In Situ Transglutaminase Cross-Linking Improves Mechanical Properties of Self-Assembling Peptides for Biomedical Applications.

The development of three-dimensional (3D) biomaterials that mimic natural tissues is required for efficiently restoring physiological functions of injured tissues and organs. In the field of soft hydrogels, self-assembled peptides (SAPs) stand out as distinctive biomimetic scaffolds, offering tunable properties. They have garnered significant attention in nanomedicine due to their innate ability to self-assemble, resulting in the creation of fibrous nanostructures that closely mimic the microenvironment of the extracellular matrix (ECM). This unique feature ensures their biocompatibility and bioactivity, making them a compelling area of study over the past few decades. As they are soft hydrogels, approaches are necessary to enhance the stiffness and resilience of the SAP materials. This work shows an enzymatic strategy to selectively increase the stiffness and resiliency of functionalized SAPs using transglutaminase (TGase) type 2, an enzyme capable of triggering the formation of isopeptide bonds. To this aim, we synthesized a set of SAP sequences and characterized their cross-linking via rheological experiments, atomic force microscopy (AFM), thioflavin-T binding assay, and infrared spectroscopy (ATR-FTIR) tests. The results showed an improvement of the storage modulus of cross-linked SAPs at no cost of the maximum stress-at-failure. Further, in in vitro tests, we examined and validated the TGase capability to cross-link SAPs without hampering seeded neural stem cells (hNSCs) viability and differentiation, potentially leaving the door open for safe in situ cross-linking reactions in vivo.

Dynamic surgical anatomy using 3D reconstruction technology in complex hepato-biliary surgery with vascular involvement. Results from an international multicentric survey.

INTRODUCTION: Three-dimensional liver modeling can lead to substantial changes in choosing the type and extension of liver resection. This study aimed to explore whether 3D reconstruction helps to better understand the relationship between liver tumors and neighboring vascular structures compared to standard 2D CT scan images. METHODS: Contrast-enhanced CT scan images of 11 patients suffering from primary and secondary hepatic tumors were selected. Twenty-three experienced HBP surgeons participated to the survey. A standardized questionnaire outlining 16 different vascular structures (items) having a potential relationship with the tumor was provided. Intraoperative and histopathological findings were used as the reference standard. The proper hypothesis was that 3D accuracy is greater than 2D. As a secondary endpoint, inter-raters' agreement was explored. RESULTS: The mean difference between 3D and 2D, was 2.6 points (SE: 0.40; 95 % CI: 1.7-3.5; p < 0.0001). After sensitivity analysis, the results favored 3D visualization as well (mean difference 1.7 points; SE: 0.32; 95 % CI: 1.0-2.5; p = 0.0004). The inter-raters' agreement was moderate for both methods (2D: W = 0.45; 3D: W = 0.44). CONCLUSION: 3D reconstruction may give a significant contribution to better understanding liver vascular anatomy and the precise relationship between the tumor and the neighboring structures.

Exploitation of Olive (Olea europaea L.) Seed Proteins as Upgraded Source of Bioactive Peptides with Multifunctional Properties: Focus on Antioxidant and Dipeptidyl-Dipeptidase-IV Inhibitory Activities, and Glucagon-like Peptide 1 Improved Modulation.

