Thymic Epithelium Abnormalities in DiGeorge and Down Syndrome Patients Contribute to Dysregulation in T Cell Development

The thymus plays a fundamental role in establishing and maintaining central and peripheral tolerance and defects in thymic architecture or AIRE expression result in the development of autoreactive lymphocytes. Patients with partial DiGeorge Syndrome (pDGS) and Down Syndrome (DS) present alterations in size and architecture of the thymus and higher risk to develop autoimmunity. We sought to evaluate thymic architecture and thymocyte development in DGS and DS patients and to determine the extent to which thymic defects result in immune dysregulation and T cell homeostasis perturbation in these patients. Thymi from pediatric patients and age-matched controls were obtained to evaluate cortex and medullary compartments, AIRE expression and thymocyte development. In the same patients we also characterized immunophenotype of peripheral T cells. Phenotypic and functional characterization of thymic and peripheral regulatory T (Treg) cells was finally assessed. Histologic analysis revealed peculiar alterations in thymic medulla size and maturation in DGS and DS patients. Perturbed distribution of thymocytes and altered thymic output was also observed. DGS patients showed lower mature CD4⁺ and CD8⁺ T cell frequency, associated with reduced proportion and function of Tregs both in thymus and peripheral blood. DS patients showed increased frequency of single positive (SP) thymocytes and thymic Treg cells. However, Tregs isolated both from thymus and peripheral blood of DS patients showed reduced suppressive ability. Our results provide novel insights on thymic defects associated with DGS and DS and their impact on peripheral immune dysregulation. Indeed, thymic abnormalities and defect in thymocyte development, in particular in Treg cell number and function could contribute in the pathogenesis of the immunodysregulation present in pDGS and in DS patients.

Acquired coronary artery disease in adult patients with congenital heart disease: a true or a false problem?

BACKGROUND

The population of adults with congenital heart disease (ACHD) is increasing and aging, and a large percentage of this population is now over 65 years of age. For this reason, it is probable that acquired coronary artery disease (CAD) will become an important issue that needs to be addressed also in these patients. We retrospectively analyzed all ACHD patients who underwent surgery in our Institution with the aim to investigate the incidence of associated CAD and the results of surgical treatment.

METHODS

From January 2000 to December 2015, a total of 1154 ACHD underwent surgery in our center. Fifty patients (4.3%) were diagnosed with acquired CAD and required coronary artery bypass grafting. The mean age at surgery was 66 years (range 41-78 years). The primary diagnosis were atrial septal defect (n = 40 patients), Tetralogy of Fallot (n = 4 patients), ventricular septal defect (n = 2 patients), partial AV canal (n = 1), partial anomalous pulmonary venous drainage (n = 1), Ebstein's anomaly (n = 1), and subaortic stenosis (n = 1).

RESULTS

Hospital mortality was 2% (one patient). During a mean follow-up of 9 years (maximum follow-up: 15 years), seven patients died (14%). The actuarial survival was 83% at 5 years and 77% at 10 years. Freedom from reoperation for coronary artery bypass grafting or percutaneous coronary intervention was 88% at 5 years and 82% at 10 years.

CONCLUSION

Acquired CAD may coexist with congenital heart defects but the association is quite rare. It typically occurs later during adulthood and it is usually associated with atrial septal defect. Acquired CAD and congenital heart defects can be treated contemporarily with good early and late results.

S100B maternal blood levels are gestational age- and gender-dependent in healthy pregnancies

BACKGROUND

S100B is a well-established biomarker of central nervous system (CNS) development and damage in the perinatal period. Because the fetal CNS induces an overproduction of S100B measurable in the maternal bloodstream we evaluated S100B protein in healthy pregnancies in order to provide a reference curve of the protein in the second and third trimesters and to provide information on CNS development when standard monitoring procedures could be silent or unavailable.

METHODS

Between July 2012 and December 2014 we conducted a prospective study in 1213 healthy pregnancies delivering healthy newborns. Maternal blood samples were collected for standard monitoring procedures and S100B assessment. S100B correlations with selected outcomes (gestational age at sampling, gender of fetus, gestational age and weight at birth, delivery mode) were calculated using multiple forward stepwise regression analysis.

RESULTS

S100B concentrations in the second and third trimesters of pregnancy were found to be gestational age-, gender- and delivery mode-dependent (p<0.05, for all). Multiple forward stepwise regression analysis with S100B as the dependent variable and gestational age at sampling, gender, delivery mode, gestational age and weight at birth as independent variables, showed a significant correlation between S100B and gestational age at sampling (R=0.13; p<0.001).

