AnnoSpat annotates cell types and quantifies cellular arrangements from spatial proteomics.

Cellular composition and anatomical organization influence normal and aberrant organ functions. Emerging spatial single-cell proteomic assays such as Image Mass Cytometry (IMC) and Co-Detection by Indexing (CODEX) have facilitated the study of cellular composition and organization by enabling high-throughput measurement of cells and their localization directly in intact tissues. However, annotation of cell types and quantification of their relative localization in tissues remain challenging. To address these unmet needs for atlas-scale datasets like Human Pancreas Analysis Program (HPAP), we develop AnnoSpat (Annotator and Spatial Pattern Finder) that uses neural network and point process algorithms to automatically identify cell types and quantify cell-cell proximity relationships. Our study of data from IMC and CODEX shows the higher performance of AnnoSpat in rapid and accurate annotation of cell types compared to alternative approaches. Moreover, the application of AnnoSpat to type 1 diabetic, non-diabetic autoantibody-positive, and non-diabetic organ donor cohorts recapitulates known islet pathobiology and shows differential dynamics of pancreatic polypeptide (PP) cell abundance and CD8+ T cells infiltration in islets during type 1 diabetes progression.

Spontaneous Akt2 deficiency in a colony of NOD mice exhibiting early diabetes.

Diabetes constitutes a major public health problem, with dramatic consequences for patients. Both genetic and environmental factors were shown to contribute to the different forms of the disease. The monogenic forms, found both in humans and in animal models, specially help to decipher the role of key genes in the physiopathology of the disease. Here, we describe the phenotype of early diabetes in a colony of NOD mice, with spontaneous invalidation of Akt2, that we called HYP. The HYP mice were characterised by a strong and chronic hyperglycaemia, beginning around the age of one month, especially in male mice. The phenotype was not the consequence of the acceleration of the autoimmune response, inherent to the NOD background. Interestingly, in HYP mice, we observed hyperinsulinemia before hyperglycaemia occurred. We did not find any difference in the pancreas' architecture of the NOD and HYP mice (islets' size and staining for insulin and glucagon) but we detected a lower insulin content in the pancreas of HYP mice compared to NOD mice. These results give new insights about the role played by Akt2 in glucose homeostasis and argue for the ß cell failure being the primary event in the course of diabetes.

Bone remodeling and responsiveness to mechanical stimuli in individuals with type 1 diabetes mellitus.

Type 1 diabetes mellitus (T1DM) has been linked to increased osteocyte apoptosis, local accumulation of mineralized lacunar spaces, and microdamage suggesting an impairment of the mechanoregulation network in affected individuals. Diabetic neuropathy might exacerbate this dysfunction through direct effects on bone turnover, and indirect effects on balance, muscle strength, and gait. However, the in vivo effects of impaired bone mechanoregulation on bone remodeling in humans remain underexplored. This longitudinal cohort study assessed consenting participants with T1DM and varying degree of distal symmetric sensorimotor polyneuropathy (T1DM, n = 20, median age 46.5 yr, eight female) and controls (CTRL; n = 9, median age 59.0 yr, four female) at baseline and 4-yr follow-up. Nerve conduction in participants with T1DM was tested using DPNCheck and bone remodeling was quantified with longitudinal high-resolution peripheral quantitative-computed tomography (HR-pQCT, 82 µm) at the standard distal sites. Local trabecular bone formation (Tb.F) and resorption (Tb.R) sites were captured by implementing 3D rigid image registration of HR-pQCT images, and the mechanical environment across the bone microarchitecture at these sites was simulated using micro-finite element analysis. We calculated odds ratios to determine the likelihood of bone formation (ORF) and resorption (ORR) with increasing/decreasing strain in percent as markers for mechanoregulation. At the distal radius, Tb.F was 47% lower and Tb.R was 59% lower in T1DM participants compared with CTRL (P < .05). Tb.F correlated positively with nerve conduction amplitude (R = 0.69, P < .05) in participants with T1DM and negatively with glycated hemoglobin (HbA1c) (R = -0.45, P < .05). Additionally, ORF was 34% lower and ORR was 18% lower in T1DM compared with CTRL (P < .05). Our findings represent in vivo evidence suggesting that bone remodeling in individuals with T1DM is in a state of low responsiveness to mechanical stimuli, resulting in impaired bone formation and resorption rates; these correlate to the degree of neuropathy and level of diabetes control.