Agri-food industry wastes and by-products include highly valuable components that can upgraded, providing low-cost bioactives or used as an alternative protein source. In this context, by-products from olive production and olive oil extraction process, i.e., seeds, can be fostered. In particular, this work was aimed at extracting and characterizing proteins for Olea europaea L. seeds and at producing two protein hydrolysates using alcalase and papain, respectively. Peptidomic analysis were performed, allowing to determine both medium- and short-sized peptides and to identify their potential biological activities. Moreover, an extensive characterization of the antioxidant properties of Olea europaea L. seed hydrolysates was carried out both in vitro by 2,2-diphenyl-1-picrylhydrazyl (DPPH), by ferric reducing antioxidant power (FRAP), and by 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays, respectively, and at cellular level by measuring the ability of these hydrolysates to significant reduce the H2O2-induced reactive oxygen species (ROS) and lipid peroxidation levels in human intestinal Caco-2 cells. The results of the both hydrolysates showed significant antioxidant properties by reducing the free radical scavenging activities up to 65.0 ± 0.1% for the sample hydrolyzed with alcalase and up to 75.7 ± 0.4% for the papain hydrolysates tested at 5 mg/mL, respectively. Moreover, similar values were obtained by the ABTS assays, whereas the FRAP increased up to 13,025.0 ± 241.5% for the alcalase hydrolysates and up to 12,462.5 ± 311.9% for the papain hydrolysates, both tested at 1 mg/mL. According to the in vitro results, both papain and alcalase hydrolysates restore the cellular ROS levels up 130.4 ± 4.24% and 128.5 ± 3.60%, respectively, at 0.1 mg/mL and reduce the lipid peroxidation levels up to 109.2 ± 7.95% and 73.0 ± 7.64%, respectively, at 1.0 mg/mL. In addition, results underlined that the same hydrolysates reduced the activity of dipeptidyl peptidase-IV (DPP-IV) in vitro and at cellular levels up to 42.9 ± 6.5% and 38.7 ± 7.2% at 5.0 mg/mL for alcalase and papain hydrolysates, respectively. Interestingly, they stimulate the release and stability of glucagon-like peptide 1 (GLP-1) hormone through an increase of its levels up to 660.7 ± 21.9 pM and 613.4 ± 39.1 pM for alcalase and papain hydrolysates, respectively. Based on these results, olive seed hydrolysates may represent new ingredients with antioxidant and anti-diabetic properties for the development of nutraceuticals and functional foods for the prevention of metabolic syndrome onset.

A New Polysaccharide Carrier Isolated from Camelina Cake: Structural Characterization, Rheological Behavior, and Its Influence on Purple Corn Cob Extract's Bioaccessibility.

A polysaccharide fraction obtained from camelina cake (CCP), selected as a carrier to encapsulate purple corn cob extract (MCE), was investigated. A wide population of carbohydrate polymers (with a polydispersivity index of 3.26 ± 0.07 and an average molecular weight of about 139.749 × 103 ± 4.392 × 103 g/mol) with a gel-like behavior and a thixotropic feature characterized the fraction. MCE-CCP combinations (50-50 and 25-75, w/w), selected based on CCP encapsulation efficiency, were tested for their stability and MCE polyphenols' bioaccessibility during digestion (monitored using an in vitro static procedure). During the oral and gastric phases of the digestion process, CCP gradually swelled and totally released MCE polyphenols. MCE-CCP50 had the fastest release. Moreover, anthocyanins were still detectable during the duodenal phase, in both MCE-CCP ingredients. Furthermore, CCP (5 mg/mL) exerted in vitro potential hypocholesterolemic activity via bile salts binding during digestion.

Nanostructure, Self-Assembly, Mechanical Properties, and Antioxidant Activity of a Lupin-Derived Peptide Hydrogel.

Naturally occurring food peptides are frequently used in the life sciences due to their beneficial effects through their impact on specific biochemical pathways. Furthermore, they are often leveraged for applications in areas as diverse as bioengineering, medicine, agriculture, and even fashion. However, progress toward understanding their self-assembling properties as functional materials are often hindered by their long aromatic and charged residue-enriched sequences encrypted in the parent protein sequence. In this study, we elucidate the nanostructure and the hierarchical self-assembly propensity of a lupin-derived peptide which belongs to the α-conglutin (11S globulin, legumin-like protein), with a straightforward N-terminal biotinylated oligoglycine tag-based methodology for controlling the nanostructures, biomechanics, and biological features. Extensive characterization was performed via Circular Dichroism (CD) spectroscopy, Fourier Transform Infrared spectroscopy (FT-IR), rheological measurements, and Atomic Force Microscopy (AFM) analyses. By using the biotin tag, we obtained a thixotropic lupin-derived peptide hydrogel (named BT13) with tunable mechanical properties (from 2 to 11 kPa), without impairing its spontaneous formation of ß-sheet secondary structures. Lastly, we demonstrated that this hydrogel has antioxidant activity. Altogether, our findings address multiple challenges associated with the development of naturally occurring food peptide-based hydrogels, offering a new tool to both fine tune the mechanical properties and tailor the antioxidant activities, providing new research directions across food chemistry, biochemistry, and bioengineering.

