Osteogenic-angiogenic coupled response of cobalt-containing mesoporous bioactive glasses in vivo

The incorporation of cobalt ions into the composition of bioactive glasses has emerged as a strategy of interest for bone regeneration purposes. In the present work, we have designed a set of bioactive mesoporous glasses SiO2-CaO-P2O5-CoO (Co-MBGs) with different amounts of cobalt. The physicochemical changes introduced by the Co2+ ion, the in vitro effects of Co-MBGs on preosteoblasts and endothelial cells and their in vivo behaviour using them as bone grafts in a sheep model were studied. The results show that Co2+ ions neither destroy mesoporous ordering nor inhibit in vitro bioactive behaviour, exerting a dual role as network former and modifier for CoO concentrations above 3 % mol. On the other hand, the activity of Co-MBGs on MC3T3-E1 preosteoblasts and HUVEC vascular endothelial cells is dependent on the concentration of CoO present in the glass. For low Co-MBGs concentrations (1mg/ml) cell viability is not affected, while the expression of osteogenic (ALP, RUNX2 and OC) and angiogenic (VEGF) genes is stimulated. For Co-MBGs concentration of 5 mg/ml, cell viability decreases as a function of the CoO content. In vivo studies show that the incorporation of Co2+ ions to the MBGs improves the bone regeneration activity of these materials, despite the deleterious effect that this ion has on bone-forming cells for any of the Co-MBG compositions studied. This contradictory effect is explained by the marked increase in angiogenesis that takes place inside the bone defect, leading to an angiogenesis-osteogenesis coupling that compensates for the partial decrease in osteoblast cells. STATEMENT OF SIGNIFICANCE: The development of new bone grafts implies to address the need for osteogenesis-angiogenesis coupling that allows bone regeneration with viable tissue in the long term. In this sense the incorporation of cobalt ions into the composition of bioactive glasses has emerged as a strategy of great interest in this field. Due to the potential cytotoxic effect of cobalt ions, there is an important controversy regarding the suitability of their incorporation in bone grafts. In this work, we address this controversy after the implantation of cobalt-doped mesoporous bioactive glasses in a sheep model. The incorporation of cobalt ions in bioactive glasses improves the bone regeneration ability of these bone grafts, due to enhancement of the angiogenesis-osteogenesis coupling.

Conditional performance factors in padel players: a mini review

Introduction

Padel's global growth highlights its technical complexity. The first publications focus on the physical aspects of padel, using methods that evaluate players' endurance, strength, speed, and range of motion, while the quantification of load, using internal and external indicators, is crucial for performance optimization, whilst taking into account athletes' profiles and levels. Therefore, the objective entailed analyzing the scientific literature about the conditional demands in competition within padel players from different levels.

Methods

Data was collected from various databases and after the selection process, the information was analyzed in mini review.

Results

The mini review shows that the conditional demands are categorized into internal and external load to try to obtain reference values that may define the demands of padel based on the competitive level and sex. Regarding the internal load, the heart rate (HR)% of the padel players from different levels is around 70%-80% of the HR Max. Regarding the external load, in femalés categories, a greater number of strokes are made per point which entails a longer duration in the points.

Conclusions

Padel research usually analyses physical demands using internal and external loading. HR% values (70%-80% HR Max) are consistent across studies. There is variation between variables such as strokes per point, and contextual factors affect the metrics. Further exploration is vital to obtain comprehensive benchmarks and understand the demands of this sport.

Desing and comparison of bone substitutes. Study of in vivo behavior in a rabbit model

AIM

Compare bone formation capacity in vivo of two types of biomaterials designed as bone substitutes with respect to iliac crest autograft, one based on carbonate hydroxyapatites and the other one on bioactive mesoporous glass.

