2005 Dr. Gary J. Becker Young Investigator Award: Periprocedural Oral Administration of the Leflunomide Analogue FK778 Inhibits Neointima Formation in a Double-injury Rat Model of Restenosis

Suppressed wound healing in a patient with rheumatoid arthritis taking leflunomide (arava)

Although patients with rheumatoid arthritis taking disease-modifying antirheumatic drugs (DMARDs) are monitored for various medication adverse events, DMARDs, and leflunomide in particular, have effects that are not observed clinically, specifically adverse effects on wound healing.

Suppressed wound healing in a patient with rheumatoid arthritis taking leflunomide (arava)

Although patients with rheumatoid arthritis taking disease-modifying antirheumatic drugs (DMARDs) are monitored for various medication adverse events, DMARDs, and leflunomide in particular, have effects that are not observed clinically, specifically adverse effects on wound healing.

The new immunosuppressive agent FK778 attenuates neointima formation in an experimental venous bypass graft model

Neointima formation as a result of smooth muscle cell (SMC) proliferation still contributes significantly to venous bypass graft stenosis and failure. The new immunosuppressive agent FK778 has recently been shown to exert anti-proliferative effects. We examined the inhibitory potential of FK778 on venous SMC proliferation and neointima formation in an experimental venous bypass graft model. Quiescent venous SMCs were incubated for 48 h with 10% FCS and different concentrations of FK778. SMC proliferation was measured by Ki67 immunostaining. Uridine was added to reverse FK778 induced pyrimidine synthesis blockade. The effect of FK778 treatment on neointima formation in vivo was assessed in an autologous epigastric vein-to femoral artery interposition graft model in rats. In vitro, FK778 inhibited venous SMC proliferation in a dose dependent manner. This effect was reversed by addition of uridine. In vivo, 3-week oral treatment with FK778 (15 mg/kg/d) significantly reduced neointima formation and stenosis in venous bypass grafts. We show that the immunosuppressive agent FK778 can prevent neointima formation in experimental venous bypass grafts by inhibiting venous SMC proliferation. FK778 might provide a new pharmacological therapy to limit vein graft stenosis and bypass graft failure.

Leflunomide prevents vasospasm secondary to subarachnoid haemorrhage

BACKGROUND

Though cerebral vasospasm is one of the most serious complications of subarachnoid haemorrhage (SAH), its complex pathogenesis is poorly understood and available clinical treatment options are unsatisfactory. This study was designed to examine the efficacy of leflunomide, an immunomodulatory agent with inhibitory properties, on vascular smooth muscle cell proliferation and inflammation in a rabbit cerebral vasospasm model.

METHODS

Twenty-two adult New-Zealand rabbits were assigned to 4 groups: control, SAH, SAH plus vehicle, SAH plus leflunomide. Subarachnoid haemorrhage was induced by administration of 1 ml of fresh unheparinised autologous arterial blood into the cisterna magna. Oral leflunomide (2 mg/kg) or vehicle treatment was started 12 h after the induction of subarachnoid haemorrhage and administered once a day. Three days later, the animals were sacrificed and the basilar artery was examined histologically for the lumen area and the thickness of the vessel wall. Inflammatory reaction was also examined by counting white blood cells within the vessel wall by means of light microscopic examination using haematoxylin and eosin staining.

FINDINGS

Severe and moderate vasospasms were detected in the basilar artery of the SAH and SAH plus vehicle treated groups, respectively. Leflunomide effectively reduced the vasospasm of the basilar artery. Compared to the vehicle treated group, leflunomide significantly reduced the lumen area (p < 0.01) and hyperplasia of the vessel wall (p < 0.01). Although inflammatory response within the vessel wall was reduced in the leflunomide treated group, no statistical significance was found between groups (p = 0.07).

CONCLUSION

This study demonstrates for the first time that leflunomide treatment attenuates cerebral vasospasm in a rabbit SAH model while inflammatory reaction in the vessel wall is not affected. Although further studies are needed to reveal its molecular mechanisms in relieving vasospasm, leflunomide may provide a therapeutic potential for human cerebral vasospasm induced by SAH.

Is the Malononitrilamide FK778 Better for the Prevention of Acute or Chronic Rejection?

OBJECTIVE

The aim of this study was to assess the efficacy of FK778 to prevent acute and chronic allograft rejection compared with other immunosuppressive agents.

MATERIALS AND METHODS

Heterotopic Brown-Norway (BN)-to-Lewis rat cardiac transplantations and heterotopic BN-to-Lewis tracheal transplantations were performed to study acute heart rejection and the development of chronic obliterative airway disease (OAD), respectively. Recipients were treated with FK778, tacrolimus, MMF, or sirolimus for 10 days (acute rejection study) or 28 days (chronic OAD study) at varying doses.

RESULTS

In untreated recipients, cardiac allograft survival was 6.2 +/- 0.4 days. FK778 (20 mg/kg), tacrolimus (2 or 8 mg/kg), mycophenolate mofetil (MMF; 40 mg/kg), or sirolimus (0.5 or 2 mg/kg) significantly prolonged graft survival to 17.0 +/- 2.8, 18.5 +/- 2.7, 25.0 +/- 2.5, 20.7 +/- 3.8, 14.5 +/- 2.2, and 23.2 +/- 1.5 days, respectively (P < .05). Tracheal grafts in untreated recipients showed intense infiltration and complete luminal obliteration by day 28. FK778 (20 mg/kg), tacrolimus (1 or 4 mg/kg), MMF (10 or 40 mg/kg), or sirolimus (0.5 or 2 mg/kg) significantly inhibited tracheal luminal obliteration (19.5% +/- 16.4%, 44.2% +/- 33.6%, 12.3% +/- 3.3%, 61.7% +/- 18.6%, 18.3% +/- 11.3%, 55.0% +/- 30.9%, and 8.5% +/- 3.5% (P < .05). All 4 high-dose groups showed similar efficacy.

CONCLUSIONS

When used in therapeutic doses, tacrolimus and sirolimus were more effective than FK778 to prolong cardiac allograft survival. However, with its antiproliferative effects on smooth muscle cells, its good tolerability, and its blockade of cytomegalovirus replication, FK778 proved effective to prevent chronic OAD development. Thus, FK778 may acquire an important role in maintenance therapy for the prevention of long-term fibroproliferative complications.