Search

With the ripening of 3D printing technology and the discovery of a variety of printable materials, 3D-printed vascular stents provide new treatment options for patients with angiocardiopathy. Bioresorbable stent not only combines the advantages of metallic stent and drug-coated balloon, but also avoids the disadvantages of them. 3D printing is also an economical and efficient way to produce stents and makes it possible to construct complex structures. In this study, stents made from poly(l-lactic acid) (PLLA), poly(ε-caprolactone) (PCL) and poly(l-lactide-co-caprolactone) (PLCL) were manufactured by 3D printing and evaluated for radial strength, crystallinity and molecular weight. PLCL copolymerized by different proportions of lactic acid and caprolactone showed different mechanical and degradation properties. This demonstrated the potential of 3D printing as a low-cost and high throughput method for stent manufacturing. The PLLA and PLCL 95/5 stents had similar mechanical properties, whereas PLCL 85/15 and PCL stents both had relatively low radial strength. In general, PLCL 95/5 had a faster degradation rate than PLLA. These two materials were made into peripheral vascular bioresorbable scaffolds (BRS) and further studied by additional bench testing. PLCL 95/5 peripheral BRS had superior mechanical properties in terms of flexural/bending fatigue and compression resistance.

PDF file - 74K, CEP-32496 Supplemental Data.

Background— Drug-coated balloons are rapidly emerging as a therapeutic alternative for the interventional treatment of peripheral vascular disease. The purpose of this study was to test the hypothesis that an angioplasty balloon coated with the mTOR inhibitor zotarolimus (ZCB) would inhibit neointimal hyperplasia in a novel injury-based superficial femoral artery model in the familial hypercholesterolemic swine. Methods and Results— A total of 44 familial hypercholesterolemic swine were included (12 designated to study tissue pharmacokinetics and 32 to study safety and efficacy). Fogarty balloon denudation was performed in all superficial femoral artery segments, followed by balloon angioplasty. In the pharmacokinetic study, a total of 24 ZCBs (300 μg/cm 2 ) were used. Zotarolimus was detected in arterial tissue at 5 minutes (162 ng/mg of tissue), 24 hours (5.9 ng/mg of tissue), and 28 days (0.007 ng/mg of tissue) after ZCB inflation. In the safety and efficacy study, superficial femoral artery segments were randomized to either high-dose (600 μg/cm 2 , n=16), low-dose (300 μg/cm 2 , n=16), or paired uncoated balloons (high-dose ZCB control, n=16; low-dose ZCB control, n=16). At 28 days, the percentage of angiographic stenosis was similar among all tested groups. Histological analysis demonstrated a reduction in neointimal formation in both ZCB groups compared with controls (high-dose ZCB 44% reduction, P =0.007; low-dose ZCB 22% reduction, P =0.08). There was no evidence of delayed arterial healing or vascular toxicity in any of the ZCB groups. Conclusions— The single delivery of zotarolimus via coated balloon is feasible, and therapeutic levels are maintained up to 28 days. The ZCB technology appears to be effective in the reduction of neointimal proliferation in the superficial femoral artery of the familial hypercholesterolemic swine.

For peripheral endovascular intervention, self-expanding (SE) stents are commonly oversized in relation to target arteries to assure optimal wall apposition and prevent migration. However, the consequences of oversizing have not been well studied. The purpose of this study was to examine the effects of SE stent oversizing (OS) with respect to the kinetics of late stent expansion and the long-term histological effects of OS. Pairs of overlapped 8 × 28-mm Nitinol SE stents were implanted into the iliofemoral arteries of 14 Yucatan swine. Due to variations in target artery size, the stent-to-artery ratio ranged from 1.2:1 to 1.9:1. Lumen and stent diameters were assessed by quantitative angiography at the time of implantation. Following angiographic assessment at 6 months, stented arteries were perfusion-fixed, sectioned, and stained for histological analysis. Immediately following implantation, the stents were found to be expanded to a range of 4.7–7.1 mm, largely conforming to the diameter of the recipient target artery. The stents continued to expand over time, however, and all stents had enlarged to nearly their 8-mm nominal diameter by 6 months. The histological effects of OS were profound, with marked increases in injury and luminal area stenosis, including a statistically significant linear correlation between stent-to-artery ratio and area stenosis. In this experimental model of peripheral endovascular intervention, oversized Nitinol SE stents are constrained by their target artery diameter upon implantation but expand to their nominal diameter within 6 months. Severe OS (stent-to-artery ratio >1.4:1) results in a profound long-term histological response including exuberant neointimal proliferation and luminal stenosis.

