Glucagon-like peptide 1 receptor is a T cell-negative costimulatory molecule.

Glucagon-like peptide-1 receptor (GLP-1R) is a key regulator of glucose metabolism known to be expressed by pancreatic ß cells. We herein investigated the role of GLP-1R on T lymphocytes during immune response. Our data showed that a subset of T lymphocytes expresses GLP-1R, which is upregulated during alloimmune response, similarly to PD-1. When mice received islet or cardiac allotransplantation, an expansion of GLP-1Rpos T cells occurred in the spleen and was found to infiltrate the graft. Additional single-cell RNA sequencing (scRNA-seq) analysis conducted on GLP-1Rpos and GLP-1Rneg CD3+ T cells unveiled the existence of molecular and functional dissimilarities between both subpopulations, as the GLP-1Rpos are mainly composed of exhausted CD8 T cells. GLP-1R acts as a T cell-negative costimulatory molecule, and GLP-1R signaling prolongs allograft survival, mitigates alloimmune response, and reduces T lymphocyte graft infiltration. Notably, GLP-1R antagonism triggered anti-tumor immunity when tested in a preclinical mouse model of colorectal cancer.

TMEM219 regulates the transcription factor expression and proliferation of beta cells.

Pancreatic beta cells replenishment is considered the next therapeutic option for type 1 diabetes; while stimulating endogenous beta cells proliferation is the "holy grail" for those patients with exhausted beta cell mass. Here we are demonstrating that the pro-apoptotic receptor TMEM219 is expressed in fetal pancreas, in beta cell precursors and in in vitro embryonic-derived endocrine progenitors. TMEM219 signaling negatively regulates beta cells at early stages and induces Caspase 8-mediated cell death. Pharmacological blockade of TMEM219 further rescued beta cell precursor and proliferation markers, and decreased cell death, both in islets and in in vitro-derived endocrine progenitors, allowing for beta cell preservation. While addressing the upstream controlling TMEM219 expression, we determined the TMEM219 miRNet; indeed, one of those miRNAs, miR-129-2, is highly expressed in human islets, particularly in patients at risk or with established type 1 diabetes. miR-129-2 mimic downregulated TMEM219 expression in islets, in in vitro embryonic-derived endocrine progenitors and in highly proliferating insulinoma-derived cells. Moreover, miR-129-2 inhibitor induced a TMEM219 overexpression in insulinoma-derived cells, which restored cell proliferation and functional markers, thus acting as endogenous regulator of TMEM219 expression. The TMEM219 upstream regulator miR129-2 controls the fate of beta cell precursors and may unleash their regenerative potentials to replenish beta cells in type 1 diabetes.

Type 2 diabetes mellitus pharmacological remission with dapagliflozin plus oral semaglutide.

Dapagliflozin, a sodium-glucose co-transporter-2 inhibitor and semaglutide, a glucagon-like peptide 1 receptor agonist, have both demonstrated efficacy in glycemic control, reducing blood pressure, body weight, risk of renal and heart failure in type 2 diabetes mellitus. In this observational, real-world, study we aimed to investigate the efficacy of the combination therapy with those two agents over glycemic control. We thus obtained the data of 1335 patients with type 2 diabetes followed by 11 Diabetes centers in Lombardia, Italy. A group of 443 patients was treated with dapagliflozin alone, the other group of 892 patients was treated with the combination therapy of dapagliflozin plus oral semaglutide. We analyzed changes in glycated hemoglobin from baseline to 6 months of follow-up, as well as changes in fasting glycemia, body weight, body mass index, systolic and diastolic pressure, heart rate, creatinine, estimated glomerular filtration rate and albuminuria. Both groups of patients showed an improvement of glycometabolic control after 6 months of treatment; indeed, the treatment with dapagliflozin plus oral semaglutide showed a reduction of glycated hemoglobin of 1.2% as compared to the 0.5% reduction observed in the dapagliflozin alone group. Significant changes were observed in body mass index, fasting plasmatic glucose, blood pressure, total cholesterol, LDL and albumin to creatinine ratio, with a high rate (55%) of near-normalization of glycated hemoglobin. Our real world data confirmed the potential of the oral combination therapy dapagliflozin with semaglutide in inducing pharmacological remission of type 2 diabetes mellitus.