Self-assembling peptide hydrogels for the stabilization and sustained release of active Chondroitinase ABC in vitro and in spinal cord injuries.

Activated microglia/macrophages infiltration, astrocyte migration, and increased production of inhibitory chondroitin sulfate proteoglycans (CSPGs) are standard harmful events taking place after the spinal cord injuries (SCI). The gliotic scar, viz. the outcome of chronic SCI, constitutes a long-lasting physical and chemical barrier to axonal regrowth. In the past two decades, various research groups targeted the hostile host microenvironments of the gliotic scar at the injury site. To this purpose, biomaterial scaffolds demonstrate to provide a promising potential for nervous cell restoration. We here focused our efforts on two self-assembling peptides (SAPs), featuring different self-assembled nanostructures, and on different methods of drug loading to exploit the neuroregenerative potential of Chondroitinase ABC (ChABC), a thermolabile pro-plastic agent attenuating the inhibitory action of CSPGs. Enzymatic activity of ChABC (usually lasting less than 72 hours in vitro) released from SAPs was remarkably detected up to 42 days in vitro. ChABC was continuously released in vitro from a few days to 42 days as well. Also, injections of ChABC loaded SAP hydrogels favored host neural regeneration and behavioral recovery in chronic SCI in rats. Hence, SAP hydrogels showed great promise for the delivery of Chondroitinase ABC in future therapies targeting chronic SCI.

Cross-Linked Self-Assembling Peptides and Their Post-Assembly Functionalization via One-Pot and In Situ Gelation System.

Supramolecular nanostructures formed through peptide self-assembly can have a wide range of applications in the biomedical landscape. However, they often lose biomechanical properties at low mechanical stress due to the non-covalent interactions working in the self-assembling process. Herein, we report the design of cross-linked self-assembling peptide hydrogels using a one-pot in situ gelation system, based on 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide/N-hydroxysulfosuccinimide (EDC/sulfo-NHS) coupling, to tune its biomechanics. EDC/sulfo-NHS coupling led to limited changes in storage modulus (from 0.9 to 2 kPa), but it significantly increased both the strain (from 6% to 60%) and failure stress (from 19 to 35 Pa) of peptide hydrogel without impairing the spontaneous formation of ß-sheet-containing nano-filaments. Furthermore, EDC/sulfo-NHS cross-linking bestowed self-healing and thixotropic properties to the peptide hydrogel. Lastly, we demonstrated that this strategy can be used to incorporate bioactive functional motifs after self-assembly on pre-formed nanostructures by functionalizing an Ac-LDLKLDLKLDLK-CONH2 (LDLK12) self-assembling peptide with the phage display-derived KLPGWSG peptide involved in the modulation of neural stem cell proliferation and differentiation. The incorporation of a functional motif did not alter the peptide's secondary structure and its mechanical properties. The work reported here offers new tools to both fine tune the mechanical properties of and tailor the biomimetic properties of self-assembling peptide hydrogels while retaining their nanostructures, which is useful for tissue engineering and regenerative medicine applications.

"Bottom-Up" Strategy for the Identification of Novel Soybean Peptides with Angiotensin-Converting Enzyme Inhibitory Activity.

IAVPTGVA (Soy1) and LPYP are two soybean peptides, which display a multifunctional behavior, showing in vitro hypocholesterolemic and hypoglycemic activities. A preliminary screening of their structures using BIOPEP suggested that they might be potential angiotensin-converting enzyme (ACE) inhibitors. Therefore, a bottom-up-aided approach was developed in order to clarify the in vitro hypotensive activity. Soy1 and LPYP dropped the intestinal and renal ACE enzyme activity with IC50 values equal to 14.7 ± 0.28 and 5.0 ± 0.28 µM (Caco-2 cells), and 6.0 ± 0.35 and 6.8 ± 0.20 µM (HK-2 cells), respectively. In parallel, a molecular modeling study suggested their capability to act as competitive inhibitors of this enzyme. Finally, in order to increase both their stability and hypotensive properties, a suitable strategy for the harmless control of their release from a nanomaterial was developed through their encapsulation into the RADA16-assembling peptide.

