Giandomenico Logroscino

Carbonated hydroxyapatite as bone substitute

Abstract B-carbonateapatite (CHA) powder was synthesized starting from calcium nitrate tetrahydrate, diammonium hydrogen phosphate and sodium hydrogen carbonate. The powder was fully characterized in terms of phase purity, stoichiometry, morphology, specific surface area and particle size distribution. The thermal stability of the powder in air and CO 2 atmosphere also was evaluated by thermal analysis. Electroacoustic analysis of the water based suspension of the CHA powder was used to determine the stability of the slurry. Porous bodies of CHA were prepared by impregnation of cellulose sponges with a proper slurry of the powder and optimizing the subsequent sintering. The fired samples were characterized in terms of phase purity and carbonate content, microstructure and pore size distribution. The compressive strength also was evaluated, resulting in 6.0±0.5 MPa. First results of in vivo tests on New Zealand White rabbits showed good biocompatibility and osteointegration of the CHA implant, with higher osteoconductive properties and earlier bioresorption, compared to HA samples, used as control.

Bone substitutes in orthopaedic surgery: from basic science to clinical practice

Bone substitutes are being increasingly used in surgery as over two millions bone grafting procedures are performed worldwide per year. Autografts still represent the gold standard for bone substitution, though the morbidity and the inherent limited availability are the main limitations. Allografts, i.e. banked bone, are osteoconductive and weakly osteoinductive, though there are still concerns about the residual infective risks, costs and donor availability issues. As an alternative, xenograft substitutes are cheap, but their use provided contrasting results, so far. Ceramic-based synthetic bone substitutes are alternatively based on hydroxyapatite (HA) and tricalcium phosphates, and are widely used in the clinical practice. Indeed, despite being completely resorbable and weaker than cortical bone, they have exhaustively proved to be effective. Biomimetic HAs are the evolution of traditional HA and contains ions (carbonates, Si, Sr, Fl, Mg) that mimic natural HA (biomimetic HA). Injectable cements represent another evolution, enabling mininvasive techniques. Bone morphogenetic proteins (namely BMP2 and 7) are the only bone inducing growth factors approved for human use in spine surgery and for the treatment of tibial nonunion. Demineralized bone matrix and platelet rich plasma did not prove to be effective and their use as bone substitutes remains controversial. Experimental cell-based approaches are considered the best suitable emerging strategies in several regenerative medicine application, including bone regeneration. In some cases, cells have been used as bioactive vehicles delivering osteoinductive genes locally to achieve bone regeneration. In particular, mesenchymal stem cells have been widely exploited for this purpose, being multipotent cells capable of efficient osteogenic potential. Here we intend to review and update the alternative available techniques used for bone fusion, along with some hints on the advancements achieved through the experimental research in this field.

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.

Effect of pre-operative physiotherapy in patients with end-stage osteoarthritis undergoing hip arthroplasty

Objective: To examine the effect of pre-operative physiotherapy before hip arthroplasty in patients with end-stage hip osteoarthritis. Design: A prospective randomized controlled study. Setting: Physical medicine and rehabilitation and orthopaedic departments of Policlinico Gemelli of Rome. Subjects: Twenty-three patients randomized in study and control groups. Intervention: The study group took part in an educational and physiotherapy programme one month before surgery. Both groups took part in the same inpatient rehabilitation programme after surgery. Main outcome measures: Both groups were evaluated one month (T0) and the day before arthroplasty (T1), after 15 days (T2), four weeks (T3) and three months (T4) post surgery, using the Barthel Index, the Short Form-36 (SF-36), the Western Ontario and McMaster Osteoarthritis Index (WOMAC), the Hip Harris Score (HHS), visual analogue scale (VAS), the British Medical Research Council (BMRC) measures of hip abductor and quadriceps strength and range of hip abduction and external rotation. Results: There were no significant differences between groups with regard to the Barthel Index, SF-36, WOMAC and HHS at T4. The study group presented significant improvements of the SF-36 physical composite score at T1. The hip external rotation was significantly higher in the study group at each evaluation and the visual analogue scale values were lower at T1, T3 and T4. Conclusion: Pre-operative physiotherapy in patients undergoing hip arthroplasty does not improve impairment and health-related quality of life after intervention. Physiotherapy and educational therapy may be useful for end-stage osteoarthritis.

