the description in this application is in particular directed to phenylbutyrate and trichostatin a in adjuvant arthritis , a model of connective tissue disease , as non - limiting examples and is not intended to limit the scope of the invention . phenylbutyrate and trichostatin a or derivatives thereof are disclosed to be useful as agents for the treatment in connective tissue disease . pharmaceutical formulations and the use of compounds of phenylbutyrate and trichostatin a are also disclosed . phenylbutyrate ( mw 164 . 21 ), a natural nontoxic colorless tasteless aromatic fatty acid purified from mammalian urine and plasma , is food and drug administration approved for children with hyperammonemia associated with inborn errors of urea synthesis and has been used for adult patients with hyperammonemia secondary to high - dose chemotherapy . it is metabolized in the liver and kidney to phenylacetate that is subsequently conjugated with glutamine to form phenylacetylglutamine ; the latter serves as vehicle for waste nitrogen excretion in the urine . phenylbutyrate has also been evaluated in the clinical trials for sickle cell anemia , beta - thalassaemia , cystic fibrosis , adrenal leukodystrophy , and both hematological and nonhematological malignancies . trichostatin a ( mw 164 . 21 ), a hydroxamic acid , is originally isolated from streptomyces hygroscopicus . trichostatin a is useful as an antifungal , anticancer , and antiprotozoal agent . in the course of experiments phenylbutyrate and trichostatin a were discovered that they as histone deacetylase inhibitors have strongly inhibitory effects on synovial hyperplasia , pannus formation , bone and cartilage destruction , skin inflammation or ulcer or fibrosis , lymphocyte infiltration , and proinflammatory mediator production in connective tissues of connective tissue disease resulting from altered patterns of immunoregulation as an autoimmune disorder . the histone deacetylase inhibitor agents can be brought in the form of pharmaceutically acceptable salts . as such pharmaceutically acceptable salts may be used so long as they do not adversely affect the desired pharmacological effects of the compounds . the selection and production can be performed by those skilled in the art . examples of pharmaceutically acceptable salts include alkali metal salts such as sodium salt or a potassium salt , alkaline earth metal salts such as calcium salt or a magnesium salt , salts with an organic base such as an ammonium salt , or a salt with an organic base such as a triethylamine salt or an ethanolamine salt . the histone deacetylase inhibitor agents of the present invention may be administered orally or non - orally . in the case of oral administration , they may be administered in the form of soft and hard capsules , tablets , granules , powders , solutions , suspensions or the like . in the case of non - oral administration , they may be administered in the form of creams , ointments , gels , lotions , patches , suppositories , liposome formations , injection solution , drip infusion formulations or the like whereby continued membrane absorption can be maintained in the form of solid , viscous liquid , or suspension . the selection of the method for the preparation of these formulations and the vehicles , disintegrators or suspending agents , can be readily made by those skilled in the art . the histone deacetylase inhibitor agents of the present invention may contain a further substance having anti - inflammatory activities , in addition to trichostatin a , or phenylbutyrate , and a pharmaceutically acceptable carrier or a pharmaceutically acceptable salt thereof . as recognized by those skilled in the art , the effective doses vary depending on route of administration , excipient usage , and the possibility of co - use with other therapeutic treatments such as the use of other anti - inflammatory agents . effective amounts and treatment regimens for any particular subject ( e . g ., human , dog , or cat ) will also depend upon a variety of other factors , including the activity of the specific compound employed , age , body weight , general health status , sex , diet , time of administration , rate of excretion , severity and course of the disease , and the patient &# 39 ; s disposition to the disease , but are usually from 0 . 