Matrix metalloproteinase inhibitor, MMI270 (CGS27023A) inhibited hematogenic metastasis of B16 melanoma cells in both experimental and spontaneous metastasis models.

Matrix metalloproteinases (MMP) have been implicated in several steps of tumor metastasis, such as invasion in the extracellular matrix, intravasation, extravasation, and growth in a distant organ site. Various synthetic MMP inhibitors have been reported to suppress tumor metastasis in animal models. However, there are few reports describing which steps in the metastasis process are most critical for inhibition by MMP inhibitors. In the experimental lung colonization model by i.v. injection of mouse B16-F10 melanoma cells, we found that the daily administration of MMI270 for 2 weeks significantly decreased the number of colonies in the lung compared with the control without affecting the size of colony. Micrometastasis was monitored day 7 post-inoculation by measuring the melanin content in the lung as well as by microscopic examination of the lung tissue sections. Even only twice administrations of MMI270 on the first day after tumor injection significantly inhibited micrometastasis in the lung. In the spontaneous metastasis model using B16-BL6 melanoma cells, lung metastasis was not affected by a continuous administration of MMI270 using a mini osmotic-pump. On the contrary, when mice were subjected to popliteal lymphadenectomy on day 7 after the cell inoculation in the footpad subdermis, the continuous administration of MMI270 significantly suppressed the lung metastasis. These results suggest that the tumor cell extravasation in the target organ is the most critical step where MMPs can play their significant role in the experimental metastasis, and that the lymphatic metastasis process is less susceptible to MMI270 than the hematogenic metastasis process in the spontaneous metastasis model.

Treatment of cold injury-induced brain edema with a nonspecific matrix metalloproteinase inhibitor MMI270 in rats.

Blood-brain barrier (BBB) disruption is a critical event leading to vasogenic brain edema and secondary brain damage after cold injury-induced brain trauma. Matrix metalloproteinases (MMPs), a family of proteolytic enzymes which degrade the extracellular matrix, are implicated in BBB disruption in this model. The purpose of this study was to examine the effects of MMI270 (N-hydroxy-2(R)-[(4-methoxysulfony) (3-picolyl)-amino]-3-metylbutaneamide hydrochloride monohydrate), a synthetic nonspecific MMP inhibitor, on cold injury-induced brain edema in rats. Cold injury was induced by applying a copper probe cooled with liquid nitrogen on the parietal skull for 30 sec in 38 rats. Treatment with MMI270, a bolus injection at a dose of 30 mg/kg, was started immediately after the induction of cold injury and was continued for 24 h at a dose of 40 mg/kg/day using an intraperitoneal osmotic minipump (n = 7). In the untreated control group (n = 7), rats were administered a vehicle and implanted with a vehicle-containing osmotic pump. Two percent Evans Blue (EB) in saline (1 mL/kg) was administrated intravenously immediately after the cold injury in another group of rats, six of which were untreated and six of which were treated with MMI270 at the above dose. At 24 h after the cold injury, the brain water content and the BBB permeability to EB were determined. To assess the protective effect of MMI270 on secondary brain lesion after the cold injury, the MMI270-treated rats received a bolus injection at a dose of 30 mg/kg, followed by a continuous administration of MMI270 for 7 days at a dose of 40 mg/kg/day using an osmotic minipump (n = 6). In the untreated control group (n = 6), the rats were administered the vehicle and implanted with a vehicle-containing osmotic pump. At 7 days after cold injury, the secondary brain lesion was assessed using hematoxylin and eosin (H-E) staining. Compared with the untreated control group, treatment with MMI270 significantly reduced the brain water content in the ipsilateral core and intermediate areas (p < 0.05 and p < 0.01) and protected the BBB integrity to EB in the ipsilateral core area (p < 0.05) at 24 h after the cold injury. The secondary lesion was significantly smaller in the MMI270-treated animals compared with the untreated animals (p < 0.05) a 7 days after the cold injury. O kur results indicate that treatment with MMI270 in rats exhibits protection in acute brain edema formation and secondary brain damage by attenuating the BBB permeability after cold injury.

Ratio of immature cornified envelopes does not correlate with parakeratosis in inflammatory skin disorders.

