Nanostructured TiO₂ Surfaces Promote Human Bone Marrow Mesenchymal Stem Cells Differentiation to Osteoblasts

Micro- and nano-patterning/modification are emerging strategies to improve surfaces properties that may influence critically cells adherence and differentiation. Aim of this work was to study the in vitro biological reactivity of human bone marrow mesenchymal stem cells (hBMSCs) to a nanostructured titanium dioxide (TiO₂) surface in comparison to a coverglass (Glass) in two different culture conditions: with (osteogenic medium (OM)) and without (proliferative medium (PM)) osteogenic factors. To evaluate cell adhesion, hBMSCs phosphorylated focal adhesion kinase (pFAK) foci were analyzed by confocal laser scanning microscopy (CLSM) at 24 h: the TiO₂ surface showed a higher number of pFAK foci with respect to Glass. The hBMSCs differentiation to osteoblasts was evaluated in both PM and OM culture conditions by enzyme-linked immunosorbent assay (ELISA), CLSM and real-time quantitative reverse transcription PCR (qRT-PCR) at 28 days. In comparison with Glass, TiO₂ surface in combination with OM conditions increased the content of extracellular bone proteins, calcium deposition and alkaline phosphatase activity. The qRT-PCR analysis revealed, both in PM and OM, that TiO₂ surface increased at seven and 28 days the expression of osteogenic genes. All together, these results demonstrate the capability of TiO₂ nanostructured surface to promote hBMSCs osteoblast differentiation and its potentiality in biomedical applications.

Adult Stem Cells and Skeletal Muscle Regeneration

Satellite cells are unipotent stem cells involved in muscle regeneration. However, the skeletal muscle microenvironment exerts a dominant influence over stem cell function. The cell intrinsic complexity of the skeletal muscle niche located within the connective tissue between fibers includes motor neurons, tendons, blood vessels, immune response mediators and interstitial cells. All these cell types modulate the trafficking of stimuli responsible of muscle fiber regeneration. In addition, several stem cell types have been discovered in skeletal muscle tissue, mainly located in the interstitium. The majority of these stem cells appears to directly contribute to myogenic differentiation, although some of them are mainly implicated in paracrine effects. This review focuses on adult stem cells, which have been used for therapeutic purposes, mainly in animal models of chronic muscle degeneration. Emerging literature identifies other myogenic progenitors generated from pluripotent stem cells as potential candidates for the treatment of skeletal muscle degeneration. However, adult stem cells still represent the gold standard for future comparative studies.

Osteogenic Potential of Human Oral-Periosteal Cells (PCs) Isolated From Different Oral Origin: An In Vitro Study

The periosteum is a specialized connective tissue containing multipotent stem cells capable of bone formation. In this study, we aimed at demonstrating that human oral periosteal cells derived from three different oral sites (upper vestibule, lower vestibule, and hard palate) represent an innovative cell source for maxillo-facial tissue engineering applications in terms of accessibility and self-commitment towards osteogenic lineage. Periosteal cells (PCs) were isolated from patients with different ages (20-30 yy, 40-50 yy, 50-60 yy); we then analyzed the in vitro proliferation capacity and the bone self-commitment of cell clones culturing them without any osteogenic supplement to support their differentiation. We found that oral PCs, independently of their origin and age of patients, are mesenchymal stem cells with stem cell characteristics (clonogenical and proliferative activity) and that, even in absence of any osteogenic induction, they undertake the osteoblast lineage after 45 days of culture. These results suggest that oral periosteal cells could replace mesenchymal cells from bone marrow in oral tissue-engineering applications.

