Tissue markers may predict treatment response to antitumor necrosis factor-α agents in children with Crohn's disease

OBJECTIVES

Patients with moderate-severe Crohn's disease (CD) who are treated with antitumor necrosis factor alpha (TNF-α) agents may be subjected to primary nonresponse or partial response. We aimed to identify tissue markers that may predict response to these agents.

METHODS

Pediatric patients (6-18 years) with either ileal or ileo-colonic CD who were treated with anti-TNF-α were stratified into three different groups based on their overall response to therapy at the end of induction including clinical and laboratory parameters (group 1-full responders [FR], group 2-partial responders [PR], group 3-nonresponders [NR]). Seven tissue markers (fibronectin, interleukin [IL]-23R, IL-23, TNF-α, collagen-III, IL-13R, and hypoxia-inducible factors [HIF]-1α) were evaluated. Immunofluorescence (IF) analyses were performed on biopsies from the terminal ileum, which were retrieved up to 6 months before treatment initiation.

RESULTS

Twenty-six CD patients (16 [61.5%] males; age 13.9 ± 2.9 years), including 8 (30.8%) with ileal disease and 18 (69.2%) with ileo-colonic disease, were enrolled. Terminal ileum biopsies from nine patients from group 1, nine from group 2, and eight from group 3 were evaluated. Three antibodies were found to be significantly different between NR and FR groups; Collagen III and fibronectin stains were significantly more prominent in NR patients, while TNF-α stain was significantly more pronounced in FR, p < 0.05 for each. PR could not have been predicted with neither of markers.

CONCLUSIONS

Decreased tissue IF intensity of fibronectin and collagen III and increased intensity of TNF-α may predict response to anti-TNF-α treatment.

Alantolactone Attenuates Renal Fibrosis via Inhibition of Transforming Growth Factor β/Smad3 Signaling Pathway

BACKGRUOUND

Renal fibrosis is characterized by the accumulation of extracellular matrix proteins and interstitial fibrosis. Alantolactone is known to exert anticancer, anti-inflammatory, antimicrobial and antifungal effects; however, its effects on renal fibrosis remains unknown. Here, we investigated whether alantolactone attenuates renal fibrosis in mice unilateral ureteral obstruction (UUO) and evaluated the effect of alantolactone on transforming growth factor (TGF) signaling pathway in renal cells.

METHODS

To evaluate the therapeutic effect of alantolactone, cell counting kit-8 (CCK-8) assay, histological staining, Western blot analysis, and real-time quantitative polymerase chain reaction were performed in UUO kidneys in vivo and in TGF-β-treated renal cells in vitro.

RESULTS

Alantolactone (0.25 to 4 µM) did not affect the viability of renal cells. Mice orally administered 5 mg/kg of alantolactone daily for 15 days did not show mortality or liver toxicity. Alantolactone decreased UUO-induced blood urea nitrogen and serum creatinine levels. In addition, it significantly alleviated renal tubulointerstitial damage and fibrosis and decreased collagen type I, fibronectin, and α-smooth muscle actin (α-SMA) expression in UUO kidneys. In NRK-49F cells, alantolactone inhibited TGF-βstimulated expression of fibronectin, collagen type I, plasminogen activator inhibitor-1 (PAI-1), and α-SMA. In HK-2 cells, alantolactone inhibited TGF-β-stimulated expression of collagen type I and PAI-1. Alantolactone inhibited UUO-induced phosphorylation of Smad3 in UUO kidneys. In addition, it not only decreased TGF-β secretion but also Smad3 phosphorylation and translocation to nucleus in both kidney cell lines.

CONCLUSION

Alantolactone improves renal fibrosis by inhibiting the TGF-β/Smad3 signaling pathway in obstructive nephropathy. Thus, alantolactone is a potential therapeutic agent for chronic kidney disease.

Predictors of Kidney Function Outcomes and Their Relation to SGLT2 Inhibitor Dapagliflozin in Patients with Type 2 Diabetes Mellitus Who Had Chronic Heart Failure

INTRODUCTION

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have a favorable impact on the kidney function in patients with heart failure (HF), while there is no clear evidence of what factors predict this effect. The aim of the study was to identify plausible predictors for kidney function outcome among patients with HF and investigate their association with SGLT2i.

METHODS

We prospectively enrolled 480 patients with type 2 diabetes mellitus (T2DM) treated with diet and metformin and concomitant chronic HF and followed them for 52 weeks. In the study, we determined kidney outcome as a composite of ≥ 40% reduced estimated glomerular filtration rate from baseline, newly diagnosed end-stage kidney disease or kidney replacement therapy. The relevant medical information and measurement of the biomarkers (N-terminal natriuretic pro-peptide, irisin, apelin, adropin, C-reactive protein, tumor necrosis factor-alpha) were collected at baseline and at the end of the study.

RESULTS

The composite kidney outcome was detected in 88 (18.3%) patients of the entire population. All patients received guideline-recommended optimal therapy, which was adjusted to phenotype/severity of HF, cardiovascular risk and comorbidity profiles, and fasting glycemia. Levels of irisin, adropin and apelin significantly increased in patients without clinical endpoint, whereas in those with composite endpoint the biomarker levels exhibited a decrease with borderline statistical significance (p = 0.05). We noticed that irisin ≤ 4.50 ng/ml at baseline and a ≤ 15% increase in irisin serum levels added more valuable predictive information than the reference variable. However, the combination of irisin ≤ 4.50 ng/ml at baseline and ≤ 15% increase in irisin serum levels (area under curve = 0.91; 95% confidence interval = 0.87-0.95) improved the discriminative value of each biomarker alone.

CONCLUSION

We suggest that low levels of irisin and its inadequate increase during administration of SGLT2i are promising predictors for unfavorable kidney outcome among patients with T2DM and concomitant HF.

In Vitro and In Vivo Evidence towards Fibronectin's Protective Effects against Prion Infection

A distinctive signature of the prion diseases is the accumulation of the pathogenic isoform of the prion protein, PrPSc, in the central nervous system of prion-affected humans and animals. PrPSc is also found in peripheral tissues, raising concerns about the potential transmission of pathogenic prions through human food supplies and posing a significant risk to public health. Although muscle tissues are considered to contain levels of low prion infectivity, it has been shown that myotubes in culture efficiently propagate PrPSc. Given the high consumption of muscle tissue, it is important to understand what factors could influence the establishment of a prion infection in muscle tissue. Here we used in vitro myotube cultures, differentiated from the C2C12 myoblast cell line (dC2C12), to identify factors affecting prion replication. A range of experimental conditions revealed that PrPSc is tightly associated with proteins found in the systemic extracellular matrix, mostly fibronectin (FN). The interaction of PrPSc with FN decreased prion infectivity, as determined by standard scrapie cell assay. Interestingly, the prion-resistant reserve cells in dC2C12 cultures displayed a FN-rich extracellular matrix while the prion-susceptible myotubes expressed FN at a low level. In agreement with the in vitro results, immunohistopathological analyses of tissues from sheep infected with natural scrapie demonstrated a prion susceptibility phenotype linked to an extracellular matrix with undetectable levels of FN. Conversely, PrPSc deposits were not observed in tissues expressing FN. These data indicate that extracellular FN may act as a natural barrier against prion replication and that the extracellular matrix composition may be a crucial feature determining prion tropism in different tissues.

Antidepressant Effect of Intermittent Long-Term Systemic Administration of Irisin in Mice

Depression is a psychiatric disorder increasingly diffused worldwide. Evidence suggests that irisin, a myokine secreted by contracting muscle, mediates beneficial effects on several targets, including the brain. Here, the potential antidepressant properties of long-term intermittent systemic irisin administration (100 µg/kg/weekly for 1 month) were evaluated in mice by the Tail Suspension Test (TST), Forced Swim Test (FST), and Open Field Test (OFT). Furthermore, to deepen the molecular pathways underlying irisin treatment, the expression of irisin precursor, neurotrophic/growth factors, and cytokines was analyzed. Irisin treatment significantly decreased the immobility time in the TST and FST, suggesting an antidepressant effect. Additionally, irisin seemed to display an anxiolytic-like effect increasing the time spent in the OFT arena center. These findings were probably due to the modulation of endogenous brain factors as the gene expression of some neurotrophins, such as brain-derived neurotrophic factor (BDNF) and insulin-like growth factor (IGF-1), was upregulated only in irisin-treated mouse brain. Moreover, irisin modulated the expression of some cytokines (IL-1β, IL-4, IL-6, and IL-10). To the best of our knowledge, this is the first study demonstrating that the irisin antidepressant effect may be observed even with a systemic administration in mice. This could pave the way toward intriguing preclinical research in humans.