CONCLUSIONS

The present findings offering a S100B protein reference curve in maternal blood suggest that non-invasive fetal CNS monitoring is becoming feasible and open the way to further research in neuro-biomarker assessment in the maternal bloodstream.

Percutaneous management of failed bioprosthetic pulmonary valves in patients with congenital heart defects

AIMS

We reviewed our center experience in the field of transcatheter pulmonary valve-in-valve implantation (TPViV), that is emerging as a treatment option for patients with pulmonary bioprosthetic valve (BPV) dysfunction.

METHODS

Between April 2008 and September 2015, a total of six patients with congenital heart disease (four men) underwent TPViV due to stenosis of preexisting BPV. Four patients received a Melody Medtronic Transcatheter Pulmonary Valve and two an Edward Sapien Valve.

RESULTS

No procedural-related complications occurred. After valve implantation, right ventricular systolic pressure (RVSP, 80.5 ± 25.3-41.2 ± 8.35 mmHg, P < 0.05), right ventricular outflow tract (RVOT) gradient (55.3 ± 23.4-10.6 ± 3.8 mmHg, P < 0.05), and RVSP-to-aortic pressure (0.75 ± 0.21-0.38 ± 0.21, P = 0.01) fell significantly. Echocardiograms at follow-up revealed a significant reduction in estimated RVSP (88.7 ± 22-21.7 ± 4.7 mmHg, P < 0.05), in RVOT (76.2 ± 17.9-25.7 ± 6.1 mmHg, P = 0.005), and in mean RVOT (40.7 ± 9.9-15.5 ± 4.8 mmHg, P < 0.05) gradients. Cardiac magnetic resonance showed no significant change in biventricular dimensions and function. Symptomatic patients reported improvement of symptoms, although cardiopulmonary exercise did not show any significant differences.

CONCLUSION

TPViV is an effective and well tolerated treatment for BPV dysfunction, improving freedom from surgical reintervention. Long-term studies will redefine the management of dysfunctional RVOT, either native or surrogate.

Gangliosides as a potential new class of stem cell markers: the case of GD1a in human bone marrow mesenchymal stem cells

Owing to their exposure on the cell surface and the possibility of being directly recognized with specific antibodies, glycosphingolipids have aroused great interest in the field of stem cell biology. In the search for specific markers of the differentiation of human bone marrow mesenchymal stem cells (hBMSCs) toward osteoblasts, we studied their glycosphingolipid pattern, with particular attention to gangliosides. After lipid extraction and fractionation, gangliosides, metabolically (3)H-labeled in the sphingosine moiety, were separated by high-performance TLC and chemically characterized by MALDI MS. Upon induction of osteogenic differentiation, a 3-fold increase of ganglioside GD1a was observed. Therefore, the hypothesis of GD1a involvement in hBMSCs commitment toward the osteogenic phenotype was tested by comparison of the osteogenic propensity of GD1a-highly expressing versus GD1a-low expressing hBMSCs and direct addition of GD1a in the differentiation medium. It was found that either the high expression of GD1a in hBMSCs or the addition of GD1a in the differentiation medium favored osteogenesis, providing a remarkable increase of alkaline phosphatase. It was also observed that ganglioside GD2, although detectable in hBMSCs by immunohistochemistry with an anti-GD2 antibody, could not be recognized by chemical analysis, likely reflecting a case, not uncommon, of molecular mimicry.

Isolation and characterization of 2 new human rotator cuff and long head of biceps tendon cells possessing stem cell-like self-renewal and multipotential differentiation capacity

BACKGROUND

Stem cell therapy is expected to offer new alternatives to the traditional therapies of rotator cuff tendon tears. In particular, resident, tissue-specific, adult stem cells seem to have a higher regenerative potential for the tissue where they reside.

HYPOTHESIS

Rotator cuff tendon and long head of the biceps tendon possess a resident stem cell population that, when properly stimulated, may be induced to proliferate, thus being potentially usable for tendon regeneration.

STUDY DESIGN

Controlled laboratory study.

METHODS

Human tendon samples from the supraspinatus and the long head of the biceps were collected during rotator cuff tendon surgeries from 26 patients, washed with phosphate-buffered saline, cut into small pieces, and digested with collagenase type I and dispase. After centrifugation, cell pellets were resuspended in appropriate culture medium and plated. Adherent cells were cultured, phenotypically characterized, and then compared with human bone marrow stromal cells (BMSCs), as an example of adult stem cells, and human dermal fibroblasts, as normal proliferating cells with no stem cell properties.

