Inhibition of macrophage migration inhibitory factor reduces diabetic nephropathy in type II diabetes mice

Targeting Macrophages: Therapeutic Approaches in Diabetic Kidney Disease

Diabetes is not solely a metabolic disorder but also involves inflammatory processes. The immune response it incites is a primary contributor to damage in target organs. Research indicates that during the initial phases of diabetic nephropathy, macrophages infiltrate the kidneys alongside lymphocytes, initiating a cascade of inflammatory reactions. The interplay between macrophages and other renal cells is pivotal in the advancement of kidney disease within a hyperglycemic milieu. While M1 macrophages react to the inflammatory stimuli induced by elevated glucose levels early in the disease progression, their subsequent transition to M2 macrophages, which possess anti-inflammatory and tissue repair properties, also contributes to fibrosis in the later stages of nephropathy by transforming into myofibroblasts. Comprehending the diverse functions of macrophages in diabetic kidney disease and regulating their activity could offer therapeutic benefits for managing this condition.

Macrophage Migration Inhibitory Factor (MIF) is a Key Player in Dry Eye Disease

PURPOSE

To explore the role of the proinflammatory cytokine, macrophage migration inhibitory factor (MIF), in a murine model of dry eye disease (DED).

METHODS

The role of MIF on DED was determined using genetically MIF deficient mice and pharmacological inhibition of MIF. DED was induced with 0.5 mg of scopolamine via subcutaneous injection in wild type (WT) and mice lacking MIF (Mif-/-), three times a day for 21 days. DED signs, tear volume, ferning pattern and cytology impression were evaluated. Also, eye tissues were collected to determine transcripts of key inflammatory mediators and histopathological damage. In a second set of experiments, we neutralized MIF with ISO-1, an isozaxiline-derivative MIF tautomerase activity-inhibiting small molecule in WT mice, following an acute DED model for 10 days. ISO-1 was given starting on day 3 after DED induction and signs were evaluated, including a recovery phase in both experimental approaches.

RESULTS

When compared to WT, Mif-/- mice showed attenuated signs of DED like preserved mucin pattern and increased tear volume. Also, Mif-/- mice maintained conjunctival epithelial cells and less corneal damage, associated with lower levels of TNFα and IL-1β. At recovery phase, Mif-/- mice presented improved signs. Interestingly, in cornea and conjunctiva the absence of MIF selectively downregulated the transcription of inflammatory enzymes like inos and nox4 whereas displayed enhanced transcripts of il-4, il-13, tgfβ and cox2. Finally, pharmacological inhibition of MIF using ISO-1, replicated the above findings in the mouse model.

CONCLUSION

MIF is a central positive mediator of the inflammatory process in experimental DED, thus, targeting MIF could be used as a novel therapy in ocular surface inflammatory pathologies.

Macrophage Migration Inhibitory Factor (MIF) as a Stress Molecule in Renal Inflammation

Renal inflammation is an initial pathological process during progressive renal injury regardless of the initial cause. Macrophage migration inhibitory factor (MIF) is a truly proinflammatory stress mediator that is highly expressed in a variety of both inflammatory cells and intrinsic kidney cells. MIF is released from the diseased kidney immediately upon stimulation to trigger renal inflammation by activating macrophages and T cells, and promoting the production of proinflammatory cytokines, chemokines, and stress molecules via signaling pathways involving the CD74/CD44 and chemokine receptors CXCR2, CXCR4, and CXCR7 signaling. In addition, MIF can function as a stress molecule to counter-regulate the immunosuppressive effect of glucocorticoid in renal inflammation. Given the critical position of MIF in the upstream inflammatory cascade, this review focuses on the regulatory role and molecular mechanisms of MIF in kidney diseases. The therapeutic potential of targeting MIF signaling to treat kidney diseases is also discussed.

Betaine modulates MIF-mediated oxidative stress, inflammation, and fibrogenesis in Thioacetamide-induced Nephrotoxicity

BACKGROUND

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine with chemokine properties released by various immune and nonimmune cells. It contributes to the pathogenesis of many inflammatory, autoimmune diseases and malignant tumors.

OBJECTIVE

Our study aimed to investigate the role of betaine in the modulation of MIF-mediated oxidative stress, inflammation, and fibrogenesis during toxic kidney damage induced by thioacetamide (TAA).

