Xeno-free cultured mesenchymal stromal cells release extracellular vesicles with a "therapeutic" miRNA cargo ameliorating cartilage inflammation in vitro.

Rationale: Mesenchymal stromal cells (MSCs)-derived extracellular vesicles (EVs) emerged as an innovative strategy for the treatment of chronic disorders such as osteoarthritis (OA). Biological activity of EVs is generally driven by their cargo, which might be influenced by microenvironment. Therefore, pre-conditioning strategies, including modifications in culture conditions or oxygen tension could directly impact on MSCs paracrine activity. In this study we selected an appropriate preconditioning system to induce cells to perform the most suitable therapeutic response by EV-encapsulated bioactive factors. Methods: A xeno-free supplement (XFS) was used for isolation and expansion of MSCs and compared to conventional fetal bovine serum (FBS) culture. Bone Marrow-derived MSCs (BMSCs) were pre-conditioned under normoxia (20% O2) or under hypoxia (1% O2) and EVs production was evaluated. Anti-OA activity was evaluated by using an in vitro inflammatory model. miRNA content was also explored, to select putative miRNA that could be involved in a biological function. Results: Modulation of IL-6, IL-8, COX-2 and PGE2 was evaluated on hACs simultaneously treated with IL-1α and BMSC-derived EVs. FBS-sEVs exerted a blunt inhibitory effect, while a strong anti-inflammatory outcome was achieved by XFS-sEVs. Interestingly, in both cases hypoxia pre-conditioning allowed to increase EVs effectiveness. Analysis of miRNA content showed the upregulation in XFS-hBMSC-derived EVs of miRNA known to have a chondroprotective role, such as let-7b-5p, miR-17, miR-145, miR-21-5p, miR-214-3p, miR-30b-5p, miR-30c-5p. Activated pathways and target genes were investigated in silico and upregulated miRNAs functionally validated in target cells. MiR-145 and miR-214 were found to protect chondrocytes from IL-1α-induced inflammation and to reduce production of pro-inflammatory cytokines. Conclusions: XFS medium was found to be suitable for isolation and expansion of MSCs, secreting EVs with a therapeutic cargo. The application of cells cultured exclusively in XFS overcomes issues of safety associated with serum-containing media and makes ready-to-use clinical therapies more accessible.

Prognostic Role of Soluble and Extracellular Vesicle-Associated PD-L1, B7-H3 and B7-H4 in Non-Small Cell Lung Cancer Patients Treated with Immune Checkpoint Inhibitors.

The treatment of non-small cell lung cancer (NSCLC) has changed dramatically with the advent of immune checkpoint inhibitors (ICIs). Despite encouraging results, their efficacy remains limited to a subgroup of patients. Circulating immune checkpoints in soluble (s) form and associated with extracellular vesicles (EVs) represent promising markers, especially in ICI-based therapeutic settings. We evaluated the prognostic role of PD-L1 and of two B7 family members (B7-H3, B7-H4), both soluble and EV-associated, in a cohort of advanced NSCLC patients treated with first- (n = 56) or second-line (n = 126) ICIs. In treatment-naïve patients, high baseline concentrations of sPD-L1 (>24.2 pg/mL) were linked to worse survival, whereas high levels of sB7-H3 (>0.5 ng/mL) and sB7-H4 (>63.9 pg/mL) were associated with better outcomes. EV characterization confirmed the presence of EVs positive for PD-L1 and B7-H3, while only a small portion of EVs expressed B7-H4. The comparison between biomarker levels at the baseline and in the first radiological assessment under ICI-based treatment showed a significant decrease in EV-PD-L1 and an increase in EV-B7H3 in patients in the disease response to ICIs. Our study shows that sPD-L1, sB7-H3 and sB7-H4 levels are emerging prognostic markers in patients with advanced NSCLC treated with ICIs and suggests potential EV involvement in the disease response to ICIs.

Pilot study investigating BP-180 in extracellular vesicles derived from blister fluid of bullous pemphigoid patients.

