Accumulation of ACE inhibitory tripeptides, Val-Pro-Pro and Ile-Pro-Pro, in vascular endothelial cells.

The antihypertensive peptides, Val-Pro-Pro and Ile-Pro-Pro, were successfully detected in the aorta of spontaneously hypertensive rats after orally administering these peptides by a guanidine-thiocyanate treatment to prevent proteolysis. Cy3-labeled versions of both peptides were localized in the endothelial cells of arterial vessels in the rats. The accumulation of both peptides in the endothelial cells suggested in vivo inhibitory activity of the angiotensin I-converting enzyme.

Molecular characterization of chicken prion proteins by C-terminal-specific monoclonal antibodies.

We obtained seven monoclonal antibodies (mAbs) against chicken cellular prion protein (ChPrP(C)) by immunizing BALB/c mice with recombinant prion protein (rChPrP). Of the seven mAbs, two mAbs (6 and 26) could recognize rChPrP, but not ChPrP(C), in chicken brain lysate via Western blot (WB) analysis. Three C-terminal linear epitopes (AAANQTEVEM, RWWS and SPVPQD) were identified in ChPrP amino acids by pepspot analysis with five mAbs. The mAbs recognizing the C-terminal epitopes in ChPrP(C) predominantly reacted with the N-terminal truncated ChPrP(C) in WB analysis, which differed from the reaction with N-terminal proline/glycine-rich repeats recognizing rabbit polyclonal antibody. These mAbs will soon be available as a useful tool to characterize the biology of ChPrP(C) in birds.

[Treatment of lumbar intervertebral disc displacement with chondroitinase ABC--experimental basis for clinical application].

After single intradiscal injection of C-ABC in rabbit inter-vertebral discs, water content in the matrix of nucleus pulposus diminished clearly. After similar injection of C-ABC in sheep discs, disc inner pressure was diminished. After single intradiscal injection of C-ABC in dog inter-vertebral discs suffering disc herniation, the syndromes coming from the herniation diminished or disappeared. Based on these observations C-ABC is expected to be a chemonucleolytic agent and a human clinical trial is now in progress.

Chondroitinase ABC combined with neural stem/progenitor cell transplantation enhances graft cell migration and outgrowth of growth-associated protein-43-positive fibers after rat spinal cord injury.

We previously reported that the transplantation of neural stem/progenitor cells (NSPCs) can contribute to the repair of injured spinal cord in adult rats and monkeys. In some cases, however, most of the transplanted cells adhered to the cavity wall and failed to migrate and integrate into the host spinal cord. In this study we focused on chondroitin sulfate proteoglycan (CSPG), a known constituent of glial scars that is strongly expressed after spinal cord injury (SCI), as a putative inhibitor of NSPC migration in vivo. We hypothesized that the digestion of CSPG by chondroitinase ABC (C-ABC) might promote the migration of transplanted cells and neurite outgrowth after SCI. An in vitro study revealed that the migration of NSPC-derived cells was inhibited by CSPG and that this inhibitory effect was attenuated by C-ABC pre-treatment. Consistently, an in vivo study of C-ABC treatment combined with NSPC transplantation into injured spinal cord revealed that C-ABC pre-treatment promoted the migration of the transplanted cells, whereas CSPG-immunopositive scar tissue around the lesion cavity prevented their migration into the host spinal cord in the absence of C-ABC pre-treatment. Furthermore, this combined treatment significantly induced the outgrowth of a greater number of growth-associated protein-43-positive fibers at the lesion epicentre, compared with NSPC transplantation alone. These findings suggested that the application of C-ABC enhanced the benefits of NSPC transplantation for SCI by reducing the inhibitory effects of the glial scar, indicating that this combined treatment may be a promising strategy for the regeneration of injured spinal cord.

Hylan G-F 20 induces delayed foreign body inflammation in Guinea pigs and rabbits.

