From pseudohypoparathyroidism to inactivating PTH/PTHrP signalling disorder (iPPSD), a novel classification proposed by the EuroPHP network.

OBJECTIVE: Disorders caused by impairments in the parathyroid hormone (PTH) signalling pathway are historically classified under the term pseudohypoparathyroidism (PHP), which encompasses rare, related and highly heterogeneous diseases with demonstrated (epi)genetic causes. The actual classification is based on the presence or absence of specific clinical and biochemical signs together with an in vivo response to exogenous PTH and the results of an in vitro assay to measure Gsa protein activity. However, this classification disregards other related diseases such as acrodysostosis (ACRDYS) or progressive osseous heteroplasia (POH), as well as recent findings of clinical and genetic/epigenetic background of the different subtypes. Therefore, the EuroPHP network decided to develop a new classification that encompasses all disorders with impairments in PTH and/or PTHrP cAMP-mediated pathway. DESIGN AND METHODS: Extensive review of the literature was performed. Several meetings were organised to discuss about a new, more effective and accurate way to describe disorders caused by abnormalities of the PTH/PTHrP signalling pathway. RESULTS AND CONCLUSIONS: After determining the major and minor criteria to be considered for the diagnosis of these disorders, we proposed to group them under the term 'inactivating PTH/PTHrP signalling disorder' (iPPSD). This terminology: (i) defines the common mechanism responsible for all diseases; (ii) does not require a confirmed genetic defect; (iii) avoids ambiguous terms like 'pseudo' and (iv) eliminates the clinical or molecular overlap between diseases. We believe that the use of this nomenclature and classification will facilitate the development of rationale and comprehensive international guidelines for the diagnosis and treatment of iPPSDs.

Angiogenic and anti-inflammatory properties of mesenchymal stem cells from cord blood: soluble factors and extracellular vesicles for cell regeneration.

In a recent work, our group showed the existence of two distinct mesenchymal stem cell (MSC) subsets within human umbilical cord blood. One less proliferative and short-living (SL-CBMSC), the other with higher growth rate and long-living (LL-CBMSC), and therefore better suited for regenerative medicine applications. We examined whether LL-CBMSC possess peculiar paracrine properties able to affect angiogenesis or inflammatory processes. It was shown for the first time that pro-angiogenic, proliferation-stimulating and tissue repairing factors were released at high level not only as soluble cytokines, but also as mRNA precursors embedded in membrane vesicles. The combination of this primary (proteic factors interacting with surface receptors) and delayed (mRNA transferred and translated via vesicle fusion and cargo release) interaction in endothelial target cells resulted in strong blood vessel induction with the development of capillary-like structures. In addition, LL-CBMSC dynamically modulated their release of pro-angiogenic and anti-inflammatory factors in an in vitro model of damage. In conclusion, LL-CBMSC synthesize and secrete multiple factors that may be attuned in response to the status of the target cell, a crucial requisite when paracrine mechanisms are needed at onset of tissue regeneration.

A Chemically Defined Medium-Based Strategy to Efficiently Generate Clinically Relevant Cord Blood Mesenchymal Stromal Colonies.

During the last decade it has been demonstrated that mesenchymal progenitors are present and can be isolated also from cord blood (CB). Recently, we managed to set up a standard protocol allowing the isolation of mesenchymal stromal cells (MSCs) with high proliferative potential and multiple differentiation capabilities, whereas the generation rate of MSC-initiating colonies could still be further improved. Herein, we strikingly succeeded in defining some simple and basic culture conditions based on the use of a chemically defined medium that increased the colony isolation efficiency up to almost 80% of processed CB units. Importantly, this result was achieved irrespective of CB unit white blood cell content and time elapsed from delivery, two limiting parameters involved with processing CB units. Thus, this high efficiency is guaranteed without strict selection of the starting material. In addition, since we are profoundly concerned about how different culture conditions can influence cell behavior, we devoted part of this study to in-depth characterization of the established CB-MSC populations to confirm their stemness features in this novel isolation and culture system. Therefore, an extended study of their immunophenotype, including classical pericytic markers, and a detailed molecular analysis addressing telomere length and also stemness-related microRNA contribution were performed. In summary, we propose a straightforward, extremely efficient, and reliable approach to isolate and expand thoroughly characterized CB-MSCs, even when poor-quality CB units are the only available source, or there is no space for an isolation to fail.