In a healthy adult, the body's skeleton self-repairs­or remodels­itself to maintain its strength. At the microscopic level, this process is orchestrated by cells, called osteocytes, which can sense and respond to local mechanical forces. Recent studies have suggested that type 1 diabetes mellitus (T1DM), a metabolic bone disease, may negatively impact this mechanically regulated process and reduce bone strength. To investigate this further, we utilized novel methods to monitor local changes in bone microstructure over time using high­resolution peripheral quantitative­computed tomography, allowing us to study the results of cellular behavior on bone remodeling in participants over time. Our study found that bone formation was 47% lower and bone resorption was 59% lower in participants with T1DM compared with controls (CTRL). Bone formation correlated positively with peripheral nerve function and negatively with glycaemic control in participants with T1DM. Furthermore, the links between mechanical forces acting on bone remodeling were 34% weaker for formation and 18% weaker for resorption compared with CTRL. Our findings show that bone remodeling in people with T1DM is in a state of low responsiveness to mechanical stimuli, resulting in impaired bone formation and resorption rates, and ultimately, impaired self-repair.

Diabetes as a Pancreatic Microvascular Disease-A Pericytic Perspective.

Diabetes is not only an endocrine but also a vascular disease. Vascular defects are usually seen as consequence of diabetes. However, at the level of the pancreatic islet, vascular alterations have been described before symptom onset. Importantly, the cellular and molecular mechanisms underlying these early vascular defects have not been identified, neither how these could impact the function of islet endocrine cells. In this review, we will discuss the possibility that dysfunction of the mural cells of the microvasculature-known as pericytes-underlies vascular defects observed in islets in pre-symptomatic stages. Pericytes are crucial for vascular homeostasis throughout the body, but their physiological and pathophysiological functions in islets have only recently started to be explored. A previous study had already raised interest in the "microvascular" approach to this disease. With our increased understanding of the crucial role of the islet microvasculature for glucose homeostasis, here we will revisit the vascular aspects of islet function and how their deregulation could contribute to diabetes pathogenesis, focusing in particular on type 1 diabetes (T1D).

Effects of Diabetes Mellitus on Corneal Immune Cell Activation and the Development of Keratopathy.

Diabetes mellitus (DM) is one of the most prevalent diseases globally, and its prevalence is rapidly increasing. Most patients with a long-term history of DM present with some degree of keratopathy (DK). Despite its high incidence, the underlying inflammatory mechanism of DK has not been elucidated yet. For further insights into the underlying immunopathologic processes, we utilized streptozotocin-induced mice to model type 1 DM (T1D) and B6.Cg-Lepob/J mice to model type 2 DM (T2D). We evaluated the animals for the development of clinical manifestations of DK. Four weeks post-induction, the total frequencies of corneal CD45+CD11b+Ly-6G- myeloid cells, with enhanced gene and protein expression levels for the proinflammatory cytokines TNF-α and IL-1ß, were higher in both T1D and T2D animals. Additionally, the frequencies of myeloid cells/mm2 in the sub-basal neural plexus (SBNP) were significantly higher in T1D and T2D compared to non-diabetic mice. DK clinical manifestations were observed four weeks post-induction, including significantly lower tear production, corneal sensitivity, and epitheliopathy. Nerve density in the SBNP and intraepithelial terminal endings per 40x field were lower in both models compared to the normal controls. The findings of this study indicate that DM alters the immune quiescent state of the cornea during disease onset, which may be associated with the progressive development of the clinical manifestations of DK.

Apigenin ameliorates genitourinary dysfunction in a type 1 diabetic rat model via Drp1 modulation.

