A comparison of the sensitivity of pig and human peripheral blood mononuclear cells to the antiproliferative effects of traditional and newer immunosuppressive agents

Immunosuppressive regimens in porcine transplantation models

Pigs, or Sus scrofa domestica, are commonly used animal models in translational transplantation research due to their anatomical, physiological, and immunological similarities to humans. In solid organ transplantation studies, immunosuppressive medications may be administered to pigs to prevent rejection. We provide an overview of the immunosuppressive regimens used in allogeneic solid organ transplantation in pigs, including heart, lung, kidney, bowel and cotransplanted organs and focus on the use of tacrolimus, mycophenolate mofetil, and corticosteroids.

Herbal therapy: A review of emerging pharmacological tools in the management of diabetes mellitus in Africa

BACKGROUND

Diabetes mellitus is a chronic physiological glucose metabolic disorder. It has affected millions of people all over the world thereby having a significant impact on quality of life. The management of diabetes includes both nonpharmacological and conventional interventions. Drawbacks in conventional therapy have led to seeking alternative therapy in herbal medicine. Therefore, the need to review, elucidate and classify their mode of action in therapy for diabetes disease arises.

MATERIALS AND METHODS

Comprehensive literature reports were used to review all conventional agents and herbal therapy used in the management of diabetes. An online database search was conducted for medicinal plants of African origin that have been investigated for their antidiabetic therapeutic potentials.

RESULTS

The results showed that of the documented sixty five plants used, fourteen inhibit intestinal absorption of glucose, three exhibit insulin-mimetic properties, seventeen stimulate insulin secretion from pancreatic beta cells, twelve enhance peripheral glucose uptake, one promotes regeneration of beta-cell of islets of Langerhans, thirteen ameliorate oxidative stress and twenty induces hypoglycemic effect (mode of action is still obscure). Thirteen of these plants have a duplicate mode of actions while one of them has three modes of actions. These agents have a similar mechanism of action as the conventional drugs.

CONCLUSION

In conclusion, antidiabetic activities of these plants are well established; however, the molecular modulation remains unknown. It is envisaged that the use of herbal therapy will promote good health and improve the status of diabetic patients.

Optimal dosing and duration of oral everolimus to inhibit in-stent neointimal growth in rabbit iliac arteries

BACKGROUND

Everolimus is an orally active derivative of sirolimus. Oral administration of rapamycin is efficacious in the reduction of neointima formation and clinical restenosis; however, its optimal dose and duration have not been determined.

METHODS

New Zealand White rabbits were divided into three groups. The first (low-dose) group received 1.5 mg/kg everolimus 1 day before stenting, followed by 0.75 mg/kg/day everolimus for 28 days. The second (high-dose) group received 6 mg/kg everolimus 1 day before, on the day of, and on the day after stenting, followed by 2 mg/kg/day for 4 days. The third (placebo) group received a matching volume of vehicle similar to that of Group 2. Twenty-eight days after stenting, animals were euthanized and morphometry was performed.

RESULTS

In the high-dose group, circulating everolimus levels corresponded with administrated dose levels; by Day 12, no circulating everolimus could be detected. In the low-dose everolimus group, levels remained constant up to 28 days. When compared with placebo, low-dose everolimus was associated with a significant reduction in medial thickness (32%), neointimal area (60%), and percent stent stenosis (33%); however, high-dose everolimus had no significant effect.

CONCLUSIONS

In conclusion, oral everolimus suppresses in-stent neointimal growth in rabbit iliac arteries. Four weeks of low-dose everolimus is more effective than 7 days of high-dose everolimus.

Conversion to Sirolimus and Mycophenolate Can Attenuate the Progression of Bronchiolitis Obliterans Syndrome and Improves Renal Function after Lung Transplantation

BACKGROUND

Bronchiolitis obliterans syndrome (BOS) is the major problem after lung and heart-lung transplantation (LTx/HLTx). Sirolimus (Sir) and Mycophenolate (MMF) showed a promising efficacy in the treatment of BOS in animal models. The first clinical experience in converting LTx/HLTx-recipients with BOS from calcineurin inhibitor-(CNI)-based immunosuppression to a Sir-MMF based immunosuppression is reported herein.

