A new positron emission tomography (PET) tracer, composed of 18F labeled maltohexaose (MH18F), can image bacteria in vivo with a sensitivity and specificity that is orders of magnitude better than fluorodeoxyglucose (18FDG). MH18F can detect early stage infections composed of as few as 105 E.coli colony forming units (CFUs), and can identify drug resistance in bacteria in vivo. MH18F has the potential to improve the diagnosis of bacterial infections given its unique combination of high specificity and sensitivity for bacteria.

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Abstract-Angiotensin II (Ang II) is implicated in the proinflammatory process in various disease situations. Thus, we sought to determine the role of Ang II in early inflammation-induced fibrosis of pressure-overloaded (PO) hearts. PO was induced by suprarenal aortic constriction (AC) at day 0 in male Wistar rats, and they were orally administered 0.1 mg/kg per day candesartan every day from day Ϫ7. This was the maximum dose of candesartan that did not change arterial pressure in hypertensive rats with AC (AC rats). In AC rats, cardiac angiotensin-converting enzyme (ACE) activity was transiently enhanced after day 1 and peaked at day 3, declining to lower levels by day 14, whereas serum ACE activity was not changed. In AC rats, PO induced early fibroinflammatory changes (monocyte chemoattractant factor [MCP]-1 and transforming growth factor [TGF]-␤ expression, perivascular macrophage accumulation, and fibroblast proliferation), and thereafter, left ventricular hypertrophy developed, featuring myocyte hypertrophy, intramyocardial arterial wall thickening, and perivascular and interstitial fibroses. Candesartan suppressed the induction of MCP-1 and TGF-␤ and reduced macrophage accumulation and fibroblast proliferation in PO hearts. Candesartan significantly prevented perivascular and interstitial fibrosis. However, candesartan did not affect myocyte hypertrophy and arterial wall thickening. In conclusion, a subdepressor dose of candesartan prevented the MCP-1-mediated inflammatory process and reactive myocardial fibrosis in PO hearts. Ang II might play a key role in reactive fibrosis in hypertensive hearts, independent of arterial pressure changes.

Abstract-Recently, we have shown that in rats with a suprarenal abdominal aortic constriction (AC), pressure overload induces early perivascular fibro-inflammatory changes (transforming growth factor [TGF]-␤ induction and fibroblast proliferation) within the first week after AC and then causes the development of cardiac remodeling (myocyte hypertrophy and reactive myocardial fibrosis) associated with diastolic dysfunction. Intercellular adhesion molecule (ICAM)-1 is implicated in the recruitment of leukocytes, especially macrophages, in various inflammatory situations. Thus, we sought to investigate the causal relation of ICAM-1 to macrophage recruitment and cardiac remodeling in AC rats. In AC rats, immunoreactive ICAM-1 was observed transiently on endothelial cells of the intramyocardial coronary arterioles after day 1, with a peak at day 3, returning to baseline by day 7. Also, ED1 ϩ macrophage accumulation was found in the area adjacent to the arteries expressing ICAM-1. Chronic treatment with an anti-ICAM-1 neutralizing antibody, but not with control IgG, remarkably reduced the accumulations of macrophages and proliferative fibroblasts and inhibited the upregulation of TGF-␤ expression. Furthermore, the neutralizing antibody significantly prevented myocardial fibrosis without affecting arterial pressure and left ventricular and myocyte hypertrophy. In conclusion, ICAM-1 expression was induced by pressure overload in the intramyocardial arterioles, and triggered perivascular macrophage accumulation. In pressure-overloaded hearts, a crucial role in ICAM-1-mediated macrophage accumulation was suggested in the development of myocardial fibrosis, through TGF-␤ induction and fibroblast activation.

Mesenchymal stem cells (MSCs) are the pluripotent cells, which enter the circulation and home to sites of tissue injury or inflammation. MSCs are highlighted as a potential cell vector for gene therapy. In this study, we investigated whether transplanted allogeneic MSCs preferentially accumulate in the lung in rats with pulmonary hypertension (PH) and if so to determine the efficacy of MSC-based prostacyclin synthase (PCS) gene therapy for PH. PH was induced in Lewis rats by injecting monocrotaline at 7-weeks-old (week 0). MSCs were obtained by culturing bone marrow mononuclear cells. Allogeneic MSCs were intravenously transplanted at week 2 when moderate PH had been established. PH enhanced indium-111-oxine-labeled MSC accumulation in the lungs, but not in other organs, 2.5-times and 6-times, 1 and 14 days after transplantation, respectively. Transplantation of MSCs transduced with PCS (PSC-MSCs), but not with GFP (GFP-MSCs), reduced PH, pulmonary arterial thickening, and RV hypertrophy at week 4. The lung prostacyclin production was impaired in PH rats, which was restored and maintained for long time by PCS-MSCs, but not by GFP-MSCs. The survival rate at week 7 was 100% in PCS-MSC-transplanted PH rats, whereas they were 38 and 44% in PH rats and GFP-MSC-transplanted PH rats, respectively. In conclusion, the gene-engineered MSCs would be a suitable cell vector for gene delivery specifically to the PH lung. The allogeneic PCS-MSC transplantation attenuated PH and cardiovascular remodeling, and improved the prognosis in PH rats. The MSC-based PCS gene therapy may be a promising strategy for PH treatment.