Tissue resident macrophages: Key players in the pathogenesis of type 2 diabetes and its complications

Evolution and global research trends of immunity in diabetic nephropathy: a bibliometric and visual analysis from 2004 to 2023

BACKGROUND

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease, with an increasing prevalence worldwide, but its pathomechanisms remain incompletely understood. Accumulating evidence suggests that immunity plays an important role in the development of DN. Many papers have been published in the field over the last 20 years, but there has been no bibliometric review of the research hotspots and trends in the field. This study aimed to assess the current research status and future trends of the link between immune and DN using bibliometric analysis.

METHODS

Publications on the association between immunity and DN from 2004 to 2023 were retrieved from the Web of Science Core Collection database and screened according to inclusion criteria. VOSviewer and CiteSpace software were employed to visualize research trends and hotspots in the field. Data including author, institution, country, journal, reference, and keyword were analyzed.

RESULTS

Ultimately 1246 publications meeting the criteria were included in the bibliometric analysis, involving 838 articles (84.96%) and 408 reviews (15.04%). The literature covered 81 countries and regions, 1751 institutions, and 6584 authors. The top 2 countries in terms of the number of publications were China (435) and the United States (318), and they collaborated most frequently. The United States had the highest number of citations for published papers (18,161), far exceeding the other countries. England had 38 publications but had the highest average number of citations (92.32). The University of California system was the most prolific institution (25 papers, 1062 citations, 42.48 citations per paper). Frontiers in Immunology was the most prolific journal in the field (30 papers). The most cited journal was Kidney International (863 citations). The analysis of keywords and references showed that inflammation, ferroptosis, and lipid metabolism may be future research hotspots in this field.

CONCLUSIONS

The number of publications related to immunity and DN has increased annually over the past 20 years, with a significant increase in the last 3 years especially. Our results identified research hotspots and trends in the field. These findings provide valuable perspectives for future research, enhancing our understanding of the immune-related mechanisms of DN and exploring potential therapeutic strategies.

Macrophage based drug delivery: Key challenges and strategies

As a natural immune cell and antigen presenting cell, macrophages have been studied and engineered to treat human diseases. Macrophages are well-suited for use as drug carriers because of their biological characteristics, such as excellent biocompatibility, long circulation, intrinsic inflammatory homing and phagocytosis. Meanwhile, macrophages' uniquely high plasticity and easy re-education polarization facilitates their use as part of efficacious therapeutics for the treatment of inflammatory diseases or tumors. Although recent studies have demonstrated promising advances in macrophage-based drug delivery, several challenges currently hinder further improvement of therapeutic effect and clinical application. This article focuses on the main challenges of utilizing macrophage-based drug delivery, from the selection of macrophage sources, drug loading, and maintenance of macrophage phenotypes, to drug migration and release at target sites. In addition, corresponding strategies and insights related to these challenges are described. Finally, we also provide perspective on shortcomings on the road to clinical translation and production.

New insights into the pathogenesis of SARS-CoV-2 during and after the COVID-19 pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the respiratory distress condition known as COVID-19. This disease broadly affects several physiological systems, including the gastrointestinal, renal, and central nervous (CNS) systems, significantly influencing the patient's overall quality of life. Additionally, numerous risk factors have been suggested, including gender, body weight, age, metabolic status, renal health, preexisting cardiomyopathies, and inflammatory conditions. Despite advances in understanding the genome and pathophysiological ramifications of COVID-19, its precise origins remain elusive. SARS-CoV-2 interacts with a receptor-binding domain within angiotensin-converting enzyme 2 (ACE2). This receptor is expressed in various organs of different species, including humans, with different abundance. Although COVID-19 has multiorgan manifestations, the main pathologies occur in the lung, including pulmonary fibrosis, respiratory failure, pulmonary embolism, and secondary bacterial pneumonia. In the post-COVID-19 period, different sequelae may occur, which may have various causes, including the direct action of the virus, alteration of the immune response, and metabolic alterations during infection, among others. Recognizing the serious adverse health effects associated with COVID-19, it becomes imperative to comprehensively elucidate and discuss the existing evidence surrounding this viral infection, including those related to the pathophysiological effects of the disease and the subsequent consequences. This review aims to contribute to a comprehensive understanding of the impact of COVID-19 and its long-term effects on human health.

Effects of resveratrol on the anthropometric indices and inflammatory markers: an umbrella meta-analysis

BACKGROUND

The evidence for resveratrol's anti-obesity and anti-inflammatory qualities is accumulating, though meta-analyses have reported mixed results. The current umbrella meta-analysis aimed to assess the present evidence and provide an accurate estimate of the overall effects of resveratrol on the anthropometric indices and inflammatory markers.

METHOD

The Web of Science, PubMed, Scopus, and Google Scholar databases were searched till March 2023. The meta-analysis was performed utilizing a random-effects model. Moreover, the overall strength and quality of the evidence were assessed using the GRADE tool.

RESULTS

The results from 19 meta-analyses investigating 81 unique randomized controlled trials with 4088 participants revealed that resveratrol supplementation reduced the body mass index (ES =  - 0.119, 95% CI (- 0.192, - 0.047), p = 0.001), waist circumference (ES =  - 0.405, 95% CI [- 0.664, - 0.147], p = 0.002), serum levels of C-reactive protein (ES =  - 0.390, 95% CI [- 0.474, - 0.306], p < 0.001), and tumor necrosis factor-α (ES =  - 0.455, 95% CI [- 0.592, - 0.318], p < 0.001) in comparison to the control group. The effects of resveratrol on body weight and Interleukin-6 levels of participants were not significant. However, resveratrol administration significantly decreased body weight in trials with intervention duration ≥ 12 weeks [ES =  - 0.160, 95% CI (- 0.268, - 0.052)] and supplement dosage ≥ 500 mg/day [ES =  - 0.130, 95% CI (- 0.238, - 0.022)].

CONCLUSION

The findings suggest the beneficial effects of resveratrol supplementation on reducing general and central obesity, as well as decreasing some inflammatory markers. Nevertheless, further high-quality research is required to prove these achievements and also evaluate resveratrol's effects on other inflammatory markers.

The Pivotal Role of Macrophages in the Pathogenesis of Pancreatic Diseases

The pancreas is an organ with both exocrine and endocrine functions, comprising a highly organized and complex tissue microenvironment composed of diverse cellular and non-cellular components. The impairment of microenvironmental homeostasis, mediated by the dysregulation of cell-to-cell crosstalk, can lead to pancreatic diseases such as pancreatitis, diabetes, and pancreatic cancer. Macrophages, key immune effector cells, can dynamically modulate their polarization status between pro-inflammatory (M1) and anti-inflammatory (M2) modes, critically influencing the homeostasis of the pancreatic microenvironment and thus playing a pivotal role in the pathogenesis of the pancreatic disease. This review aims to summarize current findings and provide detailed mechanistic insights into how alterations mediated by macrophage polarization contribute to the pathogenesis of pancreatic disorders. By analyzing current research comprehensively, this article endeavors to deepen our mechanistic understanding of regulatory molecules that affect macrophage polarity and the intricate crosstalk that regulates pancreatic function within the microenvironment, thereby facilitating the development of innovative therapeutic strategies that target perturbations in the pancreatic microenvironment.

