Modification of collagen formation using supplemented mesh materials

Background Formation of recurrent inguinal and incisional hernia shows an underlying defect in the wound healing process. Even following mesh repair an altered collagen formation and insufficient mesh integration has been found as main reason for recurrences. Therefore the development of bioactive mesh materials to achieve a local modification of the scar formation to improve patients outcome is advisable. Methods Thirty-six male Wistar rats were used within this study. A Mersilene ? mesh sample was implanted after midline skin incision and subcutaneous preparation. Before implantation mesh samples were incubated for 30 minutes with either one of the following agents: doxycycline, TGF-beta 3, zinc-hydrogeneaspartate, ascorbic acid, hyaluronic acid. Incubation with a physiologic 0.9 % NaCl solution served as control. Seven and 90 days after mesh implantation 3 animals from each group (n = 6) were sacrificed for morphological observations. Collagen quantity and quality was analyzed measuring the collagen/protein as well as the collagen type I/III ratio. Results Following an implantation interval of 90 days supplementation with doxycycline (39.3 ± 7.0 μg/mg) and hyaluronic acid (34.4 ± 5.8 μg/mg) were found to have a significantly increased collagen/protein ratio compared to implantation of the pure Mersilene ? mesh samples (28.3 ± 1.9 μg/mg). Furthermore, an overall increase of the collagen type I/III ratio was found in all groups indicating scar maturation over time. However, no significant differences were found after 7 and 90 days of implantation comparing collagen type I/III ratio of supplemented mesh samples and control group. Conclusions In summary, we found an influence of supplemented mesh materials on collagen deposition. However, the investigated bioactive agents with reported influence on wound healing were not associated with an improved quality in scar formation.     

Identification of the lipid mediator prostaglandin E2 in tissue immune cells of humans infected with the filaria Onchocerca volvulus

Prostaglandins generated by multiple tissue and immune cells exhibit regulatory effects on the vascular and immune systems. Prostaglandin E₂ (PGE₂), in particular, affects innate as well as adaptive immune mechanisms. We identified PGE₂ in host immune cells adjacent to Onchocerca volvulus in subcutaneous onchocercomas and the affected skin. Using immunohistology, PGE₂ was predominantly detected in infiltrating macrophages but also in plasma cells. Consecutive sections revealed concomitant presence of PGE₂ and transforming growth factor-beta (TGF-beta), representing a second immunoregulative mediator in macrophages and plasma cells. TGF-beta was preferentially observed in the infiltrating macrophages in patients with a generalized hyporeactive onchocerciasis and less in patients with the hyperreactive form. The presence of PGE₂ and TGF-beta in adjoining host cells infiltrating in the onchocercoma and dermis may indicate containment of inflammatory responses that could favour survival of the filarial parasite.     

尖锐湿疣组织LTBP-1和TGF-βRⅡ的表达

目的 探讨潜在结合蛋白（LTBP）-1及其Ⅱ型受体（TGF-βRⅡ）与尖锐湿疣发病的相关性。方法 采用实时荧光定量PCR技术和SP免疫组化技术分别检测30例CA皮损及17例正常包皮组织中LTBP和TGF-βRⅡ的mRNA和蛋白的表达。结果 CA皮损中LTBP-1及TGF-βRⅡ的mRNA的表达水平均低于对照组包皮组织（2 -△△Ct ＞ 2）。免疫组化结果显示：LTBP-1和TGF-βRⅡ的染色强度较正常人包皮组织降低，差异有统计学意义（P ＜ 0.01）。 结论 LTBP-1和TGF-βRⅡ的表达下调，可导致TGF-β活化及信号转导通路的异常。     

Neuropilins are multifunctional coreceptors involved in tumor initiation,growth, metastasis and immunity

