as intended herein “ cell therapy ”, for example using gingival fibroblasts , relates to the correction of defects , for example vascular defects or skin wounds , in tissues of an individual by administering cells suitable to cure said defect to said individual . as intended herein “ healing agent ” relates to any agent who has the ability to promote , accelerate , or improve wound healing . the agent can be a compound in solution , such as a compound selected from the group constituted of growth factors and cytokines . the agent can also be a cell suspension . as intended herein a “ cell suspension ” for a cell therapy relates to a liquid composition comprising cells in a medium suitable to sustain survival and optionally growth of these cells . such media are well known to the man skilled in the art . as intended herein a “ biological conduit ” relates to any conduit which can be found in a human or an animal body which function is to conduct fluids or gases within the body . biological conduits notably encompass the vascular , digestive , respiratory or uro - genital conduits . as intended herein a “ defect of a biological conduit ” relates to a lesion or a disease of the internal wall of said conduit . as intended herein a “ hollow organ ”, or a cavitary organ , relates to any organ which comprises a cavity . hollow organs notably encompass the heart and vesicular organs , such as the biliary vesicule or the bladder . as intended herein a “ defect of a hollow organ ” relates to a lesion or a disease of the internal wall of said conduit . in particular , as intended herein a “ vascular defect ” relates to a defect of vascular walls , preferably of arterial walls , which occurs upon abnormal cicatrisation of lesions of these walls . the lesions are of various origins , such as hypoxia , lipid overload , hemodynamic factors , atheroma , or hypertension . abnormal cicatrisation notably results from disequilibrium between degradation and synthesis of the extracellular matrix , which disequilibrium induces pathological vascular remodelling . manifestations of abnormal cicatrisation particularly encompass vascular enlargement ( e . g . aneurism ), loss of elastin and vascular constriction ( e . g . stenosis , occurring in the course of atherogenesis , or restenosis , in particular post - angioplasty restenosis ). as intended herein a “ flat wound ” relates to any wound afflicting a flat surface of a tissue . flat wounds notably encompass skin wounds . as intended herein a “ skin wound ” relates to any rupture of the epidermis and / or the dermis . skin wounds according to the invention can be particularly selected from the group consisting of chronic wounds , pressure ulcers , venous ulcers , skin burns and accidental or medically - related wounds , including irradiation . furthermore skin wounds according to the invention can also be surgical wounds , i . e . wounds voluntarily made during a surgical procedure . such surgical wounds notably encompass wounds occurring in the course of plastic and reconstructive surgery or scar revision wounds ( e . g . hypertrophic scars ). the plastic and reconstructive surgery procedures according to the invention can be of any type , e . g . breast surgery , abdominal surgery , nose surgery , ear surgery , or removal of skin wounds . as intended herein , skin wounds relate to an abnormal skin formation found in genetically predisposed individuals or to the consequences of an abnormal skin development during embryogenesis , and notably comprise giant naevi , cheiloschisis , and keloids . as intended herein “ treating a flat wound ” or “ treating a skin wound ” relates to the promotion , the acceleration , or the improvement of healing at the wounded site , in particular to the formation of a functional skin at the wounded site . as intended herein a “ functional skin ” relates to skin having in particular recovered its mechanical properties and its barrier function , with respect to non - wounded skin areas . as intended herein “ gingival fibroblasts ” relate to mesenchymal cells which are capable of migrating , adhering and proliferating within the soft connective tissues of the gum , thereby maintaining the integrity of the gingival tissue which is exposed to numerous aggressions , such as mechanical stresses , bacterial infections , or ph and temperature variations . gingival fibroblasts are in particular described in gogly et al ., ( 1997 ) clin . oral invest . 1 : 147 - 152 ; gogly et al . ( 1998 ) biochem . pharmacol . 56 : 1447 - 1454 ; and ejeil et al . ( 2003 ) j . periodontol . 