A subpopulation of tissue remodeling monocytes stimulates revascularization of the ischemic limb.

Despite decades of effort aimed at developing clinically effective cell therapies, including mixed population mononuclear cells, to revascularize the ischemic limb, there remains a paucity of patient-based studies that inform the function and fate of candidate cell types. In this study, we showed that circulating proangiogenic/arteriogenic monocytes (PAMs) expressing the FcγIIIA receptor CD16 were elevated in patients with chronic limb-threatening ischemia (CLTI), and these amounts decreased after revascularization. Unlike CD16-negative monocytes, PAMs showed large vessel remodeling properties in vitro when cultured with endothelial cells and smooth muscle cells and promoted salvage of the ischemic limb in vivo in a mouse model of hindlimb ischemia. PAMs showed a propensity to migrate toward and bind to ischemic muscle and to secrete angiogenic/arteriogenic factors, vascular endothelial growth factor A (VEGF-A) and heparin-binding epidermal growth factor. We instigated a first-in-human single-arm cohort study in which autologous PAMs were injected into the ischemic limbs of five patients with CLTI. Greater than 25% of injected cells were retained in the leg for at least 72 hours, of which greater than 80% were viable, with evidence of enhanced large vessel remodeling in the injected muscle area. In summary, we identified up-regulation of a circulatory PAM subpopulation as an endogenous response to limb ischemia in CLTI and tested a potentially clinically relevant therapeutic strategy.

An update on the roles of immune system-derived microRNAs in cardiovascular diseases.

Cardiovascular diseases (CVD) are a leading cause of human death worldwide. Over the past two decades, the emerging field of cardioimmunology has demonstrated how cells of the immune system play vital roles in the pathogenesis of CVD. MicroRNAs (miRNAs) are critical regulators of cellular identity and function. Cell-intrinsic, as well as cell-extrinsic, roles of immune and inflammatory cell-derived miRNAs have been, and continue to be, extensively studied. Several 'immuno-miRNAs' appear to be specifically expressed or demonstrate greatly enriched expression within leucocytes. Identification of miRNAs as critical regulators of immune system signalling pathways has posed the question of whether and how targeting these molecules therapeutically, may afford opportunities for disease treatment and/or management. As the field of cardioimmunology rapidly continues to advance, this review discusses findings from recent human and murine studies which contribute to our understanding of how leucocytes of innate and adaptive immunity are regulated-and may also regulate other cell types, via the actions of the miRNAs they express, in the context of CVD. Finally, we focus on available information regarding miRNA regulation of regulatory T cells and argue that targeted manipulation of miRNA regulated pathways in these cells may hold therapeutic promise for the treatment of CVD and associated risk factors.

IL-6 and IL-8 Are Linked With Myeloid-Derived Suppressor Cell Accumulation and Correlate With Poor Clinical Outcomes in Melanoma Patients.

We sought to identify tumor-secreted factors that altered the frequency of MDSCs and correlated with clinical outcomes in advanced melanoma patients. We focused our study on several of the many factors involved in the expansion and mobilization of MDSCs. These were identified by measuring circulating concentrations of 13 cytokines and growth factors in stage IV melanoma patients (n = 55) and healthy controls (n = 22). Based on these results, we hypothesized that IL-6 and IL-8 produced by melanoma tumor cells participate in the expansion and recruitment of MDSCs and together would be predictive of overall survival in melanoma patients. We then compared the expression of IL-6 and IL-8 in melanoma tumors to the corresponding plasma concentrations and the frequency of circulating MDSCs. These measures were correlated with clinical outcomes. Patients with high plasma concentrations of either IL-6 (40%) or IL-8 (63%), or both (35%) had worse median overall survival compared to patients with low concentrations. Patients with low peripheral concentrations and low tumoral expression of IL-6 and IL-8 showed decreased frequencies of circulating MDSCs, and patients with low frequencies of MDSCs had better overall survival. We have previously shown that IL-6 is capable of expanding MDSCs, and here we show that MDSCs are chemoattracted to IL-8. Multivariate analysis demonstrated an increased risk of death for subjects with both high IL-6 and IL-8 (HR 3.059) and high MDSCs (HR 4.265). Together these results indicate an important role for IL-6 and IL-8 in melanoma patients in which IL-6 potentially expands peripheral MDSCs and IL-8 recruits these highly immunosuppressive cells to the tumor microenvironment. This study provides further support for identifying potential therapeutics targeting IL-6, IL-8, and MDSCs to improve melanoma treatments.

