Diabetes exacerbates inflammatory responses to ischemia-reperfusion

Early Post-Renal Transplant Hyperglycemia

CONTEXT

Though posttransplant diabetes mellitus (PTDM, occurring > 45 days after transplantation) and its complications are well described, early post-renal transplant hyperglycemia (EPTH) (< 45 days) similarly puts kidney transplant recipients at risk of infections, rehospitalizations, and graft failure and is not emphasized much in the literature. Proactive screening and management of EPTH is required given these consequences.

OBJECTIVE

The aim of this article is to promote recognition of early post-renal transplant hyperglycemia, and to summarize available information on its pathophysiology, adverse effects, and management.

METHODS

A PubMed search was conducted for "early post-renal transplant hyperglycemia," "immediate posttransplant hyperglycemia," "post-renal transplant diabetes," "renal transplant," "diabetes," and combinations of these terms. EPTH is associated with significant complications including acute graft failure, rehospitalizations, cardiovascular events, PTDM, and infections.

CONCLUSION

Patients with diabetes experience better glycemic control in end-stage renal disease (ESRD), with resurgence of hyperglycemia after kidney transplant. Patients with and without known diabetes are at risk of EPTH. Risk factors include elevated pretransplant fasting glucose, diabetes, glucocorticoids, chronic infections, and posttransplant infections. We find that EPTH increases risk of re-hospitalizations from infections (cytomegalovirus, possibly COVID-19), acute graft rejections, cardiovascular events, and PTDM. It is essential, therefore, to provide diabetes education to patients before discharge. Insulin remains the standard of care while inpatient. Close follow-up after discharge is recommended for insulin adjustment. Some agents like dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists have shown promise. The tenuous kidney function in the early posttransplant period and lack of data limit the use of sodium-glucose cotransporter 2 inhibitors. There is a need for studies assessing noninsulin agents for EPTH to decrease risk of hypoglycemia associated with insulin and long-term complications of EPTH.

Modulation of Nitric Oxide Bioavailability Attenuates Ischemia-Reperfusion Injury in Type II Diabetes

BACKGROUND

Diabetes mellitus increases the susceptibility of free tissue transplantations to ischemia-reperfusion injury. The aim of this study was to enhance nitric oxide (NO) bioavailability through exogenous NO synthase and the substrate L-arginine to attenuate ischemia reperfusion-induced alterations in a type 2 diabetes rodent model.

MATERIAL AND METHODS

Sixty-four Wistar rats were divided into 8 experimental groups. Type 2 diabetes was established over 3 months with a combination of a high-fat diet and streptozotocin. A vascular pedicle isolated rat skin flap model that underwent 3 h of ischemia was used. At 30 min before ischemia, normal saline, endothelial NOSs (eNOSs), inducible NOSs, neuronal NOSs (1 and 2 IU), and L-arginine (50 mg/kg body weight) were administered by intravenous infusion alone or in combination. Ischemia-reperfusion-induced alterations were measured 5 days after the operation.

RESULTS

The three isoforms of NOS significantly increased the flap vitality rate (VR) between 20% and 28% as compared to the control group (3%). Sole L-arginine administration increased the VR to 33%. The combination of L-arginine with NOS resulted in a further increase in flap VRs (39%-50%). Best results were achieved with the combination of eNOS and L-arginine (50%). An increase in enzyme dosage led to decreased VRs in all NOS isoforms alone and even in combination with L-arginine.

CONCLUSION

Modulation of NO bioavailability through the exogenous application of NOSs and L-arginine significantly attenuated ischemia-reperfusion-induced alterations in a type 2 diabetic skin flap rat model. The combination of enzyme and substrate result in the highest VRs. Higher enzyme dosage seems to be less effective. This pharmacological preconditioning could be an easy and effective interventional strategy to support the conversion of L-arginine to NO in ischemic and in type 2 diabetic conditions.

Endogenous Regulatory T Cells Promote M2 Macrophage Phenotype in Diabetic Stroke as Visualized by Optical Imaging

Regulatory T cells (Tregs) play an immunosuppressive role in various diseases, yet their function remains controversial in stroke and obscure in diabetic stroke. In the present study, Tregs were found downregulated in the peripheral blood of type 2 diabetes mellitus (T2DM) stroke models and patients compared with controls. In ischemic stroke mice (both T2DM and wild type), endogenous Tregs boosted by CD28SA increased CD206+ M2 macrophage/microglia cells, decreased infarct volumes, and improved neurological recovery. Our results demonstrated the potential of boosting Tregs for treating T2DM stroke. Furthermore, we utilized an optical imaging probe (IRD-αCD206) to target M2 macrophage/microglia cells and demonstrated its effect in visualizing M2 macrophage/microglia cells in vivo in ischemic brain tissue.

Intensified blood glucose treatment in diabetic patients undergoing a liver transplant: impact on graft evolution at 3 months and at 5 years

PURPOSE

The debate about the impact of intensified hyperglycemia treatment is still ranging. The main objective was to assess whether intensive glycemic control in hospitalized diabetic patients undergoing a liver transplant is associated with a lower rate of graft rejection at 3 months and at 5 years post-transplant.

METHODS

Cross-sectional study comparing a cohort of patients undergoing liver transplant in 2010 and 2011, in whom an intensive insulin protocol was applied, with a retrospective group of patients undergoing a liver transplant in 2005 and 2006, in whom a conventional insulin protocol was applied. Both diabetics and non-diabetics were compared. As intensive insulin therapy is applied mainly in diabetic patients, it is expected that, when comparing both periods, the treatment would only benefit those patients.

RESULTS

The logistic regression model showed a statistically significant interaction between the treatment group and the presence of diabetes for the rejection rate 3 months and 5 years post-transplant. At both time points, the intensive insulin treatment group had lower rejection rates in the case of diabetic patients, which did not occur in non-diabetic patients.

CONCLUSIONS

Our study shows a decrease in the rate of liver graft rejection in diabetic patients undergoing intensive insulin treatment.

Diabetes Mellitus and Liver Surgery: The Effect of Diabetes on Oxidative Stress and Inflammation

Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycaemia and high morbidity worldwide. The detrimental effects of hyperglycaemia include an increase in the oxidative stress (OS) response and an enhanced inflammatory response. DM compromises the ability of the liver to regenerate and is particularly associated with poor prognosis after ischaemia-reperfusion (I/R) injury. Considering the growing need for knowledge of the impact of DM on the liver following a surgical procedure, this review aims to present recent publications addressing the effects of DM (hyperglycaemia) on OS and the inflammatory process, which play an essential role in I/R injury and impaired hepatic regeneration after liver surgery.

