Polyelectrolyte-coated mesoporous bioactive glasses via layer-by-layer deposition for sustained co-delivery of therapeutic ions and drugs

In the field of bone regeneration, considerable attention has been addressed towards the use of mesoporous bioactive glasses (MBGs), as multifunctional therapeutic platforms for advanced medical devices. In fact, their extremely high exposed surface area and pore volume allow to load and the release of several drugs, while their framework can be enriched with specific therapeutic ions allowing to boost the tissue regeneration. However, due to the open and easily accessible mesopore structure of MBG, the release of the incorporated therapeutic molecules shows an initial burst effect leading to unsuitable release kinetics. Hence, a still open challenge in the design of drug delivery systems based on MBGs is the control of their release behavior. In this work, Layer-by-layer (LbL) deposition of polyelectrolyte multi-layers was exploited as a powerful and versatile technique for coating the surface of Cu-substituted MBG nanoparticles with innovative multifunctional drug delivery systems for co-releasing of therapeutic copper ions (exerting pro-angiogenic and anti-bacterial effects) and an anti-inflammatory drug (ibuprofen). Two different routes were investigated: in the first strategy, chitosan and alginate were assembled by forming the multi-layered surface, and, successively, ibuprofen was loaded by incipient wetness impregnation, while in the second approach, alginate was replaced by ibuprofen, introduced as polyelectrolyte layer. Zeta-potential, TGA and FT-IR spectroscopy were measured after the addition of each polyelectrolyte layer, confirming the occurrence of the stepwise deposition. In addition, the in vitro bioactivity and the ability to modulate the release of the cargo were evaluated. The polyelectrolyte coated-MBGs were proved to retain the peculiar ability to induce hydroxyapatite formation after 7 days of soaking in Simulated Body Fluid. Both copper ions and ibuprofen were co-released over time, showing a sustained release profile up to 14 days and 24 h, respectively, with a significantly lower burst release compared to the bare MBG particles

Hybrid injectable platforms for the in situ delivery of therapeutic ions from mesoporous glasses

Copper-containing bioactive glasses (Cu-MBGs) are attracting increasing interest as multifunctional agents for hard and soft tissue healing due to the ability of released copper ions to stimulate osteogenesis as well as angiogenesis and to impart anti-bacterial properties. The conjugation of these nanomaterials with a vehicle phase based on thermosensitive hydrogels represents an effective strategy to design non-invasive injectable devices for the in situ delivery of therapeutic ions from MBGs. In this contribution, Cu-containing MBGs were prepared by an aerosol-assisted spray-drying method (MBG_Cu 2%_SD) in the form of microspheres (surface area of ca 220m2 g−1) and through a sol-gel synthesis (MBG_Cu 2% _SG) in the form of spheroidal nanoparticles (surface area above 700m2 g−1). Both Cu-containing samples were able to release copper ions, although with different rates and percentage release. MBG_Cu 2%_SG released the total incorporated amount of Cu ions with a faster kinetics compared to MBG_Cu 2%_SD, that released approximately the 60% of copper. Cu-MBGs were incorporated with a final concentration of 20 mg/mL into a thermosensitive sol-gel system consisting of a novel amphiphilic poly(ether urethane) based on a commercialy available Poloxamer 407 (P407), with improved gelation ability, mechanical strength and stability in aqueous solution with respect to native P407. Cu-MBG-loaded hydrogels were characterised in terms of sol-to-gel transition temperature and time, injectability and stability in aqueous environment at 37 °C. The hybrid formulations showed fast gelation in physiological conditions (1 mL underwent complete sol-to-gel transition within 3–5 min at 37 °C) and injectability in a wide range of temperatures (5–37 °C) through different needles (inner diameter in the range 0.6–1.6 mm)

Sr-containing mesoporous bioactive glasses bio-functionalized with recombinant ICOS-Fc: An in vitro study

Osteoporotic bone fractures represent a critical clinical issue and require personalized and specific treatments in order to stimulate compromised bone tissue regeneration. In this clinical context, the development of smart nano-biomaterials able to synergistically combine chemical and biological cues to exert specific therapeutic effects (i.e., pro-osteogenic, anti-clastogenic) can allow the design of effective medical solutions. With this aim, in this work, strontium-containing mesoporous bioactive glasses (MBGs) were bio-functionalized with ICOS-Fc, a molecule able to reversibly inhibit osteoclast activity by binding the respective ligand (ICOS-L) and to induce a decrease of bone resorption activity. N2 adsorption analysis and FT-IR spectroscopy were used to assess the successful grafting of ICOS-Fc on the surface of Sr-containing MBGs, which were also proved to retain the peculiar ability to release osteogenic strontium ions and an excellent bioactivity after functionalization. An ELISA-like assay allowed to confirm that grafted ICOS-Fc molecules were able to bind ICOS-L (the ICOS binding ligand) and to investigate the stability of the amide binding to hydrolysis in aqueous environment up to 21 days. In analogy to the free form of the molecule, the inhibitory effect of grafted ICOS-Fc on cell migratory activity was demonstrated by using ICOSL positive cell lines and the ability to inhibit osteoclast differentiation and function was confirmed by monitoring the differentiation of monocyte-derived osteoclasts (MDOCs), which revealed a strong inhibitory effect, also proven by the downregulation of osteoclast differentiation genes. The obtained results showed that the combination of ICOS-Fc with the intrinsic properties of Sr-containing MBGs represents a very promising approach to design personalized solutions for patients affected by compromised bone remodeling (i.e., osteoporosis fractures)

