Blood Monocyte Phenotype Is A Marker of Cardiovascular Risk in Type 2 Diabetes.

BACKGROUND: Diabetes is a major risk factor for atherosclerotic cardiovascular diseases with a 2-fold higher risk of cardiovascular events in people with diabetes compared with those without. Circulating monocytes are inflammatory effector cells involved in both type 2 diabetes (T2D) and atherogenesis. METHODS: We investigated the relationship between circulating monocytes and cardiovascular risk progression in people with T2D, using phenotypic, transcriptomic, and metabolomic analyses. cardiovascular risk progression was estimated with coronary artery calcium score in a cohort of 672 people with T2D. RESULTS: Coronary artery calcium score was positively correlated with blood monocyte count and frequency of the classical monocyte subtype. Unsupervised k-means clustering based on monocyte subtype profiles revealed 3 main endotypes of people with T2D at varying risk of cardiovascular events. These observations were confirmed in a validation cohort of 279 T2D participants. The predictive association between monocyte count and major adverse cardiovascular events was validated through an independent prospective cohort of 757 patients with T2D. Integration of monocyte transcriptome analyses and plasma metabolomes showed a disruption of mitochondrial pathways (tricarboxylic acid cycle, oxidative phosphorylation pathway) that underlined a proatherogenic phenotype. CONCLUSIONS: In this study, we provide evidence that frequency and monocyte phenotypic profile are closely linked to cardiovascular risk in patients with T2D. The assessment of monocyte frequency and count is a valuable predictive marker for risk of cardiovascular events in patients with T2D. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04353869.

Fully automated epicardial adipose tissue volume quantification with deep learning and relationship with CAC score and micro/macrovascular complications in people living with type 2 diabetes: the multicenter EPIDIAB study.

BACKGROUND: The aim of this study (EPIDIAB) was to assess the relationship between epicardial adipose tissue (EAT) and the micro and macrovascular complications (MVC) of type 2 diabetes (T2D). METHODS: EPIDIAB is a post hoc analysis from the AngioSafe T2D study, which is a multicentric study aimed at determining the safety of antihyperglycemic drugs on retina and including patients with T2D screened for diabetic retinopathy (DR) (n = 7200) and deeply phenotyped for MVC. Patients included who had undergone cardiac CT for CAC (Coronary Artery Calcium) scoring after inclusion (n = 1253) were tested with a validated deep learning segmentation pipeline for EAT volume quantification. RESULTS: Median age of the study population was 61 [54;67], with a majority of men (57%) a median duration of the disease 11 years [5;18] and a mean HbA1c of7.8 ± 1.4%. EAT was significantly associated with all traditional CV risk factors. EAT volume significantly increased with chronic kidney disease (CKD vs no CKD: 87.8 [63.5;118.6] vs 82.7 mL [58.8;110.8], p = 0.008), coronary artery disease (CAD vs no CAD: 112.2 [82.7;133.3] vs 83.8 mL [59.4;112.1], p = 0.0004, peripheral arterial disease (PAD vs no PAD: 107 [76.2;141] vs 84.6 mL[59.2; 114], p = 0.0005 and elevated CAC score (> 100 vs < 100 AU: 96.8 mL [69.1;130] vs 77.9 mL [53.8;107.7], p < 0.0001). By contrast, EAT volume was neither associated with DR, nor with peripheral neuropathy. We further evidenced a subgroup of patients with high EAT volume and a null CAC score. Interestingly, this group were more likely to be composed of young women with a high BMI, a lower duration of T2D, a lower prevalence of microvascular complications, and a higher inflammatory profile. CONCLUSIONS: Fully-automated EAT volume quantification could provide useful information about the risk of both renal and macrovascular complications in T2D patients.

Untargeted Multiomics Approach Coupling Lipidomics and Metabolomics Profiling Reveals New Insights in Diabetic Retinopathy.

