Nondiabetic Research Articles

Revolutionizing fracture fixation in diabetic and non-diabetic rats: High mobility group box 1-based coating for enhanced osseointegration.

Chronic inflammation and hyperglycemia in diabetic patients increase the risk of implant failure and impaired fracture healing. We previously developed and characterized a titanium (Ti) coating strategy using an imidazolium-based ionic liquid (IonL) with a fully reduced, non-oxidizable High Mobility Group Box 1 (HMGB1) isoform (Ti-IonL-HMGB1) to immunomodulate tissue healing. In this study, we used an open reduction fracture fixation (ORIF) model in non-diabetic (ND) and diabetic (D) rats to further investigate the effectiveness of this Ti-IonL-HMGB1 coating on orthopedic applications. Ninety male Lewis rats (12-15weeks) were divided into D (n=45) and ND (n=45) groups that were distributed into three subgroups based on the type of local treatment received: Ti (uncoated Ti), Ti-IonL, and Ti-IonL-HMGB1 implants. Fracture healing and osseointegration were evaluated using microtomographic, histological, and immunohistochemical analysis of proliferating cell nuclear antigen (PCNA), Runt-related transcription factor 2 (RUNX2), and HMGB1 markers at 2, 10, and 21days post-ORIF. Scanning Electron Microscopy verified the coating stability after placement. Microtomographic and histological analysis demonstrated increased fracture healing and osseointegration for ND rats in all treatment groups at 10days, with impaired healing for D rats. Immunohistochemical analysis exhibited elevated PCNA+ and RUNX2+ cells for D animals treated with Ti-IonL-HMGB1 at 21days compared to all other groups. The immunohistochemical marker HMGB1 was elevated at all time points for D animals in comparison to ND animals, yet was lowered for D tissues near the Ti-IonL-HMGB1 treated implant. Improved osseous healing was demonstrated in D animals with Ti-IonL-HMGB1 treatment by 21days, compared to D animals with other treatments. To the best of our knowledge, this is the first study analyzing Ti-IonL-HMGB1 implantation in an injury site through ORIF procedures in ND and D rats. This surface approach has potential for improving implanted biomaterials in diabetic environments.

Hepatic insulin synthesis increases in rat models of diabetes mellitus type 1 and 2 differently.

Insulin-positive (+) cells (IPCs), detected in multiple organs, are of great interest as a probable alternative to ameliorate pancreatic beta-cells dysfunction and insulin deficiency in diabetes. Liver is a potential source of IPCs due to it common embryological origin with pancreas. We previously demonstrated the presence of IPCs in the liver of healthy and diabetic rats, but detailed description and analysis of the factors, which potentially can induced ectopic hepatic expression of insulin in type 1 (T1D) and type 2 diabetes (T2D), were not performed. In present study we evaluate mass of hepatic IPCs in the rat models of T1D and T2D and discuss factors, which may stimulate it generation: glycaemia, organ injury, involving of hepatic stem/progenitor cell compartment, expression of transcription factors and inflammation. Quantity of IPCs in the liver was up by 1.7-fold in rats with T1D and 10-fold in T2D compared to non-diabetic (ND) rats. We concluded that ectopic hepatic expression of insulin gene is activated by combined action of a number of factors, with inflammation playing a decision role.

Circadian organization of lipid landscape is perturbed in type 2 diabetic patients

Lipid homeostasis in humans follows a diurnal pattern in muscle and pancreatic islets, altered upon metabolic dysregulation. We employ tandem and liquid-chromatography mass spectrometry to investigate daily regulation of lipid metabolism in subcutaneous white adipose tissue (SAT) and serum of type 2 diabetic (T2D) and non-diabetic (ND) human volunteers (n= 12). Around 8% of≈440 lipid metabolites exhibit diurnal rhythmicity in serum and SAT from ND and T2D subjects. The spectrum of rhythmic lipids differs between ND and T2D individuals, with the most substantial changes observed early morning, as confirmed by lipidomics in an independent cohort of ND and T2D subjects (n= 32) conducted at a single morning time point. Strikingly, metabolites identified as daily rhythmic in both serum and SAT from T2D subjects exhibit phase differences. Our study reveals massive temporal and tissue-specific alterations of human lipid homeostasis in T2D, providing essential clues for the development of lipid biomarkers in a temporal manner.

Vitreous Levels of Vascular Endothelial Growth Factor and Platelet-Derived Growth Factor in Patients with Proliferative Diabetic Retinopathy: A Clinical Correlation.