Daytime hypoglycemic episodes during the use of an advanced hybrid closed loop system.

AIMS: The use of advanced hybrid closed loop systems is spreading due to the beneficial effects on glycometabolic control obtained in patients with type 1 diabetes. However, hypoglycemic episodes can be sometimes a matter of concern. We aim to compare the hypoglycemic risk of an advanced hybrid closed loop system and a predictive low glucose suspend sensor augmented pump. METHODS: In this retrospective three months observational study, we included 30 patients using Medtronic Minimed™ 780G advanced hybrid closed loop system and 30 patients using a Medtronic Minimed™ predictive low glucose suspend sensor augmented pump. RESULTS: The advanced hybrid closed loop system reduced the time spent above 180 mg/dL threshold and increased the time in range as compared to the predictive low glucose suspend. No severe hypoglycemia occurred in both groups and no differences were observed in the percentage of time spent below 70 mg/dl and 54 mg/dl glucose threshold. Nevertheless, more hypoglycemic episodes were recorded during daytime, but not in nighttime, with the use of the advanced hybrid closed loop system. CONCLUSIONS: Our results confirmed the general improvement of glycemic outcomes obtained with the advanced hybrid closed loop system; however more hypoglycemic episodes during daytime were evident.

Broadening horizons in mechanisms, management, and treatment of diabetic kidney disease.

Diabetic kidney disease (DKD) is the first cause of end-stage kidney disease in patients with diabetes and its prevalence is increasing worldwide. It encompasses histological alterations that mainly affect the glomerular filtration unit, which include thickening of the basement membrane, mesangial cell proliferation, endothelial alteration, and podocyte injury. These morphological abnormalities further result in a persistent increase of urinary albumin-to-creatinine ratio and in a reduction of the estimated glomerular filtration rate. Several molecular and cellular mechanisms have been recognized, up to date, as major players in mediating such clinical and histological features and many more are being under investigation. This review summarizes the most recent advances in understanding cell death mechanisms, intracellular signaling pathways and molecular effectors that play a role in the onset and progression of diabetic kidney damage. Some of those molecular and cellular mechanisms have been already successfully targeted in preclinical models of DKD and, in some cases, strategies have been tested in clinical trials. Finally, this report sheds light on the relevance of novel pathways that may become therapeutic targets for future applications in DKD.

Targeting a novel apoptotic pathway in human disease.

Apoptotic pathways have always been regarded as a key-player in preserving tissue and organ homeostasis. Excessive activation or resistance to activation of cell death signaling may indeed be responsible for several mechanisms of disease, including malignancy and chronic degenerative diseases. Therefore, targeting apoptotic factors gained more and more attention in the scientific community and novel strategies emerged aimed at selectively blocking or stimulating cell death signaling. This is also the case for the TMEM219 death receptor, which is activated by a circulating ligand, the Insulin-like growth factor binding protein 3 (IGFBP3) and induces a caspase-8-dependent apoptosis of the target cells. Interestingly, stimulation of the IGFBP3/TMEM219 axis exerts an anti-proliferative effect, while blockade of the TMEM219 deleterious signal protects TMEM219-expressing cells of the endocrine pancreas, lung, and intestine from damage and death. Here, we summarize the most updated reports on the role of the IGFBP3/TMEM219 apoptotic axis in disease conditions, including intestinal disorders and diabetes, and we describe the advancements in designing and testing novel TMEM219-based targeting approaches in emerging potential clinical applications.

eATP and autoimmune diabetes.

