Pathogenetic studies on feline eosinophilic granuloma complex

Descripció del recurs: el 12 de juliol de 2004En el gat, encara que amb freqüència es parla dels desordres associats a eosinòfils, inclòs el EGC, són poc coneguts i en general s'associen a causes immuno-mediades o parasitàries, anàlegs als seus equivalents humans. Tot i així, el contingut i les funcions dels eosinòfils dels gats, encara que es consideren similars als eosinòfils humans, no es coneixen. Per tot això, els objectius d'aquesta tesi varen ser estudiar el EGC felí i obtenir informació específica de la biologia dels eosinòfils del gat. En aquesta tesi, es varen estudiar els signes histopatològics de les diferents lesions clíniques del EGC amb seccions de H & E i tinció tricròmica. A H & E, totes les lesiones del EGC examinades es varen caracteritzar per un infiltrat dèrmic eosinofílic, de intensitat variable, i per la presència de petits a grans focus de material eosinofìlic que amb la tinció tricròmica, semblaren estar constituïts per fibres de col·lagen normals rodejades per restes de material amb el mateix aspecte tintorial dels grànuls dels eosinòfils. Aquests resultats indiquen que les lesiones del EGC amb diferent aspecte clínic histopatològicament són indistingibles i que els focus dèrmics de material eosinofílic, petits i grans, tenen una histogènesi similar. A més, les figures amb flama, utilitzades per definir petits focus de material eosinofílic amb analogia amb les figures amb flama de la síndrome de Wells, es poden utilitzar també per parlar de dipòsits de material eosinofílic de gran tamany. A més, es va investigar la ultraestructura de les figures en flama, petites i grans, de les lesions del EGC. Estan formades per fibrilles de col·lagen morfològicament inalterades, fibres de col·lagen parcialment separades per edema i restes cel·lulars i eosinòfils desgranulats via ECL i PMD. La ultraestructura de les figures en flama al EGC va ser similar al que es descriu a les figures en flama de la síndrome de Wells humana. Això suggereix que en el gat els eosinòfils juguen un paper primari en la formació de les figures en flama, anàlogues a les descrites als humans. A més, aquest estudi demostra que al EGC felí, en els teixits, els eosinòfils alliberen el contingut dels seus grànuls per ECL i PMD, igual que els eosinòfils tisulars humans en inflamacions mediades per eosinòfils. El mecanisme de desgranulació predominant va ser ECL. Es va realitzar un estudi ultraestructural de eosinòfils circulants de gats amb diferents recomptes de eosinòfils i diferents malalties asociades a eosinofília. Als eosinòfils perifèrics es va observar morfologia de PMD, indicativa d'activació i desgranulació. No es va observar correlació directa entre en numero de eosinòfils que presentaven canvis de PMD i el nivell de eosinofília sanguínia. Aquesta última observació suggereix que el recompte del número total de eosinofils circulants no representa el millor criteri per avaluar la participació dels eosinòfils en una malaltia eosinofílica. Finalment, es va realitzar un estudi sobre les proteïnes dels grànuls dels eosinòfils del gat. Es varen estudiar les proteïnes dels grànuls extretes de eosinòfils obtinguts per inducció experimental de eosinofilia peritoneal. Les proteïnes es varen analitzar per cromatografia de gel-filtració i es varen estudiar les seves activitats biològiques. Les proteïnes dels grànuls dels eosinòfils del gat tenen activitats peroxidasa, RNasa i bactericida. La EAR felina presenta una homologia de la seqüència N-terminal amb les proteïnes de la superfamília de la RNasa A, incloses les RNases de eosinòfils i la seqüència N-terminal de la MBP felina va ser homòloga a la de la MBP-1 humana i murina. Aquest resultats indiquen que les proteïnes dels grànuls del eosinòfil felí tenen un paper biològic similar als descrits als humans i a altres espècies animals i evidencien que el gat pot ser una espècie adequada per l'estudi de les malalties eosinofíliques humanes.Despite being commonly reported, feline eosinophil-associated disorders, including EGC, are poorly understood and generally associated to immune-mediated or parasitic causes, analogous to their human counterparts. Nevertheless, cat eosinophil functions and contents, although considered similar to those of human eosinophils, are currently unknown. Hence, the objectives of this thesis were to study feline EGC and to obtain specific information on the cat eosinophil biology. In this thesis, the histopathological features of clinically different EGC lesions were studied on H & E and trichrome stained sections. With H & E stain, all the EGC lesions examined were characterised by a dermal eosinophilic infiltration of variable intensity and the presence of small- to large-sized foci of eosinophilic debris that, with trichrome stain, appeared to consist of normally stained collagen fibres surrounded by a debris showing the same tinctorial properties as eosinophil granules. These results showed that EGC lesions with different clinical appearance are histopathologically indistinguishable and that small- and large-sized dermal foci of eosinophilic debris have similar histogenesis. Hence, the term flame figures, normally used to define small foci of eosinophilic debris by analogy with flame figures in Wells' syndrome, may be employed also to designate large-sized focal depositions of this debris. Furthermore, the ultrastructure of small- and large-sized flame figures in EGC lesions was investigated. They comprised morphologically unaltered collagen fibrils, collagen fibres partly disrupted by oedema and cellular debris, and degranulating eosinophils via ECL and PMD. The ultrastructure of flame figures in EGC was similar to that reported in flame figures of human Wells' syndrome. This suggested that eosinophils play a primary role in flame figures formation in cats, analogous to what reported in humans. In addition, this study demonstrated that tissue eosinophils in feline EGC release their granule contents by ECL and PMD, analogous to human tissue eosinophils at sites of eosinophil-mediated inflammation. ECL was the predominant mode of degranulation. An ultrastructural study of feline circulating eosinophils from cats with various blood eosinophil counts and different eosinophil-associated diseases was also performed. PMD morphology, indicative of eosinophil activation and degranulation, was recognised in peripheral eosinophils. No direct correlation was found between the number of eosinophils showing PMD changes and the level of blood eosinophilia. This latter finding suggested that total blood eosinophil count might not represent the best criterion to evaluate the contribution of eosinophils to the ongoing eosinophil-associated disease. Finally, a study on cat eosinophil granule proteins was conducted. Granule proteins, extracted from cat eosinophils obtained by experimentally induced peritoneal eosinophilia, were analysed by gel-filtration chromatography and their biological activities were studied. Cat eosinophil granule proteins possessed peroxidase, RNase and bactericidal activities. Feline EAR showed N-terminal sequence homology with proteins of the RNase A superfamily, including eosinophil RNases, and the N-terminal sequence of feline MBP was homologue to that of human and murine MBP-1. These findings indicated that feline eosinophil granule proteins have biological roles similar to those reported in humans and other animal species and highlighted that the cat might represent a suitable species for studying human eosinophil-mediated diseases