Taiwanese Green Propolis Ethanol Extract Delays the Progression of Type 2 Diabetes Mellitus in Rats Treated with Streptozotocin/High-Fat Diet

Taiwanese green propolis ethanol extract (TGPE) is produced only in Taiwan and has a different composition from other types of propolis. TGPE is known for its anti-inflammation, anti-oxidation, and anti-microbial properties, but the effects and mechanisms of TGPE in the modulation of diabetes are unclear. In this study, we investigated the effects of TGPE on type 2 diabetes mellitus (T2DM) in a streptozotocin/high-fat-diet (STZ/HFD)-induced T2DM rat model. The results revealed that TGPE delayed the development and progression of T2DM and reduced the severity of β-cell failure. TGPE also attenuated inflammation and reactive oxygen species ROS in the rats. Moreover, there were higher levels of oxidant cytokines, leptin, and adiponectin in the serum of the TGPE-treated group. Unlike Brazilian propolis, TGPE promoted hepatic genes PPAR-α and CYP7A1, which were related to lipid catabolism and removal. TGPE may thus delay the progression of T2DM through anti-inflammation effects, anti-oxidation effects, and balancing lipid metabolism. It is suggested that TGPE can be a potential alternative medicine for T2DM.

Outcomes in patients with diabetes 10 years after liver transplantation

BACKGROUND

There are discrepancies between studies regarding the effect of diabetes mellitus on morbidity and mortality in patients undergoing liver transplantation. The aim of the present study was to compare mortality, risk of liver graft rejection, and cardiovascular events in patients with and without diabetes undergoing liver transplantation over a 10-year follow-up period.

METHODS

A retrospective study was performed on 183 patients who underwent liver transplantation in 2005 and 2006. Mortality and morbidity data were collected until 2016, including information on mortality and survival time, graft rejection and graft survival time, coronary heart disease, stroke, and peripheral arterial ischemia.

RESULTS

During the follow-up, 41.3% and 27.8% of patients in the groups with and without diabetes, respectively, died. A trend for lower survival time was observed in patients with diabetes, although this effect was not confirmed by the Cox regression model. There was an increased risk of graft rejection in the group with diabetes compared with the group without diabetes ( P  < 0.001). In the survival analysis, diabetes was associated with reduced graft survival time ( P  = 0.001). Cardiovascular events were also more likely in the group with diabetes ( P  = 0.005).

CONCLUSIONS

In the present study diabetes was associated with a higher risk of liver graft rejection and cardiovascular events. There was also a trend for higher mortality, although the effect was not statistically significant. These findings suggest that patients with diabetes require a more rigorous pretransplant evaluation and closer monitoring after transplantation in order to try to reduce associated complications.

Pre-existing diabetes is a risk factor for increased rates of cellular rejection after kidney transplantation: an observational cohort study

AIM

To investigate whether people with diabetes have an elevated risk of kidney allograft rejection in a well characterized clinical cohort in the setting of contemporary immunosuppression.

METHODS

We conducted a retrospective cohort study including all kidney allograft recipients at a single centre between 2007 and 2015, linking clinical, biochemical and histopathological data from electronic patient records.

RESULTS

Data were analysed for 1140 kidney transplant recipients. The median follow-up was 4.4 years post-transplantation, and 117 of the kidney transplant recipients (10.2%) had diabetes at time of transplantation. Kidney allograft recipients with vs without diabetes were older (53 vs 45 years; P<0.001) and more likely to be non-white (41.0% vs 26.4%; P=0.001). Kidney allograft recipients with vs without diabetes had a higher risk of cellular rejection (19.7% vs 12.4%; P=0.024), but not of antibody-mediated rejection (3.4% vs 3.7%; P=0.564). Graft function and risk of death-censored graft loss were similar in the two groups, but kidney allograft recipients with diabetes had a higher risk of death and overall graft loss than those without diabetes. In a Cox regression model of non-modifiable risk factors at time of transplantation, diabetes was found to be an independent risk factor for cellular rejection (hazard ratio 1.445, 95% CI 1.023-1.945; P=0.042).

CONCLUSIONS

Kidney allograft recipients with diabetes at transplantation should be counselled regarding their increased risk of cellular rejection but reassured regarding the lack of any adverse impact on short-to-medium term allograft function or survival.

Disease drivers of aging

It has long been known that aging, at both the cellular and organismal levels, contributes to the development and progression of the pathology of many chronic diseases. However, much less research has examined the inverse relationship-the contribution of chronic diseases and their treatments to the progression of aging-related phenotypes. Here, we discuss the impact of three chronic diseases (cancer, HIV/AIDS, and diabetes) and their treatments on aging, putative mechanisms by which these effects are mediated, and the open questions and future research directions required to understand the relationships between these diseases and aging.

Cerebral ischemic damage in diabetes: an inflammatory perspective

Stroke is one of the leading causes of death worldwide. A strong inflammatory response characterized by activation and release of cytokines, chemokines, adhesion molecules, and proteolytic enzymes contributes to brain damage following stroke. Stroke outcomes are worse among diabetics, resulting in increased mortality and disabilities. Diabetes involves chronic inflammation manifested by reactive oxygen species generation, expression of proinflammatory cytokines, and activation/expression of other inflammatory mediators. It appears that increased proinflammatory processes due to diabetes are further accelerated after cerebral ischemia, leading to increased ischemic damage. Hypoglycemia is an intrinsic side effect owing to glucose-lowering therapy in diabetics, and is known to induce proinflammatory changes as well as exacerbate cerebral damage in experimental stroke. Here, we present a review of available literature on the contribution of neuroinflammation to increased cerebral ischemic damage in diabetics. We also describe the role of hypoglycemia in neuroinflammation and cerebral ischemic damage in diabetics. Understanding the role of neuroinflammatory mechanisms in worsening stroke outcome in diabetics may help limit ischemic brain injury and improve clinical outcomes.

Reverse geroscience: how does exposure to early diseases accelerate the age-related decline in health?

Aging is the major risk factor for both the development of chronic diseases and loss of functional capacity. Geroscience provides links among the biology of aging, the biology of disease, and the physiology of frailty, three fields where enormous progress has been made in the last few decades. While, previously, the focus was on the role of aging in susceptibility to disease and disability, the other side of this relationship, which is the contribution of disease to aging, has been less explored at the molecular/cellular level. Indeed, the role of childhood or early adulthood exposure to chronic disease and/or treatment on accelerating aging phenotypes is well known in epidemiology, but the biological basis is poorly understood. A recent summit co-organized by the National Institutes of Health GeroScience Interest Group and the New York Academy of Sciences explored these relationships, using three chronic diseases as examples: cancer, HIV/AIDS, and diabetes. The epidemiological literature clearly indicates that early exposure to any of these diseases and/or their treatments results in an acceleration of the appearance of aging phenotypes, including loss of functional capacity and accelerated appearance of clinical symptoms of aging-related diseases not obviously related to the earlier event. The discussions at the summit focused on the molecular and cellular relationships between each of these diseases and the recently defined molecular and cellular pillars of aging. Two major conclusions from the meeting include the desire to refine an operational definition of aging and to concomitantly develop biomarkers of aging, in order to move from chronological to physiological age. The discussion also opened a dialogue on the possibility of improving late-life outcomes in patients affected by chronic disease by including age-delaying modalities along with the standard care for the disease in question.