High Versus Low Ligation of the Inferior Mesenteric Artery During Rectal Resection for Cancer: Oncological Outcomes After Three Years of Follow-Up From the HIGHLOW Trial.

Objectives: To determine the disease-free survival (DFS), disease-specific survival (DSS), and recurrence in patients who underwent laparoscopic low anterior rectal resection with total mesorectal excision (TME) with either high or low ligation of the inferior mesenteric artery (IMA). Background: The level of IMA ligation during anterior rectal resection with TME is still a matter of debate, especially in terms of oncological adequacy. Methods: Between June 2014 and December 2016, patients scheduled to undergo elective laparoscopic low anterior resection (LAR) and TME in 6 Italian nonacademic hospitals were randomized into 2 groups in the HIGHLOW Trial (ClinicalTrials.gov Identifier: NCT02153801) according to the level of IMA ligation: high ligation (HL) versus low ligation (LL). DFS, DSS, and recurrence were inquired. Recurrence was determined at 3, 6, 9, and 12 months and every 6 months thereafter. Patients and tumor characteristics as well as surgical outcomes were analyzed to identify risk factors for recurrence. Results: One hundred ninety-six patients from the HIGHLOW trial were analyzed. Median follow-up for DFS was 40.6 (interquartile range [IQR], 6-64.7) and 40 (IQR, 7.6-67.8), while median follow-up for DSS was 41.2 (IQR, 10.7-64.7) and 42.7 (IQR, 6-67.6) in the HL and LL groups, respectively. The 3-year DFS rate of HL and LL patients was 82.2% and 82.1% (P = 0.874), respectively. The 3-year DSS for HL and LL patients was 92.1% and 93.4% (P = 0.897), respectively. There was no statistically significant difference in the local recurrence rate (2% HL vs 2.1% LL), in the regional recurrence rate (3% HL vs 2.1% LL), and in the distant recurrence rate (12.9% HL vs 13.7% LL). Multivariate analysis found conversion to open surgery (hazard ratio [HR], 3.68; P = 0.001) and higher stage of disease (HR, 7.73; P < 0.001) to be significant determinant for DFS. Conclusions: The level of inferior mesenteric artery ligation during LAR and TME for rectal cancer does not affect DFS, DSS, and recurrence.

Symptomatic Uncomplicated Diverticular Disease and Incidence of Unexpected Abscess during Sigmoidectomy: A Multicenter Prospective Observational Study.

BACKGROUND: Symptomatic uncomplicated diverticular disease can affect patients' everyday routine. Considerable efforts have been made to identify clinical features that correlate to the severity of the disease. Unexpected intraoperative abscesses are reported in large retrospective series, showing how uncomplicated symptoms and presentations can underlie a complicated disease. The aim of this study was to investigate the incidence of pericolic or intramural abscess in patients undergoing elective sigmoidectomy for symptomatic uncomplicated diverticular disease and see if chronic symptoms correlate to the presence of an abscess. METHODS: Between January 2016 and June 2018, we prospectively collected data of patients who were given indication to elective sigmoidectomy for symptomatic uncomplicated diverticular disease. Patients were divided into 3 groups: acute resolving, smoldering, and atypical according to a previously described classification of uncomplicated diverticular disease. RESULTS: One hundred fifty-eight consecutive patients were enrolled in the study. The median age was 63 years (22- 88), and the mean body mass index was 26 (±7) kg/m2. There were 114 patients in the acute resolving group, 36 in the smoldering group, and 8 in the atypical group. An unexpected abscess was reported in 75 patients (47.5%) during surgery or pathological examination. The incidence of -abscess was greater for patient in the smoldering group (p = 0.0243). CONCLUSION: Our series of patients affected by symptomatic uncomplicated diverticular disease showed an incidence of unexpected pericolic or intramural abscess of 47.5%. Patients affected by smoldering diverticular disease presented a greater abscess rate.

Creation of a rectal cancer registry in Italy by the Advanced International Mini-Invasive Surgery (AIMS) academy clinical research network.