1 to 50 % by weight irrespective of the manner of administration . in order that the invention described herein may be more readily understood , the following examples are set forth . it should be understood that these examples are for illustrative purposes only and are not to be construed as limiting this invention in any manner . all references cited herein are expressly incorporated by reference in their entirety . histone deacetylase inhibitors induce a dose - and time - dependent growth arrest in synovial fibroblasts of adjuvant arthritis of connective tissue disease the animal model for adjuvant arthritis , a model of connective tissue disease , has been established and characterized well ( winter ca , et al ., arthritis rheum . 1966 , 9 : 394 - 404 ). long evans rats weighing 150 ± 20 g and icr derived male mice weighing 22 ± 2 g provided by animal breeding center of mds pharma service - taiwan , ltd ., were used . space allocation for 5 mice was 45 × 23 × 15 cm . the animals were housed in apec ® ( allentown gaging , allentown , n . j ., usa ) cages and maintained in a hygienic environment under controlled temperature ( 22 - 24 ° c .) and humidity ( 60 - 80 %) with 12 - hours light / dark cycles for at least one week in mds pharma service - taiwan laboratory prior to being used . free access to standard lab chew for mice ( labdiet ® 5001 , usa ) and tap water was granted . all aspects of this work including housing , experimentation , and disposal of animals were performed in general according to the international guiding principles for biomedical research involving animals ( cioms publication no . isbn 9290360194 , 1985 ). a well - ground suspension of killed mycobacterium tuberculosis ( difco , usa ; 0 . 3 mg in 0 . 1 ml of light mineral oil ; complete freund &# 39 ; s adjuvant , cfa ) was administered into the subplantar region of the right hind paw immediately after first dosing on first day ( denoted day 1 ). hind paw volume was measured by plethsmometer ( cat . no . 7150 , ugo basile , italy ) and water cell ( 25 mm diameter , cat . no . 7157 , ugo basile , italy ) on day 0 ( before cfa treated ), 1 , 5 , 10 , and 15 after cfa of right paw ( with cfa ), and day 0 , 14 , and 18 of left paw ( without cfa ); rats were weighed just before first dose and 1 hour after final dose . right hind paw volume ( acute phase ) was measured 4 hours after cfa treated ( denoted as day 1 ) and day 5 , day 10 and day 15 after cfa . the contralateral left hind paw volume ( delayed phase ) was measured at day 14 and day 18 . the inflammatory activity in this model was denoted by values calculated during the acute phase as well as the delayed phase . at day 10 , synovial samples were obtained from the established adjuvant arthritis rats . the collected synovial tissues were digested with 5 mg / ml collagenase ( sigma ) and 1 . 5 mg / ml dnase ( sigma ), and were passed through a wire mesh to prepare isolated cells . cells ( 0 . 5 × 10 6 ) were placed in 10 - cm dishes with 10 ml rpmi 1640 medium ( gibco ) supplemented with 10 % fetal calf serum , 2 mm l - glutamine , 50 u / ml penicillin and 50 mg / ml streptomycin . cells were detached with trypsin - edta solution and passed for subculture when 90 % confluency was reached . the synovial cells used were of passage 5 . proliferating synovial fibroblasts from adjuvant arthritis were treated with phenylbutyrate or trichostatin a , and proliferation was determined by incorporation of 3 h - thymidine , which was present during last 24 hours of culture . 4 - phenylbutyrate ( merck ) dissolved in sterile water with naoh and adjusted to ph 7 . 2 , or sodium phenylbutyrate ( triple crown , u . s . a ) dissolved in sterile water or trichostatin a ( sigma ) dissolved in ethanol were used . nuclei from synovial fibroblasts were isolated by lysis of the cells in a buffer containing 10 mm tris - hcl ( ph 6 . 5 ), 50 mm sodium bisulfite , 1 % triton x - 100 , 10 mm mgcl 2 , and 8 . 6 % sucrose and use of a dounce homogenizer . histones were isolated by means of acid extraction . isolated histones ( 5 μg ) were then separated in 15 % polyacrylamide - 0 . 