Delayed wound repair in sepsis is associated with reduced local pro-inflammatory cytokine expression

Sepsis is one of the main causes for morbidity and mortality in hospitalized patients. Moreover, sepsis associated complications involving impaired wound healing are common. Septic patients often require surgical interventions that in-turn may lead to further complications caused by impaired wound healing. We established a mouse model to the study delayed wound healing during sepsis distant to the septic focus point. For this reason cecal ligation and puncture (CLP) was combined with the creation of a superficial wound on the mouse ear. Control animals received the same procedure without CPL. Epithelialization was measured every second day by direct microscopic visualization up to complete closure of the wound. As interplay of TNF-α, TGF-β, matrix metalloproteinases (MMP), and tissue inhibitors of metalloproteinases (TIMP) is important in wound healing in general, TNF-α, TGF-β, MMP7, and TIMP1 were assessed immunohistochemical in samples of wounded ears harvested on days 2, 6, 10 and 16 after wounding. After induction of sepsis, animals showed a significant delay in wound epithelialization from day 2 to 12 compared to control animals. Complete wound healing was attained after mean 12.2± standard deviation (SD) 3.0 days in septic animals compared to 8.7± SD 1.7 days in the control group. Septic animals showed a significant reduction in local pro-inflammatory cytokine level of TNF-α on day 2 and day 6 as well as a reduced expression of TGF-β on day 2 in wounds. A significant lower expression of MMP7 as well as TIMP1 was also observed on day 2 after wounding. The induction of sepsis impairs wound healing distant to the septic focus point. We could demonstrate that expression of important cytokines for wound repair is deregulated after induction of sepsis. Thus restoring normal cytokine response locally in wounds could be a good strategy to enhance wound repair in sepsis

One More Notch Towards the Connection of ECM and Cell Communication

Cellular membrane molecules have numerous functions on the cell such as controlling migration, adhesion, or cell to cell communication. Integrins are a transmembrane, cell receptor protein that dimerize to facilitate cell-extracellular matrix adhesion. The cell receptor Notch works to allow cell to cell communication through ligand binding. There is some evidence to support a conspiring relationship between Notch and integrins through some unknown factor, but little data showing how. To address this issue, we blocked integrin function by incubating endothelial cells with β1 and β3 integrin antibodies. Expression of Notch related genes were then examined through real-time PCR. Several genes showed a change in expression with integrin inhibition. Notably, the expression pattern of some of these genes show a reversal when Notch is inhibited, demonstrating a Notch-dependent effect. β-catenin is one of the genes that showed this dynamic expression profile, and through prior experiments has been shown to contribute in Notch regulation. These results are significant in the fact that integrins may have an impact on Notch signaling

Beyond the Matrix: The Many Non-ECM Ligands for Integrins

The traditional view of integrins portrays these highly conserved cell surface receptors as mediators of cellular attachment to the extracellular matrix (ECM), and to a lesser degree, as coordinators of leukocyte adhesion to the endothelium. These canonical activities are indispensable; however, there is also a wide variety of integrin functions mediated by non-ECM ligands that transcend the traditional roles of integrins. Some of these unorthodox roles involve cell-cell interactions and are engaged to support immune functions such as leukocyte transmigration, recognition of opsonization factors, and stimulation of neutrophil extracellular traps. Other cell-cell interactions mediated by integrins include hematopoietic stem cell and tumor cell homing to target tissues. Integrins also serve as cell-surface receptors for various growth factors, hormones, and small molecules. Interestingly, integrins have also been exploited by a wide variety of organisms including viruses and bacteria to support infectious activities such as cellular adhesion and/or cellular internalization. Additionally, the disruption of integrin function through the use of soluble integrin ligands is a common strategy adopted by several parasites in order to inhibit blood clotting during hematophagy, or by venomous snakes to kill prey. In this review, we strive to go beyond the matrix and summarize non-ECM ligands that interact with integrins in order to highlight these non-traditional functions of integrins

The Incidence of Chromosomal Aberrations in Prenatally Diagnosed Isolated Agenesis of the Corpus Callosum

Purpose To establish the prevalence of chromosomal aberrations in fetuses with an apparently isolated agenesis of the corpus callosum (ACC) on prenatal ultrasound. Materials & Methods This was a retrospective study of complete isolated ACC at the time of ultrasound evaluation with respect to karyotype information. Within this group, a subgroup with non-malformation minor abnormalities, such as a single umbilical artery (SUA), polyhydramnios or fetal growth restriction (FGR), was investigated. Results Complete ACC was diagnosed in 343 cases. Of them, 143 (41.6 %) were isolated, with 16 fetuses showing additional minor findings. In 76.2 % (109/143) karyotyping was performed. Additional array CGH analysis was performed in 7.7 % (11/143). Chromosomal aberrations were found in 4.6 % (5/109) overall, in 3.1 % (3/98) of those without any additional sonographic findings (all represented mosaic trisomy 8) and in 18.2 % (2/11) of those with minor abnormalities. The prevalence of pathogenic submicroscopic copy number variant (CNV) was 9 % (1/11). Conclusion Fetal karyotyping is recommended in ACC, as trisomy 8 mosaicism should be considered despite otherwise unremarkable ultrasound. The role of novel techniques such as array CGH and its implication has to be explored in prospective studies