Diabetic retinopathy (DR) is a microvascular complication of diabetes mellitus (DM) which is the main cause of vision loss in the working-age population. Currently known risk factors such as age, disease duration, and hemoglobin A1c lack sufficient efficiency to distinguish patients with early stages of DR. A total of 194 plasma samples were collected from patients with type 2 DM and DR (moderate to proliferative (PDR) or control (no or mild DR) matched for age, gender, diabetes duration, HbA1c, and hypertension. Untargeted lipidomic and metabolomic approaches were performed. Partial-least square methods were used to analyze the datasets. Levels of 69 metabolites and 85 lipid species were found to be significantly different in the plasma of DR patients versus controls. Metabolite set enrichment analysis indicated that pathways such as metabolism of branched-chain amino acids (methylglutaryl carnitine p = 0.004), the kynurenine pathway (tryptophan p < 0.001), and microbiota metabolism (p-Cresol sulfate p = 0.004) were among the most enriched deregulated pathways in the DR group. Moreover, Glucose-6-phosphate (p = 0.001) and N-methyl-glutamate (p < 0.001) were upregulated in DR. Subgroup analyses identified a specific signature associated with PDR, macular oedema, and DR associated with chronic kidney disease. Phosphatidylcholines (PCs) were dysregulated, with an increase of alkyl-PCs (PC O-42:5 p < 0.001) in DR, while non-ether PCs (PC 14:0-16:1, p < 0.001; PC 18:2-14:0, p < 0.001) were decreased in the DR group. Through an unbiased multiomics approach, we identified metabolites and lipid species that interestingly discriminate patients with or without DR. These features could be a research basis to identify new potential plasma biomarkers to promote 3P medicine.

Impact of diabetes on COVID-19 prognosis beyond comorbidity burden: the CORONADO initiative.

AIMS/HYPOTHESIS: Diabetes has been recognised as a pejorative prognostic factor in coronavirus disease 2019 (COVID-19). Since diabetes is typically a disease of advanced age, it remains unclear whether diabetes remains a COVID-19 risk factor beyond advanced age and associated comorbidities. We designed a cohort study that considered age and comorbidities to address this question. METHODS: The Coronavirus SARS-CoV-2 and Diabetes Outcomes (CORONADO) initiative is a French, multicentric, cohort study of individuals with (exposed) and without diabetes (non-exposed) admitted to hospital with COVID-19, with a 1:1 matching on sex, age (±5 years), centre and admission date (10 March 2020 to 10 April 2020). Comorbidity burden was assessed by calculating the updated Charlson comorbidity index (uCCi). A predefined composite primary endpoint combining death and/or invasive mechanical ventilation (IMV), as well as these two components separately, was assessed within 7 and 28 days following hospital admission. We performed multivariable analyses to compare clinical outcomes between patients with and without diabetes. RESULTS: A total of 2210 pairs of participants (diabetes/no-diabetes) were matched on age (mean±SD 69.4±13.2/69.5±13.2 years) and sex (36.3% women). The uCCi was higher in individuals with diabetes. In unadjusted analysis, the primary composite endpoint occurred more frequently in the diabetes group by day 7 (29.0% vs 21.6% in the no-diabetes group; HR 1.43 [95% CI 1.19, 1.72], p<0.001). After multiple adjustments for age, BMI, uCCi, clinical (time between onset of COVID-19 symptoms and dyspnoea) and biological variables (eGFR, aspartate aminotransferase, white cell count, platelet count, C-reactive protein) on admission to hospital, diabetes remained associated with a higher risk of primary composite endpoint within 7 days (adjusted HR 1.42 [95% CI 1.17, 1.72], p<0.001) and 28 days (adjusted HR 1.30 [95% CI 1.09, 1.55], p=0.003), compared with individuals without diabetes. Using the same adjustment model, diabetes was associated with the risk of IMV, but not with risk of death, within 28 days of admission to hospital. CONCLUSIONS/INTERPRETATION: Our results demonstrate that diabetes status was associated with a deleterious COVID-19 prognosis irrespective of age and comorbidity status. TRIAL REGISTRATION: ClinicalTrials.gov NCT04324736.

Prevalence, severity stages, and risk factors of diabetic retinopathy in 1464 adult patients with type 1 diabetes.