1 % sodium dodecyl sulfate minigels and transferred to nitrocellular filters . hyperacetylated histones were detected by use of the antibody that specifically recognizes the hyperacetylated form of histone h3 ( upstate biotechnology ). [ 0035 ] fig1 a and 1b are western blot result showing that phenylbutyrate and trichostatin a induce an accumulation of acetylated histones . fig2 a - 2 c are photographs of immunofluorescence with anti - acetylated h3 antibody ( upstate biotechnology ). the synovial fibroblasts were treated with or without phenylbutyrate ( 2 mm ) or trichostatin a ( 200 nm ) for 6 h , and then stained with fitc - conjungated anti - acetylated h3 antibody . phenylbutyrate and trichostatin a induce an accumulation of acetylated histones . fig3 a and 3b are diagrams showing that phenylbutyrate and trichostatin a exhibit a dose - and time - dependent growth inhibition in synovial fibroblasts from adjuvant arthritis . the results were expressed as percentage value relative to the control culture ( no drug addition ). data presented are the mean ± se of triplicate determinations from two experiments . fig4 a and 4b are western blot results showing that phenylbutyrate ( 2 mm ) and trichostatin a ( 200 nm ) treatment for 12 h induce upregulation of p16 and p21 , cell cycle inhibitors , in synovial fibroblasts from adjuvant arthritis . lane 1 : control ( no any treatment ); lane 2 : phenylbutyrate - treated ; lane 3 : trichostatin a - treated . 470 g of white petrolatum ( riedel - de haen ), 25 g of paraffin wax 50 / 52 ( local supplier ), and 5 g of 4 - phenylbutyrate ( merck ) were mixed in a beaker and heated at 70 ° c . to form a paste . the paste was stirred at 400 rpm for 1 hour , and then cooled at room temperature . 65 g of white petrolatum ( riedel - de haen ), 15 g of cetyl alcohol ( riedel - de haen ), 260 g of soft paraffin ( merck ), 155 g of liquid paraffin ( merck ), and 5 g of 4 - phenylbutyrate ( merck ) were mixed in a beaker and heated at 70 ° c . to form a paste . the paste was stirred at 400 rpm for 1 hour , and then cooled at room temperature . part i : 70 g of tefose 63 ®, 20 g of superpolystate ®, 10 g of coster 5000 ®, 15 g of myriyol 318 ®, 15 g of coster 5088 ®, and 15 g of gms se ® ( all commercially available from local supplier ) were mixed in a beaker and heated at 70 ° c . part ii : 5 . 739 g of sodium 4 - phenylbutyrate ( triple crown america , inc . ), 0 . 125 g of methylparaben ( merck ), 0 . 075 g of propylparaben ( merck ), and 149 . 061 g of deionized water were mixed in a beaker and heated at 70 ° c . the part ii was slowly added into the part i and continually stirred at 400 rpm for 5 minutes to form a mixture . 2 % stabileze qm ® ( prepared by dissolving 2 g of stabileze qm ® in 98 g of deionized water , heating and stirring at 70 ° c . to form a paste , and cooling at room temperature ) was added into the mixture and stirred for 5 minutes . the ph of the mixture was adjusted to 5 . 34 with 0 . 85 % phosphoric acid ( merck ), and stirred at 600 rpm for 20 minutes . the mixture was cooled at room temperature . part i : 10 g of stabileze qm ® and 232 . 035 g of deionized water were mixted in a beaker and heated at 70 ° c . part ii : 5 . 739 g of sodium 4 - phenylbutyrate ( triple crown america , inc . ), 0 . 125 g of methylparaben ( merck ), 0 . 075 g of propylparaben ( merck ), 232 . 035 g of deionized water , and 20 g of 10 % naoh were mixed in a beaker and heated at 70 ° c . the part ii was slowly added into the part i and continually stirred with 400 rpm for 20 minutes to form a mixture . the mixture was cooled at room temperature . part i : 10 g of stabileze qm ® and 380 . 561 g of deionized water were mixed in a beaker and heated at 70 ° c . part ii : 5 . 739 g of sodium 4 - phenylbutyrate ( triple crown america , inc . ), 0 . 125 g of methylparaben ( merck ), 0 . 075 g of propylparaben ( merck ), 83 . 