Masahiro Harada

Scratching behavior in spontaneous- or allergic contact-induced dermatitis in NC/Nga mice.

Abstract:  NC/Nga mice have pathological and behavioral features similar to those seen in human atopic dermatitis. There are two known dermatitis models in NC/Nga mice, one being spontaneous‐induced dermatitis under conventional conditions and the other 2,4,6‐trinitrochlorobenzene (TNCB)‐induced allergic contact dermatitis. However, there are significant differences in time course on development of dermatitis. We studied the role of scratching behavior (sign of itch) on the development of dermatitis on spontaneous‐ and TNCB‐induced dermatitis. We measured scratching counts, transepidermal water loss (TEWL), and skin inflammation score, under conventional conditions or by applying 5% TNCB once a week for 6 weeks in NC/Nga mice. In spontaneous‐induced dermatitis, scratching counts increased with the passage of time. The scratching counts were significantly increased only 1 week after housing the mice under conventional conditions, but no changes were observed in cases of TNCB‐induced dermatitis. In spontaneous‐induced dermatitis, TEWL and skin‐inflammation score were gradually increased, time‐dependently. On the other hand, in TNCB‐induced dermatitis, these dependent values rapidly increased and reached a maximum only after 24 h TNCB application. These data suggest that pathogenesis of spontaneous‐ and allergic contact‐induced dermatitis was clearly different. It will be of major interest to identify the pruritic mediators causing profound scratching behavior and scratching‐induced aggravation of inflammation in the spontaneous‐induced dermatitis, as opposed to the inflammatory mediators that cause contact allergic dermatitis without major scratching.

Preparation and evaluation of biodegradable microspheres containing a new potent osteogenic compound and new synthetic polymers for sustained release.

In order to achieve the sustained release of 3-ethyl-4-(4-methylisoxazol-5-yl)-5-(methylthio) thiophene-2-carboxamide (BFB0261), a new potent osteogenic compound for the treatment of bone disorders, we prepared microspheres containing BFB0261 and newly synthesized three poly (D, L-lactic acid) (PLA), four poly (D, L-lactic acid-co-glycolic acid) (PLGA), and eight poly (D, L-lactic acid)-block-poly(ethylene glycol) (PLA-PEG) biodegradable polymers or copolymers, and evaluated the release pattern of BFB0261 from the microspheres in vitro and in vivo. The mean particle size of the microspheres, except for the microspheres constructed from PLA-PEG with a greater than 20% PEG component, was in the range of approximately 10-50 microm, and the preparations showed a spherical shape with a smooth surface. In an in vitro release study, the release of BFB0261 from PLA-1 (Mw: 36 kDa), PLAPEG9604H (PLA/PEG ratio: 96:4, Mw: 181 kDa), or PLAPEG8317 (PLA/PEG ratio: 83:17, Mw: 106 kDa) microspheres occurred in a zero-order manner with a slow release, and more than 50% of BFB0261 remained in each type of microsphere at 12 weeks after incubation. When the BFB0261 microspheres constructed from various polymers were intramuscularly administered to the rat femur, the microspheres constructed from PLA-1 or PLAPEG9604H were able to achieve a sustained release of BFB0261 at the injection site for 6 weeks. The present information indicates that microspheres constructed from PLA-1 or PLAPEG9604H may be feasible for bone engineering.

Effects of combined treatment with eldecalcitol and alendronate on bone mass, mechanical properties, and bone histomorphometry in ovariectomized rats: A comparison with alfacalcidol and alendronate

