Hyperkeratotic erythema multiforme variant in 17 dogs

BACKGROUND

A new canine subgroup defined as 'old-dog' or 'hyperkeratotic' erythema multiforme (HKEM) with marked hyperkeratosis and parakeratosis has been proposed without any detailed description of larger case series.

OBJECTIVES

We report herein the signalment, clinical signs, treatment outcome, and histopathological and immunological findings in 17 dogs with HKEM.

ANIMALS

Inclusion criteria were the presence of (i) scaly skin lesions with or without crusting; and (ii) microscopic lesions typical of EM (i.e. a panepidermal cytotoxic lymphocytic dermatitis with or without basal keratinocyte apoptosis); and (iii) microscopic ortho- and/or parakeratotic hyperkeratosis affecting the interfollicular epidermis.

MATERIALS AND METHODS

Clinical questionnaires and skin biopsies were reviewed. Polymerase chain reactions for epidermotropic viruses and direct immunofluorescence were performed.

RESULTS

Various breeds were affected with an over-representation of males in their mid-to-late adulthood (median age 9 years). Generalised skin lesions included multifocal-to-coalescing, linear and annular macules and plaques with erythema and adherent firm crusting. Microscopic lesions were specific for EM and featured prominent superficial epidermal apoptosis with lymphocytic satellitosis and parakeratosis. No drug triggers were identified. Polymerase chain reactions for canine herpesvirus polymerase gene, canine parvovirus and canine distemper virus were negative in all HKEM and canine erosive EM (15 dogs) biopsies. Lesions failed to respond to oral and/or topical antimicrobials. Complete remission of signs was achieved in 9 of 17 dogs (53%) using immunosuppressive regimens.

CONCLUSIONS AND CLINICAL RELEVANCE

Hyperkeratotic erythema multiforme (HKEM) is a chronic, persistent and clinically distinctive erythema multiforme (EM) variant that differs from 'classic' vesiculobullous erosive-to-ulcerative EM in dogs.

Spontaneous autoimmune subepidermal blistering diseases in animals: a comprehensive review

Autoimmune subepidermal blistering diseases (AISBDs) are rare skin disorders of animals that were first identified in dogs but several AISBDs are now recognised in other companion animal species. Most AISBDs in animals are homologues of the human diseases and are thought to share similar pathomechanisms of epidermal and/or mucosal blister formation caused by autoantibodies targeting structural proteins of the basement membrane zone (BMZ). Disruption of their structural function by the autoantibodies and/or recruited inflammation leads to BMZ fragility, which presents clinically as vesicles, bullae and, later, deep erosions and ulcers. Canine AISBDs are the best characterised, particularly the more common variants such as mucous membrane pemphigoid (48%), epidermolysis bullosa acquisita (EBA) (26%), and bullous pemphigoid (10%). Exceedingly rare AISBDs in the dog are junctional EBA, mixed AISBD, type-1 bullous systemic lupus erythematosus, linear IgA dermatosis, and pemphigus gestationis. The diagnosis of a specific AISBD is made by combining the clinical features (breed, age, lesion distribution) with histological evidence of subepithelial clefting, but not all AISBDs can be differentiated in this manner and specialised immunological testing is required. This latter, unfortunately, is not readily available and, therefore, the specific AISBD diagnosis often remains unconfirmed. While this limits further understanding of these diseases, it does not prevent clinicians from treating their patients, as the treatment approaches are similar for the different AISBDs in dogs. This review primarily focuses on canine AISBDs, the species for which these diseases have been best characterised, and shorter descriptions of variants in other species are also provided.

Nano-pulse stimulation™ therapy (NPS™) is superior to cryoablation in clearing murine melanoma tumors

Background

Nano-Pulse Stimulation™ Therapy (NPS™) is a new, bioelectric modality that applies ultrashort pulses of electric energy to trigger regulated cell death in treated tissues. Instead of initiating necrosis by heating or freezing, NPS therapy permeabilizes intracellular organelles to activate the cell's own self-destruct pathway of programmed or regulated cell death. Unlike cryotherapies that can both damage structural tissues and diffuse into the periphery beyond the margins of the lesion, NPS only affects cells within the treated zone leaving surrounding tissue and acellular components unaffected.

Methods

We generated melanoma tumors in mice by injecting B16-F10 cells intradermally and compared the efficacy and resulting skin damage from Nano-Pulse Stimulation Therapy with that of cryoablation in clearing these tumors.

Results

The results of the study demonstrate that NPS is superior at clearing B16-F10 melanoma lesions. NPS permanently eliminated up to 91% of all tumor lesions with a single treatment compared to cryoablation that only eliminated up to 66%. Importantly, NPS permanently eliminated these lesions with no recurrence and with minimal dermal fibrosis, underlying muscle atrophy, permanent hair follicle loss or other markers of permanent skin damage.

Conclusions

These findings suggest that NPS is a promising new modality for the clearance of melanoma tumors and is a more efficacious, less damaging approach than cryoablative methods for the treatment of aggressive malignant tumors.