The present study aimed to explore the potential ameliorative effect of apigenin (APG) against diabetes-associated genitourinary complications in rats. A diabetic rat model was induced by the intraperitoneal injection of streptozotocin (STZ). All experimental animals were treated with vehicle or vehicle plus APG at a dose of 0.78 mg/kg/day for 10 days, either once diabetes was confirmed or at the end of the 3rd week after confirmation of diabetes. Rats were sacrificed at the end of the fifth week. In addition to the histological assessment, an analysis of kidney function tests and serum testosterone was performed to assess diabetic genitourinary complications. Gene expression of the mitochondrial fission protein, dynamin related protein 1 (Drp1), was measured in renal and testicular tissues using qRT PCR. APG can increase body weight, reduce blood glucose levels, and improve renal and testicular functions in diabetic rats. APG decreased Drp1 overexpression in diabetic animals' kidneys and testes. In summary, our current work discloses that APG attenuates diabetic genitourinary lesions in rats via suppressing Drp1 overexpression.

Poorly controlled type 1 diabetes mellitus seriously impairs female reproduction via immune and metabolic disorders.

RESEARCH QUESTION: Does type 1 diabetes mellitus (T1DM) affect reproductive health of female patients? What is the potential mechanism of reproductive dysfunction in female patients caused by T1DM? DESIGN: Preliminary assessment of serum levels of female hormones in women with or without T1DM. Then histological and immunological examinations were carried out on the pancreas, ovaries and uteri at different stages in non-obese diabetic (NOD) and Institute of Cancer Research (ICR) mice, as well as assessment of their fertility. A protein array was carried out to detect the changes in serum inflammatory cytokines. Furthermore, RNA-sequencing was used to identify the key abnormal genes/pathways in ovarian and uterine tissues of female NOD mice, which were further verified at the protein level. RESULTS: Testosterone levels were significantly increased (P = 0.0036) in female mice with T1DM. Increasing age in female NOD mice was accompanied by obvious lymphocyte infiltration in the pancreatic islets. Moreover, the levels of serum inflammatory factors in NOD mice were sharply increased with increasing age. The fertility of female NOD mice declined markedly, and most were capable of conceiving only once. Furthermore, ovarian and uterine morphology and function were severely impaired in NOD female mice. Additionally, ovarian and uterine tissues revealed that the differentially expressed genes were primarily enriched in metabolism, cytokine-receptor interactions and chemokine signalling pathways. CONCLUSION: T1DM exerts a substantial impairment on female reproductive health, leading to diminished fertility, potentially associated with immune disorders and alterations in energy metabolism.

Predictive biomarkers of rapidly developing insulin deficiency in children with type 1 diabetes.

INTRODUCTION: The rate of progression to complete insulin deficiency varies greatly in type 1 diabetes. This constitutes a challenge, especially when randomizing patients in intervention trials aiming to preserve beta cell function. This study aimed to identify biomarkers predictive of either a rapid or slow disease progression in children with new-onset type 1 diabetes. RESEARCH DESIGN AND METHODS: A retrospective, longitudinal cohort study of children (<18 years) with type 1 diabetes (N=46) was included at diagnosis and followed until complete insulinopenia (C-peptide <0.03 nmol/L). Children were grouped into rapid progressors (n=20, loss within 30 months) and slow progressors (n=26). A sex-matched control group of healthy children (N=45) of similar age was included for comparison. Multiple biomarkers were assessed by proximity extension assay (PEA) at baseline and follow-up. RESULTS: At baseline, rapid progressors had lower C-peptide and higher autoantibody levels than slow. Three biomarkers were higher in the rapid group: carbonic anhydrase 9, corticosteroid 11-beta-dehydrogenase isozyme 1, and tumor necrosis factor receptor superfamily member 21. In a linear mixed model, 25 proteins changed over time, irrespective of group. One protein, a coxsackievirus B-adenovirus receptor (CAR) increased over time in rapid progressors. Eighty-one proteins differed between type 1 diabetes and healthy controls. Principal component analysis could not distinguish between rapid, slow, and healthy controls. CONCLUSIONS: Despite differences in individual proteins, the combination of multiple biomarkers analyzed by PEA could not distinguish the rate of progression in children with new-onset type 1 diabetes. Only one marker was altered significantly when considering both time and group effects, namely CAR, which increased significantly over time in the rapid group. Nevertheless, we did find some markers that may be useful in predicting the decline of the C-peptide. Moreover, these could potentially be important for understanding type 1 diabetes pathogenesis.