Notch: A Multi-Functional Integrating System of Microenvironmental Signals

The Notch signaling cascade is an evolutionarily ancient system that allows cells to interact with their microenvironmental neighbors through direct cell-cell interactions, thereby directing a variety of developmental processes. Recent research is discovering that Notch signaling is also responsive to a broad variety of stimuli beyond cell-cell interactions, including: ECM composition, crosstalk with other signaling systems, shear stress, hypoxia, and hyperglycemia. Given this emerging understanding of Notch responsiveness to microenvironmental conditions, it appears that the classical view of Notch as a mechanism enabling cell-cell interactions, is only a part of a broader function to integrate microenvironmental cues. In this review, we summarize and discuss published data supporting the idea that the full function of Notch signaling is to serve as an integrator of microenvironmental signals thus allowing cells to sense and respond to a multitude of conditions around them

Expression of MMP7 and TIMP1 in wounds.

<p>A. Percentage of MMP7-positive area on days 2, 6, 10 and 16 after wounding. Septic animals show a significant decrease in MMP7 expression on day 2 and 6 compared to control mice. B. Representative pictures of MMP7 staining at the wound margin captured under 100x magnification of sham and CLP animals on day 2, 6, 10 and 16 after staining for MMP7. Wound margin is located on the right side. C. Percentage of TIMP1-positive area on days 2, 6, 10 and 16. TIMP1 was significantly decreased on day 2 after wounding after CLP. In the later phases of wound repair a significant increase of TIMP1 was observed in septic mice compared to control animals. D. Representative pictures of TIMP1 staining at the wound margin captured under 100x magnification of sham and CLP animals on day 2, 6, 10 and 16 after staining for TIMP1. Wound margin is located on the right side. (Data are expressed as box plots of the median <i>n</i> = 8). * p<0,001, ** p<0,01, * p<0,05.</p

Measurement of systemic inflammatory reaction in mice after CLP compared control.

<p>A. Weight of spleen on day of sacrifice. Septic animals show an increase of weight of spleen on day 10 and 16 after induction of sepsis compared to Sham operated animals (Data is shown as mean ± SD, <i>n</i> = 8). B. Serum level of IL-6 on day of sacrifice. Mice that underwent CLP procedure show a significant increase in IL-6 serum level on day 2, 6 and 10 after surgery compared to control animals (Data is shown as mean ± SD, <i>n</i> = 7). C. Serum level of TNF-α. In correlation to IL-6 level in the blood septic mice show also an augmented level of TNF-α on day 6 and 10 after CLP (Data is shown as mean ± SD, <i>n</i> = 7). * p<0,001, ** p<0,01, *** p<0,05.</p

Expression of TNF-α and TGF-β in wounds.

<p>A. Percentage of TNFα-positive area on days 2, 6, 10 and 16 after wounding. Septic animals express significant less TNF-α compared to control animals on day 2 and 6 after wounding. (Data are expressed as box plots of the median, <i>n</i> = 8). B. Representative pictures of TNF-α staining at the wound margin captured under 100x magnification of sham and CLP animals on day 2, 6, 10 and 16 after staining for TNF-α. Wound margin is located on the right side. C. Percentage of TGF-β-positive area in epidermis on days 2, 6, 10 and 16. Mice that underwent CLP procedure show a reduced level of TGF-β on day 2. (Data are expressed as box plots of the median, <i>n</i> = 7). D. Representative pictures of TGF-β staining at the wound margin captured under 100x magnification of sham and CLP animals on day 2, 6, 10 and 16 after staining for TGF-β. Wound margin is located on the right side. ** p<0,01; *** p<0,05.</p

Fibulin-5 interacts with fibrillin-1 molecules and microfibrils

Fibulin-5 plays an important role in elastic fibre formation in vivo. We have investigated the molecular interactions between fibulin-5 and components of fibrillin-rich microfibrils which form a template for elastin. Fibulin-5 interacted in a dose-dependent manner with a fibrillin-1 N-terminal sequence and with tropoelastin, but not with MAGP-1 (microfibril-associated glycoprotein-1) or decorin. Fibulin-5 did not inhibit interactions between fibrillin-1 N- and C-terminal fragments, or fibrillin-1 interactions with tropoelastin. Fibulin-5 may provide a link between tropoelastin and microfibrils in the pericellular space during elastic fibre assembly