We have previously established a non-invasive method to evaluate the maturity of cornified envelopes (CEs), and have reported the appearance of immature CEs in the stratum corneum (SC) with poor barrier function, such as the SC of the face. The purpose of the present study was to evaluate CEs in inflammatory skin disorders, and to clarify the relationship between the appearance of the immature CEs and parakeratosis, which is often used as a marker for defective keratinization in inflammatory skin disorders. Cornified envelopes in the outermost SC of involved areas of psoriasis vulgaris (PV) and atopic dermatitis (AD) were strikingly heterogeneous, and consisted of immature CEs stained with anti-involucrin and mature CEs stained with Nile red, whereas CEs of the uninvolved areas were relatively homogeneous, exhibiting mature phenotype. The ratio of immature CEs was significantly higher in the involved areas of PV and AD than that in the corresponding uninvolved areas, suggesting that defective CE maturation may, at least in part, account for the inflammatory disorders. Simultaneous evaluation of CE maturity and parakeratosis was carried out by a combination of involucrin immunostaining and nuclear staining of detergent-dissociated corneocytes. In the involved area of PV, four types of corneocytes in regard to the combination of involucrin staining and nuclear remnant were observed, while both immature CEs and parakeratosis were more often detected in the involved areas of PV than in the uninvolved areas or the upper arm of healthy subjects as a normal control. Thus, corneocytes with involucrin-positive immature CEs were not always associated with parakeratosis at the cellular level. In the involved areas of PV, the ratio of immature CEs and that of parakeratosis were heterogeneous, depending on the cases, and no correlation between the ratios was observed. Inter-individual and intraindividual variations in CE maturity were also suggested by the heterogeneous localization of involucrin in the psoriatic epidermis as examined by immunohistochemistry. In addition, in the face of healthy subjects, four types of corneocytes were similarly detected, and the ratio of immature CEs was significantly higher than that of parakeratosis. These results obviously suggest that the maturation of CEs and disappearance of nuclei are differentially regulated in the epidermis.

Plasma extravasation induced by dietary supplemented histamine in histamine-free mice.

Histidine decarboxylase (HDC) synthesizes endogenous histamine from histidine in mammals. To evaluate the role of histamine in skin allergic reaction, we used HDC gene knockout mice lacking histamine. No plasma extravasation reaction was observed in HDC-/- mice after passive cutaneous anaphylaxis (PCA) test. Compound 48/80, a mast cell granule depletor, produced plasma extravasation inHDC+/+ mice but no extravasation in HDC-/- mice. Interestingly, orally administered histamine was distributed in the skin in HDC-/- mice and in these histamine-supplemented mice the plasma extravasation reaction was observed after the injection of compound 48/80 and the PCA test. Cultured bone marrow-derived mast cells of HDC-/- mice took up histamine from the histamine-supplemented medium into the secretory granules. The absorbed histamine was released in response to the same antigen and antibody combination used as in PCA test. In contrast to the immediate-type response, the delayed-type hypersensitive response, observed as a thickening of the ear skin after trinitrochlorobenzene challenge (following sensitization), showed no differences between HDC+/+ and HDC-/- mice. Therefore, among the allergic skin reactions, histamine is revealed to be an important mediator especially for the plasma extravasation in an immediate-type allergy model.

Cutaneous late phase reaction in adult atopic dermatitis patients with high serum IgE antibody to Dermatophagoides farinae: correlation with IL-5 production by allergen-stimulated peripheral blood mononuclear cells.

It is known that, in patients of allergic asthma and rhinitis, the late-phase reaction (LPR) occurs 6-12 h after allergen challenge, but there are few reports concerning cytokine production in the cutaneous LPR in atopic dermatitis (AD). We report here the results of our study on the relationship between the cutaneous LPR and the production of cytokines such as IL-4, IL-5, IL-2 and IFN-gamma by peripheral blood mononuclear cells (PBMC) of AD patients. We selected 29 pure AD patients with no history of atopic airway diseases who showed high serum IgE antibody against Dermatophagoides farinae and performed skin prick testing with three different antigens and observed the resultant cutaneous reactions in 23 of the AD patients. Furthermore, we measured the cytokine production by the cultured PBMC under the stimulation of the antigens and compared it with the results of the skin tests. 13 (57%) of these 23 AD patients demonstrated positive LPR in response to D. farinae, and the mean concentration of IL-5 produced by PBMC was higher in these LPR-positive AD patients compared to the LPR-negative ones. Additionally, we noticed that there was a positive correlation between the mean diameter of the erythema of LPR and the level of IL-5 production by PBMC in the LPR-positive patients. We suggest that there are at least two groups in AD patients, i.e. LPR-positive and LPR-negative ones. The observation of LPR can be an important and practical way to classify AD patients into subgroups, which may enable us to regard IL-5 or eosinophils as a target for treatment.