Tissue Characterization after a New Disaggregation Method for Skin Micro-Grafts Generation

Several new methods have been developed in the field of biotechnology to obtain autologous cellular suspensions during surgery, in order to provide one step treatments for acute and chronic skin lesions. Moreover, the management of chronic but also acute wounds resulting from trauma, diabetes, infections and other causes, remains challenging. In this study we describe a new method to create autologous micro-grafts from cutaneous tissue of a single patient and their clinical application. Moreover, in vitro biological characterization of cutaneous tissue derived from skin, de-epidermized dermis (Ded) and dermis of multi-organ and/or multi-tissue donors was also performed. All tissues were disaggregated by this new protocol, allowing us to obtain viable micro-grafts. In particular, we reported that this innovative protocol is able to create bio-complexes composed by autologous micro-grafts and collagen sponges ready to be applied on skin lesions. The clinical application of autologous bio-complexes on a leg lesion was also reported, showing an improvement of both re-epitalization process and softness of the lesion. Additionally, our in vitro model showed that cell viability after mechanical disaggregation with this system is maintained over time for up to seven (7) days of culture. We also observed, by flow cytometry analysis, that the pool of cells obtained from disaggregation is composed of several cell types, including mesenchymal stem cells, that exert a key role in the processes of tissue regeneration and repair, for their high regenerative potential. Finally, we demonstrated in vitro that this procedure maintains the sterility of micro-grafts when cultured in Agar dishes. In summary, we conclude that this new regenerative approach can be a promising tool for clinicians to obtain in one step viable, sterile and ready to use micro-grafts that can be applied alone or in combination with most common biological scaffolds.

Predictors of outcome in ICU patients with septic shock caused by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae

The aim of this study was to identify factors associated with mortality in intensive care unit patients with Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) septic shock. A retrospective analysis of intensive care unit patients with KPC-Kp infection and septic shock observed in a large teaching hospital from November 2010 to December 2014 was performed. A total of 111 patients were included in the study. The most frequent source of infection was unknown-focus bacteraemia in 53 patients (47.7%). The rate of resistance to colistin was 51.3%; 30-day mortality was reported for 44 patients (39.6%). Surviving patients were more frequently treated with an initial therapy (within 24 hours) including two or more antibiotics displaying in vitro activity against the isolated KPC-Kp strain (41.8 vs. 18.1%, p 0.01) and were also more likely to receive a definitive therapy including two or more in vitro active antibiotics (85.1 vs. 15.9%, p <0.001). Cox regression analysis revealed that a colistin-containing antibiotic regimen (hazard ratio (HR) 0.21, confidence interval (CI) 95% 0.05-0.72, p <0.001), use of two or more in vitro active antibiotics as definite therapy (HR 0.08, CI 95% 0.02-0.21, p <0.001) and control of removable source of infection (HR 0.14, CI 95% 0.04-0.25, p <0.001) were associated with favourable outcome; colistin resistance (HR 8.09, CI 95% 3.14-11.23, p 0.001) and intra-abdominal source of infection (HR 2.92, CI 95% 2.11-4.12, p 0.002) were associated with death. In conclusion, use of a definitive therapy with at least two antibiotics displaying in vitro activity against the KPC-Kp isolates was the most important determinant of favourable outcome, whilst isolation of colistin-resistant strains was associated with death in septic patients with KPC-Kp infection.

Renal cavernous hemangioma: robot-assisted partial nephrectomy with selective warm ischemia. Case report and review of the literature

Renal hemangioma is a relatively rare benign tumor with a wide range of clinical and radiological presentation, not easy to differentiate preoperatively from a renal cancer. Due to its benign nature complete surgical resection is the recommended therapy and is considered curative. A 73-year old male patient followed-up for a lung carcinoma and a chronic renal failure underwent a CT scan showing a 35-mm mass of the inferior pole of the left kidney. The patient underwent robot-assisted partial nephrectomy with left inferior pole selective warm ischemia. The outcome was favorable and no repercussions on the renal reserve were observed postoperatively. Histopathological characteristics of the surgical specimen were consistent with renal cavernous hemangioma. A robot-assisted operation allows the fine dissection required to carry out a bloodless nephron-sparing surgery without a complete warm ischemia. The use of robot could be noteworthy for nephron-sparing surgery in cases of concomitant chronic renal failure.