Cascade Drug Delivery through Tumor Barriers of Pancreatic Cancer via Ultrasound in Combination with Functional Microbubbles

The abundant desmoplastic stroma and the lack of sufficient targets on pancreatic cancer cells render poor drug penetration and cellular uptake, which significantly compromise the chemotherapy efficacy. Herein, we reported a three-step cascade delivery strategy for selective delivery of paclitaxel (PTX) to achieve a targeted therapy for pancreatic cancer. cRGD and cCLT1 peptides, which could target the integrin and fibronectin, respectively, overexpressed in pancreatic cancer cells and stroma, were decorated on PTX-loaded microbubbles, resulting in the formation of dual-targeting PTX-RCMBs. In this strategy, ultrasound in combination with PTX-RCMBs first enhanced the permeability of tumor vessels via cavitation effects and simultaneously helped the generated PTX-RCNPs penetrate into the stroma. Then, the cCLT1 peptide modified on PTX-RCNPs selectively bound the fibronectin highly expressed in the stroma and later targeted the integrin (α5β1) on the cell surface. Finally, another targeting cRGD peptide modified on PTX-RCNPs would further promote PTX uptake via targeting the integrin (αvβ3) on the cell surface. This strategy significantly increased the delivery of PTX into tumor tissues. Moreover, the in vivo effective accumulation of PTX was monitored by ultrasound and fluorescence bimodal imaging. The tumor growth inhibition was investigated on subcutaneous tumor mouse models with 89.8% growth inhibition rate during 21 days of treatment, showing great potential for improving pancreatic cancer therapy.

Fibronectin plays a major role in hypoxia-induced lenvatinib resistance in hepatocellular carcinoma PLC/PRF/5 cells

Resistance to lenvatinib mesylate (LEN), a systemic chemotherapy that can be administered orally, has been a major issue for treatment of hepatocellular carcinoma (HCC). Although HCC is the tumor that most exhibits intratumoral hypoxia, which has been shown to be involved in the development of treatment resistance, there are no reports of LEN resistance in HCC treatment under hypoxia. The purpose of our study was to elucidate the mechanism of treatment resistance to LEN under hypoxia using HCC cell lines. We confirmed LEN resistance under hypoxic conditions in HCC cell lines. There was a significant increase in the IC₅₀ value of PLC/PRF/5 cells from 13.0±0.8 μM in normoxia to 21.3±1.1 μM in hypoxia, but in HepG2 cells, the increase was not significant. To elucidate the LEN resistance mechanism of PLC/PRF/5 cells under hypoxia, we performed microarray analysis and extracted genes that are thought to be related to this mechanism. Furthermore, in-silico analysis confirmed significant changes in the extracellular matrix, and among them, FN1 encoding fibronectin was determined as the hub of the gene cluster. The expression of fibronectin in PLC/PRF/5 cells examined with immunofluorescence staining was significantly elevated in and outside of cells under hypoxia, and tended to decrease when cells were exposed to LEN under normoxia. Furthermore, the fibronectin concentration in the culture solution of PLC/PRF/5 cells examined by ELISA was 2.3 times higher under hypoxia than under normoxia under LEN(-) conditions, and 1.6 times higher under hypoxia than under normoxia under LEN(+) conditions. It is assumed that in PLC/PRF/5 cells, fibronectin is probably suppressed as an indirect effect of LEN under normoxia, but transcription factors such as HIF-1α are induced under hypoxia, thus enhancing the production of fibronectin and attenuating the effect of LEN, resulting in drug resistance. This behavior of fibronectin with LEN exposure under hypoxia is probably specific to PLC/PRF/5 cells. Further studies should verify the combined effective inhibition of fibronectin and the MAPK pathway as a promising therapeutic strategy to enhance the value of LEN in HCC treatment.

MAP/Microtubule Affinity Regulating Kinase 4 Inhibitory Potential of Irisin: A New Therapeutic Strategy to Combat Cancer and Alzheimer's Disease

Irisin is a clinically significant protein playing a valuable role in regulating various diseases. Irisin attenuates synaptic and memory dysfunction, highlighting its importance in Alzheimer's disease. On the other hand, Microtubule Affinity Regulating Kinase 4 (MARK4) is associated with various cancer types, uncontrolled neuronal migrations, and disrupted microtubule dynamics. In addition, MARK4 has been explored as a potential drug target for cancer and Alzheimer's disease therapy. Here, we studied the binding and subsequent inhibition of MARK4 by irisin. Irisin binds to MARK4 with an admirable affinity (K = 0.8 × 107 M-1), subsequently inhibiting its activity (IC50 = 2.71 µm). In vitro studies were further validated by docking and simulations. Molecular docking revealed several hydrogen bonds between irisin and MARK4, including critical residues, Lys38, Val40, and Ser134. Furthermore, the molecular dynamic simulation showed that the binding of irisin resulted in enhanced stability of MARK4. This study provides a rationale to use irisin as a therapeutic agent to treat MARK4-associated diseases.

Involvement of Integrin-Activating Peptides Derived from Tenascin-C in Cancer Aggression and New Anticancer Strategy Using the Fibronectin-Derived Integrin-Inactivating Peptide

Matricellular proteins, which exist in association with the extracellular matrix (ECM) and ECM protein molecules, harbor functional sites within their molecular structures. These functional sites are released through proteolytic cleavage by inflammatory proteinases, such as matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS), and the peptides containing these functional sites have unique biological activities that are often not detected in the parent molecules. We previously showed that tenascin-C (TNC) and plasma fibronectin (pFN), examples of matricellular proteins, have cryptic bioactive sites that have opposite effects on cell adhesion to the ECM. A peptide containing the bioactive site of TNC, termed TNIIIA2, which is highly released at sites of inflammation and in the tumor microenvironment (TME), has the ability to potently and persistently activate β1-integrins. In the opposite manner, the peptide FNIII14 containing the bioactive site of pFN has the ability to inactivate β1-integrins. This review highlights that peptide TNIIIA2 can act as a procancer factor and peptide FNIII14 can act as an anticancer agent, based on the regulation on β1-integrin activation. Notably, the detrimental effects of TNIIIA2 can be inhibited by FNIII14. These findings open the possibility for new therapeutic strategies based on the inactivation of β1-integrin by FNIII14.

A dual-functional Embolization-Visualization System for Fluorescence image-guided Tumor Resection

Rationale: Intraoperative bleeding impairs physicians' ability to visualize the surgical field, leading to increased risk of surgical complications and reduced outcomes. Bleeding is particularly challenging during endoscopic-assisted surgical resection of hypervascular tumors in the head and neck. A tool that controls bleeding while marking tumor margins has the potential to improve gross tumor resection, reduce surgical morbidity, decrease blood loss, shorten procedure time, prevent damage to surrounding tissues, and limit postoperative pain. Herein, we develop and characterize a new system that combines pre-surgical embolization with improved visualization for endoscopic fluorescence image-guided tumor resection. Methods: Silk-elastinlike protein (SELP) polymers were employed as liquid embolic vehicles for delivery of a clinically used near-infrared dye, indocyanine green (ICG). The biophysical properties of SELP, including gelation kinetics, modulus of elasticity, and viscosity, in response to ICG incorporation using rheology, were characterized. ICG release from embolic SELP was modeled in tissue phantoms and via fluorescence imaging. The embolic capability of the SELP-ICG system was then tested in a microfluidic model of tumor vasculature. Lastly, the cytotoxicity of the SELP-ICG system in L-929 fibroblasts and human umbilical vein endothelial cells (HUVEC) was assessed. Results: ICG incorporation into SELP accelerated gelation and increased its modulus of elasticity. The SELP embolic system released 83 ± 8% of the total ICG within 24 hours, matching clinical practice for pre-surgical embolization procedures. Adding ICG to SELP did not reduce injectability, but did improve the gelation kinetics. After simulated embolization, ICG released from SELP in tissue phantoms diffused a sufficient distance to deliver dye throughout a tumor. ICG-loaded SELP was injectable through a clinical 2.3 Fr microcatheter and demonstrated deep penetration into 50-µm microfluidic-simulated blood vessels with durable occlusion. Incorporation of ICG into SELP improved biocompatibility with HUVECs, but had no effect on L-929 cell viability. Principle Conclusions: We report the development and characterization of a new, dual-functional embolization-visualization system for improving fluorescence-imaged endoscopic surgical resection of hypervascular tumors.

