Cell-specific expression of functional glucose transporter 8 in mammary gland.

Differentiated mammary epithelial cells are responsible for milk synthesis during lactation, supporting early postnatal life in mammals. These cells are found in the terminal alveoli of a secretory epithelium, which is surrounded by myoepithelial cells and a stroma rich in fatty tissue. The aim of this study was to explore the cell-specific expression of the glucose transporter GLUT8 in mammary gland and evaluate its functionality for glucose transport, in order to confirm its role in lactose synthesis. Our histological results revealed that GLUT8 is expressed in adipocytes and the epithelial and myoepithelial cells in mammary gland, with a predominant intracellular granular pattern. Colocalization studies of endogenous and green fluorescent protein fused GLUT8 revealed their expressions in lysosome and Golgi, respectively, with Pearson's coefficient correlations of 0.82 ± 0.05 and 0.68 ± 0.16. Functional studies of dileucine to dialanine mutant of GLUT8 showed a fructose-sensitive 2-deoxy glucose uptake at a rate of 83.3 pmoles/(min∗106 cells), 7 folds over empty vector, with a 60 ± 4 and 72 ± 6% decline in 2-deoxy glucose in the presence of 20 and 50 mM fructose, respectively. We concluded that functional GLUT8 is expressed in mammary gland, localizing in mammary epithelial and myoepithelial cells, and adipocytes. In lactation, GLUT8 is expressed mainly in luminal epithelial cells, at the compartments of the endomembrane system. It is necessary to explore the physiological/pathological functions of GLUT8 in mammary gland, including its role in lactation.

Urate transport capacity of glucose transporter 9 and urate transporter 1 in cartilage chondrocytes.

Chronic gouty arthritis, caused by a persistent increase in, and the deposition of, soluble uric acid (sUA), can induce pathological chondrocyte destruction; however, the effects of urate transport and intracellular sUA on chondrocyte functionality and viability are yet to be fully determined. Thus, the aim of the present study was to investigate the presence and functionality of a urate transport system in chondrocytes. The expression profiles of two primary urate reabsorptive transporters, glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1), in human articular cartilage and chondrocyte cell lines were examined via western blotting, reverse transcription­quantitative PCR, immunohistochemistry and immunofluorescence. Then, chondrocytes were incubated with exogenous sUA at increasing concentrations. Negative control assays were conducted via the specific knockdown of GLUT9 and URAT1 with lentiviral short hairpin (sh)RNAs, and by pretreatment with benzbromarone, a known inhibitor of the two transporters. Intracellular UA concentrations were measured using colorimetric assays. The expression levels of GLUT9 and URAT1 were determined in cartilage tissues and chondrocyte cell lines. Incubation of chondrocytes with sUA led to a concentration­dependent increase in intracellular urate concentrations, which was inhibited by GLUT9 or URAT1 knockdown, or by benzbromarone pretreatment (27.13±2.70, 44.22±2.34 and 58.46±2.32% reduction, respectively). In particular, benzbromarone further decreased the already­reduced intracellular UA concentrations in HC­shGLUT9 and HC­shURAT1 cells by 46.79±2.46 and 39.79±2.22%, respectively. Cells overexpressing GLUT9 and URAT1 were used as the positive cell control, which showed increased intracellular UA concentrations that could be reversed by treatment with benzbromarone. In conclusion, chondrocytes may possess an active UA transport system. GLUT9 and URAT1 functioned synergistically to transport UA into the chondrocyte cytoplasm, which was inhibited by specific gene knockdowns and drug­induced inhibition. These results may be fundamental in the further investigation of the pathological changes to chondrocytes induced by sUA during gouty arthritis, and identified UA transport processes as potential targets for the early control of chronic gouty arthritis.

Localization of Glucose Transporter 10 to Hair Cells' Cuticular Plate in the Mouse Inner Ear.

