Severe and fatal COVID-19 is characterised by increased circulating glucagon like peptide 1 and procalcitonin modulated by type 2 diabetes.

AIMS: Endotoxemia commonly occurs in severe and fatal COVID-19, suggesting that concomitant bacterial stimuli may amplify the innate immune response induced by SARS-CoV-2. We previously demonstrated that the endogenous glucagon like peptide 1 (GLP-1) system in conjunction with increased procalcitonin (PCT) is hyperactivated in patients with severe Gram-negative sepsis and modulated by type 2 diabetes (T2D). We aimed to determine the association of COVID-19 severity with endogenous GLP-1 activation upregulated by increased specific pro-inflammatory innate immune response in patients with and without T2D. MATERIALS AND METHODS: Plasma levels of total GLP-1, IL-6, and PCT were estimated on admission and during hospitalisation in 61 patients (17 with T2D) with non-severe and severe COVID-19. RESULTS: COVID-19 patients demonstrated ten-fold increase of IL-6 levels regardless of disease severity. Increased admission GLP-1 levels (p = 0.03) accompanied by two-fold increased PCT were found in severe as compared with non-severe patients. Moreover, GLP-1 and PCT levels were significantly increased in non-survived as compared with survived patients at admission (p = 0.01 and p = 0.001, respectively) and at 5 to 6 days of hospitalisation (p = 0.05). Both non-diabetic and T2D patients demonstrated a positive correlation between GLP-1 and PCT response (r = 0.33, p = 0.03, and r = 0.54, p = 0.03, respectively), but the intensity of this joint pro-inflammatory/GLP-1 response was modulated by T2D. In addition, hypoxaemia down-regulated GLP-1 response only in T2D patients with bilateral lung damage. CONCLUSIONS: The persistent joint increase of endogenous GLP-1 and PCT in severe and fatal COVID-19 suggests a role of concomitant bacterial infection in disease exacerbation. Early elevation of endogenous GLP-1 may serve as a new biomarker of COVID-19 severity and fatal outcome.

Coronary atherosclerosis severity is closely associated with decreased GLP-1R positivity among CD16+ pro-inflammatory and patrolling monocyte subsets.

Background and aims: Glucagon Like Peptide-1 Receptor (GLP-1R) activation reduces pro-inflammatory responses of human monocytes, their accumulation in the vascular wall and foam cell formation inhibiting atherosclerogenesis. This suggests that reduction of circulating GLP-1-1R positive monocytes may have pro-atherogenic effects. It is unknown whether different CD14/CD16 monocytes subsets display GLP-1R and whether their relative proportions correlate with atherosclerosis severity. We evaluated the association between GLP-1R positivity in different CD14/CD16 monocyte subsets and coronary atherosclerosis severity. Methods: Relative amounts of classical (CD14+/CD16-), intermediate pro-inflammatory (CD14+/CD16+) and non-classical patrolling (CD14-/CD16+) subsets of total circulating monocytes and the proportions of GLP-1R positive monocytes in these subsets were determined in 13 control subjects and 10 dyslipidemic ischemic heart disease (IHD) patients with severe angiographic proven coronary atherosclerosis using flow cytometry analysis. Atherosclerosis severity was calculated by SYNTAX score. Results: In univariable analysis, severe atherosclerosis was associated with decreased proportion of classical monocytes and two fold increased CD16+ pro-inflammatory and patrolling subsets as compared with controls (p = 0.01, p = 0.02 and p = 0.01, respectively). Frequency of GLP-1R positive monocytes was decreased in both CD16+ subsets (p = 0.02 and p = 0.05, respectively) and negatively correlated with atherosclerosis severity (r = -0.65, p = 0.005 and r = -0.44, p = 0.05, respectively). Conclusions: Increased skewing of the classical monocyte population toward CD16+ pro-inflammatory and patrolling subsets accompanied by decreased in GLP-1R positivity are associated with coronary atherosclerosis severity in IHD patients with dyslipidemia. Although the effect of potential confounders cannot be ruled out, our data suggest that failure of GLP-1R-dependent anti-inflammatory/anti-atherogenic control results in innate immune system dysfunction and can promote atherosclerogenesis.

Hyper-Activation of Endogenous GLP-1 System to Gram-negative Sepsis Is Associated With Early Innate Immune Response and Modulated by Diabetes.