Mesodermal iPSC-derived progenitor cells functionally regenerate cardiac and skeletal muscle

Conditions such as muscular dystrophies (MDs) that affect both cardiac and skeletal muscles would benefit from therapeutic strategies that enable regeneration of both of these striated muscle types. Protocols have been developed to promote induced pluripotent stem cells (iPSCs) to differentiate toward cardiac or skeletal muscle; however, there are currently no strategies to simultaneously target both muscle types. Tissues exhibit specific epigenetic alterations; therefore, source-related lineage biases have the potential to improve iPSC-driven multilineage differentiation. Here, we determined that differential myogenic propensity influences the commitment of isogenic iPSCs and a specifically isolated pool of mesodermal iPSC-derived progenitors (MiPs) toward the striated muscle lineages. Differential myogenic propensity did not influence pluripotency, but did selectively enhance chimerism of MiP-derived tissue in both fetal and adult skeletal muscle. When injected into dystrophic mice, MiPs engrafted and repaired both skeletal and cardiac muscle, reducing functional defects. Similarly, engraftment into dystrophic mice of canine MiPs from dystrophic dogs that had undergone TALEN-mediated correction of the MD-associated mutation also resulted in functional striatal muscle regeneration. Moreover, human MiPs exhibited the same capacity for the dual differentiation observed in murine and canine MiPs. The findings of this study suggest that MiPs should be further explored for combined therapy of cardiac and skeletal muscles.

Molecular signature of amniotic fluid derived stem cells in the fetal sheep model of myelomeningocele

Abnormal cord development results in spinal cord damage responsible for myelomeningocele (MMC). Amniotic fluid-derived stem cells (AFSCs) have emerged as a potential candidate for applications in regenerative medicine. However, their differentiation potential is largely unknown as well as the molecular signaling orchestrating the accurate spinal cord development. Fetal lambs underwent surgical creation of neural tube defect and its subsequent repair. AFSCs were isolated, cultured and characterized at the 12th (induction of MMC), 16th (repair of malformation), and 20th week of gestation (delivery). After performing open hysterectomy, AF collections on fetuses with sham procedures at the same time points as the MMC creation group have been used as controls. Cytological analyses with the colony forming unit assay, XTT and alkaline-phosphatase staining, qRT-PCR gene expression analyses (normalized with aged match controls) and NMR metabolomics profiling were performed. Here we show for the first time the metabolomics and molecular signature variation in AFSCs isolated in the sheep model of MMC, which may be used as diagnostic tools for the in utero identification of the neural tube damage. Intriguingly, PAX3 gene involved in the murine model for spina bifida is modulated in AFSCs reaching the peak of expression at 16 weeks of gestation, 4 weeks after the intervention. Our data strongly suggest that AFSCs reorganize their differentiation commitment in order to generate PAX3-expressing progenitors to counteract the MMC induced in the sheep model. The gene expression signature of AFSCs highlights the plasticity of these cells reflecting possible alterations of embryonic development.

Investigation of low-level laser therapy potentiality on proliferation and differentiation of human osteoblast-like cells in the absence/presence of osteogenic factors

Several studies have shown that low-level laser irradiation (LLLI) has beneficial effects on bone regeneration. The objective of this study was to examine the in vitro effects of LLLI on proliferation and differentiation of a human osteoblast-like cell line (Saos-2 cell line). Cultured cells were exposed to different doses of LLLI with a semiconductor diode laser (659 nm; 10 mW power output). The effects of laser on proliferation were assessed daily up to seven days of culture in cells irradiated once or for three consecutive days with laser doses of 1 or 3 J/cm(2). The obtained results showed that laser stimulation enhances the proliferation potential of Saos-2 cells without changing their telomerase pattern or morphological characteristics. The effects on cell differentiation were assessed after three consecutive laser irradiation treatments in the presence or absence of osteo-inductive factors on day 14. Enhanced secretion of proteins specific for differentiation toward bone as well as calcium deposition and alkaline phosphatase activity were observed in irradiated cells cultured in a medium not supplemented with osteogenic factors. Taken together these findings indicate that laser treatment enhances the in vitro proliferation of Saos-2 cells, and also influences their osteogenic maturation, which suggest it is a helpful application for bone tissue regeneration.

