Manlio Barbarisi

FROM CELL-ECM INTERACTIONS TO TISSUE ENGINEERING

The extracellular matrix (ECM) consists of a complex mixture of structural and functional macromolecules and serves an important role in tissue and organ morphogenesis and in the maintenance of cell and tissue structure and function. The great diversity observed in the morphology and composition of the ECM contributes enormously to the properties and function of each organ and tissue. The ECM is also important during growth, development, and wound repair: its own dynamic composition acts as a reservoir for soluble signaling molecules and mediates signals from other sources to migrating, proliferating, and differentiating cells. Approaches to tissue engineering center on the need to provide signals to cell populations to promote cell proliferation and differentiation. These “external signals” are generated from growth factors, cell–ECM, and cell–cell interactions, as well as from physical‐chemical and mechanical stimuli. This review considers recent advances in knowledge about cell–ECM interactions. A description of the main ECM molecules and cellular receptors with particular care to integrins and their role in stimulation of specific types of signal transduction pathways is also explained. The general principles of biomaterial design for tissue engineering are considered, with same examples. J. Cell. Physiol. 199: 174–180, 2004© 2003 Wiley‐Liss, Inc.

Smart materials as scaffolds for tissue engineering

In this review, we focused our attention on the more important natural extracellular matrix (ECM) molecules (collagen and fibrin), employed as cellular scaffolds for tissue engineering and on a class of semi‐synthetic materials made from the fusion of specific oligopeptide sequences, showing biological activities, with synthetic materials. In particular, these new “intelligent” scaffolds may contain oligopeptide cleaving sequences specific for matrix metalloproteinases (MMPs), integrin binding domains, growth factors, anti‐thrombin sequences, plasmin degradation sites, and morphogenetic proteins. The aim was to confer to these new “intelligent” semi‐synthetic biomaterials, the advantages offered by both the synthetic materials (processability, mechanical strength) and by the natural materials (specific cell recognition, cellular invasion, and the ability to supply differentiation/proliferation signals). Due to their characteristics, these semi‐synthetic biomaterials represent a new and versatile class of biomimetic hybrid materials that hold clinical promise in serving as implants to promote wound healing and tissue regeneration.

A critical overview of ESEM applications in the biological field

Scanning Electron Microscope (SEM) is a powerful research tool, but since it requires high vacuum conditions, the wet materials and biological samples must undergo a complex preparation that limits the application of SEM on this kind of specimen and often causes the introduction of artifacts. The introduction of Environmental Scanning Electron Microscope (ESEM), working in gaseous atmosphere, represented a new perspective in biological research. Despite the fact that many biological applications have demonstrated the convenience of ESEM, the full potentialities of this technology are still under investigation. In this review, the exploration of the recent literature data confronted with the first results obtained in our experimental work suggest that ESEM represents an important extension of conventional scanning microscopy.

Neurobiology of pain

The neurobiology of pain had a notable interest in research focused on the study of neuronal plasticity development, nociceptors, molecular identity, signaling mechanism, ionic channels involved in the generation, modulation and propagation of action potential in all type of excitable cells. All the findings open the possibility for developing new therapeutic treatment. Nociceptive/inflammatory pain and neuropathic pain represent two different kinds of persistent chronic pain. We have reviewed the different mechanism suggested for the maintenance of pain, like descending nociceptive mechanism and their changes after tissue damage, including suppression and facilitation of defence behavior during pain. The role of these changes in inducing NMDA and AMPA receptors gene expression, after prolonged inflammation is emphasized by several authors. Furthermore, a relation between a persistent pain and amygdale has been shown. Molecular biology is the new frontier in the study of neurobiology of pain. Since the entire genome has been studied, we will able to find new genes involved in specific condition such as pain, because an altered gene expression can regulate neuronal activity after inflammation or tissue damage. J. Cell. Physiol. 209: 8–12, 2006.

Therapy with autologous adipose-derived regenerative cells for the care of chronic ulcer of lower limbs in patients with peripheral arterial disease.

