Ultrasound Stimulation of Piezoelectric Nanocomposite Hydrogels Boosts Chondrogenic Differentiation in Vitro, in Both a Normal and Inflammatory Milieu

The use of piezoelectric nanomaterials combined with ultrasound stimulation is emerging as a promising approach for wirelessly triggering the regeneration of different tissue types. However, it has never been explored for boosting chondrogenesis. Furthermore, the ultrasound stimulation parameters used are often not adequately controlled. In this study, we show that adipose-tissue-derived mesenchymal stromal cells embedded in a nanocomposite hydrogel containing piezoelectric barium titanate nanoparticles and graphene oxide nanoflakes and stimulated with ultrasound waves with precisely controlled parameters (1 MHz and 250 mW/cm2, for 5 min once every 2 days for 10 days) dramatically boost chondrogenic cell commitment in vitro. Moreover, fibrotic and catabolic factors are strongly down-modulated: proteomic analyses reveal that such stimulation influences biological processes involved in cytoskeleton and extracellular matrix organization, collagen fibril organization, and metabolic processes. The optimal stimulation regimen also has a considerable anti-inflammatory effect and keeps its ability to boost chondrogenesis in vitro, even in an inflammatory milieu. An analytical model to predict the voltage generated by piezoelectric nanoparticles invested by ultrasound waves is proposed, together with a computational tool that takes into consideration nanoparticle clustering within the cell vacuoles and predicts the electric field streamline distribution in the cell cytoplasm. The proposed nanocomposite hydrogel shows good injectability and adhesion to the cartilage tissue ex vivo, as well as excellent biocompatibility in vivo, according to ISO 10993. Future perspectives will involve preclinical testing of this paradigm for cartilage regeneration.

Mineralocorticoid Receptor Antagonism Prevents Type 2 Familial Partial Lipodystrophy Brown Adipocyte Dysfunction

Type-2 Familial Partial Lipodystrophy (FPLD2), a rare lipodystrophy caused by LMNA mutations, is characterized by a loss of subcutaneous fat from the trunk and limbs and excess accumulation of adipose tissue in the neck and face. Several studies have reported that the mineralocorticoid receptor (MR) plays an essential role in adipose tissue differentiation and functionality. We previously showed that brown preadipocytes isolated from a FPLD2 patient's neck aberrantly differentiate towards the white lineage. As this condition may be related to MR activation, we suspected altered MR dynamics in FPLD2. Despite cytoplasmic MR localization in control brown adipocytes, retention of MR was observed in FPLD2 brown adipocyte nuclei. Moreover, overexpression of wild-type or mutated prelamin A caused GFP-MR recruitment to the nuclear envelope in HEK293 cells, while drug-induced prelamin A co-localized with endogenous MR in human preadipocytes. Based on in silico analysis and in situ protein ligation assays, we could suggest an interaction between prelamin A and MR, which appears to be inhibited by mineralocorticoid receptor antagonism. Importantly, the MR antagonist spironolactone redirected FPLD2 preadipocyte differentiation towards the brown lineage, avoiding the formation of enlarged and dysmorphic lipid droplets. Finally, beneficial effects on brown adipose tissue activity were observed in an FPLD2 patient undergoing spironolactone treatment. These findings identify MR as a new lamin A interactor and a new player in lamin A-linked lipodystrophies.

Primers for the Adhesion of Gellan Gum-Based Hydrogels to the Cartilage: A Comparative Study

A stable adhesion to the cartilage is a crucial requisite for hydrogels used for cartilage regeneration. Indeed, a weak interface between the tissue and the implanted material may produce a premature detachment and thus the failure of the regeneration processes. Fibrin glue, cellulose nanofibers and catecholamines have been proposed in the state-of-the-art as primers to improve the adhesion. However, no studies focused on a systematic comparison of their performance. This work aims to evaluate the adhesion strength between ex vivo cartilage specimens and polysaccharide hydrogels (gellan gum and methacrylated gellan gum), by applying the mentioned primers as intermediate layer. Results show that the fibrin glue and the cellulose nanofibers improve the adhesion strength, while catecholamines do not guarantee reaching a clinically acceptable value. Stem cells embedded in gellan gum hydrogels reduce the adhesion strength when fibrin glue is used as a primer, being anyhow still sufficient for in vivo applications. This article is protected by copyright. All rights reserved.

Mesenchymal stromal cells from a progressive pseudorheumatoid dysplasia patient show altered osteogenic differentiation

Background

Progressive pseudorheumatoid dysplasia (PPRD) is a rare autosomal recessive non-inflammatory skeletal disease with childhood onset and is characterized by a progressive chondropathy in multiple joints, and skeletal abnormalities. To date, the etiopathological relationship between biological modification occurring in PPRD and genetic mutation remains an open issue, partially due to the limited availability of biological samples obtained from PPRD patients for experimental studies.

Case presentation

We describe the clinical features of a PPRD patient and experimental results obtained from the biological characterization of PPRD mesenchymal stromal cells (MSCs) and osteoblasts (OBs) compared to normal cell populations. Phenotypic profile modifications were found in PPRD compared to normal subjects, essentially ascribed to decreased expression of CD146, osteocalcin (OC) and bone sialoprotein in PPRD MSCs and enhanced CD146, OC and collagen type I expression in PPRD OBs. Gene expression of Dickkopf-1, a master inhibitor of WNT signaling, was remarkably increased in PPRD MSCs compared to normal expression range, whereas PPRD OBs essentially exhibited higher OC gene expression levels. PPRD MSCs failed to efficiently differentiate into mature OBs, so showing a greatly impaired osteogenic potential.

Conclusions

Since all regenerative processes require stem cell reservoirs, compromised functionality of MSCs may lead to an imbalance in bone homeostasis, suggesting a potential role of MSCs in the pathological mechanisms of PPRD caused by WNT1-inducible signaling pathway protein-3 (WISP3) mutations. In consideration of the lack of compounds with proven efficacy in such a rare disease, these data might contribute to better identify new specific and effective therapeutic approaches.

Development and validation of low-intensity pulsed ultrasound systems for highly controlled in vitro cell stimulation

This work aims to describe the development and validation of two low-intensity pulsed ultrasound stimulation systems able to control the dose delivered to the biological target. Transducer characterization was performed in terms of pressure field shape and intensity, for a high-frequency range (500 kHz to 5 MHz) and for a low-frequency value (38 kHz). This allowed defining the distance, on the beam axis, at which biological samples should be placed during stimulation and to exactly know the intensity at the target. Carefully designed retaining systems were developed, for hosting biological samples. Sealing tests proved their impermeability to external contaminants. The assembly/de-assembly time of the systems resulted ~3 min. Time-domain acoustic simulations allowed to precisely estimate the ultrasound beam within the biological sample chamber, thus enabling the possibility to precisely control the pressure to be transmitted to the biological target, by modulating the transducer's input voltage. Biological in vitro tests were also carried out, demonstrating the sterility of the system and the absence of toxic and inflammatory effects on growing cells after multiple immersions in water, over seven days.