METHODS

Six LTx- and five HLTx-recipients (eight men; 0.9 to 8 years after transplantation) with CNI-based immunosuppression (plus MMF) in whom BOS was diagnosed were included in the study. Mean patient age was 37+/-13 years (range 17-62 years). Sir was started with 6 mg and continued adjusted to according target trough levels (8-14 ng/ml). Subsequently, the CNIs were tapered down and finally stopped. Follow up included self determined pulmonary function tests, microbiological screening, chest radiographs, and laboratory studies

RESULTS

Two acute rejection episodes occurred during the study period. The incidence of infection was 2.2+/-1.3 infections/patient-year after conversion. Mean FEV1 decreased after a mean follow up of 14.8+/-1.4 months: from 2.1+/-0.7 l prior conversion to 1.3+/-0.6l after conversion (P=0.03). However, graft function remained stable in three patients and progression of BOS slowed down in three patients. Overall, 2 of 10 patients died due to ongoing BOS while awaiting retransplantation

CONCLUSIONS

After BOS was diagnosed, conversion to MMF and Sir stabilized graft function only in some of the converted patients. Therefore, earlier administration of Sir-based immunosuppression might be a more promising approach. Whether conversion to CNI-free immunosuppression can actually ameliorate the extent or progression of BOS has to be investigated in randomized trials.

Long-term effects of novel biolimus eluting DEVAX AXXESS plus nitinol self-expanding stent in a porcine coronary model

OBJECTIVE

The purpose of this study was to evaluate the long-term effects of the DEVAX AXXESS biolimus eluting stent (BES) in a porcine coronary model, compared with those of bare metal stent (BMS) and polymer only stent (POS) controls.

BACKGROUND

Excessive neointimal growth has been identified as a major cause of late failure of percutaneous coronary interventions. The effect of drug eluting from self-expanding stents for prevention of neointimal hyperplasia has not been studied before. The DEVAX AXXESS is a self-expanding nickel titanium stent, coated with antiproliferative compound-biolimus.

METHODS

Twenty juvenile farm swine, 25-35 kg in weight, 3-6 months in age were used. Each animal received a stent to the left anterior descending artery, left circumflex or right coronary arteries as permitted per anatomy. The chronic vascular response after BES implantation was compared with that after BMS and POS implantation at 28, 90, and 180 days follow-up.

RESULTS

The 28-day outcome by quantitative coronary angiography (QCA) showed significant increase in minimal luminal diameter (MLD) in the BES (MLD: 2.90 +/- 0.97, 2.39 +/- 0.90, 1.59 +/- 0.91; P = 0.009) compared with BMS and POS, respectively. By histomorphometric analysis, there was also a corresponding significant reduction in neointimal tissue proliferation in the BES (average neointimal area: 2.78 +/- 0.07, 5.46 +/- 0.66, 8.42 +/- 0.85; P = 0.002) compared with that in BMS and POS controls, respectively at 28-days follow-up. At 90 and 180 days, the mean neointimal area was not significantly different between the BES and the controls.

CONCLUSIONS

BES favorably modulates the neointimal tissue formation for 28 days, in the porcine coronary model. Long-term inhibition of neointimal hyperplasia is not sustained most likely because of the delayed cellular proliferation and inflammation in the vessel wall.

Evaluation of four-year coronary artery response after sirolimus-eluting stent implantation using serial quantitative intravascular ultrasound and computer-assisted grayscale value analysis for plaque composition in event-free patients

OBJECTIVES

This study sought to evaluate the long-term arterial response after sirolimus-eluting stent implantation.

BACKGROUND

Sirolimus-eluting stents are effective in inhibiting neointimal hyperplasia without affecting plaque volume behind the stent struts at six months.

METHODS

Serial quantitative intravascular ultrasound and computer-assisted grayscale value analysis over four years were performed in 23 event-free patients treated with sirolimus-eluting stents.