Eldecalcitol (ELD), a 2β-hydroxypropyloxy derivative of 1α,25 (OH) 2D3, inhibits bone resorption more potently than alfacalcidol (ALF) while maintaining osteoblastic function in an ovariectomized (OVX) osteoporosis rat model. Alendronate (ALN), which is the most common bisphosphonate used for the treatment of osteoporosis, increases the bone mineral density (BMD) by suppressing bone resorption. In this study, we investigated the effects of combination treatments with ELD and ALN or with ALF and ALN on bone mass and strength in OVX rats. Seventy female rats, 32 weeks old, were assigned to seven groups: (1) a sham-operated control group; (2) an OVX-control group; (3) an ELD group; (4) an ALF group; (5) an ALN group; (6) an ELD+ALN group; and (7) an ALF+ALN group. OVX rats were orally treated with ELD (0.015 μg/kg), ALF (0.0375 μg/kg), or ALN (0.2mg/kg) daily for 12 weeks. In both the lumbar spine and the femur, ELD and ALF monotherapy significantly increased the BMD, and ELD+ALN and ALF+ALN significantly increased the BMD, compared with ALN monotherapy, as an additive effect. In particular, ELD+ALN resulted in a significantly higher BMD than ALF+ALN in the femur. On mechanical testing of the lumbar spine, ELD and ALF monotherapy significantly increased the ultimate load, and ELD+ALN and ALF+ALN significantly increased the ultimate load compared with ALN monotherapy. In the femur, ELD, ELD+ALN, and ALF+ALN treatment significantly increased the ultimate load, compared with the OVX-control group, and ELD+ALN resulted in a significantly higher ultimate load than ALN monotherapy. A histomorphometric analysis showed that ELD monotherapy and ELD+ALN combination therapy had a potent inhibitory effect on bone resorption parameters (osteoclast surface and eroded surface), while maintaining bone formation parameters (osteoblast surface and osteoid surface). By contrast, ALF and ALF+ALN significantly lowered the histological parameters of both bone resorption and formation. These results suggested that ELD or ALF used in combination with ALN has therapeutic advantages over ALN monotherapy, with ELD+ALN combination treatment producing an especially beneficial anti-osteoporotic effect by inhibiting osteoclastic bone resorption and maintaining osteoblastic function, compared with ALF+ALN combination treatment.

26,27-Hexafluoro-1,25-dihydroxyvitamin D3 (F6-1,25(OH)2D3) prevents osteoporosis induced by immobilization combined with ovariectomy in the rat

The effect of 26,27-hexafluoro-1,25-dihydroxyvitamin D3 (F6-1,25(OH)2D3) on experimental osteoporosis in the rat induced by a combination of immobilization and ovariectomy was evaluated. F6-1,25(OH)2D3 increased the femur score and the photo-density. The administration of F6-1,25(OH)2D3 also significantly increased the dry weight, the ash weight and the ash content of the bone. Both F6-1,25(OH)2D3 and 1 alpha(OH)D3 showed a nearly dose-dependent effect and significant inhibition of the decrease of bone mass. Histomorphometry revealed a significant decrease of resorption by the administration of F6-1,25(OH)2D3. Bone formation rate in the F6-1,25(OH)2D3 treated group significantly decreased compared with the vehicle group. In conclusion, the pharmacological effective dose of F6-1,25(OH)2D3 was considered to prevent the osteoporotic decrease of bone mass by suppressing the elevated bone turnover.

The importance of brain PGE2 inhibition versus paw PGE2 inhibition as a mechanism for the separation of analgesic and antipyretic effects of lornoxicam in rats with paw inflammation.

Objectives Lornoxicam is a non‐selective cyclooxygenase inhibitor that exhibits strong analgesic and anti‐inflammatory effects but a weak antipyretic effect in rat models. Our aim was to investigate the mechanism of separation of potencies or analgesic and antipyretic effecls of lornoxicam in relatioin to its effect on prostaglandin E2 (PGE2) production in the inflammatory paw and the brain.

Effects on cultured neonatal mouse calvaria of 1α,25-dihydroxyvitamin D3,26,26,26,27,27,27-hexafluoro-1α,25-dihydroxyvitamin D3 and 26,26,26,27,27,27-hexafluoro-1α,23S,25-trihydroxyvitamin D3

Summary The potency of 26,26,26,27,27,27-hexafluoro-1α,25-dihydroxyvitamin D 3 (26,27-F 6 -1,25(OH) 2 D 3 ) to enhance bone calcium (Ca) mobilization in vitro was higher than that of 1α,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ). In a 48-h organ culture system using fetal rat limb bones, effects of 26,27-F 6 -1,25(OH) 2 D 3 on bone resorption were similar to those of 1,25(OH) 2 D 3 . Thus, we attempted to clarify whether or not the potency of 26,27-F 6 -1,25(OH) 2 D 3 in bone resorption in vitro would be higher than that of 1,25(OH) 2 D 3 . Calvarial bones from neonatal mice were used as explants and the culture period was extended to 144 from 48 h. In cultures of 0 to 48 h, both drugs increased the release of prelabeled 45 Ca from cultured calvariae, in a dose-dependent manner. In cultures of 48 to 144 h, 26,27-F 6 -1,25(OH) 2 D 3 was much more effective than 1,25(OH) 2 D 3 regarding indices of bone resorption. 26,26,26,27,27,27-F 6 -1α,23S,25-trihydroxyvitamin D 3 (26,27-F 6 -1,23,25(OH) 3 D 3 ), a main metabolite of 26,27-F 6 -1,25(OH) 2 D 3 in rats, stimulated 45 Ca release equipotently to 1,25(OH) 2 D 3 . In mouse bone marrow cells cultured for 7 days, the potency of 26,27-F 6 -1,25(OH) 2 D 3 on osteoclast formation was much higher than 1,25(OH) 2 D 3 . These results suggest that the higher potency of 26,27-F 6 -1,25(OH) 2 D 3 in bone resorption may be due at least in part to both the higher potency of 26,27-F 6 -1,25(OH) 2 D 3 in osteoclast formation and the larger retention of 26,27-F 6 -1,23,25(OH) 3 D 3 in calvariae.