Case Report: Pulmonary Conidiobolomycosis in a Vietnamese Pot-Bellied Pig

An adult castrated male Vietnamese pot-bellied pig had a 1-week history of acute dyspnea and lethargy. Minimal diagnostic testing was authorized by the owner, resulting in treatment with a third-generation cephalosporin and a non-steroidal anti-inflammatory drug. Partial improvement was observed after a week; however, the pig died 2 weeks after the initial onset of clinical signs. Macroscopically, ~90% of the left lung was effaced by large masses with a caseonecrotic center. Histologic examination revealed eosinophilic granulomas with myriad, intralesional, negatively staining hyphae highlighted by "sleeves" of hypereosinophilic material (Splendore-Hoeppli material). Infection with an oomycete or "zygomycete" (i.e., organisms of the order Entomophthorales or Mucorales) was initially considered. Pan-fungal PCR and sequencing performed on formalin-fixed, paraffin-embedded lung tissue identified Conidiobolus spp., consistent with a diagnosis of primary pulmonary conidiobolomycosis. There are only a few reports of infections with Conidiobolus spp. (and other members of the order Entomophthorales) in swine. Unlike humans and other animal species, conidiobolomycosis in pigs presents more commonly as a primary pulmonary disease rather than rhinofacial or nasopharyngeal disease.

Correlation of cytology to histology in a case of canine granulomatous colitis in a Boxer dog

A 2-year-old castrated male mixed breed dog presented to the North Carolina State Veterinary Teaching Hospital for chronic diarrhea with hematochezia and weight loss. Cytology performed on a rectal scraping revealed macrophages containing magenta, light pink, and variably blue granular inclusions, and phagocytosed material concerning for infectious organisms. Histopathology was consistent with granulomatous colitis and identified intra-histiocytic bacterial organisms, confirmed by fluorescent in situ hybridization (FISH)-tissue culture-confirmed Escherichia coli. Based on these findings, a diagnosis of granulomatous colitis was made. The patient was successfully treated with oral enrofloxacin, and near-complete remission of signs was achieved within 6 weeks. This report describes a case of granulomatous colitis in a mixed breed dog, and is the first published description of the cytologic features of this uncommon disease, offering a valuable cytologic-histologic correlation. In this case, the cytology was helpful in identifying features consistent with granulomatous colitis and prioritizing the differential diagnoses and diagnostic plan.

International Guidelines for Veterinary Tumor Pathology: A Call to Action

Standardization of tumor assessment lays the foundation for validation of grading systems, permits reproducibility of oncologic studies among investigators, and increases confidence in the significance of study results. Currently, there is minimal methodological standardization for assessing tumors in veterinary medicine, with few attempts to validate published protocols and grading schemes. The current article attempts to address these shortcomings by providing standard guidelines for tumor assessment parameters and protocols for evaluating specific tumor types. More detailed information is available in the Supplemental Files, the intention of which is 2-fold: publication as part of this commentary, but more importantly, these will be available as "living documents" on a website (www.vetcancerprotocols.org), which will be updated as new information is presented in the peer-reviewed literature. Our hope is that veterinary pathologists will agree that this initiative is needed, and will contribute to and utilize this information for routine diagnostic work and oncologic studies. Journal editors and reviewers can utilize checklists to ensure publications include sufficient detail and standardized methods of tumor assessment. To maintain the relevance of the guidelines and protocols, it is critical that the information is periodically updated and revised as new studies are published and validated with the intent of providing a repository of this information. Our hope is that this initiative (a continuation of efforts published in this journal in 2011) will facilitate collaboration and reproducibility between pathologists and institutions, increase case numbers, and strengthen clinical research findings, thus ensuring continued progress in veterinary oncologic pathology and improving patient care.

Feasibility study evaluating arrhythmogenesis and cardiac damage after heart-base irradiation in mice: A brief communication

Radiation‐induced heart disease (RIHD) is a potential cause of morbidity and mortality in dogs undergoing thoracic irradiation. Arrhythmias and sudden death have been documented in dogs undergoing stereotactic body radiation therapy for heart base tumours. A study was proposed to interrogate the effect of different stereotactic‐like radiation prescriptions on RIHD development, including arrhythmogenesis and classical histological endpoints in a mouse model. A pilot study was performed initially. The heart base of CD1 (n = 3) and C57Bl/6J (n = 3) female mice were irradiated (12 Gy × 3, daily) with a clinical linear accelerator. No significant adverse effects were noted and each mouse survived the entire subsequent 3‐month observation period. At various time points, no arrhythmias were identified on ECG analysis. Cardiac histology (haematoxylin and eosin, and picrosirius red staining) was performed at 3 months. In a single CD1 mouse and two C57BI/6J mice, multifocal, minimal, peri‐vascular lymphoplasmacytic inflammation was noted within the irradiated proximal heart. In one mouse of each strain, a small, single focus of fibrinoid vascular necrosis was observed. Overall, there was no significant myocardial necrosis, atrophy or inflammation. Picrosirius red staining revealed no evidence of fibrosis in any mouse. Dosimetric verification indicated that the irradiation was successful and delivered as planned, with an average predicted‐to‐measured dose‐difference within 5%. While this study did not demonstrate significant arrhythmogenesis, certain modifications of the experimental mouse irradiation procedures are discussed which may enable more translationally relevant modelling of the canine cardiac response to SBRT‐like irradiation.

