Latent and incubation periods of Delta, BA.1, and BA.2 variant cases and associated factors: a cross-sectional study in China.

BACKGROUND: The latent and incubation periods characterize the transmission of infectious viruses and are the basis for the development of outbreak prevention and control strategies. However, systematic studies on the latent period and associated factors with the incubation period for SAS-CoV-2 variants are still lacking. We inferred the two durations of Delta, BA.1, and BA.2 cases and analyzed the associated factors. METHODS: The Delta, BA.1, and BA.2 (and its lineages BA.2.2 and BA.2.76) cases with clear transmission chains and infectors from 10 local SAS-CoV-2 epidemics in China were enrolled. The latent and incubation periods were fitted by the Gamma distribution, and associated factors were analyzed using the accelerated failure time model. RESULTS: The mean latent period for 672 Delta, 208 BA.1, and 677 BA.2 cases was 4.40 (95%CI: 4.24 ~ 4.63), 2.50 (95%CI: 2.27 ~ 2.76), and 2.58 (95%CI: 2.48 ~ 2.69) days, respectively, with 85.65% (95%CI: 83.40 ~ 87.77%), 97.80% (95%CI: 96.35 ~ 98.89%), and 98.87% (95%CI: 98.40 ~ 99.27%) of them starting to shed viruses within 7 days after exposure. In 405 Delta, 75 BA.1, and 345 BA.2 symptomatic cases, the mean latent period was 0.76, 1.07, and 0.79 days shorter than the mean incubation period [5.04 (95%CI: 4.83 ~ 5.33), 3.42 (95%CI: 3.00 ~ 3.89), and 3.39 (95%CI: 3.24 ~ 3.55) days], respectively. No significant difference was observed in the two durations between BA.1 and BA.2 cases. After controlling for the sex, clinical severity, vaccination history, number of infectors, the length of exposure window and shedding window, the latent period [Delta: exp(ß) = 0.81, 95%CI: 0.66 ~ 0.98, p = 0.034; Omicron: exp(ß) = 0.82, 95%CI: 0.71 ~ 0.94, p = 0.004] and incubation period [Delta: exp(ß) = 0.69, 95%CI: 0.55 ~ 0.86, p < 0.001; Omicron: exp(ß) = 0.83, 95%CI: 0.72 ~ 0.96, p = 0.013] were significantly shorter in 18 ~ 49 years but did not change significantly in ≥ 50 years compared with 0 ~ 17 years. CONCLUSION: Pre-symptomatic transmission can occur in Delta, BA.1, and BA.2 cases. The latent and incubation periods between BA.1 and BA.2 were similar but shorter compared with Delta. Age may be associated with the latent and incubation periods of SARS-CoV-2.

Inhibition of galectin-3 ameliorates high-glucose-induced oxidative stress and inflammation in ARPE-19 cells.

PURPOSE: Retinal pigment epithelium (RPE) has been found to be participated in the pathogenesis of DR in recent years. Galectin-3 (Gal-3) is involved in many diabetic complications and ophthalmological diseases. However, the role of Gal-3 in RPE cells in DR remains unknown. This study aims to investigate the role of Gal-3 in ARPE-19 cells under high glucose treatment. MATERIALS AND METHODS: ARPE-19 cells were cultured under normal or high glucose (HG) for 48 h. Expression of Gal-3 was inhibited by Si-Gal-3 transfection. Apoptosis was checked by flow cytometry. Oxidative stress was checked by measuring ROS, MDA levels, and SOD activities. Occludin and ZO-1 expression were checked by immunofluorescence staining. Genes involved in inflammatory response were measured by real-time PCR and Western blot. RESULTS: Gal-3 expression could be increased by HG treatment in ARPE-19 cells. Gal-3 knockdown might reduce oxidative stress, apoptosis, and gene expression of VCAM-1, ICAM-1, and integrin-ß1 induced by HG treatment. The gene expression of IL-1ß could be markedly promoted by HG treatment and this increasement was partly alleviated by Gal-3 knockdown only at the mRNA level. The reduced expression of ZO-1 and occludin caused by HG could also be improved by Gal-3 knockdown. CONCLUSION: Gal-3 participated in increased oxidative stress and inflammatory response caused by HG in ARPE-19 cells.

Cladding softened fiber for sensitivity enhancement of distributed acoustic sensing.