Background: The management of rectal cancer is multimodal and involves a multidisciplinary team of cancer specialists with expertise in medical oncology, surgical oncology, radiation oncology and radiology. It is crucial for highly specialized centers to collaborate via networks that aim to maintain uniformity in every aspect of treatment and rigorously gather patients' data, from the first clinical evaluation to the last follow-up visit. The Advanced International Mini-Invasive Surgery (AIMS) academy clinical research network aims to create a rectal cancer registry. This will prospectively collect the data of patients operated on for non-metastatic rectal cancer in high volume colorectal surgical units through a well design pre-fashioned database for non-metastatic rectal cancer, in order to take all multidisciplinary aspects into consideration. Methods/Design: The protocol describes a multicenter prospective observational cohort study, investigating demographics, frailty, cancer-related features, surgical and radiological parameters, and oncological outcomes among patients with non-metastatic rectal cancer who are candidates for surgery with curative intent. Patients enrolled in the present registry will be followed up for 5 years after surgery. Discussion: Standardization and centralization of data collection for neoplastic diseases is a virtuous process for patient care. The creation of a register will allow the control of the quality of treatments provided and permit prospective and retrospective studies to be carried out on complete and reliable high quality data. Establishing data collection in a prospective and systematic fashion is the only possibility to preserve the enormous resource that each patient represents.

Compliance to Adjuvant Chemotherapy of Patients Who Underwent Surgery for Rectal Cancer: Report from a Multi-institutional Research Network.

INTRODUCTION: Adjuvant chemotherapy for locally advanced rectal cancer is associated with improved overall survival. However, recent evidence from randomized trials showed a compliance rate of 43 to 73%, which may affect efficacy. The aim of this multicenter retrospective analysis was to investigate the compliance rate to adjuvant treatment for patients who underwent rectal surgery for cancer. METHODS: Patients who underwent surgery with curative intent for rectal cancer in six Italian colorectal centers between January 2013 and December 2017 were retrospectively reviewed. Exclusion criteria were age less than 18 years, palliative or emergency surgery, and stage IV disease. Parameters of interest were patients' characteristics, preoperative tumor stage, neo-adjuvant chemoradiation therapy, intra-operative and postoperative outcomes. Although the participating centers referred to the same treatment guidelines for treatment, the chemotherapy regiment was not standardized across the institutions. Reasons for not starting adjuvant chemotherapy when indicated, interruption, and modification of drug regimen were collected to investigate compliance. RESULTS: A total of 572 patients were included in the analysis. Two hundred and fifty-two (44.1%) patients received neo-adjuvant chemoradiation therapy. All patients underwent high anterior rectal resection, low anterior rectal resection, or Miles' procedure. Of 399 patients with an indication to adjuvant chemotherapy, 176 (44.1%) completed the treatment as planned. Compliance for patients who started chemotherapy was 56% (95% CI 50.4-61.6%). Sixty-six patients interrupted the treatment, 76 patients significantly reduced the drug dose, and 41 patients had to switch to other therapeutic regimens. CONCLUSIONS: The present multicenter investigation reports a low compliance rate to adjuvant chemotherapy after rectal resection for cancer. Multidisciplinary teams should focus on future effort to improve compliance for these patients.

Low Ligation of Inferior Mesenteric Artery in Laparoscopic Anterior Resection for Rectal Cancer Reduces Genitourinary Dysfunction: Results From a Randomized Controlled Trial (HIGHLOW Trial).