Profiling the Gut Microbiome Unraveled Signature Bacterial Groups in Autoimmune Diabetes, which Remain Unperturbed by the Low Ionic Strength of the Drinking Water in NOD mice.

BACKGROUND: Non-obese diabetic (NOD) mice develop type 1 diabetes (T1D) spontaneously and serve as a good model for investigating the underlying pathological mechanisms and devising novel treatment procedures. Although acid water consumption has been reported to exaggerate or reduce diabetes incidence in female NOD mice by two groups, the causative bacteria responsible for these contrasting changes remain unclear. On the contrary, we and others failed to observe the effect of acid water consumption on diabetes incidence. This study aimed to determine whether the consumption of low-pH drinking water could alter the frequencies of prominent bacterial groups independent of diabetes manifestation. METHODS: Six-week-old female NOD mice maintained on acidified drinking water at the Jackson Laboratories were transferred to neutral pH water or continuously provided with low pH drinking water at our facility. Diabetes was monitored weekly using a glucometer. Using the 454-pyrosequencing methodology, we profiled the gut microbiome of mice transferred to neutral water and developed diabetes. Further, we performed quantitative real-time polymerase chain reactions (qRT-PCR) using primers specific for prominent 16S rRNA genes on the fecal DNA of mice provided with low pH or neutral water and displayed diabetes similarly. RESULTS: Consistent with our earlier report, the incidence of T1D was robust (80-100%) regardless of whether female NOD mice consumed acid (~pH 2.9) or neutral water. The 454-pyrosequencing of fecal DNA indicated no substantial influence of transferring mice to neutral pH drinking water on the gut microbiome. To validate these findings, we conducted qRT-PCR on the fecal DNA of mice longitudinally from six weeks of age to adulthood that consumed acidic or neutral pH water and developed diabetes similarly. Among the 15 selected bacterial groups examined, the frequency of Lactobacillus sp. remained consistently lower (p < 0.05) throughout the life of NOD mice compared to that found in young (6-week-old) mice, regardless of the pH of the drinking water. The relative frequencies of the Firmicutes Ruminococcaceae and the Bactereoidetes members Anaerophaga sp. and Paludibacter sp. increased significantly (p < 0.05) during the transition to the overtly diabetic stage irrespective of the ionic strength of the drinking water. Interestingly, the Firmicutes members Clostridium coccoides, C. leptum, and Lachnospiraceae and the Bacteroidetes members Bacteroides sp. and Prevottella sp. remained unchanged throughout the analysis irrespective of the pH of the drinking water. Paradoxically, the representations of Akkermansia muciniphila and the segmented filamentous bacteria implicated in diabetes protection did not differ regardless of the age or the ionic strength of the drinking water. CONCLUSIONS: The data presented herein validate the lack of influence of acidic drinking water on T1D development in female NOD mice. Diabetes was associated with the lower representation of Lactobacillus sp. throughout life, which was not influenced by the differing pH of the drinking water. Significantly, segmented filamentous bacteria and A. muciniphila, previously implicated in protection against T1D, were not perturbed by the varying pH of the water consumed. These data indicate that although acidified water consumption was reported previously to diminish specific gastrointestinal pathogens, it failed to perturb gut commensals that influence diabetes development.

C-peptide in diabetes: A player in a dual hormone disorder?