MATERIALS AND METHODS

Experimental study consisting on 14 adult female New Zeland rabbits where a critical defect was made in the rabbit radius bone. The sample was divided into four groups: defect without material, with iliac crest autograft, with carbonatehydroxyapatite support, and with bioactive mesoporous glass support. Serial X-ray studies were carried out at 2, 4, 6 and 12 weeks and a microCT study at euthanasia at 6 and 12 weeks.

RESULTS

In the X-ray study, autograft group showed the highest bone formation scores. Both groups of biomaterials presented bone formation similar and greater than the defect without material, but always less than in the autograft group. The results of the microCT study showed the largest bone volume in the study area in the autograft group. The groups with bone substitutes presented greater bone volume than the group without material but always less than in the autograft group.

CONCLUSION

Both supports seem to promote bone formation but are not capable of reproducing the characteristics of autograft. Due to their different macroscopic characteristics, each one could be suitable for a different type of defect.

[Translated article] Design and comparison of bone substitutes. Study of in vivo behaviour in a rabbit model

AIM

To compare the in vivo bone formation capacity of of biomaterials designed as bone substitutes with respect to iliac crest autograft, one based on carbonate hydroxiapatite and the other one on bioactive mesoporous glass.

MATERIALS AND METHODS

Experimental study consisting on 14 adult female New Zeland rabbits where a critical defect was made in the rabbit radius bone. The sample was divided into four groups: defect without material, with iliac crest autograft, with carbonatehydroxyapatite scaffold, and with bioactive mesoporous glass scaffold. Serial X-ray studies were carried out at 2, 4, 6 and 12 weeks and a microCT study at euthanasia at 6 and 12 weeks.

RESULTS

In the X-ray study, autograft group showed the highest bone formation scores. Both groups of biomaterials presented bone formation similar and greater than the defect without material, but always less than in the autograft group. The results of the microCT study showed the largest bone volume in the study area in the autograft group. The groups with bone substitutes presented greater bone volume than the group without material but always less than the autograft group.

CONCLUSION

Both scaffolds seem to promote bone formation but are not capable of reproducing the characteristics of autograft. Due to their different macroscopic characteristics, each one could be suitable for a different type of defect.

Antibiotic delivery from bone-targeted mesoporous silica nanoparticles for the treatment of osteomyelitis caused by methicillin-resistant Staphylococcus aureus

Osteomyelitis is a hard-to-treat infection of the bone and bone marrow that is mainly caused by Staphylococcus aureus, with an increasing incidence of methicillin-resistant S. aureus (MRSA). Owing to the aggressiveness of these bacteria in colonizing and destroying the bone, systemic antibiotic treatments fail to eradicate the infection. Instead, it normally entails surgery to remove the dead or infected bone. In this work, we report bone-targeted mesoporous silica nanoparticles for the treatment of osteomyelitis. The nanoparticles have been engineered with a functional gelatine/colistin coating able to hamper premature release from the mesopores while effectively disaggregating the bacterial biofilm. Because antibiotic resistance is a global emergency, we have designed two sets of identical nanoparticles, carrying each of them a clinically relevant antibiotic, that have demonstrated to have synergistic effect. The bone-targeted nanoparticles have been thoroughly evaluated in vitro and in vivo, obtaining a notable reduction of the amount of bacteria in the bone in just 24 h after only one dose, and paving the way for localized, nanoparticle-mediated treatment of MRSA-caused osteomyelitis. STATEMENT OF SIGNIFICANCE: In this work, we propose the use of bone-targeted mesoporous silica nanoparticles to address S. aureus-caused osteomyelitis that render synergistic therapeutic effect via multidrug delivery. Because the bacterial biofilm is responsible for an aggressive surgical approach and prolonged antibiotic treatment, the nanoparticles have been functionalized with a functional coating able to both disaggregate the biofilm, hamper premature antibiotic release and protect the intact bone. These engineered nanoparticles are able to effectively target bone tissue both in vitro and in vivo, showing high biocompatibility and elevated antibacterial effect.

