Validating a Dimensionless Number for Glucose Homeostasis in Humans

Understanding type 2 diabetes is challenged by the diversity of patient phenotypes. Translating data across species and among individuals is a barrier for understanding the genetic loci that underpin this multifactorial disease. Dynamic scaling, based upon dimensional analysis, is a common technique in engineering used to translate data among different systems. The objective of this study was to gain insight using dimensional analysis into the relative changes in insulin production capacity vs. insulin-dependent glucose metabolism in patient groups that represent distinct stages of disease progression. A dimensionless number was derived using variables involved in the production of insulin and in the sensitivity of glucose metabolism to insulin. The resulting dynamic scaling relationship was validated against patient data obtained for over 2000 individuals that range in phenotype from normal to severe type 2 diabetes. Individuals were identified in the third National Health and Nutrition Evaluation Survey. Patient groups clustered in different regions based upon the severity of clinical symptoms. The cross-sectional comparison among patient groups shows that progression from normal to clinical onset of type 2 diabetes exhibits a non-linear change in the ratio of insulin production to insulin-dependent glucose metabolism: normals are balanced, pre-diabetic individuals exhibit an increase, and individuals with clinical type 2 diabetes exhibit a decrease in this ratio. This dimensionless number provides a method for discriminating between patient groups from first principles. By analogy with other dimensionless numbers, this number may be used to monitor basic physiological variables responsible for glucose homeostasis. In addition, a similar dynamic trajectory to the clinical populations could provide a criterion for selecting relevant animal models for diabetes. Electronic supplementary material  The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

Recombinant Pregnancy-Specific Glycoprotein 1 Has a Protective Role in a Murine Model of Acute Graft-versus-Host Disease

Acute graft-versus-host disease (aGVHD) is an immune-mediated reaction that can occur after hematopoietic stem cell transplantation in which donor T cells recognize the host antigens as foreign, destroying host tissues. Establishment of a tolerogenic immune environment while preserving the immune response to infectious agents is required for successful bone marrow transplantation. Pregnancy-specific glycoprotein 1 (PSG1), which is secreted by the human placenta into the maternal circulation throughout pregnancy, likely plays a role in maintaining immunotolerance to prevent rejection of the fetus by the maternal immune system. We have previously shown that PSG1 activates the latent form of transforming growth factor β1 (TGF-β), a cytokine essential for the differentiation of tolerance-inducing CD4⁺FoxP3⁺ regulatory T cells (Tregs). Consistent with this observation, treatment of naïve murine T cells with PSG1 resulted in a significant increase in FoxP3⁺ cells that was blocked by a TGF-β receptor I inhibitor. We also show here that PSG1 can increase the availability of active TGF-β in vivo. As the role of CD4⁺FoxP3⁺ cells in the prevention of aGVHD is well established, we tested whether PSG1 has beneficial effects in a murine aGHVD transplantation model. PSG1-treated mice had reduced numbers of tissue-infiltrating inflammatory CD3⁺ T cells and had increased expression of FoxP3 in T cells compared with vehicle-treated mice. In addition, administration of PSG1 significantly inhibited aGVHD-associated weight loss and mortality. On the other hand, administration of PSG1 was less effective in managing aGVHD in the presence of an alloimmune reaction against a malignancy in a graft-versus-leukemia experimental model. Combined, this data strongly suggests that PSG1 could be a promising treatment option for patients with aGVHD following bone marrow transplantation for a nonmalignant condition, such as an autoimmune disorder or a genetic immunodeficiency.     

Suppression of Coronary Vasculitis in a Murine Model of Kawasaki Disease Using an Angiogenesis Inhibitor

Coronary arteritis can be induced in C57BL/6 mice with a single intraperitoneal (ip) injection ofLactobacillus caseicell fragments. Histologic sections resemble the vasculitis and aneurysms observed in the medium-sized coronary arteries of children with Kawasaki disease. Since endothelial cells could play an important role in the development of vasculitis, a recently described angiogenesis inhibitor that is not an immunosuppressive agent, AGM-1470 (derived fromAspergillus fumigatus), was used to evaluate its therapeutic potential in this model. A total of 32 mice were administered 0.5 mg of sterileL. caseipreparation ip on day 0 and randomized to either a treatment (AGM-1470, 27mg/kg sc alternate days) or a control (vehicle only) protocol. Hearts were harvested on day 14 (early disease) or at the end of the study on day 28 (established disease). Histologic sections were scored blindly for vasculitis. Day 14 sections from both protocols manifested only minimal disease, indicating that the vasculitis had not yet matured. By day 28, the AGM-1470 group had significantly less coronary vasculitis than the control group (0.7 vs 2.6,p< 0.005, respectively). These studies suggest that endothelial cells may play an active role in this pathologic process and that angiogenesis inhibitors, such as AGM-1470, could be useful tools for the treatment and understanding of vasculitis.     

