同自体神经移植对比,肝细胞生长因子明显增强了去细胞异体神经的神经再生能力.结论 复合肝细胞生K因子的化学去细胞异体神经能促进神经轴突牛长速度,显著增加移植物内新生血管,满意修复一定长度周围神经缺损,可以成为一种有效的周围神经组织工程修复材料.     

Prolonged donor ischemic time does not adversely affect long-term survival in adult patients undergoing cardiac transplantation

OBJECTIVE: With liberalization of donor eligibility criteria, organs are being harvested from remote locations, increasing donor ischemic times. Although several studies have evaluated the effects of prolonged donor ischemic times on short-term survival and graft function, few have addressed concerns regarding long-term survival. METHODS: Over the last 11 years, 819 consecutive adults underwent cardiac transplantation at Columbia Presbyterian Medical Center. Recipients were separated into the following 4 groups based on donor ischemic time: <150 minutes, 150 to 200 minutes, 200 to 250 minutes, and >250 minutes. Statistical analysis included Kaplan-Meier survival and Cox proportional hazard models to identify predictors of long-term survival. RESULTS: Donor ischemic time was 120.1 +/- 21.1 minutes for group 1 (n = 321), 174.1 +/- 14.7 minutes for group 2 (n = 264), 221.7 +/- 14.6 minutes for group 3 (n = 154), and 295.5 +/- 37.1 minutes for group 4 (n = 80) (P <.001). There were no significant differences in recipient age, donor age, etiology of heart failure, United Network for Organ Sharing status, or history of previous cardiac surgery among the groups (P = NS). Prolonged donor ischemic time did not adversely affect long-term survival, with actuarial survival at 1, 5, and 10 years of 86.9%, 75.2%, and 56.4% for group 1; 86.2%, 76.9%, and 50.9% for group 2; 86.4%, 71.0%, and 43.7% for group 3; and 86.7%, 70.1%, and 50.9% for group 4 (P =.867). There was no significant difference in freedom from transplant coronary artery disease among the 4 groups (P =.474). CONCLUSIONS: Prolonged donor ischemic time is not a risk factor for decreased long-term survival. Procurement of hearts with prolonged donor ischemic time is justified in the setting of an increasing recipient pool with a fixed donor population.     

Addition of sirolimus to cyclosporine delays the recovery from delayed graft function but does not affect 1-year graft function

Delayed graft function (DGF) has long been identified as one of the main correlates of poor graft survival in cadaveric renal transplantation, but the factors that affect its onset and duration are not fully elucidated. The impact of two immunosuppressive protocols on the incidence and length of DGF among kidney transplant recipients of a suboptimal organ was evaluated. Patients were randomly treated with corticosteroids (CS); low-dose cyclosporine (CsA) and sirolimus (SRL; group 1; n = 42); or CS, full-dose CsA, and mycophenolate mofetil (group 2; n = 48). All recipients received immunoprophylaxis with basiliximab. After 3 mo, group 1 discontinued CsA and continued with SRL, whereas group 2 continued the same treatment. The incidence of DGF was similar in the two groups (group 1 = 52.4%; group 2 = 58.3%), whereas its duration was significantly higher in the group 1 (19.0 +/- 6.0 versus 10.3 +/- 3.2 d; P = 0.001). Both groups showed 100% actuarial graft and patient survival at 1-yr. Among DGF patients, serum creatinine (sCr) at discharge was significantly worse in group 1 (sCr, 3.0 +/- 1.0 versus 1.5 +/- 0.2 mg/dl; calculated creatinine clearance, 31.2 +/- 9.3 versus 61.1 +/- 10 ml/min; P = 0.001). During the first year, the former group displayed a significant improvement of graft function, such that at 1-yr, no difference could be measured between groups (sCr, 1.8 +/- 0.5 versus 1.7 +/- 0.4 mg/dl; calculated creatinine clearance, 51.5 +/- 10.2 versus 53.3 +/- 9.4 ml/min). In conclusion, in de novo renal transplanted patients, the administration of SRL, in combination with low-dose CsA, is associated with a delayed recovery from DGF but does not worsen 1-yr graft function.     

Effect of oblique nerve grafting on peripheral nerve regeneration in rats

Current methods of peripheral nerve repair are to rejoin cut nerve stumps directly or to bridge large gaps with autologous nerve grafts. In both cases the surface of nerve stump endings is typically cut perpendicularly to the long axis of the nerve. The outcome of such operations, however, is still not satisfactory. In this study, we examine the effect of oblique nerve cutting and grafting on morphological as well as functional features of regeneration. In adult rats, sciatic nerve was cut and rejoined either directly or using an autologous graft, at 90 degrees or 30 degrees angle. Functional regeneration was assessed by walking track analysis during 12-week follow-up. Afterwards muscle weight was measured and histological studies were performed. The latter included nerve fibers and Schwann cells counting, as well as visualization of scar formation and epineural fibrosis. Nerves cut obliquely and rejoined showed better functional recovery than perpendicularly transected. Similar effect was observed after oblique grafting when compared to perpendicular one. Numbers of nerve fibers growing into the distal stump of the nerve as well as the number of Schwann cells were significantly higher in obliquely than in perpendicularly operated nerves. Moreover, growing axons were arranged more regularly following oblique treatment. These data indicate that joining or grafting the nerve stumps at acute angle is a more profitable method of nerve repair than the standard procedure performed at right angle.     

Citicoline improves functional recovery, promotes nerve regeneration, and reduces postoperative scarring after peripheral nerve surgery in rats

BACKGROUND: Citicoline has been shown to have beneficial effects in a variety of CNS injury models. The aim of this study was to test the effects of citicoline on nerve regeneration and scarring in a rat model of peripheral nerve surgery. METHODS: Seventy adult Sprague-Dawley rats underwent a surgical procedure involving right sciatic nerve section and epineural suturing. Rats were assigned to the control or experiment groups to receive a topical application of 0.4 mL of saline or 0.4 mL (100 micromol/L) of citicoline, respectively. Macroscopic, histological, functional, and electromyographic assessments of nerves were performed 4 to 12 weeks after surgery. RESULTS: In the control versus citicoline-treated rats, SFI was -90 +/- 1 versus -84 +/- 1 (P < .001), -76 +/- 4 versus -61 +/- 3 (P < .001), and -66 +/- 2 versus -46 +/- 3 (P < .001) at 4, 8, and 12 weeks after surgery, respectively. At 12 weeks after surgery, axon count and diameter were 16400 +/- 600 number/mm(2) and 5.47 +/- 0.25 microm versus 22250 +/- 660 number/mm(2) (P < .001) and 6.65 +/- 0.28 microm (P < .01) in the control and citicoline-treated groups, respectively. In citicoline-treated rats, histomorphological axonal organization score at the repair site was (3.4 +/- 0.1) significantly better than that in controls (2.6 +/- 0.3) (P < .001). Peripheral nerve regeneration evaluated by EMG at 12 weeks after surgery showed significantly better results in the citicoline group (P < .05). Nerves treated with citicoline demonstrated reduced scarring at the repair site (P < .001). CONCLUSION: Our results demonstrate that citicoline promotes regeneration of peripheral nerves subjected to immediate section suturing type surgery and reduces postoperative scarring.