Increased SGLT1 expression in salivary gland ductal cells correlates with hyposalivation in diabetic and hypertensive rats

Background\ud Oral health complications in diabetes and hypertension include decreased salivary secretion. The sodium-glucose cotransporter 1 (SGLT1) protein, which transports 1 glucose/2 Na+/264 H2O molecules, is described in salivary glands. We hypothesized that changes in SGLT1 expression in the luminal membrane of ductal cell may be related to an altered salivary flow. \ud Findings\ud By immunohistochemistry, we investigated SGLT1 expression in ductal cells of parotid and submandibular glands from Wistar Kyoto rats (WKY), diabetic WKY (WKY-D), spontaneously hypertensive rats (SHR) and diabetic SHR (SHR-D), as well as in parotid glands from WKY subjected to sympathetic stimulation, with or without previous propranolol blockade. Diabetes and hypertension decreased the salivary secretion and increased SGLT1 expression in the luminal membrane of ductal cells, and their association exacerbated the regulations observed. After 30 min of sympathetic stimulation, SGLT1 increased in the luminal membrane of ductal cells, and that was blocked by previous injection of propranolol. \ud Conclusions\ud SGLT1 expression increases in the luminal membrane of salivary gland ductal cells and the salivary flow decreases in diabetic and hypertensive rats, which may be related to sympathetic activity. This study highlights the water transporter role of SGLT1 in salivary glands, which, by increasing ductal water reabsorption, may explain the hyposalivation of diabetic and hypertensive subjectsSao Paulo Foundation State for Research (FAPESP) 07/50554-1FAPESP, 2009/16502-

The Role of Metformin in Controlling Oxidative Stress in Muscle of Diabetic Rats

Metformin can act in muscle, inhibiting the complex I of the electron transport chain and decreasing mitochondrial reactive oxygen species. Our hypothesis is that the inhibition of complex I can minimize damage oxidative in muscles of hypoinsulinemic rats. The present study investigated the effects of insulin and/or metformin treatment on oxidative stress levels in the gastrocnemius muscle of diabetic rats. Rats were rendered diabetic (D) with an injection of streptozotocin and were submitted to treatment with insulin (D+I), metformin (D+M), or insulin plus metformin (D+I+M) for 7 days. The body weight, glycemic control, and insulin resistance were evaluated. Then, oxidative stress levels, glutathione antioxidant defense system, and antioxidant status were analyzed in the gastrocnemius muscle of hypoinsulinemic rats. The body weight decreased in D+M compared to ND rats. D+I and D+I+M rats decreased the glycemia and D+I+M rats increased the insulin sensitivity compared to D rats. D+I+M reduced the oxidative stress levels and the activity of catalase and superoxide dismutase in skeletal muscle when compared to D+I rats. In conclusion, our results reveal that dual therapy with metformin and insulin promotes more benefits to oxidative stress control in muscle of hypoinsulinemic rats than insulinotherapy alone

SGLT1 activity in lung alveolar cells of diabetic rats modulates airway surface liquid glucose concentration and bacterial proliferation

High glucose concentration in the airway surface liquid (ASL) is an important feature of diabetes that predisposes to respiratory infections. We investigated the role of alveolar epithelial SGLT1 activity on ASL glucose concentration and bacterial proliferation. Non-diabetic and diabetic rats were intranasally treated with saline, isoproterenol (to increase SGLT1 activity) or phlorizin (to decrease SGLT1 activity); 2 hours later, glucose concentration and bacterial proliferation (methicillin-resistant Sthaphylococcus aureus, MRSA and Pseudomonas aeruginosa, P. aeruginosa) were analyzed in bronchoalveolar lavage (BAL); and alveolar SGLT1 was analyzed by immunohistochemistry. BAL glucose concentration and bacterial proliferation increased in diabetic animals: isoproterenol stimulated SGLT1 migration to luminal membrane, and reduced (50%) the BAL glucose concentration; whereas phlorizin increased the BAL glucose concentration (100%). These regulations were accompanied by parallel changes of in vitro MRSA and P. aeruginosa proliferation in BAL (r = 0.9651 and r = 0.9613, respectively, Pearson correlation). The same regulations were observed in in vivo P. aeruginosa proliferation. In summary, the results indicate a relationship among SGLT1 activity, ASL glucose concentration and pulmonary bacterial proliferation. Besides, the study highlights that, in situations of pulmonary infection risk, such as in diabetic subjects, increased SGLT1 activity may prevent bacterial proliferation whereas decreased SGLT1 activity can exacerbate it.CAPESFederal University of UberlandiaFAPEMIGFAPEALFAPESPFAPEAL fellowshipUniv Fed Alagoas, Inst Biol Sci & Hlth, Alagoas, BrazilUniv Fed Sao Paulo, Dept Physiol, Sao Paulo, BrazilUniv Fed Uberlandia, Natl Reference Ctr Leprosy & Sanit Dermatol, Uberlandia, MG, BrazilUniv Sao Paulo, Inst Biomed Sci, Dept Physiol, Sao Paulo, BrazilUniv Fed Uberlandia, Inst Genet & Biochem, Uberlandia, MG, BrazilUniv Calif Davis, Dept Med Microbiol & Immunol, Davis, CA USAUniv Fed Uberlandia, Inst Biomed Sci, Dept Physiol, Uberlandia, MG, BrazilUniv Fed Sao Paulo, Dept Physiol, Sao Paulo, BrazilFAPESP: 201/04831-1Web of Scienc

Salivary molecular spectroscopy : a sustainable, rapid and non-invasive monitoring tool for diabetes mellitus during insulin treatment