Resuscitation Affects Microcirculatory Polymorphonuclear Leukocyte Behavior After Hemorrhagic Shock: Role of Hypertonic Saline and Pentoxifylline

We have previously shown that lung injury following fluid resuscitation either with hypertonic saline (HS) or lactated Ringer's (LR) plus pentoxifylline (PTX) attenuated acute lung injury when compared with LR resuscitation. The objective of the present study is to determine whether our previous observations are accompanied by changes in polymorphonuclear leukocyte (PMN) behavior. To study this, PMN-endothelial cell interactions, microcirculatory blood flow, lung histology, lung PMN infiltration (WIPO, Myeloperoxidase), and lung intracellular adhesion molecule-1 (ICAM-1) expression were assessed in a controlled hemorrhagic shock model followed by LR, HS, and LR+PTX resuscitation in rodents. Rats (240-300 g) were bled to a mean arterial pressure (MAP) of 35 mm Hg for 1 hr and then randomized into three groups: HS (7.5% NaCl, 4 ml/kg); LR (3× shed blood); and LR+PTX (25 mg/kg). Additionally, total shed blood was reinfused. A sham group underwent no shock and no treatment. The internal spermatic fascia was exteriorized and the microcirculation was observed by closed-circuit TV coupled to a microscope, 2 and 6 hrs after treatment. The number of leukocytes sticking to the venular endothelium was determined 2 hrs after fluid resuscitation. Microcirculatory blood flow was measured by an optical Doppler velocimeter. Lung histology and lung MPO immunostaining were assessed at 6 hrs, and lung ICAM-1 expression was determined by immunostaining at 2 hrs following fluid resuscitation. Two hours after treatment, HS (1.4 ± 0.4), LR+PTX (1.7 ± 0.3), and sham (0.4 ± 0.2) groups presented significant reductions in leukocyte adherence (cells/100 urn venule length), compared with the LR group (4.0 ± 0.9, P < 0.05). No differences were observed 6 hrs after treatment on leukocyte adherence and microcirculatory blood flow. ICAM-1 expression was significantly higher in LR- treated animals compared with the HS, LR+PTX, and sham groups (P < 0.01). PMN infiltration and overall lung injury were significantly attenuated by HS and LR+PTX. These results support earlier studies that indicated the potential application of HS and PTX in shock therapy and the increase in PMN- endothelial cell interaction and lung injury after LR resuscitation.

Tissue Kallikrein Alleviates Cerebral Ischemia-Reperfusion Injury by Activating the B2R-ERK1/2-CREB-Bcl-2 Signaling Pathway in Diabetic Rats

Diabetes mellitus (DM) substantially increases the risk of ischemic stroke and reduces the tolerance to ischemic insults. Tissue kallikrein (TK) has been demonstrated to protect neurons from ischemia/reperfusion (I/R) injury in orthoglycemic model by activating the bradykinin B2 receptor (B2R). Considering the differential effects of B2R or bradykinin B1 receptor (B1R) on cardioprotection and neuroprotection in I/R with or without diabetes, this study was designed to investigate the role of TK during cerebral I/R injury in streptozotocin-induced diabetic rats. Intravenous injection of TK inhibited apoptosis in neurons, alleviated edema and inflammatory reactions after focal cerebral I/R, significantly reduced the infarct volume, and improved functional recovery. These beneficial effects were accompanied by activation of the extracellular signal-regulated kinase 1/2 (ERK1/2), cAMP response element-binding (CREB), and Bcl-2 signal proteins. Inhibition of the B2R or ERK1/2 pathway abated the effects of TK, whereas an antagonist of B1R enhanced the effects. These findings reveal that the neuroprotective effect of TK against cerebral I/R injury in streptozotocin-induced diabetic rats mainly involves the enhancement of B2R and ERK1/2-CREB-Bcl-2 signaling pathway activity.

Angiotensin 1-7 significantly reduces diabetes-induced leukocyte recruitment both in vivo and in vitro

OBJECTIVE

Recent studies have demonstrated that Ang1-7 has anti-inflammatory effects. Since the formation of Ang1-7 is significantly altered in the setting of diabetes, here we aimed to evaluate whether Ang1-7 infusion could ameliorate diabetes-induced leukocyte recruitment.

METHODS

Wild-type male Wistar rats were randomly allocated to the following groups: control + saline, control + Ang1-7, diabetes + saline, diabetes + Ang1-7. Diabetes was induced by streptozotocin. Saline and Ang1-7 (576 μg/kg/day) were injected intraperitoneally daily. After 4 weeks leukocyte trafficking was studied in vivo by intravital microscopy in the mesenteric bed, where the expression of pro-oxidative, proinflammatory, and profibrotic molecules was also assessed. In parallel in vitro studies, HUVEC were grown in 5 mM, 22 mM, 30 mM, 40 mM, 50 mM, and 75 mM glucose media for 48 h, 72 h and 6 days and were treated either with placebo, or with Ang1-7, or with Ang1-7 and its inhibitor A779 in order to evaluate the expression of ICAM-1 and VCAM-1. We further studied leukocytes recruitment in vitro by evaluating PMN-HUVEC adhesion.

RESULTS

Ang1-7 prevented in vivo diabetes-induced leukocyte adhesion and extravasation, and it significantly reduced vascular hypertrophy and the other molecular changes due to diabetes. Ang 1-7 prevented also in vitro the hyperglycemia-induced increase of ICAM-1 and VCAM-1 as well as the hyperglycemia-induced PMN adhesion. A779 inhibited Ang 1-7 effects.

CONCLUSIONS

Ang1-7 significantly reduced diabetes-induced leukocyte recruitment both in vivo and in vitro. These findings emphasize the potential utility of ACE2/Ang1-7/Mas repletion as a strategy to reduce diabetes-induced atherosclerosis.

Cellular connections, microenvironment and brain angiogenesis in diabetes: Lost communication signals in the post-stroke period

Diabetes not only increases the risk but also worsens the motor and cognitive recovery after stroke, which is the leading cause of disability worldwide. Repair after stroke requires coordinated communication among various cell types in the central nervous system as well as circulating cells. Vascular restoration is critical for the enhancement of neurogenesis and neuroplasticity. Given that vascular disease is a major component of all complications associated with diabetes including stroke, this review will focus on cellular communications that are important for vascular restoration in the context of diabetes. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.

