Hyperglycemia inhibits complement-mediated immunological control of S. aureus in a rat model of peritonitis

Assessing the predictive value of time-in-range level for the risk of postoperative infection in patients with type 2 diabetes: a cohort study

Aim

To analyze the correlation between preoperative time-in-range (TIR) levels and postoperative infection in patients with type 2 diabetes mellitus (T2DM) and to evaluate the value of the TIR as a predictor of postoperative infection in patients with T2DM.

Methods

A total of 656 patients with T2DM during the perioperative period were divided into a TIR standard group (TIR≥70%) and a TIR nonstandard group (TIR<70%) according to the TIR value. Modified Poisson regression was used to analyze postoperative risk factors in patients with T2DM. All patients were subsequently divided into a training set and a validation set at a ratio of 7:3. LASSO regression and the Boruta algorithm were used to screen out the predictive factors related to postoperative infection in T2DM patients in the training set. The discrimination and calibration of the model were evaluated by the area under the receiver operating characteristic curve (ROC) and calibration curve, and the clinical net benefit of the model was evaluated and verified through the decision analysis (DCA) curve. Finally, a forest plot was used for relevant subgroup analysis.

Results

Modified Poisson regression analysis revealed that the TIR was a risk factor for postoperative infection in T2DM patients, and when the TIR was <70%, the risk of postoperative infection increased by 52.2% (P <0.05). LASSO regression and Boruta algorithm screening variables revealed that the TIR, lymphocytes, neutrophils, total serum cholesterol, superoxide dismutase and type of incision were predictive factors for postoperative infection in patients with T2DM (P<0.05). The calibration curve confirmed that the model predictions were consistent with reality, and the decision curve confirmed that the model had better clinical benefits. Finally, the results of the subgroup analysis revealed that in each subgroup, the risk of postoperative infection was greater when the TIR was <70% than when the TIR was ≥70%, and there was no interaction between subgroups.

Conclusion

The TIR is related to postoperative infection and can be used as a new indicator to predict the risk of postoperative infection in patients with type 2 diabetes mellitus.

Naturally acquired antibodies against 4 Streptococcus pneumoniae serotypes in Pakistani adults with type 2 diabetes mellitus

Immune response elicited during pneumococcal carriage has been shown to protect against subsequent colonization and infection by Streptococcus pneumoniae. The study was designed to measure the baseline serotype-specific anti-capsular IgG concentration and opsonic titers elicited in response to asymptomatic carriage in adults with and without type 2-diabetes. Level of IgG to capsular polysaccharide was measured in a total of 176 samples (124 with type 2 diabetes and 52 without type 2 diabetes) against serotype 1, 19F, 9V, and 18C. From within 176 samples, a nested cohort of 39 samples was selected for measuring the functional capacity of antibodies by measuring opsonic titer to serotypes 19F, 9V, and 18C. Next, we measured levels of IgG to PspA in 90 samples from individuals with and without diabetes (22 non-diabetes and 68 diabetes). Our results demonstrated comparable IgG titers against all serotypes between those with and without type 2-diabetes. Overall, we observed higher opsonic titers in those without diabetes as compared to individuals with diabetes for serotypes 19F and 9V. The opsonic titers for 19F and 9V significantly negatively correlated with HbA1c. For 19F, 41.66% (n = 10) showed opsonic titers ≥ 1:8 in the diabetes group as compared to 66.66% (n = 10) in the non-diabetes group. The percentage was 29.6% (n = 7) vs 66.66% (n = 10) for 9V and 70.83% (n = 17) vs 80% (n = 12) for 18C in diabetes and non-diabetes groups respectively. A comparable anti-PspA IgG (p = 0.409) was observed in those with and without diabetes, indicating that response to protein antigen is likely to remain intact in those with diabetes. In conclusion, we demonstrated comparable IgG titers to both capsular polysaccharide and protein antigens in those with and without diabetes, however, the protective capacity of antibodies differed between the two groups.

High sugar diet alters immune function and the gut microbiome in juvenile green iguanas (Iguana iguana)

The present work aimed to study whether a high sugar diet can alter immune responses and the gut microbiome in green iguanas. Thirty-six iguanas were split into four treatment groups using a 2×2 design. Iguanas received either a sugar-supplemented diet or a control diet, and either a lipopolysaccharide (LPS) injection or a phosphate-buffered saline (PBS) injection. Iguanas were given their respective diet treatment through the entire study (∼3 months) and received a primary immune challenge 1 and 2 months into the experiment. Blood samples and cloacal swabs were taken at various points in the experiment and used to measure changes in the immune system (bacterial killing ability, lysis and agglutination scores, LPS-specific IgY concentrations), and alterations in the gut microbiome. We found that a sugar diet reduces bacterial killing ability following an LPS challenge, and sugar and the immune challenge temporarily alters gut microbiome composition while reducing alpha diversity. Although sugar did not directly reduce lysis and agglutination following the immune challenge, the change in these scores over a 24-h period following an immune challenge was more drastic (it decreased) relative to the control diet group. Moreover, sugar increased constitutive agglutination outside of the immune challenges (i.e. pre-challenge levels). In this study, we provide evidence that a high sugar diet affects the immune system of green iguanas (in a disruptive manner) and alters the gut microbiome.

Diabetes and Cancer: A Twisted Bond

This paper presents an overview of the interconnection between various factors related to both cancer and type 2 diabetes mellitus (T2DM). Hyperglycemia, hyperinsulinemia, chronic inflammation, and obesity are involved in the development and progression of both diseases but, strong evidence for a direct causal relationship between diabetes and cancer, is lacking. Several studies described a relationship between hyperglycemia and cancer at the cellular, tissular and organismic levels but at the same time recent Mendelian randomization studies proved a significant causal relationship only between hyperglycemia and breast cancer. On the other hand, the association between both hyperinsulinemia and obesity and several cancer types appears to be robust as demonstrated by Mendelian randomized studies. Metabolic alterations, including the Warburg effect and excessive glucose consumption by tumors, are discussed, highlighting the potential impact of dietary restrictions, such as fasting and low-carb diets, on tumor growth and inflammation. Recent data indicates that circulating branched-chain amino acids levels, may represent novel biomarkers that may contribute to both better diabetes control and early pancreatic cancer detection. Understanding the underlying mechanisms and shared risk factors between cancer and T2DM can provide valuable insights for cancer prevention, early detection, and management strategies.