C-peptide, a byproduct of insulin synthesis believed to be biologically inert, is emerging as a multifunctional molecule. C-peptide serves an anti-inflammatory and anti-atherogenic role in type 1 diabetes mellitus (T1DM) and early T2DM. C-peptide protects endothelial cells by activating AMP-activated protein kinase α, thus suppressing the activity of NAD(P)H oxidase activity and reducing reactive oxygen species (ROS) generation. It also prevents apoptosis by regulating hyperglycemia-induced p53 upregulation and mitochondrial adaptor p66shc overactivation, as well as reducing caspase-3 activity and promoting expression of B-cell lymphoma-2. Additionally, C-peptide suppresses platelet-derived growth factor (PDGF)-beta receptor and p44/p42 mitogen-activated protein (MAP) kinase phosphorylation to inhibit vascular smooth muscle cells (VSMC) proliferation. It also diminishes leukocyte adhesion by virtue of its capacity to abolish nuclear factor kappa B (NF-kB) signaling, a major pro-inflammatory cascade. Consequently, it is envisaged that supplementation of C-peptide in T1DM might ameliorate or even prevent end-organ damage. In marked contrast, C-peptide increases monocyte recruitment and migration through phosphoinositide 3-kinase (PI-3 kinase)-mediated pathways, induces lipid accumulation via peroxisome proliferator-activated receptor γ upregulation, and stimulates VSMC proliferation and CD4+ lymphocyte migration through Src-kinase and PI-3K dependent pathways. Thus, it promotes atherosclerosis and microvascular damage in late T2DM. Indeed, C-peptide is now contemplated as a potential biomarker for insulin resistance in T2DM and linked to increased coronary artery disease risk. This shift in the understanding of the pathophysiology of diabetes from being a single hormone deficiency to a dual hormone disorder warrants a careful consideration of the role of C-peptide as a unique molecule with promising diagnostic, prognostic, and therapeutic applications.

The Complex Network of Cytokines and Chemokines in Pediatric Patients with Long-Standing Type 1 Diabetes.

Type 1 diabetes (T1D) is a progressive disorder leading to the development of microangiopathies and macroangiopathies. Numerous cytokines and chemokines are involved in the pathogenesis of T1D complications. The study aimed to assess the presence of complications in patients with long-standing T1D and its relationship with serum biomarker concentrations. We examined 52 T1D subjects, with a disease duration ≥4 years and 39 healthy controls. The group of T1D patients was further divided into subgroups based on the duration of the disease (<7 years and ≥7 years) and the metabolic control assessed by the HbAlc level (<8% and ≥8%). We used Luminex Technology to assess a wide range of biomarker concentrations. A 24 h urine test was done to evaluate the rate of albuminuria. Optical coherence tomography (OCT) was conducted to detect early retinopathic changes. Subclinical atherosclerosis was assessed by measuring the carotid intima-media thickness (IMT). T1D patients showed remarkably higher concentrations of EGF, eotaxin/CCL11, MDC/CCL22, sCD40L, TGF-α, and TNF-α. Moreover, we reported statistically significant correlations between cytokines and IMT. Biomarker concentrations depend on numerous factors such as disease duration, metabolic control, and the presence of complications. Although the majority of pediatric T1D patients do not present signs of overt complications, it is indispensable to conduct the screening for angiopathies already in childhood, as its early recognition may attenuate the further progression of complications.

Kidney biopsy findings in children with diabetes mellitus.

BACKGROUND: Diabetic nephropathy may begin in childhood, but clinical kidney disease ascribable to this is uncommon in children with type 1 (insulin dependent) diabetes mellitus. METHODS: We reviewed our experience of kidney biopsies in children with type 1 diabetes mellitus. RESULTS: Between 1995 and 2022, there were biopsies in 17 children, with various clinical indications for kidney biopsy, making this the largest series of biopsies in diabetic children with clinical kidney abnormalities. Four biopsies showed diabetic nephropathy, three showed the combination of diabetic nephropathy and IgA nephropathy, and ten showed a variety of conditions other than diabetic nephropathy: minimal change disease (2), membranous nephropathy (2), thin glomerular basement membrane lesion (2), non-glomerular chronic damage in Wolcott-Rallison syndrome (2), acute pauciimmune necrotizing crescentic glomerulonephritis (1) and IgA nephropathy (1). Clinical clues of something other than diabetic nephropathy included acute kidney injury, microscopic haematuria or chronic kidney impairment with little or no proteinuria and the nephrotic syndrome after a short duration of diabetes. CONCLUSIONS: We confirm that changes better known in adults with either type 1 or type 2 diabetes mellitus can occur in children with type 1 diabetes mellitus: overt diabetic nephropathy either on its own or combined with other conditions and kidney disorders other than diabetic nephropathy.