PURPOSE: To determine the prevalence of diabetic retinopathy (DR) and its risk factors in adult type 1 diabetes (T1D) patients METHODS: In this cross-sectional study, all T1D patients followed in the University Center for Diabetes and its Complications of Lariboisière Hospital (Paris, France) between January 2017 and February 2019 were included. Ophthalmologic and systemic data were collected from electronic records. The association between DR (and each grade) and associated factors were estimated by univariate and multivariate analyses using logistic regression models. RESULTS: A total of 1464 patients (46.2% of women, mean age: 42.2 ± 15.8 years) were included. The mean hemoglobin A1c (HbA1c) was 7.8 ± 1.7% and the mean diabetes duration was 20.5 ± 13.5 years. DR prevalence was 50.1% (47.4-52.6) and the prevalence of mild, moderate, and severe non-proliferative DR and proliferative DR was 19.1%, 9.4%, 3.9%, and 17.6%, respectively. DR was significantly associated with male gender, an older age, former and current smoking status, a higher BMI, the presence of nephropathy and neuropathy, higher HBA1c, and longer diabetes duration. Patients with HbA1c > 10% had an adjusted odds ratio (OR) of 3.25 (1.77-6.01) of having DR compared to patients with HbA1c < 6.5%. Patients with a diabetes duration > 30 years had an adjusted OR of 24.87 (14.82-42.67) higher of having DR compared to patients with a diabetes duration < 10 years. CONCLUSION: In this study, 50.1% of adult T1D patients had DR and 17.6% had proliferative DR. Diabetes duration and HbA1c were major risk factors.

Assessment of the Impact of Subcutaneous Catheter Change on Glucose Control in Patients with Type 1 Diabetes Treated by Insulin Pump in Open- and Closed-Loop Modes.

Introduction: Most continuous subcutaneous insulin infusion (CSII) catheters (KT) are changed every 3 days. This study aims at evaluating whether KT changes impact glucose control while under open-loop (OL) or automated insulin delivery (AID) modes. Methods: We included patients with type 1 diabetes who used Tandem t:slim x2 insulin pump and Dexcom G6 glucose sensor for 20 days in OL, then as AID. CSII and sensor glucose data in OL and for the past 20 days of 3-month AID were retrospectively analyzed. The percentage of time spent with sensor glucose above 180 mg/dL (%TAR180) was compared between the calendar day of KT change (D0), the next day (D1), and 2 days later (D2). Values were adjusted for age, gender, body mass index (BMI), hemoglobin A1c (HbA1c) at inclusion, and %TAR180 for the 2 h before KT change. Results: A total of 1636 KT changes were analyzed in 134 patients: 72 women (54%), age: 35.6 ± 15.7 years, BMI: 25.2 ± 4.7 kg/m2, and HbA1c: 7.5 ± 0.8%. %TAR180 in the 2 h before the KT change was 51.3 ± 37.0% in OL and 33.2 ± 30.0% in AID mode. In OL, significant absolute increases of %TAR180 at D0 versus D1 (+6.9%; P < 0.0001) or versus D2 (+6.8%; P < 0.0001) were observed. In AID, significant absolute increases of %TA180R at D0 versus D1 (+4.8%; P < 0.0001) or versus D2 (+4.2%; P < 0.0001) were also observed. Conclusion: This study shows an increase in time spent in hyperglycemia on the day of the KT change both in OL and AID modes. This additional information should be taken into account to improve current AID algorithms. ClinicalTrials.gov: NCT04939766.

Validation of the Body Scan®, a new device to detect small fiber neuropathy by assessment of the sudomotor function: agreement with the Sudoscan®.

