Ionized jet deposition of silver nanostructured coatings: Assessment of chemico-physical and biological behavior for application in orthopedics

Infection is one of the main issues connected to implantation of biomedical devices and represents a very difficult issue to tackle, for clinicians and for patients. This study aimed at tackling infection through antibacterial nanostructured silver coatings manufactured by Ionized Jet Deposition (IJD) for application as new and advanced coating systems for medical devices. Films composition and morphology depending on deposition parameters were investigated and their performances evaluated by correlating these properties with the antibacterial and antibiofilm efficacy of the coatings, against Escherichia coli and Staphylococcus aureus strains and with their cytotoxicity towards human cell line fibroblasts. The biocompatibility of the coatings, the nanotoxicity, and the safety of the proposed approach were evaluated, for the first time, in vitro and in vivo by rat subcutaneous implant models. Different deposition times, corresponding to different thicknesses, were selected and compared. All silver coatings exhibited a highly homogeneous surface composed of nanosized spherical aggregates. All coatings having a thickness of 50 nm and above showed high antibacterial efficacy, while none of the tested options caused cytotoxicity when tested in vitro. Indeed, silver films impacted on bacterial strains viability and capability to adhere to the substrate, in a thickness-dependent manner. The nanostructure obtained by IJD permitted to mitigate the toxicity of silver, conferring strong antibacterial and anti-adhesive features, without affecting the coatings biocompatibility. At the explant, the coatings were still present although they showed signs of progressive dissolution, compatible with the release of silver, but no cracking, delamination or in vivo toxicity was observed.

In vivo validation of highly customized cranial Ti-6AL-4V ELI prostheses fabricated through incremental forming and superplastic forming: an ovine model study

Cranial reconstructions are essential for restoring both function and aesthetics in patients with craniofacial deformities or traumatic injuries. Titanium prostheses have gained popularity due to their biocompatibility, strength, and corrosion resistance. The use of Superplastic Forming (SPF) and Single Point Incremental Forming (SPIF) techniques to create titanium prostheses, specifically designed for cranial reconstructions was investigated in an ovine model through microtomographic and histomorphometric analyses. The results obtained from the explanted specimens revealed significant variations in bone volume, trabecular thickness, spacing, and number across different regions of interest (VOIs or ROIs). Those regions next to the center of the cranial defect exhibited the most immature bone, characterized by higher porosity, decreased trabecular thickness, and wider trabecular spacing. Dynamic histomorphometry demonstrated differences in the mineralizing surface to bone surface ratio (MS/BS) and mineral apposition rate (MAR) depending on the timing of fluorochrome administration. A layer of connective tissue separated the prosthesis and the bone tissue. Overall, the study provided validation for the use of cranial prostheses made using SPF and SPIF techniques, offering insights into the processes of bone formation and remodeling in the implanted ovine model.

Histological and histomorphometric analysis of bone tissue using customized titanium meshes with or without resorbable membranes: A randomized clinical trial

OBJECTIVES

To date, no clinical studies have investigated the effect of using resorbable collagen membrane in conjunction with customized titanium mesh to promote bone formation in guided bone regeneration. Therefore, a non-inferiority analysis (one-sided 95% CI approach) was designed to compare the augmented bone gained using meshes with and without collagen membranes, through histological and histomorphometric investigations.

MATERIALS AND METHODS

Thirty patients undergoing bone augmentation procedures at both maxillary and mandible sites were randomly treated with customized titanium meshes alone (M-, n = 15) or covered with resorbable membrane (M+, n = 15), in both cases filled with autogenous bone and xenograft. After 6 months of healing, bone tissue biopsies were taken from the augmented region. The bone tissue (B.Ar), grafting material (G.Ar), and non-mineralized tissue (NMT.Ar) areas were quantified through histomorphometric analysis, as were the osteoid area (O.Ar) and its width.

RESULTS

Collagen membrane did not appear to significantly influence the investigated parameters: B.Ar, G.Ar, NMT.Ar, and O.Ar were similar between Group M- (34.3%, 11.5%, 54.1%, 1.95 μm2 , respectively) and Group M+ (35.3%, 14.6%, 50.2%, and 1.75 μm2 , respectively). Considering the overall population, significantly higher rates of newly formed bone were obtained in mandibular sites, while non-mineralized and dense connective tissue rates were higher in the maxilla (p < .05).

CONCLUSIONS

The application of collagen membrane over titanium mesh did not lead to significant results. Bone formation appeared significantly different in the maxilla compared with the mandible. Additional studies are required to further investigate the issues observed.

A Systematic Review of the Retrograde Drilling Approach for Osteochondral Lesion of the Talus: Questioning Surgical Approaches, Outcome Evaluation and Gender-Related Differences

BACKGROUND

Retrograde drilling (RD) is a minimally invasive surgical procedure mainly used for non-displaced osteochondral lesions (OCL) of the talus, dealing with subchondral necrotic sclerotic lesions or subchondral cysts without inducing iatrogenic articular cartilage injury, allowing the revascularization of the subchondral bone and new bone formation.

METHODS

This systematic review collected and analyzed the clinical studies of the last 10 years of literature, focusing not only on the clinical results but also on patients' related factors (gender, BMI, age and complications).

RESULTS

Sixteen clinical studies were retrieved, and differences in the type of study, follow-up, number and age of patients, lesion type, dimensions, grades and comparison groups were observed, making it difficult to draw conclusions. Nevertheless, lesions on which RD showed the best results were those of I-III grades and not exceeding 150 mm² in size, showing overall positive results, a good rate of patient satisfaction, improvements in clinical scores, pain reduction and return to daily activities and sports.

CONCLUSIONS

There are still few studies dealing with the issue of post-surgical complications and gender-related responses. Further clinical or preclinical studies are thus mandatory to underline the success of this technique, also in light of gender differences.

Bone Regeneration Guided by a Magnetized Scaffold in an Ovine Defect Model

The reconstruction of large segmental defects still represents a critical issue in the orthopedic field. The use of functionalized scaffolds able to create a magnetic environment is a fascinating option to guide the onset of regenerative processes. In the present study, a porous hydroxyapatite scaffold, incorporating superparamagnetic Fe₃O₄ nanoparticles (MNPs), was implanted in a critical bone defect realized in sheep metatarsus. Superparamagnetic nanoparticles functionalized with hyperbranched poly(epsilon-Lysine) peptides and physically complexed with vascular endothelial growth factor (VEGF) where injected in situ to penetrate the magnetic scaffold. The scaffold was fixed with cylindrical permanent NdFeB magnets implanted proximally, and the magnetic forces generated by the magnets enabled the capture of the injected nanoparticles forming a VEGF gradient in its porosity. After 16 weeks, histomorphometric measurements were performed to quantify bone growth and bone-to-implant contact, while the mechanical properties of regenerated bone via an atomic force microscopy (AFM) analysis were investigated. The results showed increased bone regeneration at the magnetized interface; this regeneration was higher in the VEGF-MNP-treated group, while the nanomechanical behavior of the tissue was similar to the pattern of the magnetic field distribution. This new approach provides insights into the ability of magnetic technologies to stimulate bone formation, improving bone/scaffold interaction.