Clotrimazole reverses macrophage M2 polarization by disrupting the PI3K/AKT/mTOR pathway

Macrophages switch among different activation phenotypes according to distinct environmental stimuli, varying from pro-inflammatory (M1) to alternative (also named resolutive; M2) activation forms. M1-and M2-activated macrophages represent the two extremes of the activation spectrum involving multiple species, which vary in terms of function and the cytokines secreted. The consensus is that molecular characterization of the distinct macrophage population and the signals driving their activation will help in explaining disease etiology and formulating therapies. For instance, myeloid cells residing in the tumor microenvironment are key players in tumor progression and usually display an M2-like phenotype, which help tumor cells to evade local inflammatory processes. Therefore, these specific cells have been proposed as targets for tumor therapies by changing their activation profile. Furthermore, M2 polarized macrophages are phagocytic cells promoting tissue repair and wound healing and are therefore potential targets to treat different diseases. We have already shown that clotrimazole (CTZ) decreases tumor cell viability and thus tumor growth. The mechanism by which CTZ exerts its effects remains to be determined, but this drug is an inhibitor of the PI3K/AKT/mTOR pathway. In this study, we show that CTZ downregulated M2-activation markers in macrophages polarized to the M2 profile. This effect occurred without interfering with the expression of M1-polarized markers or pro-inflammatory cytokines and signaling. Moreover, CTZ suppressed NFkB pathway intermediates and disrupted PI3K/AKT/mTOR signaling. We concluded that CTZ reverses macrophage M2 polarization by disrupting the PI3K/AKT/mTOR pathway, which results in the suppression of NFkB induction of M2 polarization. In addition, we find that CTZ represents a promising therapeutic tool as an antitumor agent.

Combination therapy of metformin and morin attenuates insulin resistance, inflammation, and oxidative stress in skeletal muscle of high-fat diet-fed mice

Lipid accumulation, inflammation, and oxidative stress are the most important causes of muscle insulin resistance. The aim of this study was to investigate the single and combined treatment effects of metformin (MET) and morin (MOR) on lipid accumulation, inflammation, and oxidative stress in the skeletal muscle of mice fed a high-fat diet. The mice were supplemented with MET (230 mg/kg diet), MOR (100 mg/kg diet), and MET + MOR for 9 weeks. Our results revealed that single treatment with MET or MOR, and with a stronger effect of MET + MOR combined treatment, reduced body weight gain, improved glucose intolerance and enhanced Akt phosphorylation in the muscle tissue. In addition, plasma and muscle triglyceride levels were decreased after treatment with MET and MOR. The expression of genes involved in macrophage infiltration and polarization and pro-inflammatory cytokines showed that MET + MOR combined treatment, significantly reduced inflammation in the muscle. Furthermore, combined treatment of MET + MOR with greater efficacy than the single treatment improved several oxidative stress markers in the muscle. Importantly, combined treatment of MET and MOR could increase the expression of nuclear factor erythroid 2-related factor 2, the master regulator of the antioxidant response. These findings suggest that combination of MET with MOR might ameliorate insulin resistance, inflammation, and oxidative stress in the skeletal muscle of mice fed high-fat diet.

Lower odds of COVID-19-related mortality in hospitalised patients with type II diabetes mellitus: A single-centre study

BACKGROUND

COVID-19 infection in patients with type 2 diabetes mellitus (T2DM) -a chronic illness in Lebanon-is not well described.

METHODS

This was a single-centre retrospective observational study of 491 patients, including 152 patients with T2DM, who were hospitalised for COVID-19 between 20 August 2020 and 21 April 2021. Data on clinical characteristics, laboratory and radiological findings and outcomes were collected from the electronic medical records. Clinical characteristics and in-hospital mortality between patients with and without T2DM infected with COVID-19 using multivariate analysis were compared.

RESULTS

Patients with T2DM were significantly older than those without T2DM (mean age, 68.7 vs. 60.3 years). Patients with T2DM were more likely to present with a body temperature of <38.3°C (83.9% vs. 69.9%) and less likely to present with chest pain (3.9% vs. 9.1%) and sore throat (2.0% vs. 6.8%). Patients with T2DM were more likely to be hypertensive (76.35% vs. 41%) and dyslipidaemic (58.6% vs. 25.7%) and had more frequent underlying coronary artery disease (33.6% vs. 12.4%). The rates of patients with creatinine levels of ≥1.17 mg/L and troponin T levels of ≥4 ng/dL were higher in the T2DM group than in the non-T2DM group (30.4% vs. 15% and 93.3% vs. 83.1%, respectively). Patients with T2DM were more likely to be admitted to the intensive care unit (ICU) (34.2% vs. 22.1%), require invasive ventilation (18.4% vs. 10.3%) and receive vasopressors (16.4% vs. 10.0%). Increasing age and the use of invasive ventilation and vasopressors were associated with higher odds of mortality (odds ratio (OR), 1.08, 9.95 and 19.83, respectively), whereas longer ICU stay was associated with lower odds of mortality (OR, 0.38). The odds of mortality were lower in the T2DM group than in the non-T2DM group (OR, 0.27).

CONCLUSION

Among patients hospitalised for COVID-19, those with T2DM were older, presented with milder symptoms and had more comorbidities and higher troponin T levels compared with those without T2DM. Despite the worse clinical course, the patients with T2DM had lower odds of mortality than those without T2DM.

Resveratrol as a potential protective compound against skeletal muscle insulin resistance

The increasing prevalence of type 2 diabetes has become a major global problem. Insulin resistance has a central role in pathophysiology of type 2 diabetes. Skeletal muscle is responsible for the disposal of most of the glucose under conditions of insulin stimulation, and insulin resistance in skeletal muscle causes dysregulation of glucose homeostasis in the whole body. Despite the current pharmaceutical and non-pharmacological treatment strategies to combat diabetes, there is still a need for new therapeutic agents due to the limitations of the therapeutic agents. Meanwhile, plant polyphenols have attracted the attention of researchers for their use in the treatment of diabetes and have gained popularity. Resveratrol, a stilbenoid polyphenol, exists in various plant sources, and a growing body of evidence suggests its beneficial properties, including antidiabetic activities. The present review aimed to provide a summary of the role of resveratrol in insulin resistance in skeletal muscle and its related mechanisms. To achieve the objectives, by searching the PubMed, Scopus and Web of Science databases, we have summarized the results of all cell culture, animal, and human studies that have investigated the effects of resveratrol in different models on insulin resistance in skeletal muscle.

AGEs-RAGE-KCa3.1 pathway mediates palmitic acid-induced migration of PBMCs from patients with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is characterized by chronic low-grade systemic inflammation. Tissue infiltration by monocyte migration contributes to the pathogenesis of vascular complications in T2DM. We studied the role of intermediate-conductance Ca²⁺-activated K⁺ (K_Ca3.1) channels in the palmitic acid (PA)-induced migration of peripheral blood mononuclear cells (PBMCs) from T2DM patients and the influence of advanced glycation endproducts (AGEs). A total of 49 T2DM patients and 33 healthy subjects was recruited into this study. Using flow cytometry and Western blotting analysis as well as cell migration assay, we found that there was a significant decrease in frequency of T lymphocytes and monocytes in CD45⁺ leukocyte population. PA at 100 μM stimulated migration of PBMCs from T2DM individuals, which was inhibited by the specific K_Ca3.1 channel blocker TRAM-34 (1 μM). The PBMC migration was positively correlated with glycosylated hemoglobin A1 chain (HbA1c) level of T2DM patients, an indicator of AGEs, and PBMCs with higher level of HbA1c showed upregulated expression of toll-like receptor (TLR) 2/4 and K_Ca3.1 channels. In THP-1 cells, AGEs at 200 μg/ml increased protein expression of TLR 2/4 and K_Ca3.1 channels, and were synergistically involved in PA-induced migration through receptors of AGEs (RAGE)-mediated K_Ca3.1 upregulation. In conclusion, in PBMCs of T2DM patients, AGEs promotes PA-induced migration via upregulation of TLR2/4 and K_Ca3.1 channels.