Background: Sudomotor dysfunction is one of the earliest manifestations of small fiber neuropathy (SFN), reflecting the alteration of sympathetic C fiber innervation of the sweat glands. Among other techniques, such innervation can be assessed by measuring electrochemical skin conductance (ESC) in microsiemens (µS). In this study, ESC was measured at the feet to detect distal SFN. For this objective, the performance of a new device, the Body Scan® (Withings, France), intended for home use, was compared with that of a reference device, the Sudoscan® (Impeto Medical, France), which requires a hospital setting. Methods: In patients with diabetes with or without neuropathy or non-diabetic patients with lower-limb neuropathy, the diagnostic performance of the Body Scan® measurement was assessed by calculating its sensitivity (Se) and specificity (Sp) to detect at least moderate SFN (Se70 and Sp70), defined by a value of feet ESC ≤ 70 µS and > 50 µS on the Sudoscan® measure, or severe SFN (Se50 and Sp50), defined by a value of feet ESC ≤ 50 µS on the Sudoscan® measure. The agreement between the two devices was assessed with the analysis of Bland-Altman plots, mean absolute error (MAE), and root mean squared error (RMSE) calculations. The repeatability of the measurements was also compared between the two devices. Results: A total of 147 patients (52% men, mean age 59 years old, 76% diabetic) were included in the analysis. The sensitivity and specificity to detect at least moderate or severe SFN were: Se70 = 0.91 ([0.83, 0.96]), Sp70 = 0.97 ([0.88, 0.99]), Se50 = 0.91 ([0.80, 0.98]), and Sp50 = 0.99 ([0.94, 1]), respectively. The bias and 95% limits of agreement were 1.5 [-5.4, 8.4]. The MAE was 2.9 and the RMSE 3.8. The intra-sample variability was 2.0 for the Body Scan® and 2.3 for the Sudoscan®. Conclusion: The ESC measurements provided by the Body Scan® were in almost perfect agreement with those provided by the reference device, the Sudoscan®, which validates the accuracy of the Body Scan® for the detection of SFN. By enabling simple, rapid, and autonomous use by the patient at home, this new technique will facilitate screening and monitoring of SFN in daily practice. Clinical trial registration: ClinicalTrials.gov, identifier NCT05178459.

Prevalence and Description of the Skin Reactions Associated with Adhesives in Diabetes Technology Devices in an Adult Population: Results of the CUTADIAB Study.

Objective: The use of continuous glucose monitoring (CGM) systems and continuous subcutaneous insulin infusion (CSII) devices adhering to the skin can lead to skin reactions. The objective was to determine the prevalence and consequences of skin reactions at CGM or CSII sites in a large unbiased population. Research Design and Methods: This is a cross-sectional multicenter study. All adult patients with diabetes seen in consultation over a period of 7 months and using or having used a system with skin adhesives (in the last 10 years) were included and filled out a self-assessment questionnaire. Results: Among 851 patients, skin reaction was reported in 28% with CGM and 29% with CSII. Patients reporting reactions were more frequently women using CGM and CSII, and CGM users had type 1 more often than type 2 diabetes (P < 0.001). Manifestations were similar for reactions to CGM and CSII: redness and pruritus in 70%-75% of patients with reactions, pain in 20%-25%, and vesicles and desquamation in 12%-15%. Manifestations occurred within the first 24 h of first use in 22%-24% of patients with reactions to CGM and CSII, but after more than 6 months in 38% and 47% of patients with reactions to CGM and CSII, respectively. Device use was definitively stopped in 12% of patients with reactions to CGM (3.2% of all users) and 7% with reactions to CSII (2.1% of all users). Conclusions: Skin reactions were common, with similar presentations in CGM and CSII users. Manifestations suggested skin irritation rather than allergies. These reactions rarely led to the definitive discontinuation of the use of the device.

New ex vivo method to objectively assess insulin spatial subcutaneous dispersion through time during pump basal-rate based administration.

Glycemic variability remains frequent in patients with type 1 diabetes treated with insulin pumps. Heterogeneous spreads of insulin infused by pump in the subcutaneous (SC) tissue are suspected but were barely studied. We propose a new real-time ex-vivo method built by combining high-precision imaging with simultaneous pressure measurements, to obtain a real-time follow-up of insulin subcutaneous propagation. Human skin explants from post-bariatric surgery are imaged in a micro-computed tomography scanner, with optimised parameters to reach one 3D image every 5 min during 3 h of 1UI/h infusion. Pressure inside the tubing is recorded. A new index of dispersion (IoD) is introduced and computed upon the segmented 3D insulin depot per time-step. Infusions were hypodermal in 58.3% among 24 assays, others being intradermal or extradermal. Several minor bubbles and one occlusion were observed. IoD increases with time for all injections. Inter-assay variability is the smallest for hypodermal infusions. Pressure elevations were observed, synchronised with air bubbles arrivals in the tissue. Results encourage the use of this method to compare infusion parameters such as pump model, basal rate, catheter characteristics, infusion site characteristics or patient phenotype.

High Prevalence of NASH and Advanced Fibrosis in Type 2 Diabetes: A Prospective Study of 330 Outpatients Undergoing Liver Biopsies for Elevated ALT, Using a Low Threshold.

