Arturo R. Maldonado

Characterization of endothelial progenitor cells mobilization following cutaneous wounding

Bone marrow (BM)‐derived endothelial progenitor cells (EPCs) are known to play an important role in neovascularization and wound healing. We investigated the temporal effects of cutaneous wounding on EPC surface markers within the peripheral blood and BM, and to better understand the role of the stromal cell‐derived factor‐1 alpha (SDF‐1α/CXCR4) axis on EPC mobilization after wounding. FVB/NJ mice were administered bilateral 8 mm circular full‐thickness skin wounds. Peripheral blood and BM were isolated at daily intervals postwounding through day 7 and analyzed for EPC mobilization characteristics and levels of SDF‐1α. Cutaneous wounding was found to cause a transient increase in EPC mobilization that peaked on day 3. In contrast, SDF‐1α protein within blood plasma was observed to significantly decrease on days 3, 4, and 7 following cutaneous wounding. BM levels of SDF‐1α protein decreased to a nadir on day 3, the same day as peak mobilization was observed to occur. The decrease in BM SDF‐1α protein levels was also associated with a decrease in SDF‐1α mRNA suggesting transcriptional down‐regulation as a contributing factor. This study for the first time characterizes EPC mobilization following cutaneous wounding in mice and supports a major role for the SDF‐1α/CXCR4 axis in regulating mobilization within the BM, without evidence for systemic increases in SDF‐1α.

Molecular engineering and validation of an oncolytic herpes simplex virus type 1 transcriptionally targeted to midkine-positive tumors

Expression profile analyses of midkine (MDK), a multifunctional protein important in development but repressed postnataly, indicate that it is highly expressed in approximately 80% of adult carcinomas and many childhood cancers including malignant peripheral nerve sheath tumors (MPNST). In the present study, we sought to leverage its selective expression to develop a novel oncolytic herpes simplex virus (oHSV) capable of targeting developmentally primitive cancers that express MDK.

The differential effect of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers with respect to foot ulcer and limb amputation in those with diabetes.

Diabetic foot ulcers (DFU) or lower extremity amputation (LEA) are complications of diabetes. In those with diabetes, angiotensin‐converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) are commonly used to prevent the progression of kidney disease. Recent studies have indicated that angiotensin may affect angiogenesis and wound repair. Our goal was to evaluate in those with diabetes the likelihood of developing a DFU or LEA among users of ACEi or ARB using a retrospective cohort design of general practices in the United Kingdom. We studied 40,342 individuals at least 35 years of age with diabetes who were first prescribed ACEi or ARB between 1995 and 2006. A total of 35,153 individuals were treated with ACEi, 12,437 individuals with ARB, and 7,310 both. The hazard ratio for DFU was 0.50 (95% confidence intervals: 0.43, 0.59), showing an increased risk of DFU for those using ACEi vs. ARB. The hazard ratio for LEA was 0.72 (0.48, 1.01). However, among those with lower extremity peripheral arterial disease the hazard ratio was 0.45 (0.22, 0.91) for the new onset of a LEA. In conclusion, among those with diabetes, exposure to ACEi as compared with ARB increases the risk of developing a DFU or LEA.

Compensatory lung growth in NOS3 knockout mice suggests synthase isoform redundancy.

Nitric oxide synthase 3 (NOS3) produces nitric oxide (NO) in endothelial cells, which stimulates cyclic guanosine monophosphate (cGMP) production and thereby mediates pulmonary vasodilation. Inhibition of cGMP enzymatic cleavage by sildenafil might be involved in lung growth stimulating processes in pulmonary hypoplasia. The aim of this study was to discover insights into the transcriptional regulation of NOS3 in a mouse model of compensatory lung growth (CLG). CLG was studied in wild type animals (WT) and NOS3 knockout mice (NOS3-/-) by dry weight, DNA, and protein quantification as well as relative quantification of NOS mRNA. All assessments were done on adult female mice, 10 days after left pneumonectomy (PNX) or sham thoracotomy. Weight ratios of right NOS3-/- lungs were no different than controls. There was a compensatory increase in DNA and a noncompensating increase in protein ratios in NOS3-/- mice compared with controls. Pharmacological knockdown with the pan-NOS inhibitor l-NAME (nitro-arginine methyl ester) reduced CLG by only 8% compared with the d-NAME treated control mice. Relative quantification of lung mRNA revealed no up-regulation of NOS3 expression in WT lungs after PNX, but NOS3-/- lungs showed a 2.6-fold higher inducible NOS2 expression compared with shams. These data suggest that NOS3 loss of function alone does not impair CLG in mice, possibly because of redundancy mechanisms involving NOS2.