Necrotizing enterocolitis (NEC) triggers an intense inflammatory response in the neonatal gut associated with cytokine activation, altered nutrient status and intracellular O2-deprivation. Endothelial cell adhesion molecules (ECAMs) play critical roles in driving immune cell infiltration into inflamed gut. Currently, relationships between inflammation, metabolism and ECAM expression remain poorly understood in NEC. We studied the effects of metabolic depletion (aglycemia/ hypoxia) on TNF-α  mediated ECAM expression including ICAM-1, MAdCAM-1, VCAM-1 and E-selectin, in vitro in intestinal microvascular endothelial cells (IMEC).
To study the effects of TNF-α, aglycemia and hypoxia (alone or in combination) IMECs expression of adhesion molecules was studied using cell surface ELISA and immunoblotting.
Total VCAM-1 expression was induced TNF-α and by hypoxia + TNF-α, cell surface expression was induced by hypoxia, TNF-α, TNF- α+hypoxia, and TNF- α+hypoxia and aglycemia. Total ICAM-1 increased following TNF- α, TNF- α+hypoxia, hypoxia + aglycemia, and TNF- α+hypoxia + aglycemia. Total MAdCAM-1 protein expression was significantly induced by a combination of TNF-α+hypoxia + aglycemia and cell surface expression induced by TNF- α+hypoxia. Surface expression of E-selectin was induced by TNF- α+aglycemia and TNF- α+hypoxia + aglycemia.
Energy metabolism influences inflammation induced injury through mobilization of intestinal ECAMs, and may represent an important mechanism in NEC pathology.
Copyright © 2019 Elsevier B.V. All rights reserved.

Immune rejection continues to threaten all tissue transplants. Here we sought to determine whether platelet (P)- and endothelial (E)-selectin mediate T cell recruitment in corneal transplantation and whether their blockade can reduce T cell graft infiltration and improve long-term corneal allograft survival.In a murine model of allogeneic corneal transplantation, we used PCR and immunohistochemistry to investigate expression of P- and E-selectin in rejected versus accepted allografts and lymph node flow cytometry to assess expression of selectin ligands by effector T cells. Using P- and E-selectin neutralizing antibodies, we evaluated the effect of blockade on CD4 T cell recruitment, as well as the effect of anti-E-selectin on long-term allograft survival.The P- (93.3-fold, P < 0.05) and E-selectin (17.1-fold, P < 0.005) are upregulated in rejected versus accepted allogeneic transplants. Type 1 T helper cells from hosts with accepted and rejected grafts express high levels of P-selectin glycoprotein ligand 1 and glycosylated CD43. In vivo blockade of P (0.47 ± 0.03, P < 0.05) and E selectin (0.49 ± 0.1, P < 0.05) reduced the number of recruited T cells compared with IgG control (0.98 ± 0.1). Anti-E-selectin reduced the number of mature antigen-presenting cells trafficking to lymphoid tissue compared with control (6.96 ± 0.9 vs 12.67 ± 0.5, P < 0.05). Anti-E-selectin treatment delayed graft rejection and increased survival compared with control, although this difference did not reach statistical significance.In a model of corneal transplantation, P- and E-selectin mediate T cell recruitment to the graft, E-selectin mediates APC trafficking to lymphoid tissue, and blockade of E-selectin has a modest effect on improving long-term graft survival.

Neurovascular and gliovascular interactions significantly affect endothelial phenotype. Physiologically, brain endothelium attains several of its properties by its intimate association with neurons and astrocytes. However, during cerebrovascular pathologies such as cerebral ischemia, the uncoupling of neurovascular and gliovascular units can result in several phenotypical changes in brain endothelium. The role of neurovascular and gliovascular uncoupling in modulating brain endothelial properties during cerebral ischemia is not clear. Specifically, the roles of metabolic stresses involved in cerebral ischemia, including aglycemia, hypoxia and combined aglycemia and hypoxia (oxygen glucose deprivation and re-oxygenation, OGDR) in modulating neurovascular and gliovascular interactions are not known. The complex intimate interactions in neurovascular and gliovascular units are highly difficult to recapitulate in vitro. However, in the present study, we used a 3D co-culture model of brain endothelium with neurons and astrocytes in vitro reflecting an intimate neurovascular and gliovascular interactions in vivo. While the cellular signaling interactions in neurovascular and gliovascular units in vivo are much more complex than the 3D co-culture models in vitro, we were still able to observe several important phenotypical changes in brain endothelial properties by metabolically stressed neurons and astrocytes including changes in barrier, lymphocyte adhesive properties, endothelial cell adhesion molecule expression and in vitro angiogenic potential.