Bullous pemphigoid (BP) is an autoimmune blistering disease that targets the haemidesmosomal proteins, mainly BP180. Extracellular vesicles (EVs) have been demonstrated to carry tissue-specific autoantigens in the setting of autoimmune diseases and transplant organ rejection; this phenomenon was demonstrated to have pathogenic implications in autoimmune diseases and to correlate with transplant rejection severity. The purpose of this study was to identify the presence of BP targeted autoantigens in blister fluid derived EVs. We isolated, by size exclusion chromatography, EVs derived from blisters of BP-patients and from suction blisters of healthy donors. EV characterization was performed by flow cytometry and nanoparticle tracking analysis. Western blot analysis was used to investigate the presence of autoantigens. A suspension enriched in EVs was efficiently obtained from blister fluid from patients and healthy donors. EV-enriched fractions were enriched in particles with a size distribution characterizing small-EVs (main peak was present at 94.5 nm). BP180 was found, by western blot analysis, in EVs derived from blister fluid of 3 out 6 BP patients and in none of EVs isolated from suction blister fluid of healthy donors. BP230 and Dsg1 were not detectable in EVs of any of the samples. No specific clinical characteristics seemed to correlate to the presence of BP180 in EVs. The discovery of BP180 in EVs derived from blister fluid might help understanding BP pathogenesis.

Spheroid size influences cellular senescence and angiogenic potential of mesenchymal stromal cell-derived soluble factors and extracellular vesicles.

Introduction: The secretome of mesenchymal stromal cells (MSCs) serves as an innovative tool employed in the regenerative medicine approach. In this particular context, three-dimensional (3D) culture systems are widely utilized to better replicate in vivo conditions and facilitate prolonged cell maintenance during culture. The use of spheroids enables the preservation of the classical phenotypical characteristics of MSCs. However, the distinct microenvironment within the spheroid may impact the secretome, thereby enhancing the angiogenic properties of adult MSCs that typically possess a reduced angiogenic potential compared to MSCs derived from perinatal tissues due to the hypoxia created in the internal region of the spheroid. Methods: In this study, large spheroids (2,600 cells, ∼300 µm diameter) and small spheroids (1,000 cells, ∼200 µm diameter) were used to examine the role of spheroid diameter in the generation of nutrients and oxygen gradients, cellular senescence, and the angiogenic potential of secreted factors and extracellular vesicles (EVs). Results: In this study, we demonstrate that large spheroids showed increased senescence and a secretome enriched in pro-angiogenic factors, as well as pro-inflammatory and anti-angiogenic cytokines, while small spheroids exhibited decreased senescence and a secretome enriched in pro-angiogenic molecules. We also demonstrated that 3D culture led to a higher secretion of EVs with classical phenotypic characteristics. Soluble factors and EVs from small spheroids exhibited higher angiogenic potential in a human umbilical vein endothelial cell (HUVEC) angiogenic assay. Discussion: These findings highlighted the necessity of choosing the appropriate culture system for obtaining soluble factors and EVs for specific therapeutic applications.

Regenerative and Anti-Inflammatory Potential of Regularly Fed, Starved Cells and Extracellular Vesicles In Vivo.

BACKGROUND: Mesenchymal stem/stromal cells (MSC) have been employed successfully in immunotherapy and regenerative medicine, but their therapeutic potential is reduced considerably by the ischemic environment that exists after transplantation. The assumption that preconditioning MSC to promote quiescence may result in increased survival and regenerative potential upon transplantation is gaining popularity. METHODS: The purpose of this work was to evaluate the anti-inflammatory and regenerative effects of human bone marrow MSC (hBM-MSC) and their extracellular vesicles (EVs) grown and isolated in a serum-free medium, as compared to starved hBM-MSC (preconditioned) in streptozotocin-induced diabetic fractured male C57BL/6J mice. RESULTS: Blood samples taken four hours and five days after injection revealed that cells, whether starved or not, generated similar plasma levels of inflammatory-related cytokines but lower levels than animals treated with EVs. Nonetheless, starved cells prompted the highest production of IL-17, IL-6, IL-13, eotaxin and keratinocyte-derived chemokines and induced an earlier soft callus formation and mineralization of the fracture site compared to EVs and regularly fed cells five days after administration. CONCLUSIONS: Preconditioning may be crucial for refining and defining new criteria for future MSC therapies. Additionally, the elucidation of mechanisms underpinning an MSC's survival/adaptive processes may result in increased cell survival and enhanced therapeutic efficacy following transplantation.

Investigating the Paracrine Role of Perinatal Derivatives: Human Amniotic Fluid Stem Cell-Extracellular Vesicles Show Promising Transient Potential for Cardiomyocyte Renewal.