Calcium regulating activity of 26,27-dimethyl analog of 24R,25-dihydroxyvitamin D3.

To determine the possibility that methyl substitution in 26- and 27-positions of 24R,25-dihydroxyvitamin D3 [24,25(OH)2D3] alters activities of the original compound, the effects of 24,25(OH)2D3 on calcium (Ca) regulating activity were compared with those of its methyl analog [24,25(OH)2(CH3)2D3] in addition to 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3]. 24,25(OH)2D3 at 10-6 M and 24,25(OH)2(CH3)2D3 at 10-7 M and above significantly stimulated both bone resorption in neonatal mouse calvaria cultures and formation of osteoclast-like multinucleated cells (MNC) in mouse bone marrow cultures. A stimulative effect of 1,25(OH)2D3 on bone resorption and MNC formation was recognized in very low concentrations (10-11 M and above). Although a potency of 24,25(OH)2(CH3)2D3 in stimulating bone calcium (Ca) mobilization and intestinal Ca transport was higher than that of 24,25(OH)2D3, the potencies of both compounds were similar to that of 1,25(OH)2D3 unlike in vitro experiments. As 1,24R,25-trihydroxy-26,27-dimethylvitamin D3 showed almost the same effect as 24,25(OH)2(CH3)2D3, the dihydroxy form is suggested to be hydroxylated at 1α position and converted to trihydroxy form in vitamin D-deficient rats. From these results, methyl substitution in 26- and 27-position of 24,25(OH)2D3 was found to elevate Ca regulating activity of the original compound. In addition, it is suggested that the basis for a similarity in potency between 1,25(OH)2D3 and 24,25(OH)2D3 or its dimethyl analog in vitamin D-deficient rats is likely the result of 1 α-hydroxylation.

Calcium regulating activity of 24a-homo-24,24-difluoro-1α,25-dihydroxyvitamin D3 and 26,27-dimethyl-24,24-difluoro-1α,25-dihydroxyvitamin D3

SummaryTwo fluoro analogs of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3], 24a-homo-24,24-difluoro-1α,25-dihydroxyvitamin D3 [24aF2-homo-1,25(OH)2D3], and 26,27-dimethyl-24,24-difluoro-1α,25-dihydroxyvitamin D3 [24F2-1,25(OH)2(Me)2D3] were examined for calcium (Ca)-regulating activity. The objective of the present study was to determine whether or not fluoro substitution at 24-position would alter activities of the original compounds, that is, 26,27-dimethyl 1α, 25-dihydroxyvitamin. D3[1,25(OH)2 (Me)2D3] and 24-homo-1α,25-dihydroxyvitaminD3[24homo-1,25(OH)2D3], respectively. The relative activities of 24aF2-homo-1,25(OH)2D3, 24F2-1,25(OH)2(Me)2D3, and 1,25(OH)2D3 in competing with 1,25(OH)2D3 for binding to chick intestinal cytosol receptor were 0.28:0.5:1.0. The relative potencies of the same series of compounds in competition for the vitamin D-deficient rat serum binding sites were 0.04:0.15:1. Bone-resorbing activities of two fluoro analogs in cultures of neonatal mouse parietal bones were more potent than that of 1,25(OH)2D3. Similar results were recognized in stimulating activities of osteoclast-like cell formation. Responses of two fluoro analogs to intestinal Ca absorption were similar to that of 1,25(OH)2D3. The potencies of 1,25(OH)2D3. and its fluoro analogs in bone Ca mobilization were the highest with 1,25(OH)2D3. followed by 24F2 1,25(OH)2(Me)2D3 and 24aF2-homo-1,25(OH)2D3, in that order. From these results and the data of Paulson et al. [24], fluoro substitution in 24-position of 1,25(OH)2D3. apparently does not alter their activities, hence, the fluoro substitution at 24-position of 1,25(OH)2D3. and the elongation of side chain of 1,25(OH)2D3. may not intensify Ca-regulating activity.