Monitoring of blood glucose is an invasive, painful and costly practice in diabetes. Consequently, the search for a more cost-effective (reagent-free), non-invasive and specific diabetes monitoring method is of great interest. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy has been used in diagnosis of several diseases, however, applications in the monitoring of diabetic treatment are just beginning to emerge. Here, we used ATR-FTIR spectroscopy to evaluate saliva of non-diabetic (ND), diabetic (D) and insulin-treated diabetic (D+I) rats to identify potential salivary biomarkers related to glucose monitoring. The spectrum of saliva of ND, D and D+I rats displayed several unique vibrational modes and from these, two vibrational modes were pre-validated as potential diagnostic biomarkers by ROC curve analysis with significant correlation with glycemia. Compared to the ND and D+I rats, classification of D rats was achieved with a sensitivity of 100%, and an average specificity of 93.33% and 100% using bands 1452 cm-1 and 836 cm-1, respectively. Moreover, 1452 cm-1 and 836 cm-1 spectral bands proved to be robust spectral biomarkers and highly correlated with glycemia (R2 of 0.801 and 0.788, P < 0.01, respectively). Both PCA-LDA and HCA classifications achieved an accuracy of 95.2%. Spectral salivary biomarkers discovered using univariate and multivariate analysis may provide a novel robust alternative for diabetes monitoring using a non-invasive and green technology

Preclinical evidence implicating corticotropin-releasing factor signaling in ethanol consumption and neuroadaptation

The results of many studies support the influence of the corticotropin-releasing factor (CRF) system on ethanol (EtOH) consumption and EtOH-induced neuroadaptations that are critical in the addiction process. This review summarizes the preclinical data in this area after first providing an overview of the components of the CRF system. This complex system involves hypothalamic and extra-hypothalamic mechanisms that play a role in the central and peripheral consequences of stressors, including EtOH and other drugs of abuse. In addition, several endogenous ligands and targets make up this system and show differences in their involvement in EtOH drinking and in the effects of chronic or repeated EtOH treatment. In general, genetic and pharmacological approaches paint a consistent picture of the importance of CRF signaling via type 1 CRF receptors (CRF1) in EtOH-induced neuroadaptations that result in higher levels of intake, encourage alcohol seeking during abstinence and alter EtOH sensitivity. Furthermore, genetic findings in rodents, non-human primates and humans have provided some evidence of associations of genetic polymorphisms in CRF-related genes with EtOH drinking, although additional data are needed. These results suggest that CRF1 antagonists have potential as pharmacotherapeutics for alcohol use disorders. However, given the broad and important role of these receptors in adaptation to environmental and other challenges, full antagonist effects may be too profound and consideration should be given to treatments with modulatory effects.The authors were supported by the Department of Veterans Affairs; NIH NIAAA grants P60AA010760, R24AA020245 and U01AA013519 and NIH NIDA grant P50DA018165, during the writing of this manuscript. The authors have no financial conflict of interest to disclose

Genetic mechanisms of critical illness in COVID-19.

Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 ×  10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice

Na+/glucose cotransporter SGLT1 in the salivary glands of diabetic and hypertensive rats: role of sympathetic outflow and protein kinase A activity.

Disfunções em glândulas salivares são frequentes no diabetes e na hipertensão arterial. Glândulas salivares foram removidas para analisar o conteúdo das proteinas SGLT1 e PKA em ratos Wistar Kyoto (WKY), WKY diabéticos (WKY-D), espontaneamente hipertensos (SHR) e SHR diabéticos (SHR-D). A atividade simpática para as glândulas salivares também foi avaliada. A atividade simpática foi aumentada em SHR (P&lt;0,001) comparado com WKY; e diminuída após a induçao do diabetes em WKY and SHR (P&lt;0,05). A regulação da subunidade catalítica da PKA e da proteína SGLT1 em membrana plasmática foram paralelas com a atividade simpática. Em ratos diabéticos e/ou hipertensos, a análise da imunohistoquímica mostrou aumento da proteína SGLT1 na membrana luminal de células ductais, onde isto pode promover captação de água, reduzindo o fluxo salivar. Confirmando isso, a secreção salivar não-estimulada foi reduzida (P&lt;0,001) em WKY-D, SHR e SHR-D. Os resultados mostram que o aumento da SGLT1 luminal foi inversamente proporcional com o fluxo salivar em ratos diabéticos e hipertensos. Isto indica o papel do transporte de água da SGLT1 e, pelo aumento da reabsorção de água, pode explicar a hiposalivação em indivíduos diabéticos e hipertensos.Salivary gland dysfunction is a feature in diabetes and hypertension. In Wistar Kyoto rats (WKY), diabetic WKY (WKY-D), spontaneously hypertensive rats (SHR) and diabetic SHR (SHR-D), salivary glands were harvested for SGLT1 and PKA protein expression analysis. Moreover, sympathetic nerve activity to the salivary glands was measured. Diabetes decreased the nerve activity in WKY and SHR (P&lt;0.05), pointing out that it was higher in SHR, as compared to WKY (P&lt;0.001). The regulation of catalytic subunit of PKA and plasma membrane SGLT1 protein were parallel to the sympathetic nerve activity. In diabetic and/or hypertensive rats, imunohistochemical analysis showed increased SGLT1 protein in luminal membrane of ductal cells, where it may promote water uptake, reducing the salivary flow. Confirming that, nonstimulated salivary secretion was reduced (P&lt;0.001) in WKY-D, SHR and SHR-D rats. The results show in luminal membrane of ductal cells SGLT1 protein increased inversely proportional to the nonstimulated salivary flux in diabetic and hypertensive rats. This indicates the water transporter role of SGLT1 and, by increasing salivary water reabsorption, may explain the hyposalivation complained by diabetic subjects