Prevalence of Sarcopenia and Dynapenia and Related Clinical Outcomes in Patients with Type 1 Diabetes Mellitus.

BACKGROUND: Sarcopenia has recently been recognized as a complication of diabetes. However, there are few results about the prevalence of sarcopenia and dynapenia and the related clinical outcomes in type 1 diabetes mellitus (T1DM). Our objectives were to evaluate the prevalence of sarcopenia and dynapenia and to determine whether there are any associations with disease-related factors in people with T1DM. METHODS: A cross-sectional study was conducted in people with T1DM. We assessed appendicular skeletal mass index (ASMI) using bioimpedance 50 Hz (Nutrilab Akern). Muscle function was assessed through handgrip strength (HGS) using a Jamar dynamometer. Sarcopenia was defined as a low HGS with low ASMI, whereas dynapenia was defined as low HGS with a normal ASMI. We used HGS data from the Spanish population percentile table and a cut-off point at p5 as dynapenia. The association of clinical, metabolic, and lifestyle variables with sarcopenia and dynapenia was studied. RESULTS: This study included 62 T1DM patients (66% females, mean age of 38 ± 14 years, body mass index (BMI) of 24.9 ± 4.7 kg/m2). The prevalence of sarcopenia and dynapenia was 8% and 23%, respectively. In our sample, there were more men in the sarcopenic and dynapenic groups. The sarcopenic group showed a significantly higher mean HbA1c value. Lower diabetes duration, PREDIMED score, BMI, and muscle mass measures (fat-free mass index (FFMI), ASMI, and body cell mass index (BCMI)) were significantly associated with sarcopenia. Decreased diabetes duration, PREDIMED score, phase angle (PhA), and HGS values showed a significant association with dynapenia. CONCLUSIONS: The prevalence of sarcopenia and dynapenia was high in people with T1DM in our study. Specifically, the proportion of dynapenia was quite high. HGS and ASMI are practical tools for the assessment of muscle health status in T1DM, and low values are associated with poor glycemic control, underweight, and low adherence to the Mediterranean diet. Thus, dynapenia may predict accelerated muscle aging in T1DM.

Imaging in Type 1 Diabetes, Current Perspectives and Directions.

Type 1 diabetes (T1D) is characterized by the autoimmune-mediated attack of insulin-producing beta cells in the pancreas, leading to reliance on exogenous insulin to control a patient's blood glucose levels. As progress is being made in understanding the pathophysiology of the disease and how to better develop therapies to treat it, there is an increasing need for monitoring technologies to quantify beta cell mass and function throughout T1D progression and beta cell replacement therapy. Molecular imaging techniques offer a possible solution through both radiologic and non-radiologic means including positron emission tomography, magnetic resonance imaging, electron paramagnetic resonance imaging, and spatial omics. This commentary piece outlines the role of molecular imaging in T1D research and highlights the need for further applications of such methodologies in T1D.

Concurrent Foveoschisis and Atrophy in a Patient With X-Linked Retinoschisis and Type 1 Diabetes Mellitus.

We report the case of a 28-year-old man with X-linked retinoschisis (XLRS) and type I diabetes mellitus. The patient had bilateral foveoschisis with a tractional retinal fold in the right eye. Optical coherence tomography (OCT) revealed hyperreflective material within the inner nuclear and outer plexiform layers, photoreceptor atrophy, and retinal pigment epithelium irregularities in both eyes. Fluorescein angiography showed hyperfluorescent foveal spots corresponding to the hyperreflective material observed on OCT. This is a unique presentation of XLRS, with concurrent foveoschisis and photoreceptor atrophy in both eyes. The hyperreflective material on OCT serves as a distinctive feature of XLRS. [Ophthalmic Surg Lasers Imaging Retina 2023;54:603-606.].

Effect of lawsone-preconditioned mesenchymal stem cells on the regeneration of pancreatic ß cells in Type 1 diabetic rats.