Cardiomyocyte renewal represents an unmet clinical need for cardiac regeneration. Stem cell paracrine therapy has attracted increasing attention to resurge rescue mechanisms within the heart. We previously characterized the paracrine effects that human amniotic fluid-derived stem cells (hAFSC) can exert to provide cardioprotection and enhance cardiac repair in preclinical models of myocardial ischemia and cardiotoxicity. Here, we analyze whether hAFSC secretome formulations, namely, hAFSC conditioned medium (hAFSC-CM) over extracellular vesicles (hAFSC-EVs) separated from it, can induce cardiomyocyte renewal. c-KIT+ hAFSC were obtained by leftover samples of II trimester prenatal amniocentesis (fetal hAFSC) and from clinical waste III trimester amniotic fluid during scheduled C-section procedures (perinatal hAFSC). hAFSC were primed under 1% O2 to enrich hAFSC-CM and EVs with cardioactive factors. Neonatal mouse ventricular cardiomyocytes (mNVCM) were isolated from cardiac tissue of R26pFUCCI2 mice with cell cycle fluorescent tagging by mutually exclusive nuclear signal. mNVCM were stimulated by fetal versus perinatal hAFSC-CM and hAFSC-EVs to identify the most promising formulation for in vivo assessment in a R26pFUCCI2 neonatal mouse model of myocardial infarction (MI) via intraperitoneal delivery. While the perinatal hAFSC secretome did not provide any significant cardiogenic effect, fetal hAFSC-EVs significantly sustained mNVCM transition from S to M phase by 2-fold, while triggering cytokinesis by 4.5-fold over vehicle-treated cells. Treated mNVCM showed disorganized expression of cardiac alpha-actinin, suggesting cytoskeletal re-arrangements prior to cell renewal, with a 40% significant downregulation of Cofilin-2 and a positive trend of polymerized F-Actin. Fetal hAFSC-EVs increased cardiomyocyte cell cycle progression by 1.8-fold in the 4-day-old neonatal left ventricle myocardium short term after MI; however, such effect was lost at the later stage. Fetal hAFSC-EVs were enriched with a short isoform of Agrin, a mediator of neonatal heart regeneration acting by YAP-related signaling; yet in vitro application of YAP inhibitor verteporfin partially affected EV paracrine stimulation on mNVCM. EVs secreted by developmentally juvenile fetal hAFSC can support cardiomyocyte renewal to some extension, via intercellular conveyance of candidates possibly involving Agrin in combination with other factors. These perinatal derivative promising cardiogenic effects need further investigation to define their specific mechanism of action and enhance their potential translation into therapeutic opportunity.

Role of extracellular vesicles from adipose tissue- and bone marrow-mesenchymal stromal cells in endothelial proliferation and chondrogenesis.

The secretome of mesenchymal stromal cells (MSCs) derived from different tissue sources is considered an innovative therapeutic tool for regenerative medicine. Although adipose tissue-and bone marrow-derived MSCs (ADSCs and BMSCs, respectively) share many biological features, the different tissue origins can be mirrored by variations in their secretory profile, and in particular in the secreted extracellular vesicles (EVs). In this study, we carried out a detailed and comparative characterization of middle- and small-sized EVs (mEVs and sEVs, respectively) released by either ADSCs or BMSCs. Their involvement in an endochondral ossification setting was investigated using ex vivo metatarsal culture models that allowed to explore both blood vessel sprouting and bone growth plate dynamics. Although EVs separated from both cell sources presented similar characteristics in terms of size, concentration, and marker expression, they exhibited different characteristics in terms of protein content and functional effects. ADSC-EVs overexpressed pro-angiogenic factors in comparison to the BMSC-counterpart, and, consequently, they were able to induce a significant increase in endothelial cord outgrowth. On the other hand, BMSC-EVs contained a higher amount of pro-differentiation and chemotactic proteins, and they were able to prompt growth plate organization. The present study highlights the importance of selecting the appropriate cell source of EVs for targeted therapeutic applications.

Progenitor Cells Activated by Platelet Lysate in Human Articular Cartilage as a Tool for Future Cartilage Engineering and Reparative Strategies.

