Trophic and neurotrophic factors in human pituitary adenomas (Review)

The pituitary gland is an organ that functionally connects the hypothalamus with the peripheral organs. The pituitary gland is an important regulator of body homeostasis during development, stress, and other processes. Pituitary adenomas are a group of tumors arising from the pituitary gland: they may be subdivided in functional or non-functional, depending on their hormonal activity. Some trophic and neurotrophic factors seem to play a key role in the development and maintenance of the pituitary function and in the regulation of hypothalamo-pituitary-adrenocortical axis activity. Several lines of evidence suggest that trophic and neurotrophic factors may be involved in pituitary function, thus suggesting a possible role of the trophic and neurotrophic factors in the normal development of pituitary gland and in the progression of pituitary adenomas. Additional studies might be necessary to better explain the biological role of these molecules in the development and progression of this type of tumor. In this review, in light of the available literature, data on the following neurotrophic factors are discussed: ciliary neurotrophic factor (CNTF), transforming growth factors β (TGF‑β), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF), vascular endothelial growth inhibitor (VEGI), fibroblast growth factors (FGFs) and epidermal growth factor (EGF) which influence the proliferation and growth of pituitary adenomas

Nanopatterned acellular valve conduits drive the commitment of blood-derived multipotent cells

Considerable progress has been made in recent years toward elucidating the correlation among nanoscale topography, mechanical properties, and biological behavior of cardiac valve substitutes. Porcine TriCol scaffolds are promising valve tissue engineering matrices with demonstrated self-repopulation potentiality. In order to define an in vitro model for investigating the influence of extracellular matrix signaling on the growth pattern of colonizing blood-derived cells, we cultured circulating multipotent cells (CMC) on acellular aortic (AVL) and pulmonary (PVL) valve conduits prepared with TriCol method and under no-flow condition. Isolated by our group from Vietnamese pigs before heart valve prosthetic implantation, porcine CMC revealed high proliferative abilities, three-lineage differentiative potential, and distinct hematopoietic/endothelial and mesenchymal properties. Their interaction with valve extracellular matrix nanostructures boosted differential messenger RNA expression pattern and morphologic features on AVL compared to PVL, while promoting on both matrices the commitment to valvular and endothelial cell-like phenotypes. Based on their origin from peripheral blood, porcine CMC are hypothesized in vivo to exert a pivotal role to homeostatically replenish valve cells and contribute to hetero- or allograft colonization. Furthermore, due to their high responsivity to extracellular matrix nanostructure signaling, porcine CMC could be useful for a preliminary evaluation of heart valve prosthetic functionality

In vitro assessment of a novel composite scaffold for articular cartilage restoration

Articular cartilage (AC) lesions are a particular challenge for regenerative medicine due to cartilage low self-ability repair in case of damage. Hence, a significant goal of musculoskeletal tissue engineering is the development of suitable structures in virtue of their matrix composition and biomechanical properties [1]. The objective of our study was to design in vitro a supporting structure for cartilage chondrocytes to treat focal articular joint defects. We realized a bio-hybrid composite scaffold combining decellularized Wharton’s jelly (W’s J) with the biomechanical properties of the synthetic hydrogel polyvinyl alcohol (PVA). The hydrogel itself and the more specific decellularized cartilage matrix were used as controls. Immunohistochemical analysis highlighted a similar histomorphology for W’s J and AC matrices. Human chondrocytes were isolated from articular cartilage by collagenase II digestion and then characterized by flow-cytometry and RT-PCR to assess the expression of specific markers. CD44+/CD73+/CD151+ chondrocytes were seeded on PVA, PVA/AC and PVA/W’s J scaffolds to test their ability to support cell colonization. According to SEM micrographs and MTT proliferation assay, PVA/W’s J revealed a singular attitude to sustain cell proliferation despite its aspecific origin. Our preliminary evidences highlighted the chance of using Wharton’s jelly in combination with PVA hydrogels as an innovative and easily available scaffold for cartilage restoration

Preliminary investigation of blood vessel-derived acellular matrix for vascular graft application

