A Beham

Colonic J-Pouch vs. Coloplasty Following Resection of Distal Rectal Cancer

AbstractPURPOSE: In terms of functional outcome, there is evidence of the superiority of the colonic J-pouch over a straight coloanal anastomosis. Even though the colonic J-pouch was created to restore a neorectal reservoir, manometric data show that the volume of a short colonic J-pouch does not differ from a straight coloanal anastomosis. We speculate that the advantage of the colonic J-pouch is not in creating a larger neorectal reservoir, but rather related to decreased motility. Maurer and Z’graggen recently described a new colonic pouch design, performing a “transverse coloplasty” pouch. The purpose of this pilot study was to compare the feasibility and functional outcome of the 5-cm colonic J-pouch vs. the coloplasty pouch. METHODS: From February 2000 to June 2001, we randomized 40 consecutive patients with distal rectal cancer (<12 cm from the anal verge) into the J-pouch or coloplasty group. A low rectal resection and coloanal anastomosis was performed in all patients. Functional data were collected by a standardized questionnaire and anorectal manometry, preoperatively and six months postoperatively. Primary end points of the study were potentially differences of both groups regarding technical feasibility, stool frequency, and anorectal manometry. RESULTS: The construction of a coloplasty pouch was feasible in all cases of the coloplasty group, but not in 5 of 20 (25 percent) patients of the J-pouch group, because of colonic adipose tissue. Six months after operation or stoma closure, respectively, stool frequency was 2.75 ± 1 per day in the J-pouch group and 2 ± 2 per day in the coloplasty group. There was no significant difference in resting and squeeze pressure and neorectal volume between both groups, but an increased neorectal sensitivity in the coloplasty group. CONCLUSION: We found similar functional results in the coloplasty group compared to the J-pouch group. The neorectal sensitivity was increased in the coloplasty group. Therefore, the colonic coloplasty seems to be an attractive pouch design because of its feasibility, simplicity, and effectiveness.

Caspase 3 inhibition improves survival and reduces early graft injury after ischemia and reperfusion in rat liver transplantation

Background. Apoptosis plays a crucial role after ischemia-reperfusion in organ transplantation. It is executed by caspases and influenced by the rheostat of pro- and anti-apoptotic proteins of the bcl-2 family. This study investigated the effect of specific inhibition of caspases 3 and 7 on graft function, survival, and hepatic bcl-2 levels after liver transplantation. Methods. Lewis rats underwent syngeneic orthotopic liver transplantation after 16 hr of cold graft storage (in University of Wisconsin solution). Livers of donor animals treated with D(OMe)E(OMe)VD(OMe)-fluoromethylketone (specific inhibitor of apoptosis executor caspases 3 and 7), and appropriate control groups, were investigated. Early graft injury was quantified by measurement of bile flow and determination of microvascular graft injury by using in vivo fluorescence microscopy. Apoptosis and its regulation were examined by terminal deoxynucleotide transferase-mediated dUTP nick-end labeling staining and Western blot analysis of cell death effectors, respectively. Results. After specific in vivo caspase inhibition, Western blot analysis revealed inhibition of caspase-induced cleavage of poly-ADP-ribose-polymerase. Inhibition of caspases 3 and 7 resulted in a significantly decreased number of apoptotic endothelial cells and improved microvascular perfusion. A cell protective effect was also suggested by an increase of bcl-2 levels at 7 days. Most important, specific caspase blockade resulted in improved rat survival after liver transplantation. Conclusion. Specific inhibition of apoptosis executor caspases effectively reduces graft ischemia-reperfusion injury and improves survival in liver transplantation. Better tissue preservation after caspase inhibition correlates with reduced apoptosis execution, improved microvascular perfusion, and bcl-2 up-regulation. Therefore, specific caspase inhibition represents a promising regimen for clinical use in liver transplantation.