Modeling and Fabrication of Silk Fibroin-Gelatin-Based Constructs Using Extrusion-Based Three-Dimensional Bioprinting

Robotic dispensing-based 3D bioprinting represents one of the most powerful technologies to develop hydrogel-based 3D constructs with enormous potential in the field of regenerative medicine. The optimization of hydrogel printing parameters, proper geometry and internal architecture of the constructs, and good cell viability during the bioprinting process are the essential requirements. In this paper, an analytical model based on the hydrogel rheological properties was developed to predict the extruded filament width in order to maximize the printed structure's fidelity to the design. Viscosity data of two natural hydrogels were imputed to a power-law model to extrapolate the filament width. Further, the model data were validated by monitoring the obtained filament width as the output. Shear stress values occurring during the bioprinting process were also estimated. Human mesenchymal stromal cells (hMSCs) were encapsulated in the silk fibroin-gelatin (G)-based hydrogel, and a 3D bioprinting process was performed to produce cell-laden constructs. Live and dead assay allowed estimating the impact of needle shear stress on cell viability after the bioprinting process. Finally, we tested the potential of hMSCs to undergo chondrogenic differentiation by evaluating the cartilaginous extracellular matrix production through immunohistochemical analyses. Overall, the use of the proposed analytical model enables defining the optimal printing parameters to maximize the fabricated constructs' fidelity to design parameters before the process execution, enabling to achieve more controlled and standardized products than classical trial-and-error approaches in the biofabrication of engineered constructs. Employing modeling systems exploiting the rheological properties of the hydrogels might be a valid tool in the future for guaranteeing high cell viability and for optimizing tissue engineering approaches in regenerative medicine applications.

Polysaccharides on gelatin-based hydrogels differently affect chondrogenic differentiation of human mesenchymal stromal cells

Selection of feasible hybrid-hydrogels for best chondrogenic differentiation of human mesenchymal stromal cells (hMSCs) represents an important challenge in cartilage regeneration. In this study, three-dimensional hybrid hydrogels obtained by chemical crosslinking of poly (ethylene glycol) diglycidyl ether (PEGDGE), gelatin (G) without or with chitosan (Ch) or dextran (Dx) polysaccharides were developed. The hydrogels, namely G-PEG, G-PEG-Ch and G-PEG-Dx, were prepared with an innovative, versatile and cell-friendly technique that involves two preparation steps specifically chosen to increase the degree of crosslinking and the physical-mechanical stability of the product: a first homogeneous phase reaction followed by directional freezing, freeze-drying and post-curing. Chondrogenic differentiation of human bone marrow mesenchymal stromal cells (hBM-MSC) was tested on these hydrogels to ascertain whether the presence of different polysaccharides could favor the formation of the native cartilage structure. We demonstrated that the hydrogels exhibited an open pore porous morphology with high interconnectivity and the incorporation of Ch and Dx into the G-PEG common backbone determined a slightly reduced stiffness compared to that of G-PEG hydrogels. We demonstrated that G-PEG-Dx showed a significant increase of its anisotropic characteristic and G-PEG-Ch exhibited higher and faster stress relaxation behavior than the other hydrogels. These characteristics were associated to absence of chondrogenic differentiation on G-PEG-Dx scaffold and good chondrogenic differentiation on G-PEG and G-PEG-Ch. Furthermore, G-PEG-Ch induced the minor collagen proteins and the formation of collagen fibrils with a diameter like native cartilage. This study demonstrated that both anisotropic and stress relaxation characteristics of the hybrid hydrogels were important features directly influencing the chondrogenic differentiation potentiality of hBM-MSC.

Osteoarthritic Milieu Affects Adipose-Derived Mesenchymal Stromal Cells

The objective of this study was to define the effects of osteoarthritic (OA) milieu on good manufactured practice-adipose-derived mesenchymal stromal cells (GMP-ASC) that are commonly utilized in cell therapies. Two different OA milieu: OA synovial fluid (SF) and OA-conditioned medium (CM) from synoviocytes were used to treat GMP-ASC both in normoxia or hypoxia. GMP-ASC were tested for cell migration, proliferation, cytokine receptors expression (CXCR1, CXCR2, CXCR3, CXCR4, CXCR7, CCR1, CCR2, CCR3, CCR5, IL6R), and cytokines (CXCL8/IL8, CXCL10/IP10, CXCL12/SDF-1, CCL2/MCP1, CCL3/MIP1α, CCL4/MIP1β, CCL5/RANTES, IL6) release. Healthy SF was used as controls. We demonstrated that GMP-ASC show an increase in proliferation, migration, and modulation of CXCR1, CXCR3, CCR1, and CCR5 receptors in hypoxic condition. Moreover, GMP-ASC migration increased 15-fold when treated either with OA-SF or OA-CM compared with healthy SF both in normoxia and hypoxia. GMP-ASC treated in both OA milieu showed an increase in CXCR3, CCR3, and IL6R and a decrease in CCR1 and CCR2 receptors. In OA-SF, we detected higher amount of CXCL10/IP10 than in OA-CM, while CCL2/MCP1 and CCL4/MIP1β were higher in OA-CM compared with OA-SF. CXCL10/IP10 was the only chemokine of the OA milieu, which was down-modulated after treatment with GMP-ASC. In conclusion, we demonstrated specific effects of OA milieu on both GMP-ASC proliferation, migration, and cytokine receptor expression that were strictly dependent on the inflammatory and hypoxic environment. The use of characterized OA milieu is crucial to define the therapeutic effect of GMP-ASC and indicates that CXCL10/IP10-CXCR3 axis is partially involved in the GMP-ASC effect on synovial macrophages. © 2019 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 38:336-347, 2020.

Specific concentration of hyaluronan amide derivative induces osteogenic mineralization of human mesenchymal stromal cells: Evidence of RUNX2 and COL1A1 genes modulation

Hyaluronic acid (HA) is an ideal material for tissue regeneration. The aim of this study was to investigate whether a hyaluronan amide derivative (HAD) can enhance the mineralization of human mesenchymal stem cells (hMSCs). Osteogenically induced hMSCs cultured with or without HAD at different concentrations (0.5 mg/ml or 1 mg/ml) were analyzed for mineral matrix deposition, metabolic activity, cellular proliferation, and the expression of 14 osteogenic genes. Unmodified HA (HYAL) was used as control. We demonstrated that only cells treated daily until day 28 with 0.5 mg/ml HAD, but not with 1 mg/ml of HAD and HYAL, showed a significant induction of mineralization at day 14 compared to the osteogenic control group. HAD at both concentrations tested, significantly decreased the expression of the proliferating marker MKI67 at day 2. By contrast, increased metabolic activity was induced only by HYAL from day 14. HAD at both concentrations significantly down modulated SNAI2, DLX5, RUNX2, COL1A1, and IBSP genes, while significantly up regulated COL15A1. The induction of mineralization of 0.5 mg/ml of HAD at day 14 was significantly dependent on a specific modulation of RUNX2 and COL1A1. Our data demonstrate that only 0.5 mg/ml of HAD, but not HYAL, modulated hMSCs osteogenic differentiation, suggesting that the physicochemical features and concentration of HA products could differently affect osteogenic maturation.

