Spontaneous Axonal Dystrophy in the Brain and Spinal Cord in Naïve Beagle Dogs.

Axonal dystrophy (AD) is a common age-related neurohistological finding in vertebrates that can be congenital or induced by xenobiotics, vitamin E deficiency, or trauma/compression. To understand the incidence and location of AD as a background finding in Beagle dogs used in routine toxicity studies, we examined central nervous system (CNS) and selected peripheral nervous system (PNS) tissues in twenty 18- to 24-month-old and ten 4- to 5-year-old control males and females. Both sexes were equally affected. The cuneate, gracile, and cochlear nuclei and the cerebellar white matter (rostral vermis) were the most common locations for AD. Incidence of AD increased with age in the cuneate nucleus, cerebellar white matter (rostral vermis), trigeminal nuclei/tracts, and lumbar spinal cord. Axonal dystrophy in the CNS was not accompanied by neuronal degeneration/necrosis, nerve fiber degeneration, and/or glial reaction. Axonal dystrophy was not observed in the PNS (sciatic nerve, vagus nerve branches, or gastrointestinal mural autonomic plexuses).

Modulation of the IL-33/IL-13 Axis in Obesity by IL-13Rα2.

In obesity, IL-13 overcomes insulin resistance by promoting anti-inflammatory macrophage differentiation in adipose tissue. Endogenous IL-13 levels can be modulated by the IL-13 decoy receptor, IL-13Rα2, which inactivates and depletes the cytokine. In this study, we show that IL-13Rα2 is markedly elevated in adipose tissues of obese mice. Mice deficient in IL-13Rα2 had high expression of IL-13 response markers in adipose tissue, consistent with increased IL-13 activity at baseline. Moreover, exposure to the type 2 cytokine-inducing alarmin, IL-33, enhanced serum and tissue IL-13 concentrations and elevated tissue eosinophils, macrophages, and type 2 innate lymphoid cells. IL-33 also reduced body weight, fat mass, and fasting blood glucose levels. Strikingly, however, the IL-33-induced protection was greater in IL-13Rα2-deficient mice compared with wild-type littermates, and these changes were largely attenuated in mice lacking IL-13. Although IL-33 administration improved the metabolic profile in the context of a high fat diet, it also resulted in diarrhea and perianal irritation, which was enhanced in the IL-13Rα2-deficient mice. Weight loss in this group was associated with reduced food intake, which was likely related to the gastrointestinal effects. These findings outline both potentially advantageous and deleterious effects of a type 2-skewed immune response under conditions of metabolic stress, and identify IL-13Rα2 as a critical checkpoint in adipose tissues that limits the protective effects of the IL-33/IL-13 axis in obesity.

Polyomavirus-associated Prostatitis in Wistar Han Rats Following Immunosuppression in a Chronic Toxicity Study.

Chronic prostatitis characterized on light microscopic examination by moderate, multifocal, predominantly lymphocytic inflammation associated with epithelial atypia and intranuclear and cytoplasmic inclusion-like material was identified in the prostate gland of 2 Wistar Han rats administered an immunomodulatory test article in a 6-month chronic toxicity study. Transmission electron microscopy of the prostate glands identified 45-nm, nonenveloped, icosahedral virions arranged in paracrystalline array within the cell nuclei in 1 of the 2 rats. The size, shape, location, and array pattern were most consistent with a polyomavirus. The light and electron microscopic findings after immunosuppression in our case have a resemblance to a polyomavirus recently reported to affect prostate gland epithelium in a colony of immunocompromised X-linked severe combined immune deficiency rats. To the best of our knowledge, this is the first report of light and electronic microscopic lesions in the reproductive tract associated with polyomavirus following chronic immunosuppression in a widely used, wild-type Wistar Han rat.

NK cell responses to simian immunodeficiency virus vaginal exposure in naive and vaccinated rhesus macaques.

