Cerebellar gray matter and white matter damage among older adults with prediabetes.

AIMS: To investigate alterations in cerebrum and cerebellum in prediabetes. Cerebellar injury in diabetes is traceable, but it has not been systematically studied, and whether cerebellar injury occurs and the degree of damage in prediabetes are not known. METHODS: The current study investigated cerebral and cerebellar gray matter volume, white matter volume, white matter microstructure and white matter hyperintensity on T1-weighted, T2-weighted fluid-attenuated inversion recovery and diffusion tensor imaging scans in 78 individuals with normal glucose metabolism, 92 with prediabetes, and 108 with type 2 diabetes. RESULTS: Participants with prediabetes showed significant gray matter and white matter atrophy, microstructural damage in the cerebellar and cerebral regions. Additionally, widespread structural alterations were observed in the diabetic stage. The function of the damaged brain area was further decoded in Neurosynth, and the damaged cerebellar area with prediabetic lesions was closely related to motor function, while the area affected by diabetes was related to complex cognitive function in addition to motor function. CONCLUSIONS: Cerebellar injury had already appeared in the prediabetic stage, and cerebellar injury was aggravated in the diabetic stage; therefore, the cerebellum is a key area that is damaged early in the development of diabetes.

Metabolic Alteration Bridging the Prediabetic State and Colorectal Cancer.

Prediabetes and colorectal cancer (CRC) represent compelling health burdens responsible for high mortality and morbidity rates, sharing several modifiable risk factors. It has been hypothesized that metabolic abnormalities linking prediabetes and CRC are hyperglycemia, hyperinsulinemia, and adipokines imbalance. The chronic stimulation related to these metabolic signatures can favor CRC onset and development, as well as negatively influence CRC prognosis. To date, the growing burden of prediabetes and CRC has generated a global interest in defining their epidemiological and molecular relationships. Therefore, a deeper knowledge of the metabolic impairment determinants is compelling to identify the pathological mechanisms promoting the onset of prediabetes and CRC. In this scenario, this review aims to provide a comprehensive overview on the metabolic alterations of prediabetes and CRC as well as an overview of recent preventive and therapeutic approaches for both diseases, focusing on the role of the metabolic state as a pivotal contributor to consider for the development of future preventive and therapeutic strategies.

Transcriptomic profiling of sciatic nerves and dorsal root ganglia reveals site-specific effects of prediabetic neuropathy.

Peripheral neuropathy (PN) is a severe and frequent complication of obesity, prediabetes, and type 2 diabetes characterized by progressive distal-to-proximal peripheral nerve degeneration. However, a comprehensive understanding of the mechanisms underlying PN, and whether these mechanisms change during PN progression, is currently lacking. Here, gene expression data were obtained from distal (sciatic nerve; SCN) and proximal (dorsal root ganglia; DRG) injury sites of a high-fat diet (HFD)-induced mouse model of obesity/prediabetes at early and late disease stages. Self-organizing map and differentially expressed gene analyses followed by pathway enrichment analysis identified genes and pathways altered across disease stage and injury site. Pathways related to immune response, inflammation, and glucose and lipid metabolism were consistently dysregulated with HFD-induced PN, irrespective of injury site. However, regulation of oxidative stress was unique to the SCN while dysregulated Hippo and Notch signaling were only observed in the DRG. The role of the immune system and inflammation in disease progression was supported by an increase in the percentage of immune cells in the SCN with PN progression. Finally, when comparing these data to transcriptomic signatures from human patients with PN, we observed conserved pathways related to metabolic dysregulation across species, highlighting the translational relevance of our mouse data. Our findings demonstrate that PN is associated with distinct site-specific molecular re-programming in the peripheral nervous system, identifying novel, clinically relevant therapeutic targets.

Treatment for type 2 diabetes and diabetic nephropathy by targeting Smad3 signaling.