Chitosan-based scaffold counteracts hypertrophic and fibrotic markers in chondrogenic differentiated mesenchymal stromal cells

Cartilage tissue engineering remains problematic because no systems are able to induce signals that contribute to native cartilage structure formation. Therefore, we tested the potentiality of gelatin-polyethylene glycol scaffolds containing three different concentrations of chitosan (CH; 0%, 8%, and 16%) on chondrogenic differentiation of human platelet lysate-expanded human bone marrow mesenchymal stromal cells (hBM-MSCs). Typical chondrogenic (SOX9, collagen type 2, and aggrecan), hypertrophic (collagen type 10), and fibrotic (collagen type 1) markers were evaluated at gene and protein level at Days 1, 28, and 48. We demonstrated that 16% CH scaffold had the highest percentage of relaxation with the fastest relaxation rate. In particular, 16% CH scaffold, combined with chondrogenic factor TGFβ3, was more efficient in inducing hBM-MSCs chondrogenic differentiation compared with 0% or 8% scaffolds. Collagen type 2, SOX9, and aggrecan showed the same expression in all scaffolds, whereas collagen types 10 and 1 markers were efficiently down-modulated only in 16% CH. We demonstrated that using human platelet lysate chronically during hBM-MSCs chondrogenic differentiation, the chondrogenic, hypertrophic, and fibrotic markers were significantly decreased. Our data demonstrate that only a high concentration of CH, combined with TGFβ3, creates an environment capable of guiding in vitro hBM-MSCs towards a phenotypically stable chondrogenesis.

Rational Design and Development of Anisotropic and Mechanically Strong Gelatin-Based Stress Relaxing Hydrogels for Osteogenic/Chondrogenic Differentiation

Rational design and development of tailorable simple synthesis process remains a centerpiece of investigational efforts toward engineering advanced hydrogels. In this study, a green and scalable synthesis approach is developed to formulate a set of gelatin-based macroporous hybrid hydrogels. This approach consists of four sequential steps starting from liquid-phase pre-crosslinking/grafting, unidirectional freezing, freeze-drying, and finally post-curing process. The chemical crosslinking mainly involves between epoxy groups of functionalized polyethylene glycol and functional groups of gelatin both in liquid and solid state. Importantly, this approach allows to accommodate different polymers, chitosan or hydroxyethyl cellulose, under identical benign condition. Structural and mechanical anisotropy can be tuned by the selection of polymer constituents. Overall, all hydrogels show suitable structural stability, good swellability, high porosity and pore interconnectivity, and maintenance of mechanical integrity during 3-week-long hydrolytic degradation. Under compression, hydrogels exhibit robust mechanical properties with nonlinear elasticity and stress-relaxation behavior and show no sign of mechanical failure under repeated compression at 50% deformation. Biological experiment with human bone marrow mesenchymal stromal cells (hMSCs) reveals that hydrogels are biocompatible, and their physicomechanical properties are suitable to support cells growth, and osteogenic/chondrogenic differentiation, demonstrating their potential application for bone and cartilage regenerative medicine toward clinically relevant endpoints.

Immunoelectron microscopic localization of Collagen type XV during human mesenchymal stem cells mineralization

Purpose/Aim of the study. Collagen type XV (ColXV) was identified, in our previews studies, as a novel component of bone extracellular matrix. The present study aims to investigate ColXV localization during mineralization of osteodifferentiated human mesenchymal stem cells (hMSCs).

MATERIAL AND METHODS

hMSCs cultured in osteogenic medium have been analyzed at day 14 and 28 for mineral matrix deposition by alizarin red S staining, ultrastructural analysis and ColXV localization by immunogold electron microscopy.

RESULTS

Our data show an intimate association between ColXV and fibrillar components in areas localized far from mineralized nodules.

CONCLUSIONS

We have demonstrated the efficacy of ultrastructural analysis, combined with immunocytochemistry, to establish a temporal and spatial localization of ColXV. This data, added to previous evidences, contribute to validate the negative effects of calcium deposits on ColXV expression.

Adipose stromal cells mediated switching of the pro-inflammatory profile of M1-like macrophages is facilitated by PGE2: in vitro evaluation

OBJECTIVE

To define if adipose mesenchymal stromal cell (ASC) treatment mediated switching of the pro-inflammatory profile of M1-like macrophages as a means to develop a tailored in vitro efficacy/potency test.

DESIGN

We firstly performed immunohistochemical analysis of CD68, CD80 (M1-like) and CD206 (M2-like) macrophages in osteoarthritic (OA) synovial tissue. ASC were co-cultured in contact and in transwell with activated (GM-CSF + IFNγ)-M1 macrophages. We analyzed IL1β, TNFα, IL6, MIP1α/CCL3, S100A8, S100A9, IL10, CD163 and CD206 by qRT-PCR or immunoassays. Prostaglandin E2 (PGE2) blocking experiments were performed using PGE2 receptor antagonist.

RESULTS

In moderate grade OA synovium we did not always find a higher percentage of CD80 with respect to CD206. M1-like-activated macrophage factors IL1β, TNFα, IL6, MIP1α/CCL3, S100A8 and S100A9 were down-modulated both in contact and in transwell by ASC. However, in both systems ASC induced the typical M2-like macrophage markers IL10, CD163 and CD206. Activated-M1-like macrophages pre-treated with PGE2 receptor antagonist failed to decrease secretion of TNFα, IL6 and to increase that of IL10, CD163 and CD206 when co-cultured with ASC confirming a PGE2 specific role.

CONCLUSIONS

We demonstrated that ASC are responsible for the switching of activated-M1-like inflammatory macrophages to a M2-like phenotype, mainly through PGE2. This evidenced that activated-M1-like macrophages may represent a relevant cell model to test the efficacy/potency of ASC and suggests a specific role of ASC as important determinants in therapeutic dampening of synovial inflammation in OA.

Distinctive expression pattern of cystathionine-β-synthase and cystathionine-γ-lyase identifies mesenchymal stromal cells transition to mineralizing osteoblasts

Mesenchymal stromal cells (MSCs) are key players in the repair or regeneration of the damaged bone tissue. However, heterogeneity exists between MSCs derived from different donors in their bone formation ability both in vitro and in vivo. The identification of markers defining MSCs with different functional phenotypes is fundamental to maximize their clinical potential. In our previous in vivo study, impaired expression in MSCs of cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE), the two key enzymes in the catabolic pathway of homocysteine, was associated to decreased bone formation and to the onset of osteoporosis in mice. Here, we investigated whether osteogenic differentiation of human MSCs (hMSCs) modulates the expression of CBS and CSE. The expression of CBS and CSE was also assessed during chondrogenesis to confirm the specificity of their expression during osteogenesis. hMSCs displayed a heterogeneous mineralizing capacity between donors (70% of the samples mineralized, while 30% did not mineralize). Inducible expression of CBS and CSE was found to be associated with a mineralizing phenotype in hMSCs. In particular, up-regulation of CSE was restricted to hMSCs undergoing mineralization. During chondrogenesis, CBS was significantly up-regulated while CSE expression was not affected. Ex-vivo findings confirmed that mature h-osteoblasts (hOBs) show consistently higher expression of CBS and CSE than hMSCs. Our data provide the first evidence that the expression of CBS and CSE in hMSCs closely correlates with the transition of hMSCs toward the osteoblastic phenotype and that CSE may constitute a novel marker of osteogenic differentiation.