This study aimed to investigate the localization pattern of glucose transporters (Gluts) in mouse cochlea. Genome-wide gene expression analysis using CodeLink™ bioarrays indicated that Glut1 and Glut10 were highly expressed (~10-fold) in mouse cochlea compared with the other members of glucose transporters (Glut2-6, Glut8, and Glut9). Semiquantitative RT-PCR and western blotting confirmed that Glut10 expression in mouse cochlea was high throughout the embryogenesis and postnatal development. Immunofluorescent staining showed that Glut10 protein was localized in the cuticular plate of the outer and inner cochlear hair cells and in the ampullary crest of the vestibular system. Based on these results, it was supposed that Glut10 may contribute to glucose transport from the endolymph to the hair cells across the cuticular plate.

Glucose transporter expression in the human colon.

AIM: To investigate by immunostaining glucose transporter expression in human colorectal mucosa in controls and patients with inflammatory bowel disease (IBD). METHODS: Colorectal samples were obtained from patients undergoing lower endoscopic colonoscopy or recto-sigmoidoscopy. Patients diagnosed with ulcerative colitis (n = 18) or Crohn's disease (n = 10) and scheduled for diagnostic colonoscopy were enrolled. Patients who underwent colonoscopy for prevention screening of colorectal cancer or were followed-up after polypectomy or had a history of lower gastrointestinal symptoms were designated as the control group (CTRL, n = 16). Inflammatory status of the mucosa at the sampling site was evaluated histologically and/or endoscopically. A total of 147 biopsies of colorectal mucosa were collected and processed for immunohistochemistry analysis. The expression of GLUT2, SGLT1, and GLUT5 glucose transporters was investigated using immunoperoxidase labeling. To compare immunoreactivity of GLUT5 and LYVE-1, which is a marker for lymphatic vessel endothelium, double-labeled confocal microscopy was used. RESULTS: Immunohistochemical analysis revealed that GLUT2, SGLT1, and GLUT5 were expressed only in short epithelial portions of the large intestinal mucosa. No important differences were observed in glucose transporter expression between the samples obtained from the different portions of the colorectal tract and between the different patient groups. Unexpectedly, GLUT5 expression was also identified in vessels, mainly concentrated in specific areas where the vessels were clustered. Immunostaining with LYVE-1 and GLUT5 antibodies revealed that GLUT5-immunoreactive (-IR) clusters of vessels were concentrated in areas internal to those that were LYVE-1 positive. GLUT5 and LYVE-1 did not appear to be colocalized but rather showed a close topographical relationship on the endothelium. Based on their LYVE-1 expression, GLUT5-IR vessels were identified as lymphatic. Both inflamed and non-inflamed mucosal colorectal tissue biopsies from the IBD and CTRL patients showed GLUT5-IR clusters of lymphatic vessels. CONCLUSION: Glucose transporter immunoreactivity is present in colorectal mucosa in controls and IBD patients. GLUT5 expression is also associated with lymphatic vessels. This novel finding aids in the characterization of lymphatic vasculature in IBD patients.

Quantitative Analysis of Glucose Metabolic Cleavage in Glucose Transporters Overexpressed Cancer Cells by Target-Specific Fluorescent Gold Nanoclusters.

The glucose metabolism rate in cancer cells is a crucial piece of information for the cancer aggressiveness. A feasible method to monitor processes of oncogenic mutations has been demonstrated in this work. The fluorescent gold nanoclusters conjugated with glucose (glucose-AuNCs) were successfully synthesized as a cancer-targeting probe for glucose transporters (Gluts) overexpressed by U-87 MG cancer cells, which can be observed under confocal microscopy. The structural and optical characterizations of fluorescent glucose-AuNCs were confirmed by transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR). The MTT assay exhibited the high biocompatibility of water-soluble glucose-AuNCs for further biomedical applications. The glucose metabolic cleavage of glucose-AuNCs by glycolytic enzymes from U-87 MG cancer cell was measured by fluorescence change of glucose-AuNCs. The fluorescence change based on the integrated area under fluorescence spectra ( A t) of glucose-AuNCs was plotted as a function of different reaction time ( t) with glycolytic enzymes. The fitted curve of A t versus t showed the first-order kinetics to explain the mechanism of glucose metabolic cleavage rate of glucose-AuNCs by glycolytic enzymes. The rate constant k could be utilized to determine the glucose metabolism rate of glucose-AuNCs for the quantitative analysis of cancer aggressiveness. Our work provides a practical application of target-specific glucose-AuNCs as a fluorescence probe to analyze the glucose metabolism in Gluts overexpressed cancer cells.