TGF-ß/Smad3 signaling plays a critical role in type 2 diabetes (T2D) and type 2 diabetic nephropathy (T2DN), but treatment by specifically targeting Smad3 remains unexplored. To develop a new Smad3-targeted therapy for T2D and T2DN, we treated db/db mice at the pre-diabetic or established diabetic stage with a pharmacological Smad3 inhibitor SIS3. The therapeutic effect and mechanisms of anti-Smad3 treatment on T2D and T2DN were investigated. We found that anti-Smad3 treatment on pre-diabetic db/db mice largely attenuated both T2D and T2DN by markedly reducing blood glucose levels, and inhibiting the elevated serum creatinine, microalbuminuria, and renal fibrosis and inflammation. Unexpectedly, although SIS3 treatment on the established diabetic db/db mice inhibited T2DN but did not significantly improve T2D. Mechanistically, we uncovered that inhibition of T2DN in SIS3-treated db/db mice was associated with effectively restoring the balance of TGF-ß/Smad signaling by inhibiting Smad3 while increasing Smad7, thereby suppressing Smad3-mediated renal fibrosis and NF-κB-driven renal inflammation via lncRNA Erbb4-IR and LRN9884-dependent mechanisms. We also revealed that inhibition of islet ß cell injury by preventing the loss of islet Pax 6 could be the mechanism through which the pre-diabetic treatment, rather than the late SIS3 treatment on db/db mice significantly improved the T2D phenotype.

Region-specific hippocampal atrophy is correlated with poor glycemic control in type 2 diabetes: a cross-sectional study.

To examine the association between prediabetes/type 2 diabetes mellitus (T2DM) and hippocampal subfields and to investigate the effects of glycemic control (HbA1c and FBG)/diabetes duration on the volume of hippocampal subfields in T2DM patients. This cross-sectional study included 268 participants from Tianjin Union Medical Center between August 2019 and July 2022. The participants were divided into three groups: T2DM, prediabetes and no diabetes. All participants underwent brain MRI examination on a 3T MRI scanner. FreeSurfer was performed to segment hippocampus automatically based on T1 MPRAGE images. The relationships between glycemic status/glycemic control/diabetes duration and hippocampal subfield volumes were estimated by multiple linear regression analysis/generalized additive modeling (GAM). Among all participants, 76 (28.36%) had prediabetes, and 96 (35.82%) had T2DM. In multi-adjusted linear regression models, those with prediabetes had a significantly lower volume of bilateral parasubiculum (ßright = -5.540; ßleft = -6.497). Those with diabetes had lower volume of parasubiculum (ßleft = -7.868), presubiculum-head (ßleft = -6.244) and fimbria (ßleft = -7.187). We did not find relationship between diabetes duration and hippocampal subfield volumes. In stratified analysis, long duration with high FBG related with lower volume of right fimbria (ßright = -15.583). Long duration with high HbA1c related with lower volume of presubiculum-head (ßright = -19.693), subiculum-head (ßright = -28.303), subiculum-body (ßleft = -38.599), CA1-head (ßright = -62.300, ßleft = -47.922), CA1-body (ßright = -19.043), CA4-body (ßright = -14.392), GC-ML-DG-head (ßright = -20.521), GC-ML-DG-body (ßright = -16.293, ßleft = -12.799), molecular_layer_HP-head (ßright = -44.202, ßleft = -26.071) and molecular_layer_HP-body, (ßright = -31.368), hippocampal_tail (ßleft = -80.073). Prediabetes related with lower bilateral parasubiculum volume, and T2DM related with lower left parasubiculum, presubiculum-head and fimbria. T2DM with chronic poor glycemic control had lower volume in multiple hippocampal subregions.

Magnetic resonance study of visceral, subcutaneous, liver and pancreas fat changes after 12 weeks intermittent fasting in obese participants with prediabetes.