Collagen type XV and the 'osteogenic status'

We have previously demonstrated that collagen type XV (ColXV) is a novel bone extracellular matrix (ECM) protein. It is well known that the complex mixture of multiple components present in ECM can help both to maintain stemness or to promote differentiation of stromal cells following change in qualitative characteristics or concentrations. We investigated the possible correlation between ColXV expression and mineral matrix deposition by human mesenchymal stromal cells (hMSCs) with different osteogenic potential and by osteoblasts (hOBs) that are able to grow in culture medium with or without calcium. Analysing the osteogenic process, we have shown that ColXV basal levels are lower in cells less prone to osteo‐induction such as hMSCs from Wharton Jelly (hWJMSCs), compared to hMSCs that are prone to osteo‐induction such as those from the bone marrow (hBMMSCs). In the group of samples identified as ‘mineralized MSCs’, during successful osteogenic induction, ColXV protein continued to be detected at substantial levels until early stage of differentiation, but it significantly decreased and then disappeared at the end of culture when the matrix formed was completely calcified. The possibility to grow hOBs in culture medium without calcium corroborated the results obtained with hMSCs demonstrating that calcium deposits organized in a calcified matrix, and not calcium ‘per se’, negatively affected ColXV expression. As a whole, our data suggest that ColXV may participate in ECM organization in the early‐phases of the osteogenic process and that this is a prerequisite to promote the subsequent deposition of mineral matrix.

From osteoarthritic synovium to synovial-derived cells characterization: synovial macrophages are key effector cells

Background

The aim of the study was to characterize synovial cells from OA synovium with low-grade and moderate-grade synovitis and to define the role of synovial macrophages in cell culture.

Methods

Synovial tissue explants were analyzed for the expression of typical markers of synovial fibroblasts (SF), synovial macrophages (SM) and endothelial cells. Synovial cells at passage 1 (p.1) and 5 (p.5) were analyzed for different phenotypical markers by flow cytometric analysis, inflammatory factors by multiplex immunoassay, anabolic and degradative factors by qRT-PCR. P.1 and p.5 synovial cells as different cell models were co-cultured with adipose stem cells (ASC) to define SM effects.

Results

Synovial tissue showed a higher percentage of CD68 marker in moderate compared with low-grade synovitis. Isolated synovial cells at p.1 were positive to typical markers of SM (CD14, CD16, CD68, CD80 and CD163) and SF (CD55, CD73, CD90, CD105, CD106), whereas p.5 synovial cells were positive only to SF markers and showed a higher percentage of CD55 and CD106. At p.1 synovial cells released a significantly higher amount of all inflammatory (IL6, CXCL8, CCL2, CCL3, CCL5) and some anabolic (IL10) factors than those of p.5. Moreover, p.1 synovial cells also expressed a higher amount of some degradative factors (MMP13, S100A8, S100A9) than p.5 synovial cells. Co-culture experiments showed that the amount of SM in p.1 synovial cells differently induced or down-modulated some of the inflammatory (IL6, CXCL8, CCL2, CCL3, CCL5) and degradative factors (ADAMTS5, MMP13, S100A8, S100A9).

Conclusions

We found that p.1 (mix of SM and SF) and p.5 (only SF) synovial cells represent two cell models that effectively reproduce the low- or moderate-grade synovitis environment. The presence of SM in culture specifically induces the modulation of the different factors analyzed, confirming that SM are key effector cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-0983-4) contains supplementary material, which is available to authorized users.

Age-independent effects of hyaluronan amide derivative and growth hormone on human osteoarthritic chondrocytes

AIM

Increased age is the most prominent risk factor for the initiation and progression of osteoarthritis (OA). The effects of human growth hormone (hGH) combined or not with hyaluronan amide derivative (HAD) were evaluated on human OA chondrocytes, to define their biological action and potentiality in OA treatment.

MATERIAL AND METHODS

Cell viability, metabolic activity, gene expression and factors released were tested at different time points on chondrocytes treated with different concentrations of hGH (0.01-10 μg/ml) alone or in combination with HAD (1 mg/ml).

RESULTS

We found that OA chondrocytes express GH receptor and that the different doses of hGH tested did not affect cell viability, metabolic activity or the expression of collagen type 2, 1, or 10 nor did it induce the release of IGF-1 or FGF-2. Conversely, hGH treatment increased the expression of hyaluronan receptor CD44. HAD combined with hGH reduced metabolic activity, IL6 release and gene expression, but not the suppressor of cytokine signaling 2 (SOCS2), which was significantly induced and translocated into the nucleus. The parameters analyzed, independently of the treatments used proportionally decreased with increasing age of the patients.

CONCLUSIONS

hGH only induced CD44 receptor on OA chondrocytes but did not affect other parameters, such as chondrocytic gene markers or IGF-1 or FGF-2 release. HAD reduced all the effects induced by hGH partially through a significant induction of SOCS2. These data show that GH or HAD treatment does not influence the response of the OA chondrocytes, thus the modulation of cellular response is age-independent.

Lack of anti-inflammatory and anti-catabolic effects on basal inflamed osteoarthritic chondrocytes or synoviocytes by adipose stem cell-conditioned medium

OBJECTIVE

To define whether good manufacturing practice (GMP)-clinical grade adipose stem cell (ASC)-derived conditioned medium (CM) is as effective as GMP-ASC in modulating inflammatory and catabolic factors released by both osteoarthritis (OA) chondrocytes or synoviocytes.

METHODS

OA chondrocytes and synoviocytes were treated with ASC-CM or co-cultured with ASC. Inflammatory factors (IL6, CXCL1/GROα,CXCL8/IL8, CCL2/MCP-1, CCL3/MIP-1α and CCL5/RANTES) and proteinases, such as metalloproteinase (MMP13), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS4, ADAMTS5) and their tissue metalloproteinase inhibitors (TIMP1, TIMP3) were evaluated by qRT-PCR or immunoassays. The involvement of prostaglandin E2 (PGE2) was also analyzed.

RESULTS

Most ASC-CM ratios tested did not decrease IL6, CCL2/MCP-1, CCL3/MIP1-α, CCL5/RANTES on basal inflamed chondrocytes or synoviocytes in contrast to what we found using ASC in co-culture. CXCL8/IL8 and CXCL1/GROα were not decreased by ASC-CM on synoviocytes but were only partially reduced on chondrocytes. Moreover, ASC-CM was less efficient both on basal inflamed OA chondrocytes and synoviocytes in reducing proteinases, such as MMP13, ADAMTS4, ADAMTS5 and increasing TIMP1 and TIMP3 compared to ASC in co-culture. The different ratios of ASC-CM contain lower amounts of PGE2 which were not sufficient to reduce inflammatory factors.

CONCLUSIONS

These data show that ASC-CM has a limited ability to decrease inflammatory and proteinases factors produced by OA chondrocytes or synoviocytes. ASC-CM is not sufficient to recapitulate the beneficial effect demonstrated using ASC in co-culture with inflamed OA chondrocytes and synoviocytes and shows that their use in clinical trials is fundamental to counteract OA progression.