METHODS

The experiment is performed on wild-type and knockout MIF-/- C57BL/6 mice. They are randomly divided into groups: Control; Bet-group, received betaine (2% wt/v dissolved in drinking water); MIF-/- mice group; MIF-/-+Bet; TAA-group, treated with TAA (200 mg/kg b.w.), intraperitoneally, 3x/week/8 weeks); TAA+Bet; MIF-/-+TAA, and MIF-/-+TAA+Bet group. After eight weeks of treatment, animals are sacrificed and kidney samples are taken to determine oxidative stress parameters, proinflammatory cytokines, profibrogenic factors, and histopathology of renal tissue Results: In MIF-/-mice, TAA decreases malondialdehyde (MDA) concentration, IL-6, tumor necrosis factor-alpha (TNF-, transforming growth factor-beta 1 (TGF-1) and plateled-derived growth factor-BB (PDGF-BB) and increases superoxide dismutases (SOD) and catalase (CAT) activities, as well as glutathione (GSH) content in kidneys, compared to TAA group. Betaine alleviates the mechanism of MIF-mediated effects in TAA-induced nephrotoxicity, reducing MDA, IL-6, TNF-, TGF-1, and PDGF-BB, and increasing SOD and CAT activity, as well as GSH levels.

CONCLUSION

MIF mediates TAA-induced nephrotoxicity by increasing oxidative stress, inflammation, and profibrogenic mediators. MIF-targeted therapy could potentially alleviate oxidative stress and inflammation in the kidney, as well as pathohistological changes in renal tissue, but the exact mechanism of its action is not completely clear. Betaine alleviates MIF nephrotoxic effects by increasing the antioxidative capacity of kidney cells, and decreasing lipid peroxidation and cytokine production in the renal tissue. It suggests that betaine can be used for the prevention of kidney damage.

Macrophage migration inhibitory factor (MIF): A multifaceted cytokine regulated by genetic and physiological strategies

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine encoded within a functionally polymorphic genetic locus. MIF was initially recognized as a cytokine generated by activated T cells, but in recent days it has been identified as a multipotent key cytokine secreted by many other cell types involved in immune response and physiological processes. MIF is a highly conserved 12.5 kDa secretory protein that is involved in numerous biological processes. The expression and secretion profile of MIF suggests that MIF to be ubiquitously and constitutively expressed in almost all mammalian cells and is vital for numerous physiological processes. MIF is a critical upstream mediator of host innate and adaptive immunity and survival pathways resulting in the clearance of pathogens thus playing a protective role during infectious diseases. On the other hand, MIF being an immune modulator accelerates detrimental inflammation, promotes cancer metastasis and progression, thus worsening disease conditions. Several reports demonstrated that genetic and physiological factors, including MIF gene polymorphisms, posttranslational regulations, and receptor binding control the functional activities of MIF. Taking into consideration the multi-faceted role of MIF both in physiology and pathology, we thought it is timely to review and summarize the expressional and functional regulation of MIF, its functional mechanisms associated with its beneficial and pathological roles, and MIF-targeting therapies. Thus, our review will provide an overview on how MIF is regulated, its response, and the potency of the therapies that target MIF.

Nrf-2 mediated heme oxygenase-1 activation contributes to the anti-inflammatory and renal protective effects of Ginkgo biloba extract in diabetic nephropathy

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba extract (GbE) is derived from a medicinal plant and suggested as a treatment for diabetic nephropathy (DN), but the mechanism was not clarified.

AIM OF STUDY

The present study investigated whether GbE prevented DN via activation of heme oxygenase (HO)-1.

MATERIALS AND METHODS

Streptozotocin-induced diabetic mice were fed a high-fat diet to generate DN. Human and murine podocytes were used for the in vitro study.

RESULTS

GbE improved renal function via decreasing glomerular hypertrophy, the kidney/body weight ratio, and albuminuria in DN mice. GbE reversed the reduction of synaptopodin and nephrin and enhanced HO-1 expression in the kidneys of DN mice. GbE decreased the enhancement of TNF-α, IL-6, fibronectin, and lipid accumulation in the glomeruli of DN mice. GbE attenuated the uptake of oxidized low-density lipoprotein and reduced the production of ROS in high glucose-stimulated podocytes, and HO-1 inhibitor treatment abrogated the protective effects of GbE. Nuclear factor erythroid 2-related factor 2 (Nrf-2) siRNA significantly abolished the beneficial effects of GbE via decreased HO-1 expression and enhanced TNF-α and IL-6 levels.

CONCLUSIONS

GbE protected podocytes against hyperglycemia and prevented the development of DN via Nrf-2/HO-1 activation. Our findings provide further mechanistic insight into the potential use of GbE in clinical DN.