Obesity increases circulating cell-endothelial cell interactions; an early marker of inflammation in laboratory model of sepsis, but little is known about the effect of different adipokines. Adiponectin is an anti-inflammatory adipokine secreted by adipocytes. Adiponectin deficiency is implicated in exaggerated proinflammatory phenotype in both obesity and sepsis via increased proinflammatory cytokine expression. However the effect of adiponectin deficiency on circulating cell-endothelial cell interactions in polymicrobial sepsis is unknown. Furthermore although brain dysfunction in septic patients is a known predictor of death, the pathophysiology involved is unknown. In the current study, we examined the effects of adiponectin deficiency on leukocyte (LA) and platelet adhesion (PA) in cerebral microcirculation of septic mice. Adiponectin deficient (Adipoq(-/-): Adko) and background strain C57Bl/6 (wild type (WT)) mice were used. Sepsis was induced using cecal ligation and puncture (CLP). We studied LA and PA in the cerebral microcirculation using intravital fluorescent video microscopy (IVM), blood brain barrier (BBB) dysfunction using Evans Blue (EB) leakage method and E-selectin expression using dual radiolabeling technique in different WT and Adko mice with CLP. Adiponectin deficiency significantly exaggerated LA (WT-CLP:201 ± 17; Adko-CLP: ± 53 cells/mm(2); P < 0.05) and PA (WT-CLP:125 ± 17; Adko-CLP:188 ± 20 cells/mm(2); P < 0.05) in cerebral microcirculation, EB leakage (WT-CLP:10 ± 3.7; Adko-CLP:24 ± 4.3 ng/g × µl plasma; P < 0.05) and E-selectin expression (WT-CLP:0.06 ± 0.11; Adko-CLP:0.44 ± 0.053 ng/g; P < 0.05) in the brain tissue of the mice with CLP. Furthermore, E-selectin monoclonal antibody (mAb) treatment attenuated cell adhesion and BBB dysfunction of Adko-CLP mice. Adiponectin deficiency is associated with exaggerated leukocyte and PA in cerebral microcirculation of mice with CLP via modulation of E-selectin expression.

Cytokines contribute to cerebro-vascular inflammatory and immune responses by inducing ECAMs' expression. Ischemic insults can be separated into aglycemic and hypoxic components. However, whether aglycemia, hypoxia or OGD plays a major role in dysregulating BBB or promotes immune cell infiltration via ECAMs' expression is not clear. We investigated how expression of ICAM-1, VCAM-1, MAdCAM-1, PECAM-1, E- and P-selectin in response to TNF-α, IL-1β and IFN-γ was altered by aglycemia (A), hypoxia (H) or combined oxygen glucose deprivation (OGD).
A cell surface enzyme linked immunoabsorbent assay (cell surface ELISA) was used to analyze ECAM expression.
We observed that ICAM-1 and PECAM-1 expressions were insensitive to hypoxia, aglycemia or OGD. Conversely, VCAM-1 and E-selectin were increased by hypoxia, but not by aglycemia. MAdCAM-1 and P-selectin were induced by hypoxia, and decreased by aglycemia. Patterns of cytokine-regulated ECAMs' expression were also modified by metabolic conditions.
Our results indicate that patterns of inflammation-associated ECAMs represent cumulative influences from metabolic stressors, as well as cytokine activation. The expression of ECAMs following tissue injury reflects mechanistic interactions between metabolic disturbances, and alterations in tissue cytokines. Normalization of tissue metabolism, as well as cytokine profiles, may provide important targets for therapeutic treatment of inflammation.
© 2012 John Wiley & Sons Ltd.