NK cell responses to HIV/SIV infection have been well studied in acute and chronic infected patients/monkeys, but little is known about NK cells during viral transmission, particularly in mucosal tissues. In this article, we report a systematic study of NK cell responses to high-dose vaginal exposure to SIVmac251 in the rhesus macaque female reproductive tract (FRT). Small numbers of NK cells were recruited into the FRT mucosa following vaginal inoculation. The influx of mucosal NK cells preceded local virus replication and peaked at 1 wk and, thus, was in an appropriate time frame to control an expanding population of infected cells at the portal of entry. However, NK cells were greatly outnumbered by recruited target cells that fuel local virus expansion and were spatially dissociated from SIV RNA+ cells at the major site of expansion of infected founder populations in the transition zone and adjoining endocervix. The number of NK cells in the FRT mucosa decreased rapidly in the second week, while the number of SIV RNA+ cells in the FRT reached its peak. Mucosal NK cells produced IFN-γ and MIP-1α/CCL3 but lacked several markers of activation and cytotoxicity, and this was correlated with inoculum-induced upregulation of the inhibitory ligand HLA-E and downregulation of the activating receptor CD122/IL-2Rß. Examination of SIVΔnef-vaccinated monkeys suggested that recruitment of NK cells to the genital mucosa was not involved in vaccine-induced protection from vaginal challenge. In summary, our results suggest that NK cells play, at most, a limited role in defenses in the FRT against vaginal challenge.

Live simian immunodeficiency virus vaccine correlate of protection: local antibody production and concentration on the path of virus entry.

We sought design principles for a vaccine to prevent HIV transmission to women by identifying correlates of protection conferred by a highly effective live attenuated SIV vaccine in the rhesus macaque animal model. We show that SIVmac239Δnef vaccination recruits plasma cells and induces ectopic lymphoid follicle formation beneath the mucosal epithelium in the rhesus macaque female reproductive tract. The plasma cells and ectopic follicles produce IgG Abs reactive with viral envelope glycoprotein gp41 trimers, and these Abs are concentrated on the path of virus entry by the neonatal FcR in cervical reserve epithelium and in vaginal epithelium. This local Ab production and delivery system correlated spatially and temporally with the maturation of local protection against high-dose pathogenic SIV vaginal challenge. Thus, designing vaccines to elicit production and concentration of Abs at mucosal frontlines could aid in the development of an effective vaccine to protect women against HIV-1.

Adenovirus serotype 26 utilizes CD46 as a primary cellular receptor and only transiently activates T lymphocytes following vaccination of rhesus monkeys.

The cellular receptor utilized by adenovirus serotype 26 (Ad26) has remained unclear. Here we show that Ad26 transduction is CD46-dependent and is efficiently blocked by anti-CD46 but not anti-CAR antibodies, demonstrating that Ad26 utilizes CD46 as a primary cellular receptor. Moreover, following Ad26 vaccination of rhesus monkeys, we did not observe sustained activation of peripheral or mucosal vector-specific CD4(+) T lymphocytes. These data contribute to our understanding of Ad26 as a candidate vaccine vector.

Interleukin-6 neutralization alleviates pulmonary inflammation in mice exposed to cigarette smoke and poly(I:C).