Anisotropy and inhomogeneity of permeability and fibrous network response in the pars intermedia of the human lateral meniscus

Within the human tibiofemoral joint, meniscus plays a key role due to its peculiar time-dependent mechanical characteristics, inhomogeneous structure and compositional features. To better understand the pathophysiological mechanisms underlying this essential component, it is mandatory to analyze in depth the relationship between its structure and the function it performs in the joint. Accordingly, the aim of this study was to evaluate the behavior of both solid and fluid phases of human meniscus in response to compressive loads, by integrating mechanical assessment and histological analysis. Cubic specimens were harvested from seven knee lateral menisci, specifically from anterior horn, pars intermedia and posterior horn; unconfined compressive tests were then performed according to three main loading directions (i.e., radial, circumferential and vertical). Fibril modulus, matrix modulus and hydraulic permeability of the tissue were thence estimated through a fibril-network-reinforced biphasic model. Tissue porosity and collagen fibers arrangement were assessed through histology for each region and related to the loading directions adopted during mechanical tests. Regional and strain-dependent constitutive parameters were finally proposed for the human lateral meniscus, suggesting an isotropic behavior of both the horns, and a transversely isotropic response of the pars intermedia. Furthermore, the histological findings supported the evidences highlighted by the compressive tests. Indeed, this study provided novel insights concerning the functional behavior of human menisci by integrating mechanical and histological characterizations and thus highlighting the key role of this component in knee contact mechanics and presenting fundamental information that can be used in the development of tissue-engineered substitutes. STATEMENT OF SIGNIFICANCE: This work presents an integration to the approaches currently used to model the mechanical behavior of the meniscal tissue. This study assessed in detail the regional and directional contributions of both the meniscal solid and fluid phases during compressive response, providing also complementary histological evidence. Within this updated perspective, both knee computational modeling and meniscal tissue engineering can be improved to have an effective impact on the clinical practice.

Skin adhesion to the percutaneous component of direct bone anchored systems: systematic review on preclinical approaches and biomaterials

Nowadays, direct bone anchored systems are an increasingly adopted approach in the therapeutic landscape for amputee patients. However, the percutaneous nature of these devices poses a major challenge to obtain a stable and lasting proper adhesion between the implant surface and the skin. A systematic review was carried out in three databases (PubMed, Scopus, Web of Science) to provide an overview of the innovative strategies tested with preclinical models (in vitro and in vivo) in the last ten years to improve the skin adhesion of direct bone anchored systems. Fifty five articles were selected after screening, also employing PECO question and inclusion criteria. A modified Cochrane RoB 2.0 tool for the in vitro studies and the SYRCLE tool for in in vivo studies were used to assess the risk of bias. The evidence collected suggests that the implementation of porous percutaneous structures could be one of the most favorable approach to improve proper skin adhesion, especially in association with bioactive coatings, as hydroxyapatite, and exploiting the field of nanostructure. Some issues still remain open as (a) the identification and characterization of the best material/coating association able to limit the shear stresses at the interface and (b) the role of keratinocyte turnover on the skin/biomaterial adhesion and integration processes.

Vitamin D and Platelets: A Menacing Duo in COVID-19 and Potential Relation to Bone Remodeling

Global data correlate severe vitamin D deficiency with COVID-19-associated coagulopathy, further suggesting the presence of a hypercoagulable state in severe COVID-19 patients, which could promote thrombosis in the lungs and in other organs. The feedback loop between COVID-19-associated coagulopathy and vitamin D also involves platelets (PLTs), since vitamin D deficiency stimulates PLT activation and aggregation and increases fibrinolysis and thrombosis. Vitamin D and PLTs share and play specific roles not only in coagulation and thrombosis but also during inflammation, endothelial dysfunction, and immune response. Additionally, another ‘fil rouge’ between vitamin D and PLTs is represented by their role in mineral metabolism and bone health, since vitamin D deficiency, low PLT count, and altered PLT-related parameters are linked to abnormal bone remodeling in certain pathological conditions, such as osteoporosis (OP). Hence, it is possible to speculate that severe COVID-19 patients are characterized by the presence of several predisposing factors to bone fragility and OP that may be monitored to avoid potential complications. Here, we hypothesize different pervasive actions of vitamin D and PLT association in COVID-19, also allowing for potential preliminary information on bone health status during COVID-19 infection.

Blood factors as biomarkers in osteoporosis: points from the COVID-19 era

The restrictions adopted during the coronavirus disease 2019 (COVID-19) pandemic limiting direct medical consultations and access to healthcare centers reduced the participation of patients with chronic diseases, such as osteoporosis (OP), in screening and monitoring programs. This highlighted the need for new screening diagnostic tools that are clinically effective, but require minimal technical and time commitments, to stratify populations and identify who is more at risk for OP and related complications. This paper provides an overview of the potential use of blood-related factors, such as platelet (PLT)- and monocyte-related factors, as biomarkers able to quickly screen, detect, and monitor OP in both sexes. Such biomarkers might be of key importance not only during the COVID-19 pandemic but also, even more importantly, during periods of better global health stability.

Osseointegration of additive manufacturing Ti-6Al-4V and Co-Cr-Mo alloys, with and without surface functionalization with hydroxyapatite and type I collagen

The introduction of additive manufacturing (AM) technologies has profoundly revolutionized the implant manufacturing industry, with a particularly significant impact on the field of orthopedics. Electron Beam Melting (EBM) and Direct Metal Laser Sintering (DMLS) represents AM fabrication techniques with a pivotal role in the realization of complex and innovative structure starting from virtual 3D model data. In this study, Ti-6Al-4V and Co-Cr-Mo materials, developed by EBM (Ti-POR) and DMLS (Co-POR) techniques, respectively, with hydroxyapatite (Ti-POR + HA; Co-POR + HA) and type I collagen (Ti-POR-COLL; Co-POR-COLL) coatings, were implanted into lateral femoral condyles of rabbits. Osseointegration process was investigated by histological, histomorphometrical and microhardness evaluations at 4 and 12 weeks after implantation. Both Ti-6Al-4V and Co-Cr-Mo implants, with or without HA and COLL coatings, demonstrated good biocompatibility. As expected, HA coating hastened bone-to-implant contact (BIC) process, while collagen did not significantly improved the osseointegration process in comparison to controls. Regarding newly trabecular bone formation (B.Ar/T.Ar), Co-POR presented the highest values, significantly different from those of Co-POR-COLL. Over time, an increase of BIC parameter and a decrease of B.Ar/T.Ar were detected. Higher mineral apposition rate was observed for Ti-POR and Co-POR in comparison to Ti-POR-COLL and Co-POR-COLL, respectively, at 12 weeks. The same behavior was found for bone formation rate between Co-POR and Co-POR-COLL at 12 weeks. In conclusion, the AM materials guarantee a good osseointegration and provide a suitable environment for bone regeneration with the peculiarity of allowing personalized and patient-specific needs customization to further improve the long-term clinical outcomes.

Body Localization of ACE-2: On the Trail of the Keyhole of SARS-CoV-2

The explosion of the new coronavirus (SARS-CoV-2) pandemic has brought the role of the angiotensin converting enzyme 2 (ACE2) back into the scientific limelight. Since SARS-CoV-2 must bind the ACE2 for entering the host cells in humans, its expression and body localization are critical to track the potential target organ of this infection and to outline disease progression and clinical outcomes. Here, we mapped the physiological body distribution, expression, and activities of ACE2 and discussed its potential correlations and mutal interactions with the disparate symptoms present in SARS-CoV-2 patients at the level of different organs. We highlighted that despite during SARS-CoV-2 infection ACE2-expressing organs may become direct targets, leading to severe pathological manifestations, and subsequent multiple organ failures, the exact mechanism and the potential interactions through which ACE2 acts in these organs is still heavily debated. Further scientific efforts, also considering a personalized approach aimed to consider specific patient differences in the mutual interactions ACE2-SARS-CoV-2 and the long-term health effects associated with COVID-19 are currently mandatory.