Polysaccharides from the Fleshy Fruits of Camellia oleifera Attenuate the Kidney Injury in High-Fat Diet/Streptozotocin-Induced Diabetic Mice

The fleshy fruits of Camellia oleifera Abel are the immature fruits of C. oleifera, which are infected by Exobasidium vexans Massee and then turn to be intumescent and hollowed. They contain rich trace elements and vitamin C and are eaten directly as wild fruits in the Chinese countryside. Recent studies report that C. oleifera has anti-inflammatory and antioxidative effects. The current study, for the first time, evaluates the renal protective capacity of polysaccharides from the fleshy fruits of C. oleifera (CFFP) in streptozotocin-induced diabetic mice fed high-fat diets. The diabetic mice were orally administered CFFP for 3 months to evaluate the renoprotective function of CFFP. Our results indicated that 250 mg/kg CFFP significantly alleviated diabetes-induced renal injury by decreasing serum creatine, blood urea nitrogen levels, the kidney/body weight ratio, expression of fibronectin and collagen, as well as the secretion of tumor necrosis factor-α and interleukin-6. Additionally, 250 mg/kg CFFP could significantly ameliorate renal oxidative stress through increasing glutathione levels and lowering malondialdehyde contents. We confirmed that CFFP could exert antioxidative, anti-inflammatory, and antifibrosis activities. CFFP might be a potential therapeutic agent, and the fleshy fruits of C. oleifera might be a diet therapy for diabetic patients in the future.

Accelerated Kidney Aging in Diabetes Mellitus

With aging, the kidney undergoes inexorable and progressive changes in structural and functional performance. These aging-related alterations are more obvious and serious in diabetes mellitus (DM). Renal accelerated aging under DM conditions is associated with multiple stresses such as accumulation of advanced glycation end products (AGEs), hypertension, oxidative stress, and inflammation. The main hallmarks of cellular senescence in diabetic kidneys include cyclin-dependent kinase inhibitors, telomere shortening, and diabetic nephropathy-associated secretory phenotype. Lysosome-dependent autophagy and antiaging proteins Klotho and Sirt1 play a fundamental role in the accelerated aging of kidneys in DM, among which the autophagy-lysosome system is the convergent mechanism of the multiple antiaging pathways involved in renal aging under DM conditions. Metformin and the inhibitor of sodium-glucose cotransporter 2 are recommended due to their antiaging effects independent of antihyperglycemia, besides angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Additionally, diet intervention including low protein and low AGEs with antioxidants are suggested for patients with diabetic nephropathy (DN). However, their long-term benefits still need further study. Exploring the interactive relationships among antiaging protein Klotho, Sirt1, and autophagy-lysosome system may provide insight into better satisfying the urgent medical needs of elderly patients with aging-related DN.

Excessive walking exercise precipitates diabetic neuropathic foot pain: hind paw suspension treadmill exercise experiment in a rat model

The harmful effects of excessive mechanical loading on diabetic neuropathy and the reason diabetic neuropathic symptoms are common in feet are unclear. In this study, the hind paw suspension treadmill exercise model was used in rats to investigate whether mechanical loading applied to the front paws precipitates neuropathic pain, especially in diabetic conditions. Thirty-two rats were divided into six groups according to the presence of diabetes (DM) and the intensity of mechanical loading applied to the front paws: DM-Hi (high-intensity); DM-Lo (low-intensity); DM-No (non-mechanical loading); Sham-Hi; Sham-Lo; and Sham-No. DM was induced by streptozotocin injection. For high-intensity or low-intensity mechanical loading, treadmill walking exercise was conducted with or without hind paw suspension, respectively. The mechanical withdrawal threshold of the front paw decreased significantly after 8 weeks only in the DM mechanical loading groups (DM-Hi and DM-Lo), and high-intensity loading more significantly decreased the front-paw withdrawal threshold than low-intensity loading. In the DM-Hi group only, macrophage migration inhibitory factor (MIF) increased significantly, and intra-epidermal nerve fibers (IENF) in the front paws decreased significantly. In diabetic conditions, mechanical overloading such as excessive walking is likely to precipitate mechanical allodynia and damage IENF¸ which could explain why diabetic neuropathic symptoms are common in feet. This finding might be related to up-regulation of intracellular signaling cascades such as MIF, rather than inflammatory processes.

Pathogenic Pathways and Therapeutic Approaches Targeting Inflammation in Diabetic Nephropathy

Diabetic nephropathy (DN) is associated with an increased morbidity and mortality, resulting in elevated cost for public health systems. DN is the main cause of chronic kidney disease (CKD) and its incidence increases the number of patients that develop the end-stage renal disease (ESRD). There are growing epidemiological and preclinical evidence about the close relationship between inflammatory response and the occurrence and progression of DN. Several anti-inflammatory strategies targeting specific inflammatory mediators (cell adhesion molecules, chemokines and cytokines) and intracellular signaling pathways have shown beneficial effects in experimental models of DN, decreasing proteinuria and renal lesions. A number of inflammatory molecules have been shown useful to identify diabetic patients at high risk of developing renal complications. In this review, we focus on the key role of inflammation in the genesis and progression of DN, with a special interest in effector molecules and activated intracellular pathways leading to renal damage, as well as a comprehensive update of new therapeutic strategies targeting inflammation to prevent and/or retard renal injury.