Decelerated vascularization in tissue-engineered constructs in association with diabetes mellitus in vivo

AIMS

Rapid blood vessel ingrowth in transplanted tissue engineering constructs is the key factor for successful incorporation, but many potential patients who may use engineered tissues suffer from widespread diseases that limit the capacity of neovascularization (e.g. diabetes). Thus, in vivo vascularization analyses of tissue-engineered constructs in angiogenically affected organisms are required.

METHODS

We therefore investigated the in vivo incorporation of collagen-coated and cell-seeded poly-L-lactide-co-glycolide scaffolds in diabetic B6.BKS(D)-Lepr(db)/J mice using repetitive intravital fluorescence microscopy over a time period of two weeks. For this purpose, scaffolds were seeded with osteoblast-like or bone marrow mesenchymal stem cells and implanted into the dorsal skinfold chambers of diabetic and non-diabetic (C57BL/6) mice.

RESULTS

Apart from slightly increased inflammatory parameters, diabetic mice showed significantly reduced capillary densities compared with non-diabetic animals from day 6 onward. In line with previous studies, more densely meshed microvascular networks were demonstrated in cell-seeded than in collagen-coated scaffolds from day 6 onward within the single groups (diabetic and control).

CONCLUSIONS

A large number of patients who suffer from systemic diseases that affect angiogenesis would profit from tissue engineering. Therefore, the challenge for the clinical introduction of tissue-engineered constructs will be to overcome the decreased angiogenesis in diabetic organisms.

Platelets, acting in part via P-selectin, mediate cytomegalovirus-induced microvascular dysfunction

Cytomegalovirus (CMV) infects a majority of the population worldwide. It has been implicated in cardiovascular disease, induces microvascular dysfunction, and synergizes with hypercholesterolemia to promote leukocyte and platelet recruitment in venules. Although platelets and platelet-associated P-selectin contribute to cardiovascular disease inflammation, their role in CMV-induced vascular responses is unknown. We assessed the role of platelets in CMV-induced microvascular dysfunction by depleting platelets and developing bone marrow chimeric mice deficient in platelet P-selectin. Wild-type and chimeric mice received mock or murine (m)CMV intraperitoneally. Five weeks later, some mice were switched to a high-cholesterol diet (HC) to investigate the synergism between mCMV and HC. Arteriolar vasodilation and recruitment of leukocytes and donor platelets in venules were measured at 11wk. mCMV with or without HC caused significant endothelial dysfunction in arterioles. Platelet depletion restored normal vasodilation in mCMV-HC but not mCMV-ND mice, whereas protection was seen in both groups for platelet P-selectin chimeras. Only mCMV + HC elevated leukocyte and platelet recruitment in venules. Leukocyte adhesion was reduced to mock levels by acute platelet depletion but was only partially decreased in platelet P-selectin chimeras. Platelets from mCMV-HC mice and, to a lesser extent, mCMV-ND but not mock-HC mice showed significant adhesion in mCMV-HC recipients. Our findings implicate a role for platelets, acting through P-selectin, in CMV-induced arteriolar dysfunction and suggest that the addition of HC leads to a platelet-dependent, inflammatory infiltrate that is only partly platelet P-selectin dependent. CMV appeared to have a stronger activating influence than HC on platelets and may represent an additional therapeutic target in vulnerable patients.

Rodent animal models: from mild to advanced stages of diabetic nephropathy

Diabetic nephropathy (DN) is a secondary complication of both type 1 and type 2 diabetes, resulting from uncontrolled high blood sugar. 30-40% of diabetic patients develop DN associated with a poor life expectancy and end-stage renal disease, causing serious socioeconomic problems. Although an exact pathogenesis of DN is still unknown, several factors such as hyperglycemia, hyperlipidemia, hypertension and proteinuria may contribute to the progression of renal damage in diabetic nephropathy. DN is confirmed by measuring blood urea nitrogen, serum creatinine, creatinine clearance and proteinuria. Clinical studies show that intensive control of hyperglycemia and blood pressure could successfully reduce proteinuria, which is the main sign of glomerular lesions in DN, and improve the renal prognosis in patients with DN. Diabetic rodent models have traditionally been used for doing research on pathogenesis and developing novel therapeutic strategies, but have limitations for translational research. Diabetes in animal models such as rodents are induced either spontaneously or by using chemical, surgical, genetic, or other techniques and depicts many clinical features or related phenotypes of the disease. This review discusses the merits and demerits of the models, which are used for many reasons in the research of diabetes and diabetic complications.

[Complications associated with hyperglycemia in liver transplant patients]

BACKGROUND

Hyperglycemia is a frequent phenomenon in hospitalized patients that is associated with negative outcomes. It is common in liver transplant patients as a result of stress and is related to immunosuppressant drugs. Although studies are few, a history of diabetes and the presentation of hyperglycemia during liver transplantation have been associated with a higher risk for rejection.

AIMS

To analyze whether hyperglycemia during the first 48hours after liver transplantation was associated with a higher risk for infection, rejection, or longer hospital stay.

METHODS

A retrospective cohort study was conducted on patients above the age of 15years that received a liver transplant. Hyperglycemia was defined as a value above 140mg/dl and it was measured in three different manners (as an isolated value, as a mean value, and as a weighted value over time). The relation of hyperglycemia to a risk for acute rejection, infection, or longer hospital stay was evaluated.

RESULTS

Some form of hyperglycemia was present in 94% of the patients during the first 48 post-transplantation hours, regardless of its definition. There was no increased risk for rejection (OR: 1.49; 95%CI: 0.55-4.05), infection (OR: 0.62; 95%CI: 0.16-2.25), or longer hospital stay between the patients that presented with hyperglycemia and those that did not.

CONCLUSIONS

Hyperglycemia during the first 48hours after transplantation appeared to be an expected phenomenon in the majority of patients and was not associated with a greater risk for rejection or infection and it had no impact on the duration of hospital stay.

Animal models of stroke: translational potential at present and in 2050

Translation from basic science bench research in ischemic stroke to bedside treatment of patients suffering ischemic stroke remains a difficult challenge. Despite literally hundreds of compounds and interventions that provide benefit in experimental models of cerebral ischemia, efficacy in humans remains to be demonstrated. The reasons for failure to translate the extensive positive basic science findings to successful clinical trials have been the focus of discussion for years. Some attribute the failure to flaws in clinical trial design, others question the predictive value of current animal models and some question the quality of preclinical data. It is likely that a combination of all these shortcomings have ultimately led to the failure. The purpose of this review is to analyze the commonly used animal models used in the field today, provide a framework for understanding the current state of basic science research in the ischemic stroke field and discuss a path forward.