OBJECTIVES: The aim of the present study was to compare the incidence of genitourinary (GU) dysfunction after elective laparoscopic low anterior rectal resection and total mesorectal excision (LAR + TME) with high or low ligation (LL) of the inferior mesenteric artery (IMA). Secondary aims included the incidence of anastomotic leakage and oncological outcomes. BACKGROUND: The criterion standard surgical approach for rectal cancer is LAR + TME. The level of artery ligation remains an issue related to functional outcome, anastomotic leak rate, and oncological adequacy. Retrospective studies failed to provide strong evidence in favor of one particular vascular approach and the specific impact on GU function is poorly understood. METHODS: Between June 2014 and December 2016, patients who underwent elective laparoscopic LAR + TME in 6 Italian nonacademic hospitals were randomized to high ligation (HL) or LL of IMA after meeting the inclusion criteria. GU function was evaluated using a standardized survey and uroflowmetric examination. The trial was registered under the ClinicalTrials.gov Identifier NCT02153801. RESULTS: A total of 214 patients were randomized to HL (n = 111) or LL (n = 103). GU function was impaired in both groups after surgery. LL group reported better continence and less obstructive urinary symptoms and improved quality of life at 9 months postoperative. Sexual function was better in the LL group compared to HL group at 9 months. Urinated volume, maximum urinary flow, and flow time were significantly (P < 0.05) in favor of the LL group at 1 and 9 months from surgery. The ultrasound measured post void residual volume and average urinary flow were significantly (P < 0.05) better in the LL group at 9 months postoperatively. Time of flow worsened in both groups at 9 months compared to baseline. There was no difference in anastomotic leak rate (8.1% HL vs 6.7% LL). There were no differences in terms of blood loss, surgical times, postoperative complications, and initial oncological outcomes between groups. CONCLUSIONS: LL of the IMA in LAR + TME results in better GU function preservation without affecting initial oncological outcomes. HL does not seem to increase the anastomotic leak rate.

A Supramolecular Approach to Develop New Soybean and Lupin Peptide Nanogels with Enhanced Dipeptidyl Peptidase IV (DPP-IV) Inhibitory Activity.

Soy1 (IAVPTGVA) and Lup1 (LTFPGSAED), two peptides from soybean and lupin protein hydrolysis, have been singled out as dipeptidyl peptidase IV (DPP-IV) activity inhibitors in different model systems. However, their activity is affected by their instability toward intestinal proteases. Here, an innovative strategy based on nanogels was developed in order to increase both their stability and antidiabetic properties through encapsulation into the RADA16 peptide. The nanogel formation was stimulated by a solvent-triggered approach, allowing us to produce stable nanogels ( G' = 1826 Pa, stress-failure ≥50 Pa) with shear-thinning propensity. ThT binding assay, and ATR-FTIR spectroscopy experiments showed that nanogels self-aggregated into stable cross-ß structures providing higher resistance against proteases (ex vivo experiments) and increased bioavailability of Soy1 and Lup1 peptides (in situ experiments on Caco-2 cells). Hence, this simple and harmless nanotechnological approach could be a key-step in making innovative nanomaterials for nutraceuticals delivering.

Self-assembling peptides cross-linked with genipin: resilient hydrogels and self-standing electrospun scaffolds for tissue engineering applications.

Self-assembling peptides (SAPs) are synthetic bioinspired biomaterials that can be feasibly multi-functionalized for applications in surgery, drug delivery, optics and tissue engineering (TE). Despite their promising biocompatibility and biomimetic properties, they have never been considered real competitors of polymers and/or cross-linked extracellular matrix (ECM) natural proteins. Indeed, synthetic SAP-made hydrogels usually feature modest mechanical properties, limiting their potential applications, due to the transient non-covalent interactions involved in the self-assembling phenomenon. Cross-linked SAP-hydrogels have been recently introduced to bridge this gap, but several questions remain open. New strategies leading to stiffer gels of SAPs may allow for a full exploitation of the SAP technology in TE and beyond. We have developed and characterized a genipin cross-linking strategy significantly increasing the stiffness and resiliency of FAQ(LDLK)3, a functionalized SAP already used for nervous cell cultures. We characterized different protocols of cross-linking, analyzing their dose and time-dependent efficiency, influencing stiffness, bioabsorption time and molecular arrangements. We choose the best developed protocol to electrospin into nanofibers, for the first time, self-standing, water-stable and flexible fibrous mats and micro-channels entirely made of SAPs. This work may open the door to the development and tailoring of bioprostheses entirely made of SAPs for different TE applications.

Branched peptides integrate into self-assembled nanostructures and enhance biomechanics of peptidic hydrogels.