Natural history and risk factors for diabetic kidney disease in patients with T2D: lessons from the AMD-annals

The Associazione Medici Diabetologi (AMD) annals initiative is an ongoing observational survey promoted by AMD. It is based on a public network of about 700 Italian diabetes clinics, run by specialists who provide diagnostic confirmation and prevention and treatment of diabetes and its complications. Over the last few years, analysis of the AMD annals dataset has contributed several important insights on the clinical features of type-2 diabetes kidney disease and their prognostic and therapeutic implications. First, non-albuminuric renal impairment is the predominant clinical phenotype. Even though associated to a lower risk of progression compared to overt albuminuria, it contributes significantly to the burden of end-stage renal disease morbidity. Second, optimal blood pressure control provides significant but incomplete renal protection. It reduces albuminuria but there may be a J curve phenomenon with eGFR at very low blood pressure values. Third, hyperuricemia and diabetic hyperlipidemia, namely elevated triglycerides and low HDL cholesterol, are strong independent predictors of chronic kidney disease (CKD) onset in diabetes, although the pathogenetic mechanisms underlying these associations remain uncertain. Fourth, the long-term intra-individual variability in HbA1c, lipid parameters, uric acid and blood pressure plays a greater role in the appearance and progression of CKD than the absolute value of each single variable. These data help clarify the natural history of CKD in patients with type 2 diabetes and provide important clues for designing future interventional studies

Blood pressure control in Italy: analysis of clinical data from 2005-2011 surveys on hypertension

Introduction: Blood pressure (BP) control is poorly achieved in hypertensive patients, worldwide. Aim: We evaluated clinic BP levels and the rate of BP control in hypertensive patients included in observational studies and clinical surveys published between 2005 and 2011 in Italy. Methods: We reviewed the medical literature to identify observational studies and clinical surveys on hypertension between January 2005 and June 2011, which clearly reported information on clinic BP levels, rates of BP control, proportions of treated and untreated patients, who were followed in different clinical settings (mostly in general practice, and also in outpatient clinics and hypertension centres). Results: The overall sample included 158 876 hypertensive patients (94 907 women, mean age 56.6 +/- 9.6 years, BMI 27.2 +/- 4.2 kg/m(2), known duration of hypertension 90.2 +/- 12.4 months). In the selected studies, average SBP and DBP levels were 145.7 +/- 15.9 and 87.5 +/- 9.7 mmHg, respectively; BP levels were higher in patients followed in hypertension centres (n = 10 724, 6.7%; 146.5 +/- 17.3/88.5 +/- 10.3 mmHg) than in those followed by general practitioners (n = 148 152, 93.3%; 143.5 +/- 13.9/84.8 +/- 8.9 mmHg; P < 0.01). More than half of the patients were treated (n = 91 318, 57.5%); among treated hypertensive patients, only 31 727 (37.0%) had controlled BP levels. Conclusion: The present analysis confirmed inadequate control of BP in Italy, independently of the clinical setting. Although some improvement was noted compared with a similar analysis performed between 1995 and 2005, these findings highlight the need for a more effective clinical management of hypertension

Blood pressure control in Italy: analysis of clinical data from 2005-2011 surveys on hypertension

INTRODUCTION: Blood pressure (BP) control is poorly achieved in hypertensive patients, worldwide. AIM: We evaluated clinic BP levels and the rate of BP control in hypertensive patients included in observational studies and clinical surveys published between 2005 and 2011 in Italy. METHODS: We reviewed the medical literature to identify observational studies and clinical surveys on hypertension between January 2005 and June 2011, which clearly reported information on clinic BP levels, rates of BP control, proportions of treated and untreated patients, who were followed in different clinical settings (mostly in general practice, and also in outpatient clinics and hypertension centres). RESULTS: The overall sample included 158 876 hypertensive patients (94 907 women, mean age 56.6 ± 9.6 years, BMI 27.2 ± 4.2 kg/m(2), known duration of hypertension 90.2 ± 12.4 months). In the selected studies, average SBP and DBP levels were 145.7 ± 15.9 and 87.5 ± 9.7 mmHg, respectively; BP levels were higher in patients followed in hypertension centres (n = 10 724, 6.7%; 146.5 ± 17.3/88.5 ± 10.3 mmHg) than in those followed by general practitioners (n = 148 152, 93.3%; 143.5 ± 13.9/84.8 ± 8.9 mmHg; P < 0.01). More than half of the patients were treated (n = 91 318, 57.5%); among treated hypertensive patients, only 31 727 (37.0%) had controlled BP levels. CONCLUSION: The present analysis confirmed inadequate control of BP in Italy, independently of the clinical setting. Although some improvement was noted compared with a similar analysis performed between 1995 and 2005, these findings highlight the need for a more effective clinical management of hypertension