Regenerative strategies for human articular cartilage are still challenging despite the presence of resident progenitor cell population. Today, many efforts in the field of regenerative medicine focus on the use of platelet derivatives due to their ability to reactivate endogenous mechanisms supporting tissue repair. While their use in orthopedics continues, mechanisms of action and efficacy need further characterization. We describe that the platelet lysate (PL) is able to activate chondro-progenitor cells in a terminally differentiated cartilage tissue. Primary cultures of human articular chondrocytes (ACs) and cartilage explants were set up from donor hip joint biopsies and were treated in vitro with PL. PL recruited a chondro-progenitors (CPCs)-enriched population from ex vivo cartilage culture, that showed high proliferation rate, clonogenicity and nestin expression. CPCs were positive for in vitro tri-lineage differentiation and formed hyaline cartilage-like tissue in vivo without hypertrophic fate. Moreover, the secretory profile of CPCs was analyzed, together with their migratory capabilities. Some CPC-features were also induced in PL-treated ACs compared to fetal bovine serum (FBS)-control ACs. PL treatment of human articular cartilage activates a stem cell niche responsive to injury. These facts can improve the PL therapeutic efficacy in cartilage applications.

The Secretome Derived From Mesenchymal Stromal Cells Cultured in a Xeno-Free Medium Promotes Human Cartilage Recovery in vitro.

Osteoarthritis (OA) is a disabling joint disorder causing articular cartilage degeneration. Currently, the treatments are mainly aimed to pain and symptoms relief, rather than disease amelioration. Human bone marrow stromal cells (hBMSCs) have emerged as a promising paracrine mechanism-based tool for OA treatment. Here, we investigate the therapeutic potential of conditioned media (CM) and extracellular vesicles (EVs) isolated from hBMSC and grown in a xeno-free culture system (XFS) compared to the conventional fetal bovine serum-culture system (FBS) in an in vitro model of OA. First, we observed that XFS promoted growth and viability of hBMSCs compared to FBS-containing medium while preserving their typical phenotype. The biological effects of the CM derived from hBMSC cultivated in XFS- and FBS-based medium were tested on IL-1α treated human chondrocytes, to mimic the OA enviroment. Treatment with CM derived from XFS-cultured hBMSC inhibited IL-1α-induced expression of IL-6, IL-8, and COX-2 by hACs compared to FBS-based condition. Furthermore, we observed that hBMSCs grown in XFS produced a higher amount of EVs compared to FBS-culture. The hBMSC-EVs not only inhibit the adverse effects of IL-1α-induced inflammation, but play a significant in vitro chondroprotective effect. In conclusion, the XFS medium was found to be suitable for isolation and expansion of hBMSCs with increased safety profile and intended for ready-to-use clinical therapies.

Growth Factors Delivery System for Skin Regeneration: An Advanced Wound Dressing.

Standard treatments of chronic skin ulcers based on the direct application of dressings still present several limits with regard to a complete tissue regeneration. Innovative strategies in tissue engineering offer materials that can tune cell behavior and promote growth tissue favoring cell recruitment in the early stages of wound healing. A combination of Alginate (Alg), Sericin (SS) with Platelet Lysate (PL), as a freeze-dried sponge, is proposed to generate a bioactive wound dressing to care skin lesions. Biomembranes at different composition were tested for the release of platelet growth factors, cytotoxicity, protective effects against oxidative stress and cell proliferation induction. The highest level of the growth factors release occurred within 48 h, an optimized time to burst a healing process in vivo; the presence of SS differently modulated the release of the factors by interaction with the proteins composing the biomembranes. Any cytotoxicity was registered, whereas a capability to protect cells against oxidative stress and induce proliferation was observed when PL was included in the biomembrane. In a mouse skin lesion model, the biomembranes with PL promoted the healing process, inducing an accelerated and more pronounced burst of inflammation, formation of granulation tissue and new collagen deposition, leading to a more rapid skin regeneration.

Beta-tricalcium phosphate ceramic triggers fast and robust bone formation by human mesenchymal stem cells.