Idoxifene, a novel selective estrogen receptor modulator, was tested for its effects on bone loss, serum cholesterol, and uterine wet weight and histology in the ovariectomized (Ovx) rat. Idoxifene (0.5 mg/kg x day) completely prevented loss of both lumbar and proximal tibial bone mineral density (BMD). In an intervention study, idoxifene (0.5 and 2.5 mg/kg x day) completely prevented further loss of both lumbar and proximal tibial BMD during a 2-month treatment period commencing 1 month after surgery, when significant loss of BMD had occurred in the Ovx control group. Idoxifene reduced total serum cholesterol, which was maximal at 0.5 mg/kg x day. Idoxifene alone displayed minimal uterotrophic activity in Ovx rats and inhibited the agonist activity of estrogen in intact rats. Histologically, myometrial and endometrial atrophy were observed in both idoxifene and vehicle-treated Ovx rats. In this report, we also provide molecular-based evidence to support the observations in vivo of a novel selective estrogen receptor modulator (SERM) mechanism of action in bone and endometrial cells. Idoxifene is an agonist through the estrogen response element (ERE) and exhibits similar postreceptor effects to estrogen in bone-forming osteoblasts. Idoxifene also stimulates osteoclast apoptosis, and these pleiotropic effects ultimately could contribute to the maintenance of bone homeostasis. However, idoxifene differs from estrogen in a tissue-specific manner. In human endometrial cells, where estrogen is a potent agonist through the ERE, idoxifene has negligible agonist activity. Moreover, idoxifene was able to block estrogen induced gene expression in endometrial cells, which is in agreement with the observation in the intact rat study. In the uterus, idoxifene has a pharmacologically favorable profile, lacking agonist and therefore growth-promoting activity. Together with its cholesterol lowering effect and lack of uterotrophic activity, these data suggest that idoxifene may be effective in the prevention of osteoporosis and other postmenopausal diseases without producing unwanted estrogenic effects on the endometrium.

Objective. To evaluate the effect of SK&F 106615 on joint integrity in rats with adjuvant-induced arthritis (AIA). Methods. AIA was induced in Lewis rats on day 0, and the animals were treated either prophylactically (days 0–16 or days 0–23) or therapeutically (days 10–23) with SK&F 106615. Efficacy was determined by measurements of paw inflammation, bone mineral density (BMD) using dual x-ray absorptiometry, and magnetic resonance imaging (MRI). Joint integrity was also determined histologically, and serum interleukin-6 (IL-6) levels were measured as a marker of the antiinflammatory effects of the compound. Results. Prophylactic treatment (days 0–16) of AIA rats with SK&F 106615 significantly inhibited paw volume at doses of 5–45 mg/kg/day given orally on 5 days each week. Extensive evaluation of joint integrity in rats treated with SK&F 106615 20 mg/kg/day orally for 23 days showed inhibition of paw volume, normalization of BMD, and significant improvement in disease by MRI and histologic assessment compared with the AIA controls. Elevated levels of serum IL-6 in AIA rats were reduced dramatically by SK&F 106615. Therapeutic treatment (days 10–23) resulted in similar protective effects measured by paw inflammation, BMD, and MRI. In the therapeutic protocol, serum IL-6 appeared to be a more sensitive marker of antiinflammatory activity than paw edema. Conclusion. Symptoms of AIA in rats are significantly reduced by prophylactic and therapeutic treatment with SK&F 106615. Of particular note, this compound appears to exert a protective effect on joint integrity and to have disease-modifying properties.