RESULTS

Two new adult stem cell populations from the supraspinatus and long head of the biceps tendons were isolated, characterized, and cultured in vitro. Cells showed adult stem cell characteristics (ie, they were self-renewing in vitro, clonogenic, and multipotent), as they could be induced to differentiate into different cell types--namely, osteoblasts, adipocytes, and skeletal muscle cells.

CONCLUSION

This work demonstrated that human rotator cuff tendon stem cells and human long head of the biceps tendon stem cells can be isolated and possess a high regenerative potential, which is comparable with that of BMSCs. Moreover, comparative analysis of the sphingolipid pattern of isolated cells with that of BMSCs and fibroblasts revealed the possibility of using this class of lipids as new possible markers of the cell differentiation status.

CLINICAL RELEVANCE

Rotator cuff and long head of the biceps tendons contain a stem cell population that can proliferate in vitro and could constitute an easily accessible stem cell source to develop novel therapies for tendon regeneration.

NEU3 sialidase is activated under hypoxia and protects skeletal muscle cells from apoptosis through the activation of the epidermal growth factor receptor signaling pathway and the hypoxia-inducible factor (HIF)-1α

NEU3 sialidase, a key enzyme in ganglioside metabolism, is activated under hypoxic conditions in cultured skeletal muscle cells (C2C12). NEU3 up-regulation stimulates the EGF receptor signaling pathway, which in turn activates the hypoxia-inducible factor (HIF-1α), resulting in a final increase of cell survival and proliferation. In the same cells, stable overexpression of sialidase NEU3 significantly enhances cell resistance to hypoxia, whereas stable silencing of the enzyme renders cells more susceptible to apoptosis. These data support the working hypothesis of a physiological role played by NEU3 sialidase in protecting cells from hypoxic stress and may suggest new directions in the development of therapeutic strategies against ischemic diseases, particularly of the cerebro-cardiovascular system.

Reversine increases multipotent human mesenchymal cells differentiation potential

Among different human stem cell sources, adult mesenchymal stem cells from bone marrow (BMSCs), and more recently from adipose tissues (ASCs), have shown their capability to differentiate into a variety of different cell types, including osteoblasts, adipocytes, and muscle cells. However, mesenchymal stem cell differentiation toward certain cell types (including skeletal and cardiac muscle), while shown to be achievable, still suffers of low yields and needs to be greatly improved before any therapeutic application could be foreseen. A possible way of achieving this goal is by using a chemical-pharmacological approach to increase stem cell plasticity. Along this line, we envisioned the possibility of pre-treating BMSCs and ASCs with reversine, a synthetic purine that has been shown to induce adult cells de-differentiation. In the current study we tested reversine effects on both BMSCs and ASCs to increase their differentiation toward osteoblasts, smooth and skeletal muscle cells. Reversine pre-treatment, at very low concentration (50 nM), caused a marked increase in the differentiation yields of both BMSCs and ASCs.

Nitric oxide synthase-dependent NADPH-diaphorase activity in the optic lobes of male and female Ceratitis capitata mutants

Nitric oxide (NO) is acknowledged as a messenger molecule in the nervous system with a pivotal role in the modulation of the chemosensory information. It has been shown to be present in the optic lobes of several insect species. In the present study, we used males and females from four different strains of the medfly Ceratitis capitata (Diptera, Tephritidae): or; or,wp (both orange eyed); w,M360 and w,Heraklion (both white eyed), as models to further clarify the involvement of NO in the mutants' visual system and differences in its activity and localization in the sexes. Comparison of the localization pattern of NO synthase (NOS), through NADPH-diaphorase (NADPHd) staining, in the optic lobes of the four strains, revealed a stronger reaction intensity in the retina and in the neuropile region lamina than in medulla and lobula. Interestingly, the intensity of NADPHd staining differs, at least in some strains, in the optic lobes of the two sexes; all the areas are generally strongly labelled in the males of the or and w,M360 strains, whereas the w,Heraklion and or,wp mutants do not show evident sex-dependent NADPHd staining. Taken as a whole, our data point to NO as a likely transmitter candidate in the visual information processes in insects, with a possible correlation among NOS distribution, eye pigmentation and visual function in C. capitata males. Moreover, NO could influence behavioural differences linked to vision in the two sexes.

NEU3 sialidase strictly modulates GM3 levels in skeletal myoblasts C2C12 thus favoring their differentiation and protecting them from apoptosis

Membrane-bound sialidase NEU3, often referred to as the "ganglioside sialidase," has a critical regulatory function on the sialoglycosphingolipid pattern of the cell membrane, with an anti-apoptotic function, especially in cancer cells. Although other sialidases have been shown to be involved in skeletal muscle differentiation, the role of NEU3 had yet to be disclosed. Herein we report that NEU3 plays a key role in skeletal muscle differentiation by strictly modulating the ganglioside content of adjacent cells, with special regard to GM3. Induced down-regulation of NEU3 in murine C2C12 myoblasts, even when partial, totally inhibits their capability to differentiate by increasing the GM3 level above a critical point, which causes epidermal growth factor receptor inhibition (and ultimately its down-regulation) and an higher responsiveness of myoblasts to the apoptotic stimuli.

