Fabrizio Michetti

Adipose-Derived Mesenchymal Cells for Bone Regereneration: State of the Art

Adipose tissue represents a hot topic in regenerative medicine because of the tissue source abundance, the relatively easy retrieval, and the inherent biological properties of mesenchymal stem cells residing in its stroma. Adipose-derived mesenchymal stem cells (ASCs) are indeed multipotent somatic stem cells exhibiting growth kinetics and plasticity, proved to induce efficient tissue regeneration in several biomedical applications. A defined consensus for their isolation, classification, and characterization has been very recently achieved. In particular, bone tissue reconstruction and regeneration based on ASCs has emerged as a promising approach to restore structure and function of bone compromised by injury or disease. ASCs have been used in combination with osteoinductive biomaterial and/or osteogenic molecules, in either static or dynamic culture systems, to improve bone regeneration in several animal models. To date, few clinical trials on ASC-based bone reconstruction have been concluded and proved effective. The aim of this review is to dissect the state of the art on ASC use in bone regenerative applications in the attempt to provide a comprehensive coverage of the topics, from the basic laboratory to recent clinical applications.

Spinal Fusion in the Next Generation: Gene and Cell Therapy Approaches

Bone fusion represents a challenge in the orthopedics practice, being especially indicated for spine disorders. Spinal fusion can be defined as the bony union between two vertebral bodies obtained through the surgical introduction of an osteoconductive, osteoinductive, and osteogenic compound. Autogenous bone graft provides all these three qualities and is considered the gold standard. However, a high morbidity is associated with the harvest procedure. Intensive research efforts have been spent during the last decades to develop new approaches and technologies for successful spine fusion. In recent years, cell and gene therapies have attracted great interest from the scientific community. The improved knowledge of both mesenchymal stem cell biology and osteogenic molecules allowed their use in regenerative medicine, representing attractive approaches to achieve bone regeneration also in spinal surgery applications. In this review we aim to describe the developing gene- and cell-based bone regenerative approaches as promising future trends in spine fusion.

The S100B protein in biological fluids: more than a lifelong biomarker of brain distress

J. Neurochem. (2012) 120, 644–659.

S-100 antigen in satellite cells of the adrenal medulla and the superior cervical ganglion of the rat

SummaryMeasurable amounts of the nervous-system specific S-100 protein were detected by microcomplement fixation assay both in the superior cervical ganglion and in the adrenal medulla of adult rats, though at a significantly higher concentration in the ganglion. By the unlabeled antibody PAP method, the antigen was localized at: he ultrastructural level in the Schwann cells and in the satellite cells of the ganglion, but not in neurons. Similarly, the protein was found in the Schwann cells of the adrenal medulla, but not in the chromaffin cells. Moreover, the S-100 immunolabeling allowed detection of a class of “satellite” cells closely enveloping the chromaffin cells. In the labeled cells of both organs the reaction product was diffusely distributed in the cytoplasmic matrix as well as in the nucleoplasm.The presence of the S-100 antigen in the satellite cells of the sympathetic ganglion and in “satellite” cells of the adrenal medulla suggests a possible homology for the two cell types, and one could hypothesize the presence in peptide hormone-secreting endocrine organs of glia-like cells exhibiting functional relationships with the secretory cells comparable to those of the glial cells with the neurons.

The S-100 antigen in cerebrospinal fluid as a possible index of cell injury in the nervous system

The presence of the nervous system-specific S-100 antigen has been tested by microcomplement fixation assay with a monospecific anti-S-100 antiserum in cerebrospinal fluid (CSF) of subjects suffering from psychiatric disorders or various neurological diseases. The antigen was detectable in the CSF of most of the patients with neurological diseases characterized by an appreciable lesion in the nervous parenchyma, whereas it was generally absent from CSF of subjects presumably free from an extensive neurological lesion in the active phase. It is possible that the presence of S-100 IN CSF might be an index of active cell injury in the nervous parenchyma.

Immunochemical and immunocytochemical study of S-100 protein in rat adipocytes

S-100 is a protein originally believed to be unique to the nervous system. We report here on the presence of S-100 in rat adipocytes, using immunohistochemical and immunochemical methods. We demonstrate that the protein in adipose tissue is present at a concentration comparable to that measured in the nervous tissue and is immunologically identical to brain S-100, indicating that the protein can no longer be regarded as being specific to the nervous system.