Adrenomedullin deficiency and aging exacerbate ischemic white matter injury after prolonged cerebral hypoperfusion in mice

Adrenomedullin was originally isolated from pheochromocytoma cells and reduces insulin resistance by decreasing oxidative stress. White matter lesions induced by aging and hyperglycemia play a crucial role in cognitive impairment in poststroke patients. Here, we examine whether adrenomedullin deficiency and aging exacerbate ischemic white matter injury after prolonged cerebral hypoperfusion. Adrenomedullin heterozygous, wild-type young/aged mice were subjected to prolonged hypoperfusion. Prolonged cerebral hypoperfusion followed by immunohistochemical analysis was used to evaluate white matter injury. After prolonged hypoperfusion, white matter damage progressed in a time-dependent manner in AM^+/− group compared with the wild-type group. The number of oligodendrocyte progenitor cells gradually increased after prolonged hypoperfusion, whereas oligodendrocytes decreased following a transient increase, but the ratio of increase was mild in the AM^+/− group (P < 0.05). Oxidative stress was detected in oligodendrocytes, with a larger increase in the AM^+/− group (P < 0.05). Aged mice showed the same tendency, but white matter damage was worse, especially in the aged AM^+/− group. Our results demonstrated that white matter injury was increased in adrenomedullin deficiency, which induced oxidative stress. White matter injury was more exacerbated because of hyperglycemia in aged AM^+/− group. Adrenomedullin may be an important target in the control of ischemic white matter injury.

Observation of mesenteric microcirculatory disturbance in rat by laser oblique scanning optical microscopy

Ischemia-reperfusion (I/R) injury model has been widely applied to the study of microcirculation disturbance. In this work, we used laser oblique scanning optical microscopy (LOSOM) to observe the microcirculation system in the mesentery of rat model. Utilizing a localized point-scanning detection scheme, high-contrast images of leukocytes were obtained. The extended detection capability facilitated both the automatic in vivo cell counting and the accurate measurement of the rolling velocity of leukocytes. Statistical analysis of the different treatment groups suggested that the distinction between I/R and sham groups with time lapse is significant.

mRNA redistribution during permanent focal cerebral ischemia

Translation arrest occurs in neurons following focal cerebral ischemia and is irreversible in penumbral neurons destined to die. Following global cerebral ischemia, mRNA is sequestered away from 40S ribosomal subunits as mRNA granules, precluding translation. Here, we investigated mRNA granule formation using fluorescence in situ histochemistry out to 8 h permanent focal cerebral ischemia using middle cerebral artery occlusion in Long Evans rats with and without diabetes. Neuronal mRNA granules colocalized with PABP, HuR, and NeuN, but not 40S or 60S ribosomal subunits, or organelle markers. The volume of brain with mRNA granule-containing neurons decreased exponentially with ischemia duration, and was zero after 8 h permanent focal cerebral ischemia or any duration of ischemia in diabetic rats. These results show that neuronal mRNA granule response has a limited range of insult intensity over which it is expressed. Identifying the limits of effective neuronal stress response to ischemia will be important for developing effective stroke therapies.

Diabetes alters the expression of partial vasoactivators in cerebral vascular disease susceptible regions of the diabetic rat

BACKGROUND

The pathogenesis between cerebral vascular disease (CVD) and the endothelial dysfunction (ETD) remains elusive in diabetes. Therefore, we investigated the expression of partial vasoactivators which be closely relative to ETD in CVD susceptible brain regions in the diabetic rat. The aim was to search some possible pathogenesis.

METHODS

Diabetes was induced by a single intraperitoneal injection of streptozotocin and a high lipid/sugar diet. The expression of vasoactivators ET-1, CGRP, VCAM-1, ICAM-1 and P-selectin were assessed by immunohistochemical staining and measurement of optic density of positive cells in the frontal and temporal lobe, basal ganglia and thalamus at 4 weeks after establishment of the diabetic model.

RESULTS

The expression of ET-1, VCAM-1, ICAM-1 and P-selectin significantly increased and CGRP significantly decreased in the diabetic group, and the expression of these vasoactivators was significantly different among the frontal, temporal lobe, basal ganglia and thalamus, and among the emotion, splanchno-motor and neuroendocrine center in the diabetic group.

CONCLUSIONS

Diabetes alters the expression of partial vasoactivators in cerebral vascular disease susceptible regions of the diabetic rat. Therefore, we suggested that CVD complications in diabetes are partly caused by ETD via an imbalance expression of endothelial vasoactivators, which might be associated with dysfunction of emotion, autonomic nerve and endocrine center. However, further studies are warranted.

Human leukocyte/endothelial cell interactions and mitochondrial dysfunction in type 2 diabetic patients and their association with silent myocardial ischemia

OBJECTIVE

Diabetes is associated with oxidative stress and increased mortality, but a possible correlation between leukocyte-endothelium interactions, oxidative stress, and silent myocardial ischemia (SMI) is yet to be confirmed.

RESEARCH DESIGN AND METHODS

Mitochondrial dysfunction and interactions between leukocytes and human umbilical vein endothelial cells were evaluated in 200 type 2 diabetic patients (25 with SMI) and 60 body composition- and age-matched control subjects. A possible correlation between these parameters and the onset of SMI was explored, and anthropometric and metabolic parameters were also analyzed.

RESULTS

Waist, levels of triglycerides, proinflammatory cytokines (interleukin-6 and tumor necrosis factor-α), HbA1c, high-sensitivity C-reactive protein (hs-CRP), glucose, and insulin, and homeostasis model assessment of insulin resistance were higher in diabetic patients than in control subjects. However, no statistical differences in hs-CRP and insulin levels were detected when the data were adjusted for waist. None of these parameters varied between SMI and non-SMI patients. Mitochondrial function was impaired and leukocyte-endothelium interactions were more frequent among diabetic patients, which was evident in the lower mitochondrial O2 consumption, membrane potential, polymorphonuclear cell rolling velocity, and GSH/GSSG ratio, and in the higher mitochondrial reactive oxygen species production and rolling flux, adhesion, and vascular cell adhesion molecule-1 (VCAM-1) and E-selectin molecules observed in these subjects. Moreover, these differences correlated with SMI. Statistical differences were maintained after adjusting the data for BMI and waist, with the exception of VCAM-1 levels when adjusted for waist.

CONCLUSIONS

Oxidative stress, mitochondrial dysfunction, and endothelium-inducing leukocyte-endothelium interactions are features of type 2 diabetes and correlate with SMI.