Vascular Supply and Bone Marrow Concentrate for the Improvement of Allograft in Bone Defects: A Comparative In Vivo Study

BACKGROUND

Surgical repair of critical-sized bone defects still remains a big challenge in orthopedic surgery. Biological enhancement, such as growth factors or cells, can stimulate a better outcome in bone regeneration driven by well-established treatments such as allogenic bone graft. However, despite the surgical options available, correct healing can be slowed down or compromised by insufficient vascular supply to the injured site.

MATERIALS AND METHODS

In this pilot study, critical size bone defects in rabbit radius were treated with allograft bone, in combination with vascular bundle and autologous bone marrow concentrate seeded onto a commercial collagen scaffold. Microtomographical, histological and immunohistochemical assessments were performed to evaluate allograft integration and bone regeneration.

RESULTS

Results showed that the surgical deviation of vascular bundle in the bone graft, regardless from the addition of bone marrow concentrate, promote the onset of healing process at short experimental times (8 wk) in comparison with the other groups, enhancing graft integration.

CONCLUSION

The surgical procedure tested stimulates bone healing at early times, preserving native bone architecture, and can be easily combined with biological adjuvant.

Platelet functions and activities as potential hematologic parameters related to Coronavirus Disease 2019 (Covid-19)

Coronavirus disease 2019 (COVID-19) is a new infectious disease that currently lacks standardized and established laboratory markers to evaluate its severity. In COVID-19 patients, the number of platelets (PLTs) and dynamic changes of PLT-related parameters are currently a concern. The present paper discusses the potential link between PLT parameters and COVID-19. Several studies have identified a link between severe COVID-19 patients and specific coagulation index, in particular, high D-dimer level, prolonged prothrombin time, and low PLT count. These alterations reflect the hypercoagulable state present in severe COVID-19 patients, which could promote microthrombosis in the lungs, as well as in other organs. Further information and more advanced hematological parameters related to PLTs are needed to better estimate this link, also considering COVID-19 patients at different disease stages and stratified in different cohorts based on preexisting co-morbidity, age, and gender. Increasing the understanding of PLT functions in COVID-19 will undoubtedly improve our knowledge on disease pathogenesis, clinical management, and therapeutic options, but could also lead to the development of more precise therapeutic strategies for COVID-19 patients.

In vivo studies on osteoinduction: A systematic review on animal models, implant site, and type and postimplantation investigation

Musculoskeletal diseases involving loss of tissue usually require management with bone grafts, among which autografts are still the gold standard. To overcome autograft disadvantages, the development of new scaffolds is constantly increasing, as well as the number of in vivo studies evaluating their osteoinductivity in ectopic sites. The aim of the present systematic review is to evaluate the last 10 years of osteoinduction in vivo studies. The review is focused on: (a) which type of animal model is most suitable for osteoinduction evaluation; (b) what are the most used types of scaffolds; (c) what kind of post-explant evaluation is most used. Through three websites (www.pubmed.com, www.webofknowledge.com and www.embase.com), 77 in vivo studies were included. Fifty-eight studies were conducted in small animal models (rodents) and 19 in animals of medium or large size (rabbits, dogs, goats, sheep, and minipigs). Despite the difficulty in establishing the most suitable animal model for osteoinductivity studies, small animals (in particular mice) are the most utilized. Intramuscular implantation is more frequent than subcutis, especially in large animals, and synthetic scaffolds (especially CaP ceramics) are preferred than natural ones, also in combination with cells and growth factors. Paraffin histology and histomorphometric evaluations are usually employed for postimplantation analyses.

Platelet Features and Derivatives in Osteoporosis: A Rational and Systematic Review on the Best Evidence

Background: With the increase in aging population, the rising prevalence of osteoporosis (OP) has become an important medical issue. Accumulating evidence showed a close relationship between OP and hematopoiesis and emerging proofs revealed that platelets (PLTs), unique blood elements, rich in growth factors (GFs), play a critical role in bone remodeling. The aim of this review was to evaluate how PLT features, size, volume, bioactive GFs released, existing GFs in PLTs and PLT derivatives change and behave during OP. Methods: A systematic search was carried out in PubMed, Scopus, Web of Science Core Collection and Cochrane Central Register of Controlled Trials databases to identify preclinical and clinical studies in the last 10 years on PLT function/features and growth factor in PLTs and on PLT derivatives during OP. The methodological quality of included studies was assessed by QUIPS tool for assessing risk of bias in the clinical studies and by the SYRCLE tool for assessing risk of bias in animal studies. Results: In the initial search, 2761 studies were obtained, only 47 articles were submitted to complete reading, and 23 articles were selected for the analysis, 13 on PLT function/features and growth factor in PLTs and 10 on PLT derivatives. Risk of bias of almost all animal studies was high, while the in the clinical studies risk of bias was prevalently moderate/low for the most of the studies. The majority of the evaluated studies highlighted a positive correlation between PLT size/volume and bone mineralization and an improvement in bone regeneration ability by using PLTs bioactive GFs and PLT derivatives. Conclusions: The application of PLT features as OP markers and of PLT-derived compounds as therapeutic approach to promote bone healing during OP need to be further confirmed to provide clear evidence for the real efficacy of these interventions and to contribute to the clinical translation.

Current Trends in the Evaluation of Osteochondral Lesion Treatments: Histology, Histomorphometry, and Biomechanics in Preclinical Models

Osteochondral lesions (OCs) are typically of traumatic origins but are also caused by degenerative conditions, in primis osteoarthritis (OA). On the other side, OC lesions themselves, getting worse over time, can lead to OA, indicating that chondral and OC defects represent a risk factor for the onset of the pathology. Many animal models have been set up for years for the study of OC regeneration, being successfully employed to test different treatment strategies, from biomaterials and cells to physical and biological adjuvant therapies. These studies rely on a plethora of post-explant investigations ranging from histological and histomorphometric analyses to biomechanical ones. The present review aims to analyze the methods employed for the evaluation of OC treatments in each animal model by screening literature data within the last 10 years. According to the selected research criteria performed in two databases, 60 works were included. Data revealed that lapine (50% of studies) and ovine (23% of studies) models are predominant, and knee joints are the most used anatomical locations for creating OC defects. Analyses are mostly conducted on paraffin-embedded samples in order to perform histological/histomorphometric analyses by applying semiquantitative scoring systems and on fresh samples in order to perform biomechanical investigations by indentation tests on articular cartilage. Instead, a great heterogeneity is pointed out in terms of OC defect dimensions and animal's age. The choice of experimental times is generally adequate for the animal models adopted, although few studies adopt very long experimental times. Improvements in data reporting and in standardization of protocols would be desirable for a better comparison of results and for ethical reasons related to appropriate and successful animal experimentation.