BACKGROUND An ulcer is a trophic lesion with loss of tissue that often has a multifactorial genesis. It typically diverges from the physiologic processes of regeneration because it rarely tends to heal spontaneously. In this study, we used purified adipose-derived stem and regenerative cells (ADRCs) extracted from autologous fat, for the care of chronic ulcers of the lower limbs of arteriopathic patients. The primary objective of this study was complete re-epithelization of chronic ulcers; the secondary objective was a decrease in diameter and depth. METHODS From January 2010 to January 2012, 20 patients with peripheral arterial disease, with an ankle-brachial index between 0.30-0.40, in the age range 60-70 y (14 men and six women), with chronic ulcers of the lower limb, were involved in the study. Only 10 arteriopathic patients (seven men and three women) with chronic ulcers of the lower limb were surgically treated. Using the Celution system, we isolated a solution of ADRCs in about 150 min. The isolated cells were injected through a 10-mL syringe into the edges of the ulcer, taking care to spread it in all directions. Using a small amount of Celution extract, we performed cell characterization by flow cytometry analysis and cell viability assay. RESULTS We monitored patients treated with ADRC or untreated at 4, 10, 20, 60, and 90 d. In all cases treated with ADRC, we found a reduction in both diameter and depth of the ulcer, which led to a decrease in pain associated with the ulcer process. In six of 10 cases there was complete healing of the ulcer. Characterization of the cells by FACS clearly showed that the ADRC cells contained adipose-derived stem cells. Viability assays demonstrated that partial or total closure of the ulcer was attributable exclusively to ADRC cells present in the Celution extract, and not to growth factors extracted during the process of purification of the Celution and injected together with the cells. CONCLUSIONS For the first time, the Celution method has been applied for the care of chronic ulcers in the lower extremity of patients with peripheral arterial disease. Our results demonstrate that the technique is feasible for autologous cell application and is not associated with adverse events. Moreover, the transplantation of autologous stem cells extracted with Celution may represent a valuable method for the treatment of chronic ulcers in lower limbs of arteriopathic patients.

Ionic channels and neuropathic pain: Phisiopatology and applications

Neuropathic pain is defined by the International Association for Pain research as a pain associated to a primary lesion or a dysfunction of the central or peripheral system. Over the past few years the causes of the neuropathic pain were not known and there were not good treatments for it, now we have a better knowledge of the physiopathological aspects and there is a wider diffusion of the research for target aimed therapies. The physiologic genesis of nervous messages occurs exclusively in skin sensorial endings or in nerve tissues as a consequence of an adequate sensorial stimulus and depends on the quick variations of the electric potential difference at the endings of ionic membranes. These variations of even 500 V a second are possible because of the presence of ionic channels. In neuropathic pain impulses can be originated even from ectopic sites. Ectopic discharges originated in a peripheral neuropathic system have an important role in the early stage of neuropathic pain development in two different ways. First they give an excess of spontaneous and evoked electric impulses to the central nervous system, causing a primitive neuropathic pain signal; then the ectopic activity develops and maintains the central sensitisation process. All this amplifies the afferent signals deriving from residual efferents that go on innerving cutaneous areas damaged and partly disnerved, causing tactile allodynie. Sodium channels are the greatest responsible for electrogenesis, that is the basis of the action potential generation and its propagation. Action potential begins after a depolarization such that it could cause a membrane transitory modification, turning prevalently permeable to Na+ more than to K+ as during a release phase. Neuropathy generates a local accumulation of sodium channels, with a consequent increase of density. This remodel seems to be the basis of neuro hyperexecitably. Calcium channels have also an important role in cell working. Intracellular calcium increase contributes to depolarization processes, through kinase and determines the phosphorylation of membrane proteins that can make powerful the efficacy of the channels themselves. In the future new diagnostic opportunities of physiopathologist mechanism leading to neuropathic pain will allow treatments aimed at specific molecular changes of ionic channels. J. Cell. Physiol. 215: 8–14, 2008.

Buprenorphine in long-term control of chronic pain in cancer patients.

The aim of this randomized open-label prospective study was to evaluate the analgesic activity of buprenorphine in a transdermal formulation for cancer chronic pain control versus sustained-release morphine, in all cases combined with oral tramadol. A transdermal system with 35 microg/h buprenorphine was applied to the first group of patients (BT); the second group received 60 mg/day of sustained-release morphine (MT). In both groups oral tramadol was administered to a maximum of 200 mg daily, in case of need. The administration of transdermal buprenorphine versus morphine resulted in significant differences in the physical pain (P = 0.01), mental health (P = 0.03) and vitality (P = 0.001). These data indicated that the BT group showed an improvement of pain and a positive effect on the quality life.

Growth and endothelial differentiation of adipose stem cells on polycaprolactone

Adipose tissue is a readily available source of multipotent adult stem cells for use in tissue engineering/regenerative medicine. Various growth factors have been used to stimulate acquisition of endothelial characteristics by adipose-derived stem cells (ADSC). Herein, we study the growth and endothelial differentiation potential of ADSC seeded onto a porous polycaprolactone (PCL) scaffold. The objective of this study is to demonstrate that PCL is a good material to be used as a scaffold to support reconstruction of new endothelial tissue using adipose stem cells. We found that undifferentiated ADSC adhere and grow on PCL. We show that, after culture in endothelial differentiation medium, ADSC were positive to LDL uptake and expressed molecular markers characteristic of endothelial cells (CD31; eNOS and vWF). In addition, our study defines the time required for the differentiation of ADSC directly onto PCL. This study suggests that PCL can be used as a scaffold to generate endothelial tissue in vitro. PLC has excellent mechanical properties and a slow degradation rate. Moreover, based on our results, we propose that PCL could be used to graft scaffolds coated with endothelial cells derived from ADSC stem cells. Endothelial cells-coated PCL could find several applications to replace damaged area of the body; for example, a possible use could be the generation of vascular grafts.