Fiber-optic distributed acoustic sensing (DAS) technology with high spatial and strain resolutions has been widely used in many practical applications. New methods to enhance the phase sensitivity of sensing fiber are worth exploring to further improve DAS performances, although the standard single-mode fiber (SSMF) has been widely used for DAS technology. In this work, we propose and demonstrate the concept of enhancing the phase sensitivity of DAS by softening the cladding of the sensing fiber, for the first time. The theoretical analysis indicates that softening sensing fiber cladding is an effective way to improve phase sensitivity. Thus, we fabricated cladding softened fibers (CSFs) and tested their phase sensitivities experimentally. According to the results, it is found that the phase sensitivity of the CSF with 0.48 WT% phosphorus-doping concentration and 80 µm cladding diameter is 22% and 54% higher than that of the non-phosphorus-doping fiber with 80 µm cladding diameter and SSMF, respectively. The results show that by reducing fiber cladding Young's modulus with higher phosphorus-doping concentration, the DAS phase sensitivity can be enhanced effectively, verifying the theoretical analysis. Also, we found that the phase sensitivity enhancement of the sensing fiber has a linear relationship with the cladding phosphorus-doping concentration, i.e. Young's modulus. In conclusion, the reported CSF paves a way for improving the DAS phase sensitivity and would be applied to other major optical fiber sensing systems as a better sensing element over SSMF due to the enhancement in the elasto-optical effect of the sensing fiber.

Effects of neonatal dexamethasone administration on cardiac recovery ability under ischemia-reperfusion in 24-wk-old rats.

BACKGROUND: Evaluations of stress-induced cardiac functional alterations in adults after neonatal glucocorticoid (GC) treatment have been limited. In the present study, we evaluated adult cardiac functional recovery during postischemic reperfusion and measured cardiac gene expression involved energy metabolism in rats neonatally treated with dexamethasone (DEX). METHOD: Male Wistar rats were injected DEX in first 3 d after birth and controls were received saline (SAL). At 24 wk of age, insulin tolerance tests were performed, plasma lipid levels were measured, and left ventricular function and myocardial infarct size were evaluated. Expressions of genes involved in cardiac energy metabolism were measured by quantitative real-time polymerase chain reaction (PCR) and western blot. RESULTS: In 24-wk-old rats, neonatal DEX administration caused dyslipidemia, impaired cardiac recovery function and increased size of infarction, decreased cardiac expression of glucose transporter 4(GLUT4), peroxisome proliferative-activated receptor gamma coactivator 1α (PGC-1α) and ratios of phospho-forkhead box O1/forkhead box O1 (p-FoxO1/FoxO1) and phospho AMP-activated protein kinase/AMP-activated protein kinase (p-AMPK/AMPK) but increased pyruvate dehydrogenase kinase isoenzyme 4 (PDK4) expression compared with controls. CONCLUSION: Neonatal DEX administration impairs cardiac functional recovery during reperfusion following ischemia in 24-wk-old rats. Reduced cardiac glucose utilization may contribute to the long-term detrimental effects caused by neonatal DEX treatment.

Robust Indoor Human Activity Recognition Using Wireless Signals.

Wireless signals-based activity detection and recognition technology may be complementary to the existing vision-based methods, especially under the circumstance of occlusions, viewpoint change, complex background, lighting condition change, and so on. This paper explores the properties of the channel state information (CSI) of Wi-Fi signals, and presents a robust indoor daily human activity recognition framework with only one pair of transmission points (TP) and access points (AP). First of all, some indoor human actions are selected as primitive actions forming a training set. Then, an online filtering method is designed to make actions' CSI curves smooth and allow them to contain enough pattern information. Each primitive action pattern can be segmented from the outliers of its multi-input multi-output (MIMO) signals by a proposed segmentation method. Lastly, in online activities recognition, by selecting proper features and Support Vector Machine (SVM) based multi-classification, activities constituted by primitive actions can be recognized insensitive to the locations, orientations, and speeds.

Ultra-Bend-Resistant 4-Core Simplex Cable Used for Short-Reach Dense Spatial Division Multiplexing Optical Transmission.

