Streptozotocin-Induced Diabetic Models in Mice and Rats

On-demand Opto-Laser activatable nanoSilver ThermoGel for treatment of full-thickness diabetic wound in a mouse model

Patients suffering from diabetes mellitus are prone to develop diabetic wounds that are non-treatable with conventional therapies. Hence, there is an urgent need of hour to develop the therapy that will overcome the lacunas of conventional therapies. This investigation reports the Quality by Design-guided one-pot green synthesis of unique Opto-Laser activatable nanoSilver ThermoGel (OL→nSil-ThermoGel) for hyperthermia-assisted treatment of full-thickness diabetic wounds in mice models. The characterization findings confirmed the formation of spherical-shaped nanometric Opto-Laser activatable nanoSilver (30.75 ± 2.7 nm; ∆T: 37 ± 0.2 °C → 66.2 ± 0.1 °C; at 1.8 W/cm2 NIR laser density). The findings indicated acceptable in vitro cytocompatibility and significant keratinocyte migration (95.04 ± 0.07 %) activity of OL→nSil towards HaCaT cells. The rheological data of OL→nSil hybridized in situ thermoresponsive gel (OL→nSil-ThermoGel) showed the gelling temperature at 32 ± 2 °C. In vivo studies on full-thickness diabetic wounds in a Mouse model showed OL→nSil-ThermoGel accelerated wound closure (94.42 ± 1.03 %) and increased collagen synthesis, angiogenesis, and decreased inflammatory markers. Similarly, immunohistochemistry study showed significant angiogenesis and faster phenotypic switching of fibroblasts to myofibroblasts in OL→nSil-ThermoGel treated diabetic wounds. Histological evaluation revealed a marked rise in keratinocyte migration, organized collagen deposition, and early regeneration of the epithelial layer compared to the diabetic wound control. In conclusion, the OL→nSil-ThermoGel modulates the cytokines, re-epithelialization, protein expression, and growth factors, thereby improving the repair and regeneration of diabetic wounds in mice.

Hyperglycemia sensitizes female mice to stress-induced depressive-like behavior in an inflammation-independent manner

BACKGROUND

Depression is a multifaceted disorder that represents one of the most common causes of disability. The risk for developing depression is increased in women and among individuals with chronic diseases. For example, individuals in the United States with diabetes mellitus (DM) are at a twofold increased risk of developing depression compared to the general population and approximately one-quarter of women with diabetes have comorbid depression. The neurobiological mechanisms underlying this association between diabetes and depression is not fully understood and is particularly under-investigated in female models. We sought to explore the role of neuroinflammation in diabetes-induced depression in a female mouse model of hyperglycemia.

METHODS

To this end, we utilized female C57BL/6 J mice to (1) characterize the depressive-like symptoms in response to 75 mg/kg/day dose of streptozotocin (STZ) over 5 days, a dose reported to induce hyperglycemia in female mice (n=20), (2) determine if female hyperglycemic mice are sensitized to unpredictable chronic mild stress (UCMS)-induced depressive-like behavior and neuroinflammation (n=28), and (3) investigate if female hyperglycemic mice are primed to respond to a subthreshold dose of lipopolysaccharide (LPS), an acute inflammatory challenge (n=21).

RESULTS

Our results demonstrate that female mice exhibit robust hyperglycemia but limited evidence of depressive-like behavior in response to 75 mg/kg STZ. Additionally, we observe that healthy female mice have limited response to our stress protocol; however, hyperglycemic mice display increased stress-sensitivity as indicated by increased immobility in the forced swim test. While STZ mice show evidence of mild neuroinflammation, this effect was blunted by stress. Further, STZ mice failed to display a sensitization to inflammation-induced depressive-like behavior.

CONCLUSION

We interpret this data to indicate that while STZ-induced hyperglycemia does increase vulnerability to stress-induced depressive-like behavior, this effect is not a consequence of neuroinflammatory priming. Future studies will seek to better understand the mechanisms underlying this sensitization.

Therapeutic effect of Momordica charantia on cardiomyopathy in a diabetic maternal rat model

Myocardial structural and functional abnormalities are hallmarks of diabetic cardiomyopathy (DCM), a chronic consequence of diabetes mellitus (DM). Maternal DM affects and increases the risk of heart defects in diabetic mothers compared with nondiabetic mothers. Momordica charantia exhibits antidiabetic effects due to various bioactive compounds that are phytochemicals, a broad group that includes phenolic compounds, alkaloids, proteins, steroids, inorganic compounds, and lipids. Pregnant maternal rats were split into four groups: control (C), M. charantia-treated (MC), type 2 diabetes mellitus (T2DM) (DM), and diabetic (MC + DM) groups. Diabetes mothers had increased serum glucose, insulin, total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels and reduced high-density lipoprotein cholesterol levels. Cardiac biomarkers such as cardiac troponin T (cTnT), creatine kinase-myocardial band (CK-MB), and lactate dehydrogenase were increased. Hormone levels of follicle-stimulating hormone, luteinizing hormone, progesterone, and estrogen decreased significantly. Inflammatory markers such as interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and vascular adhesion molecule-1 (VCAM-1) were elevated in diabetic mothers. Oxidative stress markers indicated increased malondialdehyde and nitric oxide levels, while antioxidants such as glutathione, superoxide dismutase, and catalase were decreased in maternal heart tissue. The levels of apoptotic markers such as tumor suppressor 53 (P53) and cysteine aspartic protease-3 (caspase-3) were significantly greater in diabetic maternal heart tissue. Histopathological analysis revealed heart tissue abnormalities in diabetic maternal rats. M. charantia extract improved maternal diabetes-induced changes in inflammation, antioxidant levels, and heart tissue structure.

Er-Dong-Xiao-Ke decoction regulates lipid metabolism via PPARG-mediated UCP2/AMPK signaling to alleviate diabetic meibomian gland dysfunction

ETHNOPHARMACOLOGICAL RELEVANCE

Meibomian gland dysfunction (MGD), complicated by type 2 diabetes, is associated with a high incidence of ocular surface disease, and no effective drug treatment exists. Diabetes mellitus (DM) MGD shows a notable disturbance in lipid metabolism. Er-Dong-Xiao-Ke decoction (EDXKD) has important functions in nourishing yin, clearing heat, and removing blood stasis, which are effective in the treatment of DM MGD.

AIM OF THE STUDY

To observe the therapeutic effect of EDXKD on DM MGD and its underlying molecular mechanism.

MATERIALS AND METHODS

After establishing a type 2 DM (T2DM)-induced MGD rat model, different doses of EDXKD and T0070907 were administered. The chemical constituents of EDXKD were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the molecular mechanism of EDXKD in treating DM MGD was predicted using network pharmacology. Lipid metabolism in DM meibomian glands (MGs) was analyzed using LC-MS/MS, and lipid biomarkers were screened and identified. Histological changes and lipid accumulation in MGs were detected by staining, and Peroxisome proliferator-activated receptor gamma (PPARG) expression in MG acinar cells was detected by immunofluorescence. The expression of lipid metabolism-related factors was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) or western blotting.

RESULTS

EDXKD reduced lipid accumulation in the MGs and improved the ocular surface index in DM MGD rats. The main active components of EDXKD had advantages in lipid regulation. Additionally, the PPARG signaling pathway was the key pathway of EDXKD in the treatment of DM MGD. Twelve lipid metabolites were biomarkers of EDXKD in the treatment of DM MGD, and glycerophospholipid metabolism was the main pathway of lipid regulation. Moreover, EDXKD improved lipid deposition in the acini and upregulated the expression of PPARG. Further, EDXKD regulated the PPARG-mediated UCP2/AMPK signaling network, inhibited lipid production, and promoted lipid transport.

CONCLUSION

EDXKD is an effective treatment for MGD in patients with T2DM. EDXKD can regulate lipids by regulating the PPARG-mediated UCP2/AMPK signaling network, as it reduced lipid accumulation in the MGs of DM MGD rats, promoted lipid metabolism, and improved MG function and ocular surface indices.

Jinmaitong alleviates diabetic neuropathic pain by inhibiting JAK2/STAT3 signaling in microglia of diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Jinmaitong (JMT) is a prescription of Traditional Chinese Medicine that is composed of 12 crude drugs. It has been used in the treatment of diabetic neuropathic pain (DNP) for more than 30 years.

AIM OF STUDY

Microglia are thought to play an important role in neuropathic pain. This study aimed to evaluate the protective effect of JMT against DNP and to investigate the underlying mechanisms in which the microglia and JAK2/STAT3 signaling pathway were mainly involved.

MATERIALS AND METHODS

The chemical composition of JMT was analyzed using liquid chromatography tandem mass spectrometry. The diabetes model was constructed using 11 to 12-week-old male Zucker diabetic fatty (ZDF) rat (fa/fa). The model rats were divided into 5 groups and were given JMT at three dosages (11.6, 23.2, and 46.4 g/kg, respectively, calculated as the crude drug materials), JAK inhibitor AG490 (positive drug, 10 μg/day), and placebo (deionized water), respectively, for eight weeks (n = 6). Meanwhile, Zucker lean controls (fa/+) were given a placebo (n = 6). Body weight was tested weekly and blood glucose was monitored every 2 weeks. The mechanical allodynia and heat hyperalgesia were assessed using mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) tests. After treatment, the microglia activation marker Iba-1, CD11B, CD68, neuroinflammatory mediators, and mediators of the JAK2/STAT3 signaling pathway were compared between different groups. The mRNA and protein levels of target genes were assessed by quantitative real-time PCR and Western Blot, respectively.

RESULTS

We found that JMT significantly inhibited the overactivation of microglia in spinal cords, and suppressed neuroinflammation of DNP model rats, thereby ameliorating neurological dysfunction and injuries. Furthermore, these effects of JMT could be attributed to the inhibition of the JAK2/STAT3 signaling pathway.