Pregabalin and transcutaneous electrical nerve stimulation for postherpetic neuralgia treatment.

ObjectivePostherpetic neuralgia (PHN) is responsible for one of the most common types of neuropathic pain, described as a burning pain that shakes, hits, and tightens and includes allodynia and paresthesia. Aim of the StudyTo evaluate the efficacy of Pregabalin when used during transcutaneous electric nerve stimulation (TENS) in patients with PHN and to analyze any changes in physical activity and sleep quality. MethodsPatients aged 50 to 80 years were included in this randomized study. We enrolled 15 male (average age 65±8.6 y) and 15 female patients (average age 64±8.2 y). The male patients had a history of neuropathic pain lasting 15.6±8.8 months whereas the female patients had a history of neuropathic pain lasting about 14.9±8.6 months. We began with 1 week of patient screening followed by a week of Pregabalin titration. Then, we established the dose of Pregabalin for each patient to obtain visual analog scale (VAS) of less than 60 mm. The eligible patients were randomly divided into 2 groups receiving Pregabalin + TENS or Pregabalin+TENS placebo for the following 4 weeks. Patients underwent 8 outpatient visits during which they completed VAS, SF-McGill Pain Questionnaire, and sleep interference questionnaire. ResultsThe resulting data showed that Pregabalin administration associated with TENS reduced pain in patients with PHN. At the end of the treatment, all the observed groups presented a reduction of mean VAS. The group treated with Pregabalin 300 (P300)+TENS had a reduction of pain of 30% and the group treated with Pregabalin 600 (P600)+TENS had a reduction of pain of 40%. The comparison between group P300+TENS versus group P300+TENS placebo showed a statistically significant reduction of VAS (P300+TENS 25±0.67 vs. P300+TENS placebo 39±1.19 P<0.02). Moreover, the comparison between group P600+TENS versus group P600+TENS placebo has shown a statistically significant reduction of VAS (P600+TENS 23±0.78 vs. P600+TENS placebo 32±0.81 P<0.02). At the end of the study, all groups showed a statistically significant difference in terms of sleep interference, Short-Form McGill Pain Questionnaire total score, and Short-Form McGill Pain Questionnaire Present Pain Intensity. ConclusionsThese data support the conclusion that Pregabalin gives better results when combined with TENS therapy, which is an analgesic nonpharmacologic procedure. Therefore, a multidisciplinary treatment should be considered for this kind of pain.

Opioids Switching with Transdermal Systems in Chronic Cancer Pain

BackgroundDue to tolerance development and adverse side effects, chronic pain patients frequently need to be switched to alternative opioid therapyObjectiveTo assess the efficacy and tolerability of an alternative transdermally applied (TDS) opioid in patients with chronic cancer pain receiving insufficient analgesia using their present treatment.MethodsA total of 32 patients received alternative opioid therapy, 16 were switched from buprenorphine to fentanyl and 16 were switched from fentanyl to buprenorphine. The dosage used was 50% of that indicated in equipotency conversion tables. Pain relief was assessed at weekly intervals for the next 3 weeksResultsPain relief as assessed by VAS, PPI, and PRI significantly improved (p < 0.0001) in all patients at all 3 follow up visits. After 3 weeks of treatment, the reduction in the mean VAS, PPI, and PRI scores in the fentanyl and buprenorphine groups was 68, 77, 74, and 69, 79, and 62%, respectively. Over the same time period the use of oral morphine as rescue medication was reduced from 27.5 ± 20.5 (mean ± SD) to 3.75 ± 8.06, and 33.8 ± 18.9 to 3.75 ± 10.9 mg/day in the fentanyl and buprenorphine groups, respectively. There was no significant difference in either pain relief or rescue medication use between the two patient groups The number of patient with adverse events fell during the study. After the third week of the treatment the number of patients with constipation was reduced from 11 to 5, and 10 to 4 patients in the fentanyl and buprenorphine groups, respectively. There was a similar reduction in the incidence of nausea and vomiting. No sedation was seen in any patient after one week of treatment.ConclusionOpioid switching at 50% of the calculated equianalgesic dose produced a significant reduction in pain levels and rescue medication. The incidence of side effects decreased and no new side effects were noted. Further studies are required to provide individualized treatment for patients according to their different types of cancer.