The neuropilins (Nrps) are multifunctional proteins involved in development, immunity and cancer. Neuropilin-1 (Nrp1), or its homologue neuropilin-2 (Nrp2), are coreceptors that enhance responses to several growth factors (GFs) and other mediators. Nrps are coreceptors for the class 3 semaphorins (SEMA3), involved in axonal guidance, and several members of the vascular endothelial growth factor (VEGF) family. However, recent findings reveal they have a much broader spectrum of activity. They bind transforming growth factor β1 (TGF-β1) and its receptors, hepatocyte growth factor (HGF) and its receptor (cMet), platelet derived growth factor (PDGF) and its receptors, fibroblast growth factors (FGFs), and integrins. Nrps also promote Hedgehog signaling. These ligands and pathways are all relevant to angiogenesis and wound healing. In the immune system, the Nrps are expressed primarily by dendritic cells (DCs) and regulatory T cells (Tregs), and exert mainly inhibitory effects. In cancer, Nrps have been linked to a poor prognosis, which is consistent with their numerous interactions with ligands and receptors that promote tumor progression. We hypothesize that Nrps boost responses by capturing ligands, regulating GF receptor expression, endocytosis and recycling, and possibly also by signaling independently. Importantly, they promote epithelial-mesenchymal transition (EMT), and the survival of cancer stem cells. The recent finding that Nrps bind and internalize cell-penetrating peptides (CPPs) with arginine/lysine-rich C-terminal motifs (C-end rule; e.g., RXXR) is of interest. These CPPs can be coupled to large drugs for cancer therapy. Almost all studies have been preclinical, but findings suggest Nrps are excellent targets for anti-cancer drug development.     

CX3CR1/CX3CL1 axis negatively controls glioma cell invasion and is modulated by transforming growth factor-beta1

The chemokine CX3CL1 is constitutively expressed in the central nervous system by neurons and astrocytes controlling neuronal survival and neurotransmission. In this work, we analyzed the expression and function of the chemokine CX3CL1 and its receptor, CX3CR1, by human glioma cells. We show that both molecules are expressed on the tumor cell plasma membrane and that soluble CX3CL1 accumulates in the culture supernatants, indicating that the chemokine is constitutively released. We found that CX3CR1 is functional, as all the cell lines adhered to immobilized recombinant CX3CL1 and migrated in response to the soluble form of this chemokine. In addition, the blockade of endogenous CX3CL1 function by means of a neutralizing monoclonal antibody markedly delayed tumor cell aggregation and increased their invasiveness. We also show that CX3CL1 expression is potently modulated by the transforming growth factor-beta1 (TGF-beta1), a key regulator of glioma cell invasiveness. Indeed, both the treatment of glioma cells with recombinant TGF-beta1 and the inhibition of its endogenous expression by siRNA showed that TGF-beta1 decreases CX3CL1 mRNA and protein expression. Overall, our results indicate that endogenously expressed CX3CL1 negatively regulates glioma invasion likely by promoting tumor cell aggregation, and that TGF-beta1 inhibition of CX3CL1 expression might contribute to glioma cell invasive properties.     

Polymorphisms of TGF-beta1 in cystic fibrosis patients

There is a significant phenotypic variance among cystic fibrosis (CF) patients. Due to the role of TGF-beta1 in fibrotic processes we investigated its role in CF pathogenesis. TGF-beta 1 codons 10 and 25 were genotyped in 118 Czech CF patients and 268 controls by PCR-ARMS. Difference between CF and controls was found at codon 10, lower frequency of T/T homozygotes, and codon 25, higher frequency of G/C heterozygotes. We did not prove the association of TGF-beta1 polymorphisms and lung function in CF, however, the TT (codon 10)/GG (codon 25) genotype was preferentially associated with CF-related liver disease and diabetes. Independent of the TGF-beta1 genotype, production of cytokine was higher in patients than in controls with the notable exception of very low levels in Burkholderia cepacia complex colonized patients. In CF, both extremes, highest or lowest TGF-beta 1 production, were associated with impaired lung function.     

Regulating immunity to malaria

The optimal outcome of a malaria infection is that parasitized cells are killed and degraded without inducing significant pathology. Since much of the pathology of malaria infection can be immune-mediated, this implies that immune responses have to be carefully regulated. The mechanisms by which anti-malarial immune responses are believed to be regulated were discussed at the recent Malaria Immunology Workshop (Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA; February 2005). Potential regulatory mechanisms include regulatory T cells, which have been shown to significantly modify cellular immune responses to various protozoan infections, including leishmania and malaria; neutralising antibodies to pro-inflammatory malarial toxins such as glycosylphosphatidylinositol and haemozoin; and self-regulating networks of effector molecules. Innate and adaptive immune responses are further moderated by the broader immunological environment, which is influenced by both the genetic background of the host and by co-infection with other pathogens. A detailed understanding of the interplay between these different immunoregulatory processes may facilitate the rationale design of vaccines and novel therapeutics.