Remodeling adipose tissue inflammasome for type 2 diabetes mellitus treatment: Current perspective and translational strategies

Obesity-associated type 2 diabetes mellitus (T2DM) is characterized by low-grade chronic systemic inflammation that arises primarily from the white adipose tissue. The interplay between various adipose tissue-derived chemokines drives insulin resistance in T2DM and has therefore become a subject of rigorous investigation. The adipocytokines strongly associated with glucose homeostasis include tumor necrosis factor-α, various interleukins, monocyte chemoattractant protein-1, adiponectin, and leptin, among others. Remodeling the adipose tissue inflammasome in obesity-associated T2DM is likely to treat the underlying cause of the disease and bring significant therapeutic benefit. Various strategies have been adopted or are being investigated to modulate the serum/tissue levels of pro- and anti-inflammatory adipocytokines to improve glucose homeostasis in T2DM. These include use of small molecule agonists/inhibitors, mimetics, antibodies, gene therapy, and other novel formulations. Here, we discuss adipocytokines that are strongly associated with insulin activity and therapies that are under investigation for modulation of their levels in the treatment of T2DM.

MIF and insulin: Lifetime companions from common genesis to common pathogenesis

Pro-inflammatory nature of macrophage migration inhibitory factor (MIF) has been generally related to the propagation of inflammatory and autoimmune diseases. But this molecule possesses many other peculiar functions, unrelated to the immune system, among which is its supportive role in the post-translational modifications of insulin. In this way MIF enables proper insulin conformation within the pancreatic beta cell and its full activity. The inherent or acquired changes in MIF expression might therefore lead to different insulin processing and initiation of autoimmunity. The relation between MIF and insulin does not stop at this point; these two molecules continue to interact during pathological states characterized by inflammation and insulin resistance. In this context, MIF indirectly and negatively influences insulin action by boosting inflammatory environment and disabling target cells to respond to insulin. On the other side, insulin might interfere with MIF action as well, acting as an anti-inflammatory mediator. Therefore, the proper interaction between MIF and insulin is crucial for maintaining homeostasis, while anti-inflammatory therapies based on the systemic MIF blockage may disturb this balance. This review covers MIF-insulin relationship in the physiological and pathological conditions and discusses the approaches for MIF inhibition and their net effect specifically considering possible impact on insulin misfolding and the possible misinterpretation of previous results due to the discovery of MIF functional homolog D-dopachrome tautomerase.

Association between Beta2-Adrenergic Receptor Agonists and the Risk of Vascular Complications in Diabetic Patients: A Population-Based Cohort Study

Beta2-adrenergic receptor (β2AR) agonists can have protective effects targeting macrophage activation, but research on human subjects has not been done. This study was designed to assess the relationship between the use of β2AR agonists and diabetic vascular complications. Using data from the Korean National Health Insurance Service, adults first diagnosed with diabetes in 2004 (n = 249,222) were followed up until 31 December 2015. Propensity score matching was performed between case and control groups (n = 5179 in each), and multivariate analysis was conducted. The β2AR agonist group was divided into quartiles according to the duration of β2AR agonist use. During the follow-up, the incidence of vascular complications gradually decreased as the duration of β2AR agonist administration increased. Multivariate analysis revealed that the hazard ratio for all composite vascular complications was 0.80 (95% CI, 0.75–0.86, p < 0.001) in the longest quartile of β2AR agonist use as compared with the control group after adjusting for confounding variables. The association between the duration of β2AR agonist use and the risk of each vascular complication including cerebrovascular, peripheral vascular, peripheral neural, renal, and ophthalmic complications was consistent, and the risks were significantly lower in the longest users than the control group. Long-term use of β2AR agonists may exert a protective effect against diabetic vascular complications.