BACKGROUND: Culture-positive gram-negative sepsis induces greater magnitude of early innate immunity /inflammatory response compared with culture-negative sepsis. We previously demonstrated increased activation of anti-inflammatory Glucagon Like Peptide-1 (GLP-1) hormone in initial phase of sepsis more pronounced in diabetes patients. However, whether GLP-1 system is hyperactivated during the early innate immune response to gram-negative sepsis and modulated by diabetes remains unknown. OBJECTIVES: Total and active GLP-1, soluble Dipeptidyl peptidase 4 (sDPP-4) enzyme, and innate immunity markers presepsin (sCD14) and procalcitonin (PCT) in plasma were determined by ELISA on admission and after 2 to 4 days in 37 adult patients with and without type 2 diabetes and gram-negative or culture-negative sepsis of different severity. RESULTS: Severe but not non-severe sepsis was associated with markedly increased GLP-1 system response, which correlated with PCT and the organ dysfunction marker lactate. Culture-positive gram-negative bacteria but not culture-negative sepsis induced hyper-activation of GLP-1 system, which correlated with increased innate immune markers sCD14, PCT, and lactate. GLP-1 inhibitory enzyme sDPP-4 was down regulated by sepsis and correlated negatively with sCD14 in gram-negative sepsis. Diabetic patients demonstrated increased GLP-1 response but significantly weaker innate immune response to severe and gram-negative sepsis. CONCLUSIONS: Early stage of gram-negative sepsis is characterized by endogenous GLP-1 system hyperactivity associated with over activation of innate immune response and organ dysfunction, which are modulated by diabetes. Total GLP-1 may be novel marker for rapid diagnosis of gram-negative sepsis and its severity.

Endogenous glucagon-like peptide-1 system response is impaired during ST-elevation myocardial infarction in type 2 diabetes patients.

We previously demonstrated increased glucagon-like peptide-1 (GLP-1) secretion during acute ST elevation myocardial infarction (STEMI) in non-diabetic (ND) patients. Whether the endogenous GLP-1 system response is different in patients with type 2 diabetes (T2D) during STEMI is unknown. Patients with STEMI (20 ND, 13 T2D) and 3 control groups (non-STEMI [14 ND, 13 T2D], stable angina pectoris [SAP] [8 ND, 10 T2D] patients and healthy subjects) (n = 25) were studied. Plasma levels of total and active GLP-1 and soluble dipeptidyl peptidase-4 (sDPP4) were estimated by enzyme-linked immunosorbent assay on admission and at 24 and 48 hours after percutaneous coronary intervention in all patients. Sharply elevated levels of total and active GLP-1 were found in ND STEMI patients at 24 h (P < 0.05 and P < 0.005, respectively), but not in T2D STEMI patients. All patients demonstrated decreased sDPP4 levels compared with healthy controls (P < 0.0005) accompanied by increased active/total GLP-1 ratio regardless of their ischemic state. These data demonstrate that T2D patients fail to further upregulate their endogenous GLP-1 system during STEMI. This may underlie their worse cardiovascular outcome.

Sepsis-induced activation of endogenous GLP-1 system is enhanced in type 2 diabetes.

BACKGROUND: High levels of circulating GLP-1 are associated with severity of sepsis in critically ill nondiabetic patients. Whether patients with type 2 diabetes (T2D) display different activation of the endogenous GLP-1 system during sepsis and whether it is affected by diabetes-related metabolic parameters are not known. METHODS: Serum levels of GLP-1 (total and active forms) and its inhibitor enzyme sDPP-4 were determined by ELISA on admission and after 2 to 4 days in 37 sepsis patients with (n = 13) and without T2D (n = 24) and compared to normal healthy controls (n = 25). Correlations between GLP-1 system activation and clinical, inflammatory, and diabetes-related metabolic parameters were performed. RESULTS: A 5-fold (P < .001) and 2-fold (P < .05) increase in active and total GLP-1 levels, respectively, were found on admission as compared to controls. At 2 to 4 days from admission, the level of active GLP-1 forms in surviving patients were decreased significantly (P < .005), and positively correlated with inflammatory marker CRP (r = 0.33, P = .05). T2D survivors displayed a similar but more enhanced pattern of GLP-1 response than nondiabetic survivors. Nonsurvivors demonstrate an early extreme increase of both total and active GLP-1 forms, 9.5-fold and 5-fold, respectively (P < .05). The initial and late levels of circulating GLP-1 inhibitory enzyme sDPP-4 were twice lower in all studied groups (P < .001), compared with healthy controls. CONCLUSIONS: Taken together, these data indicate that endogenous GLP-1 system is activated during sepsis. Patients with T2D display an enhanced and prolonged activation as compared to nondiabetic patients. Extreme early increased GLP-1 levels during sepsis indicate poor prognosis.

