Pro-inflammatory angiogenesis is mediated by p38 MAP kinase.

Chronic inflammation is tightly linked to diseases associated with endothelial dysfunction including aberrant angiogenesis. To better understand the endothelial role in pro-inflammatory angiogenesis, we analyzed signaling pathways in continuously activated endothelial cells, which were either chronically exposed to soluble TNF or the reactive oxygen species (ROS) generating H2O2, or express active transmembrane TNF. Testing in an in vitro capillary sprout formation assay, continuous endothelial activation increased angiogenesis dependent on activation of p38 MAP kinase, NADPH oxidase, and matrix metalloproteinases (MMP). p38 MAP kinase- and MMP-9-dependent angiogenesis in our assay system may be part of a positive feed forward autocrine loop because continuously activated endothelial cells displayed up-regulated ROS production and subsequent endothelial TNF expression. The pro-angiogenic role of the p38 MAP kinase in continuously activated endothelial cells was in stark contrast to the anti-angiogenic activity of the p38 MAP kinase in unstimulated control endothelial cells. In vivo, using an experimental prostate tumor, pharmacological inhibition of p38 MAP kinase demonstrated a significant reduction in tumor growth and in vessel density, suggesting a pro-angiogenic role of the p38 MAP kinase in pathological angiogenesis in vivo. In conclusion, our results suggest that continuous activation of endothelial cells can cause a switch of the p38 MAP kinase from anti-angiogenic to pro-angiogenic activities in conditions which link oxidative stress and autocrine TNF production.

Robust functional vascular network formation in vivo by cooperation of adipose progenitor and endothelial cells.

Rapid induction and maintenance of blood flow through new vascular networks is essential for successfully treating ischemic tissues and maintaining function of engineered neo-organs. We have previously shown that human endothelial progenitor cells (EPCs) form functioning vessels in mice, but these are limited in number and persistence; and also that human adipose stromal cells (ASCs) are multipotent cells with pericytic properties which can stabilize vascular assembly in vitro. In this study, we tested whether ASCs would cooperate with EPCs to coassemble vessels in in vivo implants. Collagen implants containing EPCs, ASCs, or a 4:1 mixture of both were placed subcutaneously into NOD/SCID mice. After a range of time periods, constructs were explanted and evaluated with regard to vascular network assembly and cell fate; and heterotypic cell interactions were explored by targeted molecular perturbations. The density and complexity of vascular networks formed by the synergistic dual-cell system was many-fold higher than found in implants containing either ASCs or EPCs alone. Coimplantation of ASCs and EPCs with either pancreatic islets or adipocytes produced neoorgans populated by these parenchymal cells, as well as by chimeric human vessels conducting flow. This study is the first to demonstrate prompt and consistent assembly of a vascular network by human ASCs and endothelial cells and vascularization by these cells of parenchymal cells in implants. Mixture of these 2 readily available, nontransformed human cell types provides a practical approach to tissue engineering, therapeutic revascularization, and in vivo studies of human vasculogenesis.

Precocious puberty and large multicystic ovaries in young girls with primary hypothyroidism.

OBJECTIVE: To describe 2 cases of primary hypothyroidism, precocious puberty, large multicystic ovaries, possible diagnostic dilemma, unilateral oophorectomies, and subsequent response to levothyroxine replacement therapy. METHODS: We present the clinical, biochemical, radiologic, and histopathologic findings in 2 patients with rare cases of Van Wyk-Grumbach syndrome and megaovaries, who underwent unilateral oophorectomy. RESULTS: Two patients, an 8-year-old girl and a 3-year-old girl (cases 1 and 2, respectively), were referred to our center. Both patients presented with precocious puberty and vaginal bleeding and had undergone unilateral oophorectomy before referral. In the first patient (case 1), the surgical intervention was a consequence of torsion of the left megaovary, necessitating emergency oophorectomy. Oophorectomy in the second patient (case 2) was a result of initial diagnostic confusion, inasmuch as a sexcord stromal tumor was suspected. A detailed history, physical examination, and laboratory results pointed toward primary hypothyroidism due to Hashimoto's thyroiditis and thyroid dysgenesis, respectively. Serial ultrasound studies of the abdomen and pelvis revealed large multicystic ovaries, with progressive enlargement (including regrowth from an apparent ovarian "postsurgical remnant"). Both patients responded dramatically after initiation of levothyroxine replacement therapy, with no further vaginal bleeding and reversal of megaovary to normal size (in case 1). CONCLUSION: In a highly selected minority of children with untreated primary hypothyroidism, there is development of precocious puberty and progressively enlarging multicystic ovaries. The precise endocrine, neuroanatomic, and neurophysiologic bases for this phenomenon are unclear. Nevertheless, the entire clinicopathologic picture, including giant ovaries, dramatically reverts to normal status with the restoration of a euthyroid state by means of simple levothyroxine replacement therapy.