Slug transcription factor and nuclear Lamin B1 are upregulated in osteoarthritic chondrocytes

OBJECTIVE

To contribute to clarify molecular mechanisms supporting senescence and de-differentiation of chondrocytes in chondrocyte pathologies such as osteoarthritis (OA). Specifically, we investigated the relationship between the nuclear lamina protein Lamin B1 and the negative regulator of chondrogenesis Slug transcription factor in osteoarthritic chondrocytes.

METHODS

Lamin B1 and Slug proteins were analyzed in cartilage explants from normal subjects and OA patients by immunohistochemical technique. Their expression was confirmed on isolated chondrocytes both at passage 0 and passage 2 (de-differentiated chondrocytes) by immunofluorescence and western blot. Subsequently, we explored the "in vivo" binding of Slug on LMNB1 promoter by chromatin immunoprecipitation assay (ChIP).

RESULTS

In this study we demonstrated that nuclear lamina protein Lamin B1 and anti-chondrogenic Slug transcription factor are upregulated in cartilage and OA chondrocytes. Furthermore, we found that Slug is "in vivo" recruited by LMNB1 gene promoter mostly when chondrocytes undergo de-differentiation or OA degeneration.

CONCLUSIONS

We described for the first time a potential regulatory role of Slug on the LMNB1 gene expression in OA chondrocytes. These findings may have important implications for the study of premature senescence, and degeneration of cartilage, and may contribute to develop effective therapeutic strategies against signals supporting cartilage damage in different subsets of patients.

Chondrogenic potential of Slug-depleted human mesenchymal stem cells

The use of short interfering RNA (siRNA) in combination with stem cells and biocompatible scaffolds is a promising strategy in regenerative medicine. Our experimental strategy was to explore the possibility of forcing or guiding the chondrogenic differentiation of human mesenchymal stem cells (hMSCs) by knocking down a negative regulator of chondrogenesis, Slug transcription factor (TF), thus altering cell behavior. We found that TGFβ-driven chondrogenic differentiation of hMSCs cultured onto a hyaluronan-based scaffold, HYAFF(®)-11, was strengthened after cell exposure to siRNA against Slug. Slug silencing was effective in promoting the expression of chondrogenic markers, including Col2A1, aggrecan, Sox9, LEF1, and TRPS1. In addition, we confirmed that HYAFF-11 is a good scaffold candidate for hMSC use in tissue engineering applications, and showed that it is effective in sustaining TGFβ3 treatment associated with a specific gene silencing. Interestingly, preliminary results from the experimental model described here suggested that, even in the absence of differentiation supplements, Slug silencing showed a pro-chondrogenic effect, highlighting both its potential use as an alternative to TGFβ treatment, and the critical role of the Slug TF in determining the fate of hMSCs.

Adipose-derived mesenchymal stem cells exert antiinflammatory effects on chondrocytes and synoviocytes from osteoarthritis patients through prostaglandin E2

OBJECTIVE

To examine the effect of different sources of good manufacturing practice clinical grade adipose-derived mesenchymal stem cells (AD-MSCs) on inflammatory factors in osteoarthritic (OA) chondrocytes and synoviocytes.

METHODS

AD-MSCs from infrapatellar Hoffa fat, subcutaneous (SC) hip fat, and SC abdominal fat were cocultured in Transwells with chondrocytes or synoviocytes. Inflammatory factors (interleukin-1β [IL-1β], tumor necrosis factor α, IL-6, CXCL1/growth-related oncogene α, CXCL8/IL-8, CCL2/monocyte chemotactic protein 1, CCL3/macrophage inflammatory protein 1α, and CCL5/RANTES) were evaluated by quantitative reverse transcription-polymerase chain reaction or multiplex bead-based immunoassay. The role of different immunomodulators was analyzed.

RESULTS

All the inflammatory factors analyzed were down-modulated at the messenger RNA or protein level independently by all 3 AD-MSC sources or by allogeneic AD-MSCs used in coculture with chondrocytes or synoviocytes. Inflammatory factor down-modulation was observed only when AD-MSCs were cocultured with chondrocytes or synoviocytes that produced high levels of inflammatory factors, but no effect was observed in cells that produced low levels of those factors, thus highlighting a dependence of the AD-MSC effect on existing inflammation. The immunomodulators IL-10, IL-1 receptor antagonist, fibroblast growth factor 2, indoleamine 2,3-dioxygenase 1, and galectin 1 were not involved in AD-MSC effects, whereas the cyclooxygenase 2 (COX-2)/prostaglandin E2 (PGE2 ) pathway exerted a role in the mechanism of antiinflammatory AD-MSC action.

CONCLUSION

The antiinflammatory effects of AD-MSCs are probably not dependent on AD-MSC adipose tissue sources and donors but rather on the inflammatory status of OA chondrocytes and synoviocytes. AD-MSCs seem to be able to sense and respond to the local environment. Even though a combination of different molecules may be involved in AD-MSC effects, the COX-2/PGE2 pathway may play a role, suggesting that AD-MSCs may be useful for therapies in osteoarticular diseases.

Adipose mesenchymal stem cells protect chondrocytes from degeneration associated with osteoarthritis

Our work aimed at evaluating the role of adipose stem cells (ASC) on chondrocytes from osteoarthritic (OA) patients and identifying the mediators involved. We used primary chondrocytes, ASCs from different sources and bone marrow mesenchymal stromal cells (MSC) from OA donors. ASCs or MSCs were co-cultured with chondrocytes in a minimal medium and using cell culture inserts. Under these conditions, ASCs did not affect the proliferation of chondrocytes but significantly decreased camptothecin-induced apoptosis. Both MSCs and ASCs from different sources allowed chondrocytes in the cocultures maintaining a stable expression of markers specific for a mature phenotype, while expression of hypertrophic and fibrotic markers was decreased. A number of factors known to regulate the chondrocyte phenotype (IL-1β, IL-1RA, TNF-α) and matrix remodeling (TIMP-1 and -2, MMP-1 and -9, TSP-1) were not affected. However, a significant decrease of TGF-β1 secretion by chondrocytes and induction of HGF secretion by ASCs was observed. Addition of a neutralizing anti-HGF antibody reversed the anti-fibrotic effect of ASCs whereas hypertrophic markers were not modulated. In summary, ASCs are an interesting source of stem cells for efficiently reducing hypertrophy and dedifferentiation of chondrocytes, at least partly via the secretion of HGF. This supports the interest of using these cells in therapies for osteo-articular diseases.