Engineered exosomes: A new promise for the management of musculoskeletal diseases

BACKGROUND

Exosomes are nanovesicles actively secreted by potentially all cell types, including tumour cells, with the primary role of extracellular systemic communication mediators, both at autocrine and paracrine levels, at short and long distances. Recently, different studies have used exosomes as a delivery system for a plethora of different molecules, such as drugs, microRNAs and proteins. This has been made possible thanks to the simplicity in exosomes engineering, their great stability and versatility for applications in oncology as well as in regenerative medicine.

SCOPE OF REVIEW

The aim of this review is to provide information on the state-of-the-art and possible applications of engineered exosomes, both for cargo and specific cell-targeting, in different pathologies related to the musculoskeletal system.

MAJOR CONCLUSIONS

The use of exosomes as therapeutic agents is rapidly evolving, different studies explore drug delivery with exosomes using different molecules, showing an enormous potential in various research fields such as oncology and regenerative medicine.

GENERAL SIGNIFICANCE

However, despite the significant progress made by the different studies carried out, currently, the use of exosomes is not a therapeutic reality for the considerable difficulties to overcome.

Intestinal anti-transglutaminase 2 immunoglobulin A deposits in children at risk for coeliac disease (CD): data from the PreventCD study

In coeliac disease (CD), anti-tissue transglutaminase 2 immunoglobulin (Ig)A antibodies (anti-TG2) are produced and deposited in the intestine. PreventCD (www.preventcd.com) is a European multi-centre study, which investigates the influence of infant nutrition and that of genetic, immunological and other environmental factors on the risk of developing CD. The aim of the current study was to evaluate the appearance of intestinal anti-TG2 deposits in very early intestinal biopsies from at-risk infants and their predictive value for villous atrophy. Sixty-five small bowel biopsies, performed in 62 children, were investigated for the presence of intestinal anti-TG2 extracellular IgA deposits by using double immunofluorescence. The biopsies were performed in the presence of elevated serum levels of CD-associated antibodies and/or symptoms suggesting disease. Deposits of anti-TG2 IgA were present in 53 of 53 CD patients and three of three potential CD patients. In potential CD patients, mucosal deposits showed a patchy distribution characterized by some areas completely negative, whereas active CD patients had uniformly present and evident mucosal deposits. Only one of six patients without CD (negative for serum anti-TG2 and with normal mucosa) had intestinal deposits with a patchy distribution and a weak staining. Two of the 53 CD patients received a definitive diagnosis of CD after a second or third biopsy; mucosal deposits of anti-TG2 IgA were evaluated in all samples. Before developing villous atrophy, both patients had anti-TG2 deposits in normal mucosal architecture, antibodies in one patient being absent in serum. We demonstrated that in CD the intestinal deposits of anti-TG2 are a constant presence and appear very early in the natural history of disease.

Vitamin D Level Between Calcium-Phosphorus Homeostasis and Immune System: New Perspective in Osteoporosis

Vitamin D is a key molecule in calcium and phosphate homeostasis; however, increasing evidence has recently shown that it also plays a crucial role in the immune system, both innate and adaptive. A deregulation of vitamin D levels, due also to mutations and polymorphisms in the genes of the vitamin D pathway, determines severe alterations in the homeostasis of the organism, resulting in a higher risk of onset of some diseases, including osteoporosis. This review gives an overview of the influence of vitamin D levels on the pathogenesis of osteoporosis, between bone homeostasis and immune system.

Mesenchymal stem cells for tendon healing: what is on the horizon?

Tendon injuries are a noteworthy morbidity but at present there are few effective scientifically proven treatments. In recent decades, a number of new strategies including tissue engineering with mesenchymal stem cells (MSCs) have been proposed to enhance tendon healing. Although MSCs are an interesting and promising approach, many questions regarding their use in tendon repair remain unanswered. This descriptive overview of the literature of the last decade explores the in vivo studies on tendon healing, in small and large animal models, which used MSCs harvested from different tissues, and the state of the art in clinical applications. It was observed that there are still doubts about the optimum amount of MSCs to use and their source and the type of scaffolds to deliver the cells. Thus, further studies are needed to determine the best protocol for MSC use in tendon healing. Copyright © 2016 John Wiley & Sons, Ltd.

Estrogen-deficient osteoporosis enhances the recruitment and activity of osteoclasts by breast cancer cells

To reduce the burden of bone metastases, the pathophysiology of the metastatic niche should be elucidated and targeted. The aim of the present study was to assess the effect of tumor cells on osteoclast (OC) recruitment and activity in the presence of altered bone remodelling. Peripheral blood mononuclear cells (PBMC) were isolated from healthy and ovariectomized (OVX) rats and co-cultured with MRMT-1 rat breast carcinoma cells or with their conditioned medium for 1 and 2 weeks. Alamar Blue viability test, synthesis of cathepsin K, transforming growth factor-beta 1 (TGF-β1), tumor necrosis factor alpha (TNF-α), vascular endothelial growth factor (VEGF), metalloproteinase (MMP)-7, MMP-9, FITC-conjugate phalloidin staining and tartrate-resistant acid phosphatase (TRAP) staining were evaluated. The results indicate that breast carcinoma cells induced different responses in PBMC derived from rats affected by estrogen deficiency osteoporosis (OP) in comparison with healthy ones, with a significant increase in proliferation rate, OC differentiation, synthesis of TNF-α, MMP-7 and MMP-9. The data support the "proof of concept" that OP due to estrogen deficiency might offer a receptive site for cancer cells to form bone metastases.

In vitro method for the screening and monitoring of estrogen-deficiency osteoporosis by targeting peripheral circulating monocytes

Bone loss occurs insidiously and initially asymptomatically; therefore, osteoporosis is frequently diagnosed only after the first clinical fracture. The aim of this study was to test the hypothesis is that by simply observing the behavior of cultured peripheral monocytes, it might be possible to diagnose altered bone remodeling and, therefore, limit the complications associated with osteoporosis, especially fractures. Monocytes isolated as mononuclear precursors from healthy and ovariectomized rats were cultured both in basal and differentiation medium for up to 3 weeks. Viability and differentiation capability towards the osteoclastic phenotype was checked by light microscopy at early times, whereas differentiation state and synthetic activity (tartrate-resistant acid phosphatase (TRAP) staining; phalloidin, fluorescin isothiocynate (FITC) staining, cathepsin K, metalloproteinase 7 and 9, MMP-7 and MMP-9) were measured at 1, 2, and 3 weeks. Compared to their controls, monocytes isolated from ovariectomized rats proliferate and lean toward the osteoclastic phenotype in the absence of differentiating factors. In both culture conditions, osteoclasts from ovariectomized rats showed significantly higher productions of cathepsin K, MMP-7, and MMP-9 than those of cells isolated from healthy rats, steadily over time. These results obtained in an animal osteoporotic model, if confirmed by clinical studies, open up the possibility to assess the presence of an alteration in bone remodeling with a simple in vitro diagnostic test requiring a small blood sample and less than 48 h. This might allow to early select patients with a spontaneous viability and differentiation of monocytes to osteoclasts for further diagnostic techniques.