BACKGROUND: It is not clear whether there are differences in proportions of fat loss from visceral:subcutaneous depots by probiotic supplementation, ethnicity or sex during weight loss; or whether visceral/pancreatic fat depot changes are related to changes in HbA1c. Our objective is to investigate whether weight loss from different fat depots is related to these factors during weight loss achieved by intermittent fasting. METHOD: Prediabetes participants on 5:2 intermittent fasting were randomized 1:1 to either daily probiotic or placebo for 12 weeks. Twenty-four patients had magnetic resonance imaging data at baseline and 12 weeks. RESULTS: After 12 weeks of intermittent fasting, subcutaneous fat (%) changed from 35.9 ± 3.1 to 34.4 ± 3.2, visceral fat (%) from 15.8 ± 1.3 to 14.8 ± 1.2, liver fat (%) from 8.7 ± 0.8 to 7.5 ± 0.7 and pancreatic fat (%) from 7.7 ± 0.5 to 6.5 ± 0.5 (all p < 0.001). Changes in weight, HbA1c, SAT, VAT, LF and PF did not differ significantly between probiotic and placebo groups. CONCLUSION: Overall weight loss was correlated with fat loss from subcutaneous depots. Losses from different fat depots did not correlate with changes in HbA1c or differ by probiotic supplementation, ethnicity or sex.

Trajectories of glycaemic traits exhibit sex-specific associations with hepatic iron and fat content: Results from the KORA-MRI study.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) represents a major disease burden in the population. While the bidirectional association between NAFLD and diabetes is established, little is known about the association of hepatic iron content and glycaemia. Moreover, analyses of sex-specific effects and of dynamic changes in glycaemia are scarce. METHODS: We investigated 7-year sex-specific trajectories of glycaemia and related traits (HbA1c, fasting glucose, fasting insulin, HOMA-IR, 2-h glucose and cross-sectional 2-h insulin) in a sample from a population-based cohort (N = 365; 41.1% female). Hepatic iron and fat content were assessed by 3T-Magnetic Resonance Imaging (MRI). Two-step multi-level models adjusted for glucose-lowering medication and confounders were applied. RESULTS: In women and men, markers of glucose metabolism correlated with hepatic iron and fat content. Deterioration of glycaemia was associated with increased hepatic iron content in men (normoglycaemia to prediabetes: beta = 2.21 s-1 , 95% CI [0.47, 3.95]). Additionally, deterioration of glycaemia (e.g. prediabetes to diabetes: 1.27 log(%), [0.84, 1.70]) and trajectories of glucose, insulin and HOMA-IR were significantly associated with hepatic fat content in men. Similarly, deterioration of glycaemia as well as trajectories of glucose, insulin and HOMA-IR was significantly associated with increased hepatic fat content in women (e.g. trajectory of fasting insulin: 0.63 log(%), [0.36, 0.90]). CONCLUSIONS: Unfavourable 7-year trajectories of markers of glucose metabolism are associated with increased hepatic fat content, particularly in women, whereas the association with hepatic iron content was less clear. Monitoring changes of glycaemia in the sub-diabetic range might enable early identification of hepatic iron overload and steatosis.

Macular and peripapillary retinal nerve fiber layer thinning in eyes with prediabetes in the elderly population: OTASSHA study.

PURPOSE: To investigate retinal thickness parameters in the elderly with prediabetes mellitus (preDM) and type 2 DM without retinopathy (non-diabetic retinopathy [NDR]). METHODS: This cross-sectional study included a total of 1273 eyes without retinal pathologies of 699 volunteers aged ≥ 65 years were included. The eyes were categorized into non-DM (606 eyes), preDM (480 eyes), and NDR (187 eyes) groups according to their HbA1c levels. Fundus photography, swept-source optical coherence tomography, and comprehensive systemic examination were conducted. The thicknesses of the retinal nerve fiber layer in the macula (mRNFL) and peripapillary (pRNFL), ganglion cell complex (GCC), and ganglion cell inner plexiform layer (GCIPL), as well as central subfield thickness (CST) and central foveal thickness (CFT) were investigated for their association with DM stage using linear mixed model. RESULTS: A statistically significant thinning of mRNFL was observed in preDM vs. non-DM and in NDR vs. preDM in 3/6 sectors. A significant thinning of pRNFL was observed in preDM vs. non-DM and in NDR vs. preDM in 2/12 sectors. Such DM stage-dependent thinning of RNFL was observed mainly in the temporal and superior sectors. GCIPL and GCC were less sensitive to reflect DM-dependent inner retinal thinning. CST and CFT were not significantly associated with different DM stages. CONCLUSION: The thinning of mRNFL in the temporal and superior sectors might be a sensitive parameter associated with early neurodegeneration in preDM and NDR.