Increased systemic and pulmonary levels of IL-6 (interleukin-6) are associated with the severity of exacerbations and decline of lung function in patients with COPD (chronic obstructive pulmonary disease). Whether IL-6 is directly involved or plays a bystander role in the pathophysiology of COPD remains unclear. Here we hypothesized that neutralizing circulating levels of IL-6 would modulate episodes of acute pulmonary inflammation following CS (cigarette smoke) exposure and virus-like challenges. For this purpose, we used a model where C57BL/6 mice were exposed to CS twice daily via a nose-only system, and concomitant periodic intranasal challenge with poly(I:C), a synthetic ligand for TLR3 (Toll-like receptor 3) that mimics the encounter with double stranded RNA that is carried by influenza-like viruses. This protocol recapitulates several aspects of acute pulmonary inflammation associated with COPD, including prominent airway neutrophilia, insensitivity to steroid treatment and increased levels of several inflammatory cytokines in BAL (bronchoalveolar lavage) samples. Although IL-6-deficient mice exposed to CS/poly(I:C) developed pulmonary inflammation similar to WT (wild-type) controls, WT mice exposed to CS/poly(I:C) and treated intraperitoneally with IL-6-neutralizing antibodies showed significantly lower blood counts of lymphocytes and monocytes, lower BAL levels of IL-6 and CXCL1 (CXC chemokine ligand 1)/KC (keratinocyte chemoattractant), as well as reduced numbers of BAL neutrophils, lymphocytes and macrophages. Our results thus indicate that the systemic neutralization of IL-6 significantly reduces CS/poly(I:C)-induced pulmonary inflammation, which may be a relevant approach to the treatment of episodes of acute pulmonary inflammation associated with COPD.

A protein kinase C α and ß inhibitor blunts hyperphagia to halt renal function decline and reduces adiposity in a rat model of obesity-driven type 2 diabetes.

Type 2 diabetes (T2D) and its complications can have debilitating, sometimes fatal consequences for afflicted individuals. The disease can be difficult to control, and therapeutic strategies to prevent T2D-induced tissue and organ damage are needed. Here we describe the results of administering a potent and selective inhibitor of Protein Kinase C (PKC) family members PKCα and PKCß, Cmpd 1, in the ZSF1 obese rat model of hyperphagia-induced, obesity-driven T2D. Although our initial intent was to evaluate the effect of PKCα/ß inhibition on renal damage in this model setting, Cmpd 1 unexpectedly caused a marked reduction in the hyperphagic response of ZSF1 obese animals. This halted renal function decline but did so indirectly and indistinguishably from a pair feeding comparator group. However, above and beyond this food intake effect, Cmpd 1 lowered overall animal body weights, reduced liver vacuolation, and reduced inguinal adipose tissue (iWAT) mass, inflammation, and adipocyte size. Taken together, Cmpd 1 had strong effects on multiple disease parameters in this obesity-driven rodent model of T2D. Further evaluation for potential translation of PKCα/ß inhibition to T2D and obesity in humans is warranted.

Mucosal trafficking of vector-specific CD4+ T lymphocytes following vaccination of rhesus monkeys with adenovirus serotype 5.

Post hoc analysis of the phase 2b Step study evaluating a recombinant adenovirus serotype 5 (rAd5)-based HIV-1 vaccine candidate suggested a potential increased risk of HIV-1 acquisition in subjects who were baseline Ad5 seropositive and uncircumcised. These concerns had a profound impact on the HIV-1 vaccine development field, although the mechanism underlying this observation remains unknown. It has been hypothesized that rAd5 vaccination of baseline Ad5-seropositive individuals may have resulted in anamnestic, vector-specific CD4(+) T lymphocytes that could have trafficked to mucosal sites and served as increased targets for HIV-1 infection. Here we show that Ad5-specific CD4(+) T lymphocyte responses at mucosal sites following rAd5-Gag/Pol/Nef vaccination were comparable in rhesus monkeys with and without baseline Ad5 immunity. Moreover, the total cellular inflammatory infiltrates and the CD3(+), CD4(+), HLA-DR(+), Ki67(+), and langerin(+) cellular subpopulations in colorectal and foreskin mucosa were similar in both groups. Thus, no greater trafficking of Ad5-specific CD4(+) T lymphocytes to mucosal target sites was observed following rAd5 vaccination of rhesus monkeys with baseline Ad5 immunity. These findings from this nonhuman primate model provide evidence against the hypothesis that recruitment of vector-specific target cells to mucosal sites led to increased HIV-1 acquisition in Ad5-seropositive, uncircumcised vaccinees in the Step study.

Evaluating the Sensitivity and Specificity of Promising Circulating Biomarkers to Diagnose Liver Injury in Humans.