The Chronic Gastrointestinal Manifestations of Chagas Disease

Chagas disease is an infectious disease caused by the protozoan Trypanosoma cruzi. The disease mainly affects the nervous system, digestive system and heart. The objective of this review is to revise the literature and summarize the main chronic gastrointestinal manifestations of Chagas disease. The chronic gastrointestinal manifestations of Chagas disease are mainly a result of enteric nervous system impairment caused by T. cruzi infection. The anatomical locations most commonly described to be affected by Chagas disease are salivary glands, esophagus, lower esophageal sphincter, stomach, small intestine, colon, gallbladder and biliary tree. Chagas disease has also been studied in association with Helicobacter pylori infection, interstitial cells of Cajal and the incidence of gastrointestinal cancer.     

Bone Marrow Transplantation after Nonmyeloablative Treosulfan Conditioning Is Curative in a Murine Model of Sickle Cell Disease

Allogeneic hematopoietic stem cell transplantation (HSCT) can be curative for patients with sickle cell disease (SCD). However, morbidity associated with myeloablative conditioning and graft-versus-host disease has limited its utility. To this end, autologous HSCT for SCD using lentiviral gene-modified bone marrow (BM) or peripheral blood stem cells has been undertaken, although toxicities of fully ablative conditioning with busulfan and incomplete engraftment have been encountered. Treosulfan, a busulfan analog with a low extramedullary toxicity profile, has been used successfully as part of a myeloablative conditioning regimen in the allogeneic setting in SCD. To further minimize toxicity of conditioning, noncytotoxic monoclonal antibodies that clear stem cells from the marrow niche, such as anti-c-Kit (ACK2), have been considered. Using a murine model of SCD, we sought to determine whether nonmyeloablative conditioning followed by transplantation with syngeneic BM cells could ameliorate the disease phenotype. Treosulfan and ACK2, in a dose-dependent manner, decreased BM cellularity and induced cytopenia in SCD mice. Conditioning with treosulfan alone at nonmyeloablative dosing (3.6?g/kg), followed by transplantation with syngeneic BM donor cells, permitted long-term mixed-donor chimerism. Level of chimerism correlated with improvement in hematologic parameters, normalization of urine osmolality, and improvement in liver and spleen pathology. Addition of ACK2 to treosulfan conditioning did not enhance engraftment. Our data suggests that pretransplant conditioning with treosulfan alone may allow sufficient erythroid engraftment to reverse manifestations of SCD, with clinical application as a preparative regimen in SCD patients undergoing gene-modified autologous HSCT.     

Oxidative Alterations in Alzheimer's Disease

There is increasing evidence that free radical damage to brain lipids, carbohydrates, proteins, and DNA is involved in neuron death in neurodegenerative disorders. The largest number of studies have been performed in Alzheimer's disease (AD) where there is considerable support for the oxidative stress hypothesis in the pathogenesis of neuron degeneration. In autopsied brain there is an increase in lipid peroxidation, a decline in polyunsaturated fatty acids (PUFA) and an increase in 4-hydroxynonenal (HNE), a neurotoxic aldehyde product of PUFA oxidation. Increased protein oxidation and a marked decline in oxidative-sensitive enzymes, glutamine synthetase and creatinine kinase, are found in the brain in AD. Increased DNA oxidation, especially 8-hydroxy-2'-deoxyguanosine (8-OHdG) is present in the brain in AD. Immunohistochemical studies show the presence of oxidative stress products in neurofibrillary tangles and senile plaques in AD. Markers of lipid peroxidation (HNE, isoprostanes) and DNA (8-OHdG) are increased in CSF in AD. In addition, inflammatory response markers (the complement cascade, cytokines, acute phase reactants and proteases) are present in the brain in AD. These findings, coupled with epidemiologic studies showing that anti-inflammatory agents slow the progression or delay the onset of AD, suggest that inflammation plays a role in AD. Overall these studies indicate that oxidative stress and the inflammatory cascade, working in concert, are important in the pathogenetic cascade of neurodegeneration in AD, suggesting that therapeutic efforts aimed at both of these mechanisms may be beneficial.     