Immunosuppressive myeloid-derived suppressor cells are increased in splenocytes from cancer patients.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of myeloid cells that are increased in the peripheral blood of cancer patients and limit productive immune responses against tumors. Immunosuppressive MDSCs are well characterized in murine splenic tissue and are found at higher frequencies in spleens of tumor-bearing mice. However, no studies have yet analyzed these cells in parallel human spleens. We hypothesized that MDSCs would be increased in the spleens of human cancer patients, similar to tumor-bearing mice. We compared the frequency and function of MDSC subsets in dissociated human spleen from 16 patients with benign pancreatic cysts and 26 patients with a variety of cancers. We found that total MDSCs (Linneg CD11bpos CD33pos HLA-DRneg), granulocytic MDSCs (additional markers CD14neg CD15pos), and monocytic MDSCs (CD14pos CD15neg) were identified in human spleen. The monocytic subset was the most prominent in both spleen and peripheral blood and the granulocytic subset was expanded in the spleen relative to matched peripheral blood samples. Importantly, the frequency of CD15pos MDSCs in the spleen was increased in patients with cancer compared to patients with benign pancreatic cysts and was associated with a significantly increased risk of death and decreased overall survival. Finally, MDSCs isolated from the spleen suppressed T cell responses, demonstrating for the first time the functional capacity of human splenic MDSCs. These data suggest that the human spleen is a potential source of large quantities of cells with immunosuppressive function for future characterization and in-depth studies of human MDSCs.

Cyclooxygenase-2-dependent lymphangiogenesis promotes nodal metastasis of postpartum breast cancer.

Breast involution following pregnancy has been implicated in the high rates of metastasis observed in postpartum breast cancers; however, it is not clear how this remodeling process promotes metastasis. Here, we demonstrate that human postpartum breast cancers have increased peritumor lymphatic vessel density that correlates with increased frequency of lymph node metastases. Moreover, lymphatic vessel density was increased in normal postpartum breast tissue compared with tissue from nulliparous women. In rodents, mammary lymphangiogenesis was upregulated during weaning-induced mammary gland involution. Furthermore, breast cancer cells exposed to the involuting mammary microenvironment acquired prolymphangiogenic properties that contributed to peritumor lymphatic expansion, tumor size, invasion, and distant metastases. Finally, in rodent models of postpartum breast cancer, cyclooxygenase-2 (COX-2) inhibition during the involution window decreased normal mammary gland lymphangiogenesis, mammary tumor-associated lymphangiogenesis, tumor cell invasion into lymphatics, and metastasis. Our data indicate that physiologic COX-2-dependent lymphangiogenesis occurs in the postpartum mammary gland and suggest that tumors within this mammary microenvironment acquire enhanced prolymphangiogenic activity. Further, our results suggest that the prolymphangiogenic microenvironment of the postpartum mammary gland has potential as a target to inhibit metastasis and suggest that further study of the therapeutic efficacy of COX-2 inhibitors in postpartum breast cancer is warranted.

Microwave assisted synthesis, spectroscopic, electrochemical and DNA cleavage studies of lanthanide(III) complexes with coumarin based imines.

The present work stems from our interest in the synthesis, characterization and biological evaluation of lanthanide(III) complexes of a class of coumarin based imines which have been prepared by the interaction of hydrated lanthanide(III) chloride with the sodium salts of 3-acetylcoumarin thiosemicarbazone (ACTSZH) and 3-acetylcoumarin semicarbazone (ACSZH) in 1:3 molar ratio using thermal as well as microwave method. Characterization of the ligands as well as the metal complexes have been carried out by elemental analysis, melting point determinations, molecular weight determinations, magnetic moment, molar conductance, IR, (1)H NMR, (13)C NMR, electronic, EPR, X-ray powder diffraction and mass spectral studies. Spectral studies confirm ligands to be monofunctional bidentate and octahedral environment around metal ions. The redox behavior of one of the synthesized metal complex was investigated by cyclic voltammetry. Further, free ligands and their metal complexes have been screened for their antimicrobial as well as DNA cleavage activity. The results of these findings have been presented and discussed.