James J. Yang

Systemic Administration of Exosomes Released from Mesenchymal Stromal Cells Promote Functional Recovery and Neurovascular Plasticity After Stroke in Rats

Here, for the first time, we test a novel hypothesis that systemic treatment of stroke with exosomes derived from multipotent mesenchymal stromal cells (MSCs) promote neurovascular remodeling and functional recovery after stroke in rats. Adult male Wistar rats were subjected to 2 hours of middle cerebral artery occlusion (MCAo) followed by tail vein injection of 100 μg protein from MSC exosome precipitates or an equal volume of vehicle phosphate-buffered saline (PBS) (n = 6/group) 24 hours later. Animals were killed at 28 days after stroke and histopathology and immunohistochemistry were employed to identify neurite remodeling, neurogenesis, and angiogenesis. Systemic administration of MSC-generated exosomes significantly improved functional recovery in stroke rats compared with PBS-treated controls. Axonal density and synaptophysin-positive areas were significantly increased along the ischemic boundary zone of the cortex and striatum in MCAo rats treated with exosomes compared with PBS control. Exosome treatment significantly increased the number of newly formed doublecortin (a marker of neuroblasts) and von Willebrand factor (a marker of endothelial cells) cells. Our results suggest that intravenous administration of cell-free MSC-generated exosomes post stroke improves functional recovery and enhances neurite remodeling, neurogenesis, and angiogenesis and represents a novel treatment for stroke.

Grilled Meat Consumption and PhIP-DNA Adducts in Prostate Carcinogenesis

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is the major heterocyclic amine generated from cooking meats at high temperatures, and dietary exposures have been shown to induce prostate cancer in rats. PhIP derives its carcinogenic potential through the formation of PhIP-DNA adducts. The purpose of this study was to examine whether self-reported consumption and preparation doneness of grilled meats were associated with PhIP-DNA adduct levels in prostate epithelial cells. The study population consisted of 268 African-American and Caucasian men who underwent radical prostatectomy for prostate cancer. PhIP-DNA adducts in tumor and adjacent nontumor cells were measured using immunohistochemical methods, and dietary meat intake information was based on food frequency questionnaires. Data were analyzed using multivariate linear regression models. After adjusting for age at prostatectomy and race, grilled meat consumption (P = 0.002) was significantly associated with higher adduct levels in tumor cells, but this association seemed to be primarily due to consumption of grilled red meats (P = 0.001) as opposed to grilled white meat consumption (P = 0.15). Among the specific food items, grilled hamburger consumption had the most significant association with adduct level in tumor cells (P = 0.002). Similar trends in positive associations with grilled meat consumption and adduct levels were observed in nontumor cells, but none of these associations reached statistical significance. Our results suggest that dietary interventions targeted at lower consumption of grilled red meats may reduce prostate cancer risk via the PhIP prostate carcinogenic pathway. (Cancer Epidemiol Biomarkers Prev 2007;16(4):803–8)

Decreased Endogenous Levels of Ac-SDKP Promote Organ Fibrosis

There is convincing evidence that chronic treatment with N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), a peptide normally found in tissues and biological fluids, reduces collagen deposition in the heart and kidneys of hypertensive rats and rats with myocardial infarction. However, it is not known whether endogenous Ac-SDKP at basal concentrations has any physiological function related to collagen deposition. Prolyl oligopeptidase is responsible for release of Ac-SDKP from its precursor thymosin-β4. When we treated rats with a specific oral rolyl oligopeptidase inhibitor, Ac-SDKP decreased significantly in the plasma, heart, and kidney. In the present study, we tested the hypothesis that endogenous Ac-SDKP at basal levels plays a physiological role, antagonizing and/or preventing excessive collagen deposition. We studied whether chronic blockade of Ac-SDKP promotes collagen accumulation and/or accelerates this process in the presence of a profibrotic stimulus such as angiotensin II. We found that decreased basal levels of Ac-SDKP increased cardiac and renal perivascular fibrosis and promoted glomerulosclerosis. Moreover, in the presence of angiotensin II decreasing basal levels of Ac-SDKP accelerated interstitial cardiac fibrosis attributable to an increase in cells that produce collagen. We concluded that Ac-SDKP participates in the regulation of collagen content under normal conditions. We believe this is the first study showing that this peptide plays a physiological role at basal concentrations, preventing organ collagen accumulation.