T cell subsets differently regulate osteogenic differentiation of human mesenchymal stromal cells in vitro

T lymphocytes play a key role in the regulation of bone homeostasis and bone healing. The inflammatory response at the site of bone injury is essential to the initiation of the bone repair program; however, an uncontrolled exposure to inflammatory environment has a negative effect on tissue regeneration - indeed, activated T cells were shown to inhibit osteogenic differentiation on human mesenchymal stromal cells (MSCs). Whether resting T cells can induce osteogenic differentiation of MSCs and what role specific T cells subset play in this process is still elusive. In this study, we sought to analyse the osteogenic gene expression profile of whole T cells, CD4 and CD8 T cells isolated from healthy donors and investigated whether secreted factors from each group modulate osteogenic differentiation of human MSCs. Gene expression profiling identified a pool of 51 genes involved at various stages in bone growth which are expressed above detectable levels in CD4 and CD8 T cells. Most genes of this pool were expressed at higher levels in the CD4 subset. In vitro mineralization assays revealed that conditioned medium from CD4 T cells, but not from CD8 cells, significantly increased mineralization in osteogenic cultures of human MSCs; furthermore, mRNA expression of Runt-related transcription factor 2 (RUNX-2), osteocalcin (OC), bone sialoprotein (BSP) and alkaline phosphatase (ALP) in MSCs was significantly upregulated in the presence of CD4-conditioned medium but not with that obtained from CD8. The results show a differential role for CD4 and CD8 T cells in supporting bone formation and identify an osteogenic gene signature of each subset.

Specific inductive potential of a novel nanocomposite biomimetic biomaterial for osteochondral tissue regeneration

Osteochondral lesions require treatment to restore the biology and functionality of the joint. A novel nanostructured biomimetic gradient scaffold was developed to mimic the biochemical and biophysical properties of the different layers of native osteochondral structure. The present results show that the scaffold presents important physicochemical characteristics and can support the growth and differentiation of mesenchymal stromal cells (h-MSCs), which adhere and penetrate into the cartilaginous and bony layers. H-MSCs grown in chondrogenic or osteogenic medium decreased their proliferation during days 14-52 on both scaffold layers and in medium without inducing factors used as controls. Both chondrogenic and osteogenic differentiation of h-MSCs occurred from day 28 and were increased on day 52, but not in the control medium. Safranin O staining and collagen type II and proteoglycans immunostaining confirmed that chondrogenic differentiation was specifically induced only in the cartilaginous layer. Conversely, von Kossa staining, osteocalcin and osteopontin immunostaining confirmed that osteogenic differentiation occurred on both layers. This study shows the specific potential of each layer of the biomimetic scaffold to induce chondrogenic or osteogenic differentiation of h-MSCs. These processes depended mainly on the media used but not the biomaterial itself, suggesting that the local milieu is fundamental for guiding cell differentiation. Copyright © 2013 John Wiley & Sons, Ltd.

Role of Slug transcription factor in human mesenchymal stem cells

The pathways that control mesenchymal stem cells (MSCs) differentiation are not well understood, and although some of the involved transcription factors (TFs) have been characterized, the role of others remains unclear. We used human MSCs from tibial plateau (TP) trabecular bone, iliac crest (IC) bone marrow and Wharton’s jelly (WJ) umbilical cord demonstrating a variability in their mineral matrix deposition, and in the expression levels of TFs including Runx2, Sox9, Sox5, Sox6, STAT1 and Slug, all involved in the control of osteochondroprogenitors differentiation program. Because we reasoned that the basal expression level of some TFs with crucial role in the control of MSC fate may be correlated with osteogenic potential, we considered the possibility to affect the hMSCs behaviour by using gene silencing approach without exposing cells to induction media. In this study we found that Slug-silenced cells changed in morphology, decreased in their migration ability, increased Sox9 and Sox5 and decreased Sox6 and STAT1 expression. On the contrary, the effect of Slug depletion on Runx2 was influenced by cell type. Interestingly, we demonstrated a direct in vivo regulatory action of Slug by chromatin immunoprecipitation, showing a specific recruitment of this TF in the promoter of Runx2 and Sox9 genes. As a whole, our findings have important potential implication on bone tissue engineering applications, reinforcing the concept that manipulation of specific TF expression levels may elucidate MSC biology and the molecular mechanisms, which promote osteogenic differentiation.

Extracellular calcium chronically induced human osteoblasts effects: specific modulation of osteocalcin and collagen type XV

Fluctuation in extracellular calcium (Ca(2+)) concentration occurs during bone remodeling. Free ionized Ca(2+) plays a critical role in regulating osteoblast functions. We analyzed the effects of different concentrations of free ionized Ca(2+) (0.5, 1.3, and 2.6 mM) on human osteoblasts and we evaluated osteoblastic phenotype (marker expression and cell morphology) and functions (osteogenic differentiation, cell proliferation, and cell signaling). Our data show human osteoblasts that chronically stimulated with 0.5, 1.3, or 2.6 mM Ca(2+) significantly increase intracellular content of alkaline phosphatase, collagen type I, osteocalcin, and bone sialoprotein, whereas collagen type XV was down-modulated and RUNX2 expression was not affected. We also found a Ca(2+) concentration-dependent increase in osteogenic differentiation and cell proliferation, associated to an increase of signaling protein PLCβ1 and p-ERK. Human osteoblast morphology was affected by Ca(2+) as seen by the presence of numerous nucleoli, cells in mitosis, cell junctions, and an increased number of vacuoles. In conclusion, our data show a clear phenotypical and functional effect of extracellular Ca(2+) on human osteoblasts and support the hypothesis of a direct role of this cation in the bone remodeling processes.

Transcription factor decoy against NFATc1 in human primary osteoblasts

The present study describes, for the first time, the removal of the nuclear factor of activated T cells cytoplasmic 1 (NFATc1) by a decoy approach in human primary osteoblasts (hOBs). hOBs with different NFATc1 expression levels were used. The functionality of endogenous NFAT proteins in our experimental model was analyzed by monitoring the transcriptional activity on a luciferase reporter construct driven by three copies of an NFAT response element (pNFAT-TA-luc). Cell treatment with the decoy against NFATc1 resulted in a significant increase in the expression of osteoblastic markers, including ERα and ColXV. On the contrary, the expression of Runx2, which is known to not be transcriptionally regulated by NFATc1, was not altered, indicating the specificity of the decoy effect. To our knowledge, this is the first time that transcription factor decoy has been successful in hOBs to allow the investigation of the role of NFATc1 in an experimental model that, compared to the use of cell lines, more closely resembles an in vivo model. In addition, by using chromatin immunoprecipitation we found that in vivo NFATc1 is recruited on the ColXV gene promoter. The specific role of NFATc1 in osteoblast differentiation is not well understood, however, our findings reinforce the action of NFATc1 in the transcriptional program of osteoblasts, also supporting the therapeutic potential for the proper manipulation of NFATc1-mediated events in different bone disorders. At the same time, our data add important information on the regulation of the expression of ColXV, which only recently has been proposed as an osteoblastic marker.

Chemical-physical properties and in vitro cell culturing of a novel biphasic bio-mimetic scaffold for osteo-chondral tissue regeneration

The requirements for a successful regeneration of an osteo-chondral defect could effectively be met by using a bi-layered composite scaffold, able to support proliferation and differentiation of mesenchymal stem cells, while providing a biochemical environment promoting the formations of the two distinct tissues. The novel strategy here presented consists of developing a bio-mimetic scaffolds obtained by the combination of two integrated organic compounds (type I collagen and chitosan) with or without bioactive Mg-doped hydroxyapatite (Mg-HA) nanocrystals, depending on the specific layer, reproducing cartilaginous or subchondral bone tissue. An innovative patented methodology for scaffolds production, called - pH-dependent 3-phasic assembling -, allowed to development of a highly homogenous and chemically stable scaffold, presenting a very good integration among all three components, as confirmed by extensive SEM and thermogravimetric analyses. A preliminary in vitro evaluation was also carried out by seeding bi-layered scaffold with human bone marrow stromal cells (h-MSCs), by giving particular emphasis to cell viability and distribution at day 0, 7 and 14. Cells were viable and uniformly colonized the whole scaffold until day 14, indicating that the scaffold contributed to the maintenance of cell behaviour.