Metformin-chlorogenic acid combination reduces skeletal muscle inflammation in c57BL/6 mice on high-fat diets

BACKGROUND

Inflammation at the low-grade level has been found to contribute to obesity-induced insulin resistance in the skeletal muscle (SM). This study investigated the anti-inflammatory potential of metformin (MET) combined with chlorogenic acid (CGA) in SM of mice fed a high-fat diet (HFD).

MATERIALS AND METHODS

The C57BL/6 mice were divided into five groups of ten each, normal diet, HFD, HFD + MET, HFD + CGA and HFD + MET + CGA.

RESULTS

The results revealed that MET and CGA, alone or in combination, have a reducing effect on weight gain, plasma triglyceride, glucose and insulin levels. MET in combination with CGA led to attenuation of SM inflammation, an effect that was associated with decreasing macrophages infiltration rate. Combined treatment of MET and CGA also resulted in switching macrophages from M1 to M2 phenotype, presented by the higher expression levels of arginase and CD206 (M2 markers) and lower expression levels of iNOS and cd11c markers (M1). In addition, combination treatment was more effective in increasing the anti-inflammatory cytokines expression (IL-10) and decreasing the expression of pro-inflammatory mediators (TNF-α, IL-1β, MCP-1 and IL-6).

CONCLUSION

These findings suggest that the combination treatment of MET and CGA is likely to be a promising approach to control SM inflammation in the HFD-fed model.

Multivalent mannose-conjugated siRNA causes robust gene silencing in pancreatic macrophages in vivo

Nucleic acid therapeutics have been utilized for gene regulation, and their recent advancement has led to approval of novel drugs for liver-related disorders. However, systemic extrahepatic delivery remains challenging. Here, we report newly designed mannose-conjugated oligonucleotides for delivering oligonucleotides to macrophages by leveraging the mannose receptor, C-type 1 (MRC1, CD206), which is abundantly expressed in macrophages. We investigated the relationship between cellular uptake and multivalency (mono to tetra) of mannose ligands or linker length and selected a trivalent-mannose ligand. Trivalent-mannose (Man3)-conjugated siRNA induced concentration-dependent gene silencing in both human CD206-overexpressing cells and human macrophages in vitro. After subcutaneous injection into mice, we observed a high distribution of Man3-conjugated oligonucleotides in the liver and pancreata as well as cellular uptake into Kupffer cells and pancreatic macrophages. A single subcutaneous injection of Man3-conjugated siRNA (10 mg/kg) targeting β₂-microglobulin (B2M) silenced B2m mRNA expression by ∼50% and decreased its protein levels in mouse pancreatic macrophages compared to those in saline-treated mice. Of note, multiple subcutaneous injections decreased B2m gene expression and B2M protein levels by ∼80% and ∼85%, respectively. These results show that mannose-conjugation with oligonucleotides is expected to help deliver oligonucleotides to macrophages and regulate gene expression in vivo, particularly in the pancreas.

Exercise-induced responses in matrix metalloproteinases and osteopontin are not moderated by exercise format in males with overweight or obesity

PURPOSE

Matrix metalloproteinase-2 (MMP-2) and -3 (MMP-3), and osteopontin (OPN) are associated with adipose-tissue expansion and development of metabolic disease. The purpose of the current study was to assess the circulating concentration of these markers, along with adiponectin and glucose concentrations, in response to acute exercise in individuals with overweight or obesity.

METHODS

Fourteen sedentary males with overweight or obesity (29.0 ± 3.1 kg/m²) completed two separate, 3-day trials in randomised and counterbalanced order. An oral glucose tolerance test (OGTT) was performed on each day of the trial. Day two of each trial consisted of a single 30 min workload-matched bout of either high-intensity interval exercise (HIIE; alternating 100% and 50% of peak pulmonary oxygen uptake, [Formula: see text]O_2peak) or continuous moderate intensity (CME; 60% [Formula: see text]O_2peak) cycling completed 1 h prior to the OGTT. Glucose and physical activity were continuously monitored, while MMP-2, MMP-3, OPN and adiponectin were measured pre-, 0 h post-, 1 h post- and 25 h post-exercise.

RESULTS

Exercise transiently increased MMP-3 and decreased OPN (both p < 0.01), but not MMP-2 or adiponectin. There were no differences in the response of inflammatory markers to the different exercise formats. Exercise increased mean daily glucose concentration and area under the glucose curve during the OGTT on Day 2 and Day 3 (main effect of time; p < 0.05).

CONCLUSION

Acute cycling exercise decreased OPN, which is consistent with longer term improvements in cardiometabolic health and increased MMP-3, which is consistent with its role in tissue remodelling. Interestingly, exercise performed prior to the morning OGTT augmented the glucose concentrations in males.

TRIAL REGISTRATION

ACTRN12613001086752.

Functional Potassium Channels in Macrophages

Macrophages are the predominant component of innate immunity, which is an important protective barrier of our body. Macrophages are present in all organs and tissues of the body, their main functions include immune surveillance, bacterial killing, tissue remodeling and repair, and clearance of cell debris. In addition, macrophages can present antigens to T cells and facilitate inflammatory response by releasing cytokines. Macrophages are of high concern due to their crucial roles in multiple physiological processes. In recent years, new advances are emerging after great efforts have been made to explore the mechanisms of macrophage activation. Ion channel is a class of multimeric transmembrane protein that allows specific ions to go through cell membrane. The flow of ions through ion channel between inside and outside of cell membrane is required for maintaining cell morphology and intracellular signal transduction. Expressions of various ion channels in macrophages have been detected. The roles of ion channels in macrophage activation are gradually caught attention. K⁺ channels are the most studied channels in immune system. However, very few of published papers reviewed the studies of K⁺ channels on macrophages. Here, we will review the four types of K⁺ channels that are expressed in macrophages: voltage-gated K⁺ channel, calcium-activated K⁺ channel, inwardly rectifying K⁺ channel and two-pore domain K⁺ channel.

Effects of propofol on macrophage activation and function in diseases

Macrophages work with monocytes and dendritic cells to form a monocyte immune system, which constitutes a powerful cornerstone of the immune system with their powerful antigen presentation and phagocytosis. Macrophages play an essential role in infection, inflammation, tumors and other pathological conditions, but these cells also have non-immune functions, such as regulating lipid metabolism and maintaining homeostasis. Propofol is a commonly used intravenous anesthetic in the clinic. Propofol has sedative, hypnotic, anti-inflammatory and anti-oxidation effects, and it participates in the body’s immunity. The regulation of propofol on immune cells, especially macrophages, has a profound effect on the occurrence and development of human diseases. We summarized the effects of propofol on macrophage migration, recruitment, differentiation, polarization, and pyroptosis, and the regulation of these propofol-regulated macrophage functions in inflammation, infection, tumor, and organ reperfusion injury. The influence of propofol on pathology and prognosis via macrophage regulation is also discussed. A better understanding of the effects of propofol on macrophage activation and function in human diseases will provide a new strategy for the application of clinical narcotic drugs and the treatment of diseases.