OBJECTIVE: Most people with type 2 diabetes (T2DM) and nonalcoholic steatohepatitis (NASH) or advanced fibrosis (AF) remain undiagnosed, resulting in missed opportunities for early intervention. This multicenter, prospective study assessed the yield of using routinely available data to identify these patients. RESEARCH DESIGN AND METHODS: A total of 713 outpatients with T2DM, screened in four diabetology clinics for nonalcoholic fatty liver disease according to American Diabetes Association criteria, were referred to hepatologists for further work-up (Fibrosis-4 and vibration-controlled transient elastography [VCTE]). A liver biopsy was proposed when ALT levels were persistently >20 IU/L in female patients or >30 IU/L in male patients, in the absence of other liver disease. RESULTS: Liver biopsies were performed in 360 patients and considered adequate for reading after central review for 330 specimens (median patient age, 59 years; male patients, 63%; median BMI and HbA1c values, 32 and 7.5%, respectively). Prevalence of NASH, AF, and cirrhosis were 58%, 38%, and 10%, respectively. Liver lesions were independently associated with the components of metabolic syndrome but not with the micro- and macrovascular complications of T2DM. Models based on routinely available data with or without VCTE had good accuracy to predict AF (respectively: area under the receiver operating characteristic curve [AUROC], 0.84 and 0.77; and correctly classified 59% and 45%) and NASH (respectively: AUROC, 0.82 and 0.81; 44% and 42%). CONCLUSIONS: Despite the use of a low ALT threshold, prevalence of NASH (58%) or AF (38%) was high. Routinely available data had a high yield in identifying patients with T2DM with AF and/or NASH requiring further liver assessment.

Is the Consensual Threshold for Defining High Glucose Variability Implementable in Clinical Practice?

OBJECTIVE: Estimating glycemic variability (GV) through within-day coefficient of variation (%CVw) is recommended for patients with type 1 Diabetes (T1D). High GV (hGV) is defined as %CVw > 36%. However, continuous glucose monitoring (CGM) devices provide exclusively total CV (%CVT). We aimed to assess consequences of this disparity. RESEARCH DESIGN AND METHODS: We retrospectively calculated both %CVT and %CVw of consecutive T1D patients from their CGM raw data during 14 days. Patients with hGV with %CVT >36% and %CVw ≤36% were called the "inconsistent GV group". RESULTS: A total of 104 patients were included. Mean ± SD %CVT and %CVw were 42.4 ± 8% and 37.0 ± 7.4% respectively (P < 0.0001). Using %CVT, 81 patients (73.6%) were classified as having hGV, whereas 59 (53.6%) using %CVw (P < 0.0001) corresponding to 22 patients (21%) in the inconsistent GV population. CONCLUSIONS: Evaluation of GV through %CV in patients with T1D is highly dependent on the calculation method and then must be standardized.

Reliability and Safety of Bedside Blind Bone Biopsy Performed by a Diabetologist for the Diagnosis and Treatment of Diabetic Foot Osteomyelitis.

OBJECTIVE: Bone biopsy (BB) performed by a surgeon or an interventional radiologist is recommended for suspicion of osteomyelitis underlying diabetic foot ulcer (DFU). To facilitate its practice, we developed a procedure allowing bedside blind bone biopsy (B4) by a diabetologist. RESEARCH DESIGN AND METHODS: We conducted a three-step observational study consisting of a feasibility and safety phase (phase 1) to assess the success and side effects of B4, a validity phase (phase 2) to compare DFU outcomes between positive (B4+) and negative (B4-) bone cultures, and a performance phase (phase 3) to compare B4 with the conventional surgical or radiological procedure basic bone biopsy (B3). Primary end points were the presence of bone tissue (phase 1) and complete DFU healing with exclusive medical treatment at 12 months (phases 2 and 3). RESULTS: In phase 1, 37 consecutive patients with clinical and/or radiological suspicion of DFU osteomyelitis underwent B4. Bone tissue was collected in all patients with few side effects. In phase 2, a B4+ bone culture was found in 40 of 79 (50.6%) participants. Among B4+ patients, complete wound healing after treatment was 57.5%. No statistical difference was observed with patients with B4- bone culture not treated with antibiotics (71.8%, P = 0.18). In phase 3, the proportion of patients with positive BB was lower in B4 (40 of 79, 50.6%) than in B3 (34 of 44, 77.3%, P < 0.01). However, complete healing was similar (64.6% vs. 54.6%, P = 0.28). No difference in rate of culture contamination was observed. CONCLUSIONS: B4 is a simple, safe, and efficient procedure for the diagnosis of DFU osteomyelitis with a similar proportion of healing to conventional BB.