Self-assembling peptides (SAP) have drawn an increasing interest in the tissue engineering community. They display unquestionable biomimetic properties, tailorability and promising biocompatibility. However their use has been hampered by poor mechanical properties making them fragile soft scaffolds. To increase SAP hydrogel stiffness we introduced a novel strategy based on multiple ramifications of (LDLK)3, a well-known linear SAP, connected with one or multiple "lysine knots". Differently branched SAPs were tested by increasing the number of (LDLK)3-like branches and by adding the neuro-regenerative functional motif BMHP1 as a single branch. While pure branched peptides did not have appealing self-assembling propensity, when mixed with the corresponding linear SAP they increased the stiffness of the overall hydrogel of multiple times. Notably, optimal results (or peak) were obtained 1) at similar molar ratio (between linear and branched peptides) for all tested sequences and 2) for the branched SAPs featuring the highest number of branches made of (LDLK)3. The functional motif BMHP1, as expected, seemed not to contribute to the increase of the storage modulus as efficiently as (LDLK)3. Interestingly, branched SAPs improved the ß-sheet self-arrangement of (LDLK)3 and allowed for the formation of assembled nanofibers. Indeed in coarse-grained molecular dynamics we showed they readily integrate in the assembled aggregates providing "molecular connections" among otherwise weakly paired ß-structures. Lastly, branched SAPs did not affect the usual response of human neural stem cells cultured on (LDLK)3-like scaffolds in vitro. Hence, branched SAPs may be a valuable new tool to enhance mechanical properties of self-assembling peptide biomaterials harmlessly; as neither chemical nor enzymatic cross-linking reactions are involved. As a consequence, branched SAPs may enlarge the field of application of SAPs in tissue engineering and beyond. STATEMENT OF SIGNIFICANCE: Self-assembling peptides stand at the forefront of regenerative medicine because they feature biomimetic nano-architectures that mimic the complexity of natural peptide-based extracellular matrices of living tissues. Their superior biocompatibility and ease of scale-up production are hampered by weak mechanical properties due to transient non-covalent interactions among and within the self-assembled peptide chains, thus limiting their potential applications. We introduced new branched self-assembling peptides to be used as "molecular connectors" among self-assembled nanostructures made of linear SAPs. Branched SAPs could be mixed with linear SAPs before self-assembling in order to have them intermingled with different ß-sheets of linear SAPs after gelation. This strategy caused a manifold increase of the stiffness of the assembled hydrogels (proportional to the number of self-assembling branches), did not affect SAP propensity to form ß-sheet but, instead, further stimulated their secondary structure rearrangements. It is now possible to modularly improve SAP scaffold mechanical properties without using harmful chemical reactions. Therefore, branched SAPs represent an additional tool to be adopted for efficient and harmless SAP scaffold customization in tissue engineering.

Routine clinical application of virtual reality in abdominal surgery.

BACKGROUND: The advantages of 3D reconstruction, immersive virtual reality (VR) and 3D printing in abdominal surgery have been enunciated for many years, but still today their application in routine clinical practice is almost nil. We investigate their feasibility, user appreciation and clinical impact. MATERIAL AND METHODS: Fifteen patients undergoing pancreatic, hepatic or renal surgery were studied realizing a 3D reconstruction of target anatomy. Then, an immersive VR environment was developed to import 3D models, and some details of the 3D scene were printed. All the phases of our workflow employed open-source software and low-cost hardware, easily implementable by other surgical services. A qualitative evaluation of the three approaches was performed by 20 surgeons, who filled in a specific questionnaire regarding a clinical case for each organ considered. RESULTS: Preoperative surgical planning and intraoperative guidance was feasible for all patients included in the study. The vast majority of surgeons interviewed scored their quality and usefulness as very good. CONCLUSIONS: Despite extra time, costs and efforts necessary to implement these systems, the benefits shown by the analysis of questionnaires recommend to invest more resources to train physicians to adopt these technologies routinely, even if further and larger studies are still mandatory.

Fabrication of nanofibrous electrospun scaffolds from a heterogeneous library of co- and self-assembling peptides.