Comprehensive study of the rheological status and intensity of oxidative stress during the progression of type 2 diabetes mellitus to prevent its complications.

BACKGROUND: Prevention of Type 2 diabetes mellitus (T2DM) requires a modifying effect on the pathological processes inducing the ß-cell dysfunction. OBJECTIVES: the comprehensive study of the violation of rheological parameters in patients with different stages of diabetes and identification of possible links between these alterations with the intensity of the oxidative stress in the patient's body. METHODS: 60 patients with IR, prediabetes, T2DM and healthy volunteers were included. Full range of the rheological parameters of the patients' blood - the indicators of erythrocytes aggregation index (EAI), the relative deformability of the erythrocytes membranes (ERDI), blood plasma viscosity (BPV), and oxidative stress intensity (OSI) were examined. RESULTS: In patients with insulin resistance (IR), prediabetes, and T2DM the ERDI was statistically significantly lower and BPV - higher compared to control; a significant increase in EAI was detected in the patient group with prediabetes and T2DM compared to the control. CONCLUSION: The level of rheological disorders in patients increases with the increase of the level of carbohydrate metabolism disorders and intensity of oxidative stress and reaches a maximum during manifested diabetes. Diagnosis of hemorheological disorders and OSI in T2DM can serve as an early marker of target organ damage possibility.

Accelerated amyloid angiopathy and related vascular alterations in a mixed murine model of Alzheimer´s disease and type two diabetes.

BACKGROUND: While aging is the main risk factor for Alzheimer´s disease (AD), emerging evidence suggests that metabolic alterations such as type 2 diabetes (T2D) are also major contributors. Indeed, several studies have described a close relationship between AD and T2D with clinical evidence showing that both diseases coexist. A hallmark pathological event in AD is amyloid-ß (Aß) deposition in the brain as either amyloid plaques or around leptomeningeal and cortical arterioles, thus constituting cerebral amyloid angiopathy (CAA). CAA is observed in 85-95% of autopsy cases with AD and it contributes to AD pathology by limiting perivascular drainage of Aß. METHODS: To further explore these alterations when AD and T2D coexist, we have used in vivo multiphoton microscopy to analyze over time the Aß deposition in the form of plaques and CAA in a relevant model of AD (APPswe/PS1dE9) combined with T2D (db/db). We have simultaneously assessed the effects of high-fat diet-induced prediabetes in AD mice. Since both plaques and CAA are implicated in oxidative-stress mediated vascular damage in the brain, as well as in the activation of matrix metalloproteinases (MMP), we have also analyzed oxidative stress by Amplex Red oxidation, MMP activity by DQ™ Gelatin, and vascular functionality. RESULTS: We found that prediabetes accelerates amyloid plaque and CAA deposition, suggesting that initial metabolic alterations may directly affect AD pathology. T2D significantly affects vascular pathology and CAA deposition, which is increased in AD-T2D mice, suggesting that T2D favors vascular accumulation of Aß. Moreover, T2D synergistically contributes to increase CAA mediated oxidative stress and MMP activation, affecting red blood cell velocity. CONCLUSIONS: Our data support the cross-talk between metabolic disease and Aß deposition that affects vascular integrity, ultimately contributing to AD pathology and related functional changes in the brain microvasculature.

The pancreatic exocrine function in patients with pancreatic endocrine insufficiency: the evaluation with cine-dynamic magnetic resonance cholangiopancreatography using a spatially selective inversion-recovery pulse and T1 mapping.