Although autologous vascular grafts and artificial materials have been used for reconstruction of small diameter (<5mm) blood vessels, the poor availability of vessels and the occurrence of intimal hyperplasia and progressive atherosclerotic degeneration represent shortcomings of these vascular prostheses. Therefore, this preliminary study aimed to develop acellular matrix (AM)-based vascular grafts. Rat thoracic aortas were decellularized by means of a detergent-enzymatic treatment [1], whereas endothelial cells (ECs) were obtained through enzymatic digestion of rat skin followed by immunomagnetic separation of CD31-positive cells. Twenty male Lewis rats (8 week old) received either only AM and previously in vitro reendothelized AM as abdominal aorta Interposition grafts (about 2 cm). After 1 (n=10) and 3 (n=10) months from surgery, grafts were explanted and morphologically examined by scanning electron microscopy and Movat staining. The detergent enzymatic treatment completely removed the cellular part of vessels and both MHC class I and class II antigens. After 1 month from surgery, the luminal surface of implanted AMs was partially covered by ECs and several platelets adhered in the areas lacking cell coverage. Intimal hyperplasia, already detected after 1 month, increased at 3 months. On the contrary, all the grafts composed by AM and ECs were completely covered at 1 month and their structure was similar to that of native vessels at 3 months. Taken together, our findings show that prostheses composed of AM pre-seeded with ECs could be a promising approach for the replacement of blood vessels

In vitro and in vivo study of a novel biodegradable synthetic conduit for injured peripheral nerves

In case of peripheral nerve injury (PNI) with wide substance-loss, surgical reconstruction is still a challenge. Bridging the gap by autologous sensory nerves as grafts is the current standard; nevertheless, the related issues have prompted the research towards the development of effective artificial synthetic/biological nerve conduits (NCs). Here, we manufactured a novel NC using oxidized polyvinyl alcohol (OxPVA) that is a biodegradable cryogel recently patented by our group [1]. Thus, its characteristics were compared with neat polyvinyl alcohol (PVA) and silk-fibroin (SF) NCs through in vitro/in vivo analysis. Considering in vitro studies, a morphological characterization was performed by Scanning Electron Microscopy (SEM). Thereafter, cell adhesion and proliferation of a Schwann-cell line (SH-SY5Y) were evaluated by SEM and MTT assay. Regarding in vivo tests, the NCs were implanted into the surgical injured sciatic nerve (gap: 5 mm) of Sprague-Dawley rats, and the functional recovery was assessed after 12-weeks. The NCs were then processed for histological, immunohistochemical (anti-CD3; -β-tubulin; -S100) and Transmission Electron Microscopy (TEM) analyses. In particular, morphometric analyses (section area, total number and density of nerve fibers) were performed at the level of proximal, central and distal portions with respect to NC. In vitro results by SEM showed that PVA and SF supports have a smoother surface than OxPVA scaffolds. Moreover, unlike SF scaffolds, PVA-based ones do not support SH-SY5Y adhesion and proliferation. Regarding the in vivo study, all animals showed a functional recovery with normal walk, even though only animals implanted with PVA and SF NCs sometimes showed spasms while walking. On the contrary, animals implanted with OxPVA NCs exhibited a normal movement. Anti-CD3 immunohistochemistry assessed the absence of severe inflammatory reactions in all the grafts. A strong positive immunoreaction for β-tubulin and S100 demonstrated the good regeneration of nervous fibers. TEM highlighted regeneration of myelinated/un-myelinated axons and Schwann cells in all the grafts. However, morphometric analysis demonstrated that OxPVA assure a better outcome in nerve regeneration in terms of total number of nerve fibers. Our results sustain the potential of OxPVA for the development of NCs useful for PNI with substance loss with the advantage of biodegradation

Effects of surface topography on growth and osteogenic differentiation of human mesenchymal stem cells