Fetal fibronectin testing for reducing the risk of preterm birth

BACKGROUND

Fetal fibronectin (FFN) is an extracellular matrix glycoprotein localized at the maternal-fetal interface of the amniotic membranes, between chorion and decidua, where it is concentrated in this area between decidua and trophoblast. In normal conditions, FFN is found at very low levels in cervicovaginal secretions. Levels greater than or equal to 50 ng/mL at or after 22 weeks have been associated with an increased risk of spontaneous preterm birth. In fact, FFN is one of the best predictors of preterm birth in all populations studied so far, and can help in selecting which women are at significant risk for preterm birth. This is an update of a review first published in 2008.

OBJECTIVES

To assess the effectiveness of management based on knowledge of FFN testing results for preventing preterm birth.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register (7 September 2018), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (7 September 2018), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomized controlled trials of pregnant women screened with FFN for risk of preterm birth. Studies included are based exclusively on knowledge of FFN results versus no such knowledge, and we have excluded studies including women with only positive or only negative FFN results.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data, and checked them for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We identified 16 trials, of which six were eligible for inclusion. The six included studies randomized 546 women with singleton gestations and threatened preterm labor (PTL) at 23 0/7 to 34 6/7 weeks. A total of 277 women were randomized to knowledge and 269 to no knowledge of FFN. No trials were identified on asymptomatic women or multiple gestations.The risk of bias of included studies was mixed. For selected important outcomes, preterm birth before 37, 34, and 32 weeks, and maternal hospitalization, we graded the quality of the evidence and created a 'Summary of findings' table. For these outcomes, the evidence was graded as mainly low quality due to the imprecision of effect estimates.Management based on knowledge of FFN results may reduce preterm birth before 37 weeks (21.6%) versus controls without such knowledge (29.2%) (risk ratio (RR) 0.72, 95% confidence interval (CI) 0.52 to 1.01; 4 trials; 357 women; low-quality evidence). However, management based on knowledge of FFN results may make little or no difference to preterm birth before 34 (RR 1.09, 95% CI 0.54 to 2.18; 4 trials; 357 women; low-quality evidence) or maternal hospitalization (RR 1.06, 95% CI 0.79 to 1.43; 5 trials; 441 women; low-quality evidence). The evidence for preterm birth before 32 weeks is uncertain because the quality was found to be very low (average RR 0.79, 95% CI 0.16 to 3.96; 4 trials; 357 women; very low-quality evidence).For all other outcomes, for which there were available data (preterm birth less than 28 weeks; gestational age at delivery (weeks); birthweight less than 2500 g; perinatal death; tocolysis; steroids for fetal lung maturity; time to evaluate; respiratory distress syndrome; neonatal intensive care unit (NICU) admission; and NICU days), knowledge of FFN results may make little or no difference to the outcomes.

AUTHORS' CONCLUSIONS

The evidence from this review suggests that management based on knowledge of FFN results may reduce preterm birth before 37 weeks. However, our confidence in this result is limited as the evidence was found to be of low quality. Effects on other substantive outcomes are uncertain due to serious concerns in study design, inconsistency, and imprecision of effect estimates. No trials were identified on asymptomatic women, or multiple gestations.Future studies are needed that include specific populations (e.g. singleton gestations with symptoms of preterm labor), a study group managed with a protocol based on the FFN results, and that report not only maternal but also important perinatal outcomes. Cost-effectiveness analyses are also needed.

Synthetic α5β1 integrin ligand PHSRN is proangiogenic and neuroprotective in cerebral ischemic stroke

Ischemic stroke is the leading cause of disability and death worldwide. An effective therapeutic approach is urgently needed. Stroke-induced angiogenesis and neurogenesis are essential mechanisms in the long-term repair. Extracellular matrix proteins are also involved in tissue self-repair. Recently, a PHSRN (Pro-His-Ser-Arg-Asn) peptide from the fibronectin synergistic motif that can promote wound healing in epithelia and induce endothelial proliferation and cancer cell migration was identified. The therapeutic potential of this peptide in stroke is unknown. Here, we examined the potential of PHSRN in stroke therapy using an ischemic rat model of middle cerebral artery occlusion (MCAO). PHSRN reduced the infarct volume in MCAO rats, improved neurological function, and alleviated motor function impairment. PHSRN targeted the damaged brain region and distributed to endothelial cells after intraperitoneal injection. PHSRN significantly promoted angiogenesis and vascular endothelial growth factor secretion through activation of integrin α5β1 and its downstream intracellular signals, e.g., focal adhesion kinase, Ras, cRaf, and extracellular-signal-regulated kinase. PHSRN treatment also stimulated neurogenesis in MCAO rats, and maintained neuronal survival and neuronal morphologic complexity via induction of VEGF secretion. Together, these results provide insights into the role of integrin α5β1 following ischemia and support the feasibility of using PHSRN peptide in stroke therapy.

High irisin levels are associated with better glycemic control and bone health in children with Type 1 diabetes

AIM

Irisin is a new peptide produced mainly by the skeletal muscle playing an important role both in glucose/energy homeostasis and bone metabolism. Childhood type 1 diabetes mellitus (T1DM) is associated with decreased bone mass. We aimed to evaluate irisin levels in TD1M children and their correlation with bone metabolism and glycaemic control.

METHODS

Ninety-six T1DM subjects (12.2 ± 4 years), 56 on multiple daily injections (MDI), 40 on continuous subcutaneous insulin infusion (CSII), and 34 controls were included in the study. Irisin and bone remodeling markers were quantified in sera from patients and controls. Bone mineral density (BMD) was evaluated by QUS.

RESULTS

Increased irisin levels were found in T1DM patients respect to controls (p < 0.001). With adjustment for age, irisin levels significantly correlated negatively with HbA1c% (r = -0.105, p < 0.001), years of diabetes (r = -0.07, p < 0.04), 25(OH)-Vitamin D (r = -0.175, p < 0.0001), and positively with BTT-Z-score (r = 0.088, p = 0.016), and osteocalcin (r = 0.059, p < 0.04). We detected the highest levels of irisin in CSII patients compared to MDI and controls (p < 0.001 and p < 0.007 respectively).

CONCLUSIONS

We demonstrated high irisin levels in T1DM children and the association of highest irisin amounts to a better glycaemic control and bone health in TDM1 subjects on CSII.

Potency-matched Dual Cytokine-Antibody Fusion Proteins for Cancer Therapy

A novel biopharmaceutical, consisting of the F8 mAb (specific to a splice isoform of fibronectin) simultaneously fused to both TNF and IL2, was found to react with the majority of solid tumors and hematologic malignancies in mouse and man, but not with healthy adult tissues. The product selectively localized to neoplastic lesions in vivo, as evidenced by quantitative biodistribution studies using radioiodinated protein preparations. When the potency of the cytokine payloads was matched by a single-point mutation, the resulting fusion protein (IL2-F8-TNFmut) eradicated soft-tissue sarcomas in immunocompetent mice, which did not respond to individual antibody-cytokine fusion proteins or by standard doxorubicin treatment. Durable complete responses were also observed in mice bearing CT26, C1498, and F9 tumors. The simultaneous delivery of multiple proinflammatory payloads to the cancer site conferred protective immunity against subsequent tumor challenges. A fully human homolog of IL2-F8-TNFmut, which retained selectivity similar to its murine counterpart when tested on human material, may open new clinical applications for the immunotherapy of cancer. Mol Cancer Ther; 16(11); 2442-51. ©2017 AACR.