Effect of the ketone beta-hydroxybutyrate on markers of inflammation and immune function in adults with type 2 diabetes

Pre-clinical and cell culture evidence supports the role of the ketone beta-hydroxybutyrate (BHB) as an immunomodulatory molecule that may inhibit inflammatory signalling involved in several chronic diseases such as type 2 diabetes (T2D), but studies in humans are lacking. Therefore, we investigated the anti-inflammatory effect of BHB in humans across three clinical trials. To investigate if BHB suppressed pro-inflammatory cytokine secretion, we treated LPS-stimulated leukocytes from overnight-fasted adults at risk for T2D with BHB (Study 1). Next (Study 2), we investigated if exogenously raising BHB acutely in vivo by ketone monoester supplementation (KME) in adults with T2D would suppress pro-inflammatory plasma cytokines. In Study 3, we investigated the effect of BHB on inflammation via ex vivo treatment of LPS-stimulated leukocytes with BHB and in vivo thrice-daily pre-meal KME for 14 days in adults with T2D. Ex vivo treatment with BHB suppressed LPS-stimulated IL-1β, TNF-α, and IL-6 secretion and increased IL-1RA and IL-10 (Study 1). Plasma IL-10 increased by 90 min following ingestion of a single dose of KME in T2D, which corresponded to peak blood BHB (Study 2). Finally, 14 days of thrice-daily KME ingestion did not significantly alter plasma cytokines or leukocyte subsets including monocyte and T-cell polarization (Study 3). However, direct treatment of leukocytes with BHB modulated TNF-α, IL-1β, IFN-γ, and MCP-1 secretion in a time- and glucose-dependent manner (Study 3). Therefore, BHB appears to be anti-inflammatory in T2D, but this effect is transient and is modulated by the presence of disease, glycaemia, and exposure time.

Correlation between blood glucose level and poor wound healing after posterior lumbar interbody fusion in patients with type 2 diabetes

To investigate the correlation of blood glucose level with poor wound healing (PWH) after posterior lumbar interbody fusion (PLIF) in patients with type 2 diabetes (T2D). From January 2016 to January 2023, a case-control study was conducted to analyse the clinical data of 400 patients with T2D who were treated by PLIF and internal fixation at our hospital. The following data were recorded: gender; age; body mass index (BMI); surgical stage; average perioperative blood glucose level; perioperative blood glucose variance; perioperative blood glucose coefficient of variation; glycated haemoglobin level; preoperative levels of total protein, albumin and haemoglobin; postoperative levels of total protein, albumin and haemoglobin; surgical time; intraoperative bleeding volume; operator; postoperative drainage volume; and postoperative drainage tube removal time of each group. The indicators for monitoring blood glucose variability (GV) included the SD of blood glucose level (SDBG), coefficient of variation (CV) and maximum amplitude of variation (LAGE) before and after surgery. According to the diagnostic criteria for PWH, patients with postoperative PWH were determined and assigned to two groups: Group A (good wound healing group; n = 330 patients) and Group B (poor wound healing group; n = 70 patients). The preoperative and postoperative blood GV indicators, namely SDBG, CV and LAGE, were compared between these two groups. We also determined the relationship between perioperative blood GV parameters and PWH after PLIF surgery and its predictive value through correlation analysis and receiver-operating characteristic curve. Of the 400 enrolled patients, 70 patients had PWH. Univariate analysis revealed significant differences between the two groups in the course of diabetes, mean fasting blood glucose (MFBG), SDBG, CV, LAGE, preoperative hypoglycaemic program, surgical segment, postoperative drainage time, incision length and other factors (p < 0.05). However, no significant differences were noted in factors such as gender, age, body mass index, hypertension, coronary heart disease, admission fasting blood glucose, preoperative haemoglobin A1c, surgical time, intraoperative bleeding volume, intraoperative blood transfusion volume and postoperative drainage volume (p > 0.05). The area under the curve (AUC) values of preoperative SDBG, CV and LAGE were 0.6657, 0.6432 and 0.6584, respectively. The cut-off values were 1.13 mmol/L, 6.97% and 0.75 mmol/L, respectively. The AUC values for postoperative SDBG, CV and LAGE were 0.5885, 0.6255 and 0.6261, respectively. The cut-off values were 1.94 mmol/L, 24.32% and 2.75 mmol/L, respectively. The multivariate ridge regression analysis showed that preoperative MFBG, SDBG, CV and LAGE; postoperative SDBG, CV and LAGE; postoperative long drainage time; and multiple surgical segments were independent risk factors for T2D patients to develop surgical site infection after PLIF (p < 0.05). The perioperative blood GV in patients with T2D is closely related to the occurrence of PWH after PLIF. Reducing blood GV may help to reduce the occurrence of PWH after PLIF.

The Influence of Metabolism on Immune Response: A Journey to Understand Immunometabolism in the Context of Viral Infection

In recent years, the emergence of the concept of immunometabolism has shed light on the pivotal role that cellular metabolism plays in both the activation of immune cells and the development of immune programs. The antiviral response, a widely distributed defense mechanism used by infected cells, serves to not only control infections but also to attenuate their deleterious effects. The exploration of the role of metabolism in orchestrating the antiviral response represents a burgeoning area of research, especially considering the escalating incidence of viral outbreaks coupled with the increasing prevalence of metabolic diseases. Here, we present a review of current knowledge regarding immunometabolism and the antiviral response during viral infections. Initially, we delve into the concept of immunometabolism by examining its application in the field of cancer-a domain that has long spearheaded inquiries into this fascinating intersection of disciplines. Subsequently, we explore examples of immune cells whose activation is intricately regulated by metabolic processes. Progressing with a systematic and cellular approach, our aim is to unravel the potential role of metabolism in antiviral defense, placing significant emphasis on the innate and canonical interferon response.