Role of the B1 Kinin Receptor in the Regulation of Cardiac Function and Remodeling After Myocardial Infarction

Kinins exert cardioprotective effects via 2 G-protein-coupled receptors, B1 and B2. Using B1 kinin receptor gene knockout mice (B1−/−), we tested the hypotheses that the B1 receptor plays an important role in preservation of cardiac function, whereas lack of B1 may accelerate cardiac remodeling and dysfunction after myocardial infarction, and that B2 receptors may compensate for lack of B1, whereas blockade of B2 receptors in B1−/− mice may cause further deterioration of cardiac function and remodeling. Female B1−/− mice and wild-type controls (C57BL/6J, B1+/+) underwent sham surgery or myocardial infarction and were treated with either vehicle or B2-antagonist (icatibant, 500 &mgr;g/kg per day, subcutaneous) for 8 weeks. We found that in sham myocardial infarction, B1−/− mice had a larger left ventricular diastolic chamber dimension both initially and at 4 to 8 weeks compared with B1+/+. Left ventricular mass and myocyte size were also larger in B1−/− with sham operation than in B1+/+, although cardiac function did not differ between strains. After myocardial infarction, cardiac remodeling and function were similar in both strains, although B1−/− mice tended to have lower blood pressure. Blockade of B2 receptors tended to worsen cardiac remodeling and dysfunction in B1−/− but not in B1+/+. These results may suggest that B2 receptors play an important role in compensating for lack of B1 receptors in mice with myocardial infarction. Dual blockade of both B1 and B2 eliminates this compensation, leading to further deterioration of cardiac dysfunction and remodeling after myocardial infarction.

Local angiotensin II aggravates cardiac remodeling in hypertension

Angiotensin II (ANG II) contributes to hypertension, cardiac hypertrophy, fibrosis, and dysfunction; however, it is difficult to separate the cardiac effect of ANG II from its hemodynamic action in vivo. To overcome the limitations, we used transgenic mice with cardiac-specific expression of a transgene fusion protein that releases ANG II from cardiomyocytes (Tg-ANG II) and treated them with deoxycorticosterone acetate (DOCA)-salt to suppress their systemic renin-angiotensin system. Using this unique model, we tested the hypothesis that cardiac ANG II, acting on the angiotensin type 1 receptor (AT(1)R), increases inflammation, oxidative stress, and apoptosis, accelerating cardiac hypertrophy and fibrosis. Male Tg-ANG II mice and their nontransgenic littermates (n-Tg) were uninephrectomized and divided into the following three groups: 1) vehicle-treated normotensive controls; 2) DOCA-salt; and 3) DOCA-salt + valsartan (AT(1)R blocker).Under basal conditions, systolic blood pressure (SBP) and cardiac phenotypes were similar between strains. In DOCA-salt hypertension, SBP increased similarly in both n-Tg and Tg-ANG II, and cardiac function did not differ between strains; however, Tg-ANG II had 1) greater ventricular hypertrophy as well as interstitial and perivascular fibrosis; 2) a higher number of deoxynucleotidyl-transferase-mediated dUTP nick end labeling-positive cells and infiltrating macrophages; 3) increased protein expression of NADPH oxidase 2 and transforming growth factor-β(1); and 4) downregulation of phosphatidylinositol 3-kinase (PI 3-kinase) and protein kinase B (Akt) phosphorylation. Valsartan partially reversed these effects in Tg-ANG II but not in n-Tg. We conclude that, when hemodynamic loading conditions remain unchanged, cardiac ANG II does not alter heart size or cardiac functions. However, in animals with hypertension, cardiac ANG II, acting via AT(1)R, enhances inflammation, oxidative stress, and cell death (most likely via downregulation of PI 3-kinase and Akt), contributing to cardiac hypertrophy and fibrosis.