Hyperglycemia as a Risk Factor of Ischemic Stroke

Diabetes is considered a major risk factor for stroke and is associated with worsened stroke outcomes. Here, we discuss and summarize the mechanisms that have been associated with the increased risk of stroke due to the hyperglycemia in diabetes mellitus. In diabetic stroke models, hyperglycemia exaggerates the following damaging processes: acidosis, accumulation of reactive oxygen species/reactive nitrogen, inflammation and mitochondrial dysfunction. Understanding the mechanism of diabetes acting as a stroke risk factor will definitely assist to reveal issues related to drug metabolism and toxicity in diabetic stroke. In addition, it is suggested that future studies may focus on the mechanisms mediating blood-brain barrier and astrocytes dysfunction under hyperglycemic stroke.

The Influence of Stroke Risk Factors and Comorbidities on Assessment of Stroke Therapies in Humans and Animals

The main driving force behind the assessment of novel pharmacological agents in animal models of stroke is to deliver new drugs to treat the human disease rather than to increase knowledge of stroke pathophysiology. There are numerous animal models of the ischaemic process and it appears that the same processes operate in humans. Yet, despite these similarities, the drugs that appear effective in animal models have not worked in clinical trials. To date, tissue plasminogen activator is the only drug that has been successfully used at the bedside in hyperacute stroke management. Several reasons have been put forth to explain this, but the failure to consider comorbidities and risk factors common in older people is an important one. In this article, we review the impact of the risk factors most studied in animal models of acute stroke and highlight the parallels with human stroke, and, where possible, their influence on evaluation of therapeutic strategies.

Increased recruitment but impaired function of leukocytes during inflammation in mouse models of type 1 and type 2 diabetes

Background

Patients suffering from diabetes show defective bacterial clearance. This study investigates the effects of elevated plasma glucose levels during diabetes on leukocyte recruitment and function in established models of inflammation.

Methodology/Principal Findings

Diabetes was induced in C57Bl/6 mice by intravenous alloxan (causing severe hyperglycemia), or by high fat diet (moderate hyperglycemia). Leukocyte recruitment was studied in anaesthetized mice using intravital microscopy of exposed cremaster muscles, where numbers of rolling, adherent and emigrated leukocytes were quantified before and during exposure to the inflammatory chemokine MIP-2 (0.5 nM). During basal conditions, prior to addition of chemokine, the adherent and emigrated leukocytes were increased in both alloxan- (62±18% and 85±21%, respectively) and high fat diet-induced (77±25% and 86±17%, respectively) diabetes compared to control mice. MIP-2 induced leukocyte emigration in all groups, albeit significantly more cells emigrated in alloxan-treated mice (15.3±1.0) compared to control (8.0±1.1) mice. Bacterial clearance was followed for 10 days after subcutaneous injection of bioluminescent S. aureus using non-invasive IVIS imaging, and the inflammatory response was assessed by Myeloperoxidase-ELISA and confocal imaging. The phagocytic ability of leukocytes was assessed using LPS-coated fluorescent beads and flow cytometry. Despite efficient leukocyte recruitment, alloxan-treated mice demonstrated an impaired ability to clear bacterial infection, which we found correlated to a 50% decreased phagocytic ability of leukocytes in diabetic mice.

Conclusions/Significance

These results indicate that reduced ability to clear bacterial infections observed during experimentally induced diabetes is not due to reduced leukocyte recruitment since sustained hyperglycemia results in increased levels of adherent and emigrated leukocytes in mouse models of type 1 and type 2 diabetes. Instead, decreased phagocytic ability observed for leukocytes isolated from diabetic mice might account for the impaired bacterial clearance.

Increased susceptibility to ischemia and macrophage activation in STZ-diabetic rat nerve

Ischemic vulnerability in diabetic nerve plays a paramount role in the development of diabetic neuropathy, yet little is known of the underlying mechanism. Diabetes enhances the inflammatory response to ischemia and reperfusion. We investigated pathological characteristics of nerve fibers and endoneurial macrophages along the length of sciatic-tibial nerves before and after ischemia (60 to 90 min) and reperfusion (6h to 7 days) in 8 weeks of STZ-induced diabetic rats. Without ischemia, diabetic nerves revealed significantly increased the density of Iba-1-positive endoneurial macrophages when compared with controls. Most of macrophages appeared slim and triangular in shape, but in diabetic nerves, some were rounded with bromodeoxyuridine (BrdU) incorporation, suggesting proliferating macrophages. Seventy-five minutes of ischemia is the minimal ischemic time to cause pathological changes in diabetic nerves. Following 90 min of ischemia and 6h of reperfusion in diabetic rats, the number of Iba-1-positive endoneurial macrophages was increased significantly at the thigh level of sciatic nerve when compared with those before ischemia. Endoneurial macrophages in diabetic nerves increased in number further significantly after 24 and 48 h of reperfusion and underwent morphological alterations; swollen and rounded including phagocytosis. After 90 min of ischemia and 7 days of reperfusion, severe pathological alterations, e.g., demyelination and endoneurial edema at proximal nerves and axonal degeneration distally, were observed in diabetic nerves, while control nerves showed normal morphology. We conclude that macrophage proliferation occurs in STZ-diabetic nerves. The acute inflammatory response after ischemia and reperfusion was intensified in diabetic nerves. Activation of resident macrophages and infiltration by recruited macrophages could be casually linked to ischemic susceptibility in diabetic nerve.

Effect of plant neutrophil elastase inhibitor on leucocyte migration, adhesion and cytokine release in inflammatory conditions

BACKGROUND AND PURPOSE

The serine and cysteine peptidase inhibitor, BbCI, isolated from Bauhinia bauhinioides seeds, is similar to the classical plant Kunitz inhibitor, STI, but lacks disulphide bridges and methionine residues. BbCI blocks activity of the serine peptidases, elastase (K(iapp) 5.3 nM) and cathepsin G (K(iapp) 160.0 nM), and the cysteine peptidase cathepsin L (K(iapp) 0.2 nM). These three peptidases play important roles in the inflammatory process.

EXPERIMENTAL APPROACH

We measured the effects of BbCI on paw oedema and on leucocyte accumulation in pleurisy, both induced by carrageenan. Leucocyte-endothelial cell interactions in scrotal microvasculature in Wistar rats were investigated using intravital microscopy. Cytokine levels in pleural exudate and serum were measured by elisa.

KEY RESULTS

Pretreatment of the animals with BbCI (2.5 mg·kg(-1)), 30 min before carrageenan-induced inflammation, effectively reduced paw oedema and bradykinin release, neutrophil migration into the pleural cavity. The number of rolling, adhered and migrated leucocytes at the spermatic fascia microcirculation following carrageenan injection into the scrotum were reduced by BbCI pretreatment. Furthermore, levels of the rat chemokine cytokine-induced neutrophil chemo-attractant-1 were significantly reduced in both pleural exudates and serum from animals pretreated with BbCI. Levels of interleukin-1β or tumour necrosis factor-α, however, did not change.