Kidney disease in HIV-infected patients

The introduction of highly active antiretroviral therapy (HAART) has reduced mortality and improved life expectancy of HIV-positive patients. However, increased survival is associated with increased prevalence of comorbidities, such as cardiovascular disease, hepatic and renal disease. Kidney disease, including HIV-associated nephropathy, acute renal failure and chronic kidney disease, represents one of the main causes of morbidity and mortality, especially if associated to other risk factors, i.e. hypertension, diabetes, older age, black race and hepatitis C coinfection. Careful evaluation of renal function may help identifying kidney disease in its early stages. In addition, proper management of hypertension and diabetes is recommended. Even if HAART has changed the natural course of HIV-associated nephropathy, reducing the risk of End-stage Renal Disease (ERDS), some antiretroviral regimens have been related with the development of acute or chronic kidney disease. Further studies are needed to optimize the management of renal disease among HIV-infected patients.

A comparative analysis of the in vitro effects of pulsed electromagnetic field treatment on osteogenic differentiation of two different mesenchymal cell lineages

Human mesenchymal stem cells (MSCs) are a promising candidate cell type for regenerative medicine and tissue engineering applications. Exposure of MSCs to physical stimuli favors early and rapid activation of the tissue repair process. In this study we investigated the in vitro effects of pulsed electromagnetic field (PEMF) treatment on the proliferation and osteogenic differentiation of bone marrow MSCs (BM-MSCs) and adipose-tissue MSCs (ASCs), to assess if both types of MSCs could be indifferently used in combination with PEMF exposure for bone tissue healing. We compared the cell viability, cell matrix distribution, and calcified matrix production in unstimulated and PEMF-stimulated (magnetic field: 2 mT, amplitude: 5 mV) mesenchymal cell lineages. After PEMF exposure, in comparison with ASCs, BM-MSCs showed an increase in cell proliferation (p<0.05) and an enhanced deposition of extracellular matrix components such as decorin, fibronectin, osteocalcin, osteonectin, osteopontin, and type-I and -III collagens (p<0.05). Calcium deposition was 1.5-fold greater in BM-MSC-derived osteoblasts (p<0.05). The immunofluorescence related to the deposition of bone matrix proteins and calcium showed their colocalization to the cell-rich areas for both types of MSC-derived osteoblast. Alkaline phosphatase activity increased nearly 2-fold (p<0.001) and its protein content was 1.2-fold higher in osteoblasts derived from BM-MSCs. The quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis revealed up-regulated transcription specific for bone sialoprotein, osteopontin, osteonectin, and Runx2, but at a higher level for cells differentiated from BM-MSCs. All together these results suggest that PEMF promotion of bone extracellular matrix deposition is more efficient in osteoblasts differentiated from BM-MSCs.

In vitro osteogenesis of human stem cells by using a three-dimensional perfusion bioreactor culture system: a review

Tissue engineering (by culturing cells on appropriate scaffolds, and using bioreactors to drive the correct bone structure formation) is an attractive alternative to bone grafting or implantation of bone substitutes. Osteogenesis is a biological process that involves many molecular intracellular pathways organized to optimize bone modeling. The use of bioreactor systems and especially the perfusion bioreactor, provides both the technological means to reveal fundamental mechanisms of cell function in a 3D environment, and the potential to improve the quality of engineered tissues. In this mini-review all the characteristics for the production of an appropriate bone construct are analyzed: the stem cell source, scaffolds useful for the seeding of pre-osteoblastic cells and the effects of fluid flow on differentiation and proliferation of bone precursor cells. By automating and standardizing tissue manufacture in controlled closed systems, engineered tissues may reduce the gap between the process of bone formation in vitro and subsequent graft of bone substitutes in vivo.