Background: The global epidemic status of diabetic retinopathy (DR) and its burden presents an ongoing challenge to health-care systems. It is of great interest to investigate potential prognostic biomarkers of DR. Such markers could aid in detecting early stages of DR, predicting DR progression and its response to therapeutics. Herein, we investigate the prognostic value of intravitreal concentrations of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) in a DR cohort. Materials and methods: Vitreous sample acquisition was conducted at King Abdullah University Hospital (KAUH) between December 2020 and June 2022. Samples were obtained from any patient scheduled to undergo a pars plana vitrectomy (PPV) for any indication. Included patients were categorized into a DR group or a corresponding non-diabetic (ND) control group. Demographics, clinicopathological variables, standardized laboratory tests results, and optical coherence tomography (OCT) data were obtained for each included individual. Intravitreal concentrations of VEGF and PDGF were assessed using commercial enzyme-linked immunosorbent assay (ELISA). Results: A total of 80 eyes from 80 patients (DR group: n = 42 and ND control group: n = 38) were included in the analysis. The vitreous VEGF levels were significantly higher in the DR group compared to the ND control group (DR group 5744.06 ± 761.5 pg/mL versus ND control group 817.94 ± 403.1 pg/mL, p = 0.0001). In addition, the vitreous PDGF levels were also significantly higher in the DR group than those in the ND control group (DR group 4031.51 ± 410.2 pg/mL versus ND control group 2691.46 ± 821.0 pg/mL, p = 0.001). Bassline differences between test groups and clinical factors impacting VEGF and PDGF concentrations were investigated as well. Multiple regression analysis indicated PDGF as the sole independent risk factor affecting best-corrected visual acuity (BCVA) at the last follow-up visit: the higher the PDGF vitreous levels, the worst the BCVA. Conclusions: Vitreous concentrations of VEGF and PDGF are correlated with DR severity and may exhibit a possible prognostic potential value in DR. Further clinical and experimental data are warranted to confirm the observed findings and to help incorporate them into daily practice.

Toward Ameliorating Insulin Resistance: Targeting a Novel PAK1 Signaling Pathway Required for Skeletal Muscle Mitochondrial Function.

The p21-activated kinase 1 (PAK1) is required for insulin-stimulated glucose uptake in skeletal muscle cells. However, whether PAK1 regulates skeletal muscle mitochondrial function, which is a central determinant of insulin sensitivity, is unknown. Here, the effect of modulating PAK1 levels (knockdown via siRNA, overexpression via adenoviral transduction, and/or inhibition of activation via IPA3) on mitochondrial function was assessed in normal and/or insulin-resistant rat L6.GLUT4myc and human muscle (LHCN-M2) myotubes. Human type 2 diabetes (T2D) and non-diabetic (ND) skeletal muscle samples were also used for validation of the identified signaling elements. PAK1 depletion in myotubes decreased mitochondrial copy number, respiration, altered mitochondrial structure, downregulated PGC1α (a core regulator of mitochondrial biogenesis and oxidative metabolism) and PGC1α activators, p38 mitogen-activated protein kinase (p38MAPK) and activating transcription factor 2 (ATF2). PAK1 enrichment in insulin-resistant myotubes improved mitochondrial function and rescued PGC1α expression levels. Activated PAK1 was localized to the cytoplasm, and PAK1 enrichment concurrent with p38MAPK inhibition did not increase PGC1α levels. PAK1 inhibition and enrichment also modified nuclear phosphorylated-ATF2 levels. T2D human samples showed a deficit for PGC1α, and PAK1 depletion in LHCN-M2 cells led to reduced mitochondrial respiration. Overall, the results suggest that PAK1 regulates muscle mitochondrial function upstream of the p38MAPK/ATF2/PGC1α-axis pathway.

Angiotensin I-converting enzyme type 2 expression is increased in pancreatic islets of type 2 diabetic donors.

