Evolution of clinical intestinal transplantation: improved outcome and cost effectiveness

Logistics and technique for procurement of intestinal, pancreatic, and hepatic grafts from the same donor

OBJECTIVE

To assess a technique for simultaneous recovery of the intestine, pancreas, and liver from the same donor.

SUMMARY BACKGROUND DATA

With the more frequent use of pancreatic and intestinal transplantation, a procurement procedure is needed that permits retrieval of both organs as well as the liver from the same cadaveric donor for transplantation to different recipients. It is believed by many procurement officers and surgeons, however, that this objective is not technically feasible.

METHODS

A technique for simultaneous recovery of the intestine, pancreas, and liver was used in 13 multiorgan cadaver donors during a 26-month period, with transplantation of the organs to 33 recipients. The intestine was removed from 11 donors separately and in continuity with the pancreas in the other 2. Six additional pancreases were excised and transplanted separately. Thirteen livers were retrieved, one of which was discarded because of steatorrhea. Ten of the remaining 12 livers were transplanted intact; the other 2 were split in situ and used as reduced-size hepatic allografts in four recipients.

RESULTS

None of the 11 intestinal, 6 pancreatic, 2 intestinal-pancreatic, or 14 whole or partial liver allografts sustained serious ischemic injury or were lost as a result of technical complications. One liver recipient died 25 months after surgery of recurrent C virus hepatitis. The other 32 recipients had adequate allograft function with a mean follow-up of 8 months.

CONCLUSION

It was possible using the described technique to retrieve intestine, pancreas, and liver allografts safely from the same donor and to transplant these organs to different recipients.

Small bowel motility: ready for prime time?

The primary function of the small bowel is the absorption of nutrients, and the motor patterns of the healthy bowel are intended to promote that function. The motor patterns of the small bowel are the result of close interaction between the enteric nervous system, extrinsic nerves, regulatory peptides, and the intestinal smooth muscle. The basic electrical rhythm governing intestinal contractions is determined by specialized pacemaker cells called the interstitial cells of Cajal. Diseases affecting any of these components may result in intestinal dysmotility and its associated symptoms. Although transit studies and intestinal manometry are helpful in the diagnosis of dysmotility, our understanding of pathophysiology is hampered by the difficulties involved in obtaining and analyzing intestinal tissue. Treatment of intestinal dysmotility relies on dietary manipulations and nutritional support (enteral or parenteral) because there is no drug therapy that can effectively enhance the propulsive function of the small bowel. Small bowel transplantation remains a life-saving intervention for patients who fail to respond to other therapies.

Small bowel transplantation

The development of small bowel transplantation has long been hindered by the immunological and infectious barriers peculiar to the small bowel. Gradual progress has been achieved during the past decade with the use of tacrolimus and the availability of better anti-infection prophylaxis. The current status of small bowel transplantation as a life-saving option for patients failing on total parenteral nutrition and those who have developed irreversible liver failure is undisputed. Small bowel transplantation can be performed as either an intestine-only graft or as part of a composite graft with the liver and, on occasion, other organs. The various techniques of donor and recipient operations are relatively standardized. Despite the progress made, the most common causes of death and graft loss continue to be sepsis, rejection, and lymphomas. Further progress can be achieved by development of more effective immunosuppressive and immunomodulatory strategies. The role of inducing chimerism by adjuvant donor-specific bone marrow transfusions to promote graft tolerance is uncertain. Until the mortality and graft losses are further reduced, the role of small bowel transplantation will be limited to a salvage procedure for failure of total parenteral nutrition rather than a primary treatment of intestinal failure.

Tacrolimus: a further update of its pharmacology and therapeutic use in the management of organ transplantation

Tacrolimus (FK-506) is an immunosuppressant agent that acts by a variety of different mechanisms which include inhibition of calcineurin. It is used as a therapeutic alternative to cyclosporin, and therefore represents a cornerstone of immunosuppressive therapy in organ transplant recipients. Tacrolimus is now well established for primary immunosuppression in liver and kidney transplantation, and experience with its use in other types of solid organ transplantation, including heart, lung, pancreas and intestinal, as well as its use for the prevention of graft-versus-host disease in allogeneic bone marrow transplantation (BMT), is rapidly accumulating. Large randomised nonblind multicentre studies conducted in the US and Europe in both liver and kidney transplantation showed similar patient and graft survival rates between treatment groups (although rates were numerically higher with tacrolimus- versus cyclosporin-based immunosuppression in adults with liver transplants), and a consistent statistically significant advantage for tacrolimus with respect to acute rejection rate. Chronic rejection rates were also significantly lower with tacrolimus in a large randomised liver transplantation trial, and a trend towards a lower rate of chronic rejection was noted with tacrolimus in a large multicentre renal transplantation study. In general, a similar trend in overall efficacy has been demonstrated in a number of additional clinical trials comparing tacrolimus- with cyclosporin-based immunosuppression in various types of transplantation. One notable exception is in BMT, where a large randomised trial showed significantly better 2-year patient survival with cyclosporin over tacrolimus, which was primarily attributed to patients with advanced haematological malignancies at the time of (matched sibling donor) BMT. These survival results in BMT require further elucidation. Tacrolimus has also demonstrated efficacy in various types of transplantation as rescue therapy in patients who experience persistent acute rejection (or significant adverse effect's) with cyclosporin-based therapy, whereas cyclosporin has not demonstrated a similar capacity to reverse refractory acute rejection. A corticosteroid-sparing effect has been demonstrated in several studies with tacrolimus, which may be a particularly useful consideration in children receiving transplants. The differences in the tolerability profiles of tacrolimus and cyclosporin may well be an influential factor in selecting the optimal treatment for patients undergoing organ transplantation. Although both drugs have a similar degree of nephrotoxicity, cyclosporin has a higher incidence of significant hypertension, hypercholesterolaemia, hirsutism and gingival hyperplasia, while tacrolimus has a higher incidence of diabetes mellitus, some types of neurotoxicity (e.g. tremor, paraesthesia), diarrhoea and alopecia.

CONCLUSION

Tacrolimus is an important therapeutic option for the optimal individualisation of immunosuppressive therapy in transplant recipients.

Intestinal transplantation: 1997 report of the international registry. Intestinal Transplant Registry

BACKGROUND

Small bowel transplantation is an evolving procedure. We reviewed the world experience since 1985 to determine the current status of this procedure.

METHODS

All of the known intestinal transplant programs were invited to contribute to an international registry using a standardized report form.

RESULTS

Thirty-three intestinal transplant programs provided data on 273 transplants in 260 patients who were transplanted on or before February 28, 1997. The number of procedures per year has increased at a linear rate since 1990, with 58 transplants performed in 1996. Two-thirds of the recipients were children or teenagers. The short gut syndrome was the most common indication for transplantation. The types of transplants included the small bowel with or without the colon (41%); the intestine and liver (48%); and multivisceral grafts (11%). The 1-year graft/patient survival for transplants performed after February 1995 was 55%/69% for intestinal grafts; 63%/66% for small bowel and liver grafts; and 63%/63% for multivisceral grafts. Transplants since 1991 and programs that had performed at least 10 transplants had significantly higher graft survival rates. Seventy-seven percent of the current survivors had stopped total parenteral nutrition (TPN) and resumed oral nutrition.

CONCLUSIONS

Transplantation has become a lifesaving procedure for (1) patients with intestinal failure who cannot be maintained on total parenteral nutrution and (2) patients who require abdominal evisceration to completely remove locally aggressive tumors. The 5-year survival rate of intestinal transplantation with large series is comparable to lung transplantation.