Anti-inflammatory effects of resveratrol in patients with cardiovascular disease: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Chronic inflammation is one of the most important factors involved in the development and progression of cardiovascular disease (CVDs). Accumulating evidence has described the effect of resveratrol, a natural polyphenolic compound, on biomarkers of inflammation among patients with CVDs; however, findings are controversial. Here we performed a systematic review and meta-analysis of randomized controlled trials to evaluate the effect of resveratrol supplements on TNF-α, IL-6, and CRP levels in CVDs patients.

METHODS

Online research was conducted in the following database: MEDLINE, EMBASE, Cochrane Library, Web of Science databases, and Scopus. This systematic review and meta-analysis were conducted to investigate the effects of resveratrol supplements on inflammatory biomarkers among patients with CVDs. The meta-analysis was performed using Comprehensive Meta-Analysis (CMA) V3 software.

RESULTS

Six RCTs met the inclusion criteria and were selected for the current meta-analysis. Our results demonstrated that resveratrol significantly decreases serum levels of CRP (MD= -0.63, 95% CI: -0.1.13, -0.12; p = 0.01), and TNF-α (MD= -0.55, 95% CI: -1.04, -0.06; p = 0.02), however, resveratrol had not significant effect on serum concentration of IL-6 (MD= -0.12, 95% CI: -0.52, 0.27; p = 0.53), in patients with CVDs.

CONCLUSION

Our results suggest that resveratrol can be used as a potential treatment in patients with CVD by reducing inflammatory conditions.

The impact of sensory neuropathy and inflammation on epithelial wound healing in diabetic corneas

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes, with several underlying pathophysiological mechanisms, some of which are still uncertain. The cornea is an avascular tissue and sensitive to hyperglycemia, resulting in several diabetic corneal complications including delayed epithelial wound healing, recurrent erosions, neuropathy, loss of sensitivity, and tear film changes. The manifestation of DPN in the cornea is referred to as diabetic neurotrophic keratopathy (DNK). Recent studies have revealed that disturbed epithelial-neural-immune cell interactions are a major cause of DNK. The epithelium is supplied by a dense network of sensory nerve endings and dendritic cell processes, and it secretes growth/neurotrophic factors and cytokines to nourish these neighboring cells. In turn, sensory nerve endings release neuropeptides to suppress inflammation and promote epithelial wound healing, while resident immune cells provide neurotrophic and growth factors to support neuronal and epithelial cells, respectively. Diabetes greatly perturbs these interdependencies, resulting in suppressed epithelial proliferation, sensory neuropathy, and a decreased density of dendritic cells. Clinically, this results in a markedly delayed wound healing and impaired sensory nerve regeneration in response to insult and injury. Current treatments for DPN and DNK largely focus on managing the severe complications of the disease. Cell-based therapies hold promise for providing more effective treatment for diabetic keratopathy and corneal ulcers.

The Roles of Adipose Tissue Macrophages in Human Disease

Macrophages are a population of immune cells functioning in antigen presentation and inflammatory response. Research has demonstrated that macrophages belong to a cell lineage with strong plasticity and heterogeneity and can be polarized into different phenotypes under different microenvironments or stimuli. Many macrophages can be recruited by various cytokines secreted by adipose tissue. The recruited macrophages further secrete various inflammatory factors to act on adipocytes, and the interaction between the two leads to chronic inflammation. Previous studies have indicated that adipose tissue macrophages (ATMs) are closely related to metabolic diseases like obesity and diabetes. Here, we will not only conclude the current progress of factors affecting the polarization of adipose tissue macrophages but also elucidate the relationship between ATMs and human diseases. Furthermore, we will highlight its potential in preventing and treating metabolic diseases as immunotherapy targets.

Alternative polarization of resident macrophages improves hyperglycemia-associated male infertility

Recent studies have demonstrated that hyperglycemia induces inflammation in male reproductive system to cause sperm damages and infertility, which may be associated with re-polarization of tissue macrophages from an anti-inflammation M2-like subtype to a pro-inflammation M1-like subtype. However, the underlying mechanisms are not fully determined and a practical approach to interfere with the progression of infertility is lacking. Here, we transduced the testicular macrophages back to the M2-like phenotype with adeno-associated viruses carrying an M2-trigger, Jumonji domain-containing protein D3 (JMJD3), under a macrophage-specific CD68 promoter (CD68p-JMJD3), in streptozotocin-induced diabetic mice. We found that JMJD3-induced M2-polarization of testicular macrophages significantly improved the mating capability of diabetic male mice. The diabetes-induced impairment of the motility of spermatozoa and the decreases in the serum and testicular testosterone levels were both significantly alleviated in CD68p-JMJD3-treated diabetic mice. Thus, our study proposes a practical strategy to treat hyperglycemia-associated infertility.

Donor Heterogeneity in the Human Macrophage Response to a Biomaterial under Hyperglycemia in vitro

Macrophages have a commanding role in scaffold-driven in situ tissue regeneration. Depending on their polarization state, macrophages mediate the formation and remodeling of new tissue by secreting growth factors and cytokines. Therefore, successful outcomes of material-driven in situ tissue vascular tissue engineering depends largely on the immuno-regenerative potential of the recipient. A large cohort of patients requiring vascular replacements suffers from systemic multifactorial diseases, like diabetes, which gives rise to a hyperglycemic and aggressive oxidative inflammatory environment that is hypothesized to hamper a well-balanced regenerative process. Here, we aimed to fundamentally explore the effects of hyperglycemia, as one of the hallmarks of diabetes, on the macrophage response to 3D electrospun synthetic biomaterials for in situ tissue engineering, in terms of inflammatory profile and tissue regenerative capacity. To simulate the early phases of the in situ regenerative cascade, we used a bottom-up in vitro approach. Primary human macrophages (n=8 donors) and (myo)fibroblasts in mono- or co-culture were seeded in 2D, as well as in a 3D electrospun resorbable polycaprolactone bisurea (PCL-BU) scaffold and exposed to normoglycemic (5.5 mM glucose), hyperglycemic (25 mM glucose) and osmotic control conditions (5.5 mM glucose, 19.5 mM mannitol). The results showed that macrophage polarization by biochemical stimuli was effective under all glycemic conditions and that the polarization states dictated expression of the receptors SCL2A1 (glucose transporter 1) and CD36 (fatty acid transporter). In 3D, the macrophage response to hyperglycemic conditions was strongly donor-dependent in terms of phenotype, cytokine secretion profile, and metabolic receptor expression. When co-cultured with (myo)fibroblasts, hyperglycemic conditions led to an increased expression of fibrogenic markers (ACTA2, COL1, COL3, IL-1β). Together, these findings show that the hyperglycemic and hyperosmotic conditions may indeed influence the process of macrophage-driven in situ tissue engineering, and that the extent of this is likely to be patient-specific.