Macrophage migration inhibitory factor promotes renal injury induced by ischemic reperfusion

Macrophage migration inhibitory factor (MIF) is pleiotropic cytokine that has multiple effects in many inflammatory and immune diseases. This study reveals a potential role of MIF in acute kidney injury (AKI) in patients and in kidney ischemic reperfusion injury (IRI) mouse model in MIF wild‐type (WT) and MIF knockout (KO) mice. Clinically, plasma and urinary MIF levels were largely elevated at the onset of AKI, declined to normal levels when AKI was resolved and correlated tightly with serum creatinine independent of disease causes. Experimentally, MIF levels in plasma and urine were rapidly elevated after IRI‐AKI and associated with the elevation of serum creatinine and the severity of tubular necrosis, which were suppressed in MIF KO mice. It was possible that MIF may mediate AKI via CD74/TLR4‐NF‐κB signalling as mice lacking MIF were protected from AKI by largely suppressing CD74/TLR‐4‐NF‐κB associated renal inflammation, including the expression of MCP‐1, TNF‐α, IL‐1β, IL‐6, iNOS, CXCL15(IL‐8 in human) and infiltration of macrophages, neutrophil, and T cells. In conclusion, our study suggests that MIF may be pathogenic in AKI and levels of plasma and urinary MIF may correlate with the progression and regression of AKI.

Macrophage migration inhibitory factor antagonist (p425) ameliorates kidney histopathological and functional changes in diabetic rats

Introduction:

It is hypothesized that increased macrophage migration inhibitory factor (MIF) expression may contribute to diabetic nephropathy (DN) pathogenesis. The aim of the present study was to investigate the renal effects of MIF inhibition in a diabetic experimental model.

Methods:

Eighteen male Wistar rats (230 ± 20 g) were divided into three groups: 1) control, 2) diabetic (STZ, 50 mg/kg, dissolved in saline, ip), 3) diabetic + MIF antagonist (p425, 1 mg/kg per day, ip, on the 21th day, for 21 consecutive days). The treatment started since we founwd a significant increase in urine albumin excretion (UAE) rate in the diabetic rats in comparison with the control rats. The rats were kept individually in metabolic cages (8 AM-2 PM) and urine samples were collected in the 21 and 42th day. At the end, blood and tissue samples were collected for biochemical (BS, UPE, urine GAG, BUN, Cr, Na, and K) and histological analyses.

Results:

The results of this study showed that MIF antagonist (p425) significantly decreased urine protein and GAG excretion, urine protein/creatinine ratio, and serum BUN and Cr in the streptozotocin-induced DN in the rats. Pathological changes were significantly alleviated in the MIF antagonist (p425)-administered DN rats.

Conclusion:

Collectively, these data suggested that MIF antagonist (p425) was able to protect against functional and histopathological injury in the DN.

A Glimpse of the Mechanisms Related to Renal Fibrosis in Diabetic Nephropathy

Diabetic nephropathy (DN) is a common kidney disease in people with diabetes, which is also a serious microvascular complication of diabetes and the main cause of end-stage renal disease (ESRD) in developed and developing countries. Renal fibrosis is a finally pathological change in DN. Nevertheless, the relevant mechanism of cause to renal fibrosis in DN is still complex. In this review, we summarized that the role of cell growth factors, epithelial-mesenchymal transition (EMT) in the renal fibrosis of DN, we also highlighted the miRNA and inflammatory cells, such as macrophage, T lymphocyte, and mastocyte modulate the progression of DN. In addition, there are certain other mechanisms that may yet be conclusively defined. Recent studies demonstrated that some of the new signaling pathways or molecules, such as Notch, Wnt, mTOR, Epac-Rap-1 pathway, may play a pivotal role in the modulation of ECM accumulation and renal fibrosis in DN. This review aims to elucidate the mechanism of renal fibrosis in DN and has provided new insights into possible therapeutic interventions to inhibit renal fibrosis and delay the development of DN.

Role of the Immune System in Diabetic Kidney Disease

PURPOSE OF REVIEW

The purpose of this review is to examine the proposed role of immune modulation in the development and progression of diabetic kidney disease (DKD).

RECENT FINDINGS

Diabetic kidney disease has not historically been considered an immune-mediated disease; however, increasing evidence is emerging in support of an immune role in its pathophysiology. Both systemic and local renal inflammation have been associated with DKD. Infiltration of immune cells, predominantly macrophages, into the kidney has been reported in a number of both experimental and clinical studies. In addition, increased levels of circulating pro-inflammatory cytokines have been linked to disease progression. Consequently, a variety of therapeutic strategies involving modulation of the immune response are currently being investigated in diabetic kidney disease. Although no current therapies for DKD are directly based on immune modulation many of the therapies in clinical use have anti-inflammatory effects along with their primary actions. Macrophages emerge as the most likely beneficial immune cell target and compounds which reduce macrophage infiltration to the kidney have shown potential in both animal models and clinical trials.

Are the Therapeutic Effects of Huangqi (Astragalus membranaceus) on Diabetic Nephropathy Correlated with Its Regulation of Macrophage iNOS Activity?

Objective

To investigate the correlation between the clinical effects of Huangqi (Astragalus membranaceus) on different stages of diabetic nephropathy (DN) and the pharmacological effect of Huangqi on the activity of inducible nitric oxide synthase (iNOS) in macrophages in different states.