PURPOSE: To evaluate the association of the pancreatic exocrine function estimated by cine-dynamic magnetic resonance cholangiopancreatography (MRCP) using a spatially selective inversion-recovery (IR) pulse with the pancreatic endocrine function estimated by the T1 relaxation time of the pancreatic parenchyma and HbA1c values. MATERIALS AND METHODS: Forty-three patients with suspected hepatobiliary or pancreatic diseases were included. Patients were classified into three groups: HbA1c < 5.7% (normal group), 5.7% ≤ HbA1c < 6.5% (prediabetes group), and HbA1c ≥ 6.5% (diabetes group). The frequency of the secretory flow of the pancreatic juice was observed within the area of the IR pulse, and the moving distance (mean secretion grade) of the pancreatic juice inflow within the area of the IR pulse on cine-dynamic MRCP, and the T1 relaxation time of the pancreatic parenchyma on the T1 map images were assessed. The MR imaging measurements were compared using Spearman's rank correlation coefficient analysis and the Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Both the mean secretion grade and frequency of the pancreatic secretory inflow had a significant negative correlation with the T1 relaxation time of the pancreatic parenchyma (r = - 0.335, p = 0.028 and r = - 0.305, p = 0.047, respectively) and HbA1c values (r = - 0.308, p = 0.044 and r = - 0.313, p = 0.041, respectively). Both the mean secretion grade and frequency of the pancreatic secretory inflow in the elevated HbA1c (prediabetes and diabetes) group were significantly lower than those in the normal group (p = 0.030 and p = 0.029, respectively). CONCLUSION: The pancreatic exocrine function estimated by cine-dynamic MRCP was significantly lower in patients with prediabetes and diabetes than in controls. Cine-dynamic MRCP with a spatially selective IR pulse may be useful for the early diagnosis of pancreatic exocrine insufficiency in patients with pancreatic endocrine insufficiency.

Association of MRI-based adrenal gland volume and impaired glucose metabolism in a population-based cohort study.

OBJECTIVES: The aim of this study was to assess adrenal gland volume by using magnetic resonance imaging (MRI) and to study its role as an indirect marker of impaired glucose metabolism and hypothalamic-pituitary-adrenal (HPA) axis activation in a population-based cohort. METHODS: Asymptomatic participants were enrolled in a nested case-control study and underwent a 3-T MRI, including T1w-VIBE-Dixon sequences. For the assessment of adrenal gland volume, adrenal glands were manually segmented in a blinded fashion. Impaired glucose metabolism was determined using fasting glucose and oral glucose tolerance test. Cardiometabolic risk factors were also obtained. Inter- and intrareader reliability as well as univariate and multivariate associations were derived. RESULTS: Among 375 subjects included in the analysis (58.5% male, 56.1 ± 9.1 years), 25.3% participants had prediabetes and 13.6% had type 2 diabetes (T2DM). Total adrenal gland volume was 11.2 ± 4.2 ml and differed significantly between impaired glucose metabolism and healthy controls with largest total adrenal gland volume in T2DM (healthy controls: 10.0 ± 3.9 ml, prediabetes: 12.5 ± 3.8 ml, T2DM: 13.9 ± 4.6 ml; p < 0.001). In the multivariate analysis, association of T2DM and increased adrenal gland volume was independent of age, sex, hypertension, triglycerides and body mass index (BMI), but was attenuated in subjects with prediabetes after adjustment for BMI. CONCLUSIONS: T2DM is significantly associated with increased adrenal gland volume by MRI in an asymptomatic cohort, independent of age, sex, dyslipidaemia, hypertension and BMI. Adrenal gland volume may represent an indirect marker of impaired glucose metabolism and HPA axis dysfunction.

ASSOCIATION OF PREDIABETES WITH RETINAL MICROVASCULATURE ON SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN THE ELDERLY: OTASSHA Study.