Angiotensin I-converting enzyme type 2 (ACE2), a pivotal SARS-CoV-2 receptor, has been shown to be expressed in multiple cells, including human pancreatic beta-cells. A putative bidirectional relationship between SARS-CoV-2 infection and diabetes has been suggested, confirming the hypothesis that viral infection in beta-cells may lead to new-onset diabetes or worse glycometabolic control in diabetic patients. However, whether ACE2 expression levels are altered in beta-cells of diabetic patients has not yet been investigated. Here, we aimed to elucidate the in situ expression pattern of ACE2 in Type 2 diabetes (T2D) with respect to non-diabetic donors which may account for a higher susceptibility to SARS-CoV-2 infection in beta-cells. Angiotensin I-converting enzyme type 2 immunofluorescence analysis using two antibodies alongside insulin staining was performed on formalin-fixed paraffin embedded pancreatic sections obtained from n=20 T2D and n=20 non-diabetic (ND) multiorgan donors. Intensity and colocalisation analyses were performed on a total of 1082 pancreatic islets. Macrophage detection was performed using anti-CD68 immunohistochemistry on serial sections from the same donors. Using two different antibodies, ACE2 expression was confirmed in beta-cells and in pancreas microvasculature. Angiotensin I-converting enzyme type 2 expression was increased in pancreatic islets of T2D donors in comparison to ND controls alongside with a higher colocalisation rate between ACE2 and insulin using both anti-ACE2 antibodies. CD68+ cells tended to be increased in T2D pancreata, in line with higher ACE2 expression observed in serial sections. Higher ACE2 expression in T2D islets might increase their susceptibility to SARS-CoV-2 infection during COVID-19 in T2D patients, thus worsening glycometabolic outcomes and disease severity.

Changes in carotid arterial wall viscosity and carotid arterial stiffness in type 2 diabetes patients

Background and aimsChanges in arterial wall viscosity (AWW) and stiffness during type 2 diabetes (T2D) have been little investigated. We explored changes in carotid AWV considering change in arterial stiffness and loading conditions, in patients with T2D. MethodsThis cross-sectional, monocentric study compared 19 middle-aged patients with T2D to 30 non-diabetic (ND) controls. The absolute viscosity (WV) was determined as the area of the pressure-lumen cross-sectional area (P-LCSA) loop obtained by carotid tonometry and contralateral echo-tracking. The relative viscosity was determined as the ratio between WV and the elastic energy stored within the arterial wall (WV/WE). Carotid geometry, midwall stress, distensibility and elastic modulus were also compared between groups. ResultsT2D patients were older and more frequently had hypertension. Internal diameter, mean central and pulse blood pressure were higher in T2D patients but midwall stress was similar compared to ND controls. WV and WV/WE were higher in T2D patients when compared with ND controls (23 [16-41] vs. 11 [7-18] mm Hg.mm2, p=0.007 and 21% [17-25] vs. 12% [8-17], p < 0.001 respectively) even after adjustment on confounding factors. Carotid arterial stiffness was higher in T2D patients, but after adjustment this difference was only observed for the highest levels of midwall stress. ConclusionsCarotid AWV and stiffness are increased in T2D patients but only AWV is significantly increased after considering loading conditions. Whether this increase in energy dissipation within the arterial wall contributes to alter cardiovascular coupling in T2D remains to be established.

1396-P: Prevalence of Nonalcoholic Fatty Liver Disease (NAFLD) and Advanced Fibrosis among Subjects without Type 2 Diabetes (T2D)

Background: NAFLD is highly prevalent in patients with T2D. The prevalence of NAFLD in nondiabetics (ND) is not known. Aim: Assess the prevalence of NAFLD in ND subjects in the US. Methods: Data from NHANES 2017-2020 were used. NAFLD was determined by transient elastography with a CAP of ≥285 dB/m without other causes of liver disease. Significant fibrosis (SF) definition was liver stiffness measurement (LSM) &amp;gt;8.0 kPa and advanced fibrosis (AF) definition was LSM&amp;gt;13.1 kPa. Prediabetes (Pre-D) definition was fasting glucose of 100-125 mg/dL or HbA1c of 5.7%-6.5% in T2D absence. ND definition was not having T2D or Pre-D. Results: Among 5,142 patients (mean age 51.5 years, 19.4% T2D, 35.2% Pre-D and 45.4% ND). The prevalence of NAFLD among T2D, Pre-D and ND was 67.7%, 40.0% and 24.6%. As compared to Pre-D and T2D, ND patients were younger (45.6 years vs 53.4 and 62.2 years), more likely to be female (51.4% vs 43.9% and 45.3%) and less metabolically unhealthy [hypertension: 39.7% vs 56.9% and 83.9%, hyperlipidemia: 63.6%, 73.3%, and 89.0% and HOMA-IR &amp;gt; 2.5: 26.5%, 54.8%, and 84.9% (all p&amp;lt;.001)]. The prevalence of SF and AF among NAFLD with ND, Pre-D and T2D were 17.1% and 4.9%, 16.0% and 6.2%, and 32.4% and 11.8%, respectively. Factors associated with higher risk of AF varied by T2D status (Table). Conclusions: NAFLD can occur in nondiabetics and associated with insulin resistance and elevated CRP. Disclosure P. Golabi: None. J.M. Paik: None. A. Kumar: None. N. Gundurao: None. K. Cusi: Research Support; Echosens, Inventiva. Consultant; Poxel SA. Research Support; LabCorp, Zydus. Consultant; Altimmune, Arrowhead Pharmaceuticals, Inc., AstraZeneca, 89bio, Inc., Bristol-Myers Squibb Company, Lilly, Madrigal Pharmaceuticals, Inc., Merck &amp; Co., Inc., Medscape, Myovant, Novo Nordisk, ProSciento, Quest Diagnostics, Sagimet, Sonic Incytes, Terns. Z. Younossi: Consultant; AbbVie Inc., BMS, Gilead Sciences, Inc., Novo Nordisk, Merck &amp; Co., Inc., Quest Diagnostics, Siemens, Intercept Pharmaceuticals, Inc., Viking Therapeutics.

