Franca Ferraraccio

Divergence of gut permeability and mucosal immune gene expression in two gluten-associated conditions: celiac disease and gluten sensitivity

BackgroundCeliac disease (CD) is an autoimmune enteropathy triggered by the ingestion of gluten. Gluten-sensitive individuals (GS) cannot tolerate gluten and may develop gastrointestinal symptoms similar to those in CD, but the overall clinical picture is generally less severe and is not accompanied by the concurrence of tissue transglutaminase autoantibodies or autoimmune comorbidities. By studying and comparing mucosal expression of genes associated with intestinal barrier function, as well as innate and adaptive immunity in CD compared with GS, we sought to better understand the similarities and differences between these two gluten-associated disorders.MethodsCD, GS and healthy, gluten-tolerant individuals were enrolled in this study. Intestinal permeability was evaluated using a lactulose and mannitol probe, and mucosal biopsy specimens were collected to study the expression of genes involved in barrier function and immunity.ResultsUnlike CD, GS is not associated with increased intestinal permeability. In fact, this was significantly reduced in GS compared with controls (P = 0.0308), paralleled by significantly increased expression of claudin (CLDN) 4 (P = 0.0286). Relative to controls, adaptive immunity markers interleukin (IL)-6 (P = 0.0124) and IL-21 (P = 0.0572) were expressed at higher levels in CD but not in GS, while expression of the innate immunity marker Toll-like receptor (TLR) 2 was increased in GS but not in CD (P = 0.0295). Finally, expression of the T-regulatory cell marker FOXP3 was significantly reduced in GS relative to controls (P = 0.0325) and CD patients (P = 0.0293).ConclusionsThis study shows that the two gluten-associated disorders, CD and GS, are different clinical entities, and it contributes to the characterization of GS as a condition associated with prevalent gluten-induced activation of innate, rather than adaptive, immune responses in the absence of detectable changes in mucosal barrier function.

Myocardial lipid accumulation in patients with pressure-overloaded heart and metabolic syndrome

We evaluated the role of sterol-regulatory element binding protein (SREBP)-1c/peroxisome proliferator activated receptor-&ggr; (PPAR&ggr;) pathway on heart lipotoxicity in patients with metabolic syndrome (MS) and aortic stenosis (AS). Echocardiographic parameters of heart function and structural alterations of LV specimens were studied in patients with (n = 56) and without (n = 61) MS undergoing aortic valve replacement. Tissues were stained with hematoxylin-eosin (H and E) and oil red O for evidence of intramyocyte lipid accumulation. The specimens were also analyzed with PCR, Western blot, and immunohistochemical analysis for SREBP-1c and PPAR&ggr;. Ejection fraction (EF) was lower in MS compared with patients without MS (P < 0.001); no difference was found in aortic orifice surface among the groups. H and E and oil red O staining of specimens from MS patients revealed several myocytes with intracellular accumulation of lipid, whereas these alterations were not detected in biopsies from patients without MS. Patients without MS have low levels and weak immunostaining of SREBP-1c and PPAR&ggr; in heart specimens. In contrast, strong immunostaining and higher levels of SREBP-1c and PPAR&ggr; were seen in biopsies from the MS patients. Moreover, we evidenced a significative correlation between both SREBP-1c and PPAR&ggr; and EF and intramyocyte lipid accumulation (P < 0.001). SREBP-1c may contribute to heart dysfunction by promoting lipid accumulation within myocytes in MS patients with AS; SREBP-1c may do it by increasing the levels of PPAR&ggr; protein.

Long-term inhibition of dipeptidyl peptidase-4 in Alzheimer’s prone mice

We tested here the impact of a long-term inhibition of dipeptidyl peptidase-4 (DPP-4) with sitagliptin on the deposition of amyloid-beta within the brain and deficits in memory-related behavioral paradigms in a model of Alzheimers disease (AD): double transgenic mice B6*Cg-Tg(APPswe,PSEN1dE9)85Dbo/J. Mice began to receive sitagliptin at 7 months of age. Three different dose of sitagliptin (5, 10 and 20 mg/kg), were administered daily for 12 weeks by gastric gavage. The treatments counteracted: (i) the memory impairment in the contextual fear conditioning test; (ii) increased the brain levels of GLP-1; (iii) produced significant reductions of nitrosative stress and inflammation hallmarks within the brain, as well as (iv) a significant diminution in the ultimate number and total area of betaAPP and Abeta deposits. All these effects much more evident for the dose of 20 mg/kg sitagliptin. The long-term inhibition of the endogenous DPP-4 enzymes with sitagliptin can significantly delay some forms of AD pathology, including amyloid deposition, when administered early in the disease course of a transgenic mouse model of AD.