The clinical success of an endosseous artificial implant is related to the quality of its osseointegration with the surrounding living bone. To achieve a stable anchorage, mesenchymal cells, migrating to the implant surface from the surrounding tissue, must differentiate towards mature osteoblasts rather than connective tissue cell types. It is well known that the cell response is affected by the physicochemical parameters of the biomaterial surface, such as surface energy, surface charges or chemical composition. Topography seems to be one of the most crucial physical cues for cells (1). In particular, interactions between mesenchymal stem cells (MSCs) and surfaces with specific micro and nano patterns can stimulate MSCs to produce bone mineral in vitro (2). Herein, stamps reporting different micro and nano features were fabricated in order to obtain several corresponding replicas in a short time through microinjec- tion molding. Then, the effects of the substrate topography on human bone marrowderived MSC adhesion, proliferation, and osteogenic differentiation were investigated in the absence of inductive growth factors. Collectively, our data show that both micro- and nano-structured surfaces possess osteoinductive properties. A relationship between dimensional feature of surface topography and differentiative potential was noted. On the contrary, cell adhesion and proliferation seemed to be unaffected. Further in vivo studies will be carried out to confirm the osteoinductive properties of selected surface geometries

Umbilical cord mesenchymal stem cells modulate dextran sulphate sodium induced acute colitis in immunodeficient mice.

Inflammatory bowel diseases (IBD) are complex multi-factorial diseases with increasing incidence worldwide but their treatment is far from satisfactory. Unconventional strategies have consequently been investigated, proposing the use of stem cells as an effective alternative approach to IBD. In the present study we examined the protective potential of exogenously administered human umbilical cord derived mesenchymal stem cells (UCMSCs) against Dextran Sulphate Sodium (DSS) induced acute colitis in immunodeficient NOD.CB17-Prkdc scid/J mice with particular attention to endoplasmic reticulum (ER) stress. METHODS: UCMSCs were injected in NOD.CB17-Prkdc scid/J via the tail vein at day 1 and 4 after DSS administration. To verify attenuation of DSS induced damage by UCMSCs, Disease Activity Index (DAI) and body weight changes was monitored daily. Moreover, colon length, histological changes, myeloperoxidase and catalase activities, metalloproteinase (MMP) 2 and 9 expression and endoplasmic reticulum (ER) stress related proteins were evaluated on day 7. RESULTS: UCMSCs administration to immunodeficient NOD.CB17-Prkdc scid/J mice after DSS damage significantly reduced DAI (1.45\u2009\ub1\u20090.16 vs 2.08\u2009\ub1\u20090.18, p\u20093-fold), which were significantly reduced in mice receiving UCMSCs. Moreover, positive modulation in ER stress related proteins was observed after UCMSC administration. CONCLUSIONS: Our results demonstrated that UCMSCs are able to prevent DSS-induced colitis in immunodeficient mice. Using these mice we demonstrated that our UCMSCs have a direct preventive effect other than the T-cell immunomodulatory properties which are already known. Moreover we demonstrated a key function of MMPs and ER stress in the establishment of colitis suggesting them to be potential therapeutic targets in IBD treatment

Short Bowel Syndrome and Tissue Engineering: a preliminary study towards the development of a new regenerative approach in paediatric patients

Pediatric Short Bowel Syndrome (SBS) is a malabsorption state following massive surgical resections of the small intestine. The current therapeutic options issues (i.e. parental nutrition, surgical lengthening, transplantation) have prompt the research in Tissue Engineering. Thus, our aim was to preliminary investigate in vitro/in vivo two composite scaffolds for engineering the small intestine without resorting to autologous intestinal epithelial organoid units which, to date, are the cell source mainly considered for this purpose. In particular, we developed composite supports consisting of a novel biocompatible/resorbable cryogel that is oxidized polyvinyl alcohol (OxPVA) [1] crosslinked with intestinal mucosa whole (wIM/OxPVA) or homogenized (hIM/OxPVA). After evaluating the scaffolds by histology and Scanning Electron Microscopy (SEM), we assessed their interaction with adipose mesenchymal stem cells. Thereafter, the in vivo behavior of scaffolds was studied implanting them in the omentum of Sprague Dawley rats. At 4 weeks, explants were processed by histology and immunohistochemistry (CD3; F4/80; Ki-67; desmin; α-SMA; MNF116). Considering the in vitro evidence, both histological and SEM results proved the effectiveness of the decellularization, and allowed to appreciate the preservation of intestinal villi of the wIM as well as the characteristic features of the hIM. At 7 days from cell seeding, MTT assay showed that hIM/OxPVA scaffolds could support cell adhesion/proliferation even if the wIM/OxPVA ones seem to significantly increase cell growth (