Mutations in the BRAF gene have been identified in approximately 7% of cancers, including 60% to 70% of melanomas, 29% to 83% of papillary thyroid carcinomas, 4% to 16% colorectal cancers, and a lesser extent in serous ovarian and non–small cell lung cancers. The V600E mutation is found in the vast majority of cases and is an activating mutation, conferring transforming and immortalization potential to cells. CEP-32496 is a potent BRAF inhibitor in an in vitro binding assay for mutated BRAFV600E (Kd BRAFV600E = 14 nmol/L) and in a mitogen-activated protein (MAP)/extracellular signal–regulated (ER) kinase (MEK) phosphorylation (pMEK) inhibition assay in human melanoma (A375) and colorectal cancer (Colo-205) cell lines (IC50 = 78 and 60 nmol/L). In vitro, CEP-32496 has multikinase binding activity at other cancer targets of interest; however, it exhibits selective cellular cytotoxicity for BRAFV600E versus wild-type cells. CEP-32496 is orally bioavailable in multiple preclinical species (>95% in rats, dogs, and monkeys) and has single oral dose pharmacodynamic inhibition (10–55 mg/kg) of both pMEK and pERK in BRAFV600E colon carcinoma xenografts in nude mice. Sustained tumor stasis and regressions are observed with oral administration (30–100 mg/kg twice daily) against BRAFV600E melanoma and colon carcinoma xenografts, with no adverse effects. Little or no epithelial hyperplasia was observed in rodents and primates with prolonged oral administration and sustained exposure. CEP-32496 benchmarks favorably with respect to other kinase inhibitors, including RAF-265 (phase I), sorafenib, (approved), and vemurafenib (PLX4032/RG7204, approved). CEP-32496 represents a novel and pharmacologically active BRAF inhibitor with a favorable side effect profile currently in clinical development. Mol Cancer Ther; 11(4); 930–41. ©2012 AACR.

A substantial body of evidence supports the utility of antiangiogenesis inhibitors as a strategy to block or attenuate tumor-induced angiogenesis and inhibition of primary and metastatic tumor growth in a variety of solid and hematopoietic tumors. Given the requirement of tumors for different cytokine and growth factors at distinct stages of their growth and dissemination, optimal antiangiogenic therapy necessitates inhibition of multiple, complementary, and nonredundant angiogenic targets. 11-(2-Methylpropyl)-12,13-dihydro-2-methyl-8-(pyrimidin-2-ylamino)-4H-indazolo[5,4-a]pyrrolo[3,4-c]carbazol-4-one (11b, CEP-11981) is a potent orally active inhibitor of multiple targets (TIE-2, VEGF-R1, 2, and 3, and FGF-R1) having essential and nonredundant roles in tumor angiogenesis and vascular maintenance. Outlined in this article are the design strategy, synthesis, and biochemical and pharmacological profile for 11b, which completed Phase I clinical assessing safety and pharmacokinetics allowing for the initiation of proof of concept studies.

Modulating protein ubiquitination via proteasome inhibition represents a promising target for cancer therapy, because of the higher sensitivity of cancer cells to the cytotoxic effects of proteasome inhibition. Here we show that CEP-18770 is a novel orally-active inhibitor of the chymotrypsin-like activity of the proteasome that down-modulates the nuclear factor-κB (NF-κB) activity and the expression of several NF-κB downstream effectors. CEP-18770 induces apoptotic cell death in multiple myeloma (MM) cell lines and in primary purified CD138-positive explant cultures from untreated and bortezomib-treated MM patients. In vitro, CEP-18770 has a strong antiangiogenic activity and potently represses RANKL–induced osteoclastogenesis. Importantly, CEP-18770 exhibits a favorable cytotoxicity profile toward normal human epithelial cells, bone marrow progenitors, and bone marrow–derived stromal cells. Intravenous and oral administration of CEP-18770 resulted in a more sustained pharmacodynamic inhibition of proteasome activity in tumors relative to normal tissues, complete tumor regression of MM xenografts and improved overall median survival in a systemic model of human MM. Collectively, these findings provide evidence for the utility of CEP-18770 as a novel orally active proteasome inhibitor with a favorable tumor selectivity profile for the treatment of MM and other malignancies responsive to proteasome inhibition.