Tight Glycemic Control Reduces Heart Inflammation and Remodeling During Acute Myocardial Infarction in Hyperglycemic Patients

OBJECTIVES We analyzed the molecular mechanisms evoked by tight glycemic control during post-infarction remodeling in human hearts. BACKGROUND The molecular mechanisms by which tight glycemic control improves heart remodeling during acute myocardial infarction (AMI) are still largely unknown. METHODS Eighty-eight patients with first AMI undergoing coronary bypass surgery were studied: 38 normoglycemic patients served as the control group; hyperglycemic patients (glucose >or=140 mg/dl) were randomized to intensive glycemic control (IGC) (n = 25; glucose 80 to 140 mg/dl) or conventional glycemic control (CGC) (n = 25; glucose 180 to 200 mg/dl) for almost 3 days before surgery, with insulin infusion followed by subcutaneous insulin treatment. Echocardiographic parameters were investigated at admission and after treatment period. During surgery, oxidative stress (nitrotyrosine, superoxide anion [O(2)(-)] production, inducible nitric oxide synthase [iNOS]), inflammation (nuclear factor kappa B [NFkappaB], tumor necrosis factor [TNF]-alpha, and apoptosis (caspase-3) were analyzed in biopsy specimens taken from the peri-infarcted area. RESULTS Compared with normoglycemic patients, hyperglycemic patients had higher myocardial performance index (MPI) (p < 0.05), reduced ejection fraction (p < 0.05), more nitrotyrosine, iNOS, and O(2)(-) production, more macrophages, T-lymphocytes, and HLA-DR (Dako, Milan, Italy) cells, and more NFkappaB-activity, TNF-alpha, and caspase-3 levels (p < 0.01) in peri-infarcted specimens. After the treatment period, plasma glucose reduction was greater in the IGC than in the CGC group (p < 0.001). Compared with IGC patients, CGC patients had higher MPI (p < 0.02), had lower ejection fraction (p < 0.05), and had more markers of oxidative stress, more inflammation and apoptosis (p < 0.01) in peri-infarcted specimens. CONCLUSIONS Tight glycemic control, by reducing oxidative stress and inflammation, might reduce apoptosis in peri-infarcted areas and remodeling in AMI patients.

Morning Blood Pressure Surge as a Destabilizing Factor of Atherosclerotic Plaque Role of Ubiquitin–Proteasome Activity

Whether morning blood pressure surge influences the molecular mechanisms of plaque progression toward instability is not known. Recently, we have demonstrated enhanced activity of the ubiquitin–proteasome system in human plaques and evidenced that it is associated with inflammatory-induced plaque rupture. We evaluated the inflammatory infiltration and ubiquitin–proteasome activity in asymptomatic carotid plaques of hypertensive patients with different patterns of morning blood pressure surge. Plaques were obtained from 32 hypertensive patients without morning blood pressure surge and 28 with morning blood pressure surge enlisted to undergo carotid endarterectomy for extracranial high-grade (>70%) internal carotid artery stenosis. Plaques were analyzed for macrophages, T-lymphocytes, human leukocyte antigen–DR+cells, ubiquitin–proteasome activity, nuclear factor-&kgr;B, inhibitor kB-&bgr;, tumor necrosis factor-&agr;, nitrotyrosine, matrix metalloproteinase-9, and collagen content (immunohistochemistry and ELISA). Compared with plaques obtained from hypertensive patients without morning blood pressure surge, plaques from with morning blood pressure surge had more macrophages, T-lymphocytes, human leukocyte antigen–DR+cells (P<0.001), ubiquitin-proteasome activity, tumor necrosis factor-&agr;, nuclear factor-kB (P<0.001), nitrotyrosine, and matrix metalloproteinase-9 (P<0.01), along with a lesser collagen content and IkB-&bgr; levels (P<0.001). Enhanced ubiquitin–proteasome activity in atherosclerotic lesions of patients with morning blood pressure surge is associated with inflammatory-dependent unstable plaque phenotype. These data suggest a potential interplay between morning blood pressure surge and ubiquitin–proteasome activity in atherosclerosis pathophysiology.