Clinical and Clinico-Pathological Observations of the Erythrocyte Sedimentation Rate in Dogs Affected by Leishmaniosis and Other Inflammatory Diseases

The erythrocyte sedimentation rate (ESR) has been used in canine medicine in several disorders, above all, to evaluate levels of inflammation. This study evaluated the ESR in canine leishmaniosis (CanL) and other inflammatory conditions. Three groups of dogs were examined: CanL affected dogs without clinical signs (INFECTED group, #25) or with clinical signs (SICK group, #43) and dogs affected by acute or acute-on-chronic conditions (OTHER DISEASE group, #65). The ESR was compared with acute phase proteins or reactants either positive or negative (leukogram, fibrinogen, iron, unsaturated iron binding capacity, ferritin, haptoglobin, and albumin) and immunological markers (gamma-globulins, IgG, and IgM). The ESR was higher in the SICK group than in the INFECTED group (median 39 vs. 11 mm/h; p 0.05). The extent of changes in ESR can help to establish the severity of CanL and other inflammatory disorders. As a point-of-care test, the ESR can be used to screen dogs for unhealthy conditions, and its values correlate with the severity of any disease, including CanL

Prevenzione della leishmaniosi canina: Cosa è utile sapere prima di raccomandare un prodotto topico attivo contro la puntura dei flebotomi?

In questo articolo vengono presi in esame gli ectoparassiticidi per uso topico attualmente disponibili in Italia utili per proteggere i cani dalla puntura dei flebotomi e quindi prevenire la trasmissione di Leishmania. Al medico veterinario che opera in attività correlate con la prevenzione della leishmaniosi canina vengono fornite informazioni scientifiche e pratiche relative ai seguenti ambiti: i) principi attivi e meccanismi d’azione di questi ectoparassiticidi; ii) criteri di valutazione dell’efficacia; iii) prodotti disponibili; iv) loro applicazione e v) potenziale tossicità ed effetti avversi

Cutaneous Pythiosis in 2 Dogs, Italy

We report cutaneous pythiosis in 2 dogs in Italy that had recurrent exposure to the same freshwater habitat. Phylogenetic analysis placed the isolates within Pythium insidiosum complex cluster IV, corresponding to P. periculosum. In Italy, pythiosis should be considered in differential diagnoses by human and veterinary health professionals

Pelodera strongyloides in the critically endangered Apennine brown bear (Ursus arctos marsicanus)

Skin biopsies from 20 Apennine brown bears (Ursus arctos marsicanus), 17 of which displaying skin lesions, were investigated by histopathology. Different degrees of dermatitis characterized by folliculitis and furunculosis accompanied by epidermal hyperplasia and epidermal and follicular hyperkeratosis were detected. In the most severe lesions, probably self induced by scratching, the superimposition of traumatic lesions was observed. In 8 out of 17 bears (47.0%) of affected bears, cross- and longitudinally-sectioned nematode larvae within the lumen of hair follicles were present, whose localization and morphological characteristics were consistent with Pelodera strongyloides. P. strongyloides is a free-living saprophytic nematode whose third-stage larvae can invade the skin causing pruritic dermatitis in several mammalian species. This is the first report of Pelodera infection in the brown bear. Although capable of causing primary dermatitis, the finding of Pelodera is not sufficient to conclude that it is the cause of the lesions observed in bears. Nevertheless, the high prevalence of the infection is indicative of a diffuse phenomenon that requires further specific investigations given the interest and conservational relevance of this relict bear population

Canine leishmaniasis : guidelines for diagnosis, staging, therapy, monitoring and prevention. Part I: diagnostic approach and classification of the patient affected by leishmaniasis and management of dogs with proteinuria

The "Canine Leishmaniasis Working Group"(CLWG) has elaborated guidelines for the diagnosis of canine leishmaniasis, its classification and the treatment of affected dogs with concurrent proteinuria. The guidelines are based on existing references and/or the experience of the CLWG members. The paper aims to provide the most updated information about the treatment of dogs affected by leishmaniasis. The veterinary clinician should critically evaluate the potential applicability of the present guidelines when treating cases of canine leishmaniasis