Chicoric acid does not restore palmitate-induced decrease in irisin levels in PBMCs of newly diagnosed patients with T2D and healthy subjects

Targeting irisin as a myokine/adipokine is a new therapeutic approach in the improvement of insulin-resistance (IR) during type 2 diabetes (T2D). In present study we evaluated the effects of palmitate and chicoric acid (CA) on irisin production in peripheral blood mononuclear cells (PBMCs) of patients with T2D. This study performed on 20 newly diagnosed patients with T2D and 20 healthy subjects. PBMCs treated with palmitate and CA. PPARGC1A and FNDC5 genes expression assessed using qRT-PCR. Irisin levels in cell culture medium measured by ELISA. Palmitate decreased PPARGC1A and FNDC5 genes expression, as well as irisin levels in PBMCs from T2D and healthy volunteers. CA significantly restored palmitate-induced decrease in PPARGC1A gene expression in PBMCs of healthy subjects. Although, FNDC5 gene expression and irisin levels were not induced significantly by CA. In conclusion, palmitate decreases irisin production through down-regulation of PPARGC1A and FNDC5 expressions. However, CA does not effect on irisin pathway.Key pointsPalmitate reduced PPARGC1A and FNDC5 genes expression, as well as irisin secretion in PBMCs.Palmitate-induced decrease in PPARGC1A gene expression significantly has been reversed by CA in PBMCs of healthy subjects.CA did not return palmitate-decreased in FNDC5 gene expression and irisin levels in PBMCs.

Interactions between NLRP3 inflammasome and glycolysis in macrophages: New insights into chronic inflammation pathogenesis

NLRP3 inflammasome activation in macrophages fuels sterile inflammation, which has been tied with metabolic reprogramming characterized by high glycolysis and low oxidative phosphorylation. The key enzymes in glycolysis and glycolysis‐related products can regulate and activate NLRP3 inflammasome. In turn, NLRP3 inflammasome is considered to affect glycolysis, as well. However, the exact mechanism remains ambiguous. On the basis of these findings, the focus of this review is mainly on the developments in our understanding of interaction between NLRP3 inflammasome activation and glycolysis in macrophages, and small molecule compounds that influence the activation of NLRP3 inflammasomes by regulating glycolysis in macrophages. The application of this interaction in the treatment of diseases is also discussed. This paper may yield valuable clues for development of novel therapeutic agent for NLRP3 inflammasome‐related diseases.

Research progress on the mechanism by which skin macrophage dysfunction mediates chronic inflammatory injury in diabetic skin

Macrophages, the main immune cells in the skin, form an innate immune barrier. Under physiological conditions, skin maintains immune barrier function through macrophage phagocytosis and antigen presentation. Parenchymal and stromal cell regeneration plays an important role in skin injury repair and uses macrophage plasticity to influence and stabilize the skin microenvironment. Diabetic skin lesions are the most common diabetes complication and are involved in the early pathophysiology of diabetic foot. Therefore, studying the initial link in diabetic skin lesions is a research hot spot in the early pathogenesis of diabetic foot. Skin inflammation caused by hyperglycaemia, oxidative stress and other injuries is an important feature, but the specific mechanism is unknown. Recent studies have suggested that chronic inflammatory injury is widely involved in a variety of skin diseases, and whether it plays an important role in diabetic skin lesions is unclear. In this review, current research hotspots were combined with the pathogenesis of diabetic skin lesions and analysed from the perspectives of the physiological function of skin macrophages, the impairment of skin macrophages in diabetes, and the mechanism of chronic inflammatory injury in macrophages to provide a theoretical basis for early screening and evaluation of diabetic foot.

Mechanistic investigations of diabetic ocular surface diseases

With the global prevalence of diabetes mellitus over recent decades, more patients suffered from various diabetic complications, including diabetic ocular surface diseases that may seriously affect the quality of life and even vision sight. The major diabetic ocular surface diseases include diabetic keratopathy and dry eye. Diabetic keratopathy is characterized with the delayed corneal epithelial wound healing, reduced corneal nerve density, decreased corneal sensation and feeling of burning or dryness. Diabetic dry eye is manifested as the reduction of tear secretion accompanied with the ocular discomfort. The early clinical symptoms include dry eye and corneal nerve degeneration, suggesting the early diagnosis should be focused on the examination of confocal microscopy and dry eye symptoms. The pathogenesis of diabetic keratopathy involves the accumulation of advanced glycation end-products, impaired neurotrophic innervations and limbal stem cell function, and dysregulated growth factor signaling, and inflammation alterations. Diabetic dry eye may be associated with the abnormal mitochondrial metabolism of lacrimal gland caused by the overactivation of sympathetic nervous system. Considering the important roles of the dense innervations in the homeostatic maintenance of cornea and lacrimal gland, further studies on the neuroepithelial and neuroimmune interactions will reveal the predominant pathogenic mechanisms and develop the targeting intervention strategies of diabetic ocular surface complications.

Poor prognosis indicators of type-2 diabetic COVID-19 patients

Diabetes is associated with a worse prognosis and a high risk of morbidity and mortality in COVID-19 patients. We aimed to evaluate the main factors involved in the poor prognosis in diabetic patients. A total of 984 patients diagnosed with COVID-19 admitted to the hospital were included in this study. Patients were first divided into type-2 diabetic (DM+) and non-diabetic (DM–) groups. The participants were analyzed based on the National Early Warning Score (NEWS) and on the Quick-Sequential Organ Failure Assessment (qSOFA) to find the best prognostic risk score for our study. The DM+ and DM– groups were divided into non-severe and severe groups. Comparative and correlative analyses were used to identify the physiological parameters that could be employed for creating a potential risk indicator for DM+ COVID-19 patients. We found a poorer prognosis for the DM+ COVID-19 patients with a higher ICU admission rate, mechanical ventilation rate, vasopressor use, dialysis, and longer treatment times compared with the DM– group. DM+ COVID-19 patients had increased plasma glucose, lactate, age, urea, NEWS, and D-dimer levels, herein referred to as the GLAUND set, and worse prognosis and outcomes when compared with infected DM– patients. The NEWS score was a better indicator for assessing COVID-19 severity in diabetic patients than the q-SOFA score. In conclusion, diabetic COVID-19 patients should be assessed with the NEWS score and GLAUND set for determining their prognosis COVID-19 prognosis.

Review: Roles of human serum albumin in prediction, diagnoses and treatment of COVID-19

The severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) keeps on destroying normal social integrity worldwide, bringing about extraordinary medical services, cultural and financial interruption. Individuals with diabetes have been demonstrated to be at higher risk of complications and even death when exposed to SARS-CoV-2. Regardless of pandemic scale infection, there is presently limited comprehension on the potential impact of SARS-CoV-2 on individuals with diabetes. Human serum albumin (HSA) is the most abundant circulating plasma protein in human serum and attracted more interest from researchers because most susceptible to non-enzymatic glycation reactions. Albumin down-regulates the expression of ACE2 that is the target receptor of COVID-19. Hypoalbuminemia, coagulopathy, and vascular disease have been connected in COVID-19 and appear to predict outcomes independent of age and morbidity. This review discusses the most recent evidence that the ACE/ACE2 ratio could influence by human serum albumin both the susceptibility of individuals to SARS-CoV-2 infection and the outcome of the COVID-19 disease.

Diabetes in COVID-19 patients: challenges and possible management strategies

Background

The recent pandemic of coronavirus disease 19 (COVID-19) has been causing intense stress among the global population. In the case of hospitalized and ICU-admitted COVID-19 patients with comorbidities, it has been observed that a major portion of them are diabetic. Therefore, researchers had indicated a link between diabetes mellitus (DM) and COVID-19. Furthermore, DM is a potential risk factor for the severity of COVID-19 cases. Thus, in this study, the correlation existing between diabetic patients and COVID-19 was summarized.