PURPOSE: To investigate the retinal microvasculature in the elderly persons with prediabetes mellitus (preDM) and type 2 DM. METHODS: This cross-sectional study included a total of 452 eyes without retinal pathologies of 301 elderly volunteers aged ≥65 years, and they were categorized into nonDM (225 eyes), preDM (177 eyes), and DM (50 eyes) groups based on their HbA1c. Fundus photography, swept-source optical coherence tomography and angiography, and comprehensive systemic examinations were conducted. Vessel density (VD) and foveal avascular zone in superficial and deep retinal microvasculature were investigated for their association with DM stages using linear mixed model. RESULTS: Superficial VD (sVD) mean values in nonDM, preDM, and DM groups were 35.2%, 34.9%, and 34.8%, respectively. sVD in preDM was equivalent to sVD in DM, whereas significantly lower compared with sVD in nonDM (difference [95% CI] -0.19 [-0.33 to -0.049], P = 0.009). Deep VD (dVD) mean values in nonDM, preDM, and DM groups were 35.0%, 35.0%, and 34.4%, respectively. dVD in preDM was equivalent to dVD in nonDM, whereas significantly higher compared with dVD in DM (difference [95% CI] 0.31 [0.046-0.57], P = 0.02). There was no significant association between foveal avascular zone area and DM stages. CONCLUSION: Retinal microvasculature may be affected at the prediabetic stage in the elderly.

L6H21 protects against cognitive impairment and brain pathologies via toll-like receptor 4-myeloid differentiation factor 2 signalling in prediabetic rats.

BACKGROUND AND PURPOSE: Chronic high-fat diet (HFD) intake instigates prediabetes and brain pathologies, which include cognitive decline and neuroinflammation. The myeloid differentiation factor 2 (MD-2)/toll-like receptor 4 (TLR4) complex plays a pivotal role in neuroinflammation. The MD-2 inhibitor (L6H21) reduces systemic inflammation and metabolic disturbances in HFD-induced prediabetes. However, the potential role of L6H21, and its comparison with metformin, on brain pathologies in HFD-induced prediabetes has never been investigated. EXPERIMENTAL APPROACH: Male Wistar rats were given either a normal diet (ND) (n = 8) or a HFD (n = 104) for 16 weeks. At the 13th week, ND-fed rats were given a vehicle, whereas HFD-fed rats were randomly divided into 13 subgroups. Each subgroup was given vehicle, L6H21 (three doses) or metformin (300-mg·kg-1 ·day-1 ) for 1, 2 or 4 weeks. Metabolic parameters, cognitive function, brain mitochondrial function, brain TLR4-MD-2 signalling, microglial morphology, brain oxidative stress, brain cell death and dendritic spine density were investigated. KEY RESULTS: HFD-fed rats developed prediabetes, neuroinflammation, brain pathologies and cognitive impairment. All doses of L6H21 and metformin given to HFD-fed rats at 2 and 4 weeks attenuated metabolic disturbance. CONCLUSION AND IMPLICATIONS: In rats, L6H21 and metformin restored cognition and attenuated brain pathologies dose and time-dependently. These results indicate a neuroprotective role of MD-2 inhibitor in a model of prediabetes.

High Throughput Study for Molecular Mechanism of Metformin Pre-Diabetic Protection via Microarray Approach.

BACKGROUND: Metformin is a biguanide that exhibits antidiabetic, anticarcinogenic, and anti-inflammatory properties. Despite well-known pancreatic protective effects, metformin's influence on pancreatic islet ß-cell is yet considerably unknown. Protecting the functional insulin-producing ß-cells in the pancreas is a key therapeutic challenge in patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM). OBJECTIVE: The current study aimed to analyze the protective effects of metformin on streptozocin- induced diabetic rats in T1DM in hepatic tissues. METHODS: In the present study, male Wistar rats (n=24) were randomly assigned into 2 groups (n=12 for each control and test), and metformin (100 mg/kg/day) was given for 7 weeks. Afterward, diabetes was induced by streptozocin (STZ) at a single dose of 150 mg/kg. Blood glucose was examined daily before and after STZ induction. The animals were euthanized by cervical dislocation 5 days after streptozocin injection, after which liver and pancreas were harvested from each rat. RESULTS: The biochemical analyses revealed that metformin resulted in significantly reduced plasma glucose levels and higher pancreatic insulin levels in the test group. Using a restrictive cut-off of at least 2-FC and an adjusted p-value (q-value) of ≤0.05, a sum of 747 genes for the metformin group were shown to be differentially regulated compared to controls (320 Down and 427 Up), by which they were obtained from the liver. Furthermore, the evidence is attained that metformin may hinder the loss of critical ß-cells by reducing inflammatory and apoptosis signaling, promoting fatty acid ß-oxidation, and inducing metabolism. CONCLUSION: Collectively, this study has demonstrated a decrease in blood glucose levels and a rise in insulin-levels and thus consequent prophylactic effects in metformin-given STZ-induced diabetic rats.