Nutrient induced type 2 and chemical induced type 1 experimental diabetes differently modulate gastric GLP-1 receptor expression.

T2DM patients demonstrate reduced GLP-1 receptor (GLP-1R) expression in their gastric glands. Whether induced T2DM and T1DM differently affect the gastric GLP-1R expression is not known. This study assessed extrapancreatic GLP-1R system in glandular stomach of rodents with different types of experimental diabetes. T2DM and T1DM were induced in Psammomys obesus (PO) by high-energy (HE) diet and by streptozotocin (STZ) in Sprague Dawly (SD) rats, respectively. GLP-1R expression was determined in glandular stomach by RT PCR and immunohistomorphological analysis. The mRNA expression and cellular association of the GLP-1R in principal glands were similar in control PO and SD rats. However, nutrient and chemical induced diabetes resulted in opposite alterations of glandular GLP-1R expression. Diabetic PO demonstrated increased GLP-1R mRNA expression, intensity of cellular GLP-1R immunostaining, and frequency of GLP-1R positive cells in the neck area of principal glands compared with controls. In contrast, SD diabetic rats demonstrated decreased GLP-1 mRNA, cellular GLP-1R immunoreactivity, and frequency of GLP-1R immunoreactive cells in the neck area compared with controls. In conclusion, nutrient and chemical induced experimental diabetes result in distinct opposite alterations of GLP-1R expression in glandular stomach. These results suggest that induced T1DM and T2DM may differently modulate GLP-1R system in enteropancreatic axis.

Increased ERK and JNK activation and decreased ERK/JNK ratio are associated with long-term organ damage in patients with systemic lupus erythematosus.

OBJECTIVE: The activities of two mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), correlate with disease severity in SLE patients. Whether they are also associated with long-term organ damage is unknown. The aim of the present work was to determine whether impaired expression and activity of ERK and JNK correlate with long-term damage in SLE. METHODS: The expression of ERK and JNK and their phosphorylated active forms was determined by western blot analysis four times during the first year of follow-up in peripheral blood mononuclear cells from 36 SLE patients. A correlation analysis was performed between ERK and JNK expression and longterm organ damage estimated by the SLICC/ARC Damage Index (SDI) 4 years later. RESULTS: Mean levels of ERK and JNK activities during the first year correlated with long-term organ damage severity (r = 0.38 and r = 0.35, respectively; P = 0.05). Overall JNK expression increased with the severity of chronic damage (P = 0.01; P = 0.05 for SDI score 2 and 3, respectively). In contrast, overall ERK expression significantly decreased in patients with maximal organ damage (SDI score 3) compared with patients with an SDI score of 2 (P = 0.03). The ERK/JNK ratio decreased by approximately 40% and 30% in patients with an SDI score of 3 as compared with patients without organ damage and healthy controls, respectively. CONCLUSION: These results demonstrate that early activation of ERK and JNK along with decreased overall ERK expression and reduced ERK/JNK ratio may predict the severity of long-term organ damage in SLE patients.

GLP-1 receptor is expressed in human stomach mucosa: analysis of its cellular association and distribution within gastric glands.

The stomach is a target organ of the incretin hormone glucagon-like peptide-1 (GLP-1). However, the cellular expression and glandular distribution of its receptor (GLP-1R) in human gastric mucosa are not known. We determined the expression of GLP-1R in different regions of human stomach mucosa and its specific cellular association and distribution within gastric glands. Tissue samples from stomach body and antrum were obtained from 20 patients during routine esophagogastroduodenoscopy. mRNA encoding GLP-1R protein expression was evaluated by RT-PCR. Determination of cell types bearing GLP-1R, their localization, and their frequency in gastric glands in different gastric regions were estimated by immunohistochemical morphological analysis. Levels of GLP-1R mRNA were similar in body and antrum. GLP-1R immunoreactivity was found throughout the gastric mucosa in various types of glandular cells. The highest frequency of GLP-1R immunoreactive cells was found in the neck area of the principal glands in cells morphologically identified as parietal cells. GLP-1R immunostaining was also found on enteroendocrine-like cells in the pyloric glands. This study provides the first description of GLP-1R expression in human gastric glands and its specific cellular association. Our data suggest that GLP-1 may act directly on the gastric mucosa to modulate its complex functions.