Due to their osteoconductive and inductive properties, a variety of calcium phosphate (CaP) scaffolds are commonly used in orthopaedics as graft material to heal bone defects. In this study, we have used two CaP scaffolds with different hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP) ratios (MBCP®; 60/40 and MBCP+ ®; 20/80) to investigate their intrinsic capacity to favour human bone marrow stem cells (hBMSCs) osteogenic differentiation capacity. We report that MBCP+ ® showed in in vitro culture model a higher rate of calcium ion release in comparison with MBCP®. In two defined coculture systems, the hBMSC seeded onto MBCP+ ® presented an increased amount of VEGF secretion, resulting in an enhanced endothelial cell proliferation and capillary formation compared with hBMSC seeded onto MBCP®. When both ceramics combined with hBMSC were implanted in a nude mouse model, we observed a faster osteogenic differentiation and enhancement mature bone deposition sustained by the presence of a vast host vasculature within the MBCP+ ® ceramics. Bone formation was observed in samples highly positive to the activation of calcium sensing receptor protein (CaSr) on the surface of seeded hBMSC that also shown higher BMP-2 protein expression. With these data we provide valuable insights in the possible mechanisms of ossification and angiogenesis by hBMSC that we believe to be primed by calcium ions released from CaP scaffolds. Evidences could lead to an optimization of ceramic scaffolds to prime bone repair.

Phenotypic characterization of Grm1crv4 mice reveals a functional role for the type 1 metabotropic glutamate receptor in bone mineralization.

Recent increasing evidence supports a role for neuronal type signaling in bone. Specifically glutamate receptors have been found in cells responsible for bone remodeling, namely the osteoblasts and the osteoclasts. While most studies have focused on ionotropic glutamate receptors, the relevance of the metabotropic glutamate signaling in bone is poorly understood. Specifically type 1 metabotropic glutamate (mGlu1) receptors are expressed in bone, but the effect of its ablation on skeletal development has never been investigated. Here we report that Grm1crv4/crv4 mice, homozygous for an inactivating mutation of the mGlu1 receptor, and mainly characterized by ataxia and renal dysfunction, exhibit decreased body weight, bone length and bone mineral density compared to wild type (WT) animals. Blood analyses of the affected mice demonstrate the absence of changes in circulating factors, such as vitamin D and PTH, suggesting renal damage is not the main culprit of the skeletal phenotype. Cultures of osteoblasts lacking functional mGlu1 receptors exhibit less homogeneous collagen deposition than WT cells, and present increased expression of osteocalcin, a marker of osteoblast maturation. These data suggest that the skeletal damage is directly linked to the absence of the receptor, which in turn leads to osteoblasts dysfunction and earlier maturation. Accordingly, skeletal histomorphology suggests that Grm1crv4/crv4 mice exhibit enhanced bone maturation, resulting in premature fusion of the growth plate and shortened long bones, and further slowdown of bone apposition rate compared to the WT animals. In summary, this work reveals novel functions of mGlu1 receptors in the bone and indicates that in osteoblasts mGlu1 receptors are necessary for production of normal bone matrix, longitudinal bone growth, and normal skeletal development.

Human Articular Chondrocytes Regulate Immune Response by Affecting Directly T Cell Proliferation and Indirectly Inhibiting Monocyte Differentiation to Professional Antigen-Presenting Cells.

Autologous chondrocyte implantation is the current gold standard cell therapy for cartilage lesions. However, in some instances, the heavily compromised health of the patient can either impair or limit the recovery of the autologous chondrocytes and a satisfactory outcome of the implant. Allogeneic human articular chondrocytes (hAC) could be a good alternative, but the possible immunological incompatibility between recipient and hAC donor should be considered. Herein, we report that allogeneic hAC inhibited T lymphocyte response to antigen-dependent and -independent proliferative stimuli. This effect was maximal when T cells and hAC were in contact and it was not relieved by the addition of exogenous lymphocyte growth factor interleukin (IL)-2. More important, hAC impaired the differentiation of peripheral blood monocytes induced with granulocyte monocyte colony-stimulating factor and IL-4 (Mo) to professional antigen-presenting cells, such as dendritic cells (DC). Indeed, a marked inhibition of the onset of the CD1a expression and an ineffective downregulation of CD14 antigens was observed in Mo-hAC co-cultures. Furthermore, compared to immature or mature DC, Mo from Mo-hAC co-cultures did not trigger an efficacious allo-response. The prostaglandin (PG) E2 present in the Mo-hAC co-culture conditioned media is a putative candidate of the hAC-mediated inhibition of Mo maturation. Altogether, these findings indicate that allogeneic hAC inhibit, rather than trigger, immune response and strongly suggest that an efficient chondrocyte implantation could be possible also in an allogeneic setting.