Soluble and membrane-bound S-100 protein in cerebral cortex synaptosomes: Properties of the S-100 receptor

Within cerebral cortex synaptosomes, S-100 protein can be recovered in two forms: soluble and membrane-bound. Synaptosomal S-100 is mainly a soluble protein (85 percent). The membrane-bound S-100 is differently distributed in the synaptosomal membranes, intraterminal mitochondria, and synaptic vesicles. S-100 binds to a specific receptor. The binding is time-dependent, reversible and saturable with respect to S-100. The number of receptors is calculated to be about 9 times 10(12)/mg protein, since saturation is achieved at 31 ng [125I]S-100/0.1 mg protein of disrupted synaptosomes. The rate constant for association of S-100 with its receptor at 37 degrees C, k1, is 4.74 times 10(4) M(-1) sec(-1), and the rate constant for dissociation, k-1, 9.24 times 10(-4) sec(-1).

Pediatric Concentrations of S100B Protein in Blood: Age- and Sex-related Changes

The term S100 refers to members of a multigenic family of calcium-modulated proteins, mostly of low molecular mass (∼10 000 Da), first identified as a protein fraction detectable in the brain and called S100 because of its solubility in a solution of 100 g/L ammonium sulfate (1). The protein seems to be most abundant in glial cells, although its presence in neuronal subpopulations has also been reported (2)(3). The biological role of this protein within the cell populations that contain it has not been completely elucidated. The possibility of an extracellular biological role for S100B, which, secreted by astrocytes as a cytokine, may have a neurotrophic effect during both development and nerve regeneration at physiologic (nmol/L) concentrations, appears particularly interesting (4)(5)(6)(7). Recent studies conducted in perinatal medicine that showed a correlation between S100B protein measured in several biological fluids (i.e., amniotic fluid, cord blood, and urine) and gestational age (8)(9)(10) appear consistent with a neurotrophic role for the protein. The present study offers a reference curve for S100B protein in peripheral blood from the postnatal period to 15 years of age in healthy pediatric patients. Between April 1997 and July 2000, we routinely collected blood samples for S100B measurement from healthy children admitted to our Institute for routine day-hospital investigations. All of the children were delivered at term without perinatal complications, and their clinical history, from birth to the time of blood sampling, was negative for neurologic abnormalities and comorbidities. We recruited a total of 1004 healthy children (males, n = 482; females, n = 522) whose ages ranged from 1 month to 15 years of age (mean, 8 years). On admission to the study, all of the patients were checked against routine clinical and laboratory indices, …

Elevated S100 blood level as an early indicator of intraventricular hemorrhage in preterm infants. Correlation with cerebral Doppler velocimetry.

The aim of this study was to assess the use of S100 protein in blood as a means of identifying preterm infants at risk of intraventricular hemorrhage. In 25 preterm newborns, S100 blood concentrations were measured by an immunoradiometric assay during the first 48 h. Cerebral Doppler velocimetry waveform patterns were also tested at the time the blood sample was taken, when clinical and cerebral ultrasound scanning were still normal. Of the 25 newborns studied, 14 were controls and 11 developed intraventricular hemorrhage as revealed by ultrasound scanning more than 72 h after birth, and clinically confirmed by neurological examination on the seventh day of follow-up. S100 blood concentrations were significantly higher (P<0.002) in infants with intraventricular hemorrhage than in control infants and also correlated significantly (r=0.81, P<0.003) with the grade of hemorrhage. A significant correlation (r=0.70, P<0.05) between the S100 blood concentration and the middle cerebral artery pulsatility index was also observed. The present data show that S100 blood concentrations offer a measurable parameter of brain lesion in preterm infants before a radiological assessment of hemorrhage can be performed, when clinical symptoms may be silent and preventive/therapeutic action could be especially useful.

The nervous system-specific S-100 antigen in cerebrospinal fluid of multiple sclerosis patients.

The nervous system-specific S-100 antigen has been found in cerebrospinal fluid (CSF) of 13 out of 18 patients with multiple sclerosis (MS), whereas it was undetectable in either of the 11 control patients with minor psychic disturbances or with neurological disorders not usually associated with apparent parenchymal lesion. The levels of the antigen appeared to be higher in CSF of patients in the acute phase of the disease. Though the small number of cases hampers final statements, the S-100 in CSF might serve as a possible index of active cell injury in the central nervous system underlying the pathogenesis of MS.