CONCLUSIONS AND IMPLICATIONS

Taken together, our data suggest that the anti-inflammatory properties of BbCI may be useful in investigations of other pathological processes in which human neutrophil elastase, cathepsin G and cathepsin L play important roles.

Early microvascular complications of prediabetes in mice with impaired glucose tolerance and dyslipidemia

Microvascular complications are an important cause of morbidity in diabetic patients and can be detected in a significant number of patients at the time of diabetes diagnosis. However, little is known about the alterations in the microvasculature previous to the clinical manifestation of diabetes mellitus type 2. To obtain more insights into the early microvascular deterioration resulting from prediabetes, morphological and functional microvascular parameters were monitored using intravital fluorescence microscopy through a dorsal skin-fold chamber preparation in the uncoupling promotor-driven diphtheria toxin A chain (UCP1/DTA) mice. At the age of 12 weeks, the UCP1/DTA-mice were characterized by impaired glucose tolerance with concurrent unchanged fasting glucose, as well as dyslipidemia, hyperinsulinemia, hypertension and obesity. Prediabetic mice displayed combined hypertriglyceridemia and hypercholesterinemia. Associated with these prediabetic metabolic alterations, we demonstrate that microvascular density showed a dramatic decrease due to a reduction in perfused small vessels. A reduction in vascular density combined with unaltered blood flow in single vessels resulted in impaired tissue perfusion. Endothelial dysfunction with subsequently increased microvascular permeability and leukocyte-endothelium interactions were found. Our results of profound microvascular alterations at stages of normal fasting glucose underline the importance of early screening for prediabetes and associated microvascular complications.

Cytomegalovirus infection leads to microvascular dysfunction and exacerbates hypercholesterolemia-induced responses

Cytomegalovirus (CMV) persistently infects more than 60% of the worldwide population. In immunocompetent hosts, it has been implicated in several diseases, including cardiovascular disease, possibly through the induction of inflammatory pathways. Cardiovascular risk factors promote an inflammatory phenotype in the microvasculature long before clinical disease is evident. This study determined whether CMV also impairs microvascular homeostasis and synergizes with hypercholesterolemia to exaggerate these responses. Intravital microscopy was used to assess endothelium-dependent and -independent arteriolar vasodilation and venular leukocyte and platelet adhesion in mice after injection with either mock inoculum or murine CMV (mCMV). Mice were fed a normal (ND) or high-cholesterol (HC) diet beginning at 5 weeks postinfection (p.i.), or a HC diet for the final 4 weeks of infection. mCMV-ND mice exhibited impaired endothelium-dependent vasodilation versus mock-ND at 9 and 12 weeks and endothelium-independent arteriolar dysfunction by 24 weeks. Transient mild leukocyte adhesion occurred in mCMV-ND venules at 7 and 21 weeks p.i. HC alone caused temporary arteriolar dysfunction and venular leukocyte and platelet recruitment, which were exaggerated and prolonged by mCMV infection. The time of introduction of HC after mCMV infection determined whether mCMV+HC led to worse venular inflammation than either factor alone. These findings reveal a proinflammatory influence of persistent mCMV on the microvasculature, and suggest that mCMV infection enhances microvasculature susceptibility to both inflammatory and thrombogenic responses caused by hypercholesterolemia.

Different strokes for different folks: the rich diversity of animal models of focal cerebral ischemia

No single animal model is able to encompass all of the variables known to affect human ischemic stroke. This review highlights the major strengths and weaknesses of the most commonly used animal models of acute ischemic stroke in the context of matching model and experimental aim. Particular emphasis is placed on the relationships between outcome and underlying vascular variability, physiologic control, and use of models of comorbidity. The aim is to provide, for novice and expert alike, an overview of the key controllable determinants of experimental stroke outcome to help ensure the most effective application of animal models to translational research.

Microvascular responses to cardiovascular risk factors

Hypertension, hypercholesterolemia, diabetes, and obesity are among a growing list of conditions that have been designated as major risk factors for cardiovascular disease (CVD). While CVD risk factors are well known to enhance the development of atherosclerotic lesions in large arteries, there is also evidence that the structure and function of microscopic blood vessels can be profoundly altered by these conditions. The diverse responses of the microvasculature to CVD risk factors include oxidative stress, enhanced leukocyte- and platelet-endothelial cell adhesion, impaired endothelial barrier function, altered capillary proliferation, enhanced thrombosis, and vasomotor dysfunction. Emerging evidence indicates that a low-grade systemic inflammatory response that results from risk factor-induced cell activation and cell-cell interactions may underlie the phenotypic changes induced by risk factor exposure. A consequence of the altered microvascular phenotype and systemic inflammatory response is an enhanced vulnerability of tissues to the deleterious effects of secondary oxidative and inflammatory stresses, such as ischemia and reperfusion. Future efforts to develop therapies that prevent the harmful effects of risk factor-induced inflammation should focus on the microcirculation.

Role of blood cells in ischaemia-reperfusion induced endothelial barrier failure

Ischaemia and reperfusion (I/R) elicits an acute inflammatory response that is characterized by the recruitment of inflammatory cells, oxidative stress, and endothelial barrier failure. Over the past three decades, much progress has been made in our understanding of the mechanisms that underlie the inflammatory response and microvascular dysfunction associated with I/R. This review is focused on the role of leucocytes (neutrophils and T-lymphocytes) and platelets, and their activation products, as mediators of I/R-induced endothelial barrier failure. The contributions of cytokines, chemokines, and oxidative stress to I/R-induced barrier dysfunction are also discussed. It concludes with an analysis of how risk factors for cardiovascular disease, i.e. hypertension, diabetes, hypercholesterolaemia, and obesity, influence the vascular permeability response to I/R. Areas of uncertainty and controversy in this field of investigation are also identified.

The accelerated post-infarction progression of cardiac remodelling is associated with genetic changes in an untreated streptozotocin-induced diabetic rat model

AIMS

The mechanism by which diabetes mellitus exacerbates myocardial injury and the incidence of heart failure after acute myocardial infarction (AMI), remains unclear. We studied the severity of cardiac dysfunction and time-dependent gene expression in a hyperglycaemic rat model with AMI.

