Temporal expression of inflammatory mediators in brain basilar artery vasculitis and cerebrospinal fluid of rabbits with coccidioidal meningitis

Animal models of invasive mycoses

Animal models of invasive fungal infections have been developed and are applied in a huge number of different animal species for a number of research purposes, for example, the study of pathogenesis, defense mechanisms, and therapeutic strategies. From the different models, which in most cases are based on the same fungal species and often the same strain, as in spontaneous human infections, fundamental results and knowledge of the diagnosis, progression, prophylaxis, and therapy have been achieved. However, in all models, one should be critical with respect to mimicking the disease entity of humans, which is often the focus of the research. In many of the models for instance, the time course is different to the one of humans, and in others, the propensity for localization and containment in specific organs does not parallel the situation in humans. Nevertheless, many animal models of invasive mycoses have proven valuable in a number of research areas. With regard to new generations of anti-mycotic drugs, the models play an essential role in demonstrating antifungal activity, as well as in demonstrating the absence of toxic side effects, a critical step which cannot be accomplished by in vitro studies.

Adjunctive Corticosteroid Therapy in the Treatment of Coccidioidal Meningitis

Coccidioidal meningitis (CM) has high morbidity, and adjunctive measures to improve outcomes are needed. Using an established multicenter retrospective cohort study of CM (N = 221), we found that patients receiving adjunctive corticosteroids had a significant reduction in secondary cerebrovascular events (P = .0049). Those with CM-associated cerebrovascular events (8%) may benefit from short-term corticosteroids.

PEDF plus DHA modulate inflammation and stimulate nerve regeneration after HSV-1 infection

Herpes simplex virus type-1 (HSV-1) infection leads to impaired corneal sensation and, in severe cases, to corneal ulceration, melting and perforation. Here, we explore the potential therapeutic action of pigment epithelial-derived factor (PEDF) plus docosahexaenoic acid (DHA) on corneal inflammation and nerve regeneration following HSV-1 infection. Rabbits inoculated with 100,000 PFU/eye of HSV-1 strain 17Syn+ were treated with PEDF + DHA or vehicle. PEDF + DHA treatment resulted in a biphasic immune response with stronger infiltration of CD4+T cells, neutrophils and macrophages at 7-days post-treatment (p.t.) that was significantly decreased by 14 days, compared to the vehicle-treated group. Screening of 14 immune-related genes by q-PCR showed that treatment induced higher expression of IFN-γ and CCL20 and inhibition of IL-18 by 7 days in the cornea. PEDF + DHA-treated animals developed less dendritic corneal lesions, opacity and neovascularization. Corneal nerve density increased at 12-weeks p.t. with functional recovery of corneal sensation. Treatment with PEDF + DHA that was postponed by 3 weeks also showed increased nerve density when compared to vehicle. Our data demonstrate that PEDF + DHA promotes resolution of the inflammatory response to the virus and, most importantly, induces regeneration of damaged corneal nerves vital for maintaining ocular surface homeostasis.

Involvement of transforming growth factor-β3 and betaglycan in the cytoarchitecture of postoperative omental adhesions

BACKGROUND

Adhesions commonly appear in patients after abdominal surgery, with considerable individual variation in adhesion composition and severity of the repair process. Here, we address the influence of transforming growth factor (TGF)-β3 and betaglycan in this response, in relation to TGF-β1, in an adhesiogenic rabbit model.

MATERIALS AND METHODS

Omental adhesions were recovered 3, 7, 14, and 90 d after the implantation of a polypropylene mesh on the parietal peritoneum in New Zealand White rabbits. Omentum from nonoperated animals served as control. Tissue specimens were examined for TGF-β3 and TGF-β1 (Western blotting, reverse transcription-polymerase chain reaction), and TGF-β1:TGF-β3 messenger RNA and protein expression ratios were analyzed. Immunohistochemical detection of TGF-β3 and betaglycan was performed.

RESULTS

Injury to the omentum led to mobilization of TGF-β3 and betaglycan-expressing cells from milky spots. Fibrous zones in adhesions were simultaneous to the presence of TGF-β1 and the membrane-bound form of betaglycan (7-d adhesions), whereas soluble betaglycan appeared in TGF-β1-positive areas showing limited fibrosis (3-d adhesions). The elevated expression of TGF-β3 concurrent with the presence of membrane-bound form of betaglycan was observed in zones of adipose regeneration (14-d adhesions), whereas zones of fibrous consistency were negative for TGF-β3.

CONCLUSIONS

Milky spots on the omentum contain inflammatory/immune cells positive for TGF-β3, TGF-β1, and betaglycan, playing a role in the damaged omentum repair. Our observations support the contribution of TGF-β3 to tissue repair through adipose tissue regeneration and the profibrotic role of TGF-β1 and suggest that these effects on the local wound repair response could be driven by the expression of betaglycan in its soluble or membrane-bound form.