PURPOSE OF REVIEW: The purine nucleotide adenosine triphosphate (ATP) is released into extracellular spaces as extracellular ATP (eATP) as a consequence of cell injury or death and activates the purinergic receptors. Once released, eATP may facilitate T-lymphocyte activation and differentiation. The purpose of this review is to elucidate the role of ATP-mediated signaling in the immunological events related to type 1 diabetes (T1D). RECENT FINDINGS: T lymphocytes mediate immune response during the onset of T1D and promote pancreatic islet or whole pancreas rejection in transplantation. Recent data suggest a potential role for eATP in early steps of T1D onset and of allograft rejection. In different preclinical experimental models and clinical trials, several drugs targeting purinergic signaling have been employed to abrogate lymphocyte activation and differentiation, thus representing an achievable treatment to prevent/revert T1D or to induce long-term islet allograft function. SUMMARY: In preclinical and clinical settings, eATP-signaling inhibition induces immune tolerance in autoimmune disease and in allotransplantation. In this view, the purinergic system may represent a novel therapeutic target for auto- and allo-immunity.

Neuroblastoma suppressor of tumorigenicity 1 is a circulating protein associated with progression to end-stage kidney disease in diabetes.

Circulating proteins associated with transforming growth factor-ß (TGF-ß) signaling are implicated in the development of diabetic kidney disease (DKD). It remains to be comprehensively examined which of these proteins are involved in the pathogenesis of DKD and its progression to end-stage kidney disease (ESKD) in humans. Using the SOMAscan proteomic platform, we measured concentrations of 25 TGF-ß signaling family proteins in four different cohorts composed in total of 754 Caucasian or Pima Indian individuals with type 1 or type 2 diabetes. Of these 25 circulating proteins, we identified neuroblastoma suppressor of tumorigenicity 1 (NBL1, aliases DAN and DAND1), a small secreted protein known to inhibit members of the bone morphogenic protein family, to be most strongly and independently associated with progression to ESKD during 10-year follow-up in all cohorts. The extent of damage to podocytes and other glomerular structures measured morphometrically in 105 research kidney biopsies correlated strongly with circulating NBL1 concentrations. Also, in vitro exposure to NBL1 induced apoptosis in podocytes. In conclusion, circulating NBL1 may be involved in the disease process underlying progression to ESKD, and its concentration in circulation may identify subjects with diabetes at increased risk of progression to ESKD.

Inflammation and vascular dysfunction: The negative synergistic combination of diabetes and COVID-19.

AIMS: Several reports indicate that diabetes determines an increased mortality risk in patients with coronavirus disease 19 (COVID-19) and a good glycaemic control appears to be associated with more favourable outcomes. Evidence also supports that COVID-19 pneumonia only accounts for a part of COVID-19 related deaths. This disease is indeed characterised by abnormal inflammatory response and vascular dysfunction, leading to the involvement and failure of different systems, including severe acute respiratory distress syndrome, coagulopathy, myocardial damage and renal failure. Inflammation and vascular dysfunction are also well-known features of hyperglycemia and diabetes, making up the ground for a detrimental synergistic combination that could explain the increased mortality observed in hyperglycaemic patients. MATERIALS AND METHODS: In this work, we conduct a narrative review on this intriguing connection. Together with this, we also present the clinical characteristics, outcomes, laboratory and histopathological findings related to this topic of a cohort of nearly 1000 subjects with COVID-19 admitted to a third-level Hospital in Milan. RESULTS: We found an increased mortality in subjects with COVID-19 and diabetes, together with an altered inflammatory profile. CONCLUSIONS: This may support the hypothesis that diabetes and COVID-19 meet at the crossroads of inflammation and vascular dysfunction. (ClinicalTrials.gov NCT04463849 and NCT04382794).

Dapagliflozin acutely improves kidney function in type 2 diabetes mellitus. The PRECARE study.