We optimized and fabricated an ultra-bend-resistant 4-core simplex cable (SXC) employing 4-core multicore fiber (MCF) suitable for short-reach dense spatial division multiplexing (DSDM) optical transmission in the O-band. The characteristics of transmission loss, macro-bending and cross-talk (XT) between adjacent cores after cabling were firstly clarified. By introducing the trapezoid index and optimizing the cabling process, the maximum values of added XT of 1.17 dB/km due to 10 loops with a bending radius of 6 mm imposed over the 4-core SXC and a macro-bending loss of 0.37 dB/10 turns were, respectively, achieved.P Then, the optical transmission with low bit error rate (BER) was presented using a 100GBASE-LR4 transceiver over the 1.2 km long 4-core SXC. The excellent bending resistance of the 4-core SXC may pave the way for a reduction in space pressure and increase in access density on short-reach optical interconnect (OI) based on DSDM.

Progress in the study of association between hematological indicators and retinopathy of prematurity (Review).

Retinopathy of prematurity (ROP) is a retinopathy caused by abnormal proliferation of blood vessels in premature infants. It can lead to retinal detachment and, in severe cases, blindness, rendering ROP a critical condition. Advances in neonatal medicine have improved survival rates of low birth weight and low gestational age infants. However, this progress has also led to a rise in incidence of ROP. Currently, premature birth, low birth weight and high postpartum oxygen levels are independent risk factors for ROP. Other factors include mode of delivery, multiple births, anemia, blood transfusion, maternal pregnancy factors, neonatal bronchopulmonary dysplasia, use of surfactants, arterial ductus arteriosus and necrotizing enterocolitis. Laboratory indicators in premature infants such as platelet count, levels of blood glucose, inflammatory cells, lipid and hemoglobin and blood transfusion may also be associated with ROP. However, the etiology and pathogenesis of ROP are not fully understood. A number of factors may influence the onset and progression of ROP, including decreased platelet counts, decreased hemoglobin levels, increased white blood cell counts, increased blood glucose levels, and disorders of lipid metabolism. The present study reviewed the effects of platelet count, hemoglobin, blood glucose, inflammatory cells and factors, blood lipids, and plasma metabolic pathways on ROP.

Brain-Derived Exosomal CircRNAs in Plasma Serve as Diagnostic Biomarkers for Acute Ischemic Stroke.

Acute ischemic stroke (AIS), commonly known as stroke, is a debilitating condition characterized by the interruption of blood flow to the brain, resulting in tissue damage and neurological deficits. Early diagnosis is crucial for effective intervention and management, as timely treatment can significantly improve patient outcomes. Therefore, novel methods for the early diagnosis of AIS are urgently needed. Several studies have shown that bioactive molecules contained in extracellular vesicles, especially circRNAs, could be ideal markers for the diagnosis of many diseases. However, studies on the effects of exosomes and their circRNAs on the development and prognosis of AIS have not been reported extensively. Therefore, we explored the feasibility of using circRNAs in plasma brain-derived exosomes as biomarkers for AIS. By high-throughput sequencing, we first identified 358 dysregulated circRNAs (including 23 significantly upregulated circRNAs and 335 significantly downregulated circRNAs) in the plasma brain-derived exosomes of the brain infarct patient group compared to those of the noninfarct control group. Five upregulated circRNAs (hsa_circ_0007290, hsa_circ_0049637, hsa_circ_0000607, hsa_circ_0004808, and hsa_circ_0000097) were selected for further validation via Real-Time Quantitative Reverse Transcription PCR (qRT‒PCR) in a larger cohort based on the exclusion criteria of log2FC > 1, p < 0.05 and measurable expression. We found that the expression levels of hsa_circ_0007290, hsa_circ_0049637, hsa_circ_0000607, hsa_circ_0004808 and hsa_circ_0000097 were significantly upregulated in AIS patients and could serve as potential biomarkers for AIS with high specificity and sensitivity. Moreover, the expression levels of hsa_circ_0007290, hsa_circ_0049637, hsa_circ_0000607, hsa_circ_0004808 and hsa_circ_0000097 were also found to be positively correlated with National Institutes of Health Stroke Scale (NISS) and modified Rankin scale (mRS) scores, which indicated that the presence of these circRNAs in plasma brain-derived exosomes could also determine the progression of AIS.

[Endoscope-assisted repair of pediatric blowout fractures of orbital floor with autologous bone fragment].