Benefit of Kupffer cell modulation with glycine versus Kupffer cell depletion after liver transplantation in the rat: effects on postischemic reperfusion injury, apoptotic cell death graft regeneration and survival*

Inhibition or destruction of Kupffer cells (KC) may protect against ischemia‐reperfusion (IR) induced primary graft nonfunction (PNF) in liver transplantation. Besides KC activation, PNF is characterized by microvascular perfusion failure, intrahepatic leukocyte accumulation, cell death and hepatocellular dysfunction. KCs can be inactivated by different agents including gadolinium chloride (GdCl3), methyl palmitate (MP) and glycine. The effects of three KC inactivators on IR‐injury after rat liver transplantation were compared in the present study. Lewis liver donors were treated with GdCl3, MP, glycine or saline (control). Liver grafts were transplanted following 24 h storage (UW solution). KC populations and IR damage were assessed by histologic analysis, quantitative real‐time polymerase chain reaction (RT‐PCR) and intravital microscopy. The number of hepatic ED‐1 positive macrophages was diminished after GdCl3 (114.8 ± 4.4/mm2 liver tissue) and MP treatment (176.0 ± 5.0), versus the glycine (263.9 ± 5.5) and control (272.1 ± 5.6) groups. All three treatment modalities downregulated phagocytic activity for latex particles, paralleled by reduced microvascular injury (acinar perfusion index, GdCl3: 0.75 ± 0.03; MP: 0.83 ± .03; glycine: 0.84 ± 0.03; 0.63 ± 0.03). Quantitative RT‐PCR revealed elevated myeloperoxidase mRNA after glycine versus GdCl3 and MP pretreatment (3.2‐ and 3.4‐fold, P = 0.011, respectively), without difference to controls (2.9‐fold of glycine). TNFα‐mRNA was reduced after glycine‐ (5.2‐fold), GdCl3‐ (19.7‐fold), MP‐treatment (39.5‐fold) compared with controls. However, profound prevention of intrahepatic cell death and liver graft failure was solely achieved with glycine preconditioning. Different than GdCl3 and MP, glycine modulates rather than destroys KCs. Glycine appears to preserve cell viability and to TNFα/leukocyte dependent organ regeneration capacity, which is related to increase graft survival following liver transplantation.

Adenoviral bcl-2 transfer improves survival and early graft function after ischemia and reperfusion in rat liver transplantation.

Background. Primary graft dysfunction due to ischemia and reperfusion injury represents a major problem in liver transplantation. The related cell stress may induce apoptosis, which can be suppressed by bcl-2. The purpose of the study was to investigate the effect of adenoviral bcl-2 gene transfer on early graft function and survival in rat liver transplantation. Methods. An adenoviral construct that transfers bcl-2 under the control of a tetracycline inducible promoter was generated (advTetOn bcl-2) and used with a second adenovirus that transfers the repressor protein (advCMV Rep). Forty-eight hours before explantation, donor rats were treated with advTetOn bcl-2/ advCMV Rep (n=7) and doxycyclin, with the control adenoviral construct advCMV GFP (n=8) or with doxycyclin alone (n=8). Liver transplantation was performed following 16 hours of cold storage (UW). Bcl-2 expression and intrahepatic apoptosis was assessed. Bile flow was monitored 90 min posttransplantation. The endpoint for survival was 7 days. Results. Bcl-2 was expressed in hepatocytes and sinusoidal lining cells. This was associated with a significant reduction of apoptotic sinusoidal lining cells and hepatocytes after 24 hours and 7 days. Bile production was significantly higher following bcl-2 pretreatment. Furthermore, bcl-2 transfer resulted in significantly improved survival (100% vs. 50% both control groups). Conclusions. Adenoviral bcl-2 transfer results in protein expression in hepatocytes and sinusoidal lining cells resulting in early graft function and survival enhancement after prolonged ischemia and reperfusion injury. The inhibition of apoptosis in the context of liver transplantation might be a reasonable approach in the treatment of graft dysfunction.