A Subset of Equine Gastric Squamous Cell Carcinomas Is Associated With Equus Caballus Papillomavirus-2 Infection

Squamous cell carcinoma (SCC) is the most common neoplasm of the equine stomach. However, the mechanisms underlying malignant transformation are unknown. As Equus caballus papillomavirus-2 (EcPV-2) is a likely cause of some genital SCCs, we hypothesized that EcPV-2 is associated with a subset of equine gastric SCCs. To this aim, we performed polymerase chain reaction (PCR) and in situ hybridization (ISH) for EcPV-2 E6/ E7 oncogenes on 11 gastric SCCs and on gastric samples from 15 control horses with no SCC. PCR for EcPV-2 was positive in 7/11 (64%) gastric SCCs; non-SCC gastric samples were all negative. Intense hybridization signals for EcPV-2 E6/E7 nucleic acid were detected by ISH within tumor cells in 5/11 (45%) gastric SCCs, including distant metastases. No hybridization signals were detected within any of the non-SCC gastric cases. This study provides support for a potential association between EcPV-2 infection and a subset of equine gastric SCC.

C/EBPβ suppresses keratinocyte autonomous type 1 IFN response and p53 to increase cell survival and susceptibility to UVB-induced skin cancer

p53 is activated by DNA damage and oncogenic stimuli to regulate senescence, apoptosis and cell-cycle arrest, which are essential to prevent cancer. Here, we utilized UVB radiation, a potent inducer of DNA damage, p53, apoptosis and skin cancer to investigate the mechanism of CCAAT/enhancer binding protein-β (C/EBPβ) in regulating p53-mediated apoptosis in keratinocytes and to test whether the deletion of C/EBPβ in epidermis can protect mice from UVB-induced skin cancer. UVB-treatment of C/EBPβ skin conditional knockout (CKOβ) mice increased p53 protein levels in epidermis and enhanced p53-dependent apoptotic activity 3-fold compared with UVB-treated control mice. UVB increased C/EBPβ levels through a p53-dependent pathway and stimulated the formation of a C/EBPβ-p53 protein complex; knockdown of C/EBPβ increased p53 protein stability in keratinocytes. These results suggest a p53-C/EBPβ feedback loop, whereby C/EBPβ, a transcriptional target of a p53 pathway, functions as a survival factor by negatively regulating p53 apoptotic activity in response to DNA damage. RNAseq analysis of UVB-treated CKOβ epidermis unexpectedly revealed that type 1 interferon (IFN) pathway was the most highly enriched pathway. Numerous pro-apoptotic interferon stimulated genes were upregulated including some known to enhance p53 apoptosis. Our results indicate that p53 and IFN pathways function together in response to DNA damage to result in the activation of extrinsic apoptosis pathways and caspase 8 cleavage. Last, we observed CKOβ mice were resistant to UVB-induced skin cancer. Our results suggest that C/EBPβ represses apoptosis through keratinocyte autonomous suppression of the type 1 IFN response and p53 to increase cell survival and susceptibility to UVB-induced skin cancer.

Gestational diabetes alters the fetal heart rate variability during an oral glucose tolerance test: a fetal magnetocardiography study

OBJECTIVE

Gestational diabetes mellitus (GDM) potentially harms the child before birth. We previously found GDM to be associated with developmental changes in the central nervous system. We now hypothesise that GDM may also impact on the fetal autonomic nervous system under metabolic stress like an oral glucose tolerance test (OGTT).

DESIGN

We measured heart rate variability (HRV) of mothers and fetuses during a three-point OGTT using fetal magnetocardiography (fMCG).

SETTING

Measurements were performed in the fMEG Centre in Tübingen.

POPULATION

After exclusion of 23 participants, 13 pregnant women with GDM and 36 pregnant women with normal glucose tolerance were examined.

METHODS

All women underwent the same examination setting with OGTT during which fMCG was recorded three times.

MAIN OUTCOME MEASURE(S)

Parameters of heart rate variability were measured.

RESULTS

Compared with mothers with normal glucose regulation, mothers with GDM showed increased heart rate but no significant differences of maternal HRV. In contrast, HRV in fetuses of mothers with GDM differed from those in the metabolically healthy group regarding standard deviation normal to normal beat (SDNN) (P = 0.012), low-frequency band (P = 0.008) and high-frequency band (P = 0.031). These HRV parameters exhibit a decrease only in GDM fetuses during the second hour of the OGTT.

CONCLUSIONS

These results show an altered response of the fetal autonomic nervous system to metabolic stress in GDM-complicated pregnancies. Hence, disturbances in maternal glucose metabolism might not only impact on the central nervous system of the fetus but may also affect the fetal autonomic nervous system.

TWEETABLE ABSTRACT

Metabolic stress reveals a different response of fetal autonomic nervous system in GDM-complicated pregnancies.

Clinical, microscopic and microbial characterization of exfoliative superficial pyoderma-associated epidermal collarettes in dogs

BACKGROUND

The microscopic and microbial features of the spreading epidermal collarettes of canine exfoliative superficial pyodermas are poorly characterized.

OBJECTIVES

To characterize the clinical, cytological, microbial and histopathological features of epidermal collarettes in five dogs.