Material-driven fibronectin assembly for high-efficiency presentation of growth factors

Growth factors (GFs) are powerful signaling molecules with the potential to drive regenerative strategies, including bone repair and vascularization. However, GFs are typically delivered in soluble format at supraphysiological doses because of rapid clearance and limited therapeutic impact. These high doses have serious side effects and are expensive. Although it is well established that GF interactions with extracellular matrix proteins such as fibronectin control GF presentation and activity, a translation-ready approach to unlocking GF potential has not been realized. We demonstrate a simple, robust, and controlled material-based approach to enhance the activity of GFs during tissue healing. The underlying mechanism is based on spontaneous fibrillar organization of fibronectin driven by adsorption onto the polymer poly(ethyl acrylate). Fibrillar fibronectin on this polymer, but not a globular conformation obtained on control polymers, promotes synergistic presentation of integrin-binding sites and bound bone morphogenetic protein 2 (BMP-2), which enhances mesenchymal stem cell osteogenesis in vitro and drives full regeneration of a nonhealing bone defect in vivo at low GF concentrations. This simple and translatable technology could unlock the full regenerative potential of GF therapies while improving safety and cost-effectiveness.

Biointerface: protein enhanced stem cells binding to implant surface

The number of metallic implantable devices placed every year is estimated at 3.7 million. This number has been steadily increasing over last decades at a rate of around 8 %. In spite of the many successes of the devices the implantation of biomaterial into tissues almost universally leads to the development of an avascular sac, which consists of fibrous tissue around the device and walls off the implant from the body. This reaction can be detrimental to the function of implant, reduces its lifetime, and necessitates repeated surgery. Clearly, to reduce the number of revision surgeries and improve long-term implant function it is necessary to enhance device integration by modulating cell adhesion and function. In this paper we have demonstrated that it is possible to enhance stem cell attachment using engineered biointerfaces. To create this functional interface, samples were coated with polymer (as a precursor) and then ion implanted to create a reactive interface that aids the binding of biomolecules--fibronectin. Both AFM and XPS analyses confirmed the presence of protein layers on the samples. The amount of protein was significant greater for the ion implanted surfaces and was not disrupted upon washing with detergent, hence the formation of strong bonds with the interface was confirmed. While, for non ion implanted surfaces, a decrease of protein was observed after washing with detergent. Finally, the number of stem cells attached to the surface was enhanced for ion implanted surfaces. The studies presented confirm that the developed bionterface with immobilised fibronectin is an effective means to modulate stem cell attachment.

Adnectins: engineered target-binding protein therapeutics

Adnectins™ are a new family of therapeutic proteins based on the 10th fibronectin type III domain, and designed to bind with high affinity and specificity to therapeutically relevant targets. Adnectins share with antibody variable domains a beta-sheet sandwich fold with diversified loops, but differ from antibodies in primary sequence and have a simpler, single-domain structure without disulfide bonds. As a consequence, Adnectins bind targets with affinity and specificity as high as those of antibodies, but are easier to manipulate genetically and compatible with bacterial expression systems. Adnectins that bind macromolecular targets with nanomolar and picomolar affinity have been selected using in vitro evolution methods, including mRNA display, phage display and yeast display. CT-322, a PEGylated, anti-angiogenic Adnectin that binds vascular endothelial growth factor (VEGF) receptor 2 and blocks its interaction with VEGF A, C and D, is being evaluated in Phase II clinical trials for efficacy in several oncology indications.

Role of substrates in diabetes therapy: stem cell differentiation and islet transplantation

Type 1 diabetes affects more than a million people in the United States and many more across the world. While pharmaceutical interventions and insulin supplementation are the most commonplace treatment of diabetes, these are not essentially cures and can potentially lead to long-term complications. Transplantation of insulin-producing Islets of Langerhans from donor pancreas has been established as a promising alternative to diabetes therapy. While successful islet transplantation has the potential of providing a cure, the primary hurdles to be overcome for it to be clinically viable are the scarcity of donor islets and immune rejection of transplanted islets. Recent advances in stem cell culture and differentiation techniques have established stem cells as a likely source of transplantable islets. Different stem cell sources have been induced toward pancreatic differentiation using specific chemical perturbations along with use of specific substrates. An approach to overcoming the second hurdle of immune rejection of transplantable islets is to encapsulate the islets in specific biomaterials. In this review, we discuss the extensive use of various substrates for pancreatic differentiation of different stem cell sources, along with different biomaterial designs used for islet transplantation.

[Protein scaffolds as alternatives to whole antibodies: from discovery research to clinical development]

Recent advances in combinatorial protein engineering have made it possible to develop non-Ig protein scaffolds that can potentially substitute for most whole antibody-associated properties. These protein scaffolds display most of the binding properties associated with the variable domain of antibodies. In theory, many different natural human protein backbones are suitable to be used as recombinant templates for engineering ; in practice however, only a few have yielded the necessary properties to be translated into << druggable biologicals >>. Amongst these properties, potential broad specificities towards any kind of target, ease of production, small size, good tolerability and low immunogenicity are essential. Intellectual property is another key issue. In this review, a particular emphasis will be given to the most validated non-Ig scaffolds that have reached the clinical development phase.

[Preparation of recombinant polypeptide of N-terminal heparin-binding domain of fibronectin and its effect on disseminated intravascular coagulation in rats]

This study was aimed to prepare the polypeptide of N-terminal heparin-binding domain of fibronectin(rhFNHN-29 polypeptide) with pichia expression system, to detect biological activity of recombinant polypeptide and investigate its effect on disseminated intravascular coagulation (DIC) in rats. The sequence of N-terminal heparin-binding domain of fibronectin was amplified from FNcDNA by PCR. The aim gene was cloned into T vector for selection. Then it was cloned into pAo815SM and pPIC9K vectors.Lined pPIC9K vectors were transformed into GS115 Pichia cells so as to express the aim polypeptide in Pichia expression system. The fermentation liquid were precipitated by 80% ammonium sulfate, and the further dissolved sediment were purified using S-100 column and SP column. Its activity of binding with heparin were detected by Western-blot. The established DIC rats (40 rats) were randomly divided into two groups. One group was treated with rhFNHN-29 polypeptide, and the other was treated with normal saline. The rats in the former group were injected with rhFNHN-29 polypeptide (10 mg/kg) through tail vein at 0.5 hour before, 2 hours and 4 hours after injection of LPS respectively. The rats in latter group were injected with equal volume saline. In addition, 20 normal rats injected with normal saline were as normal controls. 500 microl blood was taken from the rat vein, at 6 hours after the injection of LPS. White blood cell (WBC), hemoglobin (Hb) and platelets were tested from 50 microl blood. The rest 450 microl blood was used to isolate plasma for detecting TNFa level and coagulogram. The rats were killed at 24 hours after injection with LPS. Their livers, lungs, hearts, kidneys, and brain tissues were taken for histopathologic examination. The results showed that the aim polypeptide was successfully expressed in Pichia expression system. The expression level reached approximately 30 mg/L. The polypeptide had activity of binding with heparin antibody. In the experiment study of polypeptide effect on DIC in rats, the plasma TNFa level in polypeptide-treated group was lower than that in saline control group, the hemogram, coagulogram and histopathology were more obviously improved in polypeptide-treated group as compared with saline control group. It is concluded that the rhFNHN-29 polypeptide is successfully prepared, this polypeptide can antagonize DIC induced by endotoxin in rats.