Heritability of Phenotypes Associated with Glucose Homeostasis and Adiposity in a Rural Area of Brazil

We aimed to estimate the heritability and genetic correlation between glucose homeostasis and adiposity traits in a population in a rural community in Brazil. The Jequitinhonha Community Family Study cohort consists of subjects aged ≥18 years residing in rural areas in Brazil. The data on the following traits were assembled for 280 individuals (51.7% women): body mass index (BMI), body fat percentage, waist and mid‐upper arm circumferences, triceps skinfold, conicity index, insulin, glucose, high‐density lipoprotein cholesterol (HDLc), triglycerides and C‐reactive protein. Extended pedigrees were constructed up to the third generation of individuals using the data management software PEDSYS. The heritability and genetic correlations were estimated using a variance component method. The age‐ and sex‐adjusted heritability values estimated for insulin (h² = 52%), glucose (h² = 51%), HDLc (h² = 58%), and waist circumference (WC; h² = 49%) were high. Significantly adjusted genetic correlations were observed between insulin paired with each of the following phenotypes; (BMI; ρg = 0.48), WC (ρg = 0.47) and HDLc (ρg = ?0.47). The homeostasis model assessment of insulin resistance (HOMA‐IR) was genetically correlated with BMI (ρg = 0.53) and HDLc (ρg = ?0.58). The adjusted genetic correlations between traits were consistently higher compared with the environmental correlations. In conclusion, glucose metabolism and adiposity traits are highly heritable and share common genetic effects with body adiposity traits.     

Endothelial Dysfunction and Altered Mechanical and Structural Properties of Resistance Arteries in a Murine Model of Graft-versus-Host Disease

A putative involvement of the vasculature seems to play a critical role in the pathophysiology of graft-versus-host disease (GVHD). We aimed to characterize alterations of mesenteric resistance arteries in GVHD in a fully MHC-mismatched model of BALB/c mice conditioned with total body irradiation that underwent transplantation with bone marrow cells and splenocytes from syngeneic (BALB/c) or allogeneic (C57BL/6) donors. After 4 weeks, animals were sacrificed and mesenteric resistance arteries were studied in a pressurized myograph. The expression of endothelial (eNOS) and inducible nitric oxide (NO)–synthase (iNOS) was quantified and vessel wall ultrastructure was investigated with electron microscopy. The myograph study revealed an endothelial dysfunction in allogeneic-transplant recipients, whereas endothelium-independent vasodilation was similar to syngeneic-transplant recipients or untreated controls. The expression of eNOS was decreased and iNOS increased, possibly contributing to endothelial dysfunction. Additionally, arteries of allogeneic transplant recipients exhibited a geometry-independent increase in vessels strain. For both findings, electron microscopy provided a structural correlate by showing severe damage of the whole vessel wall in allogeneic-transplant recipient animals. Our study provides further data to prove, and is the first to characterize, functional and structural vascular alterations in the early course after allogeneic transplantation directly in an ex vivo setting and, therefore, strongly supports the hypothesis of a vascular form of GVHD.     

Graft-versus-Host Disease Causes Broad Suppression of Hematopoietic Primitive Cells and Blocks Megakaryocyte Differentiation in a Murine Model

Cytopenia and delayed immune reconstitution with acute graft-versus-host disease (aGVHD) indicate a poor prognosis. However, how donor-derived cell hematopoiesis is impaired in aGVHD is not well understood. We addressed this issue by studying the kinetics of hematopoiesis and the functions of hematopoietic stem and progenitor cells in an aGVHD model with haplo-MHC–matched murine bone marrow transplantation. Although hematopoiesis was progressively suppressed during aGVHD, the hematopoietic regenerative potential of donor-derived hematopoietic stem cells remains intact. There was a dramatic reduction in primitive hematopoietic cells and a defect in the ability of these cells to generate common myeloid progenitors (CMPs) and megakaryocyte/erythrocyte progenitors (MEPs). These effects were observed along with a concomitant increase in granulocyte/macrophage progenitors, suggesting that differentiation into MEPs is blocked during aGVHD. Interestingly, cyclosporine A was able to partially reverse the hematopoietic suppression as well as the differentiation blockage of CMPs. These data provide new insights into the pathogenesis of aGVHD and may improve the clinical management of aGVHD.     