Nitrosative and oxidative stresses contribute to post-ischemic liver injury following severe hemorrhagic shock: the role of hypoxemic resuscitation

PURPOSE

Hemorrhagic shock and resuscitation is frequently associated with liver ischemia-reperfusion injury. The aim of the study was to investigate whether hypoxemic resuscitation attenuates liver injury.

METHODS

Anesthetized, mechanically ventilated New Zealand white rabbits were exsanguinated to a mean arterial pressure of 30 mmHg for 60 minutes. Resuscitation under normoxemia (Normox-Res group, n = 16, PaO(2) = 95-105 mmHg) or hypoxemia (Hypox-Res group, n = 15, PaO(2) = 35-40 mmHg) followed, modifying the FiO(2). Animals not subjected to shock constituted the sham group (n = 11, PaO(2) = 95-105 mmHg). Indices of the inflammatory, oxidative and nitrosative response were measured and histopathological and immunohistochemical studies of the liver were performed.

RESULTS

Normox-Res group animals exhibited increased serum alanine aminotransferase, tumor necrosis factor--alpha, interleukin (IL) -1β and IL-6 levels compared with Hypox-Res and sham groups. Reactive oxygen species generation, malondialdehyde formation and myeloperoxidase activity were all elevated in Normox-Res rabbits compared with Hypox-Res and sham groups. Similarly, endothelial NO synthase and inducible NO synthase mRNA expression was up-regulated and nitrotyrosine immunostaining increased in animals resuscitated normoxemically, indicating a more intense nitrosative stress. Hypox-Res animals demonstrated a less prominent histopathologic injury which was similar to sham animals.

CONCLUSIONS

Hypoxemic resuscitation prevents liver reperfusion injury through attenuation of the inflammatory response and oxidative and nitrosative stresses.

Inhibitory effects of calcitonin gene-related peptides on experimental vein graft disease

BACKGROUND

Vein graft disease is a chronic inflammatory disease and limits the long-term clinical outcome of coronary revascularization. Because calcitonin gene-related peptide (CGRP) inhibits macrophage infiltration and inflammatory mediators, we hypothesized that transfected CGRP gene would inhibit macrophage infiltration and expression of inflammatory mediators in vein graft disease.

METHODS

Autologous rabbit jugular vein grafts were incubated ex vivo in a solution of mosaic adeno-associated virus vectors containing CGRP gene (AAV2/1.CGRP) or Escherichia coli B-galactosidase gene (LacZ) or a saline solution and then interposed in the carotid artery. Expression of CGRP gene was identified by reverse transcription-polymerase chain reaction, and E. coli LacZ gene expression was identified by X-gal staining. Intima to media ratios were evaluated at postoperative 4 weeks. Macrophages were identified with CD68 antibody by immunocytochemistry. Inflammatory mediators were measured with real-time polymerase chain reaction.

RESULTS

The CGRP and LacZ gene expression were positive at postoperative 4 weeks. The intima to media ratio was significantly inhibited in the AAV2/1.CGRP group. Macrophage infiltration and expression of inflammatory mediators including monocyte chemoattractant protein-1, tumor necrosis factor-alpha, inducible nitric oxide synthase, and matrix metalloproteinase-9 were also significantly inhibited in the AAV2/1.CGRP group.

CONCLUSIONS

Transfection of AAV2/1.CGRP inhibited inflammatory mediator expression, macrophage infiltration, and neointimal hyperplasia in experimental vein graft disease.

Comparative efficacies of lipid-complexed amphotericin B and liposomal amphotericin B against coccidioidal meningitis in rabbits