Diabetes is one of the major health issues globally. Type 1 diabetes mellitus develops due to the destruction of pancreatic ß cells. Mesenchymal stem cells (MSCs) having remarkable self-renewal and differentiation potential, can regenerate ß cells. MSCs preconditioned with bioactive small molecules possess enhanced biological features and therapeutic potential under in vivo environment. Interestingly, compounds of naphthoquinone class possess antidiabetic and anti-inflammatory properties, and can be explored as potential candidates for preconditioning MSCs. This study analyzed the effect of lawsone-preconditioned human umbilical cord MSCs (hUMSCs) on the regeneration of ß cells in the streptozotocin (STZ)-induced Type 1 diabetes (T1D) rats. hUMSCs were isolated and characterized for the presence of surface markers. MSCs were preconditioned with optimized concentration of lawsone. T1D rat model was established by injecting 50 mg/kg of STZ intraperitoneally. Untreated and lawsone-preconditioned hUMSCs were transplanted into the diabetic rats via tail vein. Fasting blood sugar and body weight were monitored regularly for 4 weeks. Pancreas was harvested and ß cell regeneration was evaluated by hematoxylin and eosin staining, and gene expression analysis. Immunohistochemistry was also done to assess the insulin expression. Lawsone-preconditioned hUMSCs showed better anti-hyperglycemic effect in comparison with untreated hUMSCs. Histological analysis presented the regeneration of islets of Langerhans with upregulated expression of ßcell genes and reduced expression of inflammatory markers. Immunohistochemistry revealed strong insulin expression in the preconditioned hUMSCs compared with the untreated hUMSCs. It is concluded from the present study that lawsone-preconditioned hMSCs were able to exhibit pronounced anti-hyperglycemic effect in vivo compared with hUMSCs alone.

The role of the interferon/JAK-STAT axis in driving islet HLA-I hyperexpression in type 1 diabetes.

The hyperexpression of human leukocyte antigen class I (HLA-I) molecules on pancreatic beta-cells is widely accepted as a hallmark feature of type 1 diabetes pathogenesis. This response is important clinically since it may increase the visibility of beta-cells to autoreactive CD8+ T-cells, thereby accelerating disease progression. In this review, key factors which drive HLA-I hyperexpression will be explored, and their clinical significance examined. It is established that the presence of residual beta-cells is essential for HLA-I hyperexpression by islet cells at all stages of the disease. We suggest that the most likely drivers of this process are interferons released from beta-cells (type I or III interferon; possibly in response to viral infection) or those elaborated from influent, autoreactive immune cells (type II interferon). In both cases, Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) pathways will be activated to induce the downstream expression of interferon stimulated genes. A variety of models have highlighted that HLA-I expression is enhanced in beta-cells in response to interferons, and that STAT1, STAT2 and interferon regulatory factor 9 (IRF9) play key roles in mediating these effects (depending on the species of interferon involved). Importantly, STAT1 expression is elevated in the beta-cells of donors with recent-onset type I diabetes, and this correlates with HLA-I hyperexpression on an islet-by-islet basis. These responses can be replicated in vitro, and we consider that chronically elevated STAT1 may have a role in maintaining HLA-I hyperexpression. However, other data have highlighted that STAT2-IRF9 may also be critical to this process. Thus, a better understanding of how these factors regulate HLA-I under chronically stimulated conditions needs to be gathered. Finally, JAK inhibitors can target interferon signaling pathways to diminish HLA-I expression in mouse models. It seems probable that these agents may also be effective in patients; diminishing HLA-I hyperexpression on islets, reducing the visibility of beta-cells to the immune system and ultimately slowing disease progression. The first clinical trials of selective JAK inhibitors are underway, and the outcomes should have important implications for type 1 diabetes clinical management.

Sweat gland nerve fiber density and association with sudomotor function, symptoms, and risk factors in adolescents with type 1 diabetes.