39-OR: Circulating Foamy CD36hi Ly6Clo Monocytes in Mouse Models of Diabetic Dyslipidemia

Diabetes increases the risk for cardiovascular disease (CVD) and diabetic kidney disease (DKD). Increased levels of triglyceride-rich lipoproteins (TRLs), a hallmark of diabetic dyslipidemia, associate with CVD and DKD. Monocytes become lipid-laden in response to hypercholesterolemia, but it is unclear if and how diabetic dyslipidemia induces monocyte lipid accumulation. To test if diabetes promotes foamy monocytes in circulation, we examined monocyte lipid-loading in three mouse models of diabetes with varying degrees of dyslipidemia and increases in TRLs: two mouse models of type 1 diabetes [streptozotocin (STZ)-induced diabetes (STZ-D) and viral mimicry-induced diabetes (LCMV-D)], and a model of type 2 diabetes (BTBR Lep ob;OB), all with human-like dyslipidemia generated by LDL receptor deletion. Diabetes resulted in elevated lipid loading of Ly6Clo blood monocytes in all models of diabetes, as determined by flow cytometry staining for perilipin-2 (PLN2), a marker of mature intracellular lipid droplets or BODIPY. PLN2 mean fluorescence intensity (MFI) in STZ-D was increased 1.4 ± 0.2-fold compared with nondiabetic (ND) mice, n=8-13, p=0.029, and 1.6 ± 0.1-fold in LCMV-D compared with ND mice, n=11-13, p&amp;lt;0.0001, while BODIPY was increased 2.2 ± 0.1-fold in BTBR OB vs. ND BTBR controls, n=6-11, p&amp;lt;0.0001. Moreover, Ly6Clo monocytes exhibited higher MFI of the scavenger receptor CD36 in the presence of diabetes (1.6 ± 0.2-fold in LCMV-D vs. ND, n=6, p=0.015). To further explore if diabetes increases monocyte lipid-loading via CD36, monocytes from ND and D mice were cultured with VLDL in the presence or absence of an CD36 inhibitor (sulfo-N-succinimidyl oleate). Diabetes augmented ex vivo lipid loading by VLDL, and VLDL monocyte lipid-loading was prevented by blocking CD36. These findings suggest that diabetes increases Ly6Clo monocyte CD36 levels, allowing increased lipid uptake in circulation, which may contribute to atherosclerosis and DKD. Disclosure J. Cervantes: None. F. Kramer: None. K. Bornfeldt: Advisory Panel; ESPERION Therapeutics, Inc. Other Relationship; American Heart Association. J.E. Kanter: None. Funding National Institutes of Health (R01DK121756)