CONCLUSIONS

Our findings suggested that JMT effectively ameliorated DNP by modulating microglia activation via inhibition of the JAK2/STAT3 signaling pathway. The present study provided a basis for further research on the therapeutic strategies of DNP.

Effect of cuproptosis on acute kidney injury after cardiopulmonary bypass in diabetic patients

BACKGROUND

Cardiopulmonary bypass (CPB) is a common procedure in cardiac surgery. CPB is a high-risk factor for acute kidney injury (AKI), and diabetes is also such a factor. Diabetes can lead to copper overload. It is currently unclear whether AKI after CPB in diabetic patients is related to copper overload.

AIM

To explore whether the occurrence of CPB-AKI in diabetic patients is associated with cuproptosis.

METHODS

Blood and urine were collected from clinical diabetic and non-diabetic patients before and after CPB. Levels of copper ion, lactate, glucose, heat shock protein-70 (HSP-70), and dihydrolipoamide dehydrogenase (DLAT) were determined. A diabetic rat model was established and CPB was performed. The rats were assessed for the development of CPB-AKI, and for the association of AKI with cuproptosis by detecting copper levels, iron-sulfur cluster proteins and observation of mitochondrial structure by electron microscopy.

RESULTS

CPB resulted in elevations of copper, lactate, HSP-70 and DLAT in blood and urine in both diabetic and non-diabetic patients. CPB was associated with pathologic and mitochondrial damage in the kidneys of diabetic rats. Cuproptosis-related proteins also appeared to be significantly reduced.

CONCLUSION

CPB-AKI is associated with cuproptosis. Diabetes mellitus is an important factor aggravating CPB-AKI and cuproptosis.

Skin keratinocyte-derived SIRT1 and BDNF modulate mechanical allodynia in mouse models of diabetic neuropathy

Diabetic neuropathy is a debilitating disorder characterized by spontaneous and mechanical allodynia. The role of skin mechanoreceptors in the development of mechanical allodynia is unclear. We discovered that mice with diabetic neuropathy had decreased sirtuin 1 (SIRT1) deacetylase activity in foot skin, leading to reduced expression of brain-derived neurotrophic factor (BDNF) and subsequent loss of innervation in Meissner corpuscles, a mechanoreceptor expressing the BDNF receptor TrkB. When SIRT1 was depleted from skin, the mechanical allodynia worsened in diabetic neuropathy mice, likely due to retrograde degeneration of the Meissner-corpuscle innervating Aβ axons and aberrant formation of Meissner corpuscles which may have increased the mechanosensitivity. The same phenomenon was also noted in skin-keratinocyte specific BDNF knockout mice. Furthermore, overexpression of SIRT1 in skin induced Meissner corpuscle reinnervation and regeneration, resulting in significant improvement of diabetic mechanical allodynia. Overall, the findings suggested that skin-derived SIRT1 and BDNF function in the same pathway in skin sensory apparatus regeneration and highlighted the potential of developing topical SIRT1-activating compounds as a novel treatment for diabetic mechanical allodynia.

The effects of ecdysterone and enalapril on nitric oxide synthesis and the markers of oxidative stress in streptozotocin-induced diabetes in rats: a comparative study

Cardiovascular functions in diabetes greatly depend on constitutive NOS (cNOS) activity. A comparative study of the effects of a steroid hormone ecdysterone and enalapril, an ACE inhibitor widely used to treat cardiac disorders on cNOS, inducible NOS (iNOS), xanthine oxidoreductase (XOR) activity, RNS, ROS, and lipid peroxidation in heart tissue in experimental diabetes was conducted. The rat model of diabetes was established by streptozotocin injection. NOS activity, NO2-, NO3-, uric acid, nitrosothiols, hydroperoxide, superoxide, and diene conjugate formation were studied spectrophotomerically. In diabetes, cNOS downregulation correlated with a dramatic fall of NO2- production and ~4.5-fold elevation of nitrosothiols, which agreed with a steep rise of iNOS activity, while NO3- remained close to control. Dramatic activation of XOR was observed, which correlated with the elevation of both superoxide production and nitrate reductase activity and resulted in strong lipid peroxidation. Ecdysterone and enalapril differently affected RNS metabolism. Ecdysterone moderately restored cNOS but strongly suppressed iNOS, which resulted in the reduction of NO3-, but full restoration of NO2- production. Enalapril better restored cNOS but less effectively suppressed iNOS, which promoted NO3- formation. Both drugs similarly inhibited XOR, which equally alleviated oxidative stress and lipid peroxidation. The synergistic action of iNOS and XOR was a plausible explanation for strong lipid peroxidation, abolished by the inhibition of iNOS and XOR by ecdysterone or enalapril. Complementary effects of ecdysterone and enalapril on cNOS, iNOS, and RNS are a promising basis for their combined use in the treatment of cardiovascular disorders caused by cNOS dysfunction in diabetes.

Role of LRP5/6/GSK-3β/β-catenin in the differences in exenatide- and insulin-promoted T2D osteogenesis and osteomodulation

BACKGROUND AND PURPOSE

Insulin and exenatide are two hypoglycaemic agents that exhibit different osteogenic effects. This study compared the differences between exenatide and insulin in osseointegration in a rat model of Type 2 diabetes (T2D) and explored the mechanisms promoting osteogenesis in this model of T2D.

EXPERIMENTAL APPROACH

In vivo, micro-CT was used to detect differences in the peri-implant bone microstructure in vivo. Histology, dual-fluorescent labelling, immunofluorescence and immunohistochemistry were used to detect differences in tissue, cell and protein expression around the implants. In vitro, RT-PCR and western blotting were used to measure the expression of osteogenesis- and Wnt signalling-related genes and proteins in bone marrow mesenchymal stromal cells (BMSCs) from rats with T2D (TBMSCs) after PBS, insulin and exenatide treatment. RT-PCR was used to detect the expression of Wnt bypass cascade reactions under Wnt inactivation.

KEY RESULTS

Micro-CT and section staining showed exenatide extensively promoted peri-implant osseointegration. Both in vivo and in vitro experiments showed exenatide substantially increased the expression of osteogenesis-related and activated the LRP5/6/GSK-3β/β-catenin-related Wnt pathway. Furthermore, exenatide suppressed expression of Bmpr1a to inhibit lipogenesis and promoted expression of Btrc to suppress inflammation.

CONCLUSION AND IMPLICATIONS

Compared to insulin, exenatide significantly improved osteogenesis in T2D rats and TBMSCs. In addition to its dependence on LRP5/6/GSK-3β/β-catenin signalling for osteogenic differentiation, exenatide-mediated osteomodulation also involves inhibition of inflammation and adipogenesis by BMPR1A and β-TrCP, respectively.

Treatment with Blackberry Extract and Metformin in Sporadic Alzheimer's Disease Model: Impact on Memory, Inflammation, Redox Status, Phosphorylated Tau Protein and Insulin Signaling

Natural products offer promising potential for the development of new therapies for Alzheimer's disease (AD). Blackberry fruits are rich in phytochemical compounds capable of modulating pathways involved in neuroprotection. Additionally, drug repurposing and repositioning could also accelerate the development of news treatments for AD. In light of the reduced brain glucose metabolism in AD, an alternative approach has been the use of the drug metformin. Thus, the aim of this study was to evaluate the effect of treatment with blackberry extract in a model of AD induced by streptozotocin (STZ) and compare it with metformin treatment. Male rats were divided into groups: I - Control; II - STZ; III - STZ + blackberry extract (100 mg/kg); IV - STZ + blackberry extract (200 mg/kg) and V - STZ + metformin (150 mg/kg). The animals received intracerebroventricular injection of STZ or buffer. Seven days after the surgical procedure, the animals were treated orally with blackberry extract or metformin for 21 days. Blackberry extract and metformin prevented the memory impairment induced by STZ. In animals of group II, an increase in acetylcholinesterase activity, phosphorylated tau protein, IL-6, oxidative damage, and gene expression of GSK-3β and Nrf2 was observed in the hippocampus. STZ induced a decrease in IL-10 levels and down-regulated the gene expression of Akt1, IRS-1 and FOXO3a. Blackberry extract and metformin prevented the alterations in acetylcholinesterase activity, IL-6, GSK3β, Nrf2, and oxidative damage. In conclusion, blackberry extract exhibits multi-target actions in a model of AD, suggesting new therapeutic potentials for this neurodegenerative disease.

Inhibition of CYP1A1 expression enhances diabetic wound healing by modulating inflammation and oxidative stress in a rat model

OBJECTIVE

Wound therapies utilizing gene delivery to the skin offer considerable promise owing to their localized treatment benefits and straightforward application. This study investigated the impact of skin electroporation of CYP1A1 shRNA lentiviral particles on diabetic wound healing in a streptozotocin (STZ)-induced rat model.

METHODS

Male Sprague Dawley (SD) rats were made diabetic by injecting STZ and subsequently creating foot skin wounds. The rats were randomly divided into four groups: normal, diabetic foot ulcers (DFU), DFU + control shRNA (electroporation of control shRNA lentiviral particles), and DFU + CYP1A1 shRNA (electroporation of CYP1A1 shRNA lentiviral particles). Wound healing progress was monitored at multiple time points (0, 1, 3, 5, 7, 10, 14 days). On day 14, wound tissue specimens were collected for histological examination. Wound samples collected at days 7 and 14 were used for gene expression analysis via qRT-PCR, assessment of CYP1A1 protein levels using western blotting, and evaluation of oxidative stress markers.

RESULTS

Treatment with CYP1A1 shRNA significantly enhanced diabetic wound healing rates compared to untreated controls over the observation period. Histological analysis revealed improved wound characteristics in the CYP1A1 shRNA-treated group, including enhanced epithelial regeneration, reduced inflammation, and increased collagen deposition, indicative of improved tissue repair. Furthermore, suppression of CYP1A1 corresponded with decreased expression levels of pro-inflammatory cytokines (interleukin-1β, tumor necrosis factor-α, and interleukin-6) and diminished oxidative stress markers (malondialdehyde, superoxide dismutase) within wound tissues.