OBJECTIVE: To explore the clinical efficacy of endoscopic repairing pediatric blowout fracture of orbital floor with autologous bone fragment. METHODS: A total of 12 cases with blowout fractures of orbital floor between March 2010 and June 2012 at Third Hospital of HeBei Medical University were reviewed. They underwent nasal endoscopic reconstruction of autologous bone fragment in situ. Medicinal biomaterial glue was used for fixation. A 6-month follow-up was performed and the therapeutic efficacies of anatomic and functional recovery were evaluated. RESULTS: No further vision loss or infection occurred postoperatively. Diplopia disappeared over a period of 3 days to 6 months. At 3 months post-operation, diplopia vanished completely (n = 9), and peripheral vision diplopia persisted (n = 3). Only 1 case had still peripheral vision diplopia at 6 months. Enophthalmos: ≥ 2 mm (n = 1), 1 mm (n = 3) for one week after surgery and only 1 mm (n = 1) at one month follow-up. Passive traction test was negative in all cases and computed tomograph (CT) revealed no bone redislocation postoperatively. CONCLUSION: Endoscopic repair of pediatric blowout fracture of orbital floor with autologous bone fragment in situ is both effective and safe.

Omentin-1 and diabetes: more evidence but far from enough.

AIMS AND BACKGROUND: Omentin-1 (oment-1) is a type of adipokines that is mainly expressed in visceral fat tissue. Based on accumulating evidence, oment-1 is closely related to diabetes and its complications. However, so far data about oment-1 and diabetes is fragmented. In this review, we focus on the role of oment-1 on diabetes, including its possible signalling pathways, the correlation of circulating omens-1 levels with diabetes and its complications. METHODS: The web of PubMed was searched for articles of relevant studies published until February, 2023. RESULTS AND CONCLUSIONS: Oment-1 might exert its effects by inhibiting the NF-κB pathway and activating the Akt and AMPK-dependent pathways. The level of circulating oment-1 is negatively correlated with the occurrence of type 2 diabetes and some complications, including diabetic vascular disease, cardiomyopathy, and retinopathy, which can be affected by anti-diabetic therapies. Oment-1 could be a promising marker for screening and targeted therapy for diabetes and its complications; however, more studies are still needed.

Updates on RPE cell damage in diabetic retinopathy (Review).

Diabetic retinopathy (DR) is a microvascular complication of diabetes. The retinal pigment epithelium (RPE) forms the outer layer of the blood­retinal barrier and serves a role in maintaining retinal function. RPE cell injury has been revealed in diabetic animal models, and high glucose (HG) levels may cause damage to RPE cells by increasing the levels of oxidative stress, promoting pro­inflammatory gene expression, disrupting cell proliferation, inducing the endothelial­mesenchymal transition, weakening tight conjunctions and elevating cell death mechanisms, such as apoptosis, ferroptosis and pyroptosis. Non­coding RNAs including microRNAs, long non­coding RNAs and circular RNAs participate in RPE cell damage caused by HG levels, which may provide targeted therapeutic strategies for the treatment of DR. Plant extracts such as citrusin and hesperidin, and a number of hypoglycemic drugs, such as sodium­glucose co­transporter 2 inhibitors, metformin and glucagon­like peptide­1 receptor agonists, exhibit potential RPE protective effects; however, the detailed mechanisms behind these effects remain to be fully elucidated. An in­depth understanding of the contribution of the RPE to DR may provide novel perspectives and therapeutic targets for DR.

Association of plasma galectin-3 and fetuin-A levels with diabetic retinopathy in type 2 diabetes mellitus patients.

INTRODUCTION: Galectin-3 (Gal-3) and fetuin-A (Fet-A) are cytokines that participate in inflammation and insulin resistance. Previous studies have found that altered Gal-3 and Fet-A levels in circulation correlate with diabetic complications. However, whether they are all associated with diabetic retinopathy (DR) has been little investigated. The aim of this study was to assess plasma Gal-3 and Fet-A concentrations, and to investigate their associations with the presence of DR in type 2 diabetes mellitus (T2DM) patients. MATERIAL AND METHODS: A total of 100 T2DM patients were enrolled, among which there were 50 patients without DR (non diabetic retinopathy, NDR group) and 50 patients with DR (DR group). Clinical parameters were collected, and plasma Gal-3 and Fet-A levels were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Both Gal-3 and Fet-A were found to be increased in DR patients with respect to NDR controls, and Gal-3 correlated positively with Fet-A. Bivariate correlation analysis revealed that Gal-3 levels were positively correlated with haemoglobin A1c (HbA1c), while Fet-A correlated negatively with fasting C peptide (FC-P) and positively with homocysteine (Hcy). Binary logistic regression suggested that elevated Gal-3 and Fet-A levels were related to increased risk of DR. ROC curve displayed that the combination of Fet-A and Gal-3 exhibited better diagnostic value for DR. CONCLUSIONS: Both Gal-3 and Fet-A were elevated in the circulation of DR patients, and they were positively associated with the occurrence of DR. The combination of 2 indicators showed better diagnostic value for DR.