Screening of PRKAR1A and PDE4D in a Large Italian Series of Patients Clinically Diagnosed With Albright Hereditary Osteodystrophy and/or Pseudohypoparathyroidism.

The cyclic adenosine monophosphate (cAMP) intracellular signaling pathway mediates the physiological effects of several hormones and neurotransmitters, acting by the activation of G-protein coupled receptors (GPCRs) and several downstream intracellular effectors, including the heterotrimeric stimulatory G-protein (Gs), the cAMP-dependent protein kinase A (PKA), and cAMP-specific phosphodiesterases (PDEs). Defective G-protein-mediated signaling has been associated with an increasing number of disorders, including Albright hereditary osteodistrophy (AHO) and pseudohypoparathyroidism (PHP), a heterogeneous group of rare genetic metabolic disorders resulting from molecular defects at the GNAS locus. Moreover, mutations in PRKAR1A and PDE4D genes have been recently detected in patients with acrodysostosis (ACRDYS), showing a skeletal and endocrinological phenotype partially overlapping with AHO/PHP. Despite the high detection rate of molecular defects by currently available molecular approaches, about 30% of AHO/PHP patients still lack a molecular diagnosis, hence the need to screen patients negative for GNAS epi/genetic defects also for chromosomal regions and genes associated with diseases that undergo differential diagnosis with PHP. According to the growing knowledge on Gsα-cAMP signaling-linked disorders, we investigated our series of patients (n = 81) with a clinical diagnosis of PHP/AHO but negative for GNAS anomalies for the presence of novel genetic variants at PRKAR1A and PDE4D genes. Our work allowed the detection of 8 novel missense variants affecting genes so far associated with ACRDYS in 9 patients. Our data further confirm the molecular and clinical overlap among these disorders. We present the data collected from a large series of patients and a brief review of the literature in order to compare our findings with already published data; to look for PRKAR1A/PDE4D mutation spectrum, recurrent mutations, and mutation hot spots; and to identify specific clinical features associated with ACRDYS that deserve surveillance during follow-up. © 2016 American Society for Bone and Mineral Research.

Extensive Characterization of Platelet Gel Releasate From Cord Blood in Regenerative Medicine.

Platelet gel derived from peripheral blood is widely applied in many clinical fields of surgery as biomaterial containing growth factors with high proliferative properties. In 2010, we studied and patented a platelet gel derived from cord blood. In this study, due to the crucial role of the factors released by the platelet gel, we first extended the characterization of its releasate. Using a wide proteomic array and splitting the two components of the releasate, that is, platelets and plasma, we have been able to study their growth factor content. Interestingly, we discovered high levels of hormones and molecules able to support tissue growth in the cord blood platelet gel releasate and, in addition, higher concentrations of several angiogenic factors if compared with the peripheral blood counterpart. On the contrary, the latter was much richer in inflammatory factors. The second aim of our work was to study the effects on cell culture, immunophenotype, and function of mesenchymal stem cells exposed to these two platelet gel releasates as substitute for the animal serum. Since our findings nicely show that the use of the peripheral versus the cord blood platelet gel releasate can differently influence the mesenchymal stem cell commitment, we can suggest that in addition to its peculiar angiogenic properties cord blood platelet gel releasate shows excellent proliferative properties as cell culture supplement.

Dissection of the cord blood stromal component reveals predictive parameters for culture outcome.

In regenerative medicine, human cord blood-derived multipotent mesenchymal stromal cells (CBMSCs) stand out for their biological peculiarities demonstrated in in vitro and in vivo preclinical studies. Here, we present our 9-year experience for the consistent isolation of CBMSCs. Although nearly one CB unit out of two retains the potential to give rise to MSC colonies, only 46% of them can be cultured till low passages (P≥4), but one-fourth of those reaches even higher passages (P≥8). Subsequent characterization for morphological, clonal, differentiation, and proliferation properties revealed two divergent CBMSC behaviors. In particular, a cumulative population doublings cut-off (CPD=15) was identified that undoubtedly distinguishes two growth curves, and different degrees of commitment toward osteogenesis were observed. These data clearly show the existence of at least two distinct CBMSC subsets: one mainly short-living and less proliferative (SL-CBMSCs), the other long-living, with higher growth rate, and, very importantly, with significantly (P≤0.01) longer telomere (LL-CBMSCs). Moreover, significant differences in the immunoprofile before seeding were found among CB units giving rise to LL-CBMSCs or SL-CBMSCs or showing no colony formation. Finally, all the aforementioned results provided a peculiar and useful set of parameters potentially predictive for CBMSC culture outcome.