5 g of 1 , 2 - propandiol , and 20 g of 10 % naoh were mixed in a beaker and heated at 70 ° c . the part ii was slowly added into the part i and continually stirred at 400 rpm for 20 minutes to form a mixture . the mixture was cooled at room temperature . two formulations were prepared according to the compositions listed in the table 1 . in this liposomal formulation , egg phosphatidylcholine ( epc ) and cholesterol were used in equi - or different - molar concentrations as primary lipid components . various liposomes located with 4 - phenylbutyrate were obtained by varying the lipid : phenylbutyrate ratio . liposomes were prepared by thin film hydration , sized by membrane extrusion , and physically evaluated . 472 . 5 g of white petrolatum ( riedel - de haen ), 27 g of paraffin wax 50 / 52 ( local supplier ), and 0 . 5 g of trichostatin a ( sigma ) were mixed in a beaker and heated at 70 ° c . to form a paste . the paste was stirred at 400 rpm for 1 hour , and then cooled at room temperature . 67 . 5 g of white petrolatum ( riedel - de haen ), 16 g of cetyl alcohol ( riedel - de haen ), 260 . 5 g of soft paraffin ( merck ), 155 . 5 g of liquid paraffin ( merck ), and 0 . 5 g of trichostatin a ( sigma ) were mixed in a beaker and heated at 70 ° c . to form a paste . the paste was stirred at 400 rpm for 1 hour , and then cooled at room temperature . effects of phenylbutyrate and trichostatin a on suppression of inflammation of skin , joints and soft tissues in connective tissue disease by topical administration . the animal model for connective tissue disease was established according to the report by winter c a , et al ., arthritis rheum . 1966 , 9 : 394 - 404 . groups of 5 long evans rats weighing 150 ± 20 g were used . the 10 % of phenylbutyrate cream and 1 % of trichostatin a ointment at a dose of 200 mg / paw and 10 mg / paw , respectively , were applied topically twice daily for 18 consecutive days . a well - ground suspension of killed mycobacterium tuberculosis ( difco , usa ; 0 . 3 mg in 0 . 1 ml of light mineral oil ; complete freund &# 39 ; s adjuvant , cfa ) was administered into the subplantar region of the right hind paw immediately after first dosing on first day ( denoted day 1 ). hind paw volume was measured by plethsmometer ( cat . no . 7150 , ugo basile , italy ) and water cell ( 25 mm diameter , cat . no . 7157 , ugo basile , italy ) on day 0 ( before cfa treated ), 1 , 5 , 10 , and 15 after cfa of right paw ( with cfa ), and day 0 , 14 , and 18 of left paw ( without cfa ); rats were weighed just before first dose and 1 hour after final dose . anti - inflammatory activity in this model was denoted by values calculated during the acute phase ( the right hind paw volume ) as well as the delayed phase ( the contralateral left hind paw volume ). for cfa - injected vehicle control rats , animals were also weighed on day 0 and day 18 ; cfa - injected vehicle control animals generally gain between 20 to 40 g body weight over this time period . a 30 % or more reduction in paw volume relative to vehicle treated controls was considered significant . table 2 shows the results which indicate that the 10 % of phenylbutyrate cream and the 1 % of trichostatin a ointment both have local anti - inflammatory effects on skin , joints , and soft tissues in connective tissue disease with prevention or amelioration of joint destruction , skin ulcer , soft tissue swelling , fibrosis and necrosis , and preservation of limb function . [ 0062 ] ( b ). in delayed phase ( contralateral ankle joint ) % inhibition relative to vehicle treated compound route dose day ( 14 - 0 ) day ( 18 - 0 ) day ( 18 - 14 ) 10 % of topical 200 mg / paw × 6 4 0 phenylbuty 2 × 18 rate cream 1 % of topical 200 mg / paw × 6 4 0 phenylbuty 2 × 18 rate cream cream vehicle topical 200 mg / paw × — — — 2 × 18 1 % of topical 10 mg / paw × 7 6 0 trichostatin 2 × 18 a ointment ointment vehicle topical 10 mg / paw × — — — 2 × 18 0 . 5 % cmc * po 10 mg / kg × 5 — — — hydrocortisone po 30 mg / kg × 5 ( 30 ) 27 20 referring to table 2 , systemic , orally administered hydrocortisone is used for clinically treating connective tissue disease in acute stages . a marked inhibition effect of hydrocortisone is shown on day 1 ; however , the effect reduces after day 10 . 0 . 