Main body of the abstract

Diabetic patients have a weaker immune system, less viral clearance rate, malfunctions of metabolic activity due to their high blood glucose level, and other associated problems. This does not increase the susceptibility for the patients to be infected with COVID-19. However, the severity of COVID-19 can worsen due to the comorbidity of DM.

Short conclusion

Proper management, appropriate use of drugs that do not increase the ACE2 expression, lowering blood glucose level, decreasing the susceptibility of SARS-CoV-2, and maintaining a healthy lifestyle could be effective.

Insight of the role of mitochondrial calcium homeostasis in hepatic insulin resistance

Due to the rapid rise in the prevalence of chronic metabolic disease, more and more clinicians and basic medical researchers focus their eyesight on insulin resistance (IR), an early and central event of metabolic diseases. The occurrence and development of IR are primarily caused by excessive energy intake and reduced energy consumption. Liver is the central organ that controls glucose homeostasis, playing a considerable role in systemic IR. Decreased capacity of oxidative metabolism and mitochondrial dysfunction are being blamed as the direct reason for the development of IR. Mitochondrial Ca²⁺ plays a fundamental role in maintaining proper mitochondrial function and redox stability. The maintaining of mitochondrial Ca²⁺ homeostasis requires the cooperation of ion channels in the inner and outer membrane of mitochondria, such as mitochondrial calcium uniporter complex (MCUC) and voltage-dependent anion channels (VDACs). In addition, the crosstalk between the endoplasmic reticulum (ER), lysosome and plasma membrane with mitochondria is also significant for mitochondrial calcium homeostasis, which is responsible for an efficient network of cellular Ca²⁺ signaling. Here, we review the recent progression in the research about the regulation factors for mitochondrial Ca²⁺ and how the dysregulation of mitochondrial Ca²⁺ homeostasis is involved in the pathogenesis of hepatic IR, providing a new perspective for further exploring the role of ion in the onset and development of IR.

Dyslipidemia, Diabetes and Atherosclerosis: Role of Inflammation and ROS-Redox-Sensitive Factors

The prevalence of diabetes is growing at an alarming rate with increased disability, morbidity, and often premature mortality because of the various complications of this disorder. Chronic hyperglycemia, dyslipidemia, and other metabolic alterations lead to the development and progression of macro- and microvascular complications of diabetes including cardiovascular, retinal and kidney disease. Despite advances in glucose and lipid lowering treatments, a large number of diabetic individuals develop one or more types of these complications, ultimately leading to end-organ damage over the time. Atherosclerosis is the major macro-vascular complications of diabetes and the primary underlying cause of cardiovascular disease (CVD) posing heavy burden on the health care system. In this review, we discuss the involvement of dyslipidemia in the progression of atherosclerosis by activating the pro-inflammatory cytokines and oxidative stress-related factors. In addition, we also provide information on various pharmacological agents that provides protection against diabetic atherosclerosis by reducing inflammation and oxidative stress.

Immuno-regenerative biomaterials for in situ cardiovascular tissue engineering - Do patient characteristics warrant precision engineering?

In situ tissue engineering using bioresorbable material implants - or scaffolds - that harness the patient's immune response while guiding neotissue formation at the site of implantation is emerging as a novel therapy to regenerate human tissues. For the cardiovascular system, the use of such implants, like blood vessels and heart valves, is gradually entering the stage of clinical translation. This opens up the question if and to what extent patient characteristics influence tissue outcomes, necessitating the precision engineering of scaffolds to guide patient-specific neo-tissue formation. Because of the current scarcity of human in vivo data, herein we review and evaluate in vitro and preclinical investigations to predict the potential role of patient-specific parameters like sex, age, ethnicity, hemodynamics, and a multifactorial disease profile, with special emphasis on their contribution to the inflammation-driven processes of in situ tissue engineering. We conclude that patient-specific conditions have a strong impact on key aspects of in situ cardiovascular tissue engineering, including inflammation, hemodynamic conditions, scaffold resorption, and tissue remodeling capacity, suggesting that a tailored approach may be required to engineer immuno-regenerative biomaterials for safe and predictive clinical applicability.

Cross-linked hyaluronic acid slows down collagen membrane resorption in diabetic rats through reducing the number of macrophages

OBJECTIVES

We previously showed that accelerated degradation of collagen membranes (CMs) in diabetic rats is associated with increased infiltration of macrophages and blood vessels. Since pre-implantation immersion of CMs in cross-linked high molecular weight hyaluronic acid (CLHA) delays membrane degradation, we evaluated here its effect on the number of macrophages and endothelial cells (ECs) within the CM as a possible mechanism for inhibition of CM resorption.

MATERIALS AND METHODS

Diabetes was induced with streptozotocin in 16 rats, while 16 healthy rats served as control. CM discs were labeled with biotin, soaked in CLHA or PBS, and implanted under the scalp. Fourteen days later, CMs were embedded in paraffin and the number of macrophages and ECs within the CMs was determined using antibodies against CD68 and transglutaminase II, respectively.

RESULTS

Diabetes increased the number of macrophages and ECs within the CMs (∼2.5-fold and fourfold, respectively). Immersion of CMs in CLHA statistically significantly reduced the number of macrophages (p < 0.0001) in diabetic rats, but not that of ECs. In the healthy group, CLHA had no significant effect on the number of either cells. Higher residual collagen area and membrane thickness in CLHA-treated CMs in diabetic animals were significantly correlated with reduced number of macrophages but not ECs.

CONCLUSIONS

Immersion of CM in CLHA inhibits macrophage infiltration and reduces CM degradation in diabetic animals.

CLINICAL RELEVANCE

The combination of CLHA and CM may represent a valuable approach when guided tissue regeneration or guided bone regeneration procedures are performed in diabetic patients.

Macrophage as a Peripheral Pain Regulator

A neuroimmune crosstalk is involved in somatic and visceral pathological pain including inflammatory and neuropathic components. Apart from microglia essential for spinal and supraspinal pain processing, the interaction of bone marrow-derived infiltrating macrophages and/or tissue-resident macrophages with the primary afferent neurons regulates pain signals in the peripheral tissue. Recent studies have uncovered previously unknown characteristics of tissue-resident macrophages, such as their origins and association with regulation of pain signals. Peripheral nerve macrophages and intestinal resident macrophages, in addition to adult monocyte-derived infiltrating macrophages, secrete a variety of mediators, such as tumor necrosis factor-α, interleukin (IL)-1β, IL-6, high mobility group box 1 and bone morphogenic protein 2 (BMP2), that regulate the excitability of the primary afferents. Neuron-derived mediators including neuropeptides, ATP and macrophage-colony stimulating factor regulate the activity or polarization of diverse macrophages. Thus, macrophages have multitasks in homeostatic conditions and participate in somatic and visceral pathological pain by interacting with neurons.

Diabetes Mellitus and Its Metabolic Complications: The Role of Adipose Tissues

Many approaches have been used in the effective management of type 2 diabetes mellitus. A recent paradigm shift has focused on the role of adipose tissues in the development and treatment of the disease. Brown adipose tissues (BAT) and white adipose tissues (WAT) are the two main types of adipose tissues with beige subsets more recently identified. They play key roles in communication and insulin sensitivity. However, WAT has been shown to contribute significantly to endocrine function. WAT produces hormones and cytokines, collectively called adipocytokines, such as leptin and adiponectin. These adipocytokines have been proven to vary in conditions, such as metabolic dysfunction, type 2 diabetes, or inflammation. The regulation of fat storage, energy metabolism, satiety, and insulin release are all features of adipose tissues. As such, they are indicators that may provide insights on the development of metabolic dysfunction or type 2 diabetes and can be considered routes for therapeutic considerations. The essential roles of adipocytokines vis-a-vis satiety, appetite, regulation of fat storage and energy, glucose tolerance, and insulin release, solidifies adipose tissue role in the development and pathogenesis of diabetes mellitus and the complications associated with the disease.