Candidemia in Neurosurgical Intensive Care Unit: preliminary analysis of the effect of topical Nystatin prophylaxis and adequate source control on patients with early tracheostomy intubation

INTRODUCTION

The present study represents a preliminary evaluation of the impact of topical nystatin prophylaxis administration and adequate CVC management on reducing the chance of developing candidemia in neurosurgical intensive care unit (NICU) patients.

MATERIALS AND METHODS

We conducted a case-control study at the nine bed NICU of the Policlinico "Umberto I" teaching hospital in Rome, Italy, during the period from January 2011 to July 2012. We compared eight patients with culture proven Candida bloodstream infection (CBSI) with a control group of 19 patients who did not have evidence of CBSI.

RESULTS

When the CBSI group was compared with the control group, the former were more likely than controls to not have received nystatin prophylaxis and adequate catheter care (p= 0,008). When CBSI group was matched with patients with no adequate source control and nystatin prophylaxis, average NICU stay (71.13 days vs 19.0 days) was significant (mean difference = -52.12 days, 95% CI -97.11 to -7.14, p= 0.028). The same was true for mean time of glucocorticoid exposure (mean difference = -10.5 days, 95% CI -17.35 to -3.65, p<0.01). Binary logistic regression analysis demonstrated no significant association between topical nystatin prophylaxis (p= 0.99), length of NICU stay (p= 0.99), time of glucocorticoid exposure (p= 0.99) and candidemia.

CONCLUSION

Topical prophylaxis with nystatin and adequate source control proved to be effective in preventing invasive candidiasis in patients admitted to the NICU.

Vitamin D deficiency in HIV infection: an underestimated and undertreated epidemic

Hypovitaminosis D is a very common disorder, regarding both Western and developing countries. A growing amount of data over the last years have shown vitamin D deficiency to be high prevalent among HIV-positive subjects. In addition to "classic" risk factors, such as female sex, low dietary intake, dark skin pigmentation and low sun exposure, HIV-related factors, including immune activation and antiretroviral adverse effects, may affect vitamin D status. Even if both protease inhibitors and non-nucleoside reverse transcriptase inhibitors have been associated with low vitamin D levels, available evidences have failed to univocally associate hypovitaminosis D with specific antiretroviral class effects. Low vitamin D is known to have a negative impact not only on bone health, but also on neurocognitive, metabolic, cardiovascular and immune functions. Similarly to the general population, several studies conducted on HIV-infected subjects have associated hypovitaminosis D with a greater risk of developing osteopenia/osteoporosis and fragility fractures. Analogously, vitamin D deficiency has been described as an independent risk factor for cardiovascular disease and metabolic disorders, such as insulin resistance and type 2 diabetes mellitus. Last EACS guidelines suggest to screen for hypovitaminosis D every HIV-positive subject having a history of bone disease, chronic kidney disease or other known risk factors for vitamin D deficiency. Vitamin D repletion is recommended when 25-hydroxyvitamin D levels are below 10 ng/ml. Furthermore, it may be indicated in presence of 25OHD values between 10 and 30 ng/ml, if associated with osteoporosis, osteomalacia or increased parathyroid hormone levels. The optimal repletion and maintenance dosing regimens remain to be established, as well as the impact of vitamin D supplementation in preventing comorbidities.

[The psycho-physical fitness of the railways workers]

The world of psycho-physical fitness of the workers in the railways has an important basis on a complex system of national and European laws. Different laws pursue different purposes: Occupational Safety and Health (with a focus on the worker), Transport Safety (which preserve the safety of the community, acting on the human factors) and Road Transport Safety. Many of the Italian National laws already are or are about to become the implementation of European Directives and Recommendations. In addition, on the European and National laws, a big number of documents concerning this specific topic, comes from public Institutes or international associations for railways standardization and has a great impact on the criteria for the medical fitness judgments.

