Equine Hoof Canker: Cell Proliferation and Morphology

Abstract

Hoof canker is described as progressive pododermatitis of the equine hoof with absent epidermal cornification and extensive proliferation of the dermal papillary body; however, in-depth research on the type of proliferative activity has not yet been reported. The aim of the present study was to determine cell-specific proliferation patterns together with morphological analysis of hoof canker tissue.Tissues removed during surgery from 19 horses presented for treatment of canker were compared to similar postmortem tissues of healthy hooves of 10 horses.Morphological alterations visible in light microscopy were assessed semiquantitatively and graded for severity. Proliferative activity was evaluated by means of anti-PCNA (proliferative cell nuclear antigen) and anti-Ki67 immunohistochemistry.Histologically, canker tissue showed five major morphological alterations, the presence of lacunae, vacuoles, giant cells, hemorrhage and inflammation, not seen in control tissue. Also, there was a notable koilocytotic appearance of keratinocytes in canker tissue. Immunohistochemistry revealed increased levels of PCNA protein expression in keratinocytes and fibroblasts of canker tissue compared to control tissue. In control tissue, keratinocytes showed higher levels of Ki67 compared to canker tissue, while the dermal fibroblasts of both groups showed similar levels of Ki67, indicating similar proliferative activity of less than 3% of total dermal fibroblasts.These results demonstrate that, in contrast to previous reports, there is no evidence for increased proliferative activity of the dermal papillary body associated with hoof canker. Increased levels of PCNA protein expression and morphological alterations indicate dysregulation of keratinocyte differentiation constitutes a key event in equine hoof canker development. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 3,9,19,20,28 However, for any of these, a causal association with the development of disease remains to be established. Morphological studies of hoof canker tissues are rare. 24, 26Ballooning of the keratinocytes, mainly in the Stratum germinativum of the frog, has been reported together with the occurrence of perinuclear vacuoles in the cells of deep layers of the Stratum spongiosum; the cells of the corium are covered by a thin layer of defective epidermis, leading to an increased risk of infection and bleeding. 26To our knowledge, the proliferative character of canker has not yet been analyzed in detail. Immunohistochemistry allows characterization of tissue proliferation, as has been shown in a number of potentially metaplastic or neoplastic tissues. 4,1...

The Presence of Treponema spp. in Equine Hoof Canker Biopsies and Skin Samples from Bovine Digital Dermatitis Lesions

“…However, it has also been reported in horses with well-maintained hygienic conditions [6]. Microorganisms such as fungi, anaerobic bacteria, viruses, especially bovine papillomavirus, as well as genetic predisposition and autoimmune reactions are involved in the development of this disease [7]. The presence of Treponema spp.…”

“…The pathognomonic condition of equine hoof canker (pododermatitis chronic verrucosa) has a very similar clinical course, clinical signs and pathological appearance to BDD [6]. It endangers the use and welfare of horses due to the instability of the affected hoof capsule and the subsequent lameness [7]. This disease is described as an infectious process that is characterized by chronic, hypertrophic, moist subdermatitis which affects the hornproducing tissues.…”

Equine Hoof Canker: Bovine Papillomavirus Infection Is Not Associated With Impaired Keratinocyte Differentiation

“…In such cases, koilocytes are found mainly in the parakeratotic stratum corneum, 39 whereas in canker they are localized mainly in the stratum germinativum. 3…”

Dermovilite exsudativa vegetante crônica em equino: relato de caso

“…Apesar da DEVC apresentar maior prevalência em membros posteriores de cavalos de tração, atualmente já foi constatado que ela pode estar presente em diversas raças e ocorrer em um ou mais cascos, sendo relatada em todos os quatro membros (BRANDT et al, 2011;OOSTERLINCK et al, 2011). As funções de trabalho ou lazer e o bem-estar dos animais são comprometidos devido à instabilidade desenvolvida e à claudicação nos estágios finais dessa doença (APPRICH et al, 2017;BRANDT et al, 2011).…”