Intestinal titres of anti-tissue transglutaminase 2 antibodies correlate positively with mucosal damage degree and inversely with gluten-free diet duration in coeliac disease

It has always been known that anti-tissue transglutaminase 2 (anti-TG2) antibodies are produced in the small intestine. Their serum titres correlate with mucosal damage degree and decrease on a gluten-free diet (GFD). We aimed to correlate intestinal anti-TG2 antibodies levels with degree of mucosal damage and GFD duration. Thirty-four active, 71 potential and 24 CD patients on GFD for at least 2 years were enrolled. Anti-TG2 deposits were detected in intestinal biopsies by double immunofluorescence. Biopsies were cultured for 24 h with medium, and with gliadin peptic tryptic digest (PTG) or A-gliadin peptide 31-43 (P31-43). Anti-TG2 antibodies secreted into supernatants were measured by enzyme-linked immunosorbent assay (ELISA). All active CD patients secreted high titres of anti-TG2 antibodies into culture medium that increased with the worsening of mucosal injury (Spearman's r = 0·71; P < 0·0001). Seventy of 71 potential CD patients and 15 of 24 treated CD patients secreted low titres of anti-TG2 antibodies into supernatants, eight of nine negative treated patients being on GFD for more than 10 years. An inverse correlation between antibody titres and duration of GFD was found, (Spearman's r = -0·52; P < 0·01). All active, 53 of 71 potential and six of 24 treated, CD patients showed anti-TG2 mucosal deposits. Five of six positive treated CD patients had been on GFD for fewer than 6 years and were also positive for secreted anti-TG2. In treated patients, PTG/P31-43 was not able to induce secretion of anti-TG2 antibodies into culture medium. Measurement of anti-TG2 antibodies in biopsy supernatants proved to be more sensitive than detection by immunofluorescence to reveal their intestinal production. Intestinal antiTG2 antibodies titres correlated positively with the degree of mucosal damage and inversely with the duration of GFD.

Adipose-derived mesenchymal stem cells for cartilage tissue engineering: state-of-the-art in in vivo studies

Several therapeutic approaches have been developed to address hyaline cartilage regeneration, but to date, there is no universal procedure to promote the restoration of mechanical and functional properties of native cartilage, which is one of the most important challenges in orthopedic surgery. For cartilage tissue engineering, adult mesenchymal stem cells (MSCs) are considered as an alternative cell source to chondrocytes. Since little is known about adipose-derived mesenchymal stem cell (ADSC) cartilage regeneration potential, the aim of this review was to give an overview of in vivo studies about the chondrogenic potential and regeneration ability of culture-expanded ADSCs when implanted in heterotopic sites or in osteoarthritic and osteochondral defects. The review compares the different studies in terms of number of implanted cells and animals, cell harvesting sites, in vitro expansion and chondrogenic induction conditions, length of experimental time, defect dimensions, used scaffolds and post-explant analyses of the cartilage regeneration. Despite variability of the in vivo protocols, it seems that good cartilage formation and regeneration were obtained with chondrogenically predifferentiated ADSCs (1 × 10(7) cells for heterotopic cartilage formation and 1 × 10(6) cells/scaffold for cartilage defect regeneration) and polymeric scaffolds, even if many other aspects need to be clarified in future studies.

Electrochemotherapy is effective in the treatment of rat bone metastases

Bone metastases impair general health status, quality of life and survival of patients. Electrochemotherapy (ECT), which combines electroporation (EP) and the administration of anticancer drugs, has been recently introduced into clinical practice for the local treatment of solid tumours. In the present study, the ability of EP with bleomycin (Bleo) to induce MRMT-1 rat breast cancer cell death was investigated in vitro. Then, an in vivo model for bone metastases was set up by the inoculation of MRMT-1 cells in rat proximal tibia. 7 days after tumour induction the animals were treated with Bleo, EP, Bleo followed by EP (ECT), or left untreated. ECT eliminated the tumour in 6 out of 8 (75 %) treated metastases. Radiological evaluation showed that the Honore score in ECT-treated animals was significantly lower when compared with the other groups (p < 0.0005) and not significantly different from healthy controls. Bone morphology in ECT-treated animals, evaluated by histological and microtomographical analyses, showed intact cortical and trabecular bone structure with new bone apposition. Histomorphometric evaluation showed that ECT-treated metastases had significantly higher bone volume, trabecular number, trabecular thickness and bone mineral density compared with those of untreated metastases (respectively p < 0.0005 for BV/TV, Tb.N and BMD; p < 0.05 for Tb.Th) or metastases treated with Bleo (p < 0.05 for BV/TV, Tb.N, p < 0.005 for BMD) or EP (p < 0.005 for BV/TV, Tb.N; p < 0.0005 for BMD). These findings suggest that early ECT treatment of bone metastases is minimally invasive, safe and effective, thus providing pre-clinical evidence for its use in the treatment of human bone metastases.

Intestinal anti-tissue transglutaminase antibodies in potential coeliac disease

Anti-tissue transglutaminase 2 (anti-TG2) antibodies are present in the serum of the great majority of untreated coeliac disease (CD) patients. They are produced and deposited in the small intestinal mucosa. Potential CD patients present serum anti-TG2 antibodies higher than cut-off, but a normal duodenal mucosa where mucosal deposits of anti-TG2 are not always detectable. The aim of our work was to investigate the presence of anti-TG2 intestinal antibodies in patients with potential CD, and identify the most sensitive test to detect them. Twelve active CD patients, 28 potential CD patients and 39 non-CD controls were enrolled. Biopsy fragments from all patients were analysed by double immunofluorescence to detect mucosal deposits of anti-TG2 antibodies. Fragments from the same subjects were also cultured for 24 h with medium in the presence or absence of gliadin peptides. Anti-TG2 autoantibodies secreted into supernatants were measured by enzyme-linked immunosorbent assay. All active CD, 68% of potential CD patients and 20% of non-CD controls showed mucosal deposits of immunoglobulin (Ig)A anti-TG2; at the same time 100, 96 and 8% of active CD, potential CD and non-CD control patients secreted these antibodies in culture supernatants, respectively. Our data showed that, to detect intestinal anti-TG2 antibodies, the measurement of antibodies secreted into culture supernatants has higher sensitivity and specificity (97·5 and 92·3%, respectively) than the detection of mucosal deposits (77·5 and 80·0%, respectively). The measurement of intestinal anti-TG2 antibodies may prove useful in clinical practice to predict evolution towards mucosal atrophy in potential coeliac patients and identify patients with gluten sensitivity.

High density of intraepithelial gammadelta lymphocytes and deposits of immunoglobulin (Ig)M anti-tissue transglutaminase antibodies in the jejunum of coeliac patients with IgA deficiency

The diagnosis of coeliac disease (CD) represents a special challenge in selective immunoglobulin (Ig)A deficiency (IgAD). A high density of T cell receptor (TCR)gammadelta(+) intraepithelial lymphocytes (IELs) and intestinal IgA anti-tissue transglutaminase 2 (anti-TG2) antibody deposits are suggestive of CD. We analysed the density of TCRgammadelta(+) IELs and the deposition of IgM anti-TG2 antibodies in the jejunal mucosa of IgAD patients with and without CD. Immunohistochemical analyses for the number of CD3+ and TCRgammadelta(+) IELs and double immunofluorescence assay for IgM anti-TG2 antibody deposits were performed in biopsies from 25 children with IgAD (nine untreated CD, seven potential CD and nine without CD). Sixteen immunologically intact children without CD represented the controls. IgAD without CD had a higher number of CD3+ and TCRgammadelta(+) IELs than controls (P < 0.05), but lower than IgAD with CD (P < 0.01). No significant differences were noted between IgAD subjects without CD and those with potential CD. Furthermore, IgAD patients without CD showed a higher TCRgammadelta(+)/CD3+ ratio than the control group (P < 0.05), while the ratio was similar to subjects with CD and potential CD. Intestinal IgM anti-TG2 antibody deposits were present in six of seven of the IgAD patients with untreated CD, one of seven with potential CD and none of those without CD. Most of the patients with IgAD show immune activation in the jejunal mucosa. IgM anti-TG2 antibody deposits are present only in CD. Intestinal IgM anti-TG2 and immunohistochemical markers do not discriminate between IgAD and potential CD with IgAD. Therefore, the serum IgG CD-associated autoantibodies remains very important for the diagnosis of CD in IgAD.