CONCLUSION

Targeted suppression of CYP1A1 represents a promising therapeutic strategy to enhance diabetic wound healing by modulating inflammation and oxidative stress.

Diabetes Mellitus Inhibits Hair Follicle Regeneration by Inducing Macrophage Reprogramming-Mediated Pyroptosis

Background

Diabetes mellitus (DM) is known to inhibit skin self-renewal and hair follicle stem cell (HFSC) activation, which may be key in the formation of chronic diabetic wounds. This study aimed to investigate the reasons behind the suppression of HFSC activation in DM mice.

Methods

Type 1 DM (T1DM) was induced in 6-week-old mice via streptozotocin, and hair follicle growth was subsequently monitored. RNA sequencing, bioinformatics analyses, qRT‒PCR, immunostaining, and cellular experiments were carried out to investigate the underlying mechanisms involved.

Results

T1DM inhibited HFSC activation, which correlated with an increase in caspase-dependent programmed cell death. Additionally, T1DM triggered apoptosis and pyroptosis, predominantly in HFSCs and epidermal regions, with pyroptosis being more pronounced in the inner root sheath of hair follicles. Notably, significant cutaneous immune imbalances were observed, particularly in macrophages. Cellular experiments demonstrated that M1 macrophages inhibited HaCaT cell proliferation and induced cell death, whereas high-glucose environments alone did not have the same effect.

Conclusion

T1DM inhibits HFSC activation via macrophage reprogramming-mediated caspase-dependent pyroptosis, and there is a significant regional characterization of cell death. Moreover, T1DM-induced programmed cell death in the skin may be more closely related to immune homeostasis imbalance than to hyperglycemia itself. These findings shed light on the pathogenesis of diabetic ulcers and provide a theoretical basis for the use of hair follicle grafts in wound repair.

Upregulation of GRP78 is accompanied by decreased antioxidant response and mitophagy promotion in streptozotocin-induced type 1 diabetes in rats

Endoplasmic reticulum stress, oxidative stress, and mitochondrial dysfunction are interconnected processes involved in the pathogenesis of diabetes mellitus (DM). In the present study, we demonstrate a distinct unfolded protein response (UPR) signaling pathways in two mammalian models of DM: β-TC-6 cell line and streptozotocin-induced type 1 diabetes model in rats. However, a feature common to both systems was the upregulation of the GRP78 protein. Moreover, in vivo studies showed the disruption of the antioxidant system and an escalation of mitophagy against the background of a depletion of the level of ATP in pancreatic cells. In conclusion, we suggest that glucotoxic conditions induced GRP78 upregulation, and next cause depletion of the antioxidant pool and disruption of the functioning of antioxidant defense enzymes and in consequence promote mitophagy in pancreatic cells. Therefore, GRP78 may be considered as a potential therapeutic factor in patients with diabetes.

Determination of beneficial effects of cuminaldehyde on hyperglycemia associated kidney malfunctions

Type 1 diabetes mellitus is defined by the autoimmune destruction of pancreatic β cells, with diabetic nephropathy being a significant consequence. Recently, cuminaldehyde has been shown protective ability against various pathophysiology. However, its nephroprotective and anti-diabetic potential has not yet been fully understood. We, therefore, conducted the present study to evaluate the anti-hyperglycemic potential of cuminaldehyde in NRK52E cells without (control) or with high glucose medium to emulate hyperglycemic conditions. Cuminaldehyde pre-treatment at an optimal concentration of 175 μM prior to high glucose addition restricted excessive reactive oxygen species (ROS) production and maintained cellular morphology to almost normal. The inhibitor study using N-acetyl-l-cysteine confirmed that blocking of ROS assists NRK52E cells in evading apoptosis. In addition, hyperglycemia was induced in 6-week-old Swiss albino mice in this investigation through the intraperitoneal injection of streptozotocin (150 mg kg-1 body weight). Hyperglycemia increased the kidney-to-body weight ratio, lowered serum insulin levels, and led to significant renal tissue damage compared to control mice. Moreover, hyperglycemia disturbs cellular redox equilibrium by decreasing antioxidant enzyme functions and promoting inflammatory cytokines in kidney tissue. Administering cuminaldehyde at a dosage of 10 mg kg-1 body weight for 5 weeks daily after the onset of diabetes effectively ameliorated the aforementioned anomalies and reversed kidney damage by regulating inflammation-induced cell death. Overall, the research demonstrated that cuminaldehyde has hypoglycemic, antioxidant, anti-inflammatory, and anti-apoptotic properties. We believe that after conducting extensive research, this unique molecule can be used in clinical trials against diabetic nephropathy in future.

Recent Insights into Roles of Hypoxia-Inducible Factors in Retinal Diseases

Hypoxia-inducible factors (HIFs) are transcriptional factors that function as strong regulators of oxygen homeostasis and cellular metabolisms. The maintenance of cellular oxygen levels is critical as either insufficient or excessive oxygen affects development and physiologic and pathologic conditions. In the eye, retinas have a high metabolic demand for oxygen. Retinal ischemia can cause visual impairment in various sight-threating disorders including age-related macular degeneration, diabetic retinopathy, and some types of glaucoma. Therefore, understanding the potential roles of HIFs in the retina is highly important for managing disease development and progression. This review focuses on the physiologic and pathologic roles of HIFs as regulators of oxygen homeostasis and cellular metabolism in the retina, drawing on recent evidence. Our summary will promote comprehensive approaches to targeting HIFs for therapeutic purposes in retinal diseases.

Longitudinal Analysis of Bone Metabolic Markers and Bone Mechanical Properties in STZ-Induced Diabetic Rats

Background: This longitudinal study examined the early effects of type 1 diabetes on bone mechanical properties and metabolic markers in mature rats, focusing on the natural progression of diabetes-induced changes without external treatments. Methods: Forty-eight 8-month-old male Wistar rats were divided into two groups, with one group receiving a single dose of streptozotocin (STZ, 60 mg/kg). Assessments were performed 2, 4, and 8 weeks post-administration, including serum biochemical analyses, bone marker assessments, and mechanical bone tests. The data were analyzed using two-way ANOVA to evaluate the impact of time and treatment. Results: At 2 weeks, diabetic rats showed increased fasting blood glucose (p < 0.001), decreased insulin levels (p = 0.03), and changes in HOMA markers (p < 0.001), liver enzymes (p < 0.001), inflammatory markers (p < 0.001), and bone metabolism markers (osteocalcin (p < 0.001), OPG (p = 0.006), RANKL (p < 0.001), and OPG/RANKL ratio (p < 0.001)), with initial alterations in bone geometry. By week 4, decreased body weight in the diabetic group (p < 0.001) led to further changes in bone geometry and initial differences in mechanical properties. At 8 weeks, significant declines in body (p < 0.001) and bone (p < 0.001) weights were observed, along with further deterioration in bone geometry and mechanical properties. Conclusions: The study highlights the significant impact of STZ-induced diabetes on bone health as early as two weeks post-STZ administration, with marked temporal changes in biochemical markers and mechanical properties.

Flavokawain B is an effective natural peroxisome proliferator-activated receptor γ-selective agonist with a strong glucose-lowering effect

Rosiglitazone, a full PPARγ agonist and a classical insulin sensitizer, was once used as a powerful weapon in the treatment of T2DM. However, its applications have been restricted recently because of its multiple side effects. Here, a natural compound, flavokawain B (FKB), which was screened in our previous experiments, was investigated for its potential as a preferable insulin sensitizer because it has no or few side effects. Using the surface plasmon resonance (SPR) technique, we confirmed that FKB is a natural ligand for PPARγ with high binding affinity. In in vitro experiments, FKB significantly increased 2-NBDG uptake in HepG2 and 3 T3-L1 cells, which partially stimulated PPARγ transcriptional activity. Compared with rosiglitazone, FKB had little effect on the adipose differentiation of 3 T3-L1 cells, and all of these features suggest that FKB is a selective modulator of PPARγ (SPPARγM). Moreover, FKB increased the mRNA expression levels of most genes related to insulin sensitivity and glucose metabolism but had no obvious effect on those related to adipose differentiation. In vivo experiments confirmed that FKB effectively decreased abnormal fasting blood glucose and postprandial blood glucose levels and reduced glycated hemoglobin levels, similar to rosiglitazone, in HFD-fed/STZ-treated and db/db mice, two T2DM animal models, but did not cause side effects, such as weight gain or liver or kidney damage. Further investigation revealed that FKB could inhibit PPARγ-Ser273 phosphorylation, which is the key mechanism involved in improving insulin resistance. Together, FKB is a well-performing SPPARγM that exerts a powerful glucose-lowering effect without causing the same side effects as rosiglitazone, and it may have great potential for development.

Modulation of the Cardiovascular Risk in Type 1 Diabetic Rats by Endurance Training in Combination with the Prebiotic Xylooligosaccharide

Diabetic cardiomyopathy is a major etiological factor in heart failure in diabetic patients, characterized by mitochondrial oxidative metabolism dysfunction, myocardial fibrosis, and marked glycogen elevation. The aim of the present study is to evaluate the effect of endurance training and prebiotic xylooligosaccharide (XOS) on the activity of key oxidative enzymes, myocardial collagen, and glycogen distribution as well as some serum biochemical risk markers in streptozotocin-induced type 1 diabetic rats. Male Wistar rats (n = 36) were divided into four diabetic groups (n = 9): sedentary diabetic rats on a normal diet (SDN), trained diabetic rats on a normal diet (TDN), trained diabetic rats on a normal diet with an XOS supplement (TD-XOS), and sedentary diabetic rats with an XOS supplement (SD-XOS). The results show that aerobic training managed to increase the enzyme activity of respiratory Complex I and II and the lactate dehydrogenase in the cardiomyocytes of the diabetic rats. Furthermore, the combination of exercise and XOS significantly decreased the collagen and glycogen content. No significant effects on blood pressure, heart rate or markers of inflammation were detected. These results demonstrate the beneficial effects of exercise, alone or in combination with XOS, on the cardiac mitochondrial enzymology and histopathology of diabetic rats.