Total Glucosides of Paeony Ameliorate Pristane-Induced Lupus Nephritis by Inducing PD-1 ligands+ Macrophages via Activating IL-4/STAT6/PD-L2 Signaling

Macrophages, a major subset of innate immune cells, are main infiltrating cells in the kidney in lupus nephritis. Macrophages with different phenotypes exert diverse or even opposite effects on the development of lupus nephritis. Substantial evidence has shown that macrophage M2 polarization is beneficial to individuals with chronic kidney disease. Further, it has been reported that PD-1 ligands (PD-Ls) contribute to M2 polarization of macrophages and their immunosuppressive effects. Total glucosides of paeony (TGP), originally extracted from Radix Paeoniae Alba, has been approved in China to treat some autoimmune diseases. Here, we investigated the potentially therapeutic effects of TGP on lupus nephritis in a pristane-induced murine model and explored the molecular mechanisms regulating macrophage phenotypes. We found that TGP treatment significantly improved renal function by decreasing the urinary protein and serum creatinine, reducing serum anti-ds-DNA level and ameliorating renal immunopathology. TGP increased the frequency of splenic and peritoneal F4/80⁺CD11b⁺CD206⁺ M2-like macrophages with no any significant effect on F4/80⁺CD11b⁺CD86⁺ M1-like macrophages. Immunofluorescence double-stainings of the renal tissue showed that TGP treatment increased the frequency of F4/80⁺Arg1⁺ subset while decreasing the percentage of F4/80⁺iNOS⁺ subset. Importantly, TGP treatment increased the percentage of both F4/80⁺CD11b⁺PD-L1⁺ and F4/80⁺CD11b⁺PD-L2⁺ subsets in spleen and peritoneal lavage fluid as well as the kidney. Furthermore, TGP augmented the expressions of CD206, PD-L2 and phosphorylated STAT6 in IL-4-treated Raw264.7 macrophages in vitro while its effects on PD-L2 were abolished by pretreatment of the cells with an inhibitor of STAT6, AS1517499. However, TGP treatment did not affect the expressions of STAT1 and PD-L1 in Raw264.7 macrophages treated with LPS/IFN-γ in vitro, indicating a possibly indirect effect of TGP on PD-L1 expression on macrophages in vivo. Thus, for the first time, we demonstrated that TGP may be a potent drug to treat lupus nephritis by inducing F4/80⁺CD11b⁺CD206⁺ and F4/80⁺CD11b⁺PD-L2⁺ macrophages through IL-4/STAT6/PD-L2 signaling pathway.

The role of macrophage polarization and function in environmental toxicant-induced cancers

Macrophages are a critical member of the innate immune system and can intensify tumor invasiveness and assist the growth of neoplastic cells. Moreover, they have the capability to reinforce immunosuppression and angiogenesis. Various investigations suggest that health-related issues, including inflammatory disorders and neoplastic diseases may be caused by environmental toxicant exposure. However, it is still unclear what role these environmental toxicants play in causing carcinogenesis by disturbing the mechanisms of migration, polarization, differentiation, and immune-stimulatory functions of macrophages. Accordingly, in this article, we will explore the interaction between environmental chemicals and inflammatory macrophage processes at the molecular level and their association with tumor progression and carcinogenesis.

Electrospun and co-electrospun biopolymer nanofibers for skin wounds on diabetic patients: an overview

Wound healing treatment in diabetic patients worldwide represents around 2.1 trillion dollars to global health sectors. This is because of the complications presented in the wound healing process of skin ulcers, such as a lack of macrophage and fibroblast growth factors (TGF-β1 and PDGF, respectively) that are both needed for extracellular matrix (ECM) synthesis. Therefore, there is a need for research on new and cost-effective materials to enable ECM synthesis. Such materials include co-electrospun nanofibers used as wound dressings, since they have a similar morphology to the ECM, and therefore, possess the advantage of using different materials to accelerate the wound healing process. Co-electrospun nanofibers have a unique structural configuration, formed by a core and a shell. This configuration allows the protection and gradual liberation of healing agent compounds, which could be included in the core. Some of the materials used in nanofibers are polymers, including natural compounds, such as chitosan (which has been proven to possess antimicrobial and therapeutic activity) and gelatin (for its cell growth, adhesion, and organisational capacity in the wound healing process). Synthetics such as polyvinyl-alcohol (PVA) (mainly as a co-spinning agent to chitosan) can also be used. Another bioactive compound that can be used to enhance the wound healing process is eugenol, a terpenoid present in different medicinal plant tissues that have scarring properties. Therefore, the present review analyses the potential use of co-electrospun nanofibers, with chitosan-PVA-eugenol in the core and gelatin in the shell as a wound dressing for diabetic skin ulcers.

A sweet spot for macrophages: Focusing on polarization

Macrophages are a type of functionally plastic cells that can create a pro-/anti-inflammatory microenvironment for organs by producing different kinds of cytokines, chemokines, and growth factors to regulate immunity and inflammatory responses. In addition, they can also be induced to adopt different phenotypes in response to extracellular and intracellular signals, a process defined as M1/M2 polarization. Growing evidence indicates that glycobiology is closely associated with this polarization process. In this research, we review studies of the roles of glycosylation, glucose metabolism, and key lectins in the regulation of macrophages function and polarization to provide a new perspective for immunotherapies for multiple diseases.

Macrophage 3D migration: A potential therapeutic target for inflammation and deleterious progression in diseases

Macrophages are heterogeneous cells that have different physiological functions, such as chemotaxis, phagocytosis, endocytosis, and secretion of various factors. All physiological functions of macrophages are integral to homeostasis, immune defense and tissue repair. However, in several diseases, macrophages are recruited from the blood towards inflammatory sites. This process is called macrophage migration, which promotes deleterious disease progression. Macrophage migration is a key player in many inflammatory diseases, autoimmune diseases and cancers because it contributes to the accumulation of proinflammatory factors, the destruction of tissues and the development of tumors. Therefore, macrophage migration is proposed to be a potential therapeutic target. Macrophages migrate between two-dimensional (2D) and three-dimensional (3D) environments, implying that distinct migratory features and mechanisms are involved. Compared with the 2D migration of macrophages, 3D migration involves more complex variations in cellular morphology and dynamics. The structure of the extracellular matrix, a key factor, is modified in diseases that influence macrophage 3D migration. Macrophage 3D migration relates to disease pathology. Research that focuses on macrophage 3D migration is an emerging field and was reviewed in this article to indicate the molecular and cellular mechanisms of macrophage migration in 3D environments and to provide potential targets for controlling disease progression associated with this migration.

