The biophysical properties of Basal lamina gels depend on the biochemical composition of the gel

The migration of cells within a three-dimensional extracellular matrix (ECM) depends sensitively on the biochemical and biophysical properties of the matrix. An example for a biological ECM is given by reconstituted basal lamina gels purified from the Engelbreth-Holm-Swarm sarcoma of mice. Here, we compare four different commercial variants of this ECM, which have all been purified according to the same protocol. Nevertheless, in those gels, we detect strong differences in the migration behavior of leukocyte cells as well as in the Brownian motion of nanoparticles. We show that these differences correlate with the mechanical properties and the microarchitecture of the gels which in turn arise from small variations in their biochemical composition.

Components of the plasminogen activation system promote engraftment of porous polyethylene biomaterial via common and distinct effects

Rapid fibrovascularization is a prerequisite for successful biomaterial engraftment. In addition to their well-known roles in fibrinolysis, urokinase-type plasminogen activator (uPA) and tissue plasminogen activator (tPA) or their inhibitor plasminogen activator inhibitor-1 (PAI-1) have recently been implicated as individual mediators in non-fibrinolytic processes, including cell adhesion, migration, and proliferation. Since these events are critical for fibrovascularization of biomaterial, we hypothesized that the components of the plasminogen activation system contribute to biomaterial engraftment. Employing in vivo and ex vivo microscopy techniques, vessel and collagen network formation within porous polyethylene (PPE) implants engrafted into dorsal skinfold chambers were found to be significantly impaired in uPA-, tPA-, or PAI-1-deficient mice. Consequently, the force required for mechanical disintegration of the implants out of the host tissue was significantly lower in the mutant mice than in wild-type controls. Conversely, surface coating with recombinant uPA, tPA, non-catalytic uPA, or PAI-1, but not with non-catalytic tPA, accelerated implant vascularization in wild-type mice. Thus, uPA, tPA, and PAI-1 contribute to the fibrovascularization of PPE implants through common and distinct effects. As clinical perspective, surface coating with recombinant uPA, tPA, or PAI-1 might provide a novel strategy for accelerating the vascularization of this biomaterial.

The impact of cysteine-rich intestinal protein 1 (CRIP1) in human breast cancer

Background

CRIP1 (cysteine-rich intestinal protein 1) has been found in several tumor types, its prognostic impact and its role in cellular processes, particularly in breast cancer, are still unclear.

Methods

To elucidate the prognostic impact of CRIP1, we analyzed tissues from 113 primary invasive ductal breast carcinomas using immunohistochemistry. For the functional characterization of CRIP1, its endogenous expression was transiently downregulated in T47D and BT474 breast cancer cells and the effects analyzed by immunoblotting, WST-1 proliferation assay and invasion assay.

Results

We found a significant correlation between CRIP1 and HER2 (human epidermal growth factor receptor 2) expression levels (p = 0.016) in tumor tissues. In Kaplan Meier analyses, CRIP1 expression was significantly associated with the distant metastases-free survival of patients, revealing a better prognosis for high CRIP1 expression (p = 0.039). Moreover, in multivariate survival analyses, the expression of CRIP1 was an independent negative prognostic factor, along with the positive prognosticators nodal status and tumor size (p = 0.029). CRIP1 knockdown in the T47D and BT474 breast cancer cell lines led to the increased phosphorylation of MAPK and Akt, to the reduced phosphorylation of cdc2, and to a significantly elevated cell proliferation in vitro (p < 0.001). These results indicate that reduced CRIP1 levels may increase cell proliferation and activate cell growth. In addition, CRIP1 knockdown increased cell invasion in vitro.

Conclusions

Because the lack of CRIP1 expression in breast cancer tissue is significantly associated with a worse prognosis for patients and low endogenous CRIP1 levels in vitro increased the malignant potential of breast cancer cells, we hypothesize that CRIP1 may act as a tumor suppressor in proliferation and invasion processes. Therefore, CRIP1 may be an independent prognostic marker with significant predictive power for use in breast cancer therapy.

Pressor reactivity, ethnicity, and 24-hour ambulatory monitoring in children from hypertensive families

We assessed blood pressure responses of a multiethnic (Black and White) sample of 120 children of hypertensive families to orthostasis, video game, forehead cold, and dynamic exercise, and monitored the children's ambulatory pressure 24 hours later. Thirteen children were studied twice (1-year stability). The Black children exhibited higher 24-hour ambulatory systolic and diastolic pressures than the White children. Regardless of ethnicity, peak and mean systolic pressures during each task were generally positively correlated with mean systolic pressure while the children were awake and asleep. Associations between diastolic pressor responses and ambulatory measurements were somewhat dependent upon ethnicity and task. Relatively few reactivity-ambulatory correlations were significant, using pressor reactivity change scores. The children who participated twice exhibited significant 1-year stability for most ambulatory and pressor measurements. Children's pressor responses to laboratory tasks may generalize to the natural environment.

Ethnic differences in the myocardial and vascular reactivity to stress in normotensive girls

Cardiovascular reactivity to stress has been proposed as a mechanism partially responsible for the increased prevalence of essential hypertension in African-Americans compared with whites. However, few studies have examined ethnic differences in cardiovascular reactivity among women. The present study evaluated potential ethnic differences in the cardiovascular reactivity to three laboratory stressors (postural change, video game challenge, forehead cold stimulation). The sample consisted of 171 normotensive girls (74 whites, 97 African-Americans) with a mean age of 11.1 +/- 2.7 years, all with positive family histories of essential hypertension. African-American girls showed higher resting diastolic blood pressures and higher resting total peripheral resistance compared with white girls. African-American girls also exhibited higher peak responses in systolic and diastolic blood pressure and total peripheral resistance and lower cardiac index responses during video game challenge and forehead cold stressor. The findings extend previous observations of ethnic differences in blood pressure reactivity to stress and indicate that concomitant increases in total peripheral resistance appear to account for the greater blood pressure reactivity in African-American girls.

Determinants of left ventricular mass in normotensive children

Left ventricular hypertrophy has been shown to be an independent predictor of cardiovascular morbidity and mortality. Few studies have examined the determinants of left ventricular mass (LVM) in normotensive children. Eight-four healthy children, blacks and whites, girls and boys, between 6 and 18 years of age, all with positive family histories of essential hypertension, participated in the study. Demographic and anthropometric characteristics, physical activity, and hemodynamic responses at rest and in response to the stress of forehead cold stimulation and a challenging video game were related to M-mode echocardiographic determined LVM indexed by two indices of body habitus. Hierarchical stepwise multiple regression analysis indicated that the significant independent correlates of LVM per body surface area were gender (boys were greater), baseline systolic blood pressure and heart rate, a physical activity index (sweat episodes per week) and peak systolic blood pressure responses to the forehead cold stressor (final model r2 = 0.49). For LVM/height2.7 significant independent correlates were adiposity index (weight z score--height z score), gender (boys were greater), age, resting systolic pressure, and systemic vascular resistance reactivity to forehead cold stimulation (final model r2 = 0.42). These findings with normotensive children corroborate other findings that have typically involved hypertensive children, indicating that resting heart rate and systolic pressure, gender, and adiposity are early determinants of LVM indices in children. In addition, the current findings indicate that hemodynamic responses to stress also appear to play a role in the early development of LVM.(ABSTRACT TRUNCATED AT 250 WORDS)