Process for implementing in vitro spermatogenesis and associated device

1. A method for in vitro spermatogenesis from male testicular tissue comprising:

(a) conducting maturation of testicular tissue in a bioreactor which is made of a biomaterial and comprises at least one cavity wherein the testicular tissue is confined, said bioreactor being placed in or in the contact of a culture medium until elongated spermatids and/or spermatozoa are produced; and

(b) recovering said elongated spermatids and/or spermatozoa,

wherein said cavity is closed during the maturation process,

wherein the bioreactor has a permeability that enables sufficient gas exchange and metabolite circulation between the culture medium and the cavity, and the biomaterial being a hydrogel that enables air, carbon dioxide, and the elements of the culture medium into which the bioreactor is placed for maturation to diffuse through it; and

wherein the testicular tissue comprises germ cells, Sertoli cells and peritubular cells, where the germ cells are in close association with Sertoli cells.

2. The method according to claim 1 , wherein the testicular tissue comprises at least one seminiferous tubule or fragments of at least one seminiferous tubule.

3. The method according to claim 2 , wherein the testicular tissue comprises fragments from 2 to 50, 3 to 40, 4 to 30, or 5 to 20 seminiferous tubules.

4. The method according to claim 2 , wherein the tubules and/or fragments are obtained through mechanical separation or enzymatic separation of seminiferous tubules.

5. The method according to claim 2 , wherein the fragments of seminiferous tubules have a length between about 1 mm and about 5 mm.

6. The method according to claim 1 , wherein the testicular tissue further comprises Leydig cells.

7. The method according to claim 1 , wherein cells selected from the group consisting of germ cells, Sertoli cells, peritubular cells and mixtures thereof, are added to the testicular tissue.

8. The method according to claim 1 , wherein the volume of the cavity or the volume of testicular tissue is from about 1 to about 100 mm 3 , from about 0.5 to about 150 mm 3 , or from about 1 to about 30 mm 3 .

9. The method according to claim 1 , wherein the testicular tissue is obtained from a subject selected from the group consisting of:

a healthy prepubertal or postpubertal patient about to undergo a gonado-toxic treatment or surgery;

a postpubertal patient who does not produce spermatozoa due to genetic or acquired non-obstrusive azoospermia, bilateral chryptorchidism during childhood or severe sickle cell disease;

a prepubertal patient having bilateral chryptorchidism or severe sickle cell disease;

endangered species;

a horse, a camel, a dromedary or a pet; and

livestock.

10. The method according to claim 1 , wherein the biomaterial comprises collagen.

11. The method according to claim 1 , wherein the biomaterial comprises a natural polysaccharide selected from the group consisting of chitosan, hyaluronic acid, alginate, pectin and a modified natural polysaccharide, and wherein said natural polysaccharide is used alone or in a mixture.

12. The method according to claim 1 , further comprising:

i) providing a sample of testicular tissue comprising germ cells, Sertoli cells and peritubular cells, where the germ cells are in close association with Sertoli cells;

ii) providing a bioreactor which is made of a biomaterial and comprises at least one cavity, said bioreactor having a permeability that enables sufficient gas exchanges and metabolite circulation between the culture medium and the cavity comprising the testicular tissue, and the biomaterial being a hydrogel that enables air, carbon dioxide, and the elements of the culture medium into which the bioreactor is placed for maturation to diffuse through it;

iii) introducing said testicular tissue into the at least one cavity of said bioreactor and sealing the bioreactor; and

iv) placing said bioreactor containing said testicular tissue in a tank comprising a culture medium.

13. The method according to claim 1 , wherein the bioreactor is formed around the testicular tissue during the formation of the bioreactor.

14. The method according to claim 1 , wherein the bioreactor is a hollow fiber of a biomaterial comprising a channel wherein the testicular tissue is confined.

15. The method according to claim 1 wherein:

the culture medium comprises a material selected from the group consisting of growth factors, hormones, testosterone, vitamins, antibiotics, metabolites, and mixtures thereof

the culture medium comprises a material selected from the group consisting of growth factors, hormones, vitamins, antibiotics, metabolites, and mixtures thereof.

16. The method according to claim 1 wherein:

the culture medium comprises a material selected from the group consisting of growth factors, hormones, vitamins, antibiotics, metabolites, and mixtures thereof.

17. The method according to claim 1 , wherein the thickness of the biomaterial is from about 0.1 to 10 mm.

18. The method according to claim 1 , wherein testosterone is added in the culture medium during the course of the process.

19. The method according to claim 1 , wherein the biomaterial is chitosan.

20. The method according to claim 1 , wherein the bioreactor is a hollow fiber of chitosan comprising a channel wherein the testicular tissue is confined.

21. Process of in vitro fertilization comprising:

a) preparing of elongated spermatids and/or spermatozoa according to the process of claim 1 ; or providing elongated spermatids and/or spermatozoa by the process according to claim 1 ; and

b) fertilizing of an oocyte with the elongated spermatids and/or spermatozoa obtained.