tacrolimus and Neointima

Post-operative complications of vascular anastomosis procedures remain a significant clinical challenge and health burden globally. Each year, millions of anastomosis procedures connect arteries and/or veins in vascular bypass, vascular access, organ transplant, and reconstructive surgeries, generally via suturing. Dysfunction of these anastomoses, primarily due to neointimal hyperplasia and the resulting narrowing of the vessel lumen, results in failure rates of up to 50% and billions of dollars in costs to the healthcare system. Non-absorbable sutures are the gold standard for vessel anastomosis; however, damage from the surgical procedure and closure itself causes an inflammatory cascade that leads to neointimal hyperplasia at the anastomosis site. Here, we demonstrate the development of a novel, scalable manufacturing system for fabrication of high strength sutures with nanofiber-based coatings composed of generally regarded as safe (GRAS) polymers and either sirolimus, tacrolimus, everolimus, or pimecrolimus. These sutures provided sufficient tensile strength for maintenance of the vascular anastomosis and sustained drug delivery at the site of the anastomosis. Tacrolimus-eluting sutures provided a significant reduction in neointimal hyperplasia in rats over a period of 14 days with similar vessel endothelialization in comparison to conventional nylon sutures. In contrast, systemically delivered tacrolimus caused significant weight loss and mortality due to toxicity. Thus, drug-eluting sutures provide a promising platform to improve the outcomes of vascular interventions without modifying the clinical workflow and without the risks associated with systemic drug delivery.

Topics: Animals; Hyperplasia; Nanofibers; Neointima; Rats; Sutures; Tacrolimus

Neointimal hyperplasia (NIH) remains one of the leading causes of graft failure after vascular anastomoses. Cytotoxic drugs, such as rapamycin and tacrolimus, have been shown to inhibit the development of NIH. In this study, the aim was to test the impact of a sustained releasing tacrolimus-chitosan-eluting suture on the development of NIH in a rat model.. In vitro tacrolimus release tests for a 7/0 tacrolimus-chitosan coated PVDF suture were confirmed for 1 month without an initial burst release. Endothelialisation over the aortotomy line occurred in both groups. The area of neointima was significantly reduced in group T compared with group C (ratio 0.22 ± 0.12 vs. 0.42 ± 0.11; p = .017) 1 month post-operatively. Likewise, the percentage of PCNA immunostaining significantly decreased in group C compared with group T (3.83 ± 2.85% vs. 11.17 ± 7.78%; p = .026). The cells constituting NIH were positive for ASMA immunostaining.. Tacrolimus-chitosan-eluting suture is shown to be an effective way to reduce NIH without interfering with normal endothelialisation.

Topics: Actins; Animals; Aorta; Cardiovascular Agents; Coated Materials, Biocompatible; Equipment Design; Hyperplasia; Male; Neointima; Proliferating Cell Nuclear Antigen; Rats, Wistar; Solubility; Suture Techniques; Sutures; Tacrolimus; Time Factors

Topics: Animals; Drug-Eluting Stents; Hyperplasia; Immunosuppressive Agents; Neointima; Rats; Sutures; Tacrolimus; Tunica Intima

Dysfunctional bone morphogenetic protein receptor-2 (BMPR2) signaling is implicated in the pathogenesis of pulmonary arterial hypertension (PAH). We used a transcriptional high-throughput luciferase reporter assay to screen 3,756 FDA-approved drugs and bioactive compounds for induction of BMPR2 signaling. The best response was achieved with FK506 (tacrolimus), via a dual mechanism of action as a calcineurin inhibitor that also binds FK-binding protein-12 (FKBP12), a repressor of BMP signaling. FK506 released FKBP12 from type I receptors activin receptor-like kinase 1 (ALK1), ALK2, and ALK3 and activated downstream SMAD1/5 and MAPK signaling and ID1 gene regulation in a manner superior to the calcineurin inhibitor cyclosporine and the FKBP12 ligand rapamycin. In pulmonary artery endothelial cells (ECs) from patients with idiopathic PAH, low-dose FK506 reversed dysfunctional BMPR2 signaling. In mice with conditional Bmpr2 deletion in ECs, low-dose FK506 prevented exaggerated chronic hypoxic PAH associated with induction of EC targets of BMP signaling, such as apelin. Low-dose FK506 also reversed severe PAH in rats with medial hypertrophy following monocrotaline and in rats with neointima formation following VEGF receptor blockade and chronic hypoxia. Our studies indicate that low-dose FK506 could be useful in the treatment of PAH.