An immunodominant DQ8 restricted gliadin peptide activates small intestinal immune response in in vitro cultured mucosa from HLA-DQ8 positive but not HLA-DQ8 negative coeliac patients

BACKGROUND

Studies on intestinal T cell clones from the mucosa of patients with coeliac disease have led to the identification of immunogenic gliadin epitopes. One is HLA-DQ8 restricted, its recognition by T cells being increased by introduction of negatively charged residues operated by tissue transglutaminase.

AIM

To test HLA-DQ8 restricted epitope in both native (QYPSGQGSFQPSQQNPQA) and deamidated (QYPSGEGSFQPSQENPQA) forms in an organ culture system of treated coeliac mucosa from HLA-DQ8 positive and HLA-DQ8 negative patients.

PATIENTS AND METHODS

Jejunal biopsies obtained from 10 patients with coeliac disease (six HLA-DQ8 positive and four HLA-DQ8 negative) were cultured in vitro with a peptic-tryptic digest (PT) of gliadin, or with the native (peptide A) or deamidated (peptide B) peptide. Intraepithelial CD3(+) and lamina propria total CD25(+) and CD3(+)CD25(+) cells were counted, lamina propria intercellular adhesion molecule 1 (ICAM-1) expression was evaluated, as well as that of Fas molecules on epithelial cells.

RESULTS

In HLA-DQ8 positive, but not in HLA-DQ8 negative, coeliacs the density of intraepithelial CD3(+) cells, lamina propria total CD25(+), and CD3(+)CD25(+) cells, as well as expression of ICAM-1 and Fas molecules were significantly increased in biopsies cultured with PT, peptide A, or peptide B compared with biopsies cultured in medium alone.

CONCLUSION

These data show that the DQ8 restricted gliadin peptide is immunogenic only in the intestinal mucosa of HLA-DQ8 positive coeliac patients in both native and deamidated forms.

Anti-tissue transglutaminase antibodies from coeliac patients inhibit transglutaminase activity both in vitro and in situ

BACKGROUND AND AIMS

Coeliac disease (CD) is a multifactorial disorder which has an autoimmune component characterised by the occurrence of disease specific autoreactive antibodies against the enzyme tissue transglutaminase (tTG). The aim of this study was to investigate whether binding of antibodies to the enzyme influences tTG activity.

METHODS

tTG activity was assayed in the presence of immunoglobulin A (IgA) and immunoglobulin G (IgG) purified from the serum of coeliac patients, CUB 7402 (an anti-tTG mouse monoclonal antibody), and human anti-tTG monoclonal antibodies derived from both intestinal lymphocytes from three patients with CD and from peripheral blood lymphocytes from healthy subjects. For our studies we used calcium treated and untreated recombinant human tTG. Furthermore, the effects of antibodies were determined by immunohistochemical detection of tTG activity in sections of human umbilical cord.

RESULTS

IgG and IgA from CD patients inhibited tTG activity in vitro in a dose dependent manner, with a different rate of inhibition among patients. The monoclonal antibody CUB 7402 and human monoclonal antibodies displayed a dose dependent inhibitory effect towards the catalytic activity of the enzyme, both in vitro and in situ. Preincubation of tTG with CaCl(2) caused loss of the inhibitory effect due to CUB 7402 but not that caused by human monoclonal antibodies.

CONCLUSIONS

Purified CD IgA, IgG, as well as human anti-tTG monoclonal antibodies inhibited the enzymatic activity of human tTG both in vitro and in situ.

The first large population based twin study of coeliac disease

BACKGROUND AND AIMS

The genetic load in coeliac disease has hitherto been inferred from case series or anecdotally referred twin pairs. We have evaluated the genetic component in coeliac disease by estimating the concordance rate for the disease among twin pairs in a large population based study.

METHODS

The Italian Twin Registry was matched with the membership lists of a patient support group. Forty seven twin pairs were recruited and screened for antiendomysial (EMA) and antihuman-tissue transglutaminase (anti-tTG) antibodies; zygosity was verified by DNA fingerprinting and twins were typed for HLA class II DRB1 and DQB1 molecules.

RESULTS

Concordance rates for coeliac disease differ significantly between monozygotic (MZ) (0.86 probandwise and 0.75 pairwise) and dizygotic (DZ) (0.20 probandwise and 0.11 pairwise) twins. This is the highest concordance so far reported for a multifactorial disease. A logistic regression model, adjusted for age, sex, number of shared HLA haplotypes, and zygosity, showed that genotypes DQA1*0501/DQB1*0201 and DQA1*0301/DQB1*0302 (encoding for heterodimers DQ2 and DQ8, respectively) conferred to the non-index twin a risk of contracting the disease of 3.3 and 1.4, respectively. The risk of being concordant for coeliac disease estimated for the non-index twin of MZ pairs was 17 (95% confidence interval 2.1-134), independent of the DQ at risk genotype.

CONCLUSION

This study provides substantial evidence for a very strong genetic component in coeliac disease, which is only partially due to the HLA region.

Immune response of the coeliac nasal mucosa to locally-instilled gliadin

We previously demonstrated a specific gluten-induced response in the rectal mucosa of coeliac patients. In the present study, we have evaluated the immune response to local gliadin challenge in the nasal mucosa of coeliac patients preliminary to exploring the feasibility of immune modulation by the nasal route. The local response to gliadin was evaluated on non-invasive scrapings of nasal mucosa. Cells harvested from the nasal scrapings of 21 coeliac patients and 12 healthy controls were counted after immunohistochemical staining. Six hours after gliadin challenge, the total number of cells was increased in coeliacs but not in controls. The increase was due principally to lymphoid cells and granulocytes. CD3+ cells doubled after gliadin challenge, but not after albumin control challenge. There was a similar rise in CD25+ cells, whereas the number of ICAM-expressing cells did not increase significantly. In control subjects, both gliadin and albumin induced a moderate but not significant increase in total cell number. In conclusion, the gliadin antigen provokes a mild inflammatory response in coeliac nasal mucosa.

Characterization of the inflammatory infiltrate in peptic oesophagitis

BACKGROUND

The diagnosis of oesophagitis is mainly based on histology, but interpretation of endoscopic biopsies is often difficult. We performed immunohistochemical studies on oesophageal biopsies to see if better characterization of the inflammatory cell infiltrate would improve the accuracy of the histologic diagnosis of gastro-oesophageal reflux disease.