[Recombinant polypeptide of N-terminal heparin-binding domain of fibronectin antagonizes hepatic failure induced by endotoxin in mice]

OBJECTIVE

To study the preventive effect of recombinant polypeptide of N-terminal heparin-binding domain of fibronectin on hepatic failure induced by endotoxin in mice.

METHODS

The 40 hepatic failure Balb/C mice were established by intraperitoneal injection of lipopolysaccharide (LPS) and d-galactosamine (GalN). The mice were randomly divided into two groups, one for polypeptide treatment, the othe for saline treatment.Another 20 mice were used as normal control. Half hour prior to, 1, 2, and 3 hours after injection of LPS and GalN, the rhFNHN-29 polypeptide (10 mg/kg) was injected through the tail vein of mice. The same volume of saline was given to the saline treated group and the normal control group.Six hours after the injection of LPS and GalN, 250 microl blood was taken from the eye vein of each mouse for plasma TNFalpha testing, and 72 hours after the injection, mortality rates of the mice of different groups were observated. The liver, lung, heart, kidney, and brain tissues of the survival mice were examined for histopathology after 72 hours. The Liver tissue was also examined for electron micrograph and for mRNA expression of TNFalpha, IL-1beta, IL-6 by RT-PCR.

RESULTS

The 72 hours mortality rates in saline-treated and polypeptide treated-mice were 70% and 15% respectively (P < 0.01). The histopathology showed that necrosis occurred less on the hepatocytes of polypeptide treated mice than on the saline treated ones. The ultrastructure of hepatocyte under the electron microscope showed that cell apparatus of saline treated mice were destroyed and cytoplasm become loose. The expression level of TNFalpha, IL-1beta, IL-6 mRNA on hepatocytes in polypeptide treated mice was significantly lower (1.26 +/- 0.37, 0.98 +/- 0.21, 0.43 +/- 0.17, 87.43 +/- 16.7 respectively) than that in the saline treated ones (1.98 +/- 0.56, 1.24 +/- 0.35, 0.64 +/- 0.25 and 236.11 +/- 32.7, respectively) (P < 0.01). Similarly, the plasm TNFalpha level (87.43 +/- 16.7) in polypeptide treated group was significantly lower than that (236.11 +/- 32.7) in the saline treated group (P < 0.01).

CONCLUSION

The rhFNHN-29 polypeptide can prevent and treat hepatic failure induced by endotoxin. The mechanism by which the polypeptide takes the effect may involve its ability to down-regulate expression of those inflammation factors such as TNFalpha, IL-1beta, IL-6.

Inhibitory effect of recombinant fibronectin polypeptide CH50 on invasion and metastasis of melanoma B16 cells

In order to investigate the inhibitory effect and mechanism of recombinant polypeptide CH50 on invasion and metastasis of melanoma B16 cells, the recombinant polypeptide CH50 was separated and purified by ion exchange chromatographic technique. The melanoma B16 cells treated with purified CH50 were cultured in vitro, the number was counted at 4, 24, 48 and 72 h and their morphological changes were observed in order to detect their adhesion and spreading abilities. In in vivo study, the melanoma B16 cells were labeled with CFSE and treated with CH50 and then they were injected into mice via mouse-tail veins. After 5 h, the lung tissues were fixed by frozen section. Accumulation and invasion abilities of B16 cells on lung tissues were observed under the fluorescent microscopy. The results showed that the morphological character of B16 cells treated with CH50 changed greatly and the number of B16 cells treated with CH50 decreased significantly (P<0.05). The adhesion and spreading abilities of B16 cells treated with CH50 were weakened obviously and the metastasis foci on lung tissues reduced. It was concluded that the recombinant polypeptide CH50 inhibited invasion and metastasis of melanoma B16 cells on tissues and could be a prospective bio-product in tumor general therapy.

Characterization of non-neuronal elements within fibronectin mats implanted into the damaged adult rat spinal cord

Previous studies have shown that mats made from fibronectin (FN) integrate well into spinal cord lesion sites and support extensive axonal growth. Using immunohistochemistry, we have investigated the non-neuronal factors that contribute to these properties. Extensive vascularization was observed in FN mats by 1 week along with heavy macrophage infiltration by 3 days post-implantation. By 1 week post-implantation, laminin tubules had formed and were associated with axons and p75 immunoreactive Schwann cells. By 4 weeks post-implantation, most axons were associated with Schwann cell derived myelin. Few oligodendrocytes were present within the mat, even with an increase in the number of oligodendrocyte precursors around the implant site by 7 days post-implantation. Astrocyte proliferation also occurred in the intact tissue, with a prominent glial scar forming around the implant within 4 weeks. However, by 2 months post-implantation astrocytes were present in the FN implant site and were intermingled with the axons. Axonal ingrowth and integration of the FN mats is probably due to the ability of FN mats to support and organize infiltration of Schwann cells and deposition of laminin. At later time points, myelinated axons remain in the implant site, even after other elements (e.g. macrophages and laminin) have disappeared. Both of these properties are likely to be important in the design of biomaterial bridges for CNS regeneration.

Experimental usage of hydroxyapatite preadsorption with fibronectin to increase permanent stability and longevity of spinal implants

Hydroxyapatite has been used in orthopaedic and particularly in spinal surgery by precoating implants to indirectly increase osteoblasts' adhesion and subsequently their stability and longevity. Fibronectin preadsorption synergistically with appropriately constructed hydroxyapatite's surface texture to enhance osteoblasts' adhesion has not been, to the authors' knowledge, previously investigated. In osteoporotic spines, methods to increase implant stability (pedicle screws and cages) are of major value.

OBJECTIVE

This experimental study investigated the contribution of fibronectin preadsorption to enhance osteoblasts' adhesion and strength on hydroxyapatite.

METHODS

Hydroxyapatite substrata with two different surface roughnesses (rough HA180 and the smooth HA1200) were produced and human osteoblasts were seeded on them after culture. Prior to osteoblasts seeding, the hydroxyapatite substrata were immersed in fibronectin solution. Osteoblast attachment on each of the two hydroxyapatite substrata was evaluated by recording the number of cells, while the osteoblast's adhesion strength was determined by measuring the shear stress required to detach the cells from the hydroxyapatite substrates.

RESULTS

Fibronectin preadsorption increased the number of attached osteoblasts on smooth and rough hydroxyapatite substratum at 40% and 62% respectively, while it increased osteoblast attachment strength on the smooth and rough substratum at 165% and 73% respectively.

CONCLUSIONS

Fibronectin preadsorption and smooth hydroxyapatite surface texture synergistically increased the adhesion's strength of human osteoblasts "in vitro", while preadsorption and rough hydroxyapatite surface increased the number of attached osteoblasts. Further studies in primates and human beings should be carried out to disclose the clinical relevance of the above mentioned observations in spine surgery.

Synthetic fibronectin peptide exerts neuroprotective effects on transient focal brain ischemia in rats

Leukocytes have been investigated during the past decade for their roles in secondary tissue damage after ischemia/reperfusion injury. Peptide PRARIY, a synthetic fibronectin peptide, has shown an anti-adhesion effect in in vitro studies. Previous studies have demonstrated that anti-adhesion agents lead to reductions in apoptosis. The purpose of the present study was to determine whether the peptide PRARIY displays anti-inflammatory, anti-apoptotic, and neuroprotective effects following transient focal brain ischemia in rats. Twenty-six male Sprague-Dawley rats (300-350 g) were randomly divided into three groups: phosphate-buffered saline (PBS) controls, PRARI controls, and PRARIY treatments. The right middle cerebral artery was transiently occluded using a 4-0 nylon suture. One hour later, the occluder was withdrawn, and reperfusion was maintained for 48 h. Immediately after reperfusion, the peptides (20 mg/kg, dissolved in PBS) and the same volume of PBS were continuously infused through the right external carotid artery using an osmotic minipump for 24 h. Neurological deficits were examined at 3, 24, and 48 h after ischemia. Forty-eight hours after reperfusion, the rats were sacrificed for determining infarction size, leukocyte infiltration, and apoptosis in the ischemia area. Unexpectedly, PRARIY did not influence leukocyte infiltration. However, PRARIY-treated rats showed significantly functional outcome, reduction of infarction size, decrease of TUNEL positive cells, and increase of Bcl-2 (anti-apoptotic protein) positive cells in the ischemic areas when compared to the controls. These data indicate that the peptide PRARIY exerts its neuroprotective effects via supporting neural cell survival rather than anti-leukocyte recruitment following brain ischemia/reperfusion injury.

