Topical Treatment Using Amphotericin B and DMSO for an Atypically Located Equine Cutaneous Pythiosis

Background: Cutaneous lesions by Pythium insidiosum infection are commonly observed in horses, especially in those living at flooded environments. Equine pythiosis is characterized by the development of tumoral masses that are frequently located at distal limbs, ventral abdomen, thorax, breast and face. The lesions are usually granulomatous, serosanguineous and ulcerated, most often destroyed by self-mutilation due to the intense pruritus. The proposed treatment includes surgical excision followed by antifungal drugs administration, which can be done systemically or topically. Amphotericin B and dimethyl sulfoxide (DMSO) in association has been successfully used for cutaneous pythiosis topical treatment due to the DMSO property to carry any substance through plasmatic membranes. Case: The present report concerns a 12-year-old mixed breed gelding presenting with self-mutilation of a tumoral mass located at the left flank. The owners reported that the horse had initially presented a small wound that had evolved to a 20-cm in diameter mass in 4 weeks. Tissue samples were collected, processed and stained by the Gomori's methenamine silver (GMS) method. The histopathological analysis revealed Pythium insidiosum hyphae in a granulomatous tissue, especially located at peripheral region, where kunkers were present. Surgical excision of the mass followed by cauterization was indicated as initial treatment, and due to financial reasons, the owners elected only the topical antifungal therapy to control the fungus infection after surgery. Flunixin meglumine was also administrated for five days aiming the control of pain and inflammation. The wound was cleaned with povidone-iodine solution and rinsed with a solution containing, 50 mg, of amphotericin B in 10 mL of sterile water and 10 mL of DMSO. This procedure was carried Out twice a day. The wound healed fast due to an excellent centripetal epithelialization. and the horse was discharged after 64 days showing only 5% of the initial wound area. The owner reported by telephone the complete healing and hair growth 10 days after discharge. Discussion: Despite the atypical location of the tumoral lesion described at the present report, the history and clinical manifestations, especially the intense pruritus, showed similarity with other characteristic reports of equine cutaneous pythiosis. The diagnosis was confirmed by the histopathological examination showing hyphae structures, as described to be evidences of the presence of Pythium insidiosum in the tissue. The surgical procedure was the first step to provide remission of clinical signs, and one day after surgery the pruritus desapeared. After excision of the granulomatous tissue and cauterization, daily topical administration of amphotericin B associated with DMSO was effective in destroying the infectious agent, as observed by the excellent epithelization. A pink granulation tissue grew up providing an ideal surface for epithelial migration and the healing process progressed quickly. Centripetal epithelialization reduced the wound area until 3% of the initial area in 64 days of treatment, when the remaining wound was found almost completely healed and covered with hair. At the present report, the horse presenting pythiosis was only topically treated. The recommended therapy using amphotericin B and DMSO solution was effective, economically viable and low risk, considering that the systemic antifungal therapy usually suggested is expensive and extremely nephrotoxic. The atypical location of the lesion on the left flank shows that any anatomical region can be affected by the fungus, since the conditions for its development were present.

Expression of tlr4, md2 and cd14 in equine blood leukocytes during endotoxin infusion and in intestinal tissues from healthy horses

The expression of tlr4, md2 and cd14 was studied in equine blood leukocytes and in intestinal samples using real time PCR. The stability of three commonly used reference genes, glyceraldehyde-3P-dehydrogenase (GAPDH), hypoxantine ribosyltransferase (HPRT) and succinate dehydrogenase complex subunit A (SDHA), was evaluated using qbase(PLUS). The equine peripheral blood mononuclear cells (eqPBMC) examined were either stimulated in vitro with Phorbol 12-myristate 13-acetate (PMA) and ionomycin or with the CpG oligodeoxynuclotide 2216 (CpG-ODN 2216) or obtained from horses before, during and after infusion of endotoxin. Intestinal tissue from healthy horses was sampled at ileum, right dorsal colon and rectum. Ranking of the three reference genes used for normalisation identified the combination HPRT/SDHA as most suitable both when determined ex vivo in leukocytes obtained from experimentally induced endotoxaemia and in eqPBMC activated in vitro while HPRT/GAPDH were most appropriate for the intestinal samples. The relative amounts of mRNA for TLR4 and MD-2 increased threefold during in vitro activation of the cells with CpG-ODN 2216 but was decreased in cultures stimulated with PMA/ionomycin. A transient elevation in the transcription of tlr4 and md2 was also evident for equine blood leukocytes following endotoxaemia. The levels of mRNA for CD14 on the other hard remained unaffected both during the induction of endotoxaemia and in the in vitro stimulated PBMCs. A low steady expression of TLR4, MD-2 and CD14 mRNA was demonstrated for the intestinal samples with no variation between the intestinal segments analysed. Thus, the foundation for real time PCR based levels of analysis of mRNA for all three components in the equine LPS receptor complex in different intestinal segments was set, making it possible to carry out future expression studies on clinical material. (C) 2012 Elsevier B.V. All rights reserved.