Bionic sulfated glycosaminoglycan-based hydrogel inspired by snail mucus promotes diabetic chronic wound healing via regulating macrophage polarization

The treatment of diabetic foot ulcers remains a significant challenge, as their morbidity is increasing while current therapies are expensive and often ineffective. The dried mucus from the snail Achatina fulica promotes diabetic wound healing. Herein, to develop a more controllable and stable wound dressing for diabetic wound treatment, the AFG/StarPEG hydrogel mimicking snail mucus was prepared by covalently coupling of sulfated glycosaminoglycan from A. fulica (AFG) with star-shaped polyethylene glycol (StarPEG) amine. The AFG/StarPEG hydrogel reduced excessive inflammation in wound tissues by decreasing pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) and increasing anti-inflammatory cytokines (IL-4 and IL-10). Moreover, it promoted the polarization of macrophages to M2 anti-inflammatory type in diabetic wound. By improving transition of diabetic chronic wound from inflammatory phase to proliferative phase, it promoted angiogenesis, collagen deposition and re-epithelialization, and thus tissue regeneration for wound healing. This work provides a convenient and effective dressing for treating chronic diabetic wound.

Effects of Some Olive Fruits-Derived Products on Oxidative Stress and Cardiovascular Biomarkers on Experimental Diabetes Mellitus

The aim of this study is to assess the possible effect of olive seed oil (OSO) and destoned and dehydrated olive oil (DDOO), in comparison with extra-virgin olive oil (EVOO), on some cardiovascular biomarkers in an experimental model of diabetes mellitus. Diabetic animals showed evident alterations in biomarkers involved in the evolution of diabetic vasculopathy, marked by increases in biomarkers that favor vascular damage, which was between 1.5 and five times as many as those in non-diabetic animals, and a smaller number of biomarkers that protect against such damage (25-75% less than in healthy controls) was observed. The three oils administered decreased the concentration of biomarkers of vascular damage (35-45% in the serum lipid profile, 15-40% in early biomarkers of vascular inflammation and 20-60% in platelet aggregation and in thromboxane/prostacyclin imbalance). The greatest effect was by the antioxidant, both in the inhibition of lipid peroxidation and in the increase of glutathione. DDOO showed a significantly greater effect on oxidative stress and on thromboxane/prostacyclin imbalance than those shown by OSO and EVOO. This greater effect may possibly be explained by its higher triterpenoid content (913 mg/kg, compared to 113 mg/kg in OSO and 75 mg/kg in EVOO). We conclude, in the light of the results of this study, that these oils meet two basic conditions: they could improve the yield of the olive industry, and they equal, and may even increase, the beneficial effects of EVOO on cardiovascular disease.

Quercetin prevents rats from type 1 diabetic liver damage by inhibiting TGF-ꞵ/apelin gene expression

Background

Hyperglycemia-induced oxidative stress is a significant contributor to diabetic complications, including hepatopathy. The current survey aimed to evaluate the ameliorative effect of quercetin (Q) on liver functional disorders and tissue damage developed by diabetes mellitus in rats.

Methods

Grouping of 35 male Wistar rats was performed as follows: sham; sham + quercetin (sham + Q: quercetin, 50 mg/kg/day in 1 ml 1% DMSO for 6 weeks, by gavage); diabetic control (Diabetes: streptozotocin (STZ), 65 mg/kg, i.p.); diabetic + quercetin 1 (D + Q1: quercetin, 25 mg/kg/day in 1 ml 1% DMSO for 6 weeks, by gavage after STZ injection); and diabetic + quercetin 2 (D + Q2: quercetin, 50 mg/kg/day in 1 ml 1% DMSO for 6 weeks, by gavage after STZ injection). Body weight, food intake, and water intake were measured. Ultimately, the samples of plasma and urine, as well as tissue samples of the liver and pancreas were gathered for later assays.

Results

STZ injection ended in elevated plasma blood glucose levels, decreased plasma insulin levels, liver dysfunction (increased activity levels of AST, ALT, and ALP, increased plasma levels of total bilirubin, cholesterol, LDL, triglyceride, decreased plasma levels of total protein, albumin and HDL), enhanced levels of malondialdehyde, diminished activities of antioxidant enzymes (superoxide dismutase, and catalase), reduced level of glutathione (GSH) increased gene expression levels of apelin and TGF-ꞵ, plus liver histological destruction. All these changes were diminished by quercetin. However, the measure of improvement in the D + Q2 group was higher than that of the D + Q1 group.

Conclusions

Quercetin improved liver function after diabetes mellitus type 1, possibly due to reduced lipid peroxidation, increased antioxidant systems, and inhibiting the apelin/TGF-ꞵ signaling pathway.

Fingolimod alleviates type 2 diabetes associated cognitive decline by regulating autophagy and neuronal apoptosis via AMPK/mTOR pathway

This study aimed to reveal the role of fingolimod (FTY720) in mice with type 2 diabetes-associated cognitive decline and explore its potential neuroprotective mechanism. Mice were divided into five groups: normal control, normal control + FTY720 (1.0 mg/kg/day), type 2 diabetes mellitus, type 2 diabetes mellitus + low-dose FTY720 (0.5 mg/kg/day), and type 2 diabetes mellitus + high-dose FTY720 (1.0 mg/kg/day). Different doses of FTY720 were administered daily for 8 weeks after the induction of type 2 diabetes using a four-week high-fat diet feeding combined with continuous low-dose intraperitoneal injections of streptozotocin. After 8 weeks of treatment, the body weights and fasting blood glucose levels of mice from the five groups were compared. Morris water maze and new object recognition tests were used to evaluate cognitive function. Pathological changes in the hippocampal CA1 region were observed using haematoxylin-eosin and Nissl staining, and the ultrastructure of the hippocampal neurones was assessed using transmission electron microscopy. The expression levels of autophagy- and apoptosis-related proteins, such as LC3, Beclin-1, P62, Bax, and Bcl-2, in the mice hippocampus were detected by western blotting. Simultaneously, AMPK/mTOR signaling pathway proteins were detected to understand the potential mechanism. FTY720 had no significant effect on the body weight or fasting blood glucose levels in mice with type 2 diabetes. However, both FTY720 doses improved the cognitive function and hippocampal damage. In addition, the results suggested that FTY720 dramatically decreased P62 and Bax levels and increased LC3 II/LC3 I ratio, Beclin-1, and Bcl-2 expression in the hippocampus of type 2 diabetic mice. FTY720 also affected the expression of the AMPK/mTOR signaling pathway. Thus, FTY720 improved cognitive function and hippocampal pathological changes in type 2 diabetic mice without affecting fasting blood glucose levels. Our results show that FTY720 may exert neuroprotective effects in vivo by enhancing hippocampal autophagy and inhibiting apoptosis via the AMPK/mTOR signaling pathway.

Maggot extract accelerates skin wound healing of diabetic rats via enhancing STAT3 signaling

BACKGROUND

Diabetic skin wound is a complex problem due to the disruption of normal repairing program and lack of effective remedy. Lucilia sericata larvae (maggot) is a folk method to treat chronic skin wound, while its therapeutic effects on that caused by diabetic remains unknown.

OBJECTIVE

This study aims to investigate the therapeutic effects of maggot extract (M.E.) on diabetic skin wound and its molecular mechanism by establishing the skin wound model of diabetic Sprague Dawley (SD) rats.

METHODS

Diabetic model was established by injecting intraperitoneally streptozotocin in SD rats under specific pathogen-free (SPF) conditions. The rat fasting blood glucose values were ≧16.7 mmol/L 72 hours after intraperitoneal streptozotocin (60mg/kg body weight) injection. The rats were divided into five groups (n = 10/group): normal group: normal SD rats without any treatment, diabetic blank group: the diabetic rats without any treatment, Vaseline group: the diabetic rats dressed with Vaseline, recombinant human epidermal-growth-factor (rhEGF) group: the diabetic rats dressed with a mixture of Vaseline and 200 μg/g rhEGF, M.E. group: the diabetic rats dressed with a mixture of Vaseline and 150 μg/ml maggot extract. The round open wounds (1.0 cm in diameter) down to the muscle fascia were made on both sides of rat dorsa by removing the skin layer (epidermis and dermis) and were daily photographed for calculating their healing rates. Hematoxylin-eosin (HE) and Masson's trichrome staining were performed on skin wound sections to analyze re-epithelialization and granulation tissue formation. Immunohistochemical (IHC), immunofluorescent (IF) stainings and Western blotting were conducted to analyze the statuses of STAT3 signaling.

RESULTS

The average wound healing rates on the 14th day were 91.7% in the normal, 79.6% in M.E., 71% in rhEGF, 55.1% in vaseline and 43.3% in the diabetes blank group. Morphological staining showed more active granulation tissue formation, re-epithelialization and neovascularization in M.E.-group than those in the blank and the vaseline-treated groups. Decreased p-STAT3 nuclear tranlocation and down-regulated Bcl-2, CyclinD1 and vascular endothelial growth factor (VEGF) expression were evidenced in the diabetic rats, which could be improved by rhEGF and especially M.E.

CONCLUSION

Maggot extract would be an alternative and/or adjuvant candidate for the better management of diabetic skin wounds because of its activity in enhancing STAT3 activation.