RESULTS

Cytology from the margins of collarettes identified neutrophils, extracellular and intracellular cocci within neutrophils but no acantholytic keratinocytes. Phenotypic and genotypic analyses identified all bacterial isolates from the centre and margin of five epidermal collarettes as Staphylococcus pseudintermedius. PCRs of collarette-associated Staphylococcus strains did not amplify genes encoding for the known exfoliative toxins expA and expB, whereas the predicted siet and speta amplification products were detected in all isolates. Microscopically, epidermal collarettes consisted of interfollicular, epidermal spongiotic pustules. Advancing edges of lesions consisted of peripheral intracorneal clefts in the deep stratum disjunctum above an intact stratum compactum; they contained lytic neutrophil debris, bacterial cocci and fluid, but no acantholytic keratinocytes. This intracorneal location of bacteria was confirmed using Gram stains and fluorescent in situ hybridization with eubacterial- and Staphylococcus-specific probes. The indirect immunofluorescence staining patterns of desmoglein-1, desmocollin-1, claudin-1, E-cadherin and corneodesmosin were discontinuous and patchy in areas of spongiotic pustules, whereas only that of corneodesmosin was weaker and patchy in advancing collarette edges.

CONCLUSION

Epidermal collarettes represent unique clinical and histological lesions of exfoliative superficial pyodermas that are distinct from those of impetigo and superficial bacterial folliculitis. The characterization of possible causative staphylococcal exfoliatin proteases and the role of corneodesmosin in collarette pathogenesis deserve further investigation.

Uterine Smooth Muscle Tumors in Potbellied Pigs (Sus scrofa) Resemble Human Fibroids: A Potential Animal Model

Uterine leiomyomas, commonly termed fibroids, clinically affect approximately 25% of women of reproductive age in the United States, with a subclinical incidence as high as 77%. The pathogenesis of fibroid formation remains poorly understood, due in large part to the lack of a suitable animal model. This retrospective study characterizes the clinical, gross, and histopathologic features of similar, spontaneously occurring uterine tumors in potbellied pigs. Medical records available through a local Potbellied Pig Spay/Neuter Program, pig sanctuaries, and the Duchess Fund database were reviewed for evidence of reproductive disease or surgery. One-hundred and six female potbellied pigs were evaluated and uterine neoplasia was identified in 17 animals; tissues were available for 13 of these. Uterine leiomyoma was diagnosed in 11 of 13 cases, leiomyosarcoma in 1 of 13 cases, and undifferentiated sarcoma in 1 case. Pigs presented with clinical signs including abdominal distension or vaginal bleeding or were subclinical and identified during ovariohysterectomy. Tumors ranged from microscopic to 45 kg, were often multiple, and primarily involved the uterine horns. Hematoxylin and eosin and trichrome-stained sections were evaluated for morphological features of human and animal leiomyomas; immunohistochemistry to detect smooth muscle actin was also performed. The cellular pattern/morphology and variable degree of fibroplasia of the leiomyomas were similar to that reported for human fibroids. These results support further investigation of uterine leiomyomas in potbellied pigs as a potentially valuable animal model for studying human fibroids.

Canine hereditary ataxia in old english sheepdogs and gordon setters is associated with a defect in the autophagy gene encoding RAB24

Old English Sheepdogs and Gordon Setters suffer from a juvenile onset, autosomal recessive form of canine hereditary ataxia primarily affecting the Purkinje neuron of the cerebellar cortex. The clinical and histological characteristics are analogous to hereditary ataxias in humans. Linkage and genome-wide association studies on a cohort of related Old English Sheepdogs identified a region on CFA4 strongly associated with the disease phenotype. Targeted sequence capture and next generation sequencing of the region identified an A to C single nucleotide polymorphism (SNP) located at position 113 in exon 1 of an autophagy gene, RAB24, that segregated with the phenotype. Genotyping of six additional breeds of dogs affected with hereditary ataxia identified the same polymorphism in affected Gordon Setters that segregated perfectly with phenotype. The other breeds tested did not have the polymorphism. Genome-wide SNP genotyping of Gordon Setters identified a 1.9 MB region with an identical haplotype to affected Old English Sheepdogs. Histopathology, immunohistochemistry and ultrastructural evaluation of the brains of affected dogs from both breeds identified dramatic Purkinje neuron loss with axonal spheroids, accumulation of autophagosomes, ubiquitin positive inclusions and a diffuse increase in cytoplasmic neuronal ubiquitin staining. These findings recapitulate the changes reported in mice with induced neuron-specific autophagy defects. Taken together, our results suggest that a defect in RAB24, a gene associated with autophagy, is highly associated with and may contribute to canine hereditary ataxia in Old English Sheepdogs and Gordon Setters. This finding suggests that detailed investigation of autophagy pathways should be undertaken in human hereditary ataxia.

Neurodegenerative diseases are one of the most important causes of decline in an aging population. An important subset of these diseases are known as the hereditary ataxias, familial neurodegenerative diseases that affect the cerebellum causing progressive gait disturbance in both humans and dogs. We identified a mutation in RAB24, a gene associated with autophagy, in Old English Sheepdogs and Gordon Setters with hereditary ataxia. Autophagy is a process by which cell proteins and organelles are removed and recycled and its critical role in maintenance of the continued health of cells is becoming clear. We evaluated the brains of affected dogs and identified accumulations of autophagosomes within the cerebellum, suggesting a defect in the autophagy pathway. Our results suggest that a defect in the autophagy pathway results in neuronal death in a naturally occurring disease in dogs. The autophagy pathway should be investigated in human hereditary ataxia and may represent a therapeutic target in neurodegenerative diseases.

