Evidence Of Vacuolation Research Articles

BG07 VEXAS syndrome without the V: a New Zealand case report

Abstract VEXAS syndrome (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) is an autoinflammatory condition first described in 2020, often with cutaneous features. Effective treatments are yet to be established. We describe the case of a 60-year-old man who presented with rapidly enlarging cutaneous lesions to the face and neck, polychondritis, myalgia, arthralgia and fevers over a 2-month period. Skin biopsy showed a neutrophilic dermatosis with a differential diagnosis of seronegative rheumatoid neutrophilic dermatosis and atypical Sweet syndrome. His cutaneous complaints improved following treatment with prednisone 30 mg. His cutaneous symptoms relapsed on attempts to wean prednisone to < 20 mg. He then developed macrocytic anaemia and transient thrombocytopenia. He was then hospitalized and treated for community-acquired pneumonia. Bone marrow biopsy was normal and without evidence of vacuoles. The patient developed progressive fatigue and shortness of breath, with transient stenosing tenosynovitis and Raynaud symptoms over 3 years. He was most burdened by soft tissue and joint swelling, with muscular stiffness and pain particularly affecting his hands and feet. Methotrexate was partially effective in managing myalgia. Dapsone, hydroxy­chloroquine, mycophenolate, cyclophosphamide and colchicine were tried without benefit. Following a regional dermatology multidisciplinary team meeting, the patient was screened for VEXAS syndrome. Blood and bone marrow genetic testing found a UBA1 mutation load which is 50% of total DNA, confirming a diagnosis of VEXAS syndrome and the highest found in a New Zealand laboratory to date. Bone marrow images were re-examined, with no vacuolization noted. Our patient had a heterozygous UBA1C (Met41Leu) variant present in 50% of his blood and bone marrow DNA—to our knowledge the highest VEXAS genetic mutation seen in a New Zealand laboratory so far. Our case illustrates that, in patients with clinical evidence of VEXAS syndrome, the absence of vacuolization on bone marrow biopsy should not be a criterion for exclusion.

Western diet (WD) activates pancreatic Toll‐like receptor 4 (TLR4) signaling in female rats: a potential mechanism of WD‐induced insulin resistance

BackgroundOverconsumption of a WD, a high‐fat and high‐sugar diet, has plagued the United States contributing to the widespread prevalence of type 2 diabetes (T2DM). Insulin resistance (IR) plays a key role in the development of T2DM and is a consistent finding among T2DM patients. The pathogenesis of IR, however, is not well understood. Based on recent evidence that inflammation precedes IR, and previous findings from our lab showing involvement of Toll‐like receptor 4 (TLR4) signaling in diabetic vascular inflammation, we hypothesize that WD leads to pancreatic inflammation through TLR4 signaling activation, contributing to IR.MethodsOur lab has established a model of a WD‐induced metabolic syndrome and IR in female rats. Eight‐week old female Wistar rats were randomized into two experimental groups: Control (n = 9) and WD group (n = 16). The control group received a regular chow diet (5% fat, 48.7% carbohydrates [3.2% sucrose], and 24.1% protein), while the WD group received a WD (40% fat, 43% carbohydrates [34% sucrose], 17% protein), for 28 weeks. Body weight and food consumption were measured weekly. Lipid and glucose metabolism, and intraperitoneal glucose tolerance tests (IPGTT) were measured. Quantitative IR was assessed using Homeostasis Model Assessment of Insulin Resistance (HOMA‐IR), while functional beta cell capacity was assessed via HOMA‐B calculation. At the terminal experiments, pancreas’ were isolated for molecular (TLR4 signaling) and histological (hematoxylin and eosin, H&E) analysis.ResultsWD group exhibited greater body weight (415.1 ± 30.9 vs. 323.0 ± 24.0 g controls, p<0.01), and increased daily caloric consumption (130.5 ± 7.36 vs.110.7 ± 7.0 kcals controls, p<0.05) in spite of a significant reduction in daily food intake (23.7 ± 1.5 vs. 31.5 ± 1.8 g controls, p<0.01). WD negatively interfered in the glucose metabolism as evidenced by increased blood glucose area under the curve during IPGTT (17531.8 ± 574.3 vs. 12381.25 ± 1480.6 a.u. controls, p<0.001). IR in the WD group was confirmed by increased HOMA‐IR (8.09 ± 1.90 vs. 2.05 ± .042 a.u. controls, p<0.001), which was accompanied by hyperinsulinemia (0.93 ± 0.1 vs. 0.30 ± 0.09 mg/dL controls, p<0.01). No changes were observed in the HOMA‐B, suggesting that β cells remain functional. Moreover, no evidence of vacuolation, irregular outlining and size of the Langerhans islets, which are all markers of β cell dysfunction, were observed in the H&E stained pancreatic section from the WD group. Pancreatic inflammation in the WD group was confirmed by a 42% increase in TNF‐α expression (p<0.05), an inflammatory marker. Strikingly, pancreatic TLR4 (1.8‐fold increased, p<0.05) and its downstream molecule TNF‐receptor associated factor 6 (TRAF6) (3.1‐fold increased, p<0.001) were markedly upregulated in the WD group in comparison to controls, indicating TLR4/TRAF6 signaling activation in the pancreas.ConclusionOur findings suggest that a WD can induce IR along with activation of pancreatic TLR4 signaling‐related inflammation. These results can provide new insights into how high fat and fat sugar diet choices can causes inflammation in the pancreas.Support or Funding InformationNIH