A humanized system to expand in vitro amniotic fluid-derived stem cells intended for clinical application.

BACKGROUND AIMS: The amniotic fluid is a new source of multipotent stem cells with therapeutic potential for human diseases. In agreement with the regulatory requirement to reduce and possibly to avoid animal-derived reagents in the culture of cells intended for cell therapy, bovine serum, the most common supplement in the culture medium, was replaced by human platelet-derived growth factors. METHODS: We tested a new culture medium to expand monolayers of human amniotic fluid stem cells (hAFSC) for clinical use. The AFSC were isolated by c-Kit selection and expanded in media supplemented with either bovine serum or a human platelet lysate (Lyset). RESULTS: We compared proliferation kinetics, colony-forming unit percentage, multilineage differentiation, immunophenotypic characterization and inhibition of peripheral blood mononuclear cell proliferation of the two AFSC cell cultures and we found no significant differences. Moreover, the karyotype analysis of the cells expanded in the presence of the platelet lysate did not present cytogenetic abnormalities and in vitro and in vivo studies revealed no cell tumorigenicity. CONCLUSIONS: Platelet derivatives represent a rich source of growth factors that can play a safety role in the homeostasis, proliferation and remodeling of tissue healing. We propose human platelet extracts as a preferential alternative to animal serum for the expansion of stem cells for clinical applications.

Growth trend of small uterine fibroids and human chorionic gonadotropin serum levels in early pregnancy: an observational study.

OBJECTIVE: To analyze the growth trend of small uterine fibroids during early pregnancy, evaluating the potential factors involved, with particular interest in hCG levels. DESIGN: Observational study. SETTING: Tertiary care university hospital. PATIENT(S): Women who had an ultrasound diagnosis of small myomas (diameter, ≥10 mm and ≤50 mm) from January 2007 to December 2013, and who subsequently became pregnant within 1 year. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Three additional ultrasound examinations were performed during early pregnancy (7-8, 10-13, and 20-22 complete gestational weeks, respectively) and the modifications in diameter and volume of each uterine fibroid were recorded. A serial evaluation of hCG serum levels from 5-12 weeks was performed. RESULT(S): From the 109 women who fulfilled the study inclusion/exclusion criteria, a significant increase emerged, both for volume and diameter of the detected fibroids. Specifically, a median growth rate (GR) of 122% was observed during the interval of the first to the second ultrasound, whereas a median GR of 108% was detected during the interval between the second and the third ultrasound, and a median GR of 25% between the third and the fourth ultrasound. A significant positive correlation between hCG levels and diameter (R = 0.69) of myomas between 5 and 12 weeks emerged. CONCLUSION(S): A remarkable nonlinear growth of small fibroids during initial pregnancy was observed, with a faster rate in the first trimester and a slowdown by midpregnancy. Those changes seem to be related to the similar increase of hCG levels until 12 weeks.

Loop electrosurgical excision procedure and risk of miscarriage.

OBJECTIVE: To evaluate the risk of miscarriage in the subsequent pregnancy after a loop electrosurgical excision procedure (LEEP), also considering time elapsed from LEEP to pregnancy. DESIGN: Multicenter, retrospective cohort study. SETTING: Tertiary care university hospitals. PATIENT(S): Women who had undergone LEEP from January 2000 to December 2011. Women with histologic assessment of low-grade cervical dysplasia, not requiring subsequent surgical treatment, constituted the control group. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The first pregnancy after the procedure was evaluated, and only women with singleton spontaneous pregnancies were considered. Women with time intervals of <12 months and women with intervals of ≥12 months or more from LEEP to pregnancy were then compared, to identify adjusted odds ratios for miscarriage. RESULT(S): In women previously treated with LEEP, a total of 116 cases of miscarriage (18.1%) was reported. The mean time interval from LEEP to pregnancy for women with miscarriage compared with women without miscarriage was significantly shorter (25.1 ± 11.7 months vs. 30.1 ± 13.3 months). A higher rate of miscarriage in women with a LEEP-to-pregnancy interval of <12 months compared with controls emerged (28.2% vs. 13.4%; adjusted odds ratio 2.60, 95% confidence interval 1.57-4.3). No significant difference in the rate of miscarriage in women with a LEEP-to-pregnancy interval of ≥12 months compared with controls emerged. CONCLUSION(S): Women with a time interval from LEEP to pregnancy of <12 months are at increased risk for miscarriage.