Association of Mixed Use of Electronic and Conventional Cigarettes and Exposure to Secondhand Smoke With Prediabetes.

CONTEXT: Despite previous studies regarding the association between smoking and diabetes, the effects of electronic cigarettes and secondhand smoke (SHS) on glucose metabolism and insulin sensitivity have not been fully elucidated. OBJECTIVE: To examine the association of mixed electronic and conventional cigarette use and exposure to SHS with prediabetes. DESIGN: Data from the 2014-2018 Korean National Health and Nutrition Examination Survey were analyzed. SETTING: Nationwide population-based. PARTICIPANTS: Of 39 199 participants, 22 385 participants (9490 men, 12 895 women) without diabetes were included. The main independent variables were smoking behaviors, including exposure to SHS. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Prediabetes (hemoglobin A1C of 5.7-6.4%). RESULTS: Of 22 385 participants without diabetes, 6735 had prediabetes. Mixed cigarette use was associated with a 1.57-fold increase in the odds of prediabetes when compared with never-smoking [odds ratio (OR) = 1.57, 95% CI = 1.29-1.92] and a 1.27-fold increase when compared with conventional cigarette use only (OR = 1.27, 95% CI = 1.07-1.52). Participants who were current nonsmokers, but mixed users in the past had an increased risk of prediabetes (OR = 1.54, 95% CI = 1.04-2.13). There was no significant association between prediabetes and current nonsmoking in individuals with previous conventional cigarette use only. Among never-smokers, exposure to SHS significantly increased the risk of prediabetes (OR = 1.16, 95% CI = 1.04-1.30). CONCLUSIONS: Mixed use of electronic and conventional cigarettes and exposure to SHS increased the risk of prediabetes. Further studies are required to comprehensively investigate the molecular biology underlying the effects of previous and current mixed use of electronic cigarettes and SHS on glucose metabolism.

Metabolomic Profile of Skeletal Muscle and Its Change Under a Mixed-Mode Exercise Intervention in Progressively Dysglycemic Subjects.

Skeletal muscles play an essential role in whole-body glucose homeostasis. They are a key organ system engaged in the development of insulin resistance, and also a crucial tissue mediating the beneficial metabolic effects of physical activity. However, molecular mechanisms underlying both these processes in skeletal muscle remain unclear. The aim of our study was to compare metabolomic profiles in skeletal muscle of patients at different stages of dysglycemia, from normoglycemia through prediabetes to T2D, and its changes under a mixed-mode (strength and endurance) exercise intervention. We performed targeted metabolomics comprising several major metabolite classes, including amino acids, biogenic amines and lipid subgroups in skeletal muscles of male patients. Dysglycemic groups differed significantly at baseline in lysophosphatidylcholines, phosphatidylcholines, sphingomyelins, glutamine, ornithine, and carnosine. Following the exercise intervention, we detected significant changes in lipids and metabolites related to lipid metabolism, including in ceramides and acylcarnitines. With their larger and more significant change over the intervention and among dysglycemic groups, these findings suggest that lipid species may play a predominant role in both the pathogenesis of type 2 diabetes and its protection by exercise. Simultaneously, we demonstrated that amino acid metabolism, especially glutamate dysregulation, is correlated to the development of insulin resistance and parallels disturbances in lipid metabolites.

Redefining the Role of ADAM17 in Renal Proximal Tubular Cells and Its Implications in an Obese Mouse Model of Pre-Diabetes.