Dapagliflozin has been demonstrated to improve glycemic control, blood pressure, and body weight in type 2 diabetes mellitus (T2D); indeed, it can also reduce the risk of progression to renal failure, of hospitalization for heart failure and of cardiovascular death. We aim to investigate the acute effect of Dapagliflozin on kidney function in the common clinical practice in T2D. This is a study including 1402 patients with T2D recruited from 11 centers in Lombardia, Italy, who were evaluated at baseline and after 6 months of treatment with Dapagliflozin 10 mg per day. The primary outcome of the study was the change in HbA1c, while the secondary outcomes were modification of weight, BMI, systolic and diastolic pressure, creatinine, eGFR and albuminuria status. After 24 weeks of treatment with Dapagliflozin, a reduction in Hb1Ac was observed (-0.6 ± 1.8%) as well as in BMI (-1.5 ± 5.2 kg/m2). Statistically significant changes were also found for systolic and diastolic blood pressure, cholesterol and triglycerides. Interestingly, a statistically significant acute improvement of kidney function was evident. Our analyses confirm the beneficial effects of dapagliflozin after 6 months of therapy, with improvements of glycemic and lipid profiles, blood pressure, BMI. Finally, an acute positive effect on albuminuria and KIDGO classes was observed during a 6 months treatment with dapagliflozin in patients with T2D.

The anti-inflammatory and immunological properties of GLP-1 Receptor Agonists.

In the last few years, a great interest has emerged in investigating the pleiotropic effects of Glucagon Like Peptide-1 Receptor Agonists (GLP-1RAs). While GLP-1RAs ability to lower plasma glucose and to induce weight loss has allowed them to be approved for the treatment of diabetes and obesity, consistent evidences from in vitro studies and preclinical models suggested that GLP-1RAs have anti-inflammatory properties and that may modulate the immune-system. Notably, such anti-inflammatory effects target different pathways in different tissues, underling the broad spectrum of GLP-1RAs actions. This review examines some of the currently proposed molecular mechanisms of GLP-1RAs actions and explores their potential benefits in reducing inflammatory responses, which may well suggest a future therapeutic use of GLP-1RAs in new indications.

Abnormalities of the oculomotor function in type 1 diabetes and diabetic neuropathy.

AIMS: Abnormalities in the oculomotor system may represent an early sign of diabetic neuropathy and are currently poorly studied. We designed an eye-tracking-based test to evaluate oculomotor function in patients with type 1 diabetes. METHODS: We used the SRLab-Tobii TX300 Eye tracker®, an eye-tracking device, coupled with software that we developed to test abnormalities in the oculomotor system. The software consists of a series of eye-tracking tasks divided into 4 classes of parameters (Resistance, Wideness, Pursuit and Velocity) to evaluate both smooth and saccadic movement in different directions. We analyzed the oculomotor system in 34 healthy volunteers and in 34 patients with long-standing type 1 diabetes. RESULTS: Among the 474 parameters analyzed with the eye-tracking-based system, 11% were significantly altered in patients with type 1 diabetes (p < 0.05), with a higher proportion of abnormalities observed in the Wideness (24%) and Resistance (10%) parameters. Patients with type 1 diabetes without diabetic neuropathy showed more frequently anomalous measurements in the Resistance class (p = 0.02). The classes of Velocity and Pursuit were less frequently altered in patients with type 1 diabetes as compared to healthy subjects, with anomalous measurements mainly observed in patients with diabetic neuropathy. CONCLUSIONS: Abnormalities in oculomotor system function can be detected in patients with type 1 diabetes using a novel eye-tracking-based test. A larger cohort study may further determine thresholds of normality and validate whether eye-tracking can be used to non-invasively characterize early signs of diabetic neuropathy. TRIAL: NCT04608890.

Indirect and Direct Effects of SARS-CoV-2 on Human Pancreatic Islets.