PURPOSE: To quantify sweat gland nerve fiber density in adolescents with diabetes. Additionally, to investigate associations between sudomotor innervation, sweat responses, and possible risk factors for sudomotor neuropathy. METHODS: Cross-sectional study where 60 adolescents with type 1 diabetes (duration > 5 years) and 23 control subjects were included. Clinical data, quantitative sudomotor axon reflex test, and skin biopsies were obtained. Skin tissue was immunostained and imaged by confocal microscopy. Quantification of the sweat gland volume and three-dimensional reconstruction of the nerve fibers was performed using a design-unbiased technique. RESULTS: Adolescents with diabetes had a significant reduction of maximum and mean values of nerve fiber length and nerve fiber density in sweat glands compared to controls (p values < 0.05). No association between nerve fiber density and sweat responses was found (p = 0.21). In cases with reduced sweat gland nerve fiber length, nerve fiber density, and volume, the sweat response was reduced or absent. Height, systolic blood pressure, time in hypoglycemia, and total daily and basal/total insulin dose were positively correlated to sweat response, while low-density lipoprotein, and HbA1c were negatively correlated with sweat response (p values < 0.05). Other microvascular complications and high cholesterol levels increased the relative risk for reduced sweat gland nerve fiber density. CONCLUSION: Our findings of reduced sweat gland innervation in a selected group of adolescents add new knowledge about the structural changes that occur in autonomic nerves due to diabetes. Evaluating both the sweat gland innervation and sweat gland volume was important for understanding the association with sweat responses. Further research is needed to understand its clinical relevance.

Structural Changes of Cutaneous Immune Cells in Patients With Type 1 Diabetes and Their Relationship With Diabetic Polyneuropathy.

BACKGROUND AND OBJECTIVES: Diabetic polyneuropathy (DPN) is a complication of diabetes characterized by pain or lack of peripheral sensation, but the underlying mechanisms are not yet fully understood. Recent evidence showed increased cutaneous macrophage infiltration in patients with type 2 diabetes and painful DPN, and this study aimed to understand whether the same applies to type 1 diabetes. METHODS: The study included 104 participants: 26 healthy controls and 78 participants with type 1 diabetes (participants without DPN [n = 24], participants with painless DPN [n = 29], and participants with painful DPN [n = 25]). Two immune cells, dermal IBA1+ macrophages and epidermal Langerhans cells (LCs, CD207+), were visualized and quantified using immunohistological labeling and stereological counting methods on skin biopsies from the participants. The IBA1+ macrophage infiltration, LC number density, LC soma cross-sectional area, and LC processes were measured in this study. RESULTS: Significant difference in IBA1+ macrophage expression was seen between the groups (p = 0.003), with lower expression of IBA1 in participants with DPN. No differences in LC morphologies (LC number density, soma cross-sectional area, and process level) were found between the groups (all p > 0.05). In addition, IBA1+ macrophages, but not LCs, correlated with intraepidermal nerve fiber density, Michigan neuropathy symptom inventory, (questionnaire and total score), severity of neuropathy as assessed by the Toronto clinical neuropathy score, and vibration detection threshold in the whole study cohort. DISCUSSION: This study showed expressional differences of cutaneous IBA1+ macrophages but not LC in participants with type 1 diabetes-induced DPN compared with those in controls. The study suggests that a reduction in macrophages may play a role in the development and progression of autoimmune-induced diabetic neuropathy.

Pericyte dysfunction and impaired vasomotion are hallmarks of islets during the pathogenesis of type 1 diabetes.

Pancreatic islets are endocrine organs that depend on their microvasculature to function. Along with endothelial cells, pericytes comprise the islet microvascular network. These mural cells are crucial for microvascular stability and function, but it is not known if/how they are affected during the development of type 1 diabetes (T1D). Here, we investigate islet pericyte density, phenotype, and function using living pancreas slices from donors without diabetes, donors with a single T1D-associated autoantibody (GADA+), and recent onset T1D cases. Our data show that islet pericyte and capillary responses to vasoactive stimuli are impaired early on in T1D. Microvascular dysfunction is associated with a switch in the phenotype of islet pericytes toward myofibroblasts. Using publicly available RNA sequencing (RNA-seq) data, we further found that transcriptional alterations related to endothelin-1 signaling and vascular and extracellular matrix (ECM) remodeling are hallmarks of single autoantibody (Aab)+ donor pancreata. Our data show that microvascular dysfunction is present at early stages of islet autoimmunity.