Translocation of microbial products has been described in chronic human immunodeficiency virus (HIV) infection and correlates with activation of the immune system. We investigated the potential translocation of microbial products in idiopathic CD4 lymphocytopenia (ICL), a rare disorder characterized by low CD4 T cell counts in the absence of HIV infection. Plasma lipopolysaccharide (LPS) levels and T cell activation were measured in a cross-sectional cohort study of patients with ICL and HIV infection and healthy control subjects. Increases in CD4 T cell proliferation but not CD8 T cell proliferation were observed in patients with ICL. LPS levels were significantly elevated both in patients with ICL and in patients with HIV infection, and they were strongly correlated with the proportion of proliferating CD4 T cells in the cohort of patients with ICL (r = 0.88; P = .003). The proportions of T helper (Th) 17 and Th1 CD4 cells in peripheral blood were similar between patients with ICL, patients with HIV infection, and control subjects. These findings suggest a potential association of translocation of microbial products with perturbed CD4 T cell homeostasis in individuals with CD4 lymphopenic states other than HIV infection.

Objective Many vascular surgeons construct arteriovenous fistula (AVF) for hemodialysis access as the primary choice access. However, a significant number of AVF fail to mature leading to patient frustration and repeated operations. MMP activity, particularly MMP-2 and MMP-9 may be important for AVF maturation. We therefore sought to identify whether serum MMPs could serve as a biomarker for predicting future successful AVF maturation. Methods Patients with chronic renal insufficiency requiring long-term access had blood collected at the time of surgery. Serum was separated from whole blood by the use of an ultracentrifuge at 1000g for 10 minutes. Serum aliquots were then frozen at -80C until used for analysis. MMP-2, MMP-9, TIMP-2, and TIMP-4 were assayed using the ELISA technique. Patients were divided into failed and matured groups depending upon clinical endpoints. Successful maturation was considered in patients who had specific duplex findings or one month of successful two needle cannulation hemodialysis. MMP/TIMP ratios were calculated as an index of the MMP axis activity since MMP activity parallel alterations in their TIMPs. Results Twenty patients were enrolled, 13 patients had successful maturation and 7 had failure of AVF maturation. Significantly higher serum levels of MMP-2/TIMP-2 was found in patients who had AVF that matured compared to those that failed (P=.003). Similarly, a trend towards increased serum levels of MMP-9/TIMP-4 were found in patients with successful AVF (P=.06). Conclusions MMP-2 and TIMP-2 levels were different among patients who mature their fistulae versus those who did not. Further follow-up studies to determine the predictability of AVF maturation using relative patient serum levels of MMP-2 and TIMP-2 should be performed.

Matrix metalloproteinases (MMP) have been implicated in multiple stages of cancer metastasis. Tissue inhibitor of metalloproteinase-2 (TIMP-2) plays an important role in regulating MMP-2 activity. By forming a ternary complex with pro-MMP-2 and its activator MMP-14 on the cell surface, TIMP-2 can either initiate or restrain the cleavage and subsequent activation of MMP-2. Our recent work has shown that breast cancer cell adhesion to vascular endothelial cells activates endothelial MMP-2, promoting tumor cell transendothelial migration (TEME). However, the mechanism of MMP-2 regulation during TEME remains unclear. In the current study, we present evidence that MMP-14 is expressed in both invasive breast cancer cells (MDA-MB-231 and MDA-MB-436) and lung microvascular endothelial cells (HBMVEC-L), whereas TIMP-2 is exclusively expressed and released from the cancer cells. The tumor cell–derived TIMP-2 was further identified as a major determinant of endothelial MMP-2 activity during tumor cell transmigration in the presence of MMP-14. This response was associated with endothelial barrier dysfunction because coculture of MDA-MB-231 or MDA-MB-436 with HBMVEC-L caused a significant decrease in transendothelial electrical resistance concomitantly with endothelial cell-cell junction disruption and tumor cell transmigration. Knockdown of TIMP-2 or inhibition of TIMP-2/MMP-14 attenuated MMP-2–dependent transendothelial electrical resistance response and TEME. These findings suggest a novel interactive role of breast cancer cells and vascular endothelial cells in regulating the TIMP-2/MMP-14/MMP-2 pathway during tumor metastasis.

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Objective Statin therapy is utilized in the medical management of patients with peripheral vascular disease (PVD) and abdominal aortic aneurysm (AAA) for the pleiotropic and anti-inflammatory benefits. We hypothesize that the inflammatory mechanisms of monocyte-endothelial cell interactions in endothelial barrier dysfunction is more significant in patients with PVD compared to AAA. The purpose of this study is to assess patient peripheral blood monocyte adhesion molecules by flow cytometry and monocyte-induced endothelial barrier dysfunction by using an in vitro endothelial cell layer and electric cell-substrate impedance sensing system (ECIS). Methods Peripheral blood was collected from patients with either PVD (ABI<0.9, toe-arm index <0.8, or required lower extremity vascular intervention) or AAA (aortic diameter >3.0 cm). Monocytes were isolated from fresh whole blood using an accuspin-histopaque technique. The separated monocytes underwent flow cytometry analysis to evaluate expression levels of the cell membrane adhesion molecules: CD18, CD11a/b/c, and VLA-4. Endothelial cell function was assessed by adding monocytes to an endothelial monolayer on ECIS arrays and co-culturing overnight. Peak changes in trans-endothelial resistance were measured and compared between patient groups. Results Twenty-eight monocyte samples were analyzed for adhesion molecules (PVD: 19, AAA: 9) via flow cytometry and 11 patients were evaluated for endothelial dysfunction (PVD: 7, AAA: 4) via ECIS. There was no significant difference between risk factors among PVD and AAA patients except for age, where AAA patients were significantly older than PVD patients in both flow cytometry and ECIS groups (P=0.02, 0.01 respectively). There were significantly higher levels of adhesion molecules CD11a, CD18, and CD11c (averaged MFI P-values: 0.047, 0.038, 0.014, respectively) in PVD patients compared to AAA patients. No significant difference was found for CD11b and VLA-4 expression (P=0.21, 0.15 respectively). There was significantly more monocyte-endothelial cell dysfunction as a result of monocytes obtained from patients with PVD than from AAA, with a maximal effect seen at 15 hours after monocyte addition (P=0.032). Conclusions Patients with PVD have increased expression levels of certain monocyte adhesion molecules and greater monocyte-induced endothelial layer dysfunction when compared to patients with AAA. This may lead to other methods of targeted therapy to improve outcomes of these vascular patients.