RESULTS

In the first two years, the mean plaque volume (155.5 +/- 42.8 mm3 post-procedure and 156.8 +/- 57.7 mm3 at two years, p = 0.86) and plaque compositional change expressed as mean percent hypoechogenic tissue of the plaque behind the stent struts (78.9 +/- 8.6% post-procedure and 78.2 +/- 8.9% at two years, p = 0.67) did not significantly change. However, significant plaque shrinking (change in plaque volume = -18.4 mm3, p = 0.02) with an increase in plaque echogenicity (change in percent hypoechogenic tissue = -7.8%, p < 0.0001) was observed between two and four years. The mean neointimal volume increased over four years from 0 to 8.4 +/- 5.8 mm3 (p < 0.0001). However, no further statistically significant change occurred between two and four years (7.0 +/- 6.7 mm3 vs. 8.4 +/- 5.8 mm3, p = 0.25).

CONCLUSIONS

Between two and four years after sirolimus-eluting stent implantation, peri-stent tissue shrank with a concomitant increase in echogenicity. These intravascular ultrasound findings suggest that late chronic artery responses may evolve for up to four years after sirolimus-eluting stent implantation. In addition, the fact that the neointima does not significantly change from two to four years may suggest that the biological phenomenon of a delayed healing response has begun to subside.

Dose-dependent inhibition of myointimal hyperplasia by orally administered rapamycin

Myointimal hyperplasia (MIH) after vascular intervention is a major problem. Recent reports describing elimination of within-stent restenosis by means of rapamycin-eluting stents prompted us to examine the effect of systemic oral rapamycin on MIH induced by arterial trauma. We studied the effect of oral rapamycin on MIH after rabbit aorta balloon injury. Thirty-five New Zealand white rabbits (2.5-3 kg) had aortic injury and were given either no rapamycin (control), 0.1 (low dose) rapamycin mg/kg/day, or 0.4 mg/kg/day (high dose). Rapamycin was started 1 week before injury and continued for 3 (4 weeks total) or 6 weeks (7 weeks total) post-injury. Sections were analyzed to measure aortic intima/media area ratios (I:M) at either 3 or 6 weeks. At 3 weeks, the I:M (mean +/- SD) for controls was 0.53 +/- 0.1; for low dose, 0.17 +/- 0.13; and for high dose, 0.24 +/- 0.07 (p < 0.001 vs. control). At 6 weeks, the I:M for controls was 0.52 +/- 0.12; for low dose-4 weeks, 0.29 +/- 0.15; low dose-7 weeks, 0.33 +/- 0.07; and high dose-4 weeks, 0.47 +/- 0.16. At 6 weeks only the difference between the low dose-4 weeks and control I:M ratios was significant (p = 0.018). The results confirm earlier studies showing that systemic rapamycin inhibits MIH after arterial injury when drug therapy is started before injury. Therapy for 3 or 6 weeks after injury yields similar inhibition, indicating that exposure to the drug early in the response to injury is more important than prolonged exposure. We observed a paradoxical relation between dose and degree of MIH inhibition, with the low dose being more effective than the high dose at both time intervals studied. Overall, the results suggest that oral rapamycin therapy might be a useful adjunct to clinical interventions at risk for development of MIH.

Auxiliary en-bloc liver-small bowel transplantation with partial pancreas preservation in pigs

AIM

The aim of this study was to describe an auxiliary combined liver-small bowel transplantation model with the preservation of duodenum, head of pancreas and hepatic biliary system in pigs. The technique, feasibility, security and immunosuppression were commented.

METHODS

Forty outbred long-white pigs were randomized into two groups, and the auxiliary composite liver/small bowel allotransplantations were undertaken in 10 long-white pigs in each group with the recipient liver preserved. Group A was not treated with immunosuppressive drugs while group B was treated with cyclosporine A and methylprednisolone after operation. The hemodynamic changes and amylase of body fluid (including blood, urine and abdominal drain) were analyzed.

