Mesenchymal stem cells have become extremely interesting for regenerative medicine and tissue engineering in the horse. Stem cell therapy has been proven to be a powerful and successful instrument, in particular for the healing of tendon lesions. We pre-differentiated equine adipose-tissue-derived stem cells (ASCs) in a collagen I gel scaffold by applying tensile strain, growth differentiation factors (GDFs) and various oxygen tensions in order to determine the optimal conditions for in vitro differentiation toward the tenogenic lineage. We compared the influence of 3% versus 21% oxygen tension, the use of GDF 5, GDF 6 and GDF 7 and the application of uniaxial tensile strain versus no mechanical stimulation on differentiation results as evaluated by cell morphology and by the expression of the tendon-relevant genes collagen I, collagen III, cartilage oligomeric matrix protein and scleraxis. The best results were obtained with an oxygen tension of 21%, tensile stimulation and supplementation with GDF 5 or GDF 7. This approach raises the hope that the in vivo application of pre-differentiated stem cells will improve healing and recovery time in comparison with treatment involving undifferentiated stem cells.

Adipose tissue-derived stem cells (ADSCs) represent a promising subpopulation of adult stem cells for tissue engineering applications in veterinary medicine. In this study we focused on the morphological and molecular biological properties of the ADSCs. The expression of stem cell markers Oct4, Nanog and the surface markers CD90 and CD105 were detected using RT-PCR. ADSCs showed a proliferative potential and were capable of adipogenic and osteogenic differentiation. Expression of Alkaline phosphatase (AP), phosphoprotein (SPP1), Runx2 and osteocalcin (OC) mRNA were positive in osteogenic lineages and peroxisome proliferator activated receptor (Pparγ2) mRNA was positive in adipogenic lineages. ADSCs show stem cell and surface marker profiles and differentiation characteristics that are similar to but distinct from other adult stem cells, such as bone marrow-derived mesenchymal stem cells (BM-MSCs). The availability of an easily accessible and reproducible cell source may greatly facilitate the development of stem cell based tissue engineering and therapies for regenerative equine medicine.

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Summary This report describes a case of an unusually extensive and invasive fungal granuloma within the right guttural pouch and its surrounding area of a 2‐year‐old Noriker gelding, causing diverse neurogenic deficits and tissue destruction. The gelding was initially presented with cachexia, unilateral nasal discharge, intermittent fever, swelling of the right side of the head, facial nerve paralysis and dysphagia. The right guttural pouch was not accessible to endoscopic examination initially, but after anti‐inflammatory medical management, empyema and an extensive, solid mass appeared within the guttural pouch. Surgical exploration and excision were attempted but were unsuccessful. Histopathological examination identified Aspergillus fumigatus as the causative infective agent of the extensive fungal granuloma, and the consequent invasion and destruction of surrounding bone and soft tissue structures.

A 22-year-old, non-pregnant, retired pasture pony was presented with severe and sudden-onset haemorrhage from the vulva. Transrectal palpation revealed a mass in the right uterine horn. Laparoscopic partial ovariohysterectomy was performed and a histopathologic examination of the tumour revealed a uterine leiomyoma. The mare recovered without complications and was discharged nine days later. Both four and eighteen months after discharge, the mare was found to be in a good general condition, enjoying her retirement without any clinical complaints.