Autologous mesenchymal stem cell therapy for progressive supranuclear palsy: translation into a phase I controlled, randomized clinical study.

BACKGROUND: Progressive Supranuclear Palsy (PSP) is a sporadic and progressive neurodegenerative disease which belongs to the family of tauopathies and involves both cortical and subcortical structures. No effective therapy is to date available. METHODS/DESIGN: Autologous bone marrow (BM) mesenchymal stem cells (MSC) from patients affected by different type of parkinsonisms have shown their ability to improve the dopaminergic function in preclinical and clinical models. It is also possible to isolate and expand MSC from the BM of PSP patients with the same proliferation rate and immuphenotypic profile as MSC from healthy donors. BM MSC can be efficiently delivered to the affected brain regions of PSP patients where they can exert their beneficial effects through different mechanisms including the secretion of neurotrophic factors.Here we propose a randomized, placebo-controlled, double-blind phase I clinical trial in patients affected by PSP with MSC delivered via intra-arterial injection. DISCUSSION: To our knowledge, this is the first clinical trial to be applied in a no-option parkinsonism that aims to test the safety and to exploit the properties of autologous mesenchymal stem cells in reducing disease progression. The study has been designed to test the safety of this "first-in-man" approach and to preliminarily explore its efficacy by excluding the placebo effect. TRIAL REGISTRATION: NCT01824121.

Blood-brain barrier alterations in the cerebral cortex in experimental autoimmune encephalomyelitis.

The pathophysiology of cerebral cortical lesions in multiple sclerosis (MS) is not understood. We investigated cerebral cortex microvessels during immune-mediated demyelination in the MS model chronic murine experimental autoimmune encephalomyelitis (EAE) by immunolocalization of the endothelial cell tight junction (TJ) integral proteins claudin-5 and occludin, a structural protein of caveolae, caveolin-1, and the blood-brain barrier-specific endothelial transporter, Glut 1. In EAE-affected mice, there were areas of extensive subpial demyelination and well-demarcated lesions that extended to deeper cortical layers. Activation of microglia and absence of perivascular inflammatory infiltrates were common in these areas. Microvascular endothelial cells showed increased expression of caveolin-1 and a coincident loss of both claudin-5 and occludin normal junctional staining patterns. At a very early disease stage, claudin-5 molecules tended to cluster and form vacuoles that were also Glut 1 positive; the initially preserved occludin pattern became diffusely cytoplasmic at more advanced stages. Possible internalization of claudin-5 on TJ dismantling was suggested by its coexpression with the autophagosomal marker MAP1LC3A. Loss of TJ integrity was confirmed by fluorescein isothiocyanate-dextran experiments that showed leakage of the tracer into the perivascular neuropil. These observations indicate that, in the cerebral cortex of EAE-affected mice, there is a microvascular disease that differentially targets claudin-5 and occludin during ongoing demyelination despite only minimal inflammation.

Neuroprotective effects of toll-like receptor 4 antagonism in spinal cord cultures and in a mouse model of motor neuron degeneration.

Sustained inflammatory reactions are common pathological events associated with neuron loss in neurodegenerative diseases. Reported evidence suggests that Toll-like receptor 4 (TLR4) is a key player of neuroinflammation in several neurodegenerative diseases. However, the mechanisms by which TLR4 mediates neurotoxic signals remain poorly understood. We investigated the role of TLR4 in in vitro and in vivo settings of motor neuron degeneration. Using primary cultures from mouse spinal cords, we characterized both the proinflammatory and neurotoxic effects of TLR4 activation with lipopolysaccharide (activation of microglial cells, release of proinflammatory cytokines and motor neuron death) and the protective effects of a cyanobacteria-derived TLR4 antagonist (VB3323). With the use of TLR4-deficient cells, a critical role of the microglial component with functionally active TLR4 emerged in this setting. The in vivo experiments were carried out in a mouse model of spontaneous motor neuron degeneration, the wobbler mouse, where we preliminarily confirmed a protective effect of TLR4 antagonism. Compared with vehicle- and riluzole-treated mice, those chronically treated with VB3323 showed a decrease in microglial activation and morphological alterations of spinal cord neurons and a better performance in the paw abnormality and grip-strength tests. Taken together, our data add new understanding of the role of TLR4 in mediating neurotoxicity in the spinal cord and suggest that TLR4 antagonists could be considered in future studies as candidate protective agents for motor neurons in degenerative diseases.