Age-dependent association of serum prolactin with glycaemia and insulin sensitivity in humans

The dopamine agonist bromocriptine has been approved for the treatment of type 2 diabetes in the United States. Bromocriptine inhibits prolactin secretion, and patients with hyperprolactinaemia display impaired insulin sensitivity. We therefore hypothesized that low prolactin levels are associated with lower glycaemia and higher insulin sensitivity in healthy subjects. Prolactin levels were determined from fasting serum in participants without diabetes from the cross-sectional Tübingen family study for type 2 diabetes (m/f = 562/1,121, age = 40 ± 13 years, BMI = 30 ± 9 kg/m(2)). A 75 g oral glucose tolerance test was performed, and the area under the glucose curve (AUC(0-120)Glucose) and insulin sensitivity index were calculated. A subgroup (n = 494) underwent hyperinsulinaemic-euglycaemic clamp tests. Prolactin associated positively with insulin sensitivity (p = 0.001, adjusted for gender, age, and BMI). Age strongly interacted (p < 0.0001) with the effect of prolactin on insulin sensitivity, inverting the positive relationship to a negative one in younger participants. Glycated haemoglobin (HbA1c) and AUC(0-120)Glucose correlated negatively with prolactin, and an interaction with age was found as well. Higher prolactin levels are associated with improved insulin sensitivity and lower glucose in individuals without diabetes. This relationship turns to its opposite in younger persons. As prolactin is a proxy for the dopaminergic tone in the central nervous system, these associations may indicate an age-dependent influence of the brain on peripheral insulin sensitivity.

Cat scratch-induced Pasteurella multocida necrotizing cellulitis in a dog

BACKGROUND

In humans, rapidly developing Pasteurella multocida cellulitis after a cat scratch or bite is a well-known entity that sometimes progresses to necrotizing fasciitis and can be fatal.

CASE REPORT

A 3-year-old female spayed whippet dog developed ecchymosis, swelling and pain within 24 h of being scratched by a cat on the ventral thorax. Over the following days, while being treated only with pain medications, the lesions rapidly progressed into haemorrhagic bullae with expanding skin necrosis. A heavy growth of P. multocida was seen on bacterial cultures, and histological examination showed marked, suppurative panniculitis with necrosis of the epidermis, dermis and panniculus. Special histological stains highlighted a moderate amount of Gram-negative coccobacilli admixed with inflammatory cells. Complete resolution was achieved with surgical debridement, skin grafting and intravenous antibiotic treatment. Positive bacterial culture for P. multocida, in conjunction with the history, clinical findings, histology results and the rapid response to therapy, strongly supports a diagnosis of P. multocida necrotizing cellulitis.

CONCLUSIONS AND CLINICAL IMPORTANCE

Complications of cat bite-associated P. multocida infections in humans are well known. To the authors' knowledge, this is the first documentation of P. multocida necrotizing cellulitis in a dog following a cat scratch wound. This case highlights the rapidity and severity of P. multocida cellulitis, if not recognized and treated early. Veterinarians should include P. multocida in the differential diagnosis of any local wound infection following a cat scratch.

Thermal dose fractionation affects tumour physiological response

PURPOSE

It is unknown whether a thermal dose should be administered using a few large fractions with higher temperatures or a larger number of fractions with lower temperatures. To evaluate this we assessed the effect of administering the same total thermal dose, approximately 30 CEM43T(90), in one versus three to four fractions per week, over 5 weeks.

MATERIALS AND METHODS

Canine sarcomas were randomised to receive one of the hyperthermia fractionation schemes along with fractionated radiotherapy. Tumour response was based on changes in tumour volume, oxygenation, water diffusion quantified using MRI, and a panel of histological and immunohistochemical end points.

RESULTS

There was a greater reduction in tumour volume and water diffusion at the end of therapy in tumours receiving one hyperthermia fraction per week. There was a weak but significant association between improved tumour oxygenation 24 h after the first hyperthermia treatment and extent of volume reduction at the end of therapy. Finally, the direction of change of HIF-1α and CA-IX immunoreactivity after the first hyperthermia fraction was similar and there was an inverse relationship between temperature and the direction of change of CA-IX. There were no significant changes in interstitial fluid pressure, VEGF, vWF, apoptosis or necrosis as a function of treatment group or temperature.

CONCLUSIONS

We did not identify an advantage to a three to four per week hyperthermia prescription, and response data pointed to a one per week prescription being superior.

Insulin resistant phenotype of polycystic ovary syndrome does not seem to be caused by variation in FTO

Genetic variation in the FTO gene is associated with increased body weight and reduced insulin sensitivity. We investigated whether genetic variation in FTO is associated with polycystic ovary syndrome (PCOS), a condition also characterized by insulin resistance. Furthermore, we tested whether insulin resistance is specifically associated with genetic variation in FTO in women with PCOS. Sixty-two nondiabetic patients with PCOS defined by the Rotterdam criteria were compared to BMI and age-matched women. Each PCOS case was matched to 2 controls. All participants underwent an oral glucose tolerance test and were genotyped for the single nucleotide polymorphism rs8050136 in the FTO gene. There was no difference in the frequency of FTO genotypes between the PCOS and the non-PCOS groups. In non-PCOS participants, genetic variation in FTO is associated with insulin sensitivity (p=0.03). This association remained significant after adjustment for age and/or BMI (p<= 0.03). In subjects with PCOS, however, FTO did not associate with insulin sensitivity (p=0.67). Genetic variation in FTO does not have an impact on insulin sensitivity in women with PCOS and is therefore not involved in the pathogenesis of the insulin resistant phenotype seen in patients with PCOS.