5 % carboxymethylcellulose is the excipient of hydrocortisone , and used herein as a control group . on the other hand , the initial effects of the 10 % phenylbutyrate cream and 1 % trichostatin a ointment are not obvious , but 40 % and 50 % of inhibition are observed since day 10 , and even 31 % and 41 % of inhibition are maintained on day 15 , respectively . there is a dose response relationship in phenylbutyrate since the 1 % of phenylbutyrate cream is not as effective as the 10 % cream . referring to table 2 , the systematic inhibition effect of hydrocortisone is partially shown in delayed phase ( i . e . left paw ), while that of the phenylbutyrate and trichostatin a are not significant . the results indicate that the topical formulations of the invention have local rather than systematic efficacy , which is useful in the topical application to external regions . fig5 a - 5 f are photographs showing treatment with 10 % of phenylbutyrate cream or 1 % trichostatin ointment induces accumulation of acetylated histones in vivo . on day 1 and day 15 , the soft tissues from connective tissue disease treated with phenylbutyrate or trichostatin a are shown to have increased acetylated h3 by immunofluorescence ( santa cruz ). fig6 a - 6 p are photographs showing that phenylbutyrate and trichostatin a have similar effects on suppression of the connective tissue disease . the left panel is the vehicle group , and the right panel is the treated group . fig6 a and 6b are lateral views of ankle and plantar joints . comparison of the lateral views shows suppression of the swelling of ankle and plantar joints in the treated group . fig6 c and 6d are back views of ankle and plantar joint . healing is promoted in the plantar skin wound in the treated group . this skin wound resulted from killed mycobacterium tuberculosis injected into the sub - plantar region to produce connective tissue disease . fig6 e and 6f are cross - sections ( sagittal cut ). the joint structure in the paw is swollen and deteriorated in the vehicle group but preserved in the treated group . fig6 g and 6h are micro - sections confirming that panus formation is prevented , soft tissue swelling is decreased , and the joints are preserved in the treated group . fig6 i and 6j are histology ( 40 ×) showing severe synovial hyperplasia , pannus formation and joint destruction in the vehicle group but only moderately synovial hyperplasia is noted and no pannus is formed in the treated group . fig6 k and 6l are higher magnification ( 100 ×) to demonstrate that the cartilage and bone are deteriorated in the connective tissue disease but preserved after treatment with histone deacetylase inhibitors . fig6 m and 6n are histology ( 40 ×) and the vehicle group shows severe dermal swelling , subcutaneous thick fibrosis with microabscess formation and diffuse lymphocyte infiltration , but the treated group shows normal dermal structure with only small focal lymphocyte aggregation without swelling . fig6 o and 6p are higher magnification ( 100 ×). the vehicle group shows diffuse lymphocyte infiltration and fibrosis in subcutaneous tissue . the treated group only shows focal lymphocyte aggregation , and the muscle bundles and connective tissues are still distinguishable . as shown in table 2 and fig7 a - 7 f , trichostatin a with 1 % ointment is more potent than phenylbutyrate with 10 % cream . the lymphocyte infiltration , soft tissue swelling and synovial hyperplasia are suppressed more effectively in the 1 % trichostatin a ointment treated group than in the 10 % phenylbutyrate cream treated group . effect of phenylbutyrate inhibitors on the cell cycle regulator in the inflamed invasive synovium of connective tissue disease . fig8 a - 8 f are from lower magnification to higher magnification showing the results of h & amp ; e stain ( left panel ), and immunohistochemistry ( right panel ) which was performed to demonstrate that the cell cycle inhibitor , p16 , is upregulated in the synovium of connective tissue disease , and pannus formation is blocked after the phenylbutyrate treatment although there is still some lymphocyte infiltration in the synovium . fig8 g - 5 l are from lower magnification to higher magnification showing the severe synovial hyperplasia and panus formation in connective tissue disease deteriorating the cartilage and bone of joints ( left panel : h & amp ; e stain ). in contrast , there is no p16 staining in the