585-P: Lactate Kinetics in Type 1 Diabetes—A 1-13C Lactate Study

Lactate kinetics in individuals with type 1 diabetes (T1D) has not been assessed quantitatively. Defining lactate kinetics in T1D under steady state condition is vital for estimating non-steady state lactate turnover. We studied 5 T1D and 7 nondiabetic (ND) anthropometrically matched participants during [1-13C]-sodium-lactate bolus injection in the resting, overnight fasted state. A two-compartment model with loss only from the peripheral compartment reliably described [1-13C]-lactate kinetics. Volume of distribution of the accessible compartment, V1, was similar between T1D and ND groups (40.32±21.08 vs. 47.64±33.32 mL/kg, p=0.76) thus concordant to plasma volume (~40 ml/kg). The irreversible loss from the peripheral compartment was impaired in T1D vs ND (0.08±0.03 vs. 0.13±0.03 min−1, p=0.03); rate of lactate appearance (12.4±5.2 vs. 18.5±9.6 µmol/kg/min, p=0.34), disappearance (12.7±5.2 vs. 18.8±9.7 µmol/kg/min, p=0.34) and lactate clearance (15.9±4.7 vs. 21.9±7.8 mL/kg/min, p=0.20) were numerically but not statistically lower in T1D vs. ND individuals. To conclude, we have defined lactate kinetics under resting, overnight fasted state in T1D and ND subjects. While the volume of distribution was similar in both groups, irreversible loss from the peripheral compartment was lower in T1D subjects. Further studies are needed to better define lactate kinetics during exercise in individuals with and without T1D. Disclosure D.Romeres: None. F.Ruchi: None. Y.Yadav: None. C.Cobelli: None. A.Basu: None. R.Basu: Consultant; Sparrow Pharmaceuticals Inc, Research Support; Abbott Diabetes, AstraZeneca. Funding National Institutes of Health (DK29953 to R.B.), (DK85516 to A.B.)

337-OR: Hyperglycemia Lowers Lactate Clearance during Exercise in Type 1 Diabetes

To determine the role of hyperglycemia on lactate metabolism during exercise in type 1 diabetes (T1D), we studied 7 T1D participants during two visits (EuLoI; euglycemia, low insulin; HyLoI: hyperglycemia, low insulin) in random order. 7 nondiabetic (ND) subjects were studied on one occasion (EuLoI). Lactate turnover was measured using [1-13C] lactate before, during and after 60 min of exercise at 65% VO2 max. While lactate clearance was lower (p=0.031) during exercise at HyLoI than EuLoI in T1D, it was not different between T1D and ND subjects at EuLoI (p=0.707). In contrast, rate of lactate appearance during exercise was not different between EuLoI vs. HyLoI in T1D (p=0.129), demonstrating that higher plasma lactate concentration during exercise in HyLoI (p&amp;lt;0.001) was due to reduced lactate clearance in T1D. The results from this pilot study indicates that hyperglycemia modulates lactate metabolism during exercise by lowering lactate clearance in T1D individuals. This novel observation implies that exercise during hyperglycemia can lead to higher circulating lactate concentrations thus increasing the likelihood of reaching the lactate threshold sooner, in type 1 diabetes. Disclosure D.Romeres: None. Y.Yadav: None. F.Ruchi: None. R.Carter: None. C.Cobelli: None. R.Basu: Consultant; Sparrow Pharmaceuticals Inc, Research Support; Abbott Diabetes, AstraZeneca. A.Basu: None. Funding National Institutes of Health (DK29953 to R.B.), (DK85516 to A.B.)

198-OR: Pancreatic Elastase Regulates Human Beta-Cell Viability by Impairing the PAR2 Pathway

The discovery of SerpinB1 pointed to acinar cell-derived proteases such as pancreatic elastase (PE) being involved in regulating human β-cell viability. Indeed, we observed that expression of a major form of PE, namely CELA3B, was increased in acinar cells from donors with type 2 diabetes (T2D) compared to samples from nondiabetic (ND) donors. Surprisingly, CELA3B protein levels were higher in T2D vs. ND islets, although its gene expression levels were virtually undetectable. We confirmed that increasing doses of exogenous PE is able to decrease viability and function of EndoC-βH3 (βH3) cells in vitro. To evaluate the effects of PE inhibition on β-cell survival, we used telaprevir, an FDA-approved drug, that we identified as a potent PE blocker using a High-Throughput Screening assays with an IC50 of 15.6 nM to inhibit PE activity. Consistent with the effects of SerpinB1 on β-cells, telaprevir also increased human β-cell viability in in vitro and in vivo systems. By performing phospho-antibody microarrays and single-cell RNA-Seq in human islets treated with vehicle or telaprevir, we identified the Protease-Activated Receptor 2 (PAR2) pathway as a candidate pathway linking PE inhibition to β-cell viability. We validated the results by treating EndoC-βH1 (βH1) cells with a PAR2 inactivating peptide (FSLLRY-NH2) in addition to PE +/- telaprevir. We observed that PE impaired the PAR2 cascade, and these effects were reversed by telaprevir in control β-cells, but not in cells treated with the PAR2 inhibitor. Furthermore, telaprevir was able to reverse PE effects and improve viability of control human primary β-cells, but not of those in which the PAR2 pathway was pharmacologically impaired. These data point to novel pathways reflecting acinar-β-cell crosstalk that has therapeutic potential to resolve diabetes in patients. Disclosure G. Basile: None. A. Vetere: None. J. Hu: None. D.F. De Jesus: None. A. Choudhary: None. B. Wagner: Research Support; Novo Nordisk. Stock/Shareholder; Pfizer Inc., Provention Bio, Inc. Research Support; Japan Tobacco Inc. Advisory Panel; Novo Nordisk. Research Support; Ono Pharmaceutical Co., Ltd. Stock/Shareholder; Curis, Inc. Consultant; Fresh Tracks Therapeutics. R. Kulkarni: Advisory Panel; Novo Nordisk, Inversago. Research Support; Inversago. Advisory Panel; Biomea Fusion, Inc., REDD Pharma.

