The influence of donor specific vertebral body derived bone marrow cell infusion on canine islet allograft survival without irradiation conditioning of the recipient

In recent studies in rodents, it was shown, that donor specific tolerance towards islet allografts without irradiation therapy of the recipient is induced by bone marrow cell infusion in combination with temporary immunosuppression. In the present study, the effect of donor specific bone marrow cell (DBMC) infusion at the time of intrahepatic islet allotransplantation without irradiation conditioning of the recipient was investigated in the canine model, paralleling ongoing clinical trials. It was observed, that unfractionated bone marrow cells given simultaneous to islet allografts led to higher frequencies of rejection periods and decreased islet allograft survival, when administered to recipients immunosuppressed with Cyclosporine A only. In contrast, an additional short inductive treatment of the recipient with an anti-dog-T-lymphocyte monoclonal antibody (5G2) abrogated the enhanced immunogenicity of the unfractionated bone marrow preparation, prolonging islet allograft survival with no rejection episodes observed during the immunosuppressive treatment with Cyclosporine. The composition of bone marrow cells might have contributed to the higher immunogenicity, since the percentage of MHC-class II antigen bearing cells is similar to man, but significantly higher than compared to rodents. It is therefore suggested, that further studies should encompass both timing of bone marrow cell infusion, appropriate immunosuppression and strategies to functionally inactivate mature MHC-class-II positive cells prior to DBMC infusion.

Compensatory recovery of vagal control of hemodynamics after unilateral vagotomy

This study investigated whether each part of the heart is evenly innervated by the left or right vagus and observed the mechanism of compensatory recovery after unilateral cervical vagotomy. HR, BP, LVSP and +/-dp/dt max all decreased one week after left vagotomy, whereas only BP and -dp/dt max decreased one week after right vagotomy. Western blot analyses revealed that the expression of M(2) receptors in the left atrium and left ventricle was upregulated after subacute (1 week) left/right vagotomy. However, significantly more cholinesterase-positive nerves in LV and RV were seen one week after unilateral vagotomy compared to the sham-operated group. In addition, baroreflex sensitivity was increased after subacute right vagotomy. The decreasing effects of ACh (0.5 microg/kg) on LVSP and +/-dp/dt max (but not on HR and BP) were facilitated by subacute unilateral vagotomy. Our present experiments indicate that 1) the working myocardium is innervated bilaterally by the vagus, 2) ventricular contractility is influenced more by denervation of the left than the right vagus and 3) up-regulation of M(2) muscarinic receptors in the left heart, increase of cholinergic nerves, and high baroreflex sensitivity could be involved in the mechanism of compensatory hemodynamic recovery via contralateral vagus overactivity, thereby amplifying contralateral vagal activity and decreasing cardiac contractility.

Absence of the preemptive analgesic effect of dextromethorphan in total knee replacement under epidural anesthesia

BACKGROUND

Previous studies have shown that dextromethorphan (DM), a N-methyl-D-aspartate (NMDA) receptor antagonist, produces a preemptive analgesic effect on post-operative pain. The aim of this study was to further examine the preemptive analgesic effect of intramuscular (i.m.) DM injection on unilateral total knee replacement (TKR).

METHODS

Sixty-four ASA I-III patients scheduled for unilateral TKR surgery were randomly allocated into three groups in a prospective double-blind manner. All patients received epidural anesthesia without any premedication. An initial bolus dose of 2% lidocaine (15-20 mL) followed by a maintenance dose of 8-10 mL/h was decided. Fentanyl (1.5 micrograms/kg) and diazepam (2 mg) were given i.v. before epidural catheter insertion. The epidural catheter was placed via the L2-L3 or L3-L4 interspace and advanced for 5 cm cephalad [corrected]. Patients received i.m. injection of 20 mg chlorpheniramine (CPM) before surgery as control (group C, n = 22). For the study groups, patients were given an i.m. injection containing 40 mg DM and 20 mg CPM, before (group B, n = 22) or after surgery (group A, n = 20), respectively. Postoperation, patients received intravenous morphine by means of a patient controlled analgesia (PCA) device for pain relief. The time to the first pull of PCA trigger, morphine consumption, worse pain scores (resting and incidental), and analgesics related side effects were recorded at 1, 2, 4, 8, 24, 48 and 72 h after surgery.

RESULTS

The time from the end of operation to the first PCA trigger were 31.2 +/- 5.2 min in group C, 67.3 +/- 11.1 min in group B (P < 0.05, compared with group C) and 61.8 +/- 7.2 min in group A (P < 0.05, compared with group C) respectively. The relevant pain score at resting, observed at the 8 h postoperatively was respectively 4.2 +/- 0.1 in group C, 3.7 +/- 0.2 in group B (P < 0.05, compared with group C) and 3.4 +/- 0.2 in group A (P < 0.05, compared with group C); and at the 24 h was 3.1 +/- 0.2 in group C, 2.4 +/- 0.2 in group B (P < 0.05, compared with group C) and 2.5 +/- 0.1 in group A (P < 0.05, compared with group C) respectively. There were no significant differences in actual morphine delivery and frequency of PCA triggering at all time among the three groups. Moreover, there was also no significant statistic difference in morphine-associated side effects among the three groups.