Ex vivo-transduced autologous skin fibroblasts expressing human Lim mineralization protein-3 efficiently form new bone in animal models.

Local gene transfer of the human Lim mineralization protein (LMP), a novel intracellular positive regulator of the osteoblast differentiation program, can induce efficient bone formation in rodents. To develop a clinically relevant gene therapy approach to facilitate bone healing, we have used primary dermal fibroblasts transduced ex vivo with Ad.LMP-3 and seeded on a hydroxyapatite/collagen matrix prior to autologous implantation. Here, we demonstrate that genetically modified autologous dermal fibroblasts expressing Ad.LMP-3 are able to induce ectopic bone formation following implantation of the matrix into mouse triceps and paravertebral muscles. Moreover, implantation of the Ad.LMP-3-modified dermal fibroblasts into a rat mandibular bone critical size defect model results in efficient healing, as determined by X-rays, histology and three-dimensional microcomputed tomography (3DμCT). These results demonstrate the effectiveness of the non-secreted intracellular osteogenic factor LMP-3 in inducing bone formation in vivo. Moreover, the utilization of autologous dermal fibroblasts implanted on a biomaterial represents a promising approach for possible future clinical applications aimed at inducing new bone formation.

Percutaneous acetabuloplasty for metastatic acetabular lesions

BackgroundOsteolytic metastases around the acetabulum are frequent in tumour patients, and may cause intense and drug-resistant pain of the hip. These lesions also cause structural weakening of the pelvis, limping, and poor quality of life. Percutaneous acetabuloplasty is a mini-invasive procedure for the management of metastatic lesions due to carcinoma of the acetabulum performed in patients who cannot tolerate major surgery, or in patients towards whom radiotherapy had already proved ineffective.MethodsWe report a retrospective study in 25 such patients (30 acetabuli) who were evaluated before and after percutaneous acetabuloplasty, with regard to pain, mobility of the hip joint, use of analgesics, by means of evaluation forms: Visual Analog Scale, Harris Hip Score, Western Ontario and McMaster Universities Index of Osteoarthritis (WOMAC), Eastern Cooperative Oncology Group (ECOG). The results obtained were analysed using the χ2 Test and Fishers exact test. Significance was sent at P < 0.05.ResultsMarked clinical improvement was observed in all patients during the first six post-operative months, with gradual a worsening thereafter from deterioration of their general condition.Complete pain relief was achieved in 15 of our 25 (59%) of patients, and pain reduction was achieved in the remaining 10 (41%) patients. The mean duration of pain relief was 7.3 months. Pain recurred in three patients (12%) between 2 weeks to 3 months. No major complications occurred. There was transient local pain in most cases, and 2 cases of venous injection of cement without clinical consequences.ConclusionPercutaneous acetabuloplasty is effective in improving the quality of life of patients with osteolytic bone tumours, even though the improvement is observed during the first 6 months only. It can be an effective aid to chemo- and radiotherapy in the management of acetabular metastases.

Bone integration of new stemless hip implants (proxima vs. nanos). A DXA study: preliminary results

The development of short femoral prostheses has the advantage to preserve bone and soft tissues, restore hip geometry, permit mini-invasive techniques and allow quickly return to an active life, but very few studies described bone reaction to these new designed prostheses. The aim of the present study was to evaluate the osseointegration of two different partial neck retained stemless hip prosthesis at one year after surgery, measured by the changes of periprosthetic bone mineral density (BMD) in 5 regions of interest (ROIs) using a dual-energy X ray absorptiometry (DXA) device. The signs of stress-shielding were evaluated by standard radiographs. Thirty-two uncemented primary total hip arthroplasty (THA) patients allocated into 2 groups were evaluated. In the first group (n=19) a Proxima (De-Puy-J&J) hip stem was implanted. In the second group (n=12) a Nanos (Smith & Nephew) hip stem was used. We found that both the implants preserve metaphyseal bone stock and increase periprosthetic BMD. In Nanos prostheses a significant higher BMD values were observed in region of interest (ROI) 3 and 4 (p<0.05). No differences were found in ROIs 1, 2, and 5. Proxima stem seem to produce a physiological strain distribution in the femur. No signs of stress-shielding were present in both the implants. In conclusion, this preliminary DXA analysis showed a physiological integration of both the stems that reproduces the biomechanical stress of proximal femur. New designed short stem implants showed optimal osseointegration after one year, and therefore appears an excellent alternative to traditional long stem hip prostheses.