Masa torácica congénita: hemangioma capilar pulmonar, un diagnóstico inusual / Congenital lung mass: Pulmonary hemangioma, an unusual diagnosis

Introducción: Las masas pulmonares congénitas (MPC) presentan una incidencia de 27-33/100.000 habitantes. El diagnóstico varía en función de la sintomatología, la localización y la magnitud de la lesión. La causa más frecuente de MPC son las alteraciones del desa-rrollo de la vía respiratoria, pero en las que no cumplan las características radiológicas debe considerarse el hemangioma pulmonar. Caso clínico: Neonato con hemangioma capilar pulmonar congénito. Se revisan los casos de hemangiomas pulmonares en menores de 1 año publicados en la literatura hasta 2015. Resultados: Se identificaron 6 casos. La sintomatología más frecuente fue la dificultad respiratoria. En todos los casos se realizó una tomografía computarizada pulmonar, que mostraba una masa isodensa en 5 de los 6 casos. Un caso fue estudiado mediante resonancia magnética (RM) con isoseñal al músculo en T1, e hiperintensa en T2. Se procedió a una exéresis quirúrgica en 5 de los 6 casos, el restante recibió tratamiento con propranolol con buen resultado. Conclusiones: Los hemangiomas intratorácicos son inusuales y suelen presentarse como una masa sólida única isodensa en la radiografía. En la ecografía se observan como áreas heterogéneas con vasos visibles y calcificaciones. Consideramos la RM con gadolinio la prueba estándar de referencia para el estudio de las MPC. Los hemangiomas congénitos (HC) se presentan en la RM como masas bien delimitadas hiperintensas en T2, isointensas en T1 y con realce tras gadolinio. La evolución de los HC es impredecible y pueden presentar una resolución completa. El tratamiento debe estar supeditado a la clínica del paciente, y podría considerarse añadir propranolol a las opciones quirúrgicas, aunque es necesaria la comunicación de nuevos casos para valorar su eficacia. Si se procede a la exéresis, el estudio histopatológico con positividad para marcadores CD31 y CD34 y negatividad para GLUT-1 confirmará el diagnóstico (AU)

Introduction: Congenital pulmonary masses (CPM) have an incidence of 27-33/100,000. Timing of diagnosis depends on the sym-ptoms, location and size of the lesion. The most commonly cause are developmental abnormalities of the pulmonary airways and vasculature, but pulmonary hemangioma can occur as a single asymptomatic solid mass. Case report: A case of MPC is presented with a final diagnosis of congenital pulmonary capillary hemangioma. Pulmonary heman-giomas in infants published in English literature until 2015 are reviewed and analyzed. Results: 6 cases were identified. The most common symptoms were respiratory distress. Study was conducted with lung CT in all cases showing a mass isodense. 1 case was studied by MRI; it showed hyperintensity in T2 sequences and isointense to muscle on T1. Surgical resection was the treatment in 5 of the 6 cases; one was treated with propranolol being successful. Conclusions: Intrathoracic hemagiomas are unusual, and usually present as a single solid isodense mass on radiography. In ul-trasound they are heterogeneous with visible vessels and calcifications. We consider gadolinium MRI gold standard for the study of CPM. Congenital hemagiomas in MRI show hyperintensity on T2 sequences and gadolinium enhancement. They can resolve sponta-neously, therefore the management should be subject to the patient's clinical and propranolol should be considered in addition to surgical options. If excision is necessary histopathologic findings with positivity for endothelial markers such as CD31, CD34 and nega-tivity for GLUT-1, will confirm our diagnosis (AU)

Immunoreactivity of urate transporters, GLUT9 and URAT1, is located in epithelial cells of the choroid plexus of human brains.