Self-assembling (SAPs) and co-assembling peptides (CAPs) are driving increasing enthusiasm as synthetic but biologically inspired biomaterials amenable of easy functionalization for regenerative medicine. On the other hand, electrospinning (ES) is a versatile technique useful for tailoring the nanostructures of various biomaterials into scaffolds resembling the extracellular matrices found in organs and tissues. The synergistic merging of these two approaches is a long-awaited advance in nanomedicine that has not been deeply documented so far. In the present work, we describe the successful ES of a library of diverse SAPs and CAPs into biomimetic nanofibrous mats. Our results suggest that suitable ES solutions are characterized by high concentrations of peptides, providing backbone physical chain entanglements, and by random coil/α-helical conformations while ß-sheet aggregation may be detrimental to spinnability. The resulting peptide fibers feature interconnected seamless mats with nanofibers average diameters ranging from ∼100nm to ∼400nm. Also, peptide chemical nature and ES set up parameters play pivotal roles in determining the conformational transitions and morphological properties of the produced nanofibers. Far from being an exhaustive description of the just-opened novel field of ES-assembled peptides, this seminal work aims at shining a light on a still missing general theory for the production of electrospun peptidic biomaterials bringing together the spatial, biochemical and biomimetic of these two techniques into unique scaffolds for tissue engineering. STATEMENT OF SIGNIFICANCE: Construction of peptide hydrogels has received considerable attention due to their potential as nanostructures amenable of easy functionalization and capable of creating microenvironments suited for culturing cells and triggering tissue regeneration. They display a superior biocompatibility unmatched by other known synthetic biomaterials so far. However, their applications are confined to body fillers because most of them do spontaneously form hydrogels, while effective tissue regeneration often requires well-defined fibrous scaffolds. In this work, we developed electrospun fibers of various peptides (cross-beta self-assembling, hierarchically assembling, functionalized, co-assembling) and we provided a deep understanding of the crucial phenomena to be taken into account when peptides fibers fabrication. These results open new venues for exploring novel regenerative applications of peptide nanofibrous scaffolds.

Tumor response evaluation after neoadjuvant chemotherapy in locally advanced gastric adenocarcinoma: a prospective, multi-center cohort study.

BACKGROUND: To verify the prognostic value of the pathologic and radiological tumor response after neoadjuvant chemotherapy in the treatment of locally advanced gastric adenocarcinoma. METHODS: A total of 67 patients with locally advanced gastric cancer (clinical ≥ T2 or nodal disease and without evidence of distant metastases) underwent perioperative chemotherapy (ECF or ECX regimen) from December 2009 through June 2015 in two surgical units. Histopathological and radiological response to chemotherapy were evaluated by using tumor regression grade (TRG) (Becker's criteria) and volume change assessed by CT. RESULTS: Fifty-one (86%) patients completed all chemotherapy scheduled cycles successfully and surgery was curative (R0) in 64 (97%) subjects. The histopathological analysis showed 19 (29%) specimens with TRG1 (less than 10% of vital tumor left) and 25 (37%) patients had partial or complete response (CR) assessed by CT scan. Median disease free survival (DFS) and overall survival (OS) were 25.70 months (range, 14.52-36.80 months) and 36.60 months (range, 24.3-52.9 months), respectively. The median follow up was 27 months (range, 5.00-68.00 months). Radiological response and TRG were found to be a prognostic factor for OS and DFS, while tumor histology was not significantly related to survival. CONCLUSIONS: Both radiological response and TRG have been shown as promising survival markers in patients treated with perioperative chemotherapy for locally advanced gastric cancer. Other predictive markers of response to chemotherapy are strongly required.

Peptidic Biomaterials: From Self-Assembling to Regenerative Medicine.

Peptidic biomaterials represent a particularly exciting topic in regenerative medicine. Peptidic scaffolds can be specifically designed for biomimetic customization for targeted therapy. The field is at a pivotal point where preclinical research is being translated into clinics, so it is crucial to understand the theory and describe the status of this rapidly developing technology. In this review, we highlight major advantages and current limitations of self-assembling peptide-based biomaterials, and we discuss the most widely used classes of assembling peptides, describing recent and promising approaches in tissue engineering, drug delivery, and clinics. We also suggest design strategies and hurdles that still need to be overcome to fully exploit their therapeutic potential.