ZnO-mesoporous glass scaffolds loaded with osteostatin and mesenchymal cells improve bone healing in a rabbit bone defect

The use of 3D scaffolds based on mesoporous bioactive glasses (MBG) enhanced with therapeutic ions, biomolecules and cells is emerging as a strategy to improve bone healing. In this paper, the osteogenic capability of ZnO-enriched MBG scaffolds loaded or not with osteostatin (OST) and human mesenchymal stem cells (MSC) was evaluated after implantation in New Zealand rabbits. Cylindrical meso-macroporous scaffolds with composition (mol %) 82.2SiO₂-10.3CaO-3.3P₂O₅-4.2ZnO (4ZN) were obtained by rapid prototyping and then, coated with gelatin for easy handling and potentiating the release of inorganic ions and OST. Bone defects (7.5 mm diameter, 12 mm depth) were drilled in the distal femoral epiphysis and filled with 4ZN, 4ZN + MSC, 4ZN + OST or 4ZN + MSC + OST materials to evaluate and compare their osteogenic features. Rabbits were sacrificed at 3 months extracting the distal third of bone specimens for necropsy, histological, and microtomography (µCT) evaluations. Systems investigated exhibited bone regeneration capability. Thus, trabecular bone volume density (BV/TV) values obtained from µCT showed that the good bone healing capability of 4ZN was significantly improved by the scaffolds coated with OST and MSC. Our findings in vivo suggest the interest of these MBG complete systems to improve bone repair in the clinical practice.

Osteostatin potentiates the bioactivity of mesoporous glass scaffolds containing Zn2+ ions in human mesenchymal stem cells

There is an urgent need of biosynthetic bone grafts with enhanced osteogenic capacity. In this study, we describe the design of hierarchical meso-macroporous 3D-scaffolds based on mesoporous bioactive glasses (MBGs), enriched with the peptide osteostatin and Zn2+ ions, and their osteogenic effect on human mesenchymal stem cells (hMSCs) as a preclinical strategy in bone regeneration. The MBG compositions investigated were 80%SiO2-15%CaO-5%P2O5 (in mol-%) Blank (BL), and two analogous glasses containing 4% ZnO (4ZN) and 5% ZnO (5ZN). By using additive fabrication techniques, scaffolds exhibiting hierarchical porosity: mesopores (around 4 nm), macropores (1-600 μm) and big channels (∼1000 μm), were prepared. These MBG scaffolds with or without osteostatin were evaluated in hMCSs cultures. Zinc promoted hMSCs colonization (both the surface and inside) of MBG scaffolds. Moreover, Zn2+ ions and osteostatin together, but not independently, in the scaffolds were found to induce the osteoblast differentiation genes runt related transcription factor-2 (RUNX2) and alkaline phosphatase (ALP) in hMSCs after 7 d of culture in the absence of an osteogenic differentiation-promoting medium. These results add credence to the combined use of zinc and osteostatin as an effective strategy for bone regeneration applications. STATEMENT OF SIGNIFICANCE: Mesoporous bioactive glasses (MBGs) are bioceramics whose unique properties make them excellent materials for bone tissue engineering. Physico-chemical characterization of MBGs as scaffolds made by rapid prototyping, doped with zinc (potential osteogenic, angiogenic and bactericidal ion) and loaded with osteostatin (osteogenic peptide) are described. These Zn-MBGs scaffolds showed 3D hierarchical meso-macroporous structure that enables to host and release osteostatin. When decorated with human mesenchymal stem cells (hMSCs), MBGs scaffoldsenriched with both zinc and osteostatin exhibited a synergistic effect to enhance hMSCs growth, and also hMSCs osteogenic differentiationwithout addition of other osteoblastic differentiation factors to the culture medium. This novel strategy has a great potential for use in bone tissue engineering.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Parathyroid hormone-related protein exhibits antioxidant features in osteoblastic cells through its N-terminal and osteostatin domains

Objectives

Oxidative stress plays a major role in the onset and progression of involutional osteoporosis. However, classical antioxidants fail to restore osteoblast function. Interestingly, the bone anabolism of parathyroid hormone (PTH) has been shown to be associated with its ability to counteract oxidative stress in osteoblasts. The PTH counterpart in bone, which is the PTH-related protein (PTHrP), displays osteogenic actions through both its N-terminal PTH-like region and the C-terminal domain.