It has been suggested that urate plays a protective role in neurons, while hyperuricemia is correlated with atherosclerosis and cardiovascular disease. However, whether there is a system that directly transports urate into the brain remains to be clarified. In this study, the localization of glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1), which are known to be representative reabsorptive urate transporters, was immunohistochemically examined in autopsied human brains. Immunoreactivity of GLUT9 was observed on the apical side of the cytoplasm of epithelial cells in the choroid plexus and in the cilia of ependymal cells of the human brain. Immunoreactivity of URAT1 was observed on the basolateral side of the cytoplasm of epithelial cells in the choroid plexus. In addition, immunoreactivity of GLUT9 and URAT1 was not observed in microvessels of the human brains. The choroid plexus and renal proximal tubule were similar in having a polarized distribution of these two transporters with the two transporters on opposite membranes, but the two transporters' distribution differs between the choroid plexus and the kidney in terms of which membrane (apical/basal) expresses which transporter. These findings support the hypothesis of the direct transport of intravascular urate into the central nervous system through the choroid plexus.

Tumor híbrido de la vaina del nervio periférico de localización digital con componente neurofibroma-perineuroma. Descripción de un caso y revisión de la literatura / Digital hybrid peripheral nerve sheath tumour with neurofibroma-perineurioma components: a case report and review of the literature

El tumor híbrido de vaina de nervio periférico es una neoplasia mesenquimal benigna de la que se han publicado pocos casos, que ha sido incluida recientemente en la clasificación de la OMS de partes blandas, y que muestra una amplia distribución, afectando predominantemente a extremidades y tronco. Los hallazgos histológicos revelan la presencia de 2 o más componentes celulares diferentes originados en la vaina del nervio periférico con una proporción variable de neurofibroma, schwannoma y perineuroma. Describimos el caso de un paciente varón de 65 años de edad con un nódulo no doloroso en el quinto dedo de mano izquierda, que presenta componentes de neurofibroma y perineuroma. Describimos los hallazgos histológicos e inmunohistoquímicos reportados en la literatura más reciente acerca de este tumor peculiar y poco reconocido (AU)

Hybrid peripheral nerve sheath tumour is a rare mesenchymal benign neoplasm recently included in the WHO classification of soft tissue tumours. It has a wide distribution but predominantly affects limbs and trunk. Histological findings reveal the presence of 2 or more cellular components originating in the peripheral nerve sheath with variable proportions of neurofibroma, schwannoma and perineurioma. We report a case of a 65-year-old male with a painless nodule in the 5th finger of his left hand which showed microscopic features of neurofibroma and perineurioma. We review the histological and immunohistochemical findings of this unusual, and often over-looked, tumour in the recent literature (AU)

Immunoreactivity of glucose transporter 8 is localized in the epithelial cells of the choroid plexus and in ependymal cells.

High fructose intake is known to be associated with increased plasma triglyceride concentration, impaired glucose tolerance, insulin resistance, and high blood pressure. In addition, excess fructose intake is also thought to be a risk factor for dementia. Previous immunohistochemical studies have shown the presence of glucose transporter 5 (GLUT5), a major transporter of fructose, in the epithelial cells of the choroid plexus and ependymal cells in the brains of humans, rats, and mice, while GLUT2, a minor transporter of fructose, was localized in the ependymal cells of rat brain. In this study, immunoreactivity for the fructose transporter GLUT8 was observed in the cytoplasm of the epithelial cells in the choroid plexus and in the ependymal cells of the brains of humans and mice. These structures were not immunoreactive for GLUT7, GLUT11, and GLUT12. Our findings support the hypothesis of the transport of intravascular fructose through the epithelial cells of the choroid plexus and the ependymal cells.

Insulin-positive, Glut2-low cells present within mouse pancreas exhibit lineage plasticity and are enriched within extra-islet endocrine cell clusters.