In separate previous studies, we have shown that lipid-complexed amphotericin B (Abelcet [ABLC]) and liposomal amphotericin B (AmBisome [AmBi]) are efficacious against coccidioidal meningitis in rabbits. Here, we compared ABLC and AmBi directly in a coccidioidal meningitis model. Male New Zealand White rabbits were infected with 5 x 10(4) Coccidioides posadasii arthroconidia by direct cisternal puncture. Therapy with intravenous ABLC or AmBi at 7.5 or 15 mg/kg of body weight or sterile 5% dextrose water (D5W) began 5 days later. Clinical assessments were done daily; cerebrospinal fluid and blood samples were obtained on day 15 and upon euthanasia. Survivors to day 25 were euthanatized, the numbers of CFU in their tissues were determined, and histology analyses of the brains and spinal cords were done. Controls showed progressive disease, whereas animals treated with either dose of either drug showed few clinical signs of infection. All ABLC- or AmBi-treated rabbits survived, whereas eight of nine D5W-treated rabbits were euthanatized before day 25 (P < 0.0001). Numbers of CFU in the brains and spinal cords of ABLC- or AmBi-treated animals were 100- to 10,000-fold lower than those in the corresponding tissues of D5W-treated animals (P < 0.0006 to 0.0001). However, only two or fewer given a regimen of ABLC or AmBi were cured of infection in both tissues. Fewer ABLC-treated rabbits (four of eight treated with 7.5 mg/kg and five of eight treated with 15 mg/kg) than controls (nine of nine) had meningitis at any level of severity (P, 0.015 or 0.043 for animals treated with ABLC at 7.5 or 15 mg/kg, respectively). Although groups of rabbits treated with AmBi regimens did not have significantly fewer animals with meningitis than the control group (P > 0.05), ABLC and AmBi were not significantly different. In this model, intravenous ABLC and AmBi were similarly highly effective, with few clinical signs of infection, 100% survival, and significantly reduced fungal burdens among treated animals. There appeared to be little benefit in using the 15-mg/kg dosage of either formulation. There was no significant advantage of one drug over the other for this indication. Further studies are required to determine the lowest effective doses of these formulations.

Analysis of cerebrospinal fluid in healthy rabbits and rabbits with clinically suspected encephalitozoonosis

Samples of uncontaminated cerebrospinal fluid (csf) were collected from the cisterna magna of 20 healthy laboratory rabbits and 21 pet rabbits with vestibular disease and/or paresis due to clinically suspected encephalitozoonosis. In the healthy rabbits' csf the leucocyte count was <or=4 leucocytes/microl (median 1.5 microl) and the concentration of protein ranged from 0.13 to 0.31 g/l (median 0.24 g/l). In the diseased rabbits, the number of leucocytes ranged from 1 to 87/microl (median 15/microl; P<0.001), and the concentration of protein ranged from 0.31 to 1.54 g/l (median 0.79 g/l; P<0.001); a cytological evaluation showed that they had greater numbers of lymphocytes and monocytes. It was concluded that encephalitozoonosis in rabbits is characterised by lymphomonocytic pleocytosis in CSF.

Animal models: an important tool in mycology

Animal models of fungal infections are, and will remain, a key tool in the advancement of the medical mycology. Many different types of animal models of fungal infection have been developed, with murine models the most frequently used, for studies of pathogenesis, virulence, immunology, diagnosis, and therapy. The ability to control numerous variables in performing the model allows us to mimic human disease states and quantitatively monitor the course of the disease. However, no single model can answer all questions and different animal species or different routes of infection can show somewhat different results. Thus, the choice of which animal model to use must be made carefully, addressing issues of the type of human disease to mimic, the parameters to follow and collection of the appropriate data to answer those questions being asked. This review addresses a variety of uses for animal models in medical mycology. It focuses on the most clinically important diseases affecting humans and cites various examples of the different types of studies that have been performed. Overall, animal models of fungal infection will continue to be valuable tools in addressing questions concerning fungal infections and contribute to our deeper understanding of how these infections occur, progress and can be controlled and eliminated.

Expression change of interleukin-8 gene in rabbit basilar artery after subarachnoid hemorrhage

OBJECTIVE

To study the expression change of interleukin-8 (IL-8) gene in the basilar artery of rabbit and the effect of IL-8 on the development of cerebral vasospasm induced by experimental subarachnoid hemorrhage (SAH).

METHODS

Thirty five healthy Japanese White Rabbits were randomly divided into saline-control group and experimental group. The experimental group was subdivided into four groups, representing day 1, 4, 7 and 14 after the first blood injection of SAH. The delayed cerebral vasospasm (DCVS) model was established by double injection of autologous blood into the cisterna magna. The expression change of cytokine IL-8 mRNA in the basilar artery was analyzed by RTPCR.

RESULTS

The expression of IL-8 gene increased on day 4-7 after the first blood injection of SAH compared with control (P< 0.001), and decreased to normal on day 14. The expression of IL-8 gene in the SAH groups were positively correlated with the degree of basilar artery stenosis (r = 0.642, P< 0.01).

CONCLUSION

The expression level of IL-8 gene in basilar arteries was intimately associated with the degree of cerebral vasospasm, suggesting that IL-8 may play an important role in the DCVS after SAH as an immunological inflammatory factor.