1740-P: Regulation of Endocrine Cell Alternative Splicing Revealed by Single-Cell RNA Sequencing in Type 2 Diabetes

The prevalent RNA alternative splicing (AS) underlies molecular diversity, which has been demonstrated in regulating cellular functions and diseases. However, the contribution of AS in pancreatic islets remains unclear during diabetes progression. Here, we reanalyzed the full-length single-cell RNA sequencing data from the deposited database to investigate AS regulation across human pancreatic endocrine cell types in nondiabetic (ND) and type 2 diabetes (T2D) individuals. Our analysis demonstrated the significant association between AS profiles and cell-type-specificity, which could be applied to distinguish the clustering of major endocrine cell types. Moreover, AS profiles were enabled to clearly define the mature subset of β-cells in healthy controls, which was completely lost in T2D. Further analysis revealed that RNA-binding proteins (RBPs), hnRNPs and FXR1 family proteins were predicted to induce the functional impairment of β-cells through regulating AS profiles. Finally, trajectory analysis of endocrine cells suggested the β-cell identity shift through dedifferentiation and transdifferentiation of β-cells during the progression of T2D. Together, our study provides a new mechanism for regulating β-cell functions and suggests the significant contribution of AS program during diabetes. Disclosure J. Wang: None. S. Wen: None. M. Chen: None. J. Xie: None. G. Shi: None.

Characteristics of research-focused human islet preparations from organ donors with type 2 diabetes

ABSTRACT Type 2 diabetes mellitus (T2D) affects 463 million individuals worldwide. β-cell dysfunction and relatively inadequate β-cell mass has been implicated in the pathogenesis of T2D. Primary human islets from T2D patients can reveal the islet dysfunction and the underlying mechanisms and thus have become valued resources for diabetes research. Our center (Human Islet Resource Center, China) has prepared a number of batches of human islets from T2D organ donors. The present study aims to characterize islet isolation processes, islet yields, and qualities of T2D pancreases by comparing with non-diabetic (ND) ones. Overall, 24 T2D and 80 ND pancreases were obtained with informed research consents. The digestion time, islet purity, yield, size distribution, islet morphology score, viability, and function in each islet preparation were analyzed. We found that at digestion stage, T2D pancreases need significantly longer digestion duration and have worse digestion rates and lower gross islet yields. At purification stage, T2D pancreases have poorer purity, purification rate, morphology score, and islet yields after purification. Functional evaluation by GSI assay showed that the human T2D islets have significantly lower glucose stimulated insulin secretion ability. In conclusion, the features of longer digestion duration, lower yields and quality, and impaired insulin secretion in T2D group are consistent with the pathological condition of this disease. Both islet yields and islet function evaluation results did not support human T2D islets as clinical transplantation resources. However, they could serve as good research models for T2D disease studies and promote the advancement of diabetes research.

A Model Study to Evaluate Osseointegration and Fracture Healing Following Open Reduction and Internal Fixation (ORIF) in Diabetic Lewis Rats

There is a higher risk of implant osseointegration failure after open reduction and internal fixation (ORIF) in patients with diabetes due to increased inflammatory conditions, associated metallic corrosion and infection. While it is possible to avoid elective osseous surgery in patients with diabetes, it may not be the case in nonelective cases, such as ORIF ankle fractures. A total of 30 male Lewis rats (12-15 weeks old) were distributed into diabetic (D) and nondiabetic (ND) groups. Fracture healing and osseointegration were evaluated at 2-, 10-, and 21-day time points. Microtomographic and histological analysis depicted distinct differences in fracture healing and osseointegration between D and ND animals. Immunohistochemical analysis exhibited elevated proliferation (PCNA) and osteogenic (Runx2) cells for ND animals, while HMGB1 (inflammatory marker) was elevated for D animals during healing. Bone resorption marker CTX-1 was elevated in the plasma of D animals at 2 days, while bone formation marker P1NP was higher for ND animals at 10 days. Overall, this model resulted in delayed implant osseointegration and fracture healing in diabetic animals, highlighting the importance of developing new biomaterials or implant coatings that can improve bone healing outcomes in this patient population.