Regeneration of insulin-producing ß-cells from resident pancreas progenitors requires an understanding of both progenitor identity and lineage plasticity. One model suggested that a rare ß-cell sub-population within islets demonstrated multi-lineage plasticity. We hypothesized that ß-cells from young mice (postnatal day 7, P7) exhibit such plasticity and used a model of islet dedifferentiation toward a ductal epithelial-cell phenotype to test this theory. RIPCre;Z/AP(+/+) mice were used to lineage trace the fate of ß-cells during dedifferentiation culture by a human placental alkaline phosphatase (HPAP) reporter. There was a significant loss of HPAP-expressing ß-cells in culture, but remaining HPAP(+) cells lost insulin expression while gaining expression of the epithelial duct cell marker cytokeratin-19 (Ck19). Flow cytometry and recovery of ß-cell subpopulations from whole pancreas vs. islets suggest that the HPAP(+)Ck19(+) cells had derived from insulin-positive, glucose-transporter-2-low (Ins(+)Glut2(LO)) cells, representing 3.5% of all insulin-expressing cells. The majority of these cells were found outside of islets within clusters of <5 ß-cells. These insulin(+)Glut2(LO) cells demonstrated a greater proliferation rate in vivo and in vitro as compared to insulin(+)Glut2(+) cells at P7, were retained into adulthood, and a subset differentiated into endocrine, ductal, and neural lineages, illustrating substantial plasticity. Results were confirmed using RIPCre;ROSA- eYFP mice. Quantitative PCR data indicated these cells possess an immature ß-cell phenotype. These Ins(+)Glut2(LO) cells may represent a resident population of cells capable of forming new, functional ß-cells, and which may be potentially exploited for regenerative therapies in the future.

Compound Tufuling Granules ([characters: see text]) regulate glucose transporter 9 expression in kidney to influence serum uric acid level in hyperuricemia mice.

OBJECTIVE: To explore the effect of Compound Tufuling Granules ([characters: see text], CTG) on regulating glucose transporter 9 (GLUT9) expression in the kidney to influence the uric acid excretion by the kidney and serum uric acid (SUA) level in hyperuricemia mice. METHODS: Sixty Kunming male mice were randomly divided into the control group, model group, benzbromarone group, and CTG high-, middle- and low-dose groups. The yeast extract and uricase inhibition method were used to build hyperuricemia model, and the corresponding drugs were administrated on the 7th day. On the 21st day the 24-h urine was collected, on the 22nd day the blood was collected, the SUA level was detected by uricase colorimetry, and the mRNA and protein expressions of GLUT9 were detected by quantitative real-time polymerase chain reaction and Western blot, respectively. RESULTS: Compared with the model group, the levels of SUA and the mRNA and protein expressions of GLUT9 were significantly decreased, and the fraction excretion of uric acid (FEUA) was significantly increased in the CTG groups and benzbromarone group (all P<0.05). There was no significant difference in the above indicators between the CTG high-dose group and benzbromarone group (P>0.05). SUA is positively related to the GLUT9 mRNA and protein expressions in the kidney (P<0.05 or P<0.01). CONCLUSIONS: CTG can significantly reduce the SUA and increase the FEUA. In addition, CTG can effectively inhibit the mRNA and protein expressions of GLUT9 in the kidney of hyperuricemia mice to inhibit the uric acid re-absorption, promote uric acid excretion and reduce SUA.

Stage specific expression of ATP-binding cassette and solute carrier superfamily of transporter genes in mammary gland of riverine buffalo (Bubalus bubalis).

In the present study, expression level of various ATP-binding cassette (ABC) viz., ABCA1, ABCA7, ABCG1, ABCG2, and ABCG5; associated transcription factors viz., SREBF1, LXRα (NR1H3), PPARA, and Solute Carriers (SLC); or Glucose transporters (GLUT) viz., SLC2A1(GLUT1), SLC2A4 (GLUT4), SLC2A8 (GLUT8), and SLC2A12 (GLUT12) superfamily of transporters were compared across physiological stages of buffalo mammary gland. The relative expression of ABCA1, and ABCG1 was significantly (p < 0.05) higher in mammary gland of heifer followed by involution and lactation stages. Similarly, ABCA7 gene expression was highest in heifer mammary gland followed by lactation and involution stages. ABCG2 gene expression was significantly (p < 0.05) high in lactating mammary gland in comparison to involution and heifer stages. On the other hand, ABCG5 gene expression was highest in involuting mammary gland followed by lactation and involution stages. Additionally, the expression of LXRα SREBF1, and PPARA which are known to regulate some of the ABC tranporters were also analyzed. The expression of LXRα gene was high in involuting as compared to lactating mammary gland. In contrast, SREBF1 and PPARA expression was significantly (p < 0.05) high in lactating mammary gland. Among the several SLC transporters studied, SLC2A1, SLC2A4, and SLC2A8 showed significant (p < 0.05) higher expression during lactation stage, whereas SLC2A12 expression was greater during heifer stage suggesting SLC2A1, SLC2A4, and SLC2A8 to be the major transporters associated with glucose uptake in buffalo mammary gland. The expression profile of (lactoferrin) LTF, known to be expressed at high level in mammary gland during involution was also studied. As expected, its expression was significantly (p < 0.05) higher during involution in comparison to lactating mammary gland.in buffaloes as well. The inclusion of LTF as a control gene further provided the confidence in the buffalo mammary gland expression data generated in the present study. This study thus helped to provide information about the distinct expression pattern of various transporters and their regulators in buffalo mammary gland during different physiological states.