Discovery and Profiling of New Multimodal Phenylglycinamide Derivatives as Potent Antiseizure and Antinociceptive Drug Candidates

We developed a focused series of original phenyl-glycinamide derivatives which showed potent activity across in vivo mouse seizure models, namely, maximal electroshock (MES) and 6 Hz (using both 32 and 44 mA current intensities) seizure models. Following intraperitoneal (i.p.) administration, compound (R)-32, which was identified as a lead molecule, demonstrated potent protection against all seizure models with ED50 values of 73.9 mg/kg (MES test), 18.8 mg/kg (6 Hz, 32 mA test), and 26.5 mg/kg (6 Hz, 44 mA test). Furthermore, (R)-32 demonstrated efficacy in both the PTZ-induced kindling paradigm and the ivPTZ seizure threshold test. The expression of neurotrophic factors, such as mature brain-derived neurotrophic factor (mBDNF) and nerve growth factor (NGF), in the hippocampus and/or cortex of mice, and the levels of glutamate and GABA were normalized after PTZ-induced kindling by (R)-32. Importantly, besides antiseizure activity, (R)-32 demonstrated potent antinociceptive efficacy in formalin-induced pain, capsaicin-induced pain, as well as oxaliplatin- and streptozotocin-induced peripheral neuropathy in mice (i.p.). No influence on muscular strength and body temperature in mice was observed. Pharmacokinetic studies and in vitro ADME-Tox data (i.e., high metabolic stability in human liver microsomes, a weak influence on CYPs, no hepatotoxicity, satisfactory passive transport, etc.) proved favorable drug-like properties of (R)-32. Thermal stability of (R)-32 shown in thermogravimetry and differential scanning calorimetry gives the opportunity to develop innovative oral solid dosage forms loaded with this compound. The in vitro binding and functional assays indicated its multimodal mechanism of action. (R)-32, beyond TRPV1 antagonism, inhibited calcium and sodium currents at a concentration of 10 μM. Therefore, the data obtained in the current studies justify a more detailed preclinical development of (R)-32 for epilepsy and pain indications.

Mathurameha ameliorates cardiovascular complications in high-fat diet/low-dose streptozotocin-induced type 2 diabetic rats: insights from histological and proteomic analysis

Type 2 diabetes mellitus (T2DM) is a global health concern with increasing prevalence. Mathurameha, a Thai herbal formula, has shown promising glucose-lowering effects and positive impacts on biochemical profiles in diabetic rats. The present study investigated the protective effects of Mathurameha on cardiovascular complications in high-fat diet/streptozotocin (HFD/STZ)-induced type 2 diabetic rats using histological and proteomic analyses. Thirty-five male Sprague-Dawley rats were divided into seven groups: normal diet (ND), ND with aqueous extract (ND + AE450), ND with ethanolic extract (ND + EE200), diabetes (DM), DM with AE (DM + AE450), DM with EE (DM + EE200), and DM with metformin (DM + Met). Mathurameha, especially at 200 mg/kg EE, significantly reduced adipocyte size, cardiac and vascular abnormalities, collagen deposition, and arterial wall thickness in DM rats. Proteomic analysis of rat aortas revealed 30 significantly altered proteins among the ND, DM, and DM + EE200 groups. These altered proteins are involved in various biological processes related to diabetes. Biochemical assays showed that Mathurameha reduced lipid peroxidation (MDA), increased antioxidant levels (GSH), and decreased the expression of inflammatory markers (ICAM1, TNF-α). In conclusion, Mathurameha exhibited significant protective effects against cardiovascular complications in HFD/STZ-induced type 2 diabetic rats through its antioxidant and anti-inflammatory properties.

Liquiritin ameliorates painful diabetic neuropathy in SD rats by inhibiting NLRP3-MMP-9-mediated reversal of aquaporin-4 polarity in the glymphatic system

Background

Despite advancements in diabetes treatment, the management of Painful Diabetic Neuropathy (PDN) remains challenging. Our previous research indicated a significant correlation between the expression and distribution of Aquaporin-4 (AQP4) in the spinal glymphatic system and PDN. However, the potential role and mechanism of liquiritin in PDN treatment remain uncertain.

Methods

This study established a rat model of PDN using a combination of low-dose Streptozotocin (STZ) and a high-fat, high-sugar diet. Rats were treated with liquiritin and MCC950 (an NLRP3 inhibitor). We monitored fasting blood glucose, body weight, and mechanical allodynia periodically. The glymphatic system's clearance function was evaluated using Magnetic Resonance Imaging (MRI), and changes in proteins including NLRP3, MMP-9, and AQP4 were detected through immunofluorescence and Western blot techniques.

Results

The rats with painful diabetic neuropathy (PDN) demonstrated several physiological changes, including heightened mechanical allodynia, compromised clearance function within the spinal glymphatic system, altered distribution of AQP4, increased count of activated astrocytes, elevated expression levels of NLRP3 and MMP-9, and decreased expression of AQP4. However, following treatment with liquiritin and MCC950, these rats exhibited notable improvements.

Conclusion

Liquiritin may promote the restoration of AQP4 polarity by inhibiting NLRP3 and MMP-9, thereby enhancing the clearance functions of the spinal cord glymphatic system in PDN rats, alleviating the progression of PDN.

Polyphenol hydroxytyrosol present olive oil improves skin wound healing of diabetic mice

The imbalance in oxidant production and chronic inflammation are the main mechanisms that lead to the detrimental effects of diabetes on skin wound healing. Thus, administration of antioxidants could improve diabetic wound healing. This study aimed to understand the effects of extra virgin olive oil (EVOO) or hydroxytyrosol (HT) in skin wound healing under diabetic conditions. Skin wounds in streptozotocin-induced diabetic mice were topically treated with HT. Some diabetic animals were fed with a diet rich in EVOO. Wounds were harvested 7 days later. In in vitro assays, fibroblasts and macrophages were treated with high levels of glucose and HT. The EVOO or HT promoted wound closure and collagen deposition in diabetic mouse wounds. The EVOO or HT reduced the number of infiltrated neutrophils, tumour necrosis factor-α, lipid peroxidation, and nuclear factor erythroid 2-related factor 2 in diabetic mouse wounds. The EVOO or HT also increased the number of macrophages with anti-inflammatory phenotype and interleukin-10 in diabetic mouse wounds. In the in vitro assays, HT promoted the fibroblast migration, collagen gel contraction, and switched macrophages to an anti-inflammatory phenotype under high glucose conditions. In conclusion, the diet supplementation with EVOO or topical application of HT promotes skin wound healing under diabetic conditions and can be a possible therapeutic tool for the treatment of those lesions.

Harnessing cellular therapeutics for type 1 diabetes mellitus: progress, challenges, and the road ahead

Type 1 diabetes mellitus (T1DM) is a growing global health concern that affects approximately 8.5 million individuals worldwide. T1DM is characterized by an autoimmune destruction of pancreatic β cells, leading to a disruption in glucose homeostasis. Therapeutic intervention for T1DM requires a complex regimen of glycaemic monitoring and the administration of exogenous insulin to regulate blood glucose levels. Advances in continuous glucose monitoring and algorithm-driven insulin delivery devices have improved the quality of life of patients. Despite this, mimicking islet function and complex physiological feedback remains challenging. Pancreatic islet transplantation represents a potential functional cure for T1DM but is hindered by donor scarcity, variability in harvested cells, aggressive immunosuppressive regimens and suboptimal clinical outcomes. Current research is directed towards generating alternative cell sources, improving transplantation methods, and enhancing cell survival without chronic immunosuppression. This Review maps the progress in cell replacement therapies for T1DM and outlines the remaining challenges and future directions. We explore the state-of-the-art strategies for generating replenishable β cells, cell delivery technologies and local targeted immune modulation. Finally, we highlight relevant animal models and the regulatory aspects for advancing these technologies towards clinical deployment.

Sodium butyrate improves cognitive dysfunction in high-fat diet/ streptozotocin-induced type 2 diabetic mice by ameliorating hippocampal mitochondrial damage through regulating AMPK/PGC-1α pathway

Cognitive dysfunction is an important comorbidity of type 2 diabetes mellitus (T2DM). Sodium butyrate (NaB) is a short-chain fatty acid and has an effect improving T2DM-associated cognitive dysfunction. Using a high-fat diet (HFD)/streptozotocin (STZ)-induced T2DM mouse model, the present study investigated the mechanism involved in the beneficial effect of butyrate on diabetic cognitive dysfunction, with a focus on ameliorating mitochondrial damage through regulating the adenosine monophosphate-activated protein kinase/peroxisome proliferator-activated receptor gamma coactivator 1α (AMPK/PGC-1α) pathway considering the important role of mitochondrial impairments in the occurrence of T2DM-associated cognitive dysfunction. We found, based on reconfirmation of the improvement of NaB on cognitive impairment, that NaB treatment improved damaged synaptic structural plasticity including the decrease in dendritic spine density and downregulation in the expression of postsynaptic density protein 95 and synaptophysin in the hippocampus in the model mice. NaB treatment also ameliorated mitochondrial ultrastructural damage, increased mitochondrial membrane potential and adenosine 5'-triphosphate content, and improved mitochondrial biogenesis and dynamics in the model mice. Furthermore, the expression of phosphorylated AMPK and PGC-1α was upregulated after NaB treatment in the model mice. In particular, the above beneficial effects of NaB were blocked by the inhibition of either AMPK or PGC-1α. In conclusion, NaB treatment improved cognitive impairment and damaged synaptic structural plasticity in the hippocampus by ameliorating damage to mitochondrial morphology and function through regulating the AMPK/PGC-1α pathway in HFD/STZ-induced T2DM mice.