Sirtuin 6 Expression and Inflammatory Activity in Diabetic Atherosclerotic Plaques: Effects of Incretin Treatment

The role of sirtuin 6 (SIRT6) in atherosclerotic progression of diabetic patients is unknown. We evaluated SIRT6 expression and the effect of incretin-based therapies in carotid plaques of asymptomatic diabetic and nondiabetic patients. Plaques were obtained from 52 type 2 diabetic and 30 nondiabetic patients undergoing carotid endarterectomy. Twenty-two diabetic patients were treated with drugs that work on the incretin system, GLP-1 receptor agonists, and dipeptidyl peptidase-4 inhibitors for 26 ± 8 months before undergoing the endarterectomy. Compared with nondiabetic plaques, diabetic plaques had more inflammation and oxidative stress, along with a lesser SIRT6 expression and collagen content. Compared with non-GLP-1 therapy–treated plaques, GLP-1 therapy–treated plaques presented greater SIRT6 expression and collagen content, and less inflammation and oxidative stress, indicating a more stable plaque phenotype. These results were supported by in vitro observations on endothelial progenitor cells (EPCs) and endothelial cells (ECs). Indeed, both EPCs and ECs treated with high glucose (25 mmol/L) in the presence of GLP-1 (100 nmol/L liraglutide) presented a greater SIRT6 and lower nuclear factor-κB expression compared with cells treated only with high glucose. These findings establish the involvement of SIRT6 in the inflammatory pathways of diabetic atherosclerotic lesions and suggest its possible positive modulation by incretin, the effect of which is associated with morphological and compositional characteristics of a potential stable plaque phenotype.

The ubiquitin-proteasome system contributes to the inflammatory injury in ischemic diabetic myocardium: the role of glycemic control.

BACKGROUND Because the ubiquitin-proteasome pathway (UPS) is required for activation of nuclear factor kappa beta (NFkB), a transcription factor that regulates inflammatory genes, we evaluated the UPS activity, NFkB activation, and tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, in ischemic specimens of diabetic myocardium and relate them to the glycemic control (HbA(1c)), oxidative stress (nitrotyrosine, a modified amino acid produced by reactive O(2)), and cardiac outcome (echocardiographic parameters). Moreover, the role of UPS, NFkB, and TNF-alpha in the cardiac tissue injury of acute ischemia/reperfusion (I/R) was evaluated in streptozotocin (STZ)-hyperglycemic rats. Finally, this study aimed to elucidate whether an intervention on UPS with bortezomib, an inhibitor of UPS, may counteract the extensive myocardial infarction and increased inflammatory reaction into the hyperglycemic myocardium. METHODS Ventricular biopsy specimens from 16 nondiabetic and 18 type 2 diabetic patients presenting with unstable angina who underwent coronary artery bypass were collected during coronary bypass surgery. Ejection fraction (EF); myocardial performance index (MPI), which measures both systolic and diastolic function, immunostaining, and cardiac levels of nitrotyrosine; UPS activity; NFkB; and TNF-alpha were investigated in both ischemic human myocardium and heart tissue from STZ-hyperglycemic rats subject to a myocardial ischemia/reperfusion procedure. RESULTS We found that diabetic patients had higher MPI (P<.041) and reduced EF (P<.008) compared with nondiabetic patients. Diabetic specimens had higher nitrotyrosine, UPS activity, NFkB, and TNF-alpha levels compared with nondiabetic patients (P<.001). This was mirrored by consistently high levels of UPS and inflammatory markers in STZ-infarcted hearts, associated with high myocardial damage. In contrast, lesions from normoglycemic animals as well as from hyperglycemic rats treated with bortezomib showed low levels of ubiquitin-proteasome activity, inflammation, and myocardial damage (P<.01). CONCLUSIONS By contributing to the increased inflammation, the UPS overactivity may enhance the risk of complication during myocardial ischemia in diabetic patients.