Low-amplitude high frequency vibration down-regulates myostatin and atrogin-1 expression, two components of the atrophy pathway in muscle cells

Whole body vibration (WBV) is a very widespread mechanical stimulus used in physical therapy, rehabilitation and fitness centres. It has been demonstrated that vibration induces improvements in muscular strength and performance and increases bone density. We investigated the effects of low-amplitude, high frequency vibration (HFV) at the cellular and tissue levels in muscle. We developed a system to produce vibrations adapted to test several parameters in vitro and in vivo. For in vivo experiments, we used newborn CD1 wild-type mice, for in vitro experiments, we isolated satellite cells from 6-day-old CD1 mice, while for proliferation studies, we used murine cell lines. Animals and cells were treated with high frequency vibration at 30 Hz. We analyzed the effects of mechanical stimulation on muscle hypertrophy/atrophy pathways, fusion enhancement of myoblast cells and modifications in the proliferation rate of cells. Results demonstrated that mechanical vibration strongly down-regulates atrophy genes both in vivo and in vitro. The in vitro experiments indicated that mechanical stimulation promotes fusion of satellite cells treated directly in culture compared to controls. Finally, proliferation experiments indicated that stimulated cells had a decreased growth rate compared to controls. We concluded that vibration treatment at 30 Hz is effective in suppressing the atrophy pathway both in vivo and in vitro and enhances fusion of satellite muscle cells.

Adherence and genotypic drug resistance mutations in HIV-1-infected patients failing current antiretroviral therapy

The aim of this study was to assess the correlation between the estimated adherence of HIV-1 infected patients with antiretroviral (ARV) therapy failure and drug-resistant mutations. We studied 40 patients with virological and immunological ARV-therapy failure. In order to assess the adherence of patients we used the SERAD questionnaire. Genomic sequencing of the HIV-1 pol gene was performed. 100% adherence was reported by 27 patients (67.5%) (adherent patients). Multivariate analysis showed that only baseline and nadir CD4+ counts maintained a significant correlation with the adherence. For PR and NNRTI mutations, we did not find any difference between the two groups of patients. Baseline NRTI mutations were higher in adherent patients than in non-adherent patients (p<0.05). No differences were found between plasma mutations and PBMC mutations. The authors conclude that genotypic resistance mutations were found in the majority of patients with ARV-therapy failure despite a good self-reported adherence to therapy. Adequate adherence to therapy is not the only key factor in viral suppression.

The differentiation of human adipose-derived stem cells (hASCs) into osteoblasts is promoted by low amplitude, high frequency vibration treatment

Several studies have demonstrated that tissue culture conditions influence the differentiation of human adipose-derived stem cells (hASCs). Recently, studies performed on SAOS-2 and bone marrow stromal cells (BMSCs) have shown the effectiveness of high frequency vibration treatment on cell differentiation to osteoblasts. The aim of this study was to evaluate the effects of low amplitude, high frequency vibrations on the differentiation of hASCs toward bone tissue. In view of this goal, hASCs were cultured in proliferative or osteogenic media and stimulated daily at 30Hz for 45min for 28days. The state of calcification of the extracellular matrix was determined using the alizarin assay, while the expression of extracellular matrix and associated mRNA was determined by ELISA assays and quantitative RT-PCR (qRT-PCR). The results showed the osteogenic effect of high frequency vibration treatment in the early stages of hASC differentiation (after 14 and 21days). On the contrary, no additional significant differences were observed after 28days cell culture. Transmission Electron Microscopy (TEM) images performed on 21day samples showed evidence of structured collagen fibers in the treated samples. All together, these results demonstrate the effectiveness of high frequency vibration treatment on hASC differentiation toward osteoblasts.