Recent studies have shown that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may induce metabolic distress, leading to hyperglycemia in patients affected by coronavirus disease 19 (COVID-19). We investigated the potential indirect and direct effects of SARS-CoV-2 on human pancreatic islets in 10 patients who became hyperglycemic after COVID-19. Although there was no evidence of peripheral anti-islet autoimmunity, the serum of these patients displayed toxicity on human pancreatic islets, which could be abrogated by the use of anti-interleukin-1ß (IL-1ß), anti-IL-6, and anti-tumor necrosis factor α, cytokines known to be highly upregulated during COVID-19. Interestingly, the receptors of those aforementioned cytokines were highly expressed on human pancreatic islets. An increase in peripheral unmethylated INS DNA, a marker of cell death, was evident in several patients with COVID-19. Pathology of the pancreas from deceased hyperglycemic patients who had COVID-19 revealed mild lymphocytic infiltration of pancreatic islets and pancreatic lymph nodes. Moreover, SARS-CoV-2-specific viral RNA, along with the presence of several immature insulin granules or proinsulin, was detected in postmortem pancreatic tissues, suggestive of ß-cell-altered proinsulin processing, as well as ß-cell degeneration and hyperstimulation. These data demonstrate that SARS-CoV-2 may negatively affect human pancreatic islet function and survival by creating inflammatory conditions, possibly with a direct tropism, which may in turn lead to metabolic abnormalities observed in patients with COVID-19.

Immunogenicity and Safety of SARS-CoV-2 mRNA Vaccines in a Cohort of Patients With Type 1 Diabetes.

Patients with type 1 diabetes (T1D) may develop severe outcomes during coronavirus disease 2019 (COVID-19), but their ability to generate an immune response against the SARS-CoV-2 mRNA vaccines remains to be established. We evaluated the safety, immunogenicity, and glycometabolic effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines in patients with T1D. A total of 375 patients (326 with T1D and 49 subjects without diabetes) who received two doses of the SARS-CoV-2 mRNA vaccines (mRNA-1273, BNT162b2) between March and April 2021 at ASST Fatebenefratelli Sacco were included in this monocentric observational study. Local and systemic adverse events were reported in both groups after SARS-CoV-2 mRNA vaccination, without statistical differences between them. While both patients with T1D and subjects without diabetes exhibited a parallel increase in anti-SARS-CoV-2 spike titers after vaccination, the majority of patients with T1D (70% and 78%, respectively) did not show any increase in the SARS-CoV-2-specific cytotoxic response compared with the robust increase observed in all subjects without diabetes. A reduced secretion of the T-cell-related cytokines interleukin-2 and tumor necrosis factor-α in vaccinated patients with T1D was also observed. No glycometabolic alterations were evident in patients with T1D using continuous glucose monitoring during follow-up. Administration of the SARS-CoV-2 mRNA vaccine is associated with an impaired cellular SARS-CoV-2-specific cytotoxic immune response in patients with T1D.

The IGFBP3/TMEM219 pathway regulates beta cell homeostasis.

Loss of pancreatic beta cells is a central feature of type 1 (T1D) and type 2 (T2D) diabetes, but a therapeutic strategy to preserve beta cell mass remains to be established. Here we show that the death receptor TMEM219 is expressed on pancreatic beta cells and that signaling through its ligand insulin-like growth factor binding protein 3 (IGFBP3) leads to beta cell loss and dysfunction. Increased peripheral IGFBP3 was observed in established and at-risk T1D/T2D patients and was confirmed in T1D/T2D preclinical models, suggesting that dysfunctional IGFBP3/TMEM219 signaling is associated with abnormalities in beta cells homeostasis. In vitro and in vivo short-term IGFBP3/TMEM219 inhibition and TMEM219 genetic ablation preserved beta cells and prevented/delayed diabetes onset, while long-term IGFBP3/TMEM219 blockade allowed for beta cell expansion. Interestingly, in several patients' cohorts restoration of appropriate IGFBP3 levels was associated with improved beta cell function. The IGFBP3/TMEM219 pathway is thus shown to be a physiological regulator of beta cell homeostasis and is also demonstrated to be disrupted in T1D/T2D. IGFBP3/TMEM219 targeting may therefore serve as a therapeutic option in diabetes.

Prevalence and significance of mesentery thickening and lymph nodes enlargement in Crohn's disease.

