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Epidermal and dermal equivalents

a technology of keratinocyte precursor and dermal fibroblast cells, which is applied in the field of epidermal and dermal equivalents, can solve the problems that the dissection of plucked anagen hairs was not required, and achieve the effects of short immobilization, reducing the concentration of allogenic or homologous serum, and reducing the risk of disease transmission

Inactive Publication Date: 2006-12-28
DFB PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0005] Prior to the disclosure of the present invention herein, the standard methodology for the generation of a primary culture of ORS keratinocytes consisted of the plucking of an anagen (i.e., growing hair shaft) hair followed by a careful microscopic dissection to remove the hair bulbs and the infundibular hair shaft. The resulting outer root sheath was then placed on the culture insert for initiation of the primary keratinocyte culture. However, numerous subsequent studies (approximately 200), wherein the anagen hair was placed directly on the culture insert without performing the initial micro-dissection to remove the hair bulbs and the infundibular hair shaft, have demonstrated that such tedious and time-consuming dissection of the plucked anagen hair was not required. This has served to markedly simplify the handling process, reduce the risk for contamination, and resulted in more efficient initiation of keratinocyte cell plating.
[0010] Yet another object of the present invention is to produce skin or epidermal equivalents using a reduced concentration of allogenic or homologous serum. This greatly mitigates the risk of disease transmission, for example, by clinical use of blood products, by the use of autologous or homologous human serum and substances derived or released from blood components (e.g., blood platelets) for supplements in in vitro culturing steps.
[0011] A further object of the present invention is a methodology which reduces the probability of mechanical damage (e.g., separation of the various constituent layers) of the skin or epidermal equivalents during transport prior to transplantation.
[0012] The clinical advantages of the methodology of the present invention, as compared to grafting techniques of chronic wounds which have been previously utilized, include, but are not limited to: noninvasiveness (so that the cells are available repeatedly), the lack of need for surgical facilities or anesthesia during the grafting procedure, and a short immobilization period of only 2 hours required following the grafting procedure.

Problems solved by technology

However, numerous subsequent studies (approximately 200), wherein the anagen hair was placed directly on the culture insert without performing the initial micro-dissection to remove the hair bulbs and the infundibular hair shaft, have demonstrated that such tedious and time-consuming dissection of the plucked anagen hair was not required.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

Preparation of ORS Cells

[0045] Keratinocyte precursor cells from the outer root sheath (ORS) of the hair follicles are selected and subsequently cultured by use of the following methodology, as disclosed in the present invention.

[0046] Approximately 40 hair follicles were plucked with tweezers from the occipital scalp of individuals, and those in the anagen phase, as detected, for example, by well-developed root sheaths, were then selected under the dissecting microscope (see e.g. Limat & Noser, 87 J. Invest. Dermatol. 485-488 (1986); Limat et al., 92 J. Invest. Dermatol. 758-762 (1989)). The anagen hair was placed directly on the microporous culture insert without performing the previously-utilized micro-dissection to remove the hair bulbs and the infundibular hair shaft.

[0047] Generally, six anagenic hairs were explanted on the microporous membrane of a cell culture insert (Costar) that carried on its undersurface a preformed feeder layer preferably comprised of 20×103 postmito...

example 2

Preparation of Epidermal Equivalents

[0052] ORS cells harvested from primary cultures were seeded at a density of 30×103 cells / cm2 to 100×103 cells / cm2, and preferably 60×103 cells / cm2, on cell culture inserts (Costar) which had been previously inoculated with 10×103 cells / cm2 to 50×103 cells / cm2, and preferably 20×103 cells / cm2, of postmitotic HDF cells on the undersurface of their microporous membrane. Similar to the culture of ORS cells, it is important to keep the HDF feeder cells in close proximity with the ORS cells, while concomitantly keeping them separated by use of the microporous membrane. This culture technique enhances proliferation, differentiation, and thus the homeostasis of the developing tissue.

[0053] Culture medium was identical that that utilized for the preparation of the primary cultures as described supra. After 72 hours, the ORS cells were exposed to air by aspiration of the liquid medium inside the insert (i.e. leaving the underside of the insert in contact...

example 3

Stabilization

[0060] Before delivery, the epidermal equivalents are “coated on-top” by placing a silicone membrane of an appropriate diameter onto the cornified upper aspect of the cultures. To further enhance stability, e.g., in case of thin and / or large epidermal equivalents, as well as to increase adhesion of the silicone membrane, a thin layer of tissue glue, e.g. fibrin glue, may be applied before.

[0061] On-top coating (1) enhances stability and improves handling of the grafts and (2) serves as a protective coat against physical damage as well as the proteolytic milieu and bacteria in the wound.

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Abstract

The present invention relates to the treatment of skin defects by organotypically-cultured autologous keratinocytes isolated from the outer root sheath of anagen or growing hair. Methods for primary, as well as subsequent organotypic cultures (i.e., epidermal equivalents) in fully-defined media supplemented by autologous human serum and substances isolated form blood components, with minimal allogeneic biological supplements, are disclosed herein. Techniques to prepare epidermal equivalents for transplantation by use of a biocompatible glue are also disclosed herein.

Description

FIELD OF THE INVENTION [0001] The invention relates to the field of cell culture of human keratinocyte precursor and dermal fibroblast cells. The invention also relates to the use of cultured keratinocyte precursor cells in the repair of skin defects by skin grafting procedures. BACKGROUND OF THE INVENTION [0002] The healing of skin defects progresses through three general phases: (i) inflammation, (ii) wound cell migration and mitosis, and (iii) extracellular matrix production and remodeling. The ordered sequence of these events is thought to be orchestrated by interactions among cells, growth factors, and extracellular matrix proteins. A crucial step of skin wound healing is epidermal regeneration (i.e., re-epithelialization). Besides interfollicular epidermal keratinocytes from the wound edges, the outer root sheath (ORS) cells from residual hair follicles also contribute to this process (see e.g., Eisen et al., 15 J. Invest. Dermatol. 145-155 (1955)). The ORS of hair follicles i...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): A61K35/36C12N5/08A61L27/00C12N11/02A61P17/02C12N5/00C12N5/071C12N5/074
CPCA61L27/3804A61L27/60A61L2430/18C12N2533/30C12N5/0628C12N5/063C12N2510/04C12N5/0627A61P17/00A61P17/02
Inventor HUNZIKER, THOMASLIMAT, ALAIN
Owner DFB PHARMA
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