Exercise-induced albuminuria is associated with perivascular renal sinus fat in individuals at increased risk of type 2 diabetes

AIMS/HYPOTHESIS

Microalbuminuria represents an established surrogate marker of early diabetic nephropathy and glomerular microangiopathy. Increasing evidence is emerging of a role of perivascular adipose tissue (PVAT) as an important link between obesity, insulin resistance and both macro- and microangiopathy. It is not known whether perivascular renal sinus fat (RSF) has an impact on microalbuminuria in the prediabetic stage. We investigated whether RSF quantified by MRI is associated with microalbuminuria before or after exercise.

METHODS

Non-diabetic individuals at increased risk of type 2 diabetes were recruited into the Tübingen Lifestyle Intervention Program (TULIP); 146 participants took part in the analysis. RSF was measured in axial MRI sections at the level of the renal artery. Urine was collected before and after exercise stress testing.

RESULTS

Participants (age 47 ± 12 years; mean ± SD) reached a mean exercise load of 176 ± 49 W, with a mean arterial peak pressure (MAPP) of 112 ± 14 mmHg. After adjusting for sex, age, visceral adipose tissue (VAT) and MAPP during exercise, RSF was significantly associated with postexercise albumin/creatinine ratio (ACR; p = 0.006). No association between RSF and baseline BP could be observed after adjusting for confounders (p = 0.26), and there was no association between RSF and baseline ACR either (p = 0.2).

CONCLUSIONS

RSF is associated with exercise-induced albuminuria independently of sex, age, VAT and MAPP in a non-diabetic cohort at diabetic risk. We conclude that PVAT in the renal sinus may play a role in the pathogenesis of microalbuminuria.

Nasal insulin changes peripheral insulin sensitivity simultaneously with altered activity in homeostatic and reward-related human brain regions

AIMS/HYPOTHESIS

Impaired insulin sensitivity is a major factor leading to type 2 diabetes. Animal studies suggest that the brain is involved in the regulation of insulin sensitivity. We investigated whether insulin action in the human brain regulates peripheral insulin sensitivity and examined which brain areas are involved.

METHODS

Insulin and placebo were given intranasally. Plasma glucose, insulin and C-peptide were measured in 103 participants at 0, 30 and 60 min. A subgroup (n = 12) was also studied with functional MRI, and blood sampling at 0, 30 and 120 min. For each time-point, the HOMA of insulin resistance (HOMA-IR) was calculated as an inverse estimate of peripheral insulin sensitivity.

RESULTS

Plasma insulin increased and subsequently decreased. This excursion was accompanied by slightly decreased plasma glucose, resulting in an initially increased HOMA-IR. At 1 h after insulin spray, the HOMA-IR subsequently decreased and remained lower up to 120 min. An increase in hypothalamic activity was observed, which correlated with the increased HOMA-IR at 30 min post-spray. Activity in the putamen, right insula and orbitofrontal cortex correlated with the decreased HOMA-IR at 120 min post-spray.

CONCLUSIONS/INTERPRETATION

Central insulin action in specific brain areas, including the hypothalamus, may time-dependently regulate peripheral insulin sensitivity. This introduces a potential novel mechanism for the regulation of peripheral insulin sensitivity and underlines the importance of cerebral insulin action for the whole organism.

Characterization of the origin and body of the normal equine rear suspensory ligament using ultrasonography, magnetic resonance imaging, and histology

The suspensory ligament is difficult to image accurately, partly because it contains ligamentous fibers, as well as noncollagenous adipose and muscle tissue in the normal horse. Our hypothesis was that magnetic resonance (MR) imaging would be more accurate than ultrasonography in identifying the size of the suspensory ligament and the presence and size of noncollagenous tissues within the ligament. Eleven horses were used for ultrasonographic and MR imaging and histologic evaluation of the rear suspensory ligament. The origin and body of the normal suspensory ligament had a heterogenous appearance on MR images with two separate islands of mixed signal intensity evident throughout its otherwise hypointense cross-sectional area. Histologically, there were isolated islands of muscle, adipose, loose connective tissue and dense collagenous partitions, organized in two separate bundles that extended through the full length of the suspensory ligament origin and body to the level of its bifurcation. Comparison of MR images with corresponding histologic sections confirmed that islands of heterogenous signal intensity in normal suspensory ligaments correlated well with these bundles. Using ultrasonography, it was impossible to distinguish these islands from surrounding dense collagenous tissue consistently. MR imaging determined the cross-sectional area of the suspensory ligament more accurately than ultrasonography. Based upon these results, MR imaging is superior to ultrasonography for assessment of the suspensory ligament. The appearance associated with normal ligament anatomy needs to be understood before MR signal variation can be considered as indicative of disease in the suspensory ligament.