Treatment of Pythiosis in Equine Limbs Using Intravenous Regional Perfusion of Amphotericin B

Objective To evaluate the effects of intravenous regional limb perfusion (IRLP) administration of amphotericin B in horses to treat pythiosis after surgical excision and thermocautery. Study Design Case series. Animals Horses (n = 12) with Pythium insidiosum infection of the distal aspect of the thoracic or pelvic limbs. Methods After surgical excision of granulation tissue and thermocautery, 50 mg amphotericin B was administered by IRLP through a catheter placed in a superficial vein of the affected limb next to the lesion after placing a tourniquet above the injection site. The lesions and locomotor system were evaluated before treatment and at 7, 14, 21, 28, 35, and 60 days. Results Ninety-two percent of horses treated with amphotericin B had complete lesion resolution 35 or 60 days after 1 or 2 IRLP treatments, respectively. IRLP induced limb edema and pain during regional palpation in 42%, and inflammation of the injection site in 33% of horses; however these signs resolved after 14 days. Conclusions IRLP administration of amphotericin B was effective for treating pythiosis in equine limbs, resolving infection with manageable side effects.

Do blood components affect the production of reactive oxygen species (ROS) by equine synovial cells in vitro?

Brossi P.M., Baccarin R.Y.A. & Massoco C.O. 2012 Do blood components affect the production of reactive oxygen species (ROS) by equine synovial cells in vitro? Pesquisa Veterinaria Brasileira 32(12):1355-1360. Departamento de Clinica Medica, Faculdade de Medicina Veterinaria e Zootecnia, Universidade de Sao Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87, Butanta, Sao Paulo, SP 5508-210, Brazil. E-mail: baccarin@ usp.br Blood-derived products are commonly administered to horses and humans to treat many musculoskeletal diseases, due to their potential antioxidant and anti-inflammatory effects. Nevertheless, antioxidant effects have never been shown upon horse synovial fluid cells in vitro. If proved, this could give a new perspective to justify the clinical application of blood-derived products. The aim of the present study was to investigate the antioxidant effects of two blood-derived products - plasma (unconditioned blood product - UBP) and a commercial blood preparation (conditioned blood product - CBP)(4) - upon stimulated equine synovial fluid cells. Healthy tarsocrural joints (60) were tapped to obtain synovial fluid cells; these cells were pooled, processed, stimulated with lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA), and evaluated by flow cytometry for the production of reactive oxygen species (ROS). Upon addition of any blood-derived product here used - UBP and CBP - there was a significant decrease in the oxidative burst of synovial fluid cells (P<0.05). There was no difference between UBP and CBP effects. In conclusion, treatment of stimulated equine synovial cells with either UBP or CBP efficiently restored their redox equilibrium.

Dynamics of follicular growth and progesterone concentrations in cyclic and anestrous suckling Nelore cows (Bos indicus) treated with progesterone, equine chorionic gonadotropin, or temporary calf removal

The objective of this study was to investigate the effects of eCG and temporary calf removal (TCR) associated with progesterone (P4) treatment on the dynamics of follicular growth, CL size, and P4 concentrations in cyclic (n ¼ 36) and anestrous (n ¼ 30) Nelore cows. Cyclic (C) and anestrous (A) cows were divided into three groups. The control group received 2 mg of estradiol benzoate via intramuscular (IM) injection and an intravaginal device containing 1.9 g of P4 on Day 0. On Day 8, the device was removed, and the animals received 12.5 mg of dinoprost tromethamine IM. After 24 hours, the animals received 1 mg of estradiol benzoate IM. In the eCG group, cows received the same treatment described for the control group but also received 400 UI of eCG at the time of device removal. In the TCR group, calves were separated from the cows for 56 hours after device removal. Ultrasound exams were performed every 24 hours after device removal until the time of ovulation and 12 days after ovulation to measure the size of the CL. On the same day as the CL measurement, blood was collected to determine the plasma P4 level. Statistical analyses were performed with a significance level of P ≤ 0.05. In cyclic cows, the presence of the CL at the beginning of protocol resulted in a smaller follicle diameter at the time of device removal (7.4 ± 0.3 mm in cows with CL vs. 8.9 ± 0.4 mm in cows without CL; P ¼ 0.03). All cows ovulated within 72 hours after device removal. Anestrous cows treated with eCG or TCR showed follicle diameter at fixed-timed artificial insemination (A-eCG 10.2 ± 0.3 and A-TCR 10.3 ± 0.5 mm) and follicular growth rate (A-eCG 1.5 ± 0.2 and A-TCR 1.3 ± 0.1 mm/day) similar to cyclic cows (C-eCG 11.0 ± 0.6 and C-TCR 12.0 ± 0.5 mm) and (C-eCG 1.4 ± 0.2 and C-TCR 1.6 ± 0.2 mm/day, respectively; P ≤ 0.05). Despite the similarities in CL size, the average P4 concentration was higher in the A-TCR (9.6 ± 1.4 ng/mL) than in the A-control (4.0 ± 1.0 ng/mL) and C-TCR (4.4 ± 1.0 ng/mL) groups (P < 0.05). From these results, we conclude that eCG treatment and TCR improved the fertility of anestrous cows by providing follicular growth rates and size of dominant follicles similar to cyclic cows. Additionally, TCR increases the plasma concentrations of P4 in anestrous cows

Diagnosis of rabies and eastern and western equine viral encephalitides in equids by multiplex Hemi-Nested RT-PCR technique

Financial support: CNPq and Pasteur Institute of São Paulo