Recent clinical evidence suggests that hylan, a modified hyaluronan, and related products potentially elicit foreign body granulomatous inflammation in human soft tissue. We investigated the biocompatibility of hylan G-F 20 (Synvisc) for up to 28 days after intradermal injection in guinea pigs and intramuscular injection in rabbits. Compared to saline and unmodified hyaluronan, hylan induced definitive macroscopic changes in guinea pigs by day 14 or later and in rabbits by 28 days after injection. Histologically, at the injection sites, there was severe granulomatous inflammation in guinea pigs and acute inflammation with minimal infiltration of macrophages and foreign body giant cells in rabbits. Furthermore, specific antibodies against hylan were demonstrated in guinea pigs by passive cutaneous anaphylaxis, and substantial deposits of IgG on hylan were evident by immunohistochemistry. The present results contradict previous reports on biocompatibility of hylan and suggest that hylan may potentially induce similar unfavorable reactions in humans.

Effect of chondroitinase ABC on matrix metalloproteinases and inflammatory mediators produced by intervertebral disc of rabbit in vitro.

STUDY DESIGN: Lumbar intervertebral discs in rabbit were cultured in the presence of chondroitinase ABC. The matrix metalloproteinases (MMPs) and inflammatory mediators produced in culture media were then analyzed. OBJECTIVES: To investigate the effect of chondroitinase ABC on MMPs and inflammatory mediators produced by intervertebral disc of rabbit in vitro. SUMMARY OF BACKGROUND DATA: The chemonucleolytic effect of chondroitinase ABC is caused by the decrease in the chondroitin sulfate, hyaluronan, and protein content of the nucleus pulposus in rabbit. The reason for the decreases in protein content remains unclear. METHODS: Anulus fibrosus and nucleus pulposus were cultured for 72 hours with or without chondroitinase ABC stimulated or not stimulated by interleukin-1 after preculture for 4 days. Subsequently, the MMPs (gelatinases MMP-2, MMP-9, and collagenase) and inflammatory mediators (prostaglandin E2 and nitric oxide) produced in the culture media were analyzed. RESULTS: In the anulus fibrosus chondroitinase ABC and interleukin-1 synergistically increased the collagenase activity, which was at a significantly higher level than the increment solely due to interleukin-1. In contrast, chondroitinase ABC counteracted the increase in nitric oxide production by interleukin-1. In the nucleus pulposus the collagenase and nitric oxide productions were not particularly affected by chondroitinase ABC and/or interleukin-1. In zymographic analysis MMP-2 was detected, but MMP-9 was only slightly detected in both tissues. There were no significant differences in both tissues for MMP-2 and prostaglandin E2 following incubation with or without chondroitinase ABC, whether stimulated by interleukin-1 or not. CONCLUSIONS: The collagenase activity in the anulus fibrosus was increased by chondroitinase ABC with interleukin-1. This finding may support the hypothesis that some proteolytic activities are involved in the chemonucleolytic process by chondroitinase ABC treatment.

Immunogenicity of hylan g-f 20 in Guinea pigs and mice.

OBJECTIVE: To determine the product-specific immunogenicity of a chemically-modified sodium hyaluronate derivative, hylan G-F 20, that is used in the treatment of osteoarthritis of the knee. METHODS: Guinea pigs were subcutaneously immunized with hylan G-F 20 (Synvisc) once a week for 3 weeks. After resting, these animals received an intradermal challenge with hylan to elicit allergic skin reactions. Animal sera were tested for the presence of hylan-specific antibodies by homologous passive cutaneous anaphylaxis (PCA) assay and of anti-hylan IgG by ELISA. Further, mice were similarly immunized with hylan, and their sera were analyzed by heterologous PCA assay in rats and by ELISA for anti-hylan Ig(G+M) and anti-hylan IgE. RESULTS: In the guinea pig studies, acute and delayed erythematous skin reactions were elicited in immunized animals after the intradermal challenge with hylan. The sera of hylan-immunized guinea pigs showed positive reaction in the homologous PCA assay and significantly high amount of anti-hylan IgG, whereas the sera did not show any cross-reactivity against sodium hyaluronate. Hylan also exhibited immunogenicity in mice of 3 inbred strains, and C3H/HeN mice showed higher production of anti-hylan antibodies than Balb/c and C57BL/6 mice. CONCLUSION: Hylan G-F 20 exhibited immunogenicity in guinea pigs and mice. Recent reported severe acute inflammatory reactions in human patients after repeated intraarticular injections of hylan G-F 20 might involve product-specific, immune-mediated mechanisms.