Anti-inflammatory and nephroprotective influence of virgin coconut oil on gentamicin‐induced nephrotoxicity in non-diabetic and streptozotocin-induced diabetic rats

Gentamicin is an effective antibiotic against severe infections, but a major downside is its nephrotoxic effects. Virgin coconut oil has potential antidiabetic effects, but there has been no study on its potential role in gentamicin‐induced nephrotoxicity in streptozotocin -induced diabetic rats. Thus, the aim of the current study is to explore the anti‐inflammatory and nephroprotective effects of virgin coconut oil on non-diabetic and streptozotocin-induced diabetic rats. A total of 48 adult male Sprague-Dawley rats were randomly divided into eight groups (n=6), including non-diabetic groups (groups 1-4) and streptozotocin-induced diabetic groups (groups 5-8). Groups 1 and 5 received a normal diet, groups 2 and 6 were fed a normal diet + gentamicin at 100 mg/kg/day for the last 10 days of the study period, groups 3 and 7 were treated with 10 ml/kg/day of virgin coconut oil for four weeks, and groups 4 and 8 were given gentamicin for the last 10 days of the study period plus virgin coconut oil for four weeks at the same doses mentioned. Gentamicin adminstaration caused oxidative stress, and led to antioxidant defense depression which was confirmed by elevated kidney Malondialdehyde (MDA) (4.53, 5.62) and reduced renal antioxidant enzymes including renal superoxide dismutase (59.82, 45.58), catalase (53.11, 37.3) and glutathione peroxidase (51.41.36.34) in non-diabetic (ND) and diabetic (D) rats, respectively. It also resulted in a significant increase of serum urea (31.72, 50.78), creatinine (2.88, 4.16), cystatin-C (13.75, 17.69), and inflammatory biomarkers interleukin-6 (IL-6) (84.01, 102.73) and tumor necrosis factor-α (TNF-α) (667.05, 853.05) in ND and D rats, respectively. Virgin coconut oil showed protective effects and significantly improved renal function parameters, including serum urea (17.35, 38.9), creatinine (1.69, 2.96) and cystatin-C (14.26, 15.94) for ND and D groups, respectively. Pre- and co-administration of virgin coconut oil exerted a remarkable protective effect against oxidative stress induced by gentamicin in normal and diabetic rats. Pro-inflammatory biomarkers were also improved in groups treated with virgin coconut oil. The results are promising in terms of the use of virgin coconut oil as a dietary agent in attenuating the progression of chronic renal disease, especially in the context of diabetes. Key words: anti‐inflammatory, nephroprotective, virgin coconut oil, gentamicin, streptozotocin, flavonoid, phenol, oxidative stress

Interleukin-4 reduces insulin secretion in human islets from healthy but not type-2 diabetic donors

Type 2 diabetes (T2D) is associated with low-grade inflammation. Here we investigate if the anti-inflammatory cytokine interleukin-4 (IL-4) affects glucose-stimulated insulin secretion (GSIS) in human islets from non-diabetic (ND) and type-2 diabetic (T2D) donors. We first confirmed that GSIS is reduced in islets from T2D donors. Treatment with IL-4 for 48 h had no further effect on GSIS in these islets but significantly reduced secretion in ND islets. Acute treatment with IL-4 for 1 h had no effect on GSIS in ND islets which led us to suspect that IL-4 affects a slow cellular mechanism such as gene transcription. IL-4 has been reported to regulate miR-378a-3p and, indeed, we found that this microRNA was increased with IL-4 treatment. However, overexpression of miR-378a-3p in the human beta cell line EndoC-βH1 did not affect GSIS. MiR-378a-3p is transcribed from the same gene as peroxisome proliferator-activated receptor gamma co-activator 1 beta (PCG-1β) and we found that IL-4 treatment showed a clear tendency to increased gene expression of PCG-1β. PCG-1β is a co-activator of peroxisome proliferator-activated receptor gamma (PPARγ) and, the gene expression of PPARγ was also increased with IL-4 treatment. Our data suggests that the protective role of IL-4 on beta cell survival comes at the cost of lowered insulin secretion, presumably involving the PPARγ-pathway.