Advancements of fish-derived peptides for mucormycosis: a novel strategy to treat diabetic compilation

Mucormycosis, an extremely fatal fungal infection, is a major hurdle in the treatment of diabetes consequences. The increasing prevalence and restricted treatment choices urge the investigation of novel therapeutic techniques. Because of their effective antimicrobial characteristics and varied modes of action, fish-derived peptides have lately emerged as viable options in the fight against mucormycosis. This review examines the potential further application of fish-derived peptides in diagnosing and managing mucormycosis in relation to diabetic complications. First, we examine the pathophysiology of mucormycosis and the difficulties in treating it in diabetics. We emphasize the critical need for alternative therapeutic methods for tackling the limitations of currently available antifungal medicines. The possibility of fish-derived peptides as an innovative approach to combat mucormycosis is then investigated. These peptides, derived from several fish species, provide wide antimicrobial properties against a variety of diseases. They also have distinct modes of action, such as rupture of cell membranes, suppression of development, and modification of the host immunological response. Furthermore, we investigate the problems and prospects connected with the clinical application of fish-derived peptides. Ultimately, future advances in fish-derived peptides, offer interesting avenues for the management of mucormycosis in the context of diabetic comorbidities. More research and clinical trials are needed to properly investigate these peptide's therapeutic potential and pave the way for their adoption into future antifungal therapies.

Staphylococcus aureus Adaptation to the Skin in Health and Persistent/Recurrent Infections

Staphylococcus aureus is a microorganism with an incredible capability to adapt to different niches within the human body. Approximately between 20 and 30% of the population is permanently but asymptomatically colonized with S. aureus in the nose, and another 30% may carry S. aureus intermittently. It has been established that nasal colonization is a risk factor for infection in other body sites, including mild to severe skin and soft tissue infections. The skin has distinct features that make it a hostile niche for many bacteria, therefore acting as a strong barrier against invading microorganisms. Healthy skin is desiccated; it has a low pH at the surface; the upper layer is constantly shed to remove attached bacteria; and several host antimicrobial peptides are produced. However, S. aureus is able to overcome these defenses and colonize this microenvironment. Moreover, this bacterium can very efficiently adapt to the stressors present in the skin under pathological conditions, as it occurs in patients with atopic dermatitis or suffering chronic wounds associated with diabetes. The focus of this manuscript is to revise the current knowledge concerning how S. aureus adapts to such diverse skin conditions causing persistent and recurrent infections.

Influenza Prevalence and Vaccine Efficacy among Diabetic Patients in Qatar

Seasonal influenza viruses may lead to severe illness and mortality in patients with comorbidities, including Diabetes Mellitus (DM). Vaccination against influenza in DM patients may reduce influenza incidence and severity. Before the emergence of the COVID-19 pandemic, influenza infections were the most prevalent respiratory infections in Qatar. Still, reports about influenza prevalence and vaccine efficacy in DM patients have not been reported. This study aimed to analyze influenza prevalence among other respiratory infections and assess influenza vaccine efficacy in DM patients in Qatar. Statistical analysis was performed on data obtained from Hamad Medical Corporation (HMC) database for patients that visited the emergency department (ED) with respiratory-like illnesses. The analysis was done for the period between January 2016 to December 2018. Among 17,525 patients who visited HMC-ED with clinical symptoms of respiratory infections, 2611(14.9%) were reported to have DM. Among DM patients, influenza was the most prevalent respiratory pathogen at 48.9%. Influenza virus A (IVA) was the most circulating type, contributing to 38.4%, followed by IVB contributing to 10.4% of total respiratory infections. Among the typed IVA-positive cases, 33.4% were H1N1, and 7.7% were H3N2. A significant decrease in influenza infections was reported in vaccinated DM patients (14.5%) when compared to non-vaccinated patients (18.9%) (p-value = 0.006). However, there was no significant relaxation in the clinical symptoms among vaccinated DM patients compared to their non-vaccinated counterparts. In conclusion, influenza was the most common etiology for respiratory viral infection among diabetic patients at the leading healthcare provider in Qatar. Although vaccination reduced the incidence rate among DM patients, it was less effective in preventing symptoms. Further studies on a larger cohort and for a more extended period are required to investigate influenza prevalence and vaccine efficacy among DM patients.

Epidemiological Features and Impact of High Glucose Level on Virulence Gene Expression and Serum Resistance of Klebsiella pneumoniae Causing Liver Abscess in Diabetic Patients

Purpose

Klebsiella pneumoniae (K. pneumoniae) is a Gram-negative bacterium that is predominantly associated with liver abscesses in global diabetic patients. High levels of glucose in the surrounding of K. pneumonia increase its pathogenicity including capsular polysaccharide (CPS) and fimbriae. Other important virulent factors include outer membrane protein A (ompA) and regulator mucoid phenotype A (rmpA). The objective of this investigation was to elucidate the effects of high glucose on rmpA and ompA gene expression and serum resistance of K. pneumoniae causing liver abscess.

Patients and Methods

The clinical history of 57 patients suffering from K. pneumoniae-caused liver abscesses (KLA) was acquired and their clinical and laboratory manifestations in the presence or absence of diabetes were analyzed. The antimicrobial susceptibility, serotypes, and virulence genes were tested. Clinical isolates of 3 serotype-K1 hypervirulent K. pneumoniae (hvKP) were used to detect the effect of exogenous high glucose on rmpA, ompA, and clbB genes expression, and bacterial serum resistance.