The role of fibronectin in fibroblast migration during tissue repair

Fibronectin is known to stimulate cell growth and migration, but research does not provide a complete picture of all the mechanisms involved. Further studies are needed before practitioners can apply in vitro results to in vivo environments.

Ocular Surface Findings in Hallopeau-Siemens Subtype of Dystrophic Epidermolysis Bullosa

PURPOSE

This article describes the clinical features and long-term changes in corneal sensitivity, tear function, and impression cytology findings in a patient with recessive dystrophic epidermolysis bullosa (DEB).

METHODS

The patient underwent best-corrected Landolt visual acuity measurements, slit-lamp examinations, anterior segment photography, Schirmer test with anesthesia, tear film break-up time, corneal fluorescein and Rose-Bengal staining, assessment of corneal sensitivity, and conjunctival impression cytology at the initial and final visits.

RESULTS

The patient had a recurrent corneal erosion in the right eye and a painful corneal blister with extensive superficial punctuate keratopathy in the left eye, which remained refractory to treatment with patching, lubricants, and antibiotic ointments for 10 weeks. The corneal disease in both eyes responded swiftly to topical fibronectin, topical nonpreserved tears, vitamin A ointment, and therapeutic soft contact lenses. Maintenance treatment was continued with preservative-free topical tear drops and vitamin A ointment. Corneal disease did not recur in the patient during the follow-up of 29 months. The mean corneal sensitivity and tear film break-up time were decreased initially in both eyes and attained normal values with treatment. Impression cytology revealed squamous metaplasia, loss of cellular cohesion, and total absence of goblet cells before treatment, all of which were observed to be normalized at the final follow-up.

CONCLUSIONS

The ocular surface disease in DEB was characterized by low corneal sensitivity, disorder of tear quality, decreased cellular cohesion, squamous metaplasia of the conjunctiva, and goblet cell loss. Close follow-up for ocular complications in DEB is essential and a pathophysiology-oriented approach to the epithelial disease may not only provide rapid healing but might prevent recurrences as well.

Protective effect of fibronectin for endotoxin-induced liver injury after partial hepatectomy in rats1

BACKGROUND

Endotoxemia may occur after hepatectomy and become the cause of post-operative death. Fibronectins (Fns) are involved in a number of biological processes, such as cellular adhesion, motility, differentiation, apoptosis, hemostasis, wound healing, and ischemic injury. Studies were performed to determine whether Fn influences the survival rate of rats subjected to endotoxin-induced liver injury after partial hepatectomy.

MATERIALS AND METHODS

Lipopolysaccharide (LPS) was administered intravenously to male Sprague-Dawley rats within 48 h of 70% hepatectomy. Before LPS administration, plasma Fn or bovine serum albumin was given intravenously.

RESULTS

The survival rate of the Fn-treated group was markedly improved compared with that of the controls. Fn prevented increases in the concentrations of serum enzymes and total bilirubin related to liver injury. The levels of inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-1beta, and cytokine-induced neutrophil chemoattractant, in serum and liver tissue, also were significantly lower in the Fn-treated group than in the control group. Furthermore, the degree of apoptosis and necrosis in remnant liver was significantly decreased in the Fn-treated rats compared with the controls.

CONCLUSIONS

These results indicate that Fn prevents endotoxin-induced liver injury after partial hepatectomy, at least in part through the inhibition of production of inflammatory cytokines, necrosis and apoptosis in the remaining liver.

Biomimetic approach on human periodontal ligament cells using synthetic oligopeptides

BACKGROUND

Periodontal ligament (PDL) cells, connecting root cementum with alveolar bone, are important for periodontal wound healing. In order to obtain a predictable periodontal regeneration, selective adhesion and proliferation of PDL cells are essential. The purpose of this study was to investigate the effects of synthetic peptides mimicking cell-binding domain of fibronectin (FN) on human PDL cells.

METHODS

Two types of oligopeptides, Gly3-Pro-His-Ser-Arg-Asn-Gly6-Arg-Gly-Asp-Gly (G3PHSRNG6RGDG) and Gly3-His-Pro-Asn-Arg-Ser-Gly6-Arg-Gly-Asp-Gly (G3HPNRSG6RGDG), were constructed using a solid-phase peptide synthesizer. Fibronectin type III ninth to tenth domain (FN III 9-10) and Arg-Gly-Asp-Ser (RGDS) were prepared for comparison with the effects of synthetic peptides. These peptides were coated onto 96-well cell culture plates with 0.001 approximately 100 microM concentrations. Cultured human PDL cells were then applied to the peptide-coated wells at a density of 1 x 10(4)/well. After 1 hour incubation at 37 degrees C, adhered cells were fixed, stained, and examined by phase contrast microscopy for cell spreading assay. Attached PDL cells were solubilized with 2% sodium dodecyl sulfate (SDS) for the cell attachment assay by measuring absorbance at 595 nm in microplate reader. Western blot analysis was performed to determine extracellular signal-regulated kinase (ERK1/2) activity.

RESULTS

Cell attachment and spreading assays revealed that G3PHSRNG6RGDG (> or = 10 microM) possesses similar adhesive behavior to FN III 9-10. G3PHSRNG6RGDG showed a comparable ERK1/2 activity when compared to FN III 9-10.

CONCLUSIONS

G3PHSRNG6RGDG enhanced an attachment and spreading of human PDL cells thereby increasing ERK1/2 activity. Taken together, it is anticipated that this peptide might be a potential tool for arranging a biologically attractive environment for PDL cells, which would enhance periodontal regeneration efficacy.

Fibronectin suppresses apoptosis and protects mice from endotoxic shock

Multiple-organ failure related to septicemia is a common cause of early mortality after liver transplantation. Endotoxemia following living donor hepatectomy may be a cause of postoperative death. Plasma fibronectin (Fn) exerts a broad range of biological effects on cellular adhesion, motility, differentiation, apoptosis, hemostasis, wound healing, reticuloendothelial system function, and ischemic injury. We studied the therapeutic effect of plasma Fn in mice after an intraperitoneal injection of lipopolysaccharide (LPS) and d-galactosamine (GalN). Female Balb/c mice received simultaneous intraperitoneal injection of LPS (50 microg/kg) and GalN (400 mg/kg). Thirty minutes prior to GalN/LPS administration, plasma Fn or bovine serum albumin was given intravenously. A single administration of plasma Fn (500 mg/kg) protected in dose-dependent fashion against lethal shock after GalN/LPS challenge. Plasma Fn significantly reduced the serum tumor necrosis factor-alpha, interferon-gamma, and interleukin-6 levels and significantly increased the serum interleukin-10 levels after GalN/LPS administration. Furthermore, plasma Fn significantly inhibited liver necrosis at 9 hours after GalN/LPS injection. The fraction of apoptotic-positive cells in these plasma Fn-treated mice was significantly lower than in the control group. These results support the protective treatment of endotoxin-induced liver injury by plasma Fn.

Islet transplantation and regeneration for treatment of diabetes

Islet transplantation has the potential to restore normoglycemia and prevent the development of diabetic complications such as retinopathy, nephropathy and neuropathy, and could therefore ve a valuable treatment for diabetic patients. The scarcity of available islets is an obstacle for clinically successful islet transplantation. To resolve the problems, we have examined the two methods, islet transplantation with extracellular matrix and in vivo expansion of islets with electrically-transfection of growth factors.