A Novel Pathway of Functional microRNA Uptake and Mitochondria Delivery.

Extracellular microRNAs (miRNAs) play a critical role in horizontal gene regulation. Uptake of extracellular miRNAs by recipient cells and their intracellular transport, however, remains elusive. Here RNA phase separation is shown as a novel pathway of miRNA uptake. In the presence of serum, synthetic miRNAs rapidly self-assembly into ≈110 nm discrete nanoparticles, which enable miRNAs' entry into different cells. Depleting serum cationic proteins prevents the formation of such nanoparticles and thus blocks miRNA uptake. Different from lipofectamine-mediated miRNA transfection in which majority of miRNAs are accumulated in lysosomes of transfected cells, nanoparticles-mediated miRNA uptake predominantly delivers miRNAs into mitochondria in a polyribonucleotide nucleotidyltransferase 1(PNPT1)-dependent manner. Functional assays further show that the internalized miR-21 via miRNA phase separation enhances mitochondrial translation of cytochrome b (CYB), leading to increase in adenosine triphosphate (ATP) and reactive oxygen species (ROS) reduction in HEK293T cells. The findings thus reveal a previously unrecognized mechanism for uptake and delivery functional extracellular miRNAs into mitochondria.

Long non­coding RNA MALAT1 is involved in retinal pigment epithelial cell damage caused by high glucose treatment.

The present study aimed to explore the role of long non­coding RNA metastasis associated lung adenocarcinoma transcript 1 (lncRNA MALAT1) in high glucose (HG)­induced ARPE­19 cell damage. ARPE­19 cells were cultured and treated with HG (25 mmol/l glucose). MALAT1 expression was silenced following transfection of small interfering RNA. Cell apoptosis was measured using flow cytometry. The cellular levels of reactive oxygen species (ROS), malondialdehyde and superoxide dismutase activity were all measured to examine oxidative stress. Gene expression levels of MALAT1 were determined by reverse transcription­quantitative (RT­q)PCR, while expression of tumor necrosis factor (TNF)­α, monocyte chemotactic protein 1 (MCP­1), intercellular cell adhesion molecule 1 (ICAM­1) and vascular endothelial growth factor (VEGF) was detected using RT­qPCR and western blotting. MALAT1 expression was markedly increased in ARPE­19 cells treated with HG. HG treatment caused increased apoptosis and elevated ROS­induced stress in ARPE­19 cells and these effects could be partly attenuated by MALAT1 knockdown. Increased gene expression levels of TNF­α, MCP­1, ICAM­1 and VEGF induced by HG were also alleviated by MALAT1 inhibition. Therefore, lncRNA MALAT1 is the key factor in ARPE­19 cell damage caused by HG and may be a promising therapeutic target for clinical DR therapy. However, further studies are still required to reveal the detailed mechanisms underlying lncRNA MALAT1 function.

A novel method to purify small RNAs from human tissues for methylation analysis by LC-MS/MS.

Methylation modification of small RNAs, including miRNA, piRNA, and tsRNA, is critical for small RNA biogenesis and biological function. Methylation of individual small RNA can be defined by liquid chromatography-coupled with mass spectrometry (LC-MS/MS). However, LC-MS/MS analysis requires a high purity of individual small RNA. Due to the difficulty of purifying specific small RNA from tissues or cells, the progress in characterizing small RNA methylation by LC-MS/MS is limited. Here, we report a novel method that can efficiently purify small RNA from human tissues for LC-MS/MS analysis. This method includes two steps: 1) pull down the target small RNA by incubating total small RNAs (18-24 nt) extracted from human tissues with a biotinylated antisense oligonucleotide of the target small RNA, followed by capturing the binding duplex of biotinylated antisense and small RNA via streptavidin magnetic beads, and 2) protect the target small RNA by pairing it with a single-strand DNA, which sequence is complementary to the target small RNA, to form a DNA/RNA hybrid double-strand, followed by sequential digestion with exonuclease I, nuclease S1, and DNase I, respectively. Furthermore, employing a mixture of four pairs of synthetic methylated and non-methylated small RNAs, we further refined this two-step method by optimizing the nuclease S1 treatment condition. With this method, we successfully purified miR-21-5p, miR-26-5p, piR-020485, and tsRNA from human lung and sperm tissue samples and analyzed their 2'-O-methylation modification at the 3'-end by LC-MS/MS.