Establishment and characterization of a canine soft tissue sarcoma cell line

Stringently controlled in vitro experiments are a necessary part of translational research. Cell lines are useful for exploring the underlying biology of cancer. Very few canine soft tissue sarcoma cell lines exist. This report describes the establishment of a new canine soft tissue sarcoma cell line (MBSa1) derived from a high-grade, metastatic neurofibrosarcoma. The primary tumor tissue was obtained from a 12-year-old neutered male German Shepherd Dog and was maintained in tissue culture for a minimum of 20 passages over 7 months. MBSa1 was injected into athymic mice to determine tumorigenicity. Five million cells were injected into the subcutis of the right flank of athymic nude mice. Nine of the 10 mice grew tumors 1 cm or larger within 8 weeks of cell injection. The large number of in vitro passages coupled with solid tumor formation in athymic nude mice demonstrates that MBSa1 has been immortalized and is tumorigenic.

Adipose tissue pathways involved in weight loss of cancer cachexia

Background:

The regulatory gene pathways that accompany loss of adipose tissue in cancer cachexia are unknown and were explored using pangenomic transcriptome profiling.

Methods:

Global gene expression profiles of abdominal subcutaneous adipose tissue were studied in gastrointestinal cancer patients with (n=13) or without (n=14) cachexia.

Results:

Cachexia was accompanied by preferential loss of adipose tissue and decreased fat cell volume, but not number. Adipose tissue pathways regulating energy turnover were upregulated, whereas genes in pathways related to cell and tissue structure (cellular adhesion, extracellular matrix and actin cytoskeleton) were downregulated in cachectic patients. Transcriptional response elements for hepatic nuclear factor-4 (HNF4) were overrepresented in the promoters of extracellular matrix and adhesion molecule genes, and adipose HNF4 mRNA was downregulated in cachexia.

Conclusions:

Cancer cachexia is characterised by preferential loss of adipose tissue; muscle mass is less affected. Loss of adipose tissue is secondary to a decrease in adipocyte lipid content and associates with changes in the expression of genes that regulate energy turnover, cytoskeleton and extracellular matrix, which suggest high tissue remodelling. Changes in gene expression in cachexia are reciprocal to those observed in obesity, suggesting that regulation of fat mass at least partly corresponds to two sides of the same coin.

C/EBPalpha and C/EBPbeta are required for Sebocyte differentiation and stratified squamous differentiation in adult mouse skin

C/EBPalpha and C/EBPbeta are bZIP transcription factors that are highly expressed in the interfollicular epidermis and sebaceous glands of skin and yet germ line deletion of either family member alone has only mild or no effect on keratinocyte biology and their role in sebocyte biology has never been examined. To address possible functional redundancies and reveal functional roles of C/EBPalpha and C/EBPbeta in postnatal skin, mouse models were developed in which either family member could be acutely ablated alone or together in the epidermis and sebaceous glands of adult mice. Acute removal of either C/EBPalpha or C/EBPbeta alone in adult mouse skin revealed modest to no discernable changes in epidermis or sebaceous glands. In contrast, co-ablation of C/EBPalpha and C/EBPbeta in postnatal epidermis resulted in disruption of stratified squamous differentiation characterized by hyperproliferation of basal and suprabasal keratinocytes and a defective basal to spinous keratinocyte transition involving an expanded basal compartment and a diminished and delayed spinous compartment. Acute co-ablation of C/EBPalpha and C/EBPbeta in sebaceous glands resulted in severe morphological defects, and sebocyte differentiation was blocked as determined by lack of sebum production and reduced expression of stearoyl-CoA desaturase (SCD3) and melanocortin 5 receptor (MC5R), two markers of terminal sebocyte differentiation. Specialized sebocytes of Meibomian glands and preputial glands were also affected. Our results indicate that in adult mouse skin, C/EBPalpha and C/EBPbeta are critically involved in regulating sebocyte differentiation and epidermal homeostasis involving the basal to spinous keratinocyte transition and basal cell cycle withdrawal.

Reluctant to dive: coelomic effusion in a frog

An adult female, albino South African Clawed frog (Xenopus laevis) from a research colony at the Biological Resources Facility of the College of Agriculture and Life Sciences at North Carolina State University (NCSU) was presented with depression, lethargy, loss of diving reflex, and a distended abdomen. Cytologic examination of coelomic effusion fluid at the NCSU veterinary teaching hospital revealed a mixed population of inflammatory cells, including heterophils and a predominance of large mononuclear cells (macrophages) that often contained intracytoplasmic, negatively-stained, rod-shaped to filamentous organisms consistent with Mycobacterium sp. Ziehl-Neelsen stain revealed bright pink to red, acid-fast organisms with a beaded appearance. Histopathologic findings in tissues obtained at necropsy included marked, multifocal to coalescing, heterophilic, granulomatous and fibrinous coelomitis as well as severe multifocal heterophilic and granulomatous hepatitis, interstitial pneumonia and sinusitis/rhinitis. Slender gram-positive, acid-fast bacterial rods were identified in sections of coelomic pleura, kidneys, nasal cavities, spleen, liver, and pulmonary interstitium, indicative of systemic mycobacteriosis. Based on mycobacterial culture, the organism was identified as M marinum complex. Mycobacteria are variably gram-positive, often acid-fast, small rods that are ubiquitous in aquatic environments. The clinical and pathologic spectrum of disease in amphibians depends on host and pathogen status. Xenopus sp and several other frogs are good models for studying the pathogenesis of M tuberculosis infection. In addition to culture, polymerase chain reaction assays may be used for definitive identification of the organisms; accurate speciation may require further genetic investigation.