invasive synovium of the vehicle group when compared to the synovium in the treated group ( right panel : immunohistochemistry ). the results demonstrate that phenylbutyrate can induce cell cycle arrest in the synovial fibroblasts of connective tissue disease to prevent pannus formation and joint destruction . effect of phenylbutyrate on the proinflammatory mediator in the connective tissues of connective tissue diseases . fig9 a - 9 j show that tnf - a is widespread in the connective tissue disease with inflammation of skin , subcutaneous tissues and joint in the vehicle group but only small amount of tnf - α was stained in the skin in the phenylbutyrate - treated group . this result indicates that phenylbutyrate can suppress the proinflammatory mediator , tnf - α , in the connective tissues ( including synovium lining the joint , subcutaneous tissue , dermis , and epidermis ) of connective tissue disease . moreover , trichostatin a also has the same effects on upregulation of p16 and downregulation of tnf - α as phenylbutyrate . as shown in fig1 a , trichostatin a upregulates p16 expression in the thin synovium lining the joint space . in contrast , there is no tnf - α staining in soft tissues in the connective tissue disease after trichostatin a treatment ( 10 b ). referring to examples 4 and 5 , phenylbutyrate and trichostain a simultaneously coordinate upregulation of a cell cycle inhibitor , p16 , and downregulation of an inflammatory mediator , tnf - α , in connective tissue disease . this result suggests that histone deacetylase inhibitors are effective for the treatment of connective tissue diseases of which cell cycle has dysregulation , and proinflammatory cytokine aberrant response are characteristics . the results in the present invention indicate that histone deacetylase inhibitors provide a novel therapeutic potential in the treatment of connective tissue diseases consisting of rheumatoid arthritis , systemic lupus erythematosus , progressive systemic sclerosis , sjogren &# 39 ; s syndrome , dermatomyositis , and mixed connective tissue disease with inflammation of skin , joints , and soft tissues due to altered patterns of immunoregulation as autoimmune disorders . in conclusion , at least two unrelated histone deacetylase inhibitors are active compounds for the treatment of connective tissue diseases . the present invention also relates to a method for the treatment of humans or animals afflicted with connective tissue diseases , comprising administering to the subject an effective amount of a histone deacetylase inhibitor in particular trichostatin a and phenylbutyrate or a pharmaceutically acceptable salt thereof and optionally a suitable excipent . all of the features disclosed in this specification may be combined in any combination . each feature disclosed in this specification may be replaced by an alternative feature serving the same , equivalent , or similar purpose . thus , unless expressly stated otherwise , each feature disclosed is only an example of a generic series of equivalent or similar features . from the above description , one skilled in the art can easily ascertain the essential characteristics of the present invention , and without departing from the spirit and scope thereof , can make various changes and modifications of the invention to adapt it to various usages and conditions . for example , compounds structurally and functionally analogous to histone deacetylase inhibitors described above can also be used to practice the present invention . thus , other embodiments are also within the claims .
compounds of a histone deacetylase inhibitor . the compounds are capable of simultaneously modulating cell cycle - related gene expression and inflammatory cytokine production , and are useful as anti - inflammatory agents in connective tissue disease resulting from altered patterns of immunoregulation . the present invention provides methods of treating , preventing or ameliorating connective tissue diseases , which share common features including inflammation of skin , joints and soft tissues as well as altered patterns of immunoregulation , by administering a therapeutically effective amount of a histone deacetylase inhibitor .