Effects of Multi-Pass Turning on Stress Corrosion Cracking of AISI 304 Austenitic Stainless Steel.

Austenitic stainless steels are extensively used in mechanical engineering. The machined surface integrity has an essential influence on the stress corrosion cracking (SCC) performance of stainless steels. In this paper, the effects of multi-pass turning on the SCC susceptibility of AISI 304 austenitic stainless steel were investigated by correlating the SCC crack density to the machining-induced surface characteristics in terms of roughness, micro-hardness, and residual stress. In the multi-pass turning, the surface roughness and residual stress were the least after the double pass turning, and the surface micro-hardness was the maximum after the triple-pass turning. The SCC susceptibility was evaluated after SCC tests in boiling MgCl2 solution. The results showed that the weakest SCC sensitivity was observed in double-pass turning 304 stainless steel, while the most susceptible SCC was found in triple-pass turning. Compared with the double-pass turning, the increase in SCC sensitivity of triple-pass turning was attributed to the larger roughness, higher micro-hardness and greater residual tensile stresses.

Fabrication and Characterization of an Optimized Low-Loss Two-Mode Fiber for Optoacoustic Sensing.

An optimized multi-step index (MSI) 2-LP-mode fiber is proposed and fabricated with low propagation loss of 0.179 dB/km, low intermodal crosstalk and excellent bend resistance. We experimentally clarified the characteristics of backward Brillouin scattering (BBS) and forward Brillouin scattering (FBS) induced by radial acoustic modes (R0,m) in the fabricated MSI 2-LP-mode fiber, respectively. Via the use of this two-mode fiber, we demonstrated a novel discriminative measurement method of temperature and acoustic impedance based on BBS and FBS, achieving improved experimental measurement uncertainties of 0.2 °C and 0.019 kg/(s·mm2) for optoacoustic chemical sensing. The low propagation loss of the sensing fiber and the new measurement method based on both BBS and FBS may pave the way for long-distance and high spatial resolution distributed fiber sensors.

[A clinical study on reparation of orbital blowout fracture by bridge hydroxylapatite artificial bone].

OBJECTIVE: To explore a minimally invasive technique with hydroxylapatite artificial bone to repair the orbital blowout fracture. METHODS: Twenty-one cases of orbital blowout fracture from March 2008 to April 2010 were enrolled. And the fractures were repaired with a bridge of hydroxylapatite artificial bone under a nasal endoscope. During a regular 6-month follow-up, anatomic and functional recovery was evaluated. RESULTS: There was neither postoperative visual loss nor infection in all cases. At 3 months post-operation, diplopia vanished completely (n = 17), remained in peripheral vision (n = 2), existed in primary ocular position (n = 2) and the deviation of eyeball (n = 1). At Month 3, diplopia in peripheral vision or in primary position and the deviation of eyeball showed no improvement. Compared with the uninjured side, enophthalmos: ≤ 2 mm (n = 18), > 2 mm (n = 2) and > 4 mm (n = 1). The passive traction test was positive in one case. On computed tomograph (CT) scanning, there was no bone dislocation or slippage in all cases. CONCLUSION: The surgical efficacy is excellent. The technique of combining the advantages of endoscopic sinus approach and hydroxyapatite artificial bone is worth a wider popularization.

SIRT1 and insulin resistance.

Sirtuin 1 (SIRT1) is a prototype mammalian NAD(+)-dependent protein deacetylase that has emerged as a key metabolic sensor in various metabolic tissues. Growing evidence suggests that SIRT1 regulates glucose and lipid metabolism through its deacetylase activity. In this review, we have summarized the recent progress in SIRT1 research with a particular focus on the role of SIRT1 in insulin resistance at different metabolic tissues. Recent data indicate that activated SIRT1 improves the insulin sensitivity of liver, skeletal muscle and adipose tissues and protects the function and cell mass of pancreatic ß-cells. These findings suggest that SIRT1 might be a new therapeutic target for the prevention of disease related to insulin resistance, such as metabolic syndrome and type 2 diabetes mellitus.