[Thirty years after fibronectin discovery: role in malignant transformation and in ageing]

1973 was the year of a major discovery: two proteins were shown to disappear from cell surface when cells were transformed by tumor viruses. Later on a large number of glycoproteins were recognized as identical and coined as fibronectin. In spite of 30 years of studies, interest in fibronectin remains vivid. Thanks to its study, understanding of extracellular matrix organisation, cell-matrix interactions and signalling through integrins, formation of fibronectin based fibrillar matrix made great progress. Furthermore importance of matricryptic sites emerged as well as matricryptins. Such peptides show properties that original proteins do not possess. Some of these peptides are used as therapeutic agents. On the contrary others appear to be involved in vicious circles underlying age-dependent decline of tissue function. This fascinating molecule and the parent molecules will certainly remain of interest for some time.

[Plasma fibronectin in patients during toxic goiter surgery and early postoperative period]

In 63 patients with toxic goiter the fibrinonectin content in plasma and its cryoprecipitate activity (CPA) were studied during surgical treatment conduction. There were revealed lowering of its level and CPA with subsequent lowering of this indexes in postoperative period. Application of uni-group heparinized freshly frozen plasma in therapeutic complex was proposed for hypofibronectinemia correction and for reduction of postoperative thyreotoxicosis severity.

The use of bovine porous bone mineral in combination with collagen membrane or autologous fibrinogen/fibronectin system for ridge preservation following tooth extraction

Preservation of the alveolar ridge following tooth extraction is desirable since it facilitates placement of endosseous implants and may improve the adverse esthetics often associated with fixed partial dentures. The purpose of this study was to compare the clinical effectiveness of bovine porous bone mineral (BPBM) used as a graft material combined with either guided tissue regeneration (GTR) or with the autologous fibrinogen/fibronectin system (AFFS) in preserving alveolar ridges following tooth extraction. Twenty-six patients who required extraction of two or more anterior or bicuspid teeth participated in a split-mouth design study. Following tooth extraction and elevation of a buccal full thickness flap, sockets were filled with bovine porous bone mineral which was then covered with either a collagen membrane or mixed and covered with an AFFS system. An acrylic stent served as a reference point for measurements. Primary flap closure was achieved in all surgical sites, and reentry surgery was performed at 6 months. Reentry surgery showed that BPBM/GTR sites presented with [1] significantly more internal socket bone fill (6.04 +/- 0.21 mm vs. 4.98 +/- 0.26 mm), [2] less, although not statistically significant, resorption of alveolar bone height (0.23 +/- 0.28 mm vs. 0.3 +/- 0.21 mm), and [3] significantly less horizontal resorption of the alveolar bony ridge as compared to BPBM/AFFS (1.06 +/- 0.28 mm vs. 2.60 +/- 0.25 mm). This study suggests that treatment of extraction sockets with a combination of bovine porous bone mineral and guided tissue regeneration is of slightly more benefit in preserving alveolar ridge dimensions following tooth extraction than treatment with a combination of bovine porous bone mineral and the autologous fibrinogen/fibronectin system.

Beneficial effect of pretreatment of islets with fibronectin on glucose tolerance after islet transplantation

The scarcity of available islets is an obstacle for clinically successful islet transplantation. One solution might be to increase the efficacy of the limited islets. Isolated islets are exposed to a variety of cellular stressors, and disruption of the cell-matrix connections damages islets. We examined the effect of fibronectin, a major component of the extracellular matrix, on islet viability, mass and function, and also examined whether fibronectin-treated islets improved the results of islet transplantation. Islets cultured with fibronectin for 48 hours maintained higher cell viability (0.146 +/- 0.010 vs. 0.173 +/- 0.007 by MTT assay), and also had a greater insulin and DNA content (86.8 +/- 3.6 vs. 72.8 +/- 3.2 ng/islet and 35.2 +/- 1.4 vs. 30.0 +/- 1.5 ng/islet, respectively) than islets cultured without fibronectin (control). Absolute values of insulin secretion were higher in fibronectin-treated islets than in controls; however, the ratio of stimulated insulin secretion to basal secretion was not significantly different (206.9 +/- 23.3 vs. 191.7 +/- 20.2% when the insulin response to 16.7 mmol/l glucose was compared to that of 3.3 mmol/l glucose); the higher insulin secretion was thus mainly due to larger islet cell mass. The rats transplanted with fibronectin-treated islets had lower plasma glucose and higher plasma insulin levels within 2 weeks after transplantation, and had more favorable glucose tolerance 9 weeks after transplantation. These results indicate that cultivation with fibronectin might preserve islet cell viability, mass and insulin secretory function, which could improve glucose tolerance following islet transplantation.

Evaluation of cellular response to collagen membranes enriched with fibronectin light and transmission electron microscope study

This study was undertaken to evaluate the biocompatibility, cellular reaction and resorption characteristics of a type I bovine collagen membrane material either enriched with or without fibronectin solution in vivo using light (LM) and transmission electron microscopy (TEM). Experimental osseous dehiscence defects were surgically produced bilaterally on the labial aspect of the mandibular 2nd, 3rd, and 4th premolar teeth in four mongrel dogs. Collagen membranes rehydrated with fibronectin solution (group FM) and membranes rehydrated with saline (group M) were placed over the bony defects. The third premolar teeth on which the flap operation was performed served as control (group C), with no membrane placed. Flaps were positioned slightly coronally and sutured. Gingival tissue samples and block biopsies were obtained from all experimental and control sites for LM and TEM evaluation at 7 days. For each group, morphometric analysis was performed and the numbers of macrophages in the most coronal area of the free gingiva were counted. Postoperative healing was uneventful during the experimental period, and all membranes remained covered. Light microscopic evaluation revealed similar resorption patterns in the most coronal area of the membranes both enriched with and without fibronectin solution within the first 7 days. The mean numbers of macrophages were higher in experimental groups than in the control group. In TEM evaluation, more excessive intracellular macrophage activity was observed in group M than group FM. As a result of these observations it may be concluded that similar resorption characteristics existed in the most coronal area in both experimental groups with LM evaluation, but with TEM it was observed that the membranes enriched with fibronectin solution were resorbed more slowly at the ultrastructural level.

Effect of a collagen membrane enriched with fibronectin on guided tissue regeneration in dogs

The present study was planned to assess the capacity of a resorbable collagen membrane enriched with fibronectin to prevent the apical migration of epithelium and to facilitate new attachment and new bone. Experimental osseous dehiscence defects were produced on the bilateral labial aspect of mandibular 2nd, 3rd and 4th premolar teeth in six mongrel dogs. Guided tissue regeneration therapy using collagen membranes, which were rehydrated with fibronectin solution, was performed on one quadrant (group A). In the contralateral quadrant, the same collagen membranes, but rehydrated only with saline (group B), were placed over the bony defects. The third premolar teeth, which were treated by open-flap debridement, served as control (group C). Flaps were positioned slightly coronally and sutured; sutures were removed 10 days later. The dogs were killed 30 days after reconstructive therapy. Tissue blocks containing the experimental and control teeth were excised, demineralized in EDTA, and embedded in paraffin. Histological and histometric evaluation revealed that all groups demonstrated similar effects on preventing the down-growth of epithelium and formation of new cementum and new bone. Collagen membranes were tolerated well within the tissues, and membrane remnants were identified at 30 days. In summary, this study indicated that in this dog model similar healing results could be achieved with a bovine type I collagen membrane with or without fibronectin solution and open-flap debridement.

Human plasma fibronectin potentiates the mitogenic activity of platelet-derived growth factor and complements its wound healing effects

Integrin-mediated cell adhesion and growth factor stimuli are both required for optimal control of cell proliferation. In the context of skin injury, cell-derived fibronectin and platelet-derived growth factor play important roles in the stimulation of cell proliferation and migration, activities that are crucial to the healing process. To assess the ability of exogenously supplied plasma-derived fibronectin to stimulate wound repair and to study its ability to cooperate with platelet-derived growth factor-BB during healing, we devised a novel topical delivery formulation that allows the controlled release of both molecules to a wound. Using this topical formulation and the rabbit ear model of dermal wound healing, we show that plasma fibronectin is a potent stimulator of the wound healing process. We also show that administration of fibronectin and platelet-derived growth factor-BB in combination has additive wound healing effects. Finally, we report novel findings on the ability of soluble plasma fibronectin to potentiate the mitogenic effects of platelet-derived growth factor-BB in vitro. These findings not only show that optimal concentrations of exogenous fibronectin administered using an effective delivery system stimulate wound healing; they also suggest that PDGF-BB should be administered with fibronectin to achieve optimal therapeutic stimulation of wound healing.