Results

KLA patients with diabetes showed higher C-reactive protein (CRP) compared to non-diabetic KLA patients. Furthermore, the diabetic group showed increased incidences of sepsis and invasive infections, and their length of hospital stay was also prolonged. Pre-incubation of K. pneumoniae in high glucose (0.5%) concentration up-regulated rmpA, ompA, and clbB genes expression. However, cAMP supplementation, which was inhibited by environmental glucose, reversed the increase of rmpA and ompA in a cAMP-dependent manner. Moreover, hvKP strains incubated in high glucose also exhibited enhanced protection from serum killing.

Conclusion

High glucose levels reflected by poor glycemic control has increased gene expression of rmpA and ompA in hvKP by the cAMP signaling pathway and enhanced its resistance to serum killing, thus providing a new and reasonable explanation for the high incidences of sepsis and invasive infections in KLA patients with diabetes.

SARS-CoV-2 infection and diabetes: Pathophysiological mechanism of multi-system organ failure

Since the discovery of the coronavirus disease 2019 outbreak, a vast majority of studies have been carried out that confirmed the worst outcome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in people with preexisting health conditions, including diabetes, obesity, hypertension, cancer, and cardiovascular diseases. Likewise, diabetes itself is one of the leading causes of global public health concerns that impose a heavy global burden on public health as well as socio-economic development. Both diabetes and SARS-CoV-2 infection have their independent ability to induce the pathogenesis and severity of multi-system organ failure, while the co-existence of these two culprits can accelerate the rate of disease progression and magnify the severity of the disease. However, the exact pathophysiology of multi-system organ failure in diabetic patients after SARS-CoV-2 infection is still obscure. This review summarized the organ-specific possible molecular mechanisms of SARS-CoV-2 and diabetes-induced pathophysiology of several diseases of multiple organs, including the lungs, heart, kidneys, brain, eyes, gastrointestinal system, and bones, and sub-sequent manifestation of multi-system organ failure.

Glucose supply and glycolysis inhibition shape the clinical fate of Staphylococcus epidermidis-infected preterm newborns

Preterm infants are susceptible to bloodstream infection by coagulase-negative staphylococci (CONS) that can lead to sepsis. High parenteral glucose supplement is commonly used to support their growth and energy expenditure, but may exceed endogenous regulation during infection, causing dysregulated immune response and clinical deterioration. Using a preterm piglet model of neonatal CONS sepsis induced by Staphylococcus epidermidis infection, we demonstrate the delicate interplay between immunity and glucose metabolism to regulate the host infection response. Circulating glucose levels, glycolysis and inflammatory response to infection are closely connected across the states of tolerance, resistance and immunoparalysis. Further, high parenteral glucose provision during infection induces hyperglycemia, elevated glycolysis and inflammation, leading to metabolic acidosis and sepsis, whereas glucose restricted individuals are clinically unaffected with increased gluconeogenesis to maintain moderate hypoglycemia. Finally, standard glucose supply maintaining normoglycemia or pharmacological glycolysis inhibition enhances bacterial clearance and dampens inflammation but fails to prevent sepsis. Our results uncover how blood glucose and glycolysis controls circulating immune responses, in turn determining the clinical fate of CONS infected preterm individuals. This questions the current practice of parenteral glucose supply for preterm infants during infection.

Diabetes Mellitus and Dental Implants: A Systematic Review and Meta-Analysis

The present review aimed to evaluate the impact of diabetes mellitus on dental implant failure rates and marginal bone loss (MBL). An electronic search was undertaken in three databases, plus a manual search of journals. Meta-analyses were performed as well as meta-regressions in order to verify how the odds ratio (OR) and MBL were associated with follow-up time. The review included 89 publications. Altogether, there were 5510 and 62,780 implants placed in diabetic and non-diabetic patients, respectively. Pairwise meta-analysis showed that implants in diabetic patients had a higher failure risk in comparison to non-diabetic patients (OR 1.777, p < 0.001). Implant failures were more likely to occur in type 1 diabetes patients than in type 2 (OR 4.477, p = 0.032). The difference in implant failure between the groups was statistically significant in the maxilla but not in the mandible. The MBL mean difference (MD) between the groups was 0.776 mm (p = 0.027), with an estimated increase of 0.032 mm in the MBL MD between groups for every additional month of follow-up (p < 0.001). There was an estimated decrease of 0.007 in OR for every additional month of follow-up (p = 0.048). In conclusion, implants in diabetic patients showed a 77.7% higher risk of failure than in non-diabetic patients.

A Machine-Generated View of the Role of Blood Glucose Levels in the Severity of COVID-19

SARS-CoV-2 started spreading toward the end of 2019 causing COVID-19, a disease that reached pandemic proportions among the human population within months. The reasons for the spectrum of differences in the severity of the disease across the population, and in particular why the disease affects more severely the aging population and those with specific preconditions are unclear. We developed machine learning models to mine 240,000 scientific articles openly accessible in the CORD-19 database, and constructed knowledge graphs to synthesize the extracted information and navigate the collective knowledge in an attempt to search for a potential common underlying reason for disease severity. The machine-driven framework we developed repeatedly pointed to elevated blood glucose as a key facilitator in the progression of COVID-19. Indeed, when we systematically retraced the steps of the SARS-CoV-2 infection, we found evidence linking elevated glucose to each major step of the life-cycle of the virus, progression of the disease, and presentation of symptoms. Specifically, elevations of glucose provide ideal conditions for the virus to evade and weaken the first level of the immune defense system in the lungs, gain access to deep alveolar cells, bind to the ACE2 receptor and enter the pulmonary cells, accelerate replication of the virus within cells increasing cell death and inducing an pulmonary inflammatory response, which overwhelms an already weakened innate immune system to trigger an avalanche of systemic infections, inflammation and cell damage, a cytokine storm and thrombotic events. We tested the feasibility of the hypothesis by manually reviewing the literature referenced by the machine-generated synthesis, reconstructing atomistically the virus at the surface of the pulmonary airways, and performing quantitative computational modeling of the effects of glucose levels on the infection process. We conclude that elevation in glucose levels can facilitate the progression of the disease through multiple mechanisms and can explain much of the differences in disease severity seen across the population. The study provides diagnostic considerations, new areas of research and potential treatments, and cautions on treatment strategies and critical care conditions that induce elevations in blood glucose levels.