Acute and chronic kidney lesions induce an increase in A Disintegrin And Metalloproteinase domain 17 (ADAM17) that cleaves several transmembrane proteins related to inflammatory and fibrotic pathways. Our group has demonstrated that renal ADAM17 is upregulated in diabetic mice and its inhibition decreases renal inflammation and fibrosis. The purpose of the present study was to analyze how Adam17 deletion in proximal tubules affects different renal structures in an obese mice model. Tubular Adam17 knockout male mice and their controls were fed a high-fat diet (HFD) for 22 weeks. Glucose tolerance, urinary albumin-to-creatinine ratio, renal histology, and pro-inflammatory and pro-fibrotic markers were evaluated. Results showed that wild-type mice fed an HFD became obese with glucose intolerance and renal histological alterations mimicking a pre-diabetic condition; consequently, greater glomerular size and mesangial expansion were observed. Adam17 tubular deletion improved glucose tolerance and protected animals against glomerular injury and prevented podocyte loss in HFD mice. In addition, HFD mice showed more glomerular macrophages and collagen accumulation, which was prevented by Adam17 deletion. Galectin-3 expression increased in the proximal tubules and glomeruli of HFD mice and ameliorated with Adam17 deletion. In conclusion, Adam17 in proximal tubules influences glucose tolerance and participates in the kidney injury in an obese pre-diabetic murine model. The role of ADAM17 in the tubule impacts on glomerular inflammation and fibrosis.

The Response of Mitochondrial Respiration and Quantity in Skeletal Muscle and Adipose Tissue to Exercise in Humans with Prediabetes.

BACKGROUND: Mitochondrial dysfunction has been implicated in the pathogenesis of type 2 diabetes, but its contribution to the early stages of dysglycemia remains poorly understood. By collecting a high-resolution stage-based spectrum of dysglycemia, our study fills this gap by evaluating derangement in both the function and quantity of mitochondria. We sampled mitochondria in skeletal muscle and subcutaneous adipose tissues of subjects with progressive advancement of dysglycemia under a three-month exercise intervention. METHODS: We measured clinical metabolic parameters and gathered skeletal muscle and adipose tissue biopsies before and after the three-month exercise intervention. We then assayed the number of mitochondria via citrate synthase (CS) activity and functional parameters with high-resolution respirometry. RESULTS: In muscle, there were no differences in mitochondrial quantity or function at baseline between normoglycemics and prediabetics. However, the intervention caused improvement in CS activity, implying an increase in mitochondrial quantity. By contrast in adipose tissue, baseline differences in CS activity were present, with the lowest CS activity coincident with impaired fasting glucose and impaired glucose tolerance (IFG + IGT). Finally, CS activity, but few of the functional metrics, improved under the intervention. CONCLUSIONS: We show that in prediabetes, no differences in the function or amount of mitochondria (measured by CS activity) in skeletal muscle are apparent, but in adipose tissue of subjects with IFG + IGT, a significantly reduced activity of CS was observed. Finally, metabolic improvements under the exercise correlate to improvements in the amount, rather than function, of mitochondria in both tissues.

A Narrative Review of Human Clinical Trials on the Impact of Phenolic-Rich Plant Extracts on Prediabetes and Its Subgroups.

Phenolic-rich plant extracts have been demonstrated to improve glycemic control in individuals with prediabetes. However, there is increasing evidence that people with prediabetes are not a homogeneous group but exhibit different glycemic profiles leading to the existence of prediabetes subgroups. Prediabetes subgroups have been identified as: isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), and combined impaired fasting glucose and glucose intolerance (IFG/IGT). The present review investigates human clinical trials examining the hypoglycemic potential of phenolic-rich plant extracts in prediabetes and prediabetes subgroups. Artemisia princeps Pampanini, soy (Glycine max (L.) Merrill) leaf and Citrus junos Tanaka peel have been demonstrated to improve fasting glycemia and thus may be more useful for individuals with IFG with increasing hepatic insulin resistance. In contrast, white mulberry (Morus alba Linn.) leaf, persimmon (Diospyros kaki) leaf and Acacia. Mearnsii bark were shown to improve postprandial glycemia and hence may be preferably beneficial for individuals with IGT with increasing muscle insulin resistance. Elaeis guineensis leaf was observed to improve both fasting and postprandial glycemic measures depending on the dose. Current evidence remains scarce regarding the impact of the plant extracts on glycemic control in prediabetes subgroups and therefore warrants further study.