Brain Microvascular Pericyte Pathology Linking Alzheimer's Disease to Diabetes

The brain microvasculature, which delivers oxygen and nutrients and forms a critical barrier protecting the central nervous system via capillaries, is deleteriously affected by both Alzheimer's disease (AD) and type 2 diabetes (T2D). T2D patients have an increased risk of developing AD, suggesting potentially related microvascular pathological mechanisms. Pericytes are an ideal cell type to study for functional links between AD and T2D. These specialized capillary-enwrapping cells regulate capillary density, lumen diameter, and blood flow. Pericytes also maintain endothelial tight junctions to ensure blood-brain barrier integrity, modulation of immune cell extravasation, and clearance of toxins. Changes in these phenomena have been observed in both AD and T2D, implicating "pericyte pathology" as a common feature of AD and T2D. This review examines the mechanisms of AD and T2D from the perspective of the brain microvasculature, highlighting how pericyte pathology contributes to both diseases. Our review identifies voids in understanding how AD and T2D negatively impact the brain microvasculature and suggests future studies to examine the intersections of these diseases.

Impact of apoptosis and oxidative stress on pancreatic beta cell pathophysiology in streptozotocin-induced Type 1 diabetes mellitus

AIMS

Hyperglycemia plays a crucial role in the islet cells, especially pancreatic beta cell death in type 1 diabetes mellitus (T1DM). However, a few research have concentrated on the pathophysiology of apoptosis and oxidative stress in T1DM. The aim of this study was to determine the expression of Caspase 3, Caspase 9, 8-OHdG, Glutathione Reductase, endothelial and inducible nitric oxide synthase in the pancreatic tissue of streptozotocin (STZ)-induced T1DM patients and to compare the cellular mechanisms underlying this metabolic disorder.

METHODS

For this purpose, a total of 20 Wistar albino rats were divided into two groups: Control (C) and Diabetes Mellitus (DM). In the DM group, T1DM was induced by STZ. Rats in the C group were injected intravenously with buffer solution. At the end of the day 20, rats were necropsied and immunohistochemical procedures were applied.

RESULTS

The immunohistochemical examination revealed, strong positive immunoreactions were observed in the islet cells of the DM groups, particularly when all antibody stains were considered. On the other hand, the C groups showed minimal changes. The difference between the C and DM groups in terms of all antibodies was statistically significant (p<0.01).

CONCLUSIONS

In the present study, it was concluded that apoptosis, oxidative stress and NOS expressions were involved in islet cell destruction in pancreatic tissue in STZ-induced T1DM.

Hydrazone-flavonol based oxidovanadium(V) complexes: Synthesis, characterization and antihyperglycemic activity of chloro derivative in vivo

Wet synthesis approach afforded four new heteroleptic mononuclear neutral diamagnetic oxidovanadium(V) complexes, comprising salicylaldehyde-based 2-furoic acid hydrazones and a flavonol coligand of the general composition [VO(fla)(L-ONO)]. The complexes were comprehensively characterized, including chemical analysis, conductometry, infrared, electronic, and mass spectroscopy, as well as 1D 1H and proton-decoupled 13C(1H) NMR spectroscopy, alongside extensive 2D 1H1H COSY, 1H13C HMQC, and 1H13C HMBC NMR analyses. Additionally, the quantum chemical properties of the complexes were studied using Gaussian at the B3LYP, HF, and M062X levels on the 6-31++g(d,p) basis sets. The interaction of these hydrolytically inert vanadium complexes and the BSA was investigated through spectrofluorimetric titration, synchronous fluorimetry, and FRET analysis in a temperature-dependent manner, providing valuable thermodynamic insights into van der Waals interactions and hydrogen bonding. Molecular docking was conducted to gain further understanding of the specific binding sites of the complexes to BSA. Complex 2, featuring a 5-chloro-substituted salicylaldehyde component of the hydrazone, was extensively examined for its biological activity in vivo. The effects of complex administration on biochemical and hematological parameters were evaluated in both healthy and diabetic Wistar rats, revealing antihyperglycemic activity at millimolar concentration. Furthermore, histopathological analysis and bioaccumulation studies of the complex in the brain, kidneys, and livers of healthy and diabetic rats revealed the potential for further development of vanadium(V) hydrazone complexes as antidiabetic and insulin-mimetic agents.

Role of hypoxia-inducible factor 1 in type 1 diabetes

Type 1 diabetes (T1D) is a common autoimmune disease in which dysregulated glucose metabolism is a key feature. T1D is both poorly understood and in need of improved therapeutics. Hypoxia is frequently encountered in multiple tissues in T1D patients including the pancreas and sites of diabetic complications. Hypoxia-inducible factor (HIF)-1, a ubiquitous master regulator of the adaptive response to hypoxia, promotes glucose metabolism through transcriptional and non-transcriptional mechanisms and alters disease progression in multiple preclinical T1D models. However, how HIF-1 activation in β-cells of the pancreas and immune cells (two key cell types in T1D) ultimately affects disease progression remains controversial. We discuss recent advances in our understanding of the role of hypoxia/HIF-1-induced glycolysis in T1D and explore the possible use of drugs targeting this pathway as potential new therapeutics.

The flavonoid fisetin reduces multiple physiological risk factors for dementia

Dementia is a growing problem around the globe as the world's population continues to age. Multiple studies have identified potentially modifiable risk factors for the development of dementia suggesting that addressing some or all of these risk factors might have a significant impact on the aging population worldwide. However, this is not always as straightforward as it seems since many of these risk factors are currently treated with drugs specific to the risk factor. Moreover, since people can have multiple risk factors, addressing each of them individually could be highly problematic as it would likely lead to negative outcomes associated with polypharmacy and, in the long term, could do significant harm. A potential alternative is to identify compounds that have shown efficacy against a number of these different risk factors. As discussed in this review, there is strong evidence that the flavonol fisetin is one such compound. In animal studies it has shown efficacy against many of the risk factors that have been associated with an increased risk of developing dementia and also exhibits direct neuroprotective effects. Thus, further human research on fisetin in the context of dementia risk factors is clearly warranted.

eNAMPT is a novel therapeutic target for mitigation of coronary microvascular disease in type 2 diabetes

AIMS/HYPOTHESIS

Individuals with diabetes are at high risk of cardiovascular complications, which significantly increase morbidity/mortality. Coronary microvascular disease (CMD) is recognised as a critical contributor to the increased cardiac mortality observed in people with diabetes. Therefore, there is an urgent need for treatments that are specific to CMD. eNAMPT (extracellular nicotinamide phosphoribosyltransferase) is a damage-associated molecular pattern and TLR4 ligand, whose plasma levels are elevated in people with diabetes. This study was thus designed to investigate the pathogenic role of intracellular nicotinamide phosphoribosyltransferase (iNAMPT) and eNAMPT in promoting the development of CMD in a preclinical murine model of type 2 diabetes.

METHODS

An inducible type 2 diabetic mouse model was generated by a single injection of low-dose streptozocin (75 mg/kg, i.p.) combined with a high-fat diet for 16 weeks. The in vivo effects of i/eNAMPT inhibition on cardiac endothelial cell (CEC) function were evaluated by using Nampt+/- heterozygous mice, chronic administration of eNAMPT-neutralising monoclonal antibody (mAb) or use of an NAMPT enzymatic inhibitor (FK866).

RESULTS

As expected, diabetic wild-type mice exhibited significantly lower coronary flow velocity reserve (CFVR), a determinant of coronary microvascular function, compared with control wild-type mice. eNAMPT plasma levels or expression in CECs were significantly greater in diabetic mice than in control mice. Furthermore, in comparison with diabetic wild-type mice, diabetic Nampt+/- heterozygous mice showed markedly improved CFVR, accompanied by increased left ventricular capillary density and augmented endothelium-dependent relaxation (EDR) in the coronary artery. NAMPT inhibition by FK866 or an eNAMPT-neutralising mAb significantly increased CFVR in diabetic mice. Furthermore, administration of the eNAMPT mAb upregulated expression of angiogenesis- and EDR-related genes in CECs from diabetic mice. Treatment with either eNAMPT or NAD+ significantly decreased CEC migration and reduced EDR in coronary arteries, partly linked to increased production of mitochondrial reactive oxygen species.

CONCLUSIONS/INTERPRETATION

These data indicate that increased i/eNAMPT expression contributes to the development of diabetic coronary microvascular dysfunction, and provide compelling support for eNAMPT inhibition as a novel and effective therapeutic strategy for CMD in diabetes.

Converting Short-Acting Insulin into Thermo-Stable Longer-Acting Insulin Using Multi-Layer Detachable Microneedles

The detachable dissolving microneedles (DDMNs) feature an array of needles capable of being separated from the base sheet during administration. Here they were fabricated to address delivery efficiency and storage stability of insulin. The constructed insulin-DDMN is multi-layered, with 1) a hard tip cover layer; 2) a layer of regular short-acting insulin (RI) mixed with hyaluronic acid (HA) and sorbitol (Sor) which occupies the taper tip region of the needles; 3) a barrier layer situated above the RI layer; and 4) a fast-dissolving layer connecting the barrier layer to the base sheet. RI entrapped in DDMNs exhibited enhanced thermal stability; it could be stored at 40 °C for 35 days without losing significant biological activity. Differential scanning calorimetric analysis revealed that the HA-Sor matrix could improve the denaturation temperature of the RI from lower than room temperature to 186 °C. Tests in ex vivo porcine skin demonstrated RI delivery efficiency of 91±1.59 %. Experiments with diabetic rats revealed sustained release of RI, i.e., when compared to subcutaneous injection with the same RI dose, RI-DDMNs produced slower absorption of insulin into blood circulation, delayed onset of hypoglycemic effect, longer serum insulin half-life, and longer hypoglycemic duration.