METHODS

The study groups consisted of 40 consecutive children (mean age +/- SD: 79.6 +/- 5l.9 months; 20 boys) with gastro-oesophageal reflux disease and 7 symptomatic children (mean age +/- SD: 52.6 +/- 37.0 months; 3 boys) without gastro-oesophageal reflux disease. All patients underwent upper gastrointestinal endoscopy with oesophageal biopsies. The diagnosis of gastro-oesophageal reflux disease was established by conventional endoscopic and histologic criteria. In each mucosal biopsy specimen, the number of intraepithelial CD3+, CD25+ (IL2 receptor+), ICAM+, HLA-DR+ and mucosal mast cells were determined.

RESULTS

Conventional histology was in close agreement with endoscopic findings (p<0.001) and reflected the clinical score even more than endoscopic findings. Conventional histology significantly correlated with each inflammatory immunohistochemical marker (<0.05 for each), but the markers were not predictive of symptom severity. Immunohistochemical markers were always abnormal in the gastro-oesophageal reflux disease patients, even in the mildest cases of oesophagitis.

CONCLUSIONS

Although there is a good correlation between symptoms and histology, in a subset of patients, immunohistochemical studies appear useful in supporting the histological diagnosis of gastro-oesophageal reflux disease.

An immunocytochemical study of intrapancreatic ganglia, nerve fibres and neuroglandular junctions in Brockmann bodies of the tompot blenny (Blennius gattoruggine), a marine teleost

The innervation of the Brockmann bodies in the teleost fish, Blennius gattoruggine, was studied using immunocytochemical techniques at both the light and electron microscopy levels. Islet innervation consisted of intrapancreatic ganglia, generally localized inside the rim of the exocrine tissue of the Brockmann bodies, in proximity to the islet, nerve fibres and nerve terminals with synaptic complexes. The intrapancreatic ganglia were of variable size, with different numbers of ganglionic cells, that appeared unipolar in section. The cell bodies showed immunoreactivity to galanin, oxytocin, peptide tyrosine tyrosine and glucagon. The extrinsic and intrinsic nerve fibres passed through the exocrine parenchyma and crossed the connectival septa and islet connectival sheath, penetrating into the islets, where they became increasingly thinner. They terminated on the endocrine cells with dilated nerve terminals. At least three types of terminals were detected, depending on the different vesicle content: peptidergic, cholinergic or adrenergic. They presented specialized synaptic structures, the neuroglandular junctions, some of which contained neurosecretory granules immunogold labelled by galanin antiserum. This new finding confirms the role of galanin as a neurotransmitter. This rich supply of innervation may be important in the regulation and integration of islet secretion.

Organ culture of rectal mucosa : in vitro challenge with gluten in celiac disease

Celiac disease is sustained by an immunological process that mainly affects the jejunal mucosa (1). Nonetheless, jejunum is not the only site of the gastrointestinal tract that is involved in celiac disease. In recent years, Ensari and colleagues (2,3), by using immunohistochemical analysis and computerized image analysis for numerical quantitation, have significantly contributed to a definitive and clear demonstration of a celiac disease-associated "proctitis," and its gluten dependence. Morphometry has shown increased populations of plasma cells, lymphocytes, and mast cells in the rectal mucosa of untreated patients, with these changes being reverted, with the sole exception of mast cells, by dietary treatment (2). The immunohistochemical approach has demonstrated highly significant increases in CD3(+) and γδ(+) lymphocytes within both the lamina propria and the epithelium. Mononuclear cells, both lymphocytes (CD3(+)) and macrophages (CD68(+)) expressing interleukin-2 (IL-2) receptors (CD25(+)), have been found to be increased in the lamina propria, usually immediately below the basal lamina. Enterocytes have been noted to be positive for major histocompatibility complex class II display, a pattern usually absent in normal colon. Furthermore, increased expression of vascular cell adhesion molecule-1 (VCAM-1) molecules in the rectal mucosa of untreated, compared to either treated celiac rectum or control mucosae, has been reported (3). As a whole, these data suggest, analogously to jeunum, an ongoing T-cell-dependent, cell-mediated immune response in the rectal mucosa.

Morphological basis of the interactions between endocrine cell types in the pancreatic islets of the teleost, Blennius gattoruggine

The endocrine pancreas of the teleost fish Blennius gattoruggine was studied by immunochemistry using both light and electron microscopy. Generally, one large Brockmann body, along with intermediate and small islets, was found. Cells immunoreactive (IR) to anti-insulin (B), anti-glucagon (A) anti-somatostatin (D) anti-pancreatic polypeptide and anti-PYY sera were detected with B cells located at the center of the islet and the other cell types forming a peripheral mantle. The B-cell cytoplasm showed rows of microtubules close to the secretory granules and perpendicular to the plasmalemma. The ultrathin section images revealed exocytotic and endocytotic features, and the presence of intercellular gap junctions between the plasmalemma of contiguous cells, suggesting intercellular routes of communication, e.g. via autocrine and/or paracrine mechanism. These features were observed in all of the cell types, and were abundant in D cells. D cells were particularly numerous in the islets and were disposed close to A and B cells, as observed in other teleost species. The most peripheral B cells, in closer contact with D cells than the central ones, appeared strongly immunolabeled, perhaps owing to the inhibitory action of somatostatin. Some D cells exhibited a long protrusion directed towards the center of the islet. In view of their cytological characteristics and their secretion, D cells might have an important role in the modulation of A and B-cell secretion in an endocrine and/or paracrine fashion.

Maintenance of the differentiated type II cell phenotype by culture with an apical air surface

The study of differentiated functions of alveolar type II cells has been hampered because of the lack of good in vitro systems. We report that culture of type II cells on collagen gels with an apical surface exposed to air promotes expression of differentiated type II cell characteristics. Cells cultured in this manner are cuboidal, contain lamellar bodies, and produce tubular myelin; in addition, they secrete phosphatidylcholine in response to exogenous ATP. Cultures contain mRNA for surfactant proteins A, B, and C and surfactant proteins A, B, and D. In contrast, when type II cells are cultured with an apical surface exposed to liquid rather than to air, the cells are squamous, do not express surfactant proteins or their respective mRNA, and do not contain lamellar bodies or produce tubular myelin. Type II cells cultured on plastic for 7 days, which no longer express mRNA for surfactant proteins, can be induced to express these mRNA by changing culture conditions to that of an air surface. The culture system described in this paper should be useful for studies of surfactant metabolism, regulation of alveolar epithelial phenotypic expression, and the processing of transiently expressed transgenes.

Islets and diffuse endocrine component in the pancreas of three red frogs species: relationships between endocrine and exocrine tissue

The endocrine pancreas of three red frogs was studied immunohistochemically. It consisted of islets and diffuse endocrine cells. The islets showed a mammalian-like arrangement with a central core of B cells and a peripheral mantle of A/PP cells. A few D and VIP cells were also present. Several regulatory peptides were co-localized in the same endocrine cells by consecutive sections and double-labeling studies. The A/PP cells were formed by subpopulations of cells showing various types of immunoreactivity and varying degrees of immunolabeling. Generally, glucagon/pancreatic polypeptide, glucagon/pancreatic polypeptide/peptide tyrosine tyrosine and glucagon/pancreatic polypeptide/neuropeptide tyrosine immunoreactivities were present in the islets and in the endocrine cells scattered throughout the exocrine parenchyma (the diffuse component). Some specimens, mainly belonging to Rana dalmatina, showed evident periinsular halos around the islets. The diffuse component was abundant, and mainly contained A/PP cells. It formed a net across the exocrine parenchyma; its interrelationship with the latter might occur by a paracrine mechanism.