5-Fluorouracil treatment of problematic scars

Background: Keloids and hypertrophic scars can be uncomfortable, disfiguring, and aesthetically undesirable. Anecdotal reports suggest that low-dose intralesional fluorouracil can be used to treat these undesirable scars. Methods: Using a prospective case series protocol, both keloid and hypertrophic scar patients were included. Keloid patients underwent excision followed by a series of treatments with intralesional 5-fluorouracil into the healing scar to prevent recurrence (n = 32). The hypertrophic scar patients were treated with the same series of injections without scar excision to both control symptoms and improve scar appearance (n = 21). The primary outcome measures were scar volume and a symptom questionnaire. Patients were followed for 1 year after completing the injection treatments. Results: In the keloid group, the recurrence rate was 19 percent at 1-year follow-up for this group of patients who had failed previous corticosteroid injection therapy. In the hypertrophic scar group, 14 percent did not respond to the series of injections. In this group, there was a median volume decrease of 50 percent maintained for 1 year after injection therapy was terminated. Conclusions: Intralesional fluorouracil is a safe and effective means of controlling problem scars in terms of both recurrence and symptom control. Benefits were maintained for at least 1 year after completion of therapy. Intralesional 5-fluorouracil should be considered another option for patients suffering from problematic scars.

Differences in Allergic Sensitization by Self-reported Race and Genetic Ancestry

BACKGROUND Many allergic conditions occur more frequently in African American patients when compared with white patients; however, it is not known whether this represents genetic predisposition or disparate environmental exposures. OBJECTIVE We sought to assess the relationship of self-reported race and genetic ancestry to allergic sensitization. METHODS We included 601 women enrolled in a population-based cohort study whose self-reported race was African American or white. Genetic ancestry was estimated by using markers that differentiate West African and European ancestry. We assessed the relationship between allergic sensitization (defined as > or =1 allergen-specific IgE results) and both self-reported race and genetic ancestry. Regression models adjusted for sociodemographic variables, environmental exposures, and location of residence. RESULTS The average proportion of West African ancestry in African American participants was 0.69, whereas the mean proportion of European ancestry in white participants was 0.79. Self-reported African American race was associated with allergic sensitization when compared with those who reported being white (adjusted odds ratio, 2.19; 95% CI, 1.22-3.93), even after adjusting for other variables. Genetic ancestry was not significantly associated with allergic sensitization after accounting for location of residence (adjusted odds ratio, 2.09 for urban vs suburban residence; 95% CI, 1.32-3.31). CONCLUSION Self-reported race and location of residence appeared to be more important predictors of allergic sensitization when compared with genetic ancestry, suggesting that the disparity in allergic sensitization by race might be primarily a result of environmental factors rather than genetic differences.

Associations between Smoking, Polymorphisms in Polycyclic Aromatic Hydrocarbon (PAH) Metabolism and Conjugation Genes and PAH-DNA Adducts in Prostate Tumors Differ by Race

Polycyclic aromatic hydrocarbon (PAH)-DNA adducts may induce mutations that contribute to carcinogenesis. We evaluated potential associations between smoking and polymorphisms in PAH metabolism [CYP1A1 Ile462Val, CYP1B1 Ala119Ser and Leu432Val, microsomal epoxide hydrolase (mEH) Tyr113His and His139Arg, CYP3A4 A(−392)G] and conjugation [glutathione S-transferase (GST) M1 null deletion, GSTP1 Ile105Val] genes and PAH-DNA adduct levels (measured by immunohistochemistry) in tumor and nontumor prostate cells in 400 prostate cancer cases. Although no statistically significant associations were observed in the total sample, stratification by ethnicity revealed that Caucasian ever smokers compared with nonsmokers had higher adduct levels in tumor cells (mean staining intensity in absorbance units ± SE, 0.1748 ± 0.0052 versus 0.1507 ± 0.0070; P = 0.006), and Caucasians carrying two mEH 139Arg compared with two 139His alleles had lower adducts in tumor (0.1320 ± 0.0129 versus 0.1714 ± 0.0059; P = 0.006) and nontumor (0.1856 ± 0.0184 versus 0.2291 ± 0.0085; P = 0.03) cells. African Americans with two CYP1B1 432Val compared with two 432Ile alleles had lower adducts in tumor cells (0.1600 ± 0.0060 versus 0.1970 ± 0.0153; P = 0.03). After adjusting for smoking status, carrying the putative “high-risk” genotype combination, the faster metabolism of PAH-epoxides to PAH-diol-epoxides (CYP1B1 432Val/Val and mEH 139Arg/Arg) with lower PAH-diol-epoxide conjugation (GSTP1 105Ile/Ile), was associated with increased adducts only in Caucasian nontumor cells (0.2363 ± 0.0132 versus 0.1920 ± 0.0157; P= 0.05). We present evidence, for the first time in human prostate that the association between smoking and PAH-DNA adducts differs by race and is modified by common genetic variants. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1236–45)