Obesity and diabetes as high-risk factors for severe coronavirus disease 2019 (Covid-19)

The outbreak of the coronavirus disease 2019 (Covid-19) has become an evolving worldwide health crisis. With the rising prevalence of obesity and diabetes has come an increasing awareness of their impacts on infectious diseases, including increased risk for various infections, post-infection complications and mortality from critical infections. Although epidemiological and clinical characteristics of Covid-19 have been constantly reported, no article has systematically illustrated the role of obesity and diabetes in Covid-19, or how Covid-19 affects obesity and diabetes, or special treatment in these at-risk populations. Here, we present a synthesis of the recent advances in our understanding of the relationships between obesity, diabetes and Covid-19 along with the underlying mechanisms, and provide special treatment guidance for these at-risk populations.

Tissue-resident macrophage inflammaging aggravates homeostasis dysregulation in age-related diseases

Organs and tissues contain a large number of tissue-resident macrophages (MΦ-Ts), which are essential for regulating homeostasis and ensuring a rapid response to injury. However, the environmental signals shaping MΦ-Ts phenotypes and the contribution of MΦ-Ts to pathological processes are just starting to be identified. MΦ-Ts isolated from aged animals or patients show alterations in morphology and distribution, defects in phagocytosis and autophagy, and loss of tissue-repair capacity. These variations are closely associated with age-associated disorders, such as inflammaging, which is characterized by cell senescence and a senescence-associated secretory phenotype (SASP) and is frequently observed in patients afflicted with chronic diseases. It seems that the role of these resident populations cannot be avoided in the treatment of aging-related diseases. This review will describe the mechanism by which MΦ-Ts support immune homeostasis and will then discuss how MΦ-Ts facilitate inflammaging and age-related diseases, which will be helpful in the development of new interventions and treatments for chronic diseases of the elderly.

The crosstalk of hedgehog, PI3K and Wnt pathways in diabetes

Hyperglycaemia causes pancreatic β-cells to release insulin that then attaches to a specific expression of receptor isoform and reverses high glucose concentrations. It is well known that insulin is capable of initiating insulin-receptor substrate (IRS)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB) signaling pathways in target cells; such as liver, adipose tissues, and muscles. However, recent discoveries indicate that many other pathways, such as the Hedgehog (Hh) and growth factor-stimulating Wingless-related integration (Wnt) signaling pathways; are activated in hyperglycaemia as well. Although these two pathways are traditionally thought to have a decisive role in cellular growth and differentiation only, recent reports show that they are involved in regulating cellular homeostasis and energy balance. While insulin-activated IRS/PI3K/PKB pathway cascades are primarily known to reduce glucose production, it was recently discovered to increase the Hh signaling pathway's stability, thereby activating the PI3K/PKB/mammalian target of rapamycin complex 2 (mTORC2) signaling pathway. The Hh signaling pathway not only plays a role in lipid metabolism, insulin sensitivity, inflammatory response, diabetes-related complications, but crosstalks with the Wnt signaling pathway resulting in improved insulin sensitivity and decrease inflammatory response in diabetes.

Combination of metformin and chlorogenic acid attenuates hepatic steatosis and inflammation in high-fat diet fed mice

Non-alcoholic fatty liver disease (NAFLD) has become an important health problem in the world. Natural products, with anti-inflammatory properties, are potential candidates for alleviating NAFLD. Metformin (MET) and chlorogenic acid (CGA) have been reported to be effective in the improvement of NAFLD. Here, we aimed to evaluate the efficacy of MET and CGA combination in ameliorating NAFLD in high-fat diet (HFD) fed mice. Fifty C57BL/6 male mice were divided into two groups, one fed a standard chow diet (n = 10) and the other was fed an HFD (n = 40) for 10 weeks. Animals in the HFD group were then randomly divided into a four groups (HFD, HFD + MET (0.25%), HFD + CGA (0.02%) and HFD + MET + CGA (0.25 + 0.02%). MET and CGA combination decreases fasting blood glucose and improves glucose intolerance. Decreased hepatic triglyceride level was associated with lower expression levels of fatty acid synthase and sterol regulatory element-binding protein-1c in MET+CGA treated mice. MET and CGA combination treatment resulted in the polarization of macrophages to the M2 phenotype, reduction of the expression of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6), and decreasing protein level of NF-kB p65. It was found that the lowering effect of combined MET and CGA on the expression of gluconeogenic genes was accompanied by increasing phosphorylation of glycogen synthase kinase 3β. Treatment of HFD mice with the combination of MET and CGA was found to be more effective at alleviating inflammation and lipid accumulation by increasing phosphorylation of AMP-activated protein kinase. In conclusion, these findings suggest that the MET + CGA combination might exert therapeutic effects against NAFLD.

The mNCP-SPI Score Predicting Risk of Severe COVID-19 among Mild-Pneumonia Patients on Admission

Purpose

To predict the risk of developing severe pneumonia among mild novel coronavirus pneumonia (mNCP) patients on admission.

Methods

A retrospective cohort study was conducted at three hospitals in Shanghai and Wuhan from January 2020 to February 2020. Real-time polymerasechain–reaction assays were used to detect COVID-19. A total of 529 patients diagnosed with NCP were recruited from three hospitals and classified by four severity types during hospitalization following the standards of the Chinese Diagnosis and Treatment of Pneumonia Caused by New Coronavirus Infection (eighth version). Patients were excluded if admitted by ICU on admission (n=92, on a general ward while meeting the condition of severe or critical type on admission (n=25), or there was insufficient clinical information (n=64). In sum, 348 patients with mNCP were finally included, and 68 developed severe pneumonia.

Results

mNCP severity prognostic index values were calculated based on multivariate logistic regression: history of diabetes (OR 2.064, 95% CI 1.010–4.683; p=0.043), time from symptom onset to admission ≥7 days (OR 1.945, 95% CI 1.054–3.587; p=0.033), lymphocyte count ≤0.8 (OR 1.816, 95% CI 1.008–3.274; p=0.047), myoglobin ≥90 mg/L (OR 2.496, 95% CI 1.235–5.047; p=0.011), and D-dimer ≥0.5 mg/L (OR 2.740, 95% CI 1.395–5.380; p=0.003). This model showed a c-statistics of 0.747, with sensitivity and specificity 0.764 and 0.644, respectively, under cutoff of 165.

Conclusion

We designed a clinical predictive tool for risk of severe pneumonia among mNCP patients to provided guidance for medicines. Further studies are required for external validation.

Diabetes is a risk factor for the progression and prognosis of COVID-19

BACKGOUND

To figure out whether diabetes is a risk factor influencing the progression and prognosis of 2019 novel coronavirus disease (COVID-19).

METHODS

A total of 174 consecutive patients confirmed with COVID-19 were studied. Demographic data, medical history, symptoms and signs, laboratory findings, chest computed tomography (CT) as well the treatment measures were collected and analysed.

RESULTS

We found that COVID-19 patients without other comorbidities but with diabetes (n = 24) were at higher risk of severe pneumonia, release of tissue injury-related enzymes, excessive uncontrolled inflammation responses and hypercoagulable state associated with dysregulation of glucose metabolism. Furthermore, serum levels of inflammation-related biomarkers such as IL-6, C-reactive protein, serum ferritin and coagulation index, D-dimer, were significantly higher (P < .01) in diabetic patients compared with those without, suggesting that patients with diabetes are more susceptible to an inflammatory storm eventually leading to rapid deterioration of COVID-19.

CONCLUSIONS

Our data support the notion that diabetes should be considered as a risk factor for a rapid progression and bad prognosis of COVID-19. More intensive attention should be paid to patients with diabetes, in case of rapid deterioration.