Gastrin-cholecystokinin immunoreactivity in the central nervous system of Helix aspersa during rest and activity

The immunostaining pattern for the peptide gastrin/cholecystokinin 8 (gastrin/CCK8) in the molluscan central nervous system has been considered. The changes in the distribution of gastrin/CCK8 immunoreactivity were analyzed in the neurons of different areas of the cerebral ganglia (mesocerebrum and metacerebrum) and in the buccal ganglia of the terrestrial snail Helix aspersa, during rest and active phases. During the period of inactivity and after one day of activity, there were several immunoreactive neurons in the mesocerebrum and metacerebrum of the snails and in the buccal ganglia, whereas after 7 days of activity the number of labeled neurons decreased. Data suggested a storage of gastrin/CCK8 in the neurons when behavioral activities in which the peptide is involved (such as feeding-related behavior) are suppressed or reduced. The different percentage of gastrin/CCK8 immunoreactive neurons in the left and right mesocerebrum provides information about the activities controlled by these neurons, which could be related to the adaptive evolution and plasticity of the brain in terrestrial pulmonates.

Mature and developing visual system of Ceratitis capitata (Diptera, Tephritidae): histochemical evidence of nitric oxide synthase in the wild type and the white eye mutant strains

Nitric oxide (NO) is acknowledged as a messenger molecule in the nervous system. It has a role in the modulation of the chemosensory information and seems implicated also in visual processes and visually guided behaviour of some insects. In the present study, we used two different strains of the medfly Ceratitis capitata (Diptera, Tephritidae), a wild type eye colour and a white eye mutant line, as models to clarify the involvement of NO in the mature and developing visual system. The comparison between the pattern of enzyme histochemical localization of NO synthase (NOS), through NADPH diaphorase (NADPHd) staining, in the optic lobes of the two strains revealed for adults a stronger intensity of reaction in all the neuropiles and the sub-retinic monopolar cell layer of the wild type flies, with respect to the white eye mutant correspondent areas. Anti-NOS immunocytochemistry correlated with these results, underlying reactivity both in fine fibres and varicosities and in cell bodies and supporting the idea of presence of NOS also in the retina of the medfly optic lobes. NADPHd reactivity was present in the first developmental stages of the white eye mutant also, but at lower intensity than wild type, and it decreased in some areas during the transition to adult fly stage both in the wild type and in the white eye mutant. All these observations together indicate that changes in the NO system of C. capitata could be related to the visual information processing, when the visual response or discrimination are altered. Furthermore, NO may be involved in the establishment of the retinal projection pattern and in the control of optic lobes morphogenesis.

Nitric oxide-containing neurons in the nervous ganglia of Helix aspersa during rest and activity: immunocytochemical and enzyme histochemical detection

Nitric oxide synthase (NOS) immunoreactivity and staining for nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-diaphorase) activity are two cytochemical markers for nitric oxide (NO)-containing neurons. The authors examined the changes in the distribution of NOS immunolabeling and NADPH-diaphorase reactivity in the cerebral and buccal ganglia of the terrestrial snail Helix aspersa during resting and active phases. During inactivity and after 1 day of activity, in the mesocerebrum and metacerebrum of the snails, there were several reactive neurons for both markers; after 7 days of activity, the number of reactive neurons was lower. Opposite results were obtained in the buccal ganglia, in which increased staining and numbers of reactive neurons were present in the active snails (after 1 day and 7 days of activity). Although the staining patterns for the two reactions were similar, colocalization was not always observed. The comparison between inactive and active animals provided a more precise survey of NOS-containing neurons in the snail cerebral ganglia than previously described. Moreover, it suggested that not only is NO involved in distinct nervous circuits, but, as a ubiquitous molecule, it also plays a role in neuroprotection and neuropeptide release.

Asymmetric alignment-stabilized external-cavity semiconductor laser

We have demonstrated an alignment-stabilized asymmetric cavity configuration for a grating-tuned externalcavity semiconductor laser. The grating in the asymmetric cavity has a 16-fold greater angular misalignment tolerance than in a conventional symmetric external-cavity semiconductor laser. The tuning ranges are nearly the same for both cavities (approximately 30 nm).