CONCLUSIONS

In the present study, we failed to observe any preemptive analgesic effect of DM (40 mg, i.m.) on postoperative pain in patients who received TKR under epidural anesthesia, however, DM given either before or after surgery augmented other analgesic (morphine) to offer a better pain relief.

Rhabdomyolysis after a long-term thoracic surgery in right decubitus position

We report a rare case who developed rhabdomyolysis associated with the use of the right decubitus position for 10 h during thoracotomy with lobectomy. It appears that an increasing of the compartment pressure may induce reperfusion injury of the ischemic muscle by prolonged compression of the gluteal and flank muscles against the operation table. Early recognition and aggressive treatment with intravenous fluid and diuresis may prevent the development of acute renal failure. Adequate prevention in high-risk patients, early diagnosis and aggressive treatment are the keys to a successful recovery.

Intra-articular ketamine for pain control following arthroscopic knee surgery

BACKGROUND

In an attempt to demonstrate the peripheral effect of ketamine on the synovia of knee joint and to smoothen the recovery from arthroscopic knee surgery, this study was designed to evaluate the analgesic effect of intra-articular ketamine injection after knee arthroscopy.

METHODS

In a double blind randomized study, 60 patients were assigned to three groups. Group A patients received saline 5 mL intra-articularly after closure of the surgical wound to serve as control; group B patients received ketamine 0.5 mg/kg of body weight intra-muscularly to rule out the systemic effect and group C patients received ketamine 0.5 mg/kg of body weight diluted with saline up to 5 mL intra-articularly. After surgery, patients were evaluated for pain with visual analogue scale (VAS 0 to 10) for 24 h with the operated leg in the position of extension rest and active flexion of the knee joint to 60 degree angle. Rescue pethidine (1 mg/kg of body weight) was given intra-muscularly for pain relief at request every 4 h postoperatively if necessary. The time to first rescue analgesic request was recorded, and the total doses of pethidine were calculated.

RESULTS

The results showed no difference in the VAS pain scores at rest and during active motion in the range of 60 degree among three groups during a 24 h observation.

CONCLUSIONS

Ketamine had been reported to have peripheral analgesic effects with variable duration on measurements of pain and hyperalgesia. However, in the present study, we failed to demonstrate that ketamine could provide a clinically relevant peripheral analgesic effect for postoperative arthroscopic pain.

Transplantation of islets of Langerhans in patients with insulin-requiring diabetes mellitus undergoing orthotopic liver transplantation--the Miami experience

Most patients with cirrhosis of the liver have detectable insulin resistance. In 60-80% of patients with cirrhosis, impaired glucose tolerance can be uncovered; approximately 20% of these patients eventually develop overt diabetes. Theoretically, insulin resistance and glucose intolerance could be improved or reversed by orthotopic liver transplantation alone or in association with a simultaneous transplant of pancreatic islet cells from the same donor. To investigate these possibilities we initiated a pilot study of simultaneous liver and pancreatic islet cell transplantation in seven patients with diabetes and liver cirrhosis. Donor bone marrow cells were also infused to enhance the acceptance of the grafts. Seven patients who received only orthotopic liver transplantation and donor bone marrow cells were used as historical controls. The preliminary results of this pilot trial suggest that islet cell transplantation in conjunction with orthotopic liver transplantation improves glucose metabolism in patients with liver cirrhosis in association with reduced insulin requirements and HbA1c levels. These results were evident in spite of pre- and post-transplant basal C-peptide levels that were unchanged. Further evaluation of the effects of orthotopic liver transplantation with or without islet cell transplantation will require a randomized prospective trial including accurate metabolic evaluation with the euglycemic insulin clamp technique.