Methods

The PubMed, China National Knowledge Infrastructure, and Wanfang databases were searched. Clinical data was sourced from papers on treatment of different stages of DN with Huangqi, and pharmacological data was from papers on the effects of Huangqi on the iNOS activity of macrophages in a resting or an activated state.

Results

Meta-analysis of Huangqi injections on stages III and III-IV DN and randomized controlled trials on other stages showed that Huangqi had therapeutic effects on different stages of DN and on macrophages in different states: inducing normal macrophages in a resting state to generate nitric oxide (NO), tumor necrosis factor-α, and so forth upon iNOS activation; inhibiting NO generation by normal lipopolysaccharide- (LPS-) activated macrophages; and enhancing NO generation by LPS-induced macrophages from patients with renal failure.

Conclusions

Huangqi can regulate iNOS activity of macrophages in different states in vitro. These biphasic or antagonistic effects may explain why Huangqi can be used to treat different stages of DN.

Proinflammatory cytokine MIF plays a role in the pathogenesis of type-2 diabetes mellitus, but does not affect hepatic mitochondrial function

BACKGROUND

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays an important role in the pathogenesis of type 2 diabetes mellitus (T2DM). Although the effect of high glucose on liver function has been described, the role of MIF in hepatic mitochondrial function during T2DM has not been studied.

OBJECTIVE

We examine the influence of MIF to hepatic mitochondrial function in T2DM mouse model.

METHODS

WT and Mif^-/- BALB/c mice were treated with a single dose of streptozotocin (STZ). After an 8-week follow-up, serum glucose, proinflammatory cytokines, C-reactive protein (CRP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzyme quantification, and liver histological analyses were performed. Liver mitochondria were extracted, and mitochondrial function was evaluated by oximetry, swelling and peroxide production.

RESULTS

Following treatment with STZ, WT mice (WT/STZ) developed significant hyperglycemia and high serum levels of MIF, tumor necrosis factor (TNF)-α, interleukin-β (IL-β), and CRP. Liver damage enzymes ALT and AST were found at high levels. In contrast, Mif^-/-STZ lacked serum MIF levels and showed smaller increases in blood glucose, less TNF-α, IL-1β, CPR, ALT and AST, and failure to develop clinical signs of disease compared to the WT/STZ group. Mitochondria extracted from the Mif^-/-STZ liver showed similar respiratory control (RC) to WT/STZ or healthy mice with glutamate/malate or succinate as substrates. The four respiratory chain complexes also had comparable activities. WT/STZ-isolated mitochondria showed low swelling with calcium compared to mitochondria from Mif^-/-STZ or healthy mice. Peroxide production was comparable in all groups.

CONCLUSION

These results show although high systemic levels of MIF contribute to the development of T2DM pathology, the liver mitochondria remain unaltered. Importantly, the absence of MIF reduced the pathology of T2DM, also without altering liver mitochondrial function. These support MIF as a therapeutic target for the treatment of this disease in humans.

A genetic role for macrophage migration inhibitory factor (MIF) in Epinephelus awoara infected with Vibrio parahaemolyticus

Macrophage migration inhibitory factor (MIF) is a key pro-inflammatory cytokine in immuno-inflammatory diseases. For the first time, we examined the expression of MIF in Epinephelus awoara ( E. awoara). MIF expressions have been detected in the head kidney, spleen, liver, brain, intestine, gill, heart, stomach, and muscle of E. awoara infected with Vibrio parahaemolyticus. The mRNA levels observed in infected groupers were higher than those in healthy groupers. MIF, tumor necrosis factor-α (TNF-α), and interleukin-1 (IL-1) tissue levels have been measured by ELISA. A significant increase in MIF, TNF-α, and IL-1 tissue levels have been found in the treatment groups compared with those in controls. MIF, TNF-α and IL-1 tissue levels in the spleen, head kidney, intestine, and liver of E. awoara during the challenge trial with V. parahaemolyticus were significantly higher than those in controls. There was evidence of functions of MIF in a positive feedback loop with TNF-α and IL-1 that could perpetuate the inflammatory process in grouper infected with V. parahaemolyticus. In conclusion, these results indicated that MIF was related to pathogen-induced immune response.