Trabecular meshwork cells grown on filters. Conductivity and cytochalasin effects

A system was developed to measure the hydraulic conductivity of cultured monolayers of human trabecular meshwork (HTM) cells. By optimizing the cell growth conditions and evaluating a number of filter supports, confluent HTM cells in single layers were obtained for measurement of hydraulic conductivity. The HTM monolayers had hydraulic conductivities of 0.3-2.0 microliters/min/mm Hg/cm2 measured at near-physiological flow rates. Evaluations of cytochalasin B (CB) effects on the hydraulic conductivity of our HTM monolayers revealed that CB (10(-6) to 10(-5) M) caused a dramatic dose-related increase in conductivity within 10 to 30 min, which parallels CB effects on outflow facility in vivo. Morphologic observations show that the increase in hydraulic conductivity was accompanied by a retraction of the trabecular cells and widening of the intercellular spaces. Our findings suggest that growth of HTM cells on filter supports can provide a useful in vitro system to study the regulation of aqueous outflow.

Pathogenesis of Chandler's syndrome, essential iris atrophy and the Cogan-Reese syndrome. I. Alterations of the corneal endothelium

Eight keratoplasty and 14 trabeculectomy specimens from Chandler's syndrome, Essential Iris Atrophy, and the Cogan-Reese syndrome were studied by electron microscopic and morphometric methods. The corneal endothelium in these conditions undergoes the most varied and complex alterations of any of the endotheliopathies so far studied. The size, shape, and density are altered, and the apical surface shows a myriad of abnormalities including alterations of the intercellular borders and junctions, and formation of numerous microvilli, filopodia, and "blebs." Whereas many cells have features indicative of metabolic activity, and others may have undergone division, still others appear to have been injured as they are disrupted and necrotic. There is also evidence for the presence of a low-grade, long-standing chronic inflammation and an associated loss of contact inhibition with formation of multiple endothelial layers. These changes do not encompass the entire endothelium, as some regions remain relatively unaffected, and each specimen presents a unique morphology. The endothelium is most affected in cases of Essential Iris Atrophy. Some changes may be related to such processes as cell migration and reparative activities. However, the presence of cell necrosis (apoptosis) and chronic inflammation (endotheliitis) may be more specifically related to the ICE syndrome endotheliopathy. The slit lamp and specular microscopy findings characteristic of this disease are correlated with the described histologic abnormalities.

Prenatal and postnatal cellularity of the human corneal endothelium. A quantitative histologic study

The authors studied the cellularity of the normal corneal endothelium by histologic methods in 56 specimens from 16 weeks of gestation to 98 years of age. Ten step-serial sections were taken from each specimen through the central 6 mm of the cornea, in an area measuring 1.8 mm. The number of nuclei were counted on each section and a ratio of the number of nuclei per 100 micron of endothelial length was determined. This ratio provides a measure of cell density that they call cellularity. There is a decrease in cellularity that proceeds in a nonlinear manner and at a very rapid rate during the prenatal period and for the first few years of life. Cell death or necrosis, which might have contributed to this apparent loss of cells, was not observed. Instead, this rapid change in cellularity is correlated with a concomitant change in corneal size. The authors' calculations show that cell division may play a minor role in the formation of the endothelium after the second trimester of fetal life as most of the cells present by birth already exist by this time. After the first few years of life, the rate of change in endothelial cellularity decreases to proceed in a linear manner for the rest of the near 100 years of life examined. This latter age-related decline in cellularity is probably due to the loss of 0.56% cells per year from the endothelial layer, since the cornea does not appear to change in size during this time. Statistical analysis of the authors' data shows that these results are highly significant.

Potential artifacts in scanning electron microscopy of the trabecular meshwork in glaucoma

We examined the trabecular meshwork surface by scanning electron microscopy to investigate possible artifacts appearing during collection and preparation of trabeculectomy specimens. As controls, trabecular tissue samples from normal and glaucomatous patients were dissected from whole eyes obtained at enucleation or at autopsy. Our results suggest that the major contaminants are released during decompression of the globe at trabeculectomy; these consist of an amorphous substance, a fibrillar material, and, occasionally, red blood cells. Small tissue samples may also abe contaminated by the conducting adhesive used to fasten them to metal stubs. This silver paint may coat the surface of the meshwork and appear to be a smooth substance blocking the outflow of aqueous humor. We were unable to confirm the finding reported by others that an amorphous blocking material is present in the trabecular interstices in patients with open-angle glaucoma.

The free surface of mouse trophoblast in culture is non-adhesive for other cells

Dispersed cells from cultured mouse cell lines, mouse macrophages, and inert microspheres were layered onto outgrowing mouse trophoblast in culture. The cells that settled onto the trophoblast remained round, in contrast to the elongated spreading shape they assumed on the glass substratum. The cells were readily dislodged from the trophoblast surface, whereas the microspheres were strongly adherent to trophoblast within 30 min. Scanning electron microscopy showed that trophoblast engulfed the spheres, but not the cells. Despite the lack of adhesion between cells and trophoblast, cell processes connected the two. The inability of cells to adhere to the free surface of the trophoblast could explain the trophoblast's ability to induce contact inhibition in co-cultured cells.

The ultrastructure of the endolymphatic sac in Ménière's disease

Meniere's disease is a well recognized clinical entity, yet the etiology and pathophysiology of the disease is not fully understood. Impaired endolymphatic sac function resulting in faulty reabsorption of endolymph has been implicated in the production of the disease. The histopathological findings from biopsied sac specimens and observed by transmission (TEM) and scanning (SEM) electronmicroscopy in two patients with early Meniere's disease are presented and discussed. Extensive subepithelial fibrosis with loss of vascularity and obliteration of portions of the lumen of the endolymphatic sac by an ingrowth of collagen is noted in both specimens. The implications of these findings are discussed and the need for more TEM and SEM studies of inner ear disorders is stressed.

Bacteria isolated from the duodenum, ileum, and cecum of young chicks

Facultatively anaerobic and strictly anaerobic bacteria colonizing the intestinal tracts of 14-day-old chicks fed a corn-based diet were enumerated, isolated, and identified. Colony counts from anaerobic roll tubes (rumen fluid medium) or aerobic plates (brain heart infusion agar) recovered from homogenates of the duodenum, upper and lower ileum, and cecum varied appreciably among samples from individual birds. Anaerobic and aerobic counts from the duodenum and ileum were similar. Anaerobic counts were highest from the cecum (0.7 X 10(11) to 1.6 X 10(11)/g of dry tissue) and exceeded aerobic plate counts by a factor of at least 10(2). Facultatively anaerobic groups (Streptococcus, Staphylococcus, Lactobacillus, and Escherichia coli) comprised the predominant flora of the duodenum and ileum, although large numbers of anaerobes (9 to 39% of the small intestine isolates), represented by species of Eubacterium, Propionibacterium, Clostridium, Gemmiger, and Fusobacterium, were also recovered. Strict anaerobes (anaerobic gram-positive cocci, Eubacterium, Clostridium Gemmiger, Fusobacterium, and Bacteriodes) made up nearly the entire microbial population of the cecum. Scanning electron microscopy of the intestinal epithelia of chicks revealed populations of microbes on the duodenal, ileal, and cecal mucosal surfaces.