Slug gene expression supports human osteoblast maturation

This study aims to define the function of Slug transcription factor in human normal osteoblasts (hOBs). To date, Slug is considered exclusively a marker of malignancy in bone tissue. Here, we identified, for the first time, a role for Slug in hOBs using a knockdown approach. We demonstrated that Slug is positively correlated with osteoblast markers, including Runx2, osteopontin, osteocalcin, Collagen type 1, Wnt/beta-catenin signaling mediators, and mineral deposition. At the same time, Slug silencing potentiates the expression of Sox-9, a factor indispensable for chondrogenic development. These data, with the finding that Slug is in vivo recruited by the promoters of Runx2 and Sox-9 genes, suggest that, in hOBs, Slug may act both as positive and negative transcriptional regulator of Runx2 and Sox-9 genes, respectively. In summary, our results support the hypothesis that Slug functions as a novel regulator of osteoblast activity and may be considered a new factor required for osteoblast maturation.

Diagnostic role of circulating free plasma DNA detection in patients with localized prostate cancer

To analyze the potential diagnostic relevance of free plasma DNA (FPDNA), we enrolled 64 patients with localized prostate cancer (CaP). FPDNA was quantified by real-time polymerase chain reaction assessment of the HTERT gene in blood samples from 64 patients with CaP and 45 healthy males. Methylation of the GSTP1 gene was used to confirm the neoplastic origin of FPDNA in selected cases. The mean +/- SD levels of FPDNA were higher in patients with CaP (15.4 +/- 10.9 ng/mL) than in control subjects (5.5 +/- 3.5 ng/mL; P <.001). By using the best cutoff value, the sensitivity of the test was 80%, the specificity was 82%, the area under the receiver operating characteristic curve, 0.881. High FPDNA values were significantly associated with pathologic T3 stage (P = . 035). Methylation of the GSTP1 gene was found in 4 (25%) of 16 FPDNA samples and 15 (94%) of 16 tissue samples. Quantification of FPDNA discriminates between patients with CaP and healthy subjects and correlates with pathologic tumor stage. FPDNA is a candidate biomarker for early diagnosis and monitoring of CaP.

Two Years’ Experience of Acute Rejection Monitoring of Intestinal Transplant Recipients by Real-Time PCR Assessment of Granzyme B and Perforin Up-Regulation: Considerations on Diagnostic Accuracy

Granzyme B (GrB) and perforin are promising immunological markers to predict acute rejection of transplanted organs. Based on 2 years of experience with molecular monitoring on peripheral blood samples, we investigated the diagnostic accuracy of GrB/perforin gene up-regulation using real-time polymerase chain reaction (PCR) for prediction of acute cellular rejection (ACR) in intestinal transplantation recipients. Histology used as the reference standard. According to our definition of disease positivity (anything other than ACR score 0), GrB/perforin up-regulation showed 84% specificity but only 49% sensitivity. However, among the 26 false-negatives, 12 (46%) had an ACR score 1, which is indeterminate for rejection and no associated clinical manifestations; a further 10 (39%) had a score of 2 following rejection therapy (a confounder for GrB/perforin analysis). Thus only 4 (15%) false-negatives were actually associated with the onset of robust acute rejection. These data suggest that real-time PCR analysis for GrB/perforin up-regulation might play a role along with clinical criteria for detection of presymptomatic acute rejection episodes in intestinal recipients who require immediate endoscopy and pathological examination, especially during long-term follow-up.

Potential of Real-Time PCR Assessment of Granzyme B and Perforin Up-Regulation for Rejection Monitoring in Intestinal Transplant Recipients

Granzyme B (GrB) and perforin are promising markers to predict acute rejection episodes of transplanted organs. Having recently reported that immunohistochemical expression of GrB/perforin correlates with histologically assessed acute cellular rejection (ACR) episodes in intestinal transplantation recipients, herein we have additionally explored the potential of real-time polymerase chain reaction (PCR) assessment of GrB/perforin gene up-regulation in peripheral blood mononuclear cells. Both immunohistochemical evaluation of GrB/perforin expression and real-time PCR assessment of up-regulation, which was defined as a 2-fold increase with respect to "basal" levels during maintenance immunosuppressive protocols, were performed among a population of 23 intestinal transplant recipients under routine surveillance, in addition to histological analysis of ACR. The ACR scores showed direct relationships both with GrB/perforin immunohistochemistry (IHC) scores (P < .001) and with gene up-regulation by real-time PCR (P = .004). Furthermore, real-time PCR upregulation was associated with the IHC score (P < .001). A preliminary analysis of diagnostic accuracy-performed to gain information to plan future studies-indicated that when using histological assessment as the reference technique, our current definition of PCR up-regulation provided good specificity (84%) but insufficient sensitivity (44%) for a noninvasive prediction of ACR. The results of this pilot study suggested that real-time PCR analysis of GrB/perforin upregulation may help therapeutic decision making, and have the potential for detection of presymptomatic rejection. More extensive studies must investigate strategies to improve the sensitivity of the analyses of GrB/perforin up-regulation.

Application of a fluorescent PCR method for molecular diagnosis of posttransplant lymphoproliferative disorders on routine tissue sections

Molecular detection of monoclonality can play an important role in the diagnosis of posttransplantation lymphoproliferative disorders (PTLD). To permit accurate molecular diagnosis of PTLD even on very small amounts of DNA extracted from routinely embedded histologic material, we adapted a commercially available PCR protocol (for FR-1, -2 and -3 regions), originally designed for use on fresh/frozen samples. We applied this approach on routine biopsy/surgical material of 10 PTLD (from nine patients). All three FR regions were always amplified, indicating that the extracted DNA was of medium quality. All five PTLD morphologically classified as lymphomas were monoclonal in at least one FR region. Thus, using the WHO histologic, immunohistochemical, and clinical criteria as the reference standard, the approach provided 100% sensitivity for detection of monoclonal malignancies, supporting the validity of the method. Of five specimens classified morphologically as polymorphic PTLD, three displayed a solitary IgH gene rearrangement peak, consistent with the presence of a monoclonal B-cell population (ie, monoclonal polymorphic PTLD). This rapid and straightforward procedure, which allows identification of a wide range of IgH rearrangements, could facilitate molecular analysis of PTLD in routine practice, while limiting consumption of valuable diagnostic material.