The use of statins in the elderly is associated with less severe hypoglycemia in patient with diabetes.

Three hundred and eighty-nine older patients with diabetes attending an ambulatory diabetes center were included to determine risk factors of severe hypoglycemia (SH). Thirty-three (8.5%) patients had at least one severe hypoglycemia. In multivariate analyze, statin was associated with lower risk and insulin was associated with higher risk of SH.

Monocytopenia, monocyte morphological anomalies and hyperinflammation characterise severe COVID-19 in type 2 diabetes.

Early in the COVID-19 pandemic, type 2 diabetes (T2D) was marked as a risk factor for severe disease and mortality. Inflammation is central to the aetiology of both conditions where variations in immune responses can mitigate or aggravate disease course. Identifying at-risk groups based on immunoinflammatory signatures is valuable in directing personalised care and developing potential targets for precision therapy. This observational study characterised immunophenotypic variation associated with COVID-19 severity in T2D. Broad-spectrum immunophenotyping quantified 15 leucocyte populations in peripheral circulation from a cohort of 45 hospitalised COVID-19 patients with and without T2D. Lymphocytopenia and specific loss of cytotoxic CD8+ lymphocytes were associated with severe COVID-19 and requirement for intensive care in both non-diabetic and T2D patients. A morphological anomaly of increased monocyte size and monocytopenia restricted to classical CD14Hi CD16- monocytes was specifically associated with severe COVID-19 in patients with T2D requiring intensive care. Increased expression of inflammatory markers reminiscent of the type 1 interferon pathway (IL6, IL8, CCL2, INFB1) underlaid the immunophenotype associated with T2D. These immunophenotypic and hyperinflammatory changes may contribute to increased voracity of COVID-19 in T2D. These findings allow precise identification of T2D patients with severe COVID-19 as well as provide evidence that the type 1 interferon pathway may be an actionable therapeutic target for future studies.

Long-term Metabolic and Socioeducational Outcomes of Transient Neonatal Diabetes: A Longitudinal and Cross-sectional Study.

OBJECTIVE: Transient neonatal diabetes mellitus (TNDM) occurs during the 1st year of life and remits during childhood. We investigated glucose metabolism and socioeducational outcomes in adults. RESEARCH DESIGN AND METHODS: We included 27 participants with a history of TNDM currently with (n = 24) or without (n = 3) relapse of diabetes and 16 non-TNDM relatives known to be carriers of causal genetic defects and currently with (n = 9) or without (n = 7) diabetes. Insulin sensitivity and secretion were assessed by hyperinsulinemic-euglycemic clamp and arginine-stimulation testing in a subset of 8 TNDM participants and 7 relatives carrying genetic abnormalities, with and without diabetes, compared with 17 unrelated control subjects without diabetes. RESULTS: In TNDM participants, age at relapse correlated positively with age at puberty (P = 0.019). The mean insulin secretion rate and acute insulin response to arginine were significantly lower in TNDM participants and relatives of participants with diabetes than in control subjects (median 4.7 [interquartile range 3.7-5.7] vs. 13.4 [11.8-16.1] pmol/kg/min, P < 0.0001; and 84.4 [33.0-178.8] vs. 399.6 [222.9-514.9] µIU/mL, P = 0.0011), but were not different between participants without diabetes (12.7 [10.4-14.3] pmol/kg/min and 396.3 [303.3-559.3] µIU/mL, respectively) and control subjects. Socioeducational attainment was lower in TNDM participants than in the general population, regardless of diabetes duration. CONCLUSIONS: Relapse of diabetes occurred earlier in TNDM participants compared with relatives and was associated with puberty. Both groups had decreased educational attainment, and those with diabetes had lower insulin secretion capacity; however, there was no difference in insulin resistance in adulthood. These forms of diabetes should be included in maturity-onset diabetes of the young testing panels, and relatives of TNDM patients should be screened for underlying defects, as they may be treated with drugs other than insulin.