Macrophage Migration Inhibitory Factor in Clinical Kidney Disease

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine implicated in acute and chronic inflammatory conditions, including sepsis, autoimmune disease, atherogenesis, plaque instability, and pulmonary arterial hypertension. MIF in plasma and urine is significantly elevated in patients with acute kidney injury (AKI) and elevated MIF in serum is associated with markers of oxidative stress, endothelial dysfunction, arterial stiffness, and markers of myocardial damage in chronic kidney disease (CKD). Furthermore, MIF seems to be involved in vascular processes and cardiovascular disease associated with CKD, glomerulonephritis, autosomal dominant polycystic kidney disease, and possibly also in progression to renal failure. Moreover, in active anti-neutrophil cytoplasmatic antibody-associated vasculitis, plasma MIF levels have been shown to be significantly elevated as compared with samples from patients in remission. A significant difference in the genotype frequency of high production MIF -173 G/C genotype has been found in end-stage renal disease, compared to controls. Inhibition of MIF in a diabetic nephropathy model ameliorated blood glucose and albuminuria and in a model of adult polycystic kidney disease cyst growth was delayed. Preclinical studies support a potential therapeutic role for MIF in AKI and in a number of CKDs, whereas these data in human disease are still observational. Future interventional studies are needed to delineate the role of MIF as a treatment target in clinical kidney disease.

The protective effect of Trillin LPS-induced acute lung injury by the regulations of inflammation and oxidative state

Inflammation response and oxidative stress have been reported to be involved in the pathogenesis of acute lung injury (ALI). Accordingly, anti-inflammatory treatment is proposed to be a possible efficient therapeutic strategy for ALI. The purpose of our present study was to evaluate the anti-inflammatory efficacy of trillin (Tr) on ALI induced by lipopolysaccharide (LPS) in mice and explore the underlying mechanism. BALB/c mice received Tr (50, 100 mg/kg) intraperitoneally 1 h prior to the intratracheal instillation of lipopolysaccharide (LPS) challenge. Pretreatment with Tr at the dose of 50, 100 mg/kg markedly ameliorated lung wet-to-dry weight (W/D) ratio, myeloperoxidase (MPO) activity and pulmonary histopathological conditions. In addition, the protective efficacy of Tr might be attributed to the down-regulations of neutrophil infiltration, malondialdehyde (MDA), inflammatory cytokines and the up-regulations of super-oxide dismutase (SOD), catalase(CAT), glutathione(GSH), Glutathione Peroxidase(GSH-Px) in bronchoalveolar lavage fluid (BALF). Meanwhile, our study revealed some correlations between (NF-E2-related factor 2) Nrf2/heme oxygenase (HO)-1/nuclear factor-kappa B (NF-κB) pathways and the beneficial effect of Tr, as evidenced by the significant up-regulations of HO-1 and Nrf2 protein expressions as well as the down-regulations of p-NF-κB and p-inhibitor of NF-κB (IκB) in lung tissues. Taken together, our results indicated that Tr exhibited protective effect on LPS-induced ALI by the regulations of related inflammatory events via the activations of Nrf2, HO-1 and NF-κB pathway. The current study indicated that Tr could be a potentially effective candidate medicine for the treatment of ALI.

Adenosine A2 a receptor stimulation prevents proteinuria in diabetic rats by promoting an anti-inflammatory phenotype without affecting oxidative stress

AIM

Diabetic patients are at increased risk for kidney disease. There is presently no clinical treatment available that effectively protects kidney function in diabetics. This study investigates whether chronic stimulation of the adenosine A2a receptor (A2a AR) protects kidney function in insulinopenic diabetic rats.

METHODS

Streptozotocin-induced diabetic rats and corresponding controls were chronically treated with the adenosine A2a AR agonist CGS21680 throughout the four-week diabetes duration. Kidney function was thereafter investigated, and urine and plasma samples were collected for analysis of protein, oxidative stress and inflammatory markers.

RESULTS

Glomerular filtration rate, renal blood flow, filtration fraction and diabetes-induced kidney hypoxia were all unaffected by chronic A2a AR stimulation. Furthermore, diabetic rats had increased oxidative stress, which was further increased by chronic A2a AR stimulation. However, the 10-fold increased urinary protein excretion observed in the diabetic rats was completely prevented by chronic A2a AR stimulation. These beneficial effects were accompanied by reduced levels of the pro-inflammatory TNF-α and increased levels of the anti-inflammatory IL-10 as well as decreased infiltration of macrophages, glomerular damage and basement membrane thickness.

CONCLUSION

Chronic A2a AR stimulation prevents proteinuria and glomerular damage in experimental diabetes via an anti-inflammatory mechanism independent of oxidative stress and kidney hypoxia.