BACKGROUND: Mesentery thickening and enlarged lymphnodes are typical findings of Crohn's disease (CD), but their role is unknown. Aim of the present study was to evaluate their prevalence and significance on postoperative complications and long-term surgical recurrence after CD surgery. METHODS: 1272 consecutive, unselected patients were retrospectively reviewed, divided into 4 groups based on the presence or absence of a thickened mesentery and enlarged lymphnodes, and stratified for primary or recurrent surgical procedure. In all patients but those treated with strictureplasty the mesentery and lymphnodes were removed. Patients' characteristics, peri-operative findings, and long-term recurrence were compared by univariate and multivariate analysis. RESULTS: Thickened mesentery and enlarged lymphnodes were not present in all cases, were typical of ileal location and penetrating behaviour, had a constant decrease over recurrences, were independent of either pre-operative medical therapy or surgical approach, did not increase the duration of surgery and complications, presented similar 20-years recurrence rate to normal mesentery and lymphnodes. Lymphopathy was associated to a worst nutritional status during disease recurrences. At multivariate analysis, age, location, and behaviour, but not mesenteric characteristics, were related to an increased risk of surgical recurrence. CONCLUSIONS: This study provides new information on mesentery and lymphnodes in CD patients. Further studies are needed to clarify the appropriate surgical approach.

Novel Soluble Mediators of Innate Immune System Activation in Solid Allograft Rejection.

During the past years, solid allograft rejection has been considered the consequence of either cellular- or antibody-mediated reaction both being part of the adaptive immune response, whereas the role of innate immunity has been mostly considered less relevant. Recently, a large body of evidence suggested that the innate immune response and its soluble mediators may play a more important role during solid allograft rejection than originally thought. This review will highlight the role of novel soluble mediators that are involved in the activation of innate immunity during alloimmune response and solid allograft rejection. We will also discuss emerging strategies to alleviate the aforementioned events. Hence, novel, feasible, and safe clinical therapies are needed to prevent allograft loss in solid organ transplantation. Fully understanding the role of soluble mediators of innate immune system activation may help to mitigate solid allograft rejection and improve transplanted recipients' outcomes.

PD-1 blockade counteracts post-COVID-19 immune abnormalities and stimulates the anti-SARS-CoV-2 immune response.

A substantial proportion of patients who have recovered from coronavirus disease-2019 (COVID-19) experience COVID-19-related symptoms even months after hospital discharge. We extensively immunologically characterized patients who recovered from COVID-19. In these patients, T cells were exhausted, with increased PD-1+ T cells, as compared with healthy controls. Plasma levels of IL-1ß, IL-1RA, and IL-8, among others, were also increased in patients who recovered from COVID-19. This altered immunophenotype was mirrored by a reduced ex vivo T cell response to both nonspecific and specific stimulation, revealing a dysfunctional status of T cells, including a poor response to SARS-CoV-2 antigens. Altered levels of plasma soluble PD-L1, as well as of PD1 promoter methylation and PD1-targeting miR-15-5p, in CD8+ T cells were also observed, suggesting abnormal function of the PD-1/PD-L1 immune checkpoint axis. Notably, ex vivo blockade of PD-1 nearly normalized the aforementioned immunophenotype and restored T cell function, reverting the observed post-COVID-19 immune abnormalities; indeed, we also noted an increased T cell-mediated response to SARS-CoV-2 peptides. Finally, in a neutralization assay, PD-1 blockade did not alter the ability of T cells to neutralize SARS-CoV-2 spike pseudotyped lentivirus infection. Immune checkpoint blockade ameliorates post-COVID-19 immune abnormalities and stimulates an anti-SARS-CoV-2 immune response.

Next-gen therapeutics to spare and expand beta-cell mass.

The most effective and physiological way to treat hyperglycemia is to restore beta-cell function and to rescue production of endogenous insulin. Increasing evidence suggests that both type 1 and type 2 diabetes are characterized by a significant defect in beta-cell mass, leading to the manifestation of the disease. Novel alternative approaches are needed to spare and expand beta-cell mass in patients with diabetes. This review sets out to describe the latest findings on how to restore the beta-cell mass and function in both forms of diabetes to modulate their progression.