Cytologic, histologic, and immunohistochemical features of lingual liposarcoma in a dog

A 9-year-old female spayed mixed-breed dog was presented to the referring veterinarian with a history of decreased appetite and difficulty with prehension and swallowing because of a firm oval mass in the tongue. On cytologic evaluation of a fine-needle aspirate of the mass there were numerous round to polygonal cells organized individually or in loose clusters with rare branching capillaries. The cells had eosinophilic granular cytoplasm, round to oval nuclei, and occasionally indistinct borders. The cytologic diagnosis was granular cell tumor (GCT) of the tongue. Impression smears of a biopsy sample of the lingual mass contained similar eosinophilic granular cells with variable numbers of clear vacuoles in the background, numerous perivascular arrangements, and occasional lipoblasts, suggestive of liposarcoma. On histologic examination the tumor was composed of numerous lipocytes with rare foci of round eosinophilic granular cells without evidence of vacuolation; occasionally, atypical mitotic figures were seen. Immunohistochemically, the cells were uniformly negative for periodic acid-Schiff and did not express smooth muscle actin, desmin, or cytokeratin but were immunoreactive for vimentin and S100. A diagnosis of well-differentiated liposarcoma was made on the basis of morphologic and immunohistochemical results. Eosinophilic granular cells may be a component of well-differentiated liposarcoma and are not limited to GCT. Liposarcoma should be considered in the differential diagnoses of lingual tumors in the dog when cytological evaluation reveals eosinophilic granular cells consistent with GCT.

Cytoplasmic changes in primary cultured adult mouse sensory neurons induced by ethanol and acetaldehyde treatments

Primary cultured sensory neurons prepared from adult mice were maintained for 8 days in vitro. Such cultures were exposed to either a range of ethanol concentrations (50-300 mM) or acetaldehyde (0.5-2 mM) in serum-free medium for up to 24 h. Treated neuronal cultures, together with untreated controls in both the presence and absence of serum, were prepared for transmission electron microscopy. Nuclear morphology was not changed following treatment with either substance at the doses studied. A number of changes were observed, however, in the cytoplasm of neurons, and these were intensified by an increase in concentration and the length of exposure. Acetaldehyde induced effects at a much lower concentration than was required to induce a response with ethanol. Myelin lamellae loosely wound around dense granular core material appeared in multivesicular bodies at low doses. The prevalence of these increased with concentrations of 100 mM ethanol and 1 mM acetaldehyde; the numbers of lamellae in each myelin figure also increased but the core material was less prominent. Electron-dense bodies were also evident at higher dosages together with evidence of vacuolation of the endoplasmic reticulum and Golgi complexes. Mitochondrial profiles similar to those in untreated neurons persisted throughout the exposure periods. The generation of these inclusions may reflect a mechanism of membrane turnover, both of internal systems and cell membrane cycling, as a response to alcohol and aldehyde treatment.

Influence of stereotaxically injected scrapie on neurotransmitter systems of mouse cerebellum

The 22L strain of scrapie was injected stereotaxically into the cerebellum of C57BL/6J mice to determine its effect on several cerebellar neurotransmitter systems during the early clinical stages of the disease. In this model vacuolar lesions are restricted to the cerebellum with no evidence of vacuolization in other brain regions. Although lesions develop throughtout all cell layers of the cerebellum, they are most severe in the granule cell layer. Modest but significant (P < 0.01) reductions in cerebellar weight, glutamate decarboxylase activity, and in the affinity of the N 6-[adenine-2,8- 3H]cyclohexyladenosine binding sites, were observed in scrapie affected mice. The densities of the high- and low-affinity adenosine receptors were unaffected. Adenosine receptors in the cerebellum are highly localized to the axon terminals of the glutamatergic, GABA receptive granule cells. GABA, benzodiazepine, glutamate, and muscarinic cholinergic receptors were significantly altered. In addition, the high-affinity uptake of glutamate, and the activity of choline acetyltransferase were not significantly changed. GABA high-affinity uptake was slightly increased. Even though the granule cell layer of the cerebellum had undergone severe vacuolation, only modest neurotransmitter changes were apparent. Although these results suggest a tenous relationship between scrapie pathology and the integrity of neurotransmitter systems, it is possible that compensatory neurochemical changes in uncompromised neuronal populations may have masked potentially specific neurotransmitter effects.