Peptide inhibition of neutrophil-mediated injury after in vivo challenge with supernatant of Pseudomonas aeruginosa and immune-complexes

Neutrophils are recognized for their role in host defense against pathogens as well as inflammatory conditions mediated through many mechanisms including neutrophil extracellular trap (NET) formation and generation of reactive oxygen species (ROS). NETs are increasingly appreciated as a major contributor in autoimmune and inflammatory diseases such as cystic fibrosis. Myeloperoxidase (MPO), a key neutrophil granule enzyme mediates generation of hypochlorous acid which, when extracellular, can cause host tissue damage. To better understand the role played by neutrophils in inflammatory diseases, we measured and modulated myeloperoxidase activity and NETs in vivo, utilizing a rat peritonitis model. RLS-0071 is a 15 amino acid peptide that has been shown to inhibit myeloperoxidase activity and NET formation in vitro. The rat model of inflammatory peritonitis was induced with intraperitoneal injection of either P. aeruginosa supernatant or immune-complexes. After euthanasia, a peritoneal wash was performed and measured for myeloperoxidase activity and free DNA as a surrogate for measurement of NETs. P. aeruginosa supernatant caused a 2-fold increase in MPO activity and free DNA when injected IP. Immune-complexes injected IP increased myeloperoxidase activity and free DNA 2- fold. RLS-0071 injection decreased myeloperoxidase activity and NETs in the peritoneal fluid generally to baseline levels in the presence of P. aeruginosa supernatant or immune-complexes. Taken together, RLS-0071 demonstrated the ability to inhibit myeloperoxidase activity and NET formation in vivo when initiated by different inflammatory stimuli including shed or secreted bacterial constituents as well as immune-complexes.

Uncontrolled diabetes mellitus increases risk of infection in patients with advanced cirrhosis

BACKGROUND

Diabetes mellitus (DM) is common in patients with cirrhosis and is associated with increased risk of infection.

AIM

To analyze the impact of uncontrolled DM on infection and mortality among inpatients with advanced cirrhosis.

METHODS

This study utilized the Nationwide Inpatient Sample from 1998 to 2014. We defined advanced cirrhosis using a validated ICD-9-CM algorithm requiring a diagnosis of cirrhosis and clinically significant portal hypertension or decompensation. The primary outcome was bacterial infection. Secondary outcomes included inpatient mortality stratified by elderly age (age≥70). Multivariable logistic regression analyzed outcomes.

RESULTS

906,559 (29.2%) patients had DM and 109,694 (12.1%) were uncontrolled. Patients who had uncontrolled DM were younger, had less ascites, but more encephalopathy. Bacterial infection prevalence was more common in uncontrolled DM (34.2% vs. 28.4%, OR 1.33, 95% CI 1.29-1.37, p<0.001). Although uncontrolled DM was not associated with mortality, when stratified by age, elderly patients with uncontrolled DM had a significantly higher risk of inpatient mortality (OR 1.62, 95% CI 1.46-1.81).

CONCLUSIONS

Uncontrolled DM is associated with increased risk of infection, and when combined with elderly age is associated with increased risk of inpatient mortality. Glycemic control is a modifiable target to improve morbidity and mortality in patients with advanced cirrhosis.

Adaptation of Staphylococcus aureus in a Medium Mimicking a Diabetic Foot Environment

Staphylococcus aureus is the most prevalent pathogen isolated from diabetic foot infections (DFIs). The purpose of this study was to evaluate its behavior in an in vitro model mimicking the conditions encountered in DFI. Four clinical S. aureus strains were cultivated for 16 weeks in a specific environment based on the wound-like medium biofilm model. The adaptation of isolates was evaluated as follows: by Caenorhabditis elegans model (to evaluate virulence); by quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) (to evaluate expression of the main virulence genes); and by Biofilm Ring test^® (to assess the biofilm formation). After 16 weeks, the four S. aureus had adapted their metabolism, with the development of small colony variants and the loss of β-hemolysin expression. The in vivo nematode model suggested a decrease of virulence, confirmed by qRT-PCRs, showing a significant decrease of expression of the main staphylococcal virulence genes tested, notably the toxin-encoding genes. An increased expression of genes involved in adhesion and biofilm was noted. Our data based on an in vitro model confirm the impact of environment on the adaptation switch of S. aureus to prolonged stress environmental conditions. These results contribute to explore and characterize the virulence of S. aureus in chronic wounds.

Epidemiology and the Estimated Burden of Microbial Keratitis on the Health Care System in Taiwan: A 14-Year Population-Based Study

PURPOSE

To investigate the epidemiologic characteristics of microbial keratitis and its overall burden on the health care system in Taiwan.

DESIGN

Retrospective, population-based study.

METHODS

We conducted a study using claims data in the Taiwan National Health Insurance Research Database in 2000-2013, employing diagnoses, drugs, and procedure codes to define diseases and procedures. Participants were classified into groups according to the requirement of hospitalization and surgical intervention. The main outcome measures were incidence, risk factors, predictive factors for hospitalization and surgical intervention, and health care expenditure.