METHODS AND RESULTS

The diabetic model was produced by injection of streptozotocin in Sprague-Dawley rats. Ten weeks after induction of diabetes, AMI was induced by ligation of the left anterior descending coronary artery. Cardiac function and left ventricular (LV) dimensions were evaluated using two-dimensional echocardiography. Structural changes were assessed by histological examination. Gene expression profile was documented by using affymetrix genechip U230 2.0 array and real time-PCR. During 56 days post-AMI, lower survival rates, worse LV function, more severe fibrosis, and larger LV diameters were identified in diabetic rats compared with non-diabetic rats. A total 1221 genes involved in processes, such as glucose metabolism, fatty acid metabolism, extracellular matrix, and apoptosis, were found to be differentially expressed between diabetic and non-diabetic rats, of these 770 were up-regulated and 451 down-regulated. Up-regulation of the genes was found 1-2 weeks earlier in diabetic rats than in non-diabetic rats.

CONCLUSION

The present data suggest that hyperglycaemia up-regulates remodelling-related genes, which may be responsible for the worse outcomes in diabetics than in non-diabetics after AMI.

Glycemic control and organ transplantation

A discussion of hyperglycemia during organ transplantation is a broad topic that includes patients with a known history of diabetes pretransplant, those at risk for post-transplant diabetes, those with stress-induced hyperglycemia, those with hyperglycemia related to immunosuppressive therapy, and hyperglycemia in the deceased organ donor. In contrast to the plethora of articles and studies describing perioperative and critical care management of hyperglycemia in cardiac, trauma, and medical/surgical intensive care unit patients, relatively few published articles in the field of organ transplantation can be found. This article consists of a review of available literature in the form of publications and abstracts, and a preliminary report of the authors' work with liver transplantation and deceased organ donors.

TNF-alpha is an independent serum marker for proliferative retinopathy in type 1 diabetic patients

PURPOSE

This study aimed to determine if there are any associations between serum levels of inflammatory markers and proliferative retinopathy (PDR) in type 1 diabetic patients.

DESIGN

A cross-sectional design was utilized for this study.

METHODS

One hundred twenty-eight type 1 diabetic patients underwent stereo fundus photography according to the Early Treatment Diabetic Retinopathy Study and were divided into two retinopathy groups: no or nonproliferative retinopathy (NDR/NPDR; n=62) and PDR (n=66). Serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta, IL-6, soluble vascular cellular adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), P-selectin, and high-sensitivity C-reactive protein (hsCRP) were analyzed. Statistical analysis was performed using nonparametric Mann-Whitney U test and multivariate logistic regression analysis.

RESULTS

Patients with PDR had higher levels of TNF-alpha [7.0 pg/ml (<4-17) vs. 6.0 pg/ml (<4-25); P=.009], sVCAM-1 [860 ng/ml (360-2120) vs. 700 ng/ml (310-1820); P<.001], and P-selectin [180 ng/ml (39-400) vs. 150 ng/ml (42-440); P=.017; figures are expressed as median (range)]. There were no differences in serum levels of sICAM-1 or hsCRP. IL-1 beta was not detectable in any patient, and IL-6 was detectable in only 22.7% of the patients. In multivariate logistic regression analysis, TNF-alpha was the single, persistent, independent determinant inflammatory marker for PDR.

CONCLUSION

The association between TNF-alpha and PDR in type 1 diabetic patients suggests that inflammation might play a role in the pathogenesis of proliferative diabetic retinopathy.

A Global Assessment of the Inflammatory Response Elicited Upon Open Abdominal Aortic Aneurysm Repair

The inflammatory response during elective open infrarenal abdominal aortic aneurysm repair and its impact on outcome is investigated. Twenty high-risk patients were enrolled, and blood samples were obtained at 8 perioperative time points. Endotoxin, cytokines (tumor necrosis factor-α and interleukin-1β, and interleukin-6), CD11b expression, and nitric oxide were measured. Peak endotoxin levels occurred within 30 minutes of reperfusion and were higher among patients developing complications. Interleukin-6 levels increased during reperfusion, reaching a peak on the first postoperative day. Interleukin-6 increase correlated with aortic clamp time and morbidity. CD11b expression increased 30 minutes after reperfusion, and this effect was greater among patients who developed complications. Endotoxin may be important in the pathogenesis of multiple organ dysfunction syndrome. Activated neutrophils may have a central role in tissue injury after reperfusion. Intraoperative CD11b upregulation may be an early marker for postoperative complications after infrarenal abdominal aortic aneurysm repair.

Association of hyperglycemia on allograft function in the early period after renal transplantation

Hyperglycemia is common following renal transplantation. This study was conducted to evaluate the relationship of perioperative serum glucose levels and acute rejection in 100 nondiabetic patients who underwent renal transplantation. Blood glucose was measured immediately following surgery and every 6 hours during the first 48 hours posttransplant as well as for 1 month to evaluate occurrence of acute rejection episodes (ARE). The rate of ARE was 33%. The mean blood glucose level immediately after surgery in patients with versus without ARE was 249.67 +/- 61.78 and 184.82 +/- 73.35 mg/dL, respectively (P=.000). There was no significant correlation between ARE and donor or recipient age or sex, delayed graft function, type of donor, or treatment. This study suggested a correlation between immediate blood glucose and ARE. In this regard, blood glucose monitoring and control during operation and immediate postoperatively may reduce the acute rejection rate.

Hyperglycemia is a major determinant of albumin permeability in diabetic microcirculation: the role of mu-calpain

Increased permeability to albumin is a well-known feature of diabetic microvasculature and a negative prognostic factor of vascular complications. The mechanisms responsible for loss of the physiological albumin barrier in diabetic organs remain only partially understood. We have recently demonstrated that the protease mu-calpain is activated in hyperglycemia, which causes endothelial dysfunction and vascular inflammation. In the present study, we investigated whether mu-calpain is involved in the hyperpermeability of the diabetic vasculature. We also investigated the mechanistic roles of hyperglycemia and leukocyte adhesion in this process. Albumin permeability in the intact microcirculation of the Zucker diabetic fatty (ZDF) rat was quantified by intravital microscopy. Extravasation of albumin in the microcirculation of ZDF rats was significantly increased when compared with nondiabetic Zucker lean (ZL) rats. Microvascular albumin leakage was prevented by either antisense depletion of mu-calpain or pharmacological inhibition of calpain in vivo. Calpain inhibition also attenuated urinary albumin excretion in ZDF rats. Glucose concentrations in the range of those found in the blood of ZDF rats increased albumin permeability in nondiabetic ZL rats. Thus, this demonstrates a mechanistic role for hyperglycemia in the hypermeability of diabetes. Depletion of polymorphonuclear leukocytes in vivo failed to prevent glucose-induced hypermeability, which suggests that hyperglycemia can disrupt the physiological endothelial cell barrier of the microcirculation, even in the absence of increased overt leukocyte-endothelium interactions.