Lim Mineralization Protein 3 Induces the Osteogenic Differentiation of Human Amniotic Fluid Stromal Cells through Kruppel-Like Factor-4 Downregulation and Further Bone-Specific Gene Expression

Multipotent mesenchymal stem cells with extensive self-renewal properties can be easily isolated and rapidly expanded in culture from small volumes of amniotic fluid. These cells, namely, amniotic fluid-stromal cells (AFSCs), can be regarded as an attractive source for tissue engineering purposes, being phenotypically and genetically stable, plus overcoming all the safety and ethical issues related to the use of embryonic/fetal cells. LMP3 is a novel osteoinductive molecule acting upstream to the main osteogenic pathways. This study is aimed at delineating the basic molecular events underlying LMP3-induced osteogenesis, using AFSCs as a cellular model to focus on the molecular features underlying the multipotency/differentiation switch. For this purpose, AFSCs were isolated and characterized in vitro and transfected with a defective adenoviral vector expressing the human LMP3. LMP3 induced the successful osteogenic differentiation of AFSC by inducing the expression of osteogenic markers and osteospecific transcription factors. Moreover, LMP3 induced an early repression of the kruppel-like factor-4, implicated in MSC stemness maintenance. KLF4 repression was released upon LMP3 silencing, indicating that this event could be reasonably considered among the basic molecular events that govern the proliferation/differentiation switch during LMP3-induced osteogenic differentiation of AFSC.

Synthetic Biomimetic Nanostructured Hydroxyapatite

The incorporation of magnesium ions into the hydroxyapatite structure, which is of great interest for the developing of artificial bone, was performed starting from a wet chemical synthesis using magnesium chloride as Mg source. Different doping extents were attempted, four powders were produced and characterized in term of morphology, composition, solubility, thermal resistance,etc. in comparison with stoichiometric HA. In vitro tests with mesenchimal stem cells (MSCs) and human osteoblast like cells MG-63 cells were performed with the powder characterized with a biological-like doping of 5%Mg. The same powder was used, in form of granules, to carry out in vivo test by filling a defect in the femur on New Zealand White rabbits. All the tests showed better performance of the Mg doped apatite compared to stoichiometric HA, in agreement with the chemico-physical features of the material.

Potential therapeutic targets for ALS: MIR206, MIR208b and MIR499 are modulated during disease progression in the skeletal muscle of patients

Amyotrophic lateral sclerosis (ALS) is characterized by the progressive loss of motor neurons followed by muscle weakness, paralysis and death. The disease progression is extremely variable among patients, and reliable prognostic markers have not been identified. The aim of the study was to functionally characterize selected genes and microRNAs acting in the skeletal muscle of ALS patients, taking into account the duration and evolution of the disease, in order to obtain information regarding the muscle response to ALS progression. This prospective, longitudinal study enrolled 14 ALS patients and 24 age- and sex-matched healthy controls. Gene expression and histological analysis indicated an increase of MIR208B and MIR499 levels and the predominance of slow fibres, respectively, in the muscles of patients with a slower disease progression. A decreased expression of MIR206 and increased levels of HDAC4, during the progression of the disease were also observed. Taken together, our data suggest that the molecular signalling that regulates re-innervation and muscle regeneration is hampered during the progression of skeletal muscle impairment in ALS. This could provide precious hints towards defining prognostic protocols, and designing novel tailored therapeutic approaches, to improve ALS patients’ care and delay disease progression.