Tissue engineering approaches in skeletal pediatric disorders.

The therapeutic use of stem cells is a very promising strategy in the area of regenerative medicine. The stem cell regenerative paradigm has been mostly based on the assumption that progenitor cells play a critical role in tissue repair by their plasticity and differentiation potential. However, recent works suggest that the mechanism underlying the benefits of stem cell transplantation might relate to a paracrine modulatory effect rather than the replacement of affected cells at the site of injury. Preclinical and clinical skeletal studies, conducted in animal and adult series, support the use of mesenchymal stem cells (MSCs) for bone healing in critical clinical situations. These results have led to an increasing number of papers reporting the use of MSCs in adult clinical trials, whereas only few papers reported the use of these cells in pediatric skeletal disorders, probably because of unknown long-term results and long-life consequences of cellular therapy. The exponential growth of knowledge in adult MSCs could be translated and applied to pediatric disorders. Pediatric osteoarticular diseases have an enormous potential to be treated by MSCs, as severe congenital bone or local cartilage defects, not responding to conventional surgery treatment, might be successfully treated by cellular therapy. Translating basic stem cell research into routine therapies is a complex multistep process which entails the managing of the expected therapeutic benefits with the potential risks in correlation within the existing regulations. Here, we reported the state of art on the use of MSC in skeletal pediatric disorders.

Cartilage repair in the knee with subchondral drilling augmented with a platelet-rich plasma-immersed polymer-based implant.

PURPOSE: The aim of our study was to analyse the clinical and histological outcome after the treatment of focal cartilage defects in non-degenerative and degenerative knees with bone marrow stimulation and subsequent covering with a cell-free resorbable polyglycolic acid-hyaluronan (PGA-HA) implant immersed with autologous platelet-rich plasma (PRP). METHODS: Fifty-two patients (mean age 44 years) with focal chondral defects in radiologically confirmed non-degenerative or degenerative knees were subjected to subchondral drilling arthroscopically. Subsequently, defects were covered with the PGA-HA implant immersed with autologous PRP. At 2-year follow-up, the patients' situation was assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and compared to the pre-operative situation and 3-12-month follow-up. Biopsies (n = 4) were harvested at 18-24 months after implantation and were analysed by histology and collagen type II immune staining. RESULTS: At 1- and 2-year follow-up, the KOOS showed clinically meaningful and significant (p < 0.05) improvement in all subcategories compared to baseline and to 3-month follow-up. There were no differences in KOOS data obtained after 2 years compared to 1 year after the treatment. Histological analysis of the biopsy tissue showed hyaline-like to hyaline cartilage repair tissue that was rich in cells with a chondrocyte morphology, proteoglycans and type II collagen. CONCLUSIONS: Covering of focal cartilage defects with the PGA-HA implant and PRP after bone marrow stimulation improves the patients' situation and has the potential to regenerate hyaline-like cartilage. LEVEL OF EVIDENCE: Case series, Level IV.

Amniotic fluid stem cells in a bone microenvironment: driving host angiogenic response.

The repair of skeletal defects remains a substantial economic and biomedical burden. The extra-embryonic fetal stem cells derived from amniotic fluid (AFSCs) have been used for the treatment of large bone defects, but mechanisms of repair are not clear. Here we studied the potential contribution of human AFSCs to the modeling of an ectopic bone. We found that AFSCs are not osteogenic in vivo, and, compared to bone marrow-derived stromal cells, recruit more host CD31 and VEGF-R2 positive cells. Finally, when AFSCs were co-implanted with human-bone forming cells, a normo-osteosynthesis occurred, the engineered ossicle was hyper-vascularized, but AFSCs were not retrieved in the implant within 2weeks. We concluded that AFSCs do not contribute to the deposition of new bone, but act as a powerful proinflammatory/proangiogenic boost, driving a host response, ending in AFSC clearance and vascularization of the bone environment. In our model, a source of osteocommitted cells, capable to engraft and proliferate in vivo, is needed in order to engineer bone. The angio-attractant properties of AFSCs could be exploited in strategies of endogenous cell homing to actively recruit host progenitors into a predefined anatomic location for in situ bone tissue regeneration.