Exercise training and spexin ameliorate thyroid changes in obese type 2 diabetic rats: the possible interlaying mechanisms

Thyroid dysfunction and diabetes mellitus are prevalent endocrine disorders that often coexist and influence each other. The role of spexin (SPX) in diabetes and obesity is well documented, but its connection to thyroid function is less understood. This study investigates the influence of exercise (EX) and SPX on thyroid hypofunction in obese type 2 diabetic rats. Rats were divided into normal control, obese diabetic sedentary, obese diabetic EX, and obese diabetic SPX groups, with subdivisions for M871 and HT-2157 treatment in the latter two groups. High-fat diet together with streptozotocin (STZ) injection induced obesity and diabetes. The EX group underwent swimming, and the SPX group received SPX injections for 8 wk. Results showed significant improvements in thyroid function and metabolic, oxidative, and inflammatory states with EX and SPX treatment. The study also explored the involvement of galanin receptor isoforms (GALR)2/3 in SPX effects on thyroid function. Blocking GALR2/3 receptors partially attenuated the beneficial effects, indicating their interaction. These findings underscore the importance of EX and SPX in modulating thyroid function in obesity and diabetes. Comprehending this interplay could enable the development of new treatment approaches for thyroid disorders associated with obese type 2 diabetes. Additional research is necessary to clarify the exact mechanisms connecting SPX, EX activity, and thyroid function.NEW & NOTEWORTHY This study proves, for the first time, the beneficial effects of SPX on thyroid dysfunction in obese diabetic rats and suggests that SPX mediates the EX effect on thyroid gland and exerts its effect mainly via GALR2.

5-aminolevulinic acid photodynamic therapy for chronic wound infection in rats with diabetes

Recent research indicated that ulcers and peripheral vascular disease resulting from drug-resistant bacterial infections are the main causes of delayed healing in chronic diabetic wounds. 5-Aminolevulinic acid (ALA) is a second-generation endogenous photosensitizer. The therapeutic effect and mechanism of ALA-mediated photodynamic therapy (ALA-PDT) on methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds in diabetic rats were investigated in this study. The results revealed the promising antibacterial effects of ALA-PDT MRSA in vitro, with a minimum inhibitory concentration and minimum bactericidal concentration of 250 and 500 μM, respectively. ALA-PDT also changed the permeability and structural integrity of bacterial cell membranes by producing reactive oxygen species. Meanwhile, ALA-PDT accelerated wound healing in MRSA-infected diabetic rats, with 5 % ALA-PDT achieving complete sterilization in 14 days and wound closure in 21 days. Treatment with 5 % ALA-PDT additionally improved the histopathological appearance of skin tissue, as well as fibrosis, inflammatory cytokine release, and angiogenesis-related protein expression. These findings indicated that ALA-PDT significantly promoted the healing of MRSA-infected wounds in diabetic rats by eliminating bacteria, inhibiting inflammation, generating granulation tissues, promoting neovascularization, and restoring damaged nerves. In addition, the healing mechanism was related to the activation of inflammatory and angiogenesis pathways through the regulation of tumor necrosis factor-alpha and interleukin-6 expression and upregulation of CD206, CD31, and VEGF. These findings underscored the potential role of ALA-PDT in promoting the healing of chronic diabetic wounds.

Harnessing the therapeutic potential of bone marrow-derived stem cells for sciatic nerve regeneration in diabetic neuropathy

Diabetic peripheral neuropathy (DPN) is a common complication of diabetes that affects the angiogenesis and myelination of peripheral nerves. In this study, we investigated the potential of mesenchymal stem cells (MSCs) transplantation to improve DPN by enhancing angiogenesis and remyelination in the sciatic nerve of streptozotocin (STZ)-induced diabetic female rats. The purpose of this study was to evaluate the therapeutic potential of mesenchymal stem cells as a possiblity for clinical intervention to alleviate the symptoms of diabetic peripheral neuropathy. We examined whether transplanted mesenchymal stem cells can produce new and restored angiogenesis, as well as promoting myelination. Overall, our findings suggest that MSCs transplantation has neuroprotective effects. This is particularly the case for Schwann cells. Transplantation may stimulate angiogenesis as well as remyelination of the sciatic nerve in experimentally-induced diabetic peripheral neuropathy. Behavioral assays, histological analysis, and molecular techniques were used to assess the effects of MSCs transplantation. Our results demonstrate that in diabetic rats signs of neuropathy were reversed following a single administration of bone marrow-derived MSCs. Morphological and morphometric analysis of the sciatic nerve revealed that diabetic rats displayed structural alterations that were attenuated with MSCs transplantation.Immunostaining analysis showed increased expression of S100 and VEGF in the sciatic nerve following MSCs transplantation. Western blotting analysis also revealed elevated levels of VEGF and CD31 in rats treated with MSCs compared to diabetic rats.

Glucose-Operated Widget (GLOW) for Closed-Loop Optogenetic Glycemic Control

Closed-loop control systems for precise control of therapeutic gene expression are promising candidates for personalized treatment of chronic ailments such as diabetes. Pancreatic iβ-cells are engineered with blue-light-inducible melanopsin to drive rapid insulin release by vesicular secretion from intracellular stores. In this work, a glucose-operated widget (GLOW) is designed as a component of a closed-loop control system for diabetes treatment by employing a probe that emits blue fluorescence in a glucose-concentration-dependent manner as a real-time glucose sensor to precisely control insulin release from these iβ-cells. As proof-of-concept of the complete control system, the probe is encapsulated together with iβ-cells in alginate-poly-(L-lysine) hydrogel-microbeads(400 µm in diameter and containing about 500 cells) called GLOWiβ (GLOW with iβ-cells), are subcutaneously implanted into type-1-diabetic (T1D) mice. Illumination by UV-A light at 390 nm results in glucose-concentration-dependent blue-light emission from the probe at 445 nm that in turn induces glucose-concentration-dependent insulin release from the iβ-cells in a fully reversible manner. Activation of the injected GLOWiβ at 390 nm for 15 min effectively restores normoglycemia within 60-120 min in a closed-loop manner in these diabetic mice. The system is robust, as normoglycemia is well maintained by daily activation for at least 7 days.

Antioxidant Effect in Diabetic Peripheral Neuropathy in Rat Model: A Systematic Review

Oxidative stress is a contributing factor that leads to the vascular complications of diabetes mellitus. Diabetic peripheral neuropathy (DPN) is one of the microvascular complications with rising concern as the disease progresses despite strict glucose control and monitoring. Thus, there is an ongoing need for an early intervention that is effective in halting or slowing the progression of DPN where antioxidants have been proposed as potential therapeutic agents. This systematic review aims to evaluate the existing evidence on the antioxidant effect in DPN and provide insight on the role of antioxidants in the progression of DPN in a rat model. A comprehensive literature search was conducted on Web of Science, EBSCOhost, and Scopus to identify the effects and role of antioxidants in DPN. Data extraction was performed and SYRCLE's risk of bias (RoB) tool was used for risk assessment. This systematic review was written following the PRISMA 2020 statements. From the literature search, 1268 articles were screened, and a total of 101 full-text articles were further screened before 33 were analyzed. These findings collectively suggest that antioxidants can play a crucial role in managing and potentially reversing the effects of diabetic neuropathy by targeting oxidative stress and improving nerve function.

Daphnetin modulates GLP-1R to alleviate cognitive dysfunction in diabetes: implications for inflammation and oxidative stress

Daphnetin exerts certain pharmacological function on a variety of diseases, but its role in diabetic cognitive dysfunction has not been elucidated. In this study, we carried a series of pharmacological studies of GLP-1R with daphnetin. In rats and PC12 cells, we found that daphnetin could alleviate diabetic cognitive dysfunction and increase the expression level of GLP-1R. Additionally, the anti-diabetic cognitive dysfunction effect of DAP was accompanied by the inhibition of inflammation and oxidative stress. Further in-depth studies demonstrated that the inhibition GLP-1R enhanced the protective effect of daphnetin, whilst, the overexpression of GLP-1R weakened the protective effect of daphnetin. These results indicated that daphnetin protects diabetes cognitive dysfunction by regulating GLP-1R-mediated inflammation and oxidative stress, act as a GLP-1R agonist. The study further demonstrated that daphnetin has great value in preventing cognitive dysfunction in type 2 diabetes, and GLP-1R is a key potential target for the treatment of related diseases.

Hyperglycemia in a NOD Mice Model of Type-I Diabetes Aggravates Collagenase-Induced Intracerebral Hemorrhagic Injury

BACKGROUND

Intracerebral hemorrhage (ICH) is a severe type of stroke with high mortality. Persistent hyperglycemia following ICH is linked to deteriorated neurological functions and death. However, the exacerbating effect of hyperglycemia on ICH injury at the molecular level is still unclear. Therefore, this study explores the impact of diabetes on ICH injury using a non-obese diabetic (NOD) mouse model of type I diabetes mellitus.

METHODS

NOD and non-diabetic (non-obese resistant) mice subjected to ICH by intrastriatal injection of collagenase were sacrificed three days following the ICH. Brains were collected for hematoma volume measurement and immunohistochemistry. Neurobehavioral assays were conducted 24 h before ICH and then repeated at 24, 48 and 72 h following ICH.

RESULTS

NOD mice showed increased hematoma volume and impairment in neurological function, as revealed by rotarod and grip strength analyses. Immunohistochemical staining showed reduced glial cell activation, as indicated by decreased GFAP and Iba1 staining. Furthermore, the expression of oxidative/nitrosative stress markers represented by 3-nitrotyrosine and inducible nitric oxide synthase was reduced in the diabetic group.

CONCLUSIONS

Overall, our findings support the notion that hyperglycemia exacerbates ICH injury and worsens neurological function and that the mechanism of injury varies depending on the type of diabetes model used.

Therapeutic Effects of Nigella sativa Oil and Whole Seeds on STZ-Induced Diabetic Rats: A Biochemical and Immunohistochemical Study

Background

Type II diabetes mellitus (DM) is an increasing health problem that has negative impacts on patients and healthcare systems, worldwide. The development of new therapies with better efficacy, fewer side effects, and lower prices are urgently needed to treat this disease.

Aim

To evaluate and compare the therapeutic effects of Nigella sativa (N. sativa) seed and oil on the biochemical parameters and regeneration of pancreatic islets (or islets of Langerhans) of streptozotocin (STZ)-induced diabetic rats.