Molecular monitoring of organ recipients from cancer-affected donors by detection of circulating tumor cells

We have initiated regular molecular monitoring based on nested RT-PCR detection of circulating tumor cells for monitoring recipients of organs from cancer-affected donors in Italy (in the context of a "Donation Safety and Donated Organ Quality" project organized by the Centro Nazionale Trapianti). Five patients are being monitored. For two patients who each received a kidney from a single donor with prostate adenocarcinoma, RT-PCR was performed using PSA mRNA. For three recipients of organs (two livers and one kidney) from donors with renal cell carcinoma, RT-PCR was performed using cytokeratine 18 and 19 mRNA. Blood samples from five healthy subjects were used as negative controls. After a median monitoring time of 26 months (range 8 to 32), none of the regular 3-month assays has tested positive. This pilot study suggests that detection of circulating tumor cells by nested RT-PCR may provide a feasible molecular monitoring, which might assist decision making regarding other forms of clinical surveillance.

Predictive value of biological markers for hepatocellular carcinoma patients treated with orthotopic liver transplantation

PURPOSE

To help stratify candidates with hepatocellular carcinoma (HCC) for orthotopic liver transplantation (OLT), biomarkers are needed that are capable of predicting recurrence of disease (ROD). We investigated the prognostic role in this setting of immunohistochemical markers reported previously to predict poor prognosis in HCC patients treated with resection.

EXPERIMENTAL DESIGN

Eighty-three patients with HCC who underwent OLT between 1987 and 2001 with a minimum clinical follow up of 12 months were included in this retrospective study. We analyzed immunohistochemical expression of the adhesion molecules E-cadherin and beta-catenin (membrane/nuclear localization), MIB-1 proliferative index and the cyclin-dependent kinase inhibitor p27, alongside the main clinical-pathological variables.

RESULTS

At univariate analysis, vascular thrombosis, high MIB-1 index, lower membrane expression of E-cadherin and beta-catenin, and nuclear beta-catenin localization were associated with ROD. At multivariate analysis, only MIB-1 index, low equal E-cadherin (with respect to non-neoplastic surrounding tissue), and nuclear beta-catenin appeared as independent predictors of ROD. The logistic regression analysis model indicated that detection of any one parameter was associated with at least 88% estimated risk of ROD (up to 99% for all three).

CONCLUSIONS

We propose these three molecular parameters as an additional tool for rational selection of OLT candidates among HCC patients (stratification according to the risk of ROD might help provide a similar life expectancy for cirrhotic candidates with and without HCC).

Granzyme B and perforin as predictive markers for acute rejection in human intestinal transplantation

In human heart and kidney transplantations, granzyme B (GrB) and perforin have both been shown to be predictive markers for acute cellular rejection (ACR). We investigated the tissue expression and possible relationship of GrB and perforin to the clinical outcome, histopathology, and function of intestinal transplants. In 13 consecutive patients undergoing small intestine transplantation, histologic/immunohistochemical rejection monitoring was performed together with GrB and perforin immunostaining (score "0", 0%-10% positive lymphocytes; "1", 10%-25%; "2", 25%-50%; "3", >50%). Eleven patients are currently alive and well. All 11 had at least one episode of ACR: one patient had 6 episodes of severe ACR requiring retransplantation; the remaining 10 experienced only mild or moderate rejection. Both GrB and perforin were always co-expressed. A highly significant correlation was observed between GrB/perforin scores and histological severity of ACR (Pearson's coefficient, R < 0.0009). Interestingly, score 3 GrB/perforin immunostaining was recorded only in the context of severe ACR; all the histologically negative or "indeterminate" biopsies (n = 6) taken from a single affected patient showed GrB/perforin scores of 1 or 2. By contrast, none of the other tested histologically negative/"indeterminate" biopsies (n = 350), including those performed during graft stabilization, had raised GrB or perforin scores. We conclude that in intestinal transplantation recipients, a direct correlation seems to exist between histologically confirmed ACR and raised GrB/perforin immunohistochemical scores. Our findings suggest the need to investigate the possibility of predicting ACR by routine serum polymerase chain reaction (PCR) monitoring, which would reduce discomfort to patients.

Detection of the M30 neoepitope as a new tool to quantify liver apoptosis: timing and patterns of positivity on frozen and paraffin-embedded sections

One of the first stages of apoptosis is cytokeratin cleavage mediated by caspases, which is associated with the expression of a neoepitope, the cleavage site of cytokeratin 18, identifiable by the M30 monoclonal antibody. The aim of this study was to evaluate the timing of neoantigen expression and its modifications in the various morphologic stages of apoptosis on frozen and paraffin-embedded sections from liver biopsies of patients with chronic hepatitis or transplanted liver. The appearance of this neoepitope coincides with the gradual disappearance of cytokeratins, with the appearance of nuclear DNA fragmentation, and with the presence of Councilman bodies. The staining patterns on paraffin-embedded sections of liver specimens were similar to those found in frozen sections, with a reduced sensitivity. The M30 antibody is correlated with apoptosis, and its specificity for epithelial cells makes this method the first choice for routine evaluation of apoptosis in liver epithelial cells.

Detection of the M30 neoepitope as a new tool to quantify liver apoptosis: timing and patterns of positivity on frozen and paraffin-embedded sections

One of the first stages of apoptosis is cytokeratin cleavage mediated by caspases, which is associated with the expression of a neoepitope, the cleavage site of cytokeratin 18, identifiable by the M30 monoclonal antibody. The aim of this study was to evaluate the timing of neoantigen expression and its modifications in the various morphologic stages of apoptosis on frozen and paraffin-embedded sections from liver biopsies of patients with chronic hepatitis or transplanted liver. The appearance of this neoepitope coincides with the gradual disappearance of cytokeratins, with the appearance of nuclear DNA fragmentation, and with the presence of Councilman bodies. The staining patterns on paraffin-embedded sections of liver specimens were similar to those found in frozen sections, with a reduced sensitivity. The M30 antibody is correlated with apoptosis, and its specificity for epithelial cells makes this method the first choice for routine evaluation of apoptosis in liver epithelial cells.

Thorough intraoperative analysis of breast sentinel lymph node biopsies: histologic and immunohistochemical findings

BACKGROUND

We report the use of a thorough intraoperative sentinel lymph node (SLN) biopsy screening procedure for patients with small N0 breast tumors.

METHODS

Sixty-eight consecutive female patients with monofocal stage I or "small" stage II (ie, 2.1-3.0 cm) N0 tumors received intraoperative SLN screening according to a procedure on the basis of comprehensive histologic analysis and cytokeratin immunohistochemical determination (CkID) of adjacent frozen sections of the SLN taken at 50-microm cutting levels.

RESULTS

The maximum duration of intraoperative analysis including CkID was 40 minutes. Positive SLN were found in 15/68 (22%) patients (always in a single node); they included 5 instances of micrometastasis and 3 of carcinomatous lymphangitis. In the 14 patients who underwent axillary lymph node dissection, no further metastasis was found at histologic analysis or CkID. SLN positivity correlated with histologic type (P=.044), intratumoral or peritumoral vascular invasion (P<.001) and Mib1 score (P=.042).

CONCLUSIONS

It is possible for an experienced team to perform intraoperative SLN screening for T1 or small T2 N0 breast tumors with frozen sections taken at 50-microm cutting levels. This procedure facilitates identification of micrometastasis, as well as of carcinomatous lymphangitis to help understand the biologic implications of these small lesions in the long term. SLN positivity appears to correlate with histologic type, intratumoral/peritumoral vascular invasion and Mib1 score.