RESULTS

A total of 2,071 patients were included. The overall incidence significantly increased from 8.4 in 2000 to 20.2 per 100,000 person-years in 2013. The peak age range of incidence was between 18 and 40 years, but the peak age group for health care expenditures was those older than 65 years. A total of 704 patients (33.99%) had analyzable risk factors, of which the top 3 were diabetes mellitus (DM, 11.52%), eye trauma (10.55%), and dry eye (8.72%). Older patients, those using steroid and antiglaucoma agents, and those with ocular and systemic diseases were susceptible to further hospitalization and surgical intervention for the treatment of microbial keratitis.

CONCLUSIONS

In Taiwan, DM, eye trauma, and dry eye were key predisposing factors for microbial keratitis. Older patients (>40 years) accounted for approximately 80% of health care expenditure for the management of infectious keratitis. Special care may be required for older patients with medication-related risk factors and ocular and systemic comorbidities because they are likely to have severe diseases leading to hospitalization and surgical interventions.

Angiotensin-converting enzyme 2, the complement system, the kallikrein-kinin system, type-2 diabetes, interleukin-6, and their interactions regarding the complex COVID-19 pathophysiological crossroads

Because of the current COVID-19-pandemic, the world is currently being held hostage in various lockdowns. ACE2 facilitates SARS-CoV-2 cell-entry, and is at the very center of several pathophysiological pathways regarding the RAAS, CS, KKS, T2DM, and IL-6. Their interactions with severe COVID-19 complications (e.g. ARDS and thrombosis), and potential therapeutic targets for pharmacological intervention, will be reviewed.

Glucose transport in lymphocytes

Glucose uptake into lymphocytes is accomplished by non-concentrative glucose carriers of the GLUT family (GLUT1, GLUT3, GLUT4, GLUT6) and/or by the Na⁺-coupled glucose carrier SGLT1. The latter accumulates glucose against glucose gradients and is still effective at very low extracellular glucose concentrations. Signaling involved in SGLT1 expression and activity includes protein kinase A (PKA), protein kinase C (PKC), serum- and glucocorticoid-inducible kinase (SGK1), AMP-activated kinase (AMPK), and Janus kinases (JAK2 and JAK3). Glucose taken up is partially stored as glycogen. In hypoxic environments, such as in tumors as well as infected and inflamed tissues, lymphocytes depend on energy production from glycogen-dependent glycolysis. The lack of SGLT1 may compromise glycogen storage and thus lymphocyte survival and function in hypoxic tissues. Accordingly, in mice, genetic knockout of sglt1 compromised bacterial clearance following Listeria monocytogenes infection leading to an invariably lethal course of the disease. Whether the effect was due to the lack of sglt1 in lymphocytes or in other cell types still remains to be determined. Clearly, additional experimental effort is required to define the role of glucose transport by GLUTs and particularly by SGLT1 for lymphocyte survival and function, as well as orchestration of the host defense against tumors and bacterial infections.

Type 2 Diabetes and its Impact on the Immune System

INTRODUCTION

Type 2 Diabetes (T2D) is a major health problem worldwide. This metabolic disease is indicated by high blood glucose levels due to insufficient insulin production by the pancreas. An inflammatory response occurs as a result of the immune response to high blood glucose levels as well as the presence of inflammatory mediators produced by adipocytes and macrophages in fat tissue. This low and chronic inflammation damages the pancreatic beta cells and leads to insufficient insulin production, which results in hyperglycemia. Hyperglycemia in diabetes is thought to cause dysfunction of the immune response, which fails to control the spread of invading pathogens in diabetic subjects. Therefore, diabetic subjects are known to more susceptible to infections. The increased prevalence of T2D will increase the incidence of infectious diseases and related comorbidities.

OBJECTIVE

This review provides an overview of the immunological aspect of T2D and the possible mechanisms that result in increased infections in diabetics.

CONCLUSION

A better understanding of how immune dysfunctions occur during hyperglycemia can lead to novel treatments and preventions for infectious diseases and T2D comorbidities, thus improving the outcome of infectious disease treatment in T2D patients.

Cytokine and Adhesion Molecule Expression Induced by Different Strains of Staphylococcus aureus in Type 1 Diabetic Rats: Role of Insulin

Introduction: Staphylococcus aureus may provoke peritonitis and death, especially in immunocompromized individuals such as diabetic patients. We evaluated the role of insulin in S. aureus-induced peritoneal infection in diabetic and non-diabetic rats. Materials/Methods: Alloxan-diabetic male Wistar rats and their respective controls received intraperitoneal injections of different strains of S. aureus or sterile phosphate-buffered saline. After 3 days of infection, the first set of diabetic and non-diabetic rats received 4 and 1 IU, respectively, of neutral protamine Hagedorn insulin and were analyzed 8 h later. The second set of diabetic and non-diabetic rats received 4 and 1 IU, respectively, of insulin 2 h before intraperitoneal infection and a half dose of insulin at 5 p.m. for the next 2 days and were analyzed 16 h later. The following measurements were performed: (a) number of cells in the peritoneal lavage fluid (PeLF), white blood cell count, and blood glucose; (b) serum insulin and corticosterone; (c) cytokine levels in the PeLF; (d) expression of adhesion molecules in the vascular endothelium; and (e) microbicidal activity. Results: Diabetic rats showed an increased number of polymorphonuclear leukocytes (PMNs) and increased concentrations of CINC-1, IL-4, and IFN-γ in the PeLF after infection with the ATCC 25923 or N315 αHL⁺ strain. The mesenteric expression of PECAM-1 was increased after infection with the N315 HLA⁺ strain. ICAM-1 expression was increased with ATCC infection. Treatment of diabetic rats with a single dose of insulin restored CINC-1 levels in the PeLF for both strains; however, PMN migration, IL-4, and IFN-γ were restored in rats infected with the ATCC strain, whereas the PeLF concentrations of CINC-2, IL-1β, and IL-4 were increased in N315-infected animals. Insulin restored PMN migration and CINC-2 levels in the PeLF in ATCC-infected rats. After multiple treatments with insulin, the levels of IL-1β, IL-6, and IFN-γ were increased in the PeLF of diabetic rats after infection with either strain, and CINC-2 levels were restored in N315-infected animals. Conclusion: These results suggest that insulin distinctively modulates cytokine production or release, PMN leukocyte migration, and adhesion molecule expression during the course of peritonitis induced by different strains of S. aureus.