Preparation and evaluation of biodegradable films containing the potent osteogenic compound BFB0261 for localized delivery

To achieve sustained release of 3-ethyl-4-(4-methylisoxazol-5-yl)-5-(methylthio) thiophene-2-carboxamide (BFB0261), a new potent osteogenic compound for treating bone disorders, we prepared film formulations containing BFB0261 and the following newly synthesized biodegradable polymers by a solvent casting technique: poly(D,L-lactic acid) (PLA), poly(D,L-lactic acid-co-glycolic acid) (PLGA), poly(D,L-lactic acid)-block-poly(ethylene glycol) (PLA-PEG), and poly(D,L-lactic acid-co-trimethylene carbonate) (PLA-TMC) polymers or copolymers. Powder X-ray diffractometry (PXRD), differential thermal analysis (DTA), scanning electron microscopy (SEM), and tensile testing were performed to examine the physicochemical properties of these films. Almost all the films exhibited a smooth and homogeneous surface, as observed by SEM. In addition, PXRD and DTA revealed that BFB0261 existed in an amorphous state in the films. The in vitro release of BFB0261 from PLA100 (M(w): 251 kDa), PLAPEG9604H (PLA/PEG ratio: 96:4; M(w): 181 kDa), PLAPEG8515H (PLA/PEG ratio: 85:15; M(w): 51.5 kDa), or PLAPEG8020 (PLA/PEG ratio: 80:20; M(w): 33.7 kDa) films followed zero-order kinetics with slow release up to 12 weeks following incubation. Although release of BFB0261 from PLA-TMC films followed first-order kinetics, sustained release of BFB0261 for 12 weeks was still observed for PLATMC8416 (PLA/TMC ratio: 84:16; M(w): 170 kDa) films. Furthermore, when the BFB0261-loaded films constructed from various polymers were implanted subcutaneously on rat backs, the PLAPEG8515H and PLATMC8416 films were capable of achieving sustained release of BFB0261 at the administrated site for 12 weeks. Therefore, the present data indicate that films constructed from PLAPEG8515H or PLATMC8416 may be applicable to bone or tissue engineering.

Elongation of the side chain of analogs of 1α,25-dihydroxyvitamin D3 prevents osteopenia in a rat model

Five analogs of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] [1], 26,27-dimethyl-1α,25-dihydroxyvitamin D3 [1,25(OH)2(Me)2D3] [2], 26,27-dimethyl-1α,25-dihydroxyvitamin D3 [1,25(OH)2(Et)2D3] [3], 26,27-dipropyl-1α, 25-dihydroxyvitamin D3 [1,25(OH)2(Pr)2D3] [4], 26,27-dimethyl-24, 24-difluoro-1α,25-dihydroxyvitamin D3 [24F2-1,25(OH)2(Me)2D3, and [5] 24a-homo-24,24-difluoro-1α,25-dihydroxyvitamin D3 [24aF2-homo-1,25(OH)2D3] were investigated to clarify the possibility that prevents osteopenia induced in rats by ovariectomy and sciatic neurotomy. The objective of our studies was to determine whether these analogs may be effective for treatment of subjects with osteoporosis. 1,25(OH)2(Me)2D3, 24F2-1,25(OH)2(Me)2D3, and 24aF2-homo-1,25(OH)2D3 prevented decreases in bone mineral density (BMD) of the femur, as measured by dual energy X-ray absorptiometry (DXA). The potency of 1,25(OH)2(Me)2D3 in this test was higher than that of 1,25(OH)2D3. The potencies of 24F2-1,25(OH)2(Me)2D3 and 24aF2-homo-1,25(OH)2D3 were similar to that of 1,25(OH)2D3. On the other hand, though 1,25(OH)2(Et)2D3 and 1,25(OH)2(Pr)2D3 had a preventive effect on the decease in BMD, the potency of two analogs was lower than that of 1,25(OH)2D3. Decreases in cortical and trabecular bone areas of the femur were prevented by three analogs of 1,25(OH)2D3, 1,25(OH)2(Me)2D3, 24F2-1,25(OH)2(Me)2D3, and 24aF2-homo-1,25(OH)2D3. Serum calcium (Ca) concentration was elevated at the last administration of three analogs of 1,25(OH)2D3, 1,25(OH)2(Me)2D3, 24F2-1,25(OH)2(Me)2D3 and 24aF2-homo-1,25(OH)2D3. Decreases in the Ca concentration in untreated rats were noted a few days after the last administration. In light of these positive effects, we are continuing research on 1,25(OH)2(Me)2D3, 24F2-1,25(OH)2(Me)2D3, and 24aF2-homo-1,25(OH)2D3 as putative treatment for osteoporosis.