Expressão imunoistoquímica de GLUT-1 e marcadores de proliferação e apoptose em anomalias vasculares orais / Immunohistochemical expression of GLUT-1 and markers of proliferation and apoptosis in oral vascular anomalies

As anomalias vasculares constituem um grupo de lesões distintas, mas que podem apresentar características clínicas e histopatológicas semelhantes, que podem levar a equívocos diagnósticos.Este estudo objetivou por meio da histopatologia e da expressão imuno-histoquímica daproteína humana transportadora de glicose (GLUT1), identificar e classificar corretamente as anomalias vasculares orais, além de analisar a imunoexpressão de marcadores de proliferação e apoptose (Ki-67 e Bcl2).Todos os casos diagnosticados como "hemangiomas orais" pertencentes aos arquivos do Serviço de Anatomia Patológica da disciplina de Patologia Oral do Departamento de Odontologia (DOD) da Universidade Federal do Rio Grande do Norte (UFRN) foram revisados, totalizando 77 casos. A análise imuno-histoquímica para GLUT-1 revelou que apenas 26 (33,8%) dos espécimes tratavam-se de hemangiomas da infância (HIs) verdadeiros. Os 51 (66,2%%)espécimes GLUT-1 negativos foram então reclassificados em granulomas piogênicos (GPs) e malformações vasculares (MVs) a partir de suas características histopatológicas, totalizando 26 (33,8%) casos de HIs, 20 (26,0%) de GPs e 31 (40,2) casos de MVs orais. Os casos submetidos à análise do marcador Ki-67 apresentaram medianas diferentes HI (13,85), GP (33,70) e MV (4,55) com diferenças estatisticamente significantes entre elas (p<0,001). Em relação à proteína Bcl-2, os grupos também apresentaram diferentes medianas dos escores estabelecidos HI (1,00), GP (1,50), MVs (0,0), demonstrando diferenças estatisticamente significantes entre elas (p<0,001). Não foi observada correlação estatisticamente significante entre os índices de positividade para o Ki-67 e os escores de imunoexpressão de Bcl-2 em nenhum grupo.Dessa maneira, podemos concluir que se faz necessário uma revisão criteriosa e parametrizada dos casos de anomalias vasculares utilizando ferramentas auxiliares, como a GLUT-1, uma vez que os achados histopatológicos sozinhos, às vezes, não são suficientes para diferenciar algumas anomalias. Além disso, a análise das expressões de marcadores envolvidos nos níveis de proliferação das lesões é um aspecto importante para o melhor entendimento do seu comportamento biológico. (AU)

