Morphological and cellular changes in secondary epidermal laminae of horses with insulin-induced laminitis

Abstract

Results indicated SEL elongation, narrowing, and alteration in orientation developed in all feet of ponies with insulin-induced laminitis. This was primarily attributable to cell stretching that developed at the same time as an accelerated cell death-proliferation cycle; differences in cell cycle responses among laminar regions between forefeet and hind feet may have been attributable to differences in load bearing.

Lamellar pathology in horses with pituitarypars intermediadysfunction

“…Axial tapering of epidermal lamellae due to cell stretching was noticed in a previous study in animals with naturally occurring hyperinsulinaemic laminitis as well as in the present study. However, in the current study, tapering was noticed also in middle regions, possibly due to more prolonged duration of laminitis (median 120 days in animals with hyperinsulinaemic laminitis vs. 12 months in the present study) . Abaxially (close to the hoof wall) the lesions were indistinguishable from the lesions of horses with naturally occurring hyperinsulinaemic laminitis .…”

“…In the current study, PEL were also wider in laminitic animals compared with other groups. This increase in PELW occurred due to an increased amount of keratin, which takes time to form, and was therefore not seen in experimental animals . Axial tapering of epidermal lamellae due to cell stretching was noticed in a previous study in animals with naturally occurring hyperinsulinaemic laminitis as well as in the present study.…”

“…The key changes denoting laminitis were PEL elongation and widening; increased tapering in axial and middle regions of PEL and increased fusion, keratinisation and separation in the abaxial and middle regions. Primary and/or secondary epidermal lamellar elongation has been shown to be a key feature of lamellar histopathology both in experimental studies and natural cases . In the current study, PEL were also wider in laminitic animals compared with other groups.…”

An update on equine laminitis

“…Experimental results have indicated a correlation of various mechanisms involved in the pathogenesis of the disease, resulting in loss of interdigitations, weakening of the laminar tissue hoof and rotation or sinking of the distal phalanx (POLLITT, 1996;RIO TINTO et al, 2004;LASKOSKI et al, 2009;KARIKOSKI et al, 2014). The main appointed mechanisms are ischemic, enzymatic, endocrine (metabolic) and inflammatory injuries.…”

“…The most severe cases of laminar injury includes total destruction of the interdigitations, with consequent weakness of the tissue, which turns not to be able to maintain the adherence of the distal phalanx to the hoof wall (POLLITT, 1996;LASKOSKI et al, 2010). Laminitis secondary to metabolic abnormalities differs in respect to histopathology of laminar tissue of the hoof, appearing subtle injury of the laminar structures (KARIKOSKI et al, 2014), and being detected even without clinical signs of disease in horses with PPID -Pituitary Pars Intermedia Dysfunction .…”