Early diagnosis of drug-induced liver injury (DILI) continues to be a major hurdle during drug development and postmarketing. The objective of this study was to evaluate the diagnostic performance of promising biomarkers of liver injury-glutamate dehydrogenase (GLDH), cytokeratin-18 (K18), caspase-cleaved K18 (ccK18), osteopontin (OPN), macrophage colony-stimulating factor (MCSF), MCSF receptor (MCSFR), and microRNA-122 (miR-122) in comparison to the traditional biomarker alanine aminotransferase (ALT). Biomarkers were evaluated individually and as a multivariate model in a cohort of acetaminophen overdose (n = 175) subjects and were further tested in cohorts of healthy adults (n = 135), patients with liver damage from various causes (n = 104), and patients with damage to the muscle (n = 74), kidney (n = 40), gastrointestinal tract (n = 37), and pancreas (n = 34). In the acetaminophen cohort, a multivariate model with GLDH, K18, and miR-122 was able to detect DILI more accurately than individual biomarkers alone. Furthermore, the three-biomarker model could accurately predict patients with liver injury compared with healthy volunteers or patients with damage to muscle, pancreas, gastrointestinal tract, and kidney. Expression of K18, GLDH, and miR-122 was evaluated using a database of transcriptomic profiles across multiple tissues/organs in humans and rats. K18 mRNA (Krt18) and MiR-122 were highly expressed in liver whereas GLDH mRNA (Glud1) was widely expressed. We performed a comprehensive, comparative performance assessment of 7 promising biomarkers and demonstrated that a 3-biomarker multivariate model can accurately detect liver injury.

CXCL10/CXCR3 axis is associated with disease activity and the development of mucocutaneous lesions in patients with Behçet's disease.

The objective of this study was to investigate CXC chemokines and its receptor in patients with Behcet's disease (BD) and their associations with disease activity. Blood samples were collected from 109 BD patients and 36 age- and sex-matched healthy controls (HCs). Twenty-two follow-up blood samples were collected in BD patients. Serum CXC chemokines (CXCL1, CXCL8, CXCL9, CXCL10, CXCL12, CXCL13 and CXCL16) and cell surface marker expression (CD3, CD4 and CXCR3) in peripheral blood mononuclear cells (PBMCs) were assayed. Clinical features including disease activity were evaluated at the time of blood collection. CXCR3 expression in skin and intestinal lesions from BD patients and HCs was assessed via immunohistochemistry. Serum CXCL10 levels were correlated with disease activity in terms of Behçet's Disease Current Activity Form (BDCAF) (p < 0.001). In follow-up BD patients, changes in serum CXCL10 levels tended to be correlated with those of BDCAF. The percentage of CXCR3 expression in CD3-positive cells in PBMCs was inversely correlated with serum CXCL10 levels in BD patients (p = 0.022). By immunohistochemistry, the number of CXCR3-positive mononuclear cells was higher in skin and intestinal lesions of BD patients than in those of HCs. These results suggest that the CXCL10/CXCR3 axis may contribute to the pathogenesis of BD.

Multiple endocardial neurofibromas in a rosy-billed pochard (Netta peposaca).

Endocardial neoplasms are uncommon in veterinary species with most cases restricted to endocardial schwannomas in aged rats. A 15-year-old male rosy-billed pochard (Netta peposaca) was diagnosed following necropsy with numerous, proliferative endocardial masses. Histologically, these masses were composed of interlacing streams and bundles of neoplastic spindle cells supported by a fine fibrovascular stroma. Rare areas of cellular and nuclear palisading were present in the nodules. Approximately 60% of the neoplastic cells were strongly positive for S-100, whereas none of the neoplastic cells was positive for desmin, synaptophysin, neurofilament, and glial fibrillary acidic protein. The histologic features coupled with the S-100 immunoreactivity led to a diagnosis of endocardial neurofibroma.