Long-term function (6 years) of islet allografts in type 1 diabetes

Eight type 1 diabetic patients, ages 29-41 years, with mean diabetes duration of 23 years (range 18-29 years) received islet transplants from 1 to 5 donors. Seven patients had stable kidney allografts 1-11 years before the islet transplant, and one patient had a simultaneous islet-kidney allograft. Patients' blood glucose control was poor as reflected by the mean +/- SD HbA1c of 9.1 +/- 1.7% before transplant. Of the first three patients, two (1 and 3) achieved insulin independence for 36 and 38 days, respectively. Two recipients rejected their islet grafts within 1 month (2 and 8) and therefore were excluded from analysis. The HbA1c and insulin requirement of the six remaining patients who had persistent islet function for more than 60 days was significantly reduced from 9.3 +/- 1.9 to 6.4 +/- 1.0% (P = 0.002) and from 0.75 +/- 0.15 to 0.35 +/- 0.12 U x kg(-1) x day(-1) (P < 0.001), respectively. The two patients with the longest graft survival (4 and 6) achieved a normalization or near-normalization of their HbA1c levels during 6 years in the absence of severe episodes of hypoglycemia. As demonstrated by a decline in C-peptide response during Sustacal challenge tests over a 6-year period, there was a diminution of islet allograft function over time, despite persistence of normal or near normal HbA1c. We concluded that transplantation of allogeneic islets with an islet mass comparable with whole or segmental pancreas transplants in type 1 diabetic patients can result in long-term islet allograft function; further, we concluded that, in conjunction with small dosages of exogenous insulin, a functioning islet allograft can result in near-normalization of blood glucose levels and significant improvement in HbA1c. The occurrence of severe hypoglycemic episodes observed for patients in the Diabetes Control and Complications Trial was not observed in recipients with functioning islet transplants, despite the continuous need for exogenous insulin therapy to sustain normal HbA1c over the 6-year follow-up. The significant improvement in metabolic control observed for the patients described in this study, and the potential to significantly decrease or halt the progression of diabetic complications, support the continued application of islet allotransplantation as a treatment modality for type 1 diabetic patients.

Expression of a specific subset of CD44 variant transcripts in NOD pancreatic islets

Adhesion of lymphocytes to the endothelial venules inside the islets of Langerhans seems to initiate the infiltration of islets in NOD mice. An overexpression of the lymphocyte surface molecule CD44 in infiltrated NOD islets compared with peripheral blood lymphocytes was recently reported. The CD44 protein family includes a variety of molecules generated by alternative RNA splicing from 10 variant exons (v1-v10). By using reverse transcriptase-polymerase chain reaction followed by Southern blotting and hybridization to exon-specific cDNA probes, we investigated the expression of CD44 isoforms in highly purified islets of Langerhans from 4- and 10-week-old NOD mice. At least six CD44 isoforms were strongly overexpressed in NOD islets at 4 and 10 weeks when compared with age-matched BALB/c islets. Controls in different tissues indicate that these variants are specifically increased in the islets from the NOD strain. Islets from the NOD-scid/scid strain also expressed these variant exons. Splenocytes from BALB/c did not express CD44 isoforms, whereas splenocytes from 4-week-old NOD mice did express CD44 variants. Treatment with inflammatory mediators induced new isoforms; however, these transcripts have a different variant exon composition from that found in NOD mice islets. These results suggest that some isoforms are expressed very early in the development of insulitis by a component of the NOD islet itself and underscore a possible role of CD44 in islet infiltration.

Improved functional survival of human islets of Langerhans in three-dimensional matrix culture

The current study evaluates functional survival of human islets maintained in tissue culture for up to 4 wk in suspension media (CMRL-1066 with supplements) and contrasts these results with immobilizing three-dimensional matrices (agarose or alginate). The absolute number and volume of islets retrieved from agarose is significantly higher after two and four wk of culture compared to conventional free-floating media. In vitro function of islets, assessed by insulin/DNA content, insulin secretion into the culture media over 24 h and glucose-theophylline stimulated insulin release in a dynamic perifusion system, was not significantly different between free-floating and matrix preserved islets. In vivo islet function was evaluated by the effectiveness for reversal of insulin-dependent diabetes mellitus by transplantation of the islets under the kidney capsule of nude mice. Although adequate insulin responses to glucose were seen after culture in conventional or matrix media, only agarose embedded islets were consistently able to induce normoglycemia in diabetic recipients after 14 days of culture. Additional transplantation experiments defined the threshold level required to reverse diabetes to be between 1,000 and 1,500 agarose preserved islets. Our data suggest improved engraftment of human islets after agarose culture. This culture method may be of benefit for the accumulation of functionally competent human islets, thus facilitating the implementation of clinical protocols that utilize freshly isolated islets from multiple donors without the need for cryopreservation.

Induction of donor-specific tolerance to rat islet allografts by intrathymic inoculation of solubilized spleen cell membrane antigens

The development of strategies that will allow permanent survival of islet allografts without continuous host immunosuppression continues to be the most important goal in the field of pancreatic islet cell transplantation. In our study, we demonstrated that intrathymic inoculation of allogeneic spleen cell membrane antigens with a single dose of anti-lymphocyte serum induces an unresponsive state that permits survival of a subsequent pancreatic islet allograft to an extrathymic site (renal subcapsular space). This effect is donor specific and cannot be reproduced by the intravenous injection of spleen cell membrane antigens. Our results offer a potential approach for establishing donor-specific allograft acceptance in adult recipients.