Stimulating regeneration in the damaged spinal cord

Great progress has been made in recent years in experimental strategies for spinal cord repair. In this review we describe two of these strategies, namely the use of neurotrophic factors to promote functional regeneration across the dorsal root entry zone (DREZ), and the use of synthetic fibronectin conduits to support directed axonal growth. The junction between the peripheral nervous system (PNS) and central nervous system (CNS) is marked by a specialized region, the DREZ, where sensory axons enter the spinal cord from the dorsal roots. After injury to dorsal roots, axons will regenerate as far as the DREZ but no further. However, recent studies have shown that this barrier can be overcome and function restored. In animals treated with neurotrophic factors, regenerating axons cross the DREZ and establish functional connections with dorsal horn cells. For example, intrathecal delivery of neurotrophin 3 (NT3) supports ingrowth of A fibres into the dorsal horn. This ingrowth is revealed using a transganglionic anatomical tracer (cholera toxin subunit B) and analysis at light and electron microscopic level. In addition to promoting axonal growth, spinal cord repair is likely to require strategies for supporting long-distance regeneration. Synthetic fibronectin conduits may be useful for this purpose. Experimental studies indicate that fibronectin mats implanted into the spinal cord will integrate with the host tissue and support extensive and directional axonal growth. Growth of both PNS and CNS axons is supported by the fibronectin, and axons become myelinated by Schwann cells. Ongoing studies are aimed at developing composite conduits and promoting axonal growth from the fibronectin back into the spinal cord.

[Changes in cell immunity indexes under the influence of thymalin, thyroxine and fibronectin in patients with hyperplastic diseases of thyroid gland before and after the surgery]

Changes in the cell immunity indexes under the influence of thymalin, thyroxin and fibronectin in vitral loading models were studied up in patients with hyperplastic diseases of the thyroid gland. Disbalance of the cell link immunity was revealed before the operation and, in particular, in the main subpopulations of lymphocytes as well as immunoregulating index lowering, which had intensified after the operation. In patients with toxic, nodose euthyroid goiter and chronic autoimmune thyroiditis the existence of (thyroxin- and thymalin) dependent control of the cell link immunity was determined. Application of fibronectin substituting therapy for correction of the hormone depending functional activity of lymphocytes in the early postoperative period in patients with hyperplastic diseases of thyroid gland was pathogenetically substantiated.

A fibronectin fragment inhibits tumor growth, angiogenesis, and metastasis

We have shown previously that a polymeric form of fibronectin is strongly antimetastatic when administered systemically to tumor-bearing mice. The polymeric fibronectin, sFN, is formed in vitro by treating soluble fibronectin with a 76-aa peptide, III1-C, which is derived from the first type III repeat in fibronectin. Here we show that the III1-C peptide and sFN also reduce tumor growth in mice, and that this effect correlates with a low density of blood vessels in the tumors of the treated mice. III1-C also polymerized fibrinogen, and the fibrinogen polymer, sFBG, had antitumor and antiangiogenic effects similar to those of sFN. Mice that had been injected s.c. with three different types of human tumor cells and treated with biweekly i.p. injections of III1-C, sFN, or sFBG over a 5-week period had tumors that were 50-90% smaller than those of control mice. Blood vessel density in the tumors of the treated mice was reduced by 60-80% at the end of the experiment. Xenograft tumors from a human breast carcinoma line (MDA-MB-435) were particularly susceptible to these treatments. Metastasis into the lungs from the primary s.c. tumors also was inhibited in the mice treated with III1-C and the two polymers. The III1-C peptide is an antiangiogenic and antimetastatic agent. Because of its ability to suppress tumor growth, angiogenesis, and metastasis, we have named the III1-C peptide anastellin [from anastello (Greek), inhibit, force a retreat].

Hemophilia treatment. Predicting the long-term risk of HIV exposure by cryoprecipitate

Most of the world's haemophilia population lives in countries with few medical or financial resources. As such, they cannot easily obtain viral-inactivated clotting product. Many patients are treated with cryoprecipitate made from locally supplied blood. The reasoning for using cryoprecipitate, instead of viral-inactivated products, is based on an unspoken belief that because blood banks can provide reasonably safe products by using modern testing procedures, transmission of HIV and other blood-borne viruses is rare. However, the risk of acquiring a blood-borne infection increases with every exposure, and haemophilia patients treated with cryoprecipitate or fresh-frozen plasma are exposed to hundreds or thousands of donors during their lifetime. The risk that a person infected with HIV will donate blood during the 'window period' is directly related to the incidence of HIV in the country where the donation occurs. To demonstrate the extent of this problem, we devised a model for estimating the risk that a person with haemophilia will encounter HIV-contaminated cryoprecipitate based on the years of treatment and the underlying incidence rate of HIV among blood donors. We applied the model to two countries with different incidence rates of HIV: Venezuela and the United States. We found that a person with haemophilia who receives monthly infusions of cryoprecipitate prepared from plasma of 15 donors over a lifetime of treatment (60 years) is at significant risk of being exposed to HIV. In the United States there is a 2% risk of being exposed to HIV-contaminated blood product, and in Venezuela, the percentage of risk is 40%. Given this degree of risk, medical care providers should carefully evaluate the use of cryoprecipitate except in emergencies or when no viral-inactivated products are available.

[Construction of expression plasmids harbouring genes encoding recombinant FN polypeptides with triple-domain and preliminary characterization of the products expressed in Escherichia coli]

To investigate the important role of recombinant triple-domain FN polypeptide in tumor therapy, two expression plasmids pF94-62 and pF94-82 were constructed and used to express triple-domain polypeptides of human FN in E. coli. The expressed polypeptides were CH62 (Pro 1239-Ser 1515 of FN linked with Ala 1690-Val 2049 through Met) and CH82 (CH62 without Pro 1953-Glu 1978). CH82 polypeptide was expressed as inclusion bodies in E. coli cultured at 37 degrees C. After denaturation with 8 mol/L urea and renaturation, the polypeptides were purified by the affinity chromatograph with Heparin-agarose, and the purified product was analysed by cell adhesion assay. The expression level of CH62 in E. coli was very low(5%), but that of CH82 was very high (21%), it suggested that N terminal sequence of Cell II in FN was the key sequence which influence the expression of triple-domain polypeptide in E. coli. The purified product was capable of binding heparin and cells, and it had a better binding activity than bifunctional-domain FN polypeptides. The production of CH82 polypeptide provided a fundamental basis for further study of recombinant product with better function of anti-metastasis and immune regulation.

[The inhibitory effect of recombinant fibronectin polypeptide CH50 on the growth of B16 melanoma]

OBJECTIVE

To study the inhibitory effect of CH50, a recombinant polypeptide consisting of 2 binding domains of human fibronectin, on the growth of B16/F1 melanoma in mice.

METHODS

Mice inoculated with B16/F1 cells were treated with CH50. The growth inhibitory effect on i.p. inoculated tumor was assessed by the number and size of tumor nodules in the peritoneal cavity, and on s.c. inoculated tumor by tumor size.

RESULTS

For s.c. inoculated B16/F1, CH50 injected at the tumor site led to 50% inhibition of tumor growth while injection at a distant site was much less effective. In mice bearing i.p. inoculated tumor, the growth inhibition by CH50 on tumor nodules < 1 mm in diameter was 80% and 50+% on those > 1 mm. Synergistic therapeutic effect was obtained when CH50 used in combination with hydroxycamptothecine (HCPT).

CONCLUSION

CH50 is effective in the treatment of B16/F1 melanoma. The effect can be enhanced when used in combination with HCPT.