Safety and efficacy of erbium-doped yttrium aluminum garnet fractionated laser for treatment of acne scars in type IV to VI skin.

BACKGROUND Ablative resurfacing lasers are effective for treatment of acne scars, but they have a high risk of complications. Fractional lasers have less severe side effects but more moderate efficacy than ablative devices. Studies were performed in individuals with Fitzpatrick skin type I to VI. OBJECTIVE To determine the efficacy and safety of an erbium 1,550‐nm fractional laser in the treatment of facial acne scars in Fitzpatrick skin types IV to VI. METHODS We conducted a prospective, single‐blind, randomized trial in patients with acne scars (n=15), skin type IV to VI, with a 1,550‐nm erbium fractionated laser. Patients were divided into two groups; one was treated with 10 mJ and the other with 40 mJ. Five monthly laser sessions were performed. A patient questionnaire was distributed. RESULTS There was a significant improvement in the acne scarring and overall appearance (p<.001). No significant difference was found between 10 and 40 mJ. Patients were highly satisfied with their results. Significant postinflammatory hyperpigmentation was seen; pain was significantly higher in darker skin. CONCLUSIONS Fractional photothermolysis is effective for the treatment of acne scars, but practition‐ers should be aware of the higher incidence of pain and postinflammatory hyperpigmentation in individuals with skin types IV to VI. The study was funded by Reliant Technologies, Inc., which participated in the study design. Galderma (Ft. Worth, TX) provided Tri‐luma cream and GlaxoSmithKline (Research Triangle Park, NC) provided valacyclovir (Valtrex).

The GENESIS Project (GENeralized Early Sepsis Intervention Strategies) A Multicenter Quality Improvement Collaborative

Background: Improved outcomes for severe sepsis and septic shock have been consistently observed with implementation of early best practice intervention strategies or the 6-hour resuscitation bundle (RB) in single-center studies. This multicenter study examines the in-hospital mortality effect of GENeralized Early Sepsis Intervention Strategies (GENESIS) when utilized in community and tertiary care settings. Methods: This study was comprised of 2 strategies to assess treatment. The first was a prospective before-and-after observational comparison of historical controls to patients receiving the RB after implementation of GENESIS in 4 community and 4 tertiary hospitals. The second was a concurrent examination comparing patients not achieving all components of the RB to those achieving all components of the RB in 1 community and 2 tertiary care hospitals after implementation of GENESIS. These 4 subgroups merged to comprise a control (historical controls treated before GENESIS and RB not achieved after GENESIS) group and treatment (patients treated after GENESIS and RB achieved after GENESIS) group for comparison. Results: The control group comprised 1554 patients not receiving the RB (952 before GENESIS and 602 RB not achieved after GENESIS). The treatment group comprised 4801 patients receiving the RB (4109 after GENESIS and 692 RB achieved after GENESIS). Patients receiving the RB (treatment group) experienced an in-hospital mortality reduction of 14% (42.8%-28.8%, P < .001) and a 5.1 day decrease in hospital length of stay (20.7 vs 15.6, P < .001) compared to those not receiving the RB (control group). Similar mortality reductions were seen in the before-and-after (43% vs 29%, P < .001) or concurrent RB not achieved versus achieved (42.5% vs 27.2%, P < .001) subgroup comparisons. Conclusions: Patients with severe sepsis and septic shock receiving the RB in community and tertiary hospitals experience similar and significant reductions in mortality and hospital length of stay. These findings remained consistent when examined in both before-and-after and concurrent analyses. Early sepsis intervention strategies are associated with 1 life being saved for every 7 treated.