Identification of FGF13 as a Potential Biomarker and Target for Diagnosis of Impaired Glucose Tolerance.

Early identification of pre-diabetes provides an opportunity for intervention and treatment to delay its progression to type 2 diabetes mellitus (T2DM). We aimed to identify the biomarkers of impaired glucose tolerance (IGT) through bioinformatics analysis. The GSE76896 dataset, including non-diabetic (ND), IGT, and T2DM clinical samples, was deeply analyzed to identify 309 Co-DEGs for IGT and T2DM. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that inflammatory responses and the PI3K-AKT signaling pathway are important patho-physiological features of IGT and T2DM. Protein-protein interaction (PPI) network analysis and cytoHubba technolgy identified seven hub genes: namely, CCL2, CXCL1, CXCL8, EDN1, FGF13, MMP1, and NGF. The expression and ROC curves of these hub genes were validated using the GSE38642 dataset. Through an immunofluorescence assay, we found that the expression of FGF13 in islets of mice in the HFD and T2DM groups was significantly lower than in the control group. Similarly, the level of FGF13 in the sera of IGT and T2DM patients was lower than that in the healthy group. Together, these results suggest that FGF13 can be treated as a novel biomarker of IGT, which may provide new targets for the diagnosis and treatment of pre-diabetes and T2DM.

Monitoring glucose levels in urine using FTIR spectroscopy combined with univariate and multivariate statistical methods

The development of novel platforms for non-invasive continuous glucose monitoring applied in the screening and monitoring of diabetes is crucial to improve diabetes surveillance systems. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy of urine can be an alternative as a sustainable, label-free, fast, non-invasive, and highly sensitive analysis to detect changes in urine promoted by diabetes and insulin treatment. In this study, we used ATR-FTIR to evaluate the urinary components of non-diabetic (ND), diabetic (D), and diabetic insulin-treated (D + I) rats. As expected, insulin treatment was capable to revert changes in glycemia, 24-h urine collection volume, urine creatinine, urea, and glucose excretion promoted by diabetes. Several differences in the urine spectra of ND, D, and D + I were observed, with urea, creatinine, and glucose analytes being related to these changes. Principal components analysis (PCA) scores plots allowed for the discrimination of ND and D + I from D with an accuracy of ∼ 99 %. The PCA loadings associated with PC1 confirmed the importance of urea and glucose vibrational modes for this discrimination. Univariate analysis of second derivative spectra showed a high correlation (r: 0.865, p < 0.0001) between the height of 1074 cm-1 vibrational mode with urinary glucose concentration. In order to estimate the amount of glucose present in the infrared spectra from urine, multivariate curve resolution-alternating least square (MCR-ALS) was applied and a higher predicted concentration of glucose in the urine was observed with a correlation of 78.9 % compared to urinary glucose concentration assessed using enzyme assays. In summary, ATR-FTIR combined with univariate and multivariate chemometric analyses provides an innovative, non-invasive, and sustainable approach to diabetes surveillance.

Antidiabetic and Toxicological Effects of the Tea Infusion of Summer Collection from Annona cherimola Miller Leaves

Annona cherimola Miller (Ac) is a plant used in Mexican traditional medicine for the treatment of diabetes. In this work, the tea infusion extracts obtained from 1.5 g of leaf powder from Ac collected in May (AcMa), June (AcJun), July (AcJul), and August (AcAu) were evaluated on streptozocin-induced diabetic (STID) mice and for subchronic toxicity in STID and non-diabetic (ND) mice. In addition, extracts were subjected to high-performance liquid chromatography with diode array detection (HPLC-DAD). Results showed that the tea infusion extract of the sample collected in August (AcAu) exhibited the most significant antihyperglycemic activity during all acute assays. The analysis of the extracts (AcMa, AcJu, AcJul, and AcAu) by HPLC-DAD revealed that flavonoid glycosides, rutin, narcissin, and nicotiflorin were the major components. In addition, the sample AcAu contained the best concentration of flavonoids. In the case of subchronic oral toxicity, the AcAu sample did not cause mortality in STID mice, and histopathological analysis revealed significant improvement in the changes associated with diabetes in the liver and kidneys. These findings suggest that the Ac leaves collected in August may be a source of flavonoids such as rutin, with antidiabetic potential. In addition, these findings support the use of Ac to treat diabetes in traditional medicine.