Characterization of novel autologous leukocyte fibrin platelet membranes for tissue engineering applications

Autologous hemocomponents have recently emerged as potential biologic tools for regenerative purpose, consisting mainly of platelet concentrates which locally release growth factors (GFs) to enhance the tissue healing process. Despite two decades of clinical studies, the therapeutic efficacy of platelet concentrates is still controversial. This work represents a first characterization of a novel autologous leukocyte fibrin platelet membrane (LFPm), which is prepared by the Department of Immunohematology of Belluno Hospital according to a well standardized protocol. The quantification of their specific content showed that LFPms are enriched not only with platelets, but also with monocytes/macrophages, fibrinogen and CD34+ cells. Mechanical properties of LFPms were investigated by tensile tests, revealing that the specific elasticity of membranes was maintained over time. Furthermore, the release kinetics of Platelet Derived Growth Factor, Vascular Endothelial Growth Factor, Tumor Necrosis Factor alpha and Interleukin-10 was assessed by ELISA, demonstrating that LFPms act as GF delivery systems which sustain the local release of bioactive molecules. For in vitro biodegradation analysis, LFPm samples were incubated into PBS solution for 4, 7, 14, 21 days. SEM micrographs showed a progressive loss in cellular elements associated to a simultaneous exposure of the fibrin scaffold, also confirmed by histological and immunohistochemical investigations. In parallel, LFPm disks were implanted into a subcutaneous dorsal pouch of healthy nude rats and explanted after 4, 7, 14, 21 days for in vivo biodegradation study. SEM, histological and immunohistochemical analysis revealed that the typical LFPm fibrin structure was maintained until day 7, with a contemporary loss of cellular elements. From day 14, the morphology and texture of samples became less and less recognizable, confirming that a progressive biodegradation occurred. Overall, collected evidences could support the rationale for the clinical use of LFPms, shading some light on the regenerative effect they may exert after the autologous implant on a defect site

Exploring a tissue engineering strategy as a novel approach for haemophilic arthropathy treatment

Among the most disabling complications of Haemophilia, repeated and sponta- neous intra-articular haemorrhages may cause irreversible damage to the joint. This leads to haemophilic arthropathy, a polyarticular disease characterized by joint stiff- ness, chronic pain and a severely limited range of motion. Occurrence of haemophilic arthropathy can be avoided by the prophylactic administration of clotting factors to prevent articular haemorrhages, but it can also be addressed using anti-inflammatory drugs and surgery to alleviate the effects of articular damage, up to arthroplasty as resolute option [1]. However, innovative strategies for the prevention and treatment of this common and serious complication are still required, due to some important limits of current therapies, first of all inhibitor development. In this work, we inves- tigated a tissue engineering approach to regenerate articular focal lesions in Haemo- philic patients by in vitro development of an autologous bio-hybrid prosthesis. For this purpose, we isolated articular chondrocytes from Haemophilic patients (HaeCs) and characterized them for the first time in literature, to verify whether they were altered by blood exposure. Using healthy chondrocytes as control, optical microscope morphological analysis, flow cytometry immunophenotype evaluation and gene expression study by qRT-PCR were performed. After that, an innovative compos- ite scaffold was obtained by combining decellularized Wharton’s Jelly (W’s J) from human umbilical cord with a novel biodegradable polyvinyl alcohol (PVA) hydrogel [2]. Finally, we assessed HaeCs capacity to re-populate biosynthetic scaffolds by Scan- ning Electron Microscopy and MTT assay on cells seeded on supports. Taken togeth- er, our results contributed to define HaeCs phenotype, highlighting the possibility to use these cells for autologous implant. What is more, HaeCs capacity to growth and proliferate on composite scaffolds set the stage for planning the development of autologous tissue substitutes for haemophilic cartilage regeneration