Dipeptidyl Peptidase 4 Inhibition May Facilitate Healing of Chronic Foot Ulcers in Patients with Type 2 Diabetes

The pathophysiology of chronic diabetic ulcers is complex and still incompletely understood, both micro- and macroangiopathy strongly contribute to the development and delayed healing of diabetic wounds, through an impaired tissue feeding and response to ischemia. With adequate treatment, some ulcers may last only weeks; however, many ulcers are difficult to treat and may last months, in certain cases years; 19–35% of ulcers are reported as nonhealing. As no efficient therapy is available, it is a high priority to develop new strategies for treatment of this devastating complication. Because experimental and pathological studies suggest that incretin hormone glucagon-like peptide-1 may improves VEGF generation and promote the upregulation of HIF-1α through a reduction of oxidative stress, the study evaluated the effect of the augmentation of GLP-1, by inhibitors of the dipeptidyl peptidase-4, such as vildagliptin, on angiogenesis process and wound healing in diabetic chronic ulcers. Although elucidation of the pathophysiologic importance of these aspects awaits further confirmations, the present study evidences an additional aspect of how DPP-4 inhibition might contribute to improved ulcer outcome.

Morphology changes in human lung epithelial cells after exposure to diesel exhaust micron sub particles (PM1.0) and pollen allergens

In the recent literature there has been an increased interest in the effects of particulate matter on the respiratory tract. The objective of this study was to use an in vitro model of type II lung epithelium (A549) to evaluate the cell ability to take up sub-micron PM(1.0) particles (PM(1.0)), Parietaria officinalis (ALL), and PM(1.0) + ALL together. Morphological analysis performed by Transmission Electron Microscope (TEM) showed that PM and ALL interacted with the cell surface, then penetrating into the cytoplasm. Each single treatment was able to point out a specific change in the morphology. The cells treated appear healthy and not apoptotic. The main effect was the increase of: multilamellar bodies, lysosomal enzymes, microvilli, and presence of vesicle/vacuoles containing particles. These observations demonstrate morphological and functional alterations related to the PM(1.0) and P. officinalis and confirm the induction of the inflammatory response in lung cells exposed to the inhalable particles.

Involvement of subtype 1 metabotropic glutamate receptors in apoptosis and caspase-7 over-expression in spinal cord of neuropathic rats

The effect of the non-selective, 1-aminoindan-1,5-dicarboxylic acid (AIDA), and selective (3,4-dihydro-2H-pyrano[2,3-b]quinolin-7-yl)-(cis-4-methoxycyclohexyl) methanone (JNJ16259685), metabotropic glutamate subtype 1 (mGlu1) receptor antagonists, on rat sciatic nerve chronic constrictive injury (CCI)-induced hyperalgesia, allodynia, spinal dorsal horn apoptosis, and gliosis was examined at 3 and 7 days post-injury. RT-PCR analysis showed increased expression of bax, apoptotic protease-activating factor-1 (apaf-1), nestin, GFAP, and caspase-7 mRNA in the dorsal horn spinal cord by 3 days post-CCI. At 7 days post-CCI, only over-expression of bcl-2, nestin and GFAP mRNA was observed. Administration of AIDA reduced thermal hyperalgesia and mechanical allodynia at 3 and 7 days post-CCI; administration of JNJ16259685 reduced thermal hyperalgesia at 3 and 7 days post-CCI, but not mechanical allodynia. AIDA decreased the mRNA levels of bax, apaf-1, GFAP and caspase-7 genes. JNJ16259685 increased the mRNA levels of bcl-2 and GFAP gene, and decreased APAF-1 and caspases-7 genes. Inhibiting mGlu1 receptors also reduced TUNEL-positive profiles and immunohistochemical reactivity for caspase-7. We report here that despite inhibiting CCI-induced over-expression of pro-apoptotic genes in the spinal cord dorsal horn, the selective mGlu1 receptor antagonist JNJ16259685 exerted only a slight and transient allodynic effect. Moreover, JNJ16259685, but not the non-selective AIDA, increased astrogliosis which may account for its decreased analgesic efficacy. This study provides evidence that the contemporary and partial blockade of group I and likely ionotropic glutamate receptors may be a more suitable therapy than selective blockade of mGlu1 subtype receptors condition to decrease neuropathic pain symptoms.