Vascular anomalies constitute a distinct group of lesions, but they may present similar clinical and histopatological characteristics, which can lead to diagnostic mistakes. This study aimed by histopathology and immunohistochemical expression of human glucose transporter protein (GLUT-1), correctly identify and classify oral vascular anomalies, besides analyzing the immunoexpression of markers proliferation and apoptosis (Ki-67 and Bcl-2). All cases diagnosed as "oral hemangiomas" belonging to the archives of the Service of Pathological Anatomy from the subject of Oral Pathology of the Department of Dentistry (DOD), of the Federal University of Rio Grande do Norte (UFRN) were reviewed, totalizing 77 cases. Immunohistochemical analysis for GLUT-1 showed that only 26 (33.8%) of the specimens were true infantile hemangiomas (IHs). The 51 (66.2%%) GLUT-1 negative specimens were then reclassified as pyogenic granulomas (PGs) and vascular malformations (VMs) from their histopathologic characteristics,totalizing 26 (33.8%) cases of IHs, 20 (26.0%) of PGs and 31 (40.2) cases of oral VMs. The cases analyzed by the marker Ki-67 showed different median IH (13,85), PG (33,70) and VM (4.55) with statistically significant differences between them (p <0.001). In relation to the protein Bcl-2, the groups also showed different median of the established scores IH (1.00), PG (1.50), VMs (0.0) demonstrating statistically significant differences between them (p<0,001). No statistically significant correlation between the indexes of positivity for Ki-67 and the scores of immunoexpression of Bcl-2 were observed in any group. Thus, we can conclude that it is necessary a careful and parameterized review of cases of vascular anomalies making use of auxiliary tools such as GLUT-1, since the histopathological findings alone, sometimes, are not sufficient to differentiate some anomalies. Furthermore, analysis of the expressions of markers involved in the levels of proliferation of lesions is important for a better understanding of its biological behavior aspect. (AU)

Expression and cellular distribution of glucose transporters and alpha subunits of Na+/K+-ATPase in the heart of fructose-fed female rats: the role of estradiol.

Remarkable parallels are observed between glucose transporters (GLUT) and subunits of Na+/K+-ATPase, which deal with insulin regulation, tissue specificity, intracellular distribution and function of these proteins. To test our hypothesis that similarities also exist in alteration of cardiac GLUTs and alpha subunit isoforms of the pump in insulin resistance, animal model of fructose rich diet was exploited. The role of estradiol in regulation of GLUTs and Na+/K+-ATPase in insulin resistance context was studied as well. Cardiac protein expression, as well as insulin-regulated cellular localization of GLUT4, GLUT1, and α1 and α2 subunits of the pump were analyzed by Western blot. Fructose rich diet increased plasma insulin level and HOMA index, while estradiol treatment reversed both parameters to the control level. We did not observe obvious similarities in the pattern of alterations of GLUT1/α1 subunit of the pump, as well as GLUT4/α2 subunit, related to diet or hormone treatment. Considering alterations in expression and cellular localization of GLUTs and the pump subunits, fructose rich diet jeopardized cardiac glucose transport in some extent, but in contrast, stimulated Na+/K+-ATPase function. Estradiol treatment opposed the fructose diet biochemical action and the effect on cardiac GLUTs, but was inefficient concerning the changes of cardiac Na+/K+-ATPase subunits. Changes of the cardiac molecules can be mediated by alterations in the level of insulin and nonesterified fatty acids, induced by the diet and hormone treatment.

Expression and prognostic value of glucose transporters and hexokinases in tonsil and mobile tongue squamous cell carcinoma.

The aim of this study was to assess the expression pattern and prognostic value of the high affinity glucose transporters GLUT-1, 3, 4, 8 and 9, SGLT-1 and of hexokinases (HK) I, II and III in squamous cell carcinoma of the tonsil and mobile tongue (TTSCC) by means of immunohistochemistry. Seventy-one consecutive patients suffering from TTSCC were included. The intensity and amount of positive tumour cells in the immunoreaction (histology score (H-score)) for GLUT-1, 3, 4, 8 and 9 as well as for HK-I, II and III were assessed independently by two experienced observers, blinded to the clinical results. H-scores as well as clinical variables were related to patient outcome. Median follow-up time was 49 months (range 1-123 months). Mean H-scores for GLUT expression in decreasing order of magnitude were respectively 10.99 for GLUT-1 (sd 3.9), 5.7 for GLUT-8 (sd 4.0), 5.4 for GLUT-3 (sd 3.7), 1.0 for GLUT-4 (sd 2.0), 1.1 (sd 1.3) for SGLT-1, and 0.4 for GLUT-9 (sd 0.6); GLUT-1 > GLUT-8 = GLUT-3 > GLUT-4 = GLUT-9 = SGLT-1 (with > meaning significantly (p<0.05 on ANOVA + posthoc Bonferroni correction) higher than and =, meaning not significantly different from). Mean H-scores for hexokinase expression were respectively 5.8 for HK-I (sd 3.5), 4.6 for HK-II (sd 3.0) and 2.0 for HK-III (sd 2.0); HK-I > HK-II > HK-III. Finally high H-scores for GLUT-4 were favourably related to disease-free and overall survival on multivariate analysis. To conclude, TTSCC expresses a wide variety of glucose transporter systems and hexokinase enzymes with the "housekeeping" GLUT-1 and HK-I being the most intensely expressed. GLUT-4 over-expression appears to confer a favourable prognosis in squamous cell carcinoma of the tonsil and mobile tongue. Additional studies confirming this finding in larger cohorts of patients are mandatory.