CEP-7055, a fully synthetic, orally active N,N-dimethylglycine ester of CEP-5214, a C3-(isopropylmethoxy)–fused pyrrolocarbazole with potent pan–vascular endothelial growth factor receptor (VEGFR) kinase inhibitory activity, has recently completed phase I clinical trials in cancer patients. These studies evaluated the antitumor efficacy of CEP-7055 using orthotopic models of glioblastoma and colon carcinoma in combination with temozolomide, and irinotecan and oxaliplatin, respectively, for their effects on primary and metastatic tumor burden and median survival. Chronic administration of CEP-7055 (23.8 mg/kg/dose) and temozolomide resulted in improvement of median survival of nude mice bearing orthotopic human glioblastoma xenografts compared with temozolomide alone (261 versus 192 days, respectively; P ≤ 0.02). Reductions in neurologic dysfunction, brain edema, hemorrhage, and intratumoral microvessel density (CD34 staining) were observed in glioma-bearing mice receiving CEP-7055 alone, temozolomide alone, and the combination of CEP-7055 and temozolomide relative to vehicle and to temozolomide monotherapy. The administration of CEP-7055 in combination with irinotecan (20 mg/kg/dose i.p. × 5 days), and to a lesser degree with oxaliplatin (10 mg/kg/dose i.v.), showed reductions on primary colon carcinoma and hepatic metastatic burden in the CT-26 tumor model relative to that achieved by irinotecan and oxaliplatin monotherapy. These data show the significant efficacy and tolerability of optimal efficacious doses of CEP-7055 when given in combination with temozolomide and irinotecan relative to monotherapy with these cytotoxic agents in preclinical orthotopic glioma and colon carcinoma models and lend support for the use of these treatment regimens in a clinical setting in patients with glioblastoma and colon carcinoma. [Mol Cancer Ther 2006;5(7):1744–53]

Tumor-associated angiogenesis is critical for tumor growth and metastasis and is controlled by various pro- and antiangiogenic factors. The Eph family of receptor tyrosine kinases has emerged as one of the pivotal regulators of angiogenesis. Here we report that interfering with EphA signaling resulted in a pronounced inhibition of angiogenesis in ex vivo and in vivo model systems. Administration of EphA2/Fc soluble receptors inhibited, in a dose-dependent manner, microvessel formation in rat aortic ring assay, with inhibition reaching 76% at the highest dose of 5000 ng/ml. These results were further confirmed in vivo in a porcine aortic endothelial cell-vascular endothelial growth factor (VEGF)/basic fibroblast growth factor Matrigel plug assay, in which administration of EphA2/Fc soluble receptors resulted in 81% inhibition of neovascularization. The additive effects of simultaneous inhibition of VEGF receptor 2 and EphA signaling pathways in aortic ring assay and antiangiogenic efficacy of EphA2/Fc soluble receptors against VEGF/basic fibroblast growth factor-mediated neovascularization in vivo indicated a critical and nonredundant role for EphA signaling in angiogenesis. Furthermore, in two independent experiments, we demonstrated that EphA2/Fc soluble receptors strongly (by ∼50% versus controls) suppressed growth of ASPC-1 human pancreatic tumor s.c. xenografts. Inhibition of tumor growth was due to decreased proliferation of tumor cells. In an orthotopic pancreatic ductal adenocarcinoma model in mice, suppression of EphA signaling by i.p. administration of EphA2/Fc (30 μg/dose, three times a week for 56 days) profoundly inhibited the growth of primary tumors and the development of peritoneal, lymphatic, and hepatic metastases. These data demonstrate a critical role of EphA signaling in tumor growth and metastasis and provide a strong rationale for targeting EphA2 receptors for anticancer therapies.