Young patients with both type 1 diabetes mellitus and asthma have a unique IL-12 and IL-18 secretory pattern.

BACKGROUND: The expression of the regulatory cytokines interleukin (IL)-12 and IL-18 in patients with both Th1- and Th2-mediated diseases, type 1 diabetes mellitus (T1DM) and asthma, is unknown. OBJECTIVE: To investigate the in vivo and in vitro IL-12 and IL-18 secretion patterns in patients with both T1DM and asthma. METHODS: Peripheral blood mononuclear cells (PBMC) were collected from 44 patients. Mean age 19.4 ± 4.7 yr (10.5-28 yr), divided into four paired groups: T1DM and asthma, asthma only, T1DM only, and healthy controls. T-cell proliferative response was assessed. IL-12 and IL-18 serum levels and expression by PBMC following in vitro stimulation by lipopolysaccharide (LPS) were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: Patients with T1DM and asthma had higher serum levels of both IL-12 and IL-18 compared to controls: 146.2 ± 69.2 and 109.7 ± 34.6 pg/mL, p = 0.038 and 436.1 ± 117.9, 320.2 ± 99.1 pg/mL, p = 0.028, respectively. Stimulated IL-12 secretion was significantly lower in these patients compared to those with one disease only: 809 ± 426.4, 2111.6 ± 2214.3, 3188.1 ± 2692.9 pg/mL and after 48 h: 956.3 ± 489.3, 2429.8 ± 2394.6, 3874.5 ± 2820.3 pg/mL, respectively, p < 0.03 for all. The IL-18/IL-12 serum ratio was also significantly higher in patients with both diseases compared to those with asthma only, p = 0.017. CONCLUSION: Patients with both T1DM and asthma display a different pattern of IL-12 and IL-18 expression compared to patients with one disease only and controls.

A strategy for the engineering of insulin producing cells with a broad spectrum of defense properties.

Insulin-producing pancreatic beta cells are known to be extremely susceptible to the oxidative stress and hypoxia generated following islet transplantation in diabetic patients. We hereby present a novel in vivo selection strategy based on the isolation of insulin-producing cells with enhanced protection after repeated rounds of encapsulation and xenotransplantation. Rat insulinoma INS-1 cells were encapsulated in alginate macrobeads and transplanted in the peritoneal cavity of mice. After 2 days the beads were retrieved and cells were recovered from alginate and propagated in vitro until submitted to a second round of encapsulation and transplantation. Three days later, the surviving cells, named INS-1m2, were isolated from the alginate beads and their protection and functional activity examined. Compared to parental INS-1 cells, the selected INS-1m2 cells were more resistant to hydrogen peroxide, nitric oxide, alloxan and hypoxia. This enhanced protection of the selected cells correlated with the increased level of catalase and poly (ADP-ribose) polymerase expression. Although selected cells expressed more insulin than parental cells, no change in their insulin response to glucose was observed. We conclude that the in vivo selection strategy is a powerful tool for the engineering of insulin producing cells with a broad spectrum of defense properties.

Stimulation of cytokine production in human peripheral blood mononuclear cells by an aqueous Chlorella extract.

CPE is an aqueous extract of the edible micro alga Chlorella pyrenoidosa, which has been shown to have immunostimulatory effects in vivo. In the present study, CPE was evaluated for an ability to stimulate cytokine production by human peripheral blood mononuclear cells (PBMC). PBMC from healthy individuals were treated ex vivo for 24 hours with 1, 10 and 100 microg/mL CPE. This resulted in a marked increase in the level of IL-10, a regulatory cytokine, and strong stimulation of the T-helper-1 (Th1) cell cytokines, IFN-gamma and TNF-alpha. In contrast, stimulation of representative T-helper-2 (Th2) cell cytokines, IL-4 and IL-13, was minor. CPE (1, 10 or 100 microg/mL) did not cause a proliferation of human PBMC suggesting that enhanced secretion of cytokines was not secondary to an increase in cell number. We conclude that CPE stimulation of human PBMC induces a Th1-patterned cytokine response and a strong anti-inflammatory regulatory cytokine response, observations that await confirmation in vivo.