Low prevalence of rheumatoid arthritis among patients with pre-existing type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a non-autoimmune disease characterized by chronic hyperglycemia and increased non-enzymatic glycation of amino groups. Glycation occurs through a series of events eventually leading to the formation of irreversible "advanced glycation end-products" (AGEs). AGEs may affect the function of long-lived proteins, including cytokines, immunoglobulins and their receptors, resulting in a "less active" immune system. We aimed to test the hypothesis that a common inflammatory chronic disease, such as rheumatoid arthritis (RA), in which the earliest event is an inflammatory response to unknown stimulus, has a lower prevalence in these patients than in normoglycemic, non-diabetic subjects.

METHODS

In this study, we compared the prevalence of RA in a prospectively followed outpatient cohort of patients with T2DM patients (n=1,630) with a control, matched, non-diabetic population (n=1,630).

RESULTS

Among non-diabetic controls, 13 patients (prevalence 0.80%) with RA were identified. An almost 3-fold lower prevalence of RA (0.25%) was found in consecutive patients with T2DM (P=0.029). Most of the RA cases among participants with T2DM were diagnosed early after diabetes onset. The onset of RA in patients with T2DM occurred at significantly older age (64±15 years) as compared to the non-diabetes group (48±18 years; P=0.004).

CONCLUSIONS

The prevalence of RA is lower and occurs in an older age in patients with pre-existing T2DM in comparison with people without T2DM.

Hyperglycemia during first-line R-CHOP or dose adjusted R-EPOCH chemotherapy for non-Hodgkin lymphoma is prevalent and associated with chemotherapy alteration - a retrospective study

High-dose glucocorticoids such as prednisone are combined with cytotoxic chemotherapy in the R-CHOP or dose adjusted R-EPOCH regimens used for non-Hodgkin lymphoma (NHL). In this retrospective study, our primary objective was to evaluate the incidence of hyperglycemia during first-line R-CHOP or DA-EPOCH-R. The secondary objectives were to evaluate the incidence of chemotherapy alteration and overall survival in those with and without hyperglycemia. One hundred and sixty patients were eligible. We found that 47% of all patients had at least one hyperglycemic episode and hyperglycemia was associated with chemotherapy alteration (p = .028). Multivariate analysis revealed international prognostic index (IPI) ≥ 3 (p = .045) and chemotherapy alteration (p = .001) were associated with decreased overall survival. We conclude that hyperglycemia is common during first-line NHL treatment with R-CHOP or DA-EPOCH-R, even in the absence of known diabetes and is associated with alterations of chemotherapy. Baseline pre-PET scan fasting blood glucose of 100 mg/dL or higher may predict hyperglycemia during therapy.

Association between glycaemic control and common infections in people with Type 2 diabetes: a cohort study

AIM

To investigate the impact of glycaemic control on infection incidence in people with Type 2 diabetes.

METHODS

We compared infection rates during 2014 in people with Type 2 diabetes and people without diabetes in a large primary care cohort in the UK (the Royal College of General Practitioners Research and Surveillance Centre database). We performed multilevel logistic regression to investigate the impact of Type 2 diabetes on presentation with infection, and the effect of glycaemic control on presentation with upper respiratory tract infections, bronchitis, influenza-like illness, pneumonia, intestinal infectious diseases, herpes simplex, skin and soft tissue infections, urinary tract infections, and genital and perineal infections. People with Type 2 diabetes were stratified by good [HbA_1c < 53 mmol/mol (< 7%)], moderate [HbA_1c 53-69 mmol/mol (7-8.5%)] and poor [HbA_1c > 69 mmol/mol (> 8.5%)] glycaemic control using their most recent HbA_1c concentration. Infection incidence was adjusted for important sociodemographic factors and patient comorbidities.

RESULTS

We identified 34 278 people with Type 2 diabetes and 613 052 people without diabetes for comparison. The incidence of infections was higher in people with Type 2 diabetes for all infections except herpes simplex. Worsening glycaemic control was associated with increased incidence of bronchitis, pneumonia, skin and soft tissue infections, urinary tract infections, and genital and perineal infections, but not with upper respiratory tract infections, influenza-like illness, intestinal infectious diseases or herpes simplex.

CONCLUSIONS

Almost all infections analysed were more common in people with Type 2 diabetes. Infections that are most commonly of bacterial, fungal or yeast origin were more frequent in people with worse glycaemic control.

Complement Activation and STAT4 Expression Are Associated with Early Inflammation in Diabetic Wounds

Diabetic non-healing wounds are a major clinical problem. The mechanisms leading to poor wound healing in diabetes are multifactorial but unresolved inflammation may be a major contributing factor. The complement system (CS) is the most potent inflammatory cascade in humans and contributes to poor wound healing in animal models. Signal transducer and activator of transcription 4 (STAT4) is a transcription factor expressed in immune and adipose cells and contributes to upregulation of some inflammatory chemokines and cytokines. Persistent CS and STAT4 expression in diabetic wounds may thus contribute to chronic inflammation and delayed healing. The purpose of this study was to characterize CS and STAT4 in early diabetic wounds using db/db mice as a diabetic skin wound model. The CS was found to be activated early in the diabetic wounds as demonstrated by increased anaphylatoxin C5a in wound fluid and C3-fragment deposition by immunostaining. These changes were associated with a 76% increase in nucleated cells in the wounds of db/db mice vs.

