A novel model of HPV infection in meshed human foreskin grafts.

The present study describes a novel meshing procedure that provided successful low-risk papillomavirus propagation and reproducible wart induction in human foreskin xenografts. The initial HPV6 and/or 11 inocula were collected from clinically excised human wart tissues and confirmed to be free of HPV16, 18 and 31 by PCR analysis. Human foreskin grafts were collected from a circumcision clinic, and pre-inoculated with HPV virions by scarification. Meshing was carried out with a Zimmer Skin Grafter Mesher. Grafts were cut to appropriate size (1cm x 1cm or 5mm x 5mm) for cutaneous or subcutaneous grafting to NIH-nu-bg-xid mice under halothane anesthesia. Cutaneous xenografts were dressed with antibiotics and protective band-aids for 3 weeks. In the paralleled experiment using the same viral stock containing both HPV6 and 11, and matched grafts, no visible papillomas were observed in non-meshed cutaneous xenografts (n = 4 up to 6 months). In comparison, six of eight cutaneous xenografts treated with the meshing procedure formed visible papillomas within 4 months. This high frequency of distinct papilloma induction over the surface of meshed xenografts were reproduced in subsequent experiments with viral stocks containing both HPV11 and 6 (8 out of 10 grafts), or with a single-type HPV11 inoculum (80-100%). In contrast, an initial viral stock of single-type HPV6 provided lower frequency and more delayed papilloma induction. Serial passage of HPV6 in the meshed xenograft appeared to improve both the induction frequency and growth rate up to the 3rd generation. Histology, in situ hybridization, and immunohistochemical analysis revealed similarity of xenograft warts to those observed in the clinic. The highly reproducible papilloma induction rate and successful viral stock propagation associated with the meshing procedure provide a novel feature in the HPV xenograft model.

A novel oral vehicle for poorly soluble HSV-helicase inhibitors: PK/PD validations.

PURPOSE: The current study describes the design and validation of a novel oral vehicle for delivering poorly water-soluble herpes simplex virus (HSV)-helicase inhibitors in preclinical pharmacokinetic (PK) and pharmacodynamic (PD) evaluations. METHODS: Poorly water-soluble compounds were used in solubility and drinking compliance tests in mice. A preferred vehicle containing 0.1% bovine serum albumin (BSA), 3% dextrose, 5% polyethylene glycol (PEG) 400, and 2% peanut oil, pH 2.8 with HCL (BDPP) was selected. This vehicle was further validated with oral PK and in vivo antiviral PD studies using BILS 45 BS. RESULTS: Solubility screen and drinking compliance tests revealed that the BDPP vehicle could solubilize BILS compounds at 0.5-3 mg/ml concentration range and could be administered to mice without reducing water consumption. Comparative oral PK of BILS 45 BS in HCL or BDPP by gavage at 40 mg/kg showed overlapping PK profiles. In vivo antiviral efficacy and potency of BILS 45 BS in BDPP by oral gavages or in drinking water were confirmed to be comparable as that achieved by gavage in HCL solution. CONCLUSIONS: These results provide a protein-enriched novel oral vehicle for delivering poorly water-soluble antiviral compounds in a continuous administration mode. Similar approaches may be applicable to other poorly soluble compounds by gavage or in drinking solution.

Oral bioavailability and in vivo efficacy of the helicase-primase inhibitor BILS 45 BS against acyclovir-resistant herpes simplex virus type 1.

This study investigated the oral bioavailability and efficacy of BILS 45 BS, a selective herpes simplex virus (HSV) helicase-primase inhibitor, against acyclovir (ACV)-resistant (ACV(r)) infections mediated by the HSV type 1 (HSV-1) dlsptk and PAA(r)5 mutant strains. In vitro, the compound was more potent than ACV against wild-type clinical and laboratory HSV-1 strains and ACV(r) HSV isolates, as determined by a standard plaque reduction assay, with a mean 50% effective concentration of about 0.15 microM. The oral bioavailability of BILS 45 BS in hairless mice was 49%, with a peak concentration in plasma of 31.5 microM after administration of a single dose of 25 mg/kg. Following cutaneous infection of nude mice, both the HSV-1 dlsptk and PAA(r)5 mutant strains induced significant, reproducible, and persistent cutaneous lesions that lasted for more than 2 weeks. Oral treatment with ACV (100 or 125 mg/kg/day, three times a day by gavage) did not affect either mutant-induced infection. In contrast, BILS 45 BS at an oral dose of 100 mg/kg/day almost completely abolished cutaneous lesions mediated by both ACV(r) HSV-1 mutants. The 50% effective doses of BILS 45 BS were 56.7 and 61 mg/kg/day against dlsptk- and PAA(r)5-induced infections, respectively. Taken together, our results demonstrate very effective oral therapy of experimental ACV(r) HSV-1 infections in nude mice and support the potential use of HSV helicase-primase inhibitors for the treatment of nucleoside-resistant HSV disease in humans.