Interplay between Liver X Receptor and Hypoxia Inducible Factor 1α Potentiates Interleukin-1ß Production in Human Macrophages.

Low-grade inflammation is constitutive of atherosclerosis, and anti-inflammatory therapy inhibiting interleukin-1ß (IL-1ß) reduces the rate of cardiovascular events. While cholesterol accumulation in atheroma plaque and macrophages is a major driver of the inflammatory process, the role of the LXR cholesterol sensors remains to be clarified. Murine and human macrophages were treated with LXR agonists for 48 h before Toll-like receptor (TLR) stimulation. Unexpectedly, we observe that, among other cytokines, LXR agonists selectively increase IL1B mRNA levels independently of TLR activation. This effect, restricted to human macrophages, is mediated by activation of HIF-1α through LXR. Accordingly, LXR agonists also potentiate other HIF-1α-dependent pathways, such as glycolysis. Treatment of human macrophages with carotid plaque homogenates also leads to induction of IL1B in an LXR-dependent manner. Thus, our work discloses a mechanism by which cholesterol and oxysterols trigger inflammation in atherosclerosis. This suggests perspectives to target IL-1ß production in atherosclerotic patients.

Glucagon-like Peptide 1 Receptor Agonists, Diabetic Retinopathy and Angiogenesis: The AngioSafe Type 2 Diabetes Study.

AIMS: Recent trials provide conflicting results on the association between glucagon-like peptide 1 receptor agonists (GLP-1RA) and diabetic retinopathy (DR). The aim of the AngioSafe type 2 diabetes (T2D) study was to determine the role of GLP-1RA in angiogenesis using clinical and preclinical models. METHODS: We performed two studies in humans. In study 1, we investigated the effect of GLP-1RA exposure from T2D diagnosis on the severity of DR, as diagnosed with retinal imaging (fundus photography). In study 2, a randomized 4-week trial, we assessed the effect of liraglutide on circulating hematopoietic progenitor cells (HPCs), and angio-miRNAs.We then studied the experimental effect of Exendin-4, on key steps of angiogenesis: in vitro on human endothelial cell proliferation, survival and three-dimensional vascular morphogenesis; and in vivo on ischemia-induced neovascularization of the retina in mice. RESULTS: In the cohort of 3154 T2D patients, 10% displayed severe DR. In multivariate analysis, sex, disease duration, glycated hemoglobin (HbA1c), micro- and macroangiopathy, insulin therapy and hypertension remained strongly associated with severe DR, while no association was found with GLP-1RA exposure (o 1.139 [0.800-1.622], P = .47). We further showed no effect of liraglutide on HPCs, and angio-miRNAs. In vitro, we demonstrated that exendin-4 had no effect on proliferation and survival of human endothelial cells, no effect on total length and number of capillaries. Finally, in vivo, we showed that exendin-4 did not exert any negative effect on retinal neovascularization. CONCLUSIONS: The AngioSafe T2D studies provide experimental and clinical data confirming no effect of GLP-1RA on angiogenesis and no association between GLP-1 exposure and severe DR.

Isolation and Analysis of Human Monocytes and Adipose Tissue Macrophages.

Monocytes and macrophages are cells of the innate immune system, existing in circulation and permeating every tissue of the human body. These cells represent the first responders to stress, and their inflammatory activation forms part of virtually every human disease. It is for these reasons that several approaches have been developed in order to phenotypically and functionally analyze these cells and their subpopulations. These inflammatory cells have been consistently demonstrated to undergo inflammatory polarization through the engagement of lipid-activated nuclear receptors, namely, through PPARs and LXRs, which regulate both lipid metabolism and inflammation. Quantitative and phenotypic analyses of monocytes and macrophages are largely dependent on cytometric tools and antibody-based labelling of membrane markers, while functional analyses apply a range of in vitro approaches coupled with secondary analyses of gene or cytokine expression. An important aspect of phenotypic and functional analyses is the purification, enrichment, or appropriate differentiation of biological materials, ensuring experimentation is carried out on monocytes and/or macrophages and not on other cell types occupying the same physical niches. This chapter will focus on the most common analytical approaches applied to the mononuclear phagocytic system, namely, circulating monocytes and adipose tissue macrophages.