Topics: Animals; Apoptosis; Bone Morphogenetic Protein 4; Bone Morphogenetic Protein Receptors, Type II; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Endothelial Cells; Endothelium, Vascular; High-Throughput Screening Assays; Humans; Hypertension, Pulmonary; Inhibitor of Differentiation Protein 1; Male; Mice; Mice, Knockout; Microvessels; Neointima; Pulmonary Artery; Rats; Rats, Sprague-Dawley; Signal Transduction; Smad Proteins; Tacrolimus; Tacrolimus Binding Protein 1A

We investigated whether tacrolimus (FK506) can inhibit neointimal formation in arterialised vein grafts in rats.. Lewis iliolumbar veins were implanted into the abdominal aorta of isogeneic rats. Animals in the treatment groups had daily intramuscular injections of tacrolimus at 0.2 mg/kg (group B) and 0.1 mg/kg (Group C), respectively. The control group A had no treatment. Light microscope evaluations of arterialised vein grafts were performed 30 days after operation. We determined the presence of endothelial cells, the thickness of intima and media, and the degree of infiltration by MHC class II positive, CD4 positive, and CD8 positive cells into the adventitia.. The intimal thickness in group B (5.0±1.0 µm) was statistically lower (P < 0.05) when compared to group C (7.0±3.0 µm). The intimal thickness in untreated group A (12.7±7.0 µm) was statistically higher (P < 0.01) when compared to both treated groups B and C, respectively. The medial thickness and degree of adventitial infiltration by MHC class II positive, CD8 positive, and CD4 positive cells did not differ between groups.. Treatment with tacrolimus (FK506) showed a dose dependant inhibition of neointimal hyperplasia in arterialised vein grafts in rats (Tab. 1, Fig. 3, Ref. 22).

Topics: Animals; Aorta, Abdominal; Hyperplasia; Immunosuppressive Agents; Male; Neointima; Rats; Rats, Inbred Lew; Tacrolimus; Tunica Intima; Veins

To measure serum cholesterol and triglyceride levels and NPC1L1 mRNA and protein as an index of cholesterol absorption during the development of chronic rejection (CR) in a rat model of intestinal transplantation.. Rats were randomly divided into two groups: Group 1 (n=20) underwent syngenic Lewis-to-Lewis transplantation and Group 2 (n=20) underwent allogenic F344-to-Lewis transplantation as well as treatment with FK506. Blood samples and intestinal tissue were procured on the 190th day after operation. Histological changes were analyzed and the semiquantitative scores of histological parameters were compared. The serum levels of cholesterol and triglyceride were determined. The expression of Niemann-Pick C1 Like 1(NPC1L1) mRNA and protein were analyzed by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and immunohistochemistry, respectively.. All the animals survived for the 190 days. The appearance and histology of isografts were almost normal whereas the allografts displayed thickened bowel wall and mesenteric fibrosis, concentric intimal thickening and interstitial fibrosis and inflammatory infiltration. The histology scores displayed a significant difference between the allografts and isografts (P < 0.001). No differences were observed for triglycerides for the two groups. The serum cholesterol levels increased significantly in the allogenic group in comparison with the syngenic group (P=0.034), while no difference was observed for triglyceride levels between groups. RT-PCR showed that the expression of NPC1L1 of allografts increased significantly (P=0.004). Immunohistochemistry confirmed RT-PCR findings.. Neointima formation and mesenteric fibrosis were the dominant pathological features. The increased expression of NPC1L1 might contribute to hypercholesterolemia, which may be involved in the pathogenesis of transplant arteriosclerosis.

Topics: Animals; Cholesterol; Graft Rejection; Immunohistochemistry; Intestines; Male; Membrane Transport Proteins; Neointima; Random Allocation; Rats; Rats, Inbred F344; Reverse Transcriptase Polymerase Chain Reaction; Tacrolimus; Transplantation, Isogeneic; Triglycerides

Topics: Animals; Femoral Artery; Hyperplasia; Immunosuppressive Agents; Neointima; Suture Techniques; Sutures; Swine; Tacrolimus