74 : 188 - 195 . depending on environmental conditions , gingival fibroblasts are capable to modulate their phenotype , and to respond by proliferating , migrating , synthesising matrix components or matrix - related enzymes . gingival fibroblasts synthesise collagens ( e . g . types i , iii , v , vi , vii , xii ), elastic fibers ( oxytalan , elaunin and elastin ), proteoglycans and glycosaminoglycans ( e . g . decorin , biglycan ), glycoproteins ( e . g . fibronectin , tenascin ). simultaneously , gingival fibroblasts synthesise enzymes that are able to degrade the macromolecular compounds ( matrix metelloproteinases ; mmps ), but also enzymes inhibiting active forms of mmps ( inhibitors of metalloproteinases ; timps ). gingival fibroblasts are thus important actors of extracellular matrix remodelling . procedures for taking , culturing and preserving gingival fibroblasts are well known to the man skilled in the art and are particularly described in naveau et al . ( 2006 ) j . periodontol . 77 : 238 - 47 . fig1 - 4 illustrate a first embodiment for a device according the invention , this embodiment being adapted to the treatment of vascular defects . in fig1 , 2 and 4 , a blood vessel 1 is illustrated longitudinally cut , and on fig3 , transversally cut . a healing device 2 is disposed in the internal cavity of said vessel , along a defect site thereof . the device 2 of fig1 - 4 is of a generally tubular shape . it is expandable , so as it may be moved toward the defect site of the vessel , and then expanded so that its external diameter d 2 match with the internal diameter of the vessel . of course , this external diameter may vary all along the device , as a vessel has neither a constant diameter nor a perfect circular section . the device comprises two walls 21 , 22 substantially tubular , one first wall 21 , and one wall 22 , respectively internal and external . the two walls are joined together at their common longitudinal ends , so that a cavity 24 is provided between the two walls . the cavity is suitable to contain a substance 3 with a healing agent , preferably under pressure . the internal wall 21 is tight , so that the substance 3 , shown as dots on the figures , is prevented to leak through the internal wall 21 . it can be biodegradable . on the contrary , the external wall , in a part 25 in contact with the wounded portion of the vessel , is a porous portion . this porous portion 25 is designed to let the healing agent seep through , to dispense it to the wounded area . beyond each longitudinal end of this porous portion 25 , at longitudinal ends of the external wall 22 , there are two tight portions 26 . as these thigh portions 26 are provided to be in contact with the wall 4 of the vessel , they prevent leaking , between the external wall 22 and the wall 4 , of the agent seeping through porous portion 25 . as the device 2 is substantially tubular , when in place , it allows blood flow f during treatment . then the intervention is less a trauma for the patient , and needs far less time and equipment . as particularly shown on fig1 , the device 2 can comprise a stent 6 which can be used to set the radial extension of the device , and along treatment , maintain the extension of the device . in particular , the stent 6 is designed to maintain the external wall 22 substantially in contact with the wall 4 of the vessel , even when the cavity is emptying . regarding the stent used to widen blood vessels , such a stent 6 can be of a lighter design , as less strong is needed to maintain the device 2 than to widen a vessel . these stents can be auto - expandable , for example , it can be maintained at a reduced diameter a temperature of the operating room , for example at 20 or 25 ° c ., then , using a memory of form , gain a larger diameter , the temperature of the patient &# 39 ; s body , around 37 ° c . as shown on fig2 , if not auto - expendable , the stent may be first expanded by a balloon , the remaining resilience of the stent allowing compensating the emptying of the cavity , by urging internal wall 21 toward external wall 22 . when the device is released in place , the cavity is generally empty . the device , as shown in fig4 , is then provided with means 7 to fill up the cavity . those means comprise a pipe portion 72 to connect a feeding catheter ( not shown ) and a valve 71 , to prevent leaking of substance , through the pipe portion 72 , after filling of the cavity 3 . optionally , the device can be provided with a second filling means which comprises a discharge pipe portion and a discharge valve ; when a sufficient pressure is reached in the cavity 24 the valve is designed to open , so that , in particular , an excess quantity of substance is released through the discharge pipe . fig5 and 6 illustrate a second embodiment , adapted to the healing of flat wounds , particularly of skin wounds . in this second embodiment device 2 is substantially flatly shaped . this device 2 also has one first wall 21 and one second wall 22 the two walls being joined together at their common peripheral portion 26 , so that the cavity 24 is provided between the two walls . the cavity is suitable to contain a substance with a healing agent , preferably under pressure . the first wall 21 is tight , so that the substance is prevented to leak through the first wall 21 . the second wall 22 is intended to be in contact with the flat surface 10 , while the first wall is also a protection for a wounded area 101 of the flat surface 10 against environmental aggressions . the second wall 22 comprises a porous portion 25 , in contact with the wounded area 101 , and designed to let the healing agent seep through , to dispense it to the wounded area . the porous portion 25 is surrounded by a peripheral tight portion 26 , said peripheral portion preferably having an adhesive face to maintain the porous part against the wounded area . in the flat arrangement of fig5 , the adhesive portion of the second wall is peripheral to the cavity , and its porous portion covers a whole side of the cavity . in the flat arrangement of fig6 , the adhesive portion of the second wall is disposed between the cavity and the flat surface , so that the porous portion covers only partially this side of the cavity . advantageously , the first wall is resilient , so as , when the cavity contains some substance , the first wall exert a pressure on the substance in the cavity , the pressure being sufficient for the substance to peer through the porous portion . the device , as shown in fig5 , is provided with means 7 to fill up the cavity . those means comprise first and second filling means 7 a , 7 b . the first filling means 7 a comprise a feeding pipe portion 72 to connect a feeding catheter ( not shown ) and a valve 71 , to prevent leaking of substance , through the pipe portion 72 , after filling of the cavity 24 . the second filling means 7 b comprise a discharge pipe portion 74 and a discharge valve 75 . when a sufficient pressure is reached in the cavity 24 , the valve is designed to open , so that , in particular , an excess quantity of substance is released through the discharge pipe 74 . the agent filled up in the cavity is preferably a suspension of cells . the suspension of cells can also comprise healing compounds . it is particularly preferred that the cells in suspension are gingival fibroblasts . advantageously , gingival fibroblasts have been shown to treat arterial - remodelling pathologies ( wo 2006 / 013261 ) and more recently to promote and to accelerate skin wound healing . advantageously also , gingival fibroblasts are easily sampled and cultured . besides , gingival fibroblasts possess a high expansion rate . accordingly , gingival fibroblasts provide for an almost limitless source of autologous fibroblasts . it is also preferred that the cells used for cell therapy are autologous , that is they are taken from the individual to whom they are intended to be administered . preferably the individual is a mammal and more preferably a human . however , the cells can also be allogenic , that is taken from another individual of the same species or heterologous , that is taken from another individual of another species . the number of cells in the device should preferably be of from 10 5 to 10 9 / ml . the volume of the cavity when it is filled is preferably such that the agent filled up in the cavity is under pressure , so that it tends to migrate in direction of the defect , optionally through the porous wall . preferably , the volume is of from 100 μl to 20 ml . the implantation procedure of the device of the invention will be apparent to one of skill in the art . for instance , for skin wounds , the porous wall of the device is apposed onto the wound and maintained in close contact for instance through adhesive means . as regards , the implantation of the device of the invention in vessels , one skilled in the art can for instance follow the general procedure adopted for stent implantation . briefly , a sheath is inserted in the femoral artery and then a wire is advanced through the aorta . thereafter , the catheter carrying the device is advanced over the wire until it reaches the desired site . it shall be evident to a man skill in the art , that the many arrangements and embodiments , not precisely set forth , could be practiced under the teachings of the present invention , as set forth in the following claims . for example , the use of a stent is not obligatory required . thus , the internal wall may be sufficiently resilient to expend progressively , as the cavity is emptying , thus maintaining a sufficient pressure in the cavity to cause the substance to seep through the porous portion 25 , and to maintain the internal wall 22 against the wall 4 of the vessel . preferably , the stent is made of a resorbable matter , such as polylactic acid . if not resorbable , the stent may be made of steel or nitrinol . depending on the indications , the second wall can be omitted . then the cavity is formed between the tissue and the first tight wall . in a preferred embodiment , the above - defined device is suitable for a single use only , i . e . it cannot be re - used a second time when it has already been used for cell therapy in an individual .
the present invention relates to a device for cell therapy , said device being designed to be applied on a living tissue and having at least a tight preferably biocompatible first wall , designed to form a cavity between said wall and said tissue , and further comprising means to feed a healing substance in said cavity .