Role of Macrophage Migration Inhibitory Factor in Obesity, Insulin Resistance, Type 2 Diabetes, and Associated Hepatic Co-Morbidities: A Comprehensive Review of Human and Rodent Studies

Obesity is associated with a chronic low-grade inflammatory state that drives the ­development of obesity-related co-morbidities such as insulin resistance/type 2 diabetes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular disease. This metabolic inflammation is thought to originate in the adipose tissue, which becomes inflamed and insulin resistant when it is no longer able to expand in response to excess caloric and nutrient intake. The production of inflammatory mediators by dysfunctional adipose tissue is thought to drive the development of more complex forms of disease such as type 2 diabetes and NAFLD. An important factor that may contribute to metabolic inflammation is the cytokine macrophage migration inhibitory factor (MIF). Increasing evidence suggests that MIF is released by adipose tissue in obesity and that it is also involved in metabolic and inflammatory processes that underlie the development of obesity-related pathologies. This review provides a comprehensive summary of our current knowledge on the role of MIF in obesity, its production by adipose tissue, and its involvement in the development of insulin resistance, type 2 diabetes, and NAFLD. We discuss the main findings from recent clinical studies in obese subjects and weight-loss intervention studies as well as results from clinical studies in patients with insulin resistance and type 2 diabetes. Furthermore, we summarize findings from experimental disease models studying the contribution of MIF in obesity and insulin resistance, type 2 diabetes, and hepatic lipid accumulation and fibrosis. Although many of the findings support a pro-inflammatory role of MIF in disease development, recent reports also provide indications that MIF may exert protective effects under certain conditions.

Macrophage migration inhibitory factor as a potential predictor for requirement of renal replacement therapy after orthotopic liver transplantation

Acute kidney injury (AKI) after orthotopic liver transplantation (OLT) is associated with a poor clinical outcome. Because there is no specific treatment for postoperative AKI, early recognition and prevention are fundamental therapeutic approaches. Concentrations of the proinflammatory cytokine macrophage migration inhibitory factor (MIF) are elevated in patients with kidney disease. We hypothesized that plasma MIF concentrations would be greater in patients developing AKI after OLT compared with patients with normal kidney function. Twenty-eight patients undergoing OLT were included in the study. Kidney injury was classified according to AKI network criteria. Fifteen patients (54%) developed severe AKI after OLT, 11 (39%) requiring renal replacement therapy (RRT). On the first postoperative day, patients with severe AKI had greater plasma MIF concentrations (237 ± 123 ng/mL) than patients without AKI (95 ± 63 ng/mL; P < 0.001). The area under the receiver operating characteristic (ROC) curve for predicting severe AKI was 0.87 [95% confidence interval (CI), 0.69-0.97] for plasma MIF, 0.61 (95% CI, 0.40-0.79) for serum creatinine (sCr), and 0.90 (95% CI, 0.72-0.98) for delta serum creatinine (ΔsCr). Plasma MIF (P = 0.02) and ΔsCr (P = 0.01) yielded a better predictive value than sCr for the development of severe AKI. Furthermore, the area under the ROC curve to predict the requirement of RRT was 0.87 (95% CI, 0.68-0.96) for plasma MIF, 0.65 (95% CI, 0.44-0.82) for sCr, and 0.72 (95% CI, 0.52-0.88) for ΔsCr. Plasma MIF had a better predictive value than sCr for the requirement of RRT (P = 0.02). In conclusion, postoperative plasma MIF concentrations were elevated in patients who developed severe AKI after OLT. Furthermore, plasma MIF concentrations showed a good prognostic value for identifying patients developing severe AKI or requiring postoperative RRT after OLT.

TNF-α and microalbuminuria in patients with type 2 diabetes mellitus

AIM

Recent evidence suggests that chronic subclinical inflammation plays a key role in the pathogenesis and progression of diabetic nephropathy. Aim of the present study was to investigate possible correlation between the presence and degree of microalbuminuria and markers of inflammation in patients with type 2 diabetes mellitus (DM).

PATIENTS-METHODS

Eighty patients were enrolled and clinical and laboratory data were recorded. Albumin-creatinine ratio (ACR) was calculated in first-morning urine samples. Serum and urinary tumor necrosis factor-α (TNF-α) levels were determined by ELISA.

RESULTS

Forty-five patients had normoalbuminuria, 33 microalbuminuria, and 2 macroalbuminuria. Patients with microalbuminuria were older, with higher glycosylated hemoglobin levels (HbA1c) and they more frequently had diabetic retinopathy, neuropathy, and cardiovascular disease and were on treatment with angiotensin converting enzyme inhibitors (ACEi) and/or angiotensin receptor blockers (ARBs). ACR was significantly correlated with the presence of cardiovascular disease, hypertension, and HbA1c levels and the administration of clopidogrel and ACEi or ARBs. ACR was not correlated with C-reactive protein, fibrinogen, or serum TNF-α levels but had a strong correlation with urinary TNF-α levels.

CONCLUSIONS

In patients with type 2 DM, urinary, but not serum, TNF-α levels are associated with the presence and severity of microalbuminuria.