Cellular expression of monocarboxylate transporters in the female reproductive organ of mice: implications for the genital lactate shuttle.

The present study examined the cellular localization of monocarboxylate transporters (MCTs), glucose transporters (GLUTs), and some glycolysis-related molecules in the murine female genital tract to demonstrate existence of lactate/pyruvate-dependent energy systems. MCT1, a major MCT subtype, was localized selectively in the ovarian granulosa, oviductal-ciliated cells, and vaginal epithelium; all localizations were associated with intense expressions of glycolytic enzymes. MCT1 was localized in the cell membrane of granulosa cells, including fine processes extending from cumulus cells toward oocytes. The cumulus cells and oocytes showed intense signals for lactate dehydrogenase (LDH)-A and -B, respectively. The basolateral membrane of oviductal-ciliated cells expressed MCT4 as well as MCT1, while adjacent non-ciliated cells contained an intense immunoreactivity for aldolase-C, a glycolytic enzyme. The expression of GLUTs in the ovary was generally weak with an intense expression of GLUT1 only in some vascular endothelia. The oviductal epithelium expressed GLUT1 and GLUT3, respectively, in the basolateral and apical membrane of non-ciliated cells. In the vagina, the basal layers of epithelium were immunolabeled for MCT1 with the entire length of cell membrane, and expressed abundantly both GLUT1 and LDH-A. The findings correspond well with the rich existence of lactate in the genital fluids and strongly suggest the active transport of lactate/pyruvate in the female reproductive tract, which provides favorable conditions for oocytes, sperms, and zygotes.

Insulin resistance selectively alters cell-surface glucose transporters but not their total protein expression in equine skeletal muscle.

BACKGROUND: Insulin resistance (IR) has been widely recognized in humans, and more recently in horses, but its underlying mechanisms are still not well understood. The translocation of glucose transporter 4 (GLUT4) to the cell surface is the limiting step for glucose uptake in insulin-sensitive tissues. Although the downstream signaling pathways regulating GLUT translocation are not well defined, AS160 recently has emerged as a potential key component. In addition, the role of GLUT12, one of the most recently identified insulin-sensitive GLUTs, during IR is unknown. HYPOTHESIS/OBJECTIVES: We hypothesized that cell-surface GLUT will be decreased in muscle by an AS160-dependent pathway in horses with IR. ANIMALS: Insulin-sensitive (IS) or IR mares (n = 5/group). METHODS: Muscle biopsies were performed in mares classified as IS or IR based on results of an insulin-modified frequently sampled IV glucose tolerance test. By an exofacial bis-mannose photolabeled method, we specifically quantified active cell-surface GLUT4 and GLUT12 transporters. Total GLUT4 and GLUT12 and AS160 protein expression were measured by Western blots. RESULTS: IR decreased basal cell-surface GLUT4 expression (P= .027), but not GLUT12, by an AS160-independent pathway, without affecting total GLUT4 and GLUT12 content. Cell-surface GLUT4 was not further enhanced by insulin stimulation in either group. CONCLUSIONS AND CLINICAL IMPORTANCE: IR induced defects in the skeletal muscle glucose transport pathway by decreasing active cell-surface GLUT4.