Animal models for skin blistering conditions: absence of laminin 5 causes hereditary junctional mechanobullous disease in the Belgian horse

Recent achievements in the genetic correction of keratinocytes isolated from patients with junctional epidermolysis bullosa have paved the way to a gene therapy approach for the disease. Because gene therapy protocols require preclinical validation in animals, we have characterized spontaneous animal models of junctional epidermolysis bullosa. In this study we have elucidated the genetic basis of the hereditary junctional mechanobullous disease in the Belgian horse, a condition characterized by blistering of the skin and mouth epithelia, and exungulation (loss of the hoof). Immunofluorescence analysis associated the condition to the absent expression of the gamma2 chain of laminin 5 and designated Lamc2 as the candidate gene. Comparative analysis of the nucleotide sequence of the full-length gamma2 cDNA isolated by reverse transcription polymerase chain reaction amplification of total RNA purified from the epithelium of a junctional epidermolysis bullosa foal and a healthy control disclosed a homozygous basepair insertion (1368insC) in the affected animal. Mutation 1368insC results in a downstream premature termination codon and is predicted to cause absent expression of the laminin gamma2 polypeptide. Our results also show that: (i) the horse junctional epidermolysis bullosa genetically corresponds to the severe Herlitz form of junctional epidermolysis bullosa in man; (ii) the amino acid sequence and structure of the horse laminin gamma2 chain are virtually identical to the human counterpart; (iii) the moderate eruption of skin blisters in the affected animals with respect to the human Herlitz junctional epidermolysis bullosa patients correlates with the protection provided by hair. Our observations suggest that the affected foals are a convenient source of epithelial cells from tissues that cannot be obtained from human junctional epidermolysis bullosa patients, and imply that hairless strains of animals with recessive skin disorders would be the best models for in vivo gene therapy approaches to skin blistering diseases.

Bcl-2 and Bax interactions in mitochondria probed with green fluorescent protein and fluorescence resonance energy transfer

It has been hypothesized that interaction of Bcl-2 and Bax may regulate apoptosis. The spatial and temporal interaction of Bcl-2 and Bax at the single cell level has not, however, been demonstrated. To achieve this goal, we have developed two-fusion FRET (fluorescence resonance energy transfer). Using green fluorescent protein (GFP)-Bax and blue fluorescent protein (BFP)-Bcl-2 fusion proteins coexpressed in the same cell, we demonstrate a direct interaction between Bcl-2 and Bax in individual mitochondria. Mitochondrially localized cytochrome c-GFP and BFP-Bcl-2 showed little or no FRET, while nuclear-localized GFP-human papillomavirus E6 and BFP-Bcl-2 did not interact when coexpressed in the same cell. These findings indicate that two-fusion FRET provides an opportunity to examine the interaction between two different proteins coexpressed in single intact mammalian cells.

Development of a stable single-vial formulation for a new technetium complex using bilayer lyophilization

The interaction between different components used in the preparation of a new radiodiagnostic agent, BMS-181321, was overcome by its lyophilization as a bilayered product. BMS-181321 is composed of a nitroimidazole ligand BMS-181032, that is complexed with technetium-99m just before it is used in radionuclide imaging studies. Stannous chloride is required to reduce technetium from the +7 to the +5 oxidation state before it can be complexed by the ligand. Because BMS-181032 is unstable in the presence of stannous chloride (when mixed in the liquid or solid state), the two components must be contained in separate vials. A bilayered lyophile was manufactured, containing the ligand and stannous chloride in separate layers in a single vial. The bilayered product was manufactured by first filling a solution of the ligand into a vial and freezing the solution. A solution containing stannous chloride was then filled into the same vial on top of the frozen layer of ligand, and this second layer was also frozen. The two frozen layers were then lyophilized to a dry solid cake. The resulting bilayered product showed stability comparable to that seen when the ligand and the reducing agent were contained in separate vials. The separation provided by the layering was sufficient to prevent any significant interaction between the reducing agent and the ligand.

Anatomy of the distal interphalangeal joint of the mature horse: relationships with navicular suspensory ligaments, sensory nerves and neurovascular bundle

The anatomy of the distal interphalangeal (DIP) joint in the adult horse is described in relationship to the suspensory ligaments of the navicular bone, the neurovascular bundle and the sensory nerves to these periarticular regions. Using polymer plastic injections, the synovial cavity of the DIP joint was observed to have a complex relationship to the proximal suspensory or collateral sesamoidean ligament (CSL) of the navicular bone with the cavity forming cranial and caudal compartments around the CSL abaxially. Sensory nerves, as identified by peptide immunocytochemistry and silver/gold chloride axonal impregnation, were present superficially throughout the dorsal and palmar parts of the CSL, the distal sesamoidean impar ligament and in the periarticular connective tissues. These anatomical observations provide support for the idea that a DIP joint injection of local anaesthetic cannot be considered to be selective for only the joint surfaces, but must be considered also to desensitise much of the navicular suspensory apparatus, navicular bone and proximal intramedullary portions of the distal phalanx. However, while a DIP joint injection is not selective for only the joint surfaces, we believe that it is useful in terms of the diagnosis of painful sensations arising from parts of the navicular bone, the suspensory apparatus and proximal positions of the distal phalanx. These anatomical findings are discussed in terms of the potential effects of local anaesthesia injected into the DIP joint with known clinical and necropsy observations of Dyson and Kidd (1993).