Poly(ADP-ribose) polymerase 1 (PARP-1) is a nuclear zinc finger DNA-binding protein that is implicated in the repair of DNA damage. Inhibition of PARP-1 through genetic knockouts causes cells to become hypersensitive to various chemotherapeutic agents. We tested the chemopotentiating ability of the PARP-1 inhibitor, CEP-6800, when used in combination with temozolomide (TMZ), irinotecan (camptothecin or SN38), and cisplatin against U251MG glioblastoma, HT29 colon carcinoma, and Calu-6 non-small cell lung carcinoma xenografts and cell lines, respectively. Exposure of tumor cells to TMZ, camptothecin (or SN38), and cisplatin before, or in the presence of, CEP-6800 significantly increased the onset and the magnitude of DNA damage, the duration for cells to effect repair, and the onset, duration, or fraction of cells arrested at the G(2)/M boundary. In addition, in vivo biochemical efficacy studies with CEP-6800 showed that it was able to attenuate irinotecan- and TMZ-induced poly(ADP-ribose) accumulation in LoVo and HT29 xenografts, respectively. Treatment of CEP 6800 (30 mg/kg) with TMZ (17 and 34 mg/kg) resulted in 100% complete regression of U251MG tumors by day 28 versus 60% complete regression caused by TMZ alone. CEP-6800 (30 mg/kg) in combination with irinotecan (10 mg/kg) resulted in a 60% inhibition of HT29 tumor growth versus irinotecan alone by day 33. The combination therapy of cisplatin (5 mg/kg) with CEP-6800 (30 mg/kg) caused a 35% reduction in Calu-6 tumor growth versus cisplatin alone by day 28. These data suggest that CEP-6800 could be used as a chemopotentiating agent with a variety of clinically effective chemotherapeutic agents.

The use of intravascular stents in the femoropopliteal artery (FPA) continues to be controversial due to the potential fractures in the dynamic environment. The purpose of this study was to (1) develop a representative in-vitro model that simulates physiological motion of the FPA during knee and hip flexion and (2) use the model to characterize the types and ranges of stent distortion produced by extremity movement. This model eliminates inconsistencies often observed in cadaveric models and clinical subjects due to individual anatomical differences, and allows testing with large sample sizes in a controlled environment for variable (tubing length, material, diameter, and thickness) modification. A comparative evaluation of axial mechanical property and elasticity was conducted between the tubing intended to simulate arteries and the ex-vivo porcine carotid arteries, favoring the selection of silicone tubing. The model was assessed for its unstented and stented arterial bending and axial compression under three physiological motions: straight leg, walking (knee/hip flexion 70°/20°), and sitting/stair climbing (knee/hip flexion 90°/90°). Self-expanding nitinol stents implanted in the simulated mid-superficial femoral artery and popliteal artery (PA) of the model exhibit axial compression of 4.5±0.3 % and 7±0.3 % (knee/hip flexion 70°/20°), and 8.4±0.7 % and 8±0.2 % (knee/hip flexion 90°/90°). Stents implanted in the simulated PA exhibit bending of 40° and 74° from knee/hip angle changes to 70°/20° and to 90°/90°, respectively. The model demonstrated stent bending and compression as previously observed in cadaver studies. Additional analysis of stent motion (torsion, localized bending, radial compression) may be evaluated with more advanced imaging techniques and additional model development. The data generated in these analyses could support appropriate modes and parameters for stent fatigue testing, and better understanding of vascular device performance in the dynamic FPA.