TH1/TH2 cytokine balance in patients with both type 1 diabetes mellitus and asthma.

BACKGROUND AND OBJECTIVE: T1DM and asthma are mediated by opposite arms of the cellular immune system namely T helper (Th)1 and Th2 CD4(+) cells, respectively. Our aim was to characterize the Th1/Th2 cytokine balance in patients with both T1DM and asthma. METHODS: Forty-four patients, mean age 19 years were matched by gender and age, to 4 paired groups: T1DM and asthma, asthma only, T1DM only and healthy controls. Peripheral blood mononuclear cells (PBMC) were stimulated in vitro with disease-specific recombinant antigens; glutamic acid decarboxylase and house dust mite (Der p1 antigen) for T1DM and asthma, respectively, and non-specific mitogens; phytohemaglutinin (PHA), tetanus toxin and anti-CD3 mAb. ELISPOT and ELISA technique were used to determine INF-gamma, IL-2, IL-4, IL-13 and IL-10 expression. RESULTS: Patients with T1DM and asthma demonstrated a similar cytokine pattern but lower Th1/Th2 ratio compared to patients with T1DM only. The Th2 cytokines response to Der p1 was enhanced in patients with both diseases compared to controls. The IL-10 overall secretion was higher in patients with both diseases compared to one disease only. CONCLUSION: The Th1 and Th2 secretory pattern of patients with T1DM and asthma combines features of both diseases suggesting a unique Th1/Th2 balance.

Amelioration of SLE-like manifestations in (NZBxNZW)F1 mice following treatment with a peptide based on the complementarity determining region 1 of an autoantibody is associated with a down-regulation of apoptosis and of the pro-apoptotic factor JNK kinase.

Treatment with peptides based on the complementarity determining regions (CDR) of murine and human monoclonal anti-DNA antibodies that bear the common idiotype, 16/6 Id, ameliorates disease manifestations of mice with either induced or spontaneous SLE. Aberrant expression and function of the p21Ras/MAP kinase pathway are associated with active SLE. Therefore, we examined the effect of treatment with a CDR1-based peptide of a human autoantibody (hCDR1) on the p21Ras pathway and SLE manifestations of SLE-prone (NZBxNZW)F1 mice. Untreated SLE-afflicted mice demonstrated increased expression of p21Ras and the phosphorylated active form of its down-stream element JNK kinase in conjunction with reduced hSOS and unchanged p120GAP, as compared to healthy controls. Amelioration of SLE manifestations following treatment with hCDR1 was associated with a diminished expression of phosphorylated JNK kinase, mainly in the T cell population that also exhibited reduced rates of apoptosis. Thus, hCDR1 therapy ameliorates SLE, at least in part, via down-regulation of the activity of the pro-apoptotic JNK kinase.

Sensitivity of HaCat keratinocytes to diabetogenic toxins.

Metabolic, genetic and environmental factors very likely play an important role in the development of skin lesions in diabetes mellitus. While these lesions are involved in secondary diabetes complications, various diabetogenic genotoxic agents may induce direct skin damage. In the present study we examined the potential of known diabetogenic agents (streptozotocin (STZ) and alloxan (AL)), with different mechanisms of action, for induction of direct injury in an immortal human keratinocyte HaCat cell line. In contrast to STZ, which induces alkylation of DNA, a genotoxic effect of AL is achieved through reactive oxygen species. We found that HaCat cells are highly sensitive to STZ, but not to AL. At a concentration of 10mM STZ, cell viability decreased to 32 +/-13% of control (P<0.05), as compared to 82 +/-14% with 10mM of AL. Cells treated with 10 and 20mM STZ showed a significant increase in apoptosis (3.9- and 6.7-fold), but not in necrosis, compared to naive cells (P<0.05). In contrast to STZ, no increase in apoptotic and necrotic cell death was observed after AL treatment. Pretreatment with non-metabolizable 3-O-methyl glucose (3-OMG), which can blockade glucose transporter, or with poly(ADP-ribose) polymerase inhibitors (nicotinamide or 3-aminobenzamide), did not protect keratinocytes from STZ injury. Our results show that STZ, but not AL, is highly toxic to the HaCat cell line. Unlike insulin-producing cells, STZ-induced injury of immortal human keratinocyte HaCat cells is independent of the glucose transporters as well as of the activation of poly(ADP-ribose) polymerase.