Recombinant ESAT-6-Like Proteins Provoke Protective Immune Responses against Invasive Staphylococcus aureus Disease in a Murine Model

Staphylococcus aureus is a common pathogen found in the community and in hospitals. Most notably, methicillin-resistant S. aureus is resistant to many antibiotics, which is a growing public health concern. The emergence of drug-resistant strains has prompted the search for alternative treatments, such as immunotherapeutic approaches. To date, most clinical trials of vaccines or of passive immunization against S. aureus have ended in failure. In this study, we investigated two ESAT-6-like proteins secreted by S. aureus, S. aureus EsxA (SaEsxA) and SaEsxB, as possible targets for a vaccine. Mice vaccinated with these purified proteins elicited high titers of anti-SaEsxA and anti-SaEsxB antibodies, but these antibodies could not prevent S. aureus infection. On the other hand, recombinant SaEsxA (rSaEsxA) and rSaEsxB could induce Th1- and Th17-biased immune responses in mice. Mice immunized with rSaEsxA and rSaEsxB had significantly improved survival rates when challenged with S. aureus compared with the controls. These findings indicate that SaEsxA and SaEsxB are two promising Th1 and Th17 candidate antigens which could be developed into multivalent and serotype-independent vaccines against S. aureus infection.     

Innate and Acquired Immunity in the Pathogenesis of Chagas Disease

The apparent discrepancy between the intensity of inflammatory reaction and scarce number of parasites in chronic chagasic myocarditis prompt several investigators to hypothesize that an autoimmune process was involved in the pathogenesis of Chagas disease. Here, we recapitulate diverse molecular and cellular mechanisms of innate and acquired immunity involved in the control of parasite replication and in the build up of myocarditis observed during infection with Trypanosoma cruzi. In addition, we review the immunoregulatory mechanisms responsible for preventing excessive immune response elicited by this protozoan parasite. Ongoing studies in this research area may provide novel therapeutic strategies that could enhance the immunoprotective response while preventing the deleterious parasite-elicited responses observed during Chagas disease.     

褪黑素对系统性红斑狼疮样小鼠的影响

为了观察褪黑素 (MT )对CJ S13 1所致的SLE样小鼠改变的影响并探讨其作用机制。采用空肠弯曲菌CJ S13 1和CFA混合免疫动物 ,诱导SLE样小鼠改变。结果表明MT 0 0 1、 0 10、 1 0mg/kg/d× 2 8d ,ig能部分或完全拮抗血清抗ssDNA和组蛋白IgG型自身抗体水平的升高 ,抑制ConA及LPS诱导的淋巴细胞增殖反应的增强 ,降低动物尿蛋白水平 ,减轻肾组织病变程度。提示一定剂量的MT对SLE样小鼠改变具有一定的保护作用。     

MyD88-Deficient Mice Exhibit Decreased Parasite-Induced Immune Responses but Reduced Disease Severity in a Murine Model of Neurocysticercosis