RESULTS

The average survival time of the animals was 10+/-1.929 d (6 to 25 d) in group A while more than 30 d in group B. The pigs could tolerate the hemodynamic fluctuation during operation and the hemodynamic parameters recovered to normal 2 h after blood reperfusion. The transient high amylase level was decreased to normal one week after operation and autopsy showed no pancreatitis.

CONCLUSION

Auxiliary en-bloc liver-small bowel transplantation with partial pancreas preservation is a feasible and safe model with simplified surgical techniques for composite liver/small bowel transplantation. This model may be used as a preclinical training model for clinical transplantation method, clinical liver-small bowel transplantation related complication research, basic research including immunosuppressive treatment, organ preservation, acute rejection, chronic rejection, immuno-tolerance and xenotransplantation.

Inhibition of cytokine production by the traditional oriental medicine, 'Gamcho-Sasim-Tang' in mitogen-stimulated peripheral blood mononuclear cells from Adamantiades-Behçet's patients

Gamcho-Sasim-Tang (GS-Tang) is a traditional Chinese medication, which has been successfully used in Korea for the treatment of Adamantiades-Behçet's disease (ABD). We investigated the modulation effects of GS-Tang on cytokine production from phytohaemagglutinin-stimulated peripheral blood mononuclear cells of Behçet's patients. ABD is a systemic inflammatory disorder and might involve immune dysfunction. Cytokines involved in the regulation of inflammatory reactions and immune responses may play a role in the pathogenesis of ABD. GS-Tang (1 mg/ml) significantly inhibited the production of proinflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta), compared to absence of GS-Tang (by 42.0+/-6.6% inhibition for TNF-alpha and 95.9+/-5.7% for IL-1 beta, P<0.05). GS-Tang also inhibited the production of IFN-gamma, immunoregulatory T helper cell type 1 cytokine, by 80.2+/-5.3% (P=0.001). The inhibitory effects of GS-Tang on cytokine production showed dose-dependent manner. Our results suggest that GS-Tang might have anti-inflammatory and immuno-regulatory effects through the cytokine modulation.

Coexpression of CD4 and CD8alpha on rat T-cells in whole blood: a sensitive marker for monitoring T-cell immunosuppressive drugs

The aim of this study was to develop a new quantitative method for measuring in vitro the effects of T-cell immunosuppressive drugs by flow cytometry. Rat whole blood samples were stimulated with the T-cell mitogen succinylated concanavalin A in the presence or absence of different drugs. After 3 days, the expression of CD25 and CD8alpha in mitogen-stimulated CD4(+) cells increased 10- to 20-fold as measured by flow cytometry. Drug efficacy and potency was calculated based on dose-response curves of the drug-mediated decrease in CD4(+)/CD8alpha(+)/CD25(+) cells. The expression of CD8alpha in mitogen-stimulated CD4(+) cells was blocked completely by calcineurin inhibitors (cyclosporine A and FK-506), and partially by rapamycin and SDZ-RAD. The IC(50) (50% inhibitory concentration) values obtained were (mean+/-S.E.): 99.5+/-16.6 nM for cyclosporine A, 10.4+/-1.3 nM for FK-506, 1.8+/-0.7 nM for rapamycin, and 6.4+/-1.1 nM for SDZ-RAD. Our results show, for the first time, that CD8alpha, used as an activation antigen, is a sensitive marker for monitoring T-cell immunosuppression.

Hand transplantation: comparisons and observations of the first four clinical cases

Twenty, 15, and 8 months after the first four successful human hand transplant procedures were performed in Lyon (France), Louisville (U. S.), and Guangzhou (China), the transplant teams convened in Louisville, Kentucky, to share their experiences at the Second International Symposium on Composite Tissue Allotransplantation. This article presents reconstructive and immunological data from these landmark procedures in tabular format, in an attempt to answer some key questions about early outcomes of clinical hand transplantation. On the basis of these data, the initial outcomes of the first four hand transplants are encouraging and warrant proceeding with additional hand transplantations.