Gene expression profiling of peripheral mononuclear cells in lame dairy cows with foot lesions

Lameness is a major health issue and likely the single most common cause of pain and discomfort in dairy cattle. Appropriate treatment is delayed or neglected due, in part, to lack of reliable detection. Assessment of cows with lameness is currently limited to subjective visual scoring systems based on locomotion and posture abnormalities. These systems are unreliable to detect lameness, and therefore, a large number of cows remain undiagnosed. The objective of this research was to search for potential biomarkers for lameness-associated painful inflammatory foot lesions in dairy cattle using microarray-based gene expression profiling of peripheral blood mononuclear cells (PBMC). BOTL5 microarrays spotted in duplicate with cDNA representing bovine immune response genes were interrogated with cDNA samples in an eight-array, balanced complete block design with dye swap. Samples from eight lame cows with inflammatory foot lesions and from eight sound cows were pair-matched by age, weight, days in lactation, and pregnancy status at time of PBMC collection and directly compared with each other on individual arrays. Statistical analysis of resulting fluorescence intensity data revealed 31 genes that were putatively differentially expressed in lame versus sound cows (P<0.05). Of these, BLASTn analysis and gene ontology information showed that 28 genes had high similarity or homology to known human and/or rodent genes. Validation of 15 of these genes known to be important in inflammation and pain was carried out using relative quantitative real-time RT-PCR, which confirmed the up-regulation of interleukin (IL)-2 (12.68+/-1.47-fold increase) and IL-10 (2.39+/-0.55-fold increase), matrix metalloproteinase-13 (MMP-13) (10.44+/-1.14-fold increase), and chemokine C-C motif receptor-5 (CCR5) (5.26+/-1.05-fold increase), in lame relative to sound cows (P< or =0.05). Similarly, granulocyte-macrophage colony-stimulating factor receptor alpha chain precursor (GM-CSF-R-alpha) (2.30+/-0.63-fold increase) and IL-4 (2.06+/-0.59-fold increase) showed a tendency (P=0.10) for up-regulation in lame compared to sound cows. PBMC co-expression of IL-2, MMP-13, CCR5 and IL-10, and potentially IL-4 and GM-CSF-R-alpha appears to be a promising, objective sign of lameness-related inflammatory foot lesions in dairy cattle. In conclusion, this study revealed potential biomarkers of the presence of foot lesions that could boost diagnostic accuracy of lameness and, ultimately, help identify animals in need of pain relief.

Quantitation of rabbit cytokine mRNA by real-time RT-PCR

Fundamental understanding of rabbit immunology and the use of the rabbit as a disease model have long been hindered by the lack of immunological assays specific to this species. In the present study, we sought to develop a method to quantitate cytokine expression in rabbit cells and tissues. We report the development of a quantitative real-time RT-PCR method for measuring the relative levels of rabbit IFN-gamma, IL-2, IL-4, IL-10 and TNF-alpha mRNA. Quantitation was accomplished by comparison to a standard curve generated using plasmid DNA containing partial sequences of the relevant cytokines. Experimental studies demonstrate applicability of this assay to quantitate cytokine mRNA levels from rabbit spleen cells following mitogen stimulation. We have further utilized this assay to also examine cytokine expression in rabbit tissues during experimental syphilis infection.

Experimental animal models of coccidioidomycosis

Experimental models of coccidioidomycosis performed using various laboratory animals have been, and remain, a critical component of elucidation and understanding of the pathogenesis and host resistance to infection with Coccidioides spp., as well as to development of more efficacious antifungal therapies. The general availability of genetically defined strains, immunological reagents, ease of handling, and costs all contribute to the use of mice as the primary laboratory animal species for models of this disease. Five types of murine models are studied and include primary pulmonary disease, intraperitoneal with dissemination, intravenous infection emulating systemic disease, and intracranial or intrathecal infection emulating meningeal disease. Each of these models has been used to examine various aspects of host resistance, pathogenesis, or antifungal therapy. Other rodent species, such as rat, have been used much less frequently. A rabbit model of meningeal disease, established by intracisternal infection, has proven to model human meningitis well. This model is useful in studies of host response, as well as in therapy studies. A variety of other animal species including dogs, primates, and guinea pigs have been used to study host response and vaccine efficacy. However, cost and increased needs of animal care and husbandry are limitations that influence the use of the larger animal species.

Coccidioidal Meningitis

Coccidioidal meningitis affects between 200 to 300 persons annually within the endemic area of the United States, with much larger numbers expected in epidemic years. Because this represents a chronic disease for survivors, several thousand patients may be under treatment at any given time. Epidemiology, background, and diagnosis are reviewed. Azole therapy has replaced intrathecal amphotericin B for induction and maintenance therapy for this disease, given its ease of administration and equivalent efficacy in controlling infection even at the cost of losing the opportunity for cure. Both itraconazole and fluconazole have demonstrated efficacy, but have not been compared in randomized human studies. One of the uses of intrathecal amphotericin B is as "add on" therapy in failing azole regimens without evidence of antagonism. Details of therapeutic approach are reviewed. Approach to diagnosis and management of the two principal potentially life threatening complications, hydrocephalus and vasculitis, is also discussed.