Materials and Methods

The diabetic rat model was prepared by administering a single dose of STZ (35 mg/kg body weight). The whole seed or the oil of N. sativa was administered to the diabetic and control groups for a period of 28 days, but not to the negative and STZ controls. Serum blood glucose, liver enzymes, lipid profile, and renal function tests (uric acid, albumin, total protein, urea, and creatinine) were measured in all groups. After the rats were euthanized, their pancreases were extracted, and then sectioned and fixed on slides in preparation before staining with H&E stain and immunohistochemical study.

Results

Treatment of STZ-diabetic rats with N. sativa seeds or oil significantly improved their serum glucose levels, lipid profiles, and liver and renal functions as well as preserved the integrity of pancreatic β cells.

Conclusion

N. sativa seeds and oil demonstrate significant therapeutic improvement effects on DM and its related complications including effective protection of islets of Langerhans. The therapeutic benefits of N. sativa seeds and oil on DM and its related complications are comparable.

Seed Disinfection Treatments Minimized Microbial Load and Enhanced Nutritional Properties of Fenugreek Sprouts Which Alleviated Diabetes-Negative Disorders in Diabetic Rats

Sprouts are an attractive food product that contains high amounts of nutritional substances and has pro-health features. Sprout consumption has strongly increased despite its potential risk to health due to its microbial load. Both the safety and shelf life of sprouts may be negatively affected by a high microbial load. To reduce the microbial contamination in sprouts before consumption, the initial microbial load on the seeds needs to be controlled. Many herbal sprouts have been recommended for diabetes, and fenugreek is one of these sprouts. Thus, the current experiment aimed at disinfecting fenugreek seeds using microwave (5, 10, and 20 s) and hot water (30, 45, and 60 s) treatments for different durations. The best-disinfected sprouts with the highest nutritional properties were used to evaluate their influence on streptozocin-induced diabetic rats in comparison with fenugreek seed feeding. Microwave treatments showed the highest sprout length, fresh weight, total free amino acids, antioxidants, reducing sugars, and total phenols. Additionally, microwave seed treatments showed the lowest bacteria and mold counts on sprouts produced relative to hot water treatments, and the best seed treatment was a microwave for 20 s, which gave the best values in this respect. Feeding diabetic rats with different fenugreek seeds or sprout rates (0, 5, 7.5, and 10% w/w) improved body weight, restricted the growth of glucose levels, lowered total cholesterol and triglycerides, and improved HDL compared with the positive control group, and fenugreek sprouts at higher rates showed the maximum improvements in blood glucose, total cholesterol, and triglycerides. Treating fenugreek seed with microwave radiation for 20 s to disinfect the seeds before sprouting is recommended for lowering the microbial load with optimum nutritional and antioxidant activity, and feeding diabetic rats with these sprouts at the rate of 7.5 and 10% had promising effects on hyperglycemia and associated disorders.

Molecular mechanisms of enteric neuropathies in high-fat diet feeding and diabetes

BACKGROUND

Obesity and diabetes are associated with altered gastrointestinal function and with the development of abdominal pain, nausea, diarrhea, and constipation among other symptoms. The enteric nervous system (ENS) regulates gastrointestinal motility. Enteric neuropathies defined as damage or loss of enteric neurons can lead to motility disorders.

PURPOSE

Here, we review the molecular mechanisms that drive enteric neurodegeneration in diabetes and obesity, including signaling pathways leading to neuronal cell death, oxidative stress, and microbiota alteration. We also highlight potential approaches to treat enteric neuropathies including antioxidant therapy to prevent oxidative stress-induced damage and the use of stem cells.

Preclinical Evaluation of Sigma 1 Receptor Antagonists as a Novel Treatment for Painful Diabetic Neuropathy

The global prevalence of diabetes is steadily rising, with an estimated 537 million adults affected by diabetes in 2021, projected to reach 783 million by 2045. A severe consequence of diabetes is the development of painful diabetic neuropathy (PDN), afflicting approximately one in every three diabetic patients and significantly compromising their quality of life. Current pharmacotherapies for PDN provide inadequate pain relief for many patients, underscoring the need for novel treatments that are both safe and effective. The Sigma 1 Receptor (S1R) is a ligand-operated chaperone protein that resides at the mitochondria-associated membrane of the endoplasmic reticulum. The S1R has been shown to play crucial roles in regulating cellular processes implicated in pain modulation. This study explores the potential of PW507, a novel S1R antagonist, as a therapeutic candidate for PDN. PW507 exhibited promising in vitro and in vivo properties in terms of ADME, toxicity, pharmacokinetics, and safety. In preclinical rat models of Streptozotocin-induced diabetic neuropathy, PW507 demonstrated significant efficacy in alleviating mechanical allodynia and thermal hyperalgesia following both acute and chronic (2-week) administration, without inducing tolerance and visual evidence of toxicity. To the best of our knowledge, this is the first report to evaluate an S1R antagonist in STZ-induced diabetic rats following both acute and 2-week chronic administration, offering compelling preclinical evidence for the potential use of PW507 as a promising therapeutic option for PDN.

A Novel Immunodeficient Hyperglycemic Mouse Carrying the Ins1 Akita Mutation for Xenogeneic Islet Cell Transplantation

BACKGROUND

For patients who have difficulty controlling blood glucose even with insulin administration, xenogeneic islet cells, including human stem cell-derived pancreatic islets (hSC-islet) and porcine islets, have garnered attention as potential solutions to challenges associated with donor shortages. For the development of diabetes treatment modalities that use cell transplantation therapy, it is essential to evaluate the efficacy and safety of transplanted cells using experimental animals over the long term.

METHODS

We developed permanent diabetic immune-deficient mice by introducing the Akita (C96Y) mutation into the rodent-specific Insulin1 gene of NOD/Shi-scid IL2rγcnull (NOG) mice (Ins1C96Y/C96Y NOG). Their body weight, nonfasting blood glucose, and survival were measured from 4 wk of age. Insulin sensitivity was assessed via tolerance tests. To elucidate the utility of these mice in xenotransplantation experiments, we transplanted hSC-islet cells or porcine islets under the kidney capsules of these mice.

RESULTS

All male and female homozygous mice exhibited persistent severe hyperglycemia associated with β-cell depletion as early as 4 wk of age and exhibited normal insulin sensitivity. These mice could be stably engrafted with hSC-islets, and the mice that received porcine islet grafts promptly exhibited lowered blood glucose levels, maintaining blood glucose levels below the normal glucose range for at least 52 wk posttransplantation.

CONCLUSIONS

The Ins1C96Y/C96Y NOG mouse model provides an effective platform to assess both the efficacy and safety of long-term xenograft engraftment without the interference of their immune responses. This study is expected to contribute essential basic information for the clinical application of islet cell transplantation.

Investigating the Effects of AL049796.1 Silencing in Inhibiting High Glucose-Induced Colorectal Cancer Progression

Patients with colorectal cancer (CRC) and diabetes share many risk factors. Despite a strong association between diabetes and CRC being widely studied and confirmed, further genetic research is needed. This study found higher AL049796.1 and TEA domain transcription factor 1 (TEAD1) levels (both mRNA and protein) in CRC tissues of diabetic patients compared with nondiabetics, but no significant difference in miR-200b-3p levels. A positive correlation between AL049796.1 and TEAD1 protein existed regardless of diabetes status, whereas miR-200b-3p was only negatively correlated with TEAD1 protein in nondiabetic CRC tissues. In vitro experiments have shown that high glucose (HG) treatment increased AL049796.1 in CRC cells, and AL049796.1 silencing reduced HG-induced proliferation, migration and invasion, as well as connective tissue growth factor, cysteine-rich angiogenic inducer 61, and epidermal growth factor receptor protein expression. Mechanistic investigations indicated that AL049796.1 could mitigate suppression of miR-200b-3p on TEAD1 posttranscriptionally by acting as a competitive binder. In vivo, subcutaneous CRC tumors in streptozotocin (STZ)-induced mice grew significantly faster; AL049796.1 silencing did not affect the growth of subcutaneous CRC tumors but significantly reduced that of STZ-induced mice. Our study suggests that AL049796.1 independently contributes to the risk of CRC in diabetic patients, highlighting its potential as both a therapeutic target and a novel biomarker for CRC among individuals with diabetes.

A CEBPB/miR-32-5p/GATA6 axis promotes vascular calcification in type 2 diabetes

Vascular calcification in diabetes patients is a major independent risk factor for developing diabetic cardiovascular complications. However, the mechanisms by which diabetes leads to vascular calcification are complex and not yet fully understood. Our previous study revealed that miR-32-5p is a potential new diagnostic marker for coronary artery calcification. In this study, we found that miR-32-5p levels were significantly greater in the plasma of type 2 diabetes patients with coronary artery calcification and were positively correlated with the coronary artery calcification score. In type 2 diabetic mice, miR-32-5p levels were also elevated in the aorta, and knockout of miR-32-5p inhibited the osteogenic differentiation of vascular smooth muscle cells in vivo. Furthermore, overexpression of miR-32-5p promoted vascular smooth muscle cell calcification, while antagonism of miR-32-5p inhibited vascular smooth muscle cell calcification under high-glucose conditions. GATA binding protein 6 (GATA6) was identified as the key target gene through which miR-32-5p promotes vascular smooth muscle cell calcification. Overexpression of GATA6 antagonized the effects of miR-32-5p on vascular calcification. Additionally, high glucose levels were shown to induce the upregulation of miR-32-5p by activating CCAAT/enhancer binding protein beta (CEBPB). These results suggest that miR-32-5p is an important procalcification factor in vascular calcification associated with type 2 diabetes and identify the CEBPB/miR-32-5p/GATA6 axis as a potential biomarker and therapeutic target for preventing and treating vascular calcification in type 2 diabetes.