CONTROLS

The novel classical CS inhibitor, Peptide Inhibitor of Complement C1 (PIC1) reduced inflammation when added directly or saturated in an acellular skin scaffold, as reflected by reduced CS components and leukocyte infiltration. A significant increase in expression of STAT4 and the downstream macrophage chemokine CCL2 and its receptor CCR2 were also found in the early wounds of db/db mice compared to non-diabetic controls. These studies provide evidence for two new promising targets to reduce unresolved inflammation and to improve healing of diabetic skin wounds.

An Alteration of Lymphocytes Subpopulations and Immunoglobulins Levels in Patients with Diabetic Foot Ulcers Infected Particularly by Resistant Pathogens

The aim of our study was to analyse immune abnormalities in patients with chronic infected diabetic foot ulcers (DFUs) especially those infected by resistant microorganisms. Methods. 68 patients treated in our foot clinic for infected chronic DFUs with 34 matched diabetic controls were studied. Patients with infected DFUs were subdivided into two subgroups according to the antibiotic sensitivity of causal pathogen: subgroup S infected by sensitive (n = 50) and subgroup R by resistant pathogens (n = 18). Selected immunological markers were compared between the study groups and subgroups. Results. Patients with infected chronic DFUs had, in comparison with diabetic controls, significantly reduced percentages (p < 0.01) and total numbers of lymphocytes (p < 0.001) involving B lymphocytes (p < 0.01), CD4+ (p < 0.01), and CD8+ T cells (p < 0.01) and their naive and memory effector cells. Higher levels of IgG (p < 0.05) including IgG1 (p < 0.001) and IgG3 (p < 0.05) were found in patients with DFUs compared to diabetic controls. Serum levels of immunoglobulin subclasses IgG2 and IgG3 correlated negatively with metabolic control (p < 0.05). A trend towards an increased frequency of IgG2 deficiency was found in patients with DFUs compared to diabetic controls (22% versus 15%; NS). Subgroup R revealed lower levels of immunoglobulins, especially of IgG4 (p < 0.01) in contrast to patients infected by sensitive bacteria. The innate immunity did not differ significantly between the study groups. Conclusion. Our study showed changes mainly in the adaptive immune system represented by low levels of lymphocyte subpopulations and their memory effector cells, and also changes in humoral immunity in patients with DFUs, even those infected by resistant pathogens, in comparison with diabetic controls.

The Effect of Short-Term Hyperglycemia on the Innate Immune System

BACKGROUND

Diabetes mellitus increases the susceptibility to infection by altering both the innate and the adaptive immune systems. Hyperglycemia has been associated with adverse outcomes in hospitalized patients, especially critically ill patients; these poor outcomes are explained in part by hospital-associated infections.

MATERIALS AND METHODS

PubMed, EMBASE and Google Scholar were searched to identify studies published between 1970 and 2014 reporting short-term effects of hyperglycemia on the innate immune system. MeSH database search terms included hyperglycemia, immune system, inflammation, inflammation mediators, neutrophils, endothelial dysfunction, complement system proteins and diabetes. Pertinent articles reported studies in healthy volunteers and diabetic patients, using in vitro laboratory experiments, and with animal models.

RESULTS

Hyperglycemia activates protein kinase C, and this inhibits neutrophil migration, phagocytosis, superoxide production and microbial killing. High glucose concentrations decrease the formation of neutrophil extracellular traps. Hyperglycemia can also induce Toll-like receptor expression and inhibit neutrophil function and apoptosis. High glucose concentrations decrease vascular dilation and increase permeability during the initial inflammatory responses, possibly through protein kinase C activation. Hyperglycemia can cause direct glycosylation of proteins and alter the tertiary structure of complement; these changes inhibit immunoglobulin-mediated opsonization of bacteria and complement fixation to bacteria and decreases phagocytosis. Hyperglycemia also stimulates the production and release of cytokines. Several trials have demonstrated that better glycemic control reduces nosocomial infections in critically ill patients and surgical site infections.

CONCLUSIONS

In summary, acute hyperglycemia can significantly alter innate immune responses to infection, and this potentially explains some of the poor outcomes in hospitalized patients who develop hyperglycemia.

Serum levels of immunoglobulins in an adult population and their relationship with type 2 diabetes

OBJECTIVE

Some studies have found patients with diabetes had an impaired humoral immune response. Immunoglobulins provide key information on the humoral immune status. But few population-based studies comprehensively estimated the serum immunoglobulins concentration in type 2 diabetes (T2D). So we design a cross-sectional study to investigate the relationships between immunoglobulin levels and prevalence of T2D in a large-scale adult population.

METHODS

A cross-sectional assessment was performed in 10,691 participants living in Tianjin, China. Type 2 diabetes was defined in accordance with the criteria of the world health organization, and serum levels of immunoglobulins were determined by the immunonephelometric technique. Adjusted logistic models were used to assess relationships between the quintiles of immunoglobulins concentration and the prevalence of T2D.

RESULTS

In this study, the prevalence of T2D was 11.7%, and the means (standard deviation) of immunoglobulins (IgG, IgE, IgM, IgA) were 1192.3 (241.1)mg/dL, 92.3 (234.6)IU/mL, 104.8 (55.8)mg/dL, 234.1 (96.2)mg/dL, respectively. The adjusted odds ratio (95% confidence interval) of T2D for the highest immunoglobulins (IgG, IgE, IgM, IgA) quintile, when compared to the lowest quintile were 0.64 (0.52, 0.78), 1.00 (0.81, 1.22), 0.77 (0.62, 0.95) and 1.57 (1.29, 1.92), respectively.

CONCLUSIONS

Decreased IgG and IgM, and increased IgA levels were independently related to the prevalence of T2D among the adult population. Our findings indicate that the immunoglobulins might useful predictive factors for T2D in the general adult population. Further studies are needed to explore the causality and exact mechanisms of immunoglobulins in T2D.