The symptomatic phase of neurocysticercosis (NCC), a parasitic disease of the central nervous system (CNS) in humans, is characterized by inflammatory responses leading to neuropathology and, in some cases, death. In an animal model of NCC in which mice were intracranially inoculated with the parasite Mesocestoides corti, the infection in mice lacking the myeloid differentiation primary response gene 88 (MyD88^−/−) resulted in decreased disease severity and improved survival compared with that in wild-type (WT) mice. The CNS of MyD88^−/− mice was more quiescent, with decreased microgliosis and tissue damage. These mice exhibited substantially reduced primary and secondary microglial nodule formations and lacked severe astrogliotic reactions, which were seen in WT mice. Significantly reduced numbers of CD11b⁺ myeloid cells, αβ T cells, γδ T cells, and B cells were present in the brains of MyD88^−/− mice in comparison with those of WT mice. This decrease in cellular infiltration correlated with a decrease in blood-brain barrier permeability, as measured by reduced fibrinogen extravasation. Comparisons of cytokine expression indicated a significant decrease in the CNS levels of several inflammatory mediators, such as tumor necrosis factor alpha, gamma interferon, CCL2, and interleukin-6, during the course of infection in MyD88^−/− mice. Collectively, these findings suggest that MyD88 plays a prominent role in the development of the hyperinflammatory response, which in turn contributes to neuropathology and disease severity in NCC.Neurocysticercosis (NCC) is the most common parasitic disease of the central nervous system (CNS), occurring as a result of infection of the brain with the larval stage of the tape worm parasite Taenia solium (56). In humans, the disease has a long asymptomatic phase, typically 3 to 5 years, followed by the symptomatic phase, consisting of clinical signs such as epilepsy (43), increased intracranial (i.c.) pressure, obstructive hydroencephalus, stroke, and encephalitis (55, 56). More than 25% of all epileptic cases diagnosed in adults worldwide are due to NCC (19). The sequential progression from asymptomatic to symptomatic NCC depends upon the degeneration of larvae, caused by either therapeutic treatment or normal attrition. This leads to the induction of a strong inflammatory response, causing a chronic granulomatous reaction and the manifestation of symptoms of the disease (41, 57). The immune response in the CNS of symptomatic patients consists of an overt TH1 phenotype (39) or a mixed TH1, TH2, and TH3 phenotype, depending upon the absence or presence of granuloma formation (38). Specifically, the TH1 hyperinflammatory response prevailing in the CNS during the symptomatic phase is thought to be responsible for the severe neuropathology and mortality associated with NCC (55). Direct evidence that the inflammatory/TH1 response contributes to the neuropathology and severity of NCC, however, is limited. Nevertheless, along with antiparasitic drugs, the treatment of NCC patients with immunosuppressive/anti-inflammatory factors such as corticosteroids helps to control the host inflammatory response and associated neuropathology (32). Long-term treatments with steroids, however, lead to problematic side effects that may become life-threatening. Therefore, despite recent advances made in detection and therapy, effective treatment of NCC remains a major challenge, as cysticidal treatment itself results in the symptoms that one is trying to control and/or the manifestation of other complications. Therefore, it is important to understand the pathophysiological basis of the CNS inflammatory response in NCC and to identify critical molecules responsible for such responses.The myeloid differentiation primary response gene 88 (MyD88) is an important regulator of the host inflammatory response (50, 51). The protein produced by the MyD88 gene is an adaptor molecule necessary for signal transductions originating from the interleukin-1 receptor (IL-1R)/IL-18R family of receptors and the Toll-like receptor (TLR) family of proteins (35). Once engaged, TLRs signal through a common pathway involving MyD88 (42), leading to the subsequent downstream activation of the NF-κB and mitogen-activated protein (MAP) kinase pathways and inducing a TH1 proinflammatory response (28). Previous studies have demonstrated that MyD88 knockout mice exhibit defective proinflammatory responses and display dramatic defects in antimicrobial immunity in a variety of infectious disease models, highlighting the importance of this molecule in influencing a wide array of host responses and disease control (2, 8, 18, 45, 52). A contrasting situation occurs in onchocerciasis, an infection of the eye caused by another helminth parasite, Onchocerca volvulus. In this case, MyD88 plays a pivotal role in the development of a persistent hyperinflammatory response eventuating in corneal haze and hence contributing to the development of river blindness (22, 26). An important unanswered question, therefore, is whether MyD88-dependent mechanisms are involved in inflammatory responses that contribute to the observed pathology and severity of NCC or play an essential role in the containment of this disease.The goal of this study was to identify the overall effect of the absence of the MyD88-dependent signaling pathway, using a well-characterized murine model of NCC developed in our laboratory (14). In the present study, we compared the susceptibilities and immunopathology of MyD88^−/− and wild-type (WT) mice infected i.c. with Mesocestoides corti. The contribution of MyD88 signaling to CNS inflammation was assessed by measuring infiltration of various immune cells into the brain, blood-brain barrier (BBB) permeability, and proinflammatory cytokine responses in the CNS of MyD88^−/− and WT mice.     

Environmental Modulation of Oral Treponeme Virulence in a Murine Model

This investigation examined the effects of environmental alteration on the virulence of the oral treponemes Treponema denticola and Treponema pectinovorum. The environmental effects were assessed by using a model of localized inflammatory abscesses in mice. In vitro growth of T. denticola and T. pectinovorum as a function of modification of the cysteine concentration significantly enhanced abscess formation and size. In contrast, growth of T. denticola or T. pectinovorum under iron-limiting conditions (e.g., dipyridyl chelation) had no effect on abscess induction in comparison to that when the strains were grown under normal iron conditions. In vivo modulation of the microenvironment at the focus of infection with Cytodex beads demonstrated that increasing the local inflammation had no effect on lesion induction or size. In vivo studies involved the determination of the effects of increased systemic iron availability (e.g., iron dextran or phenylhydrazine) on the induction, kinetics, and size of lesions. T. denticola induced significantly larger lesions in mice with iron pretreatment and demonstrated systemic manifestations of the infectious challenge and an accompanying spreading lesion with phenylhydrazine pretreatment (e.g., increases in circulating free hemoglobin). In contrast, T. pectinovorum virulence was minimally affected by this in vivo treatment to increase iron availability. T. denticola virulence, as evaluated by lesion size, was increased additively by in vivo iron availability, and cysteine modified growth of the microorganism. Additionally, galactosamine sensitized mice to a lethal outcome following infection with both T. denticola and T. pectinovorum, suggesting an endotoxin-like activity in these treponemes. These findings demonstrated the ability to modify the virulence capacity of T. denticola and T. pectinovorum by environmental conditions which can be evaluated by using in vivo murine models.