Methods

We examined and compared the antioxidant capacity of PTHrP (1-37) with the C-terminal PTHrP domain comprising the 107-111 epitope (osteostatin) in both murine osteoblastic MC3T3-E1 cells and primary human osteoblastic cells.

Results

We showed that both N- and C-terminal PTHrP peptides at 100 nM decreased reactive oxygen species production and forkhead box protein O activation following hydrogen peroxide (H₂O₂)-induced oxidation, which was related to decreased lipid oxidative damage and caspase-3 activation in these cells. This was associated with their ability to restore the deleterious effects of H₂O₂ on cell growth and alkaline phosphatase activity, as well as on the expression of various osteoblast differentiation genes. The addition of Rp-cyclic 3′,5′-hydrogen phosphorothioate adenosine triethylammonium salt (a cyclic 3',5'-adenosine monophosphate antagonist) and calphostin C (a protein kinase C inhibitor), or a PTH type 1 receptor antagonist, abrogated the effects of N-terminal PTHrP, whereas protein phosphatase 1 (an Src kinase activity inhibitor), SU1498 (a vascular endothelial growth factor receptor 2 inhibitor), or an anti osteostatin antiserum, inhibited the effects of C-terminal PTHrP.

Conclusion

These findings indicate that the antioxidant properties of PTHrP act through its N- and C-terminal domains and provide novel insights into the osteogenic action of PTHrP.

Cite this article: S. Portal-Núñez, J. A. Ardura, D. Lozano, I. Martínez de Toda, M. De la Fuente, G. Herrero-Beaumont, R. Largo, P. Esbrit. Parathyroid hormone-related protein exhibits antioxidant features in osteoblastic cells through its N-terminal and osteostatin domains. Bone Joint Res 2018;7:58–68. DOI: 10.1302/2046-3758.71.BJR-2016-0242.R2.

83 Effect of Synchronization Treatment and Estrus Expression on Conception Rates and Pregnancy Losses in Recipients Receiving In Vitro-Produced Embryos

The objective of this study was to evaluate the effect of synchronization treatment and oestrus expression on conception rates and pregnancy losses in recipients receiving in vitro-produced (IVP) embryos. Crossbred beef cows (n = 407) with a corpus luteum (CL) determined by ultrasonography and body condition between 2.5 and 4.5 (1 to 5 scale) received a progesterone-releasing device (DIB 0.5 g, Zoetis, Argentina) and 2 mg of oestradiol benzoate (EB, Gonadiol, Zoetis) on Day 0 and were randomly allocated to 1 of 2 treatments. Recipients in the Conventional group (n = 201) had their devices removed and received 500 µg of cloprostenol (PGF, Ciclase, Zoetis), 0.5 mg of oestradiol cypionate (ECP, Cipiosyn, Zoetis), and 400 IU of eCG (Novormón, Zoetis) on Day 8. Recipients in the J-Synch group (n = 206) had their devices removed and received PGF and eCG on Day 6. All recipients were tail-painted at device removal to determine the presence of oestrus on Day 10 (a.m.) in the Conventional group and on Day 9 (a.m.) in the J-Synch group. All recipients not in oestrus in both groups received 100 µg of gonadorelin (GnRH, Ovurelin, Bayer, New Zealand) at that time. In addition, the paint was observed again in the p.m. and it was recorded. Recipients were examined by ultrasonography 7 days after oestrus or GnRH treatment (Day 16 in the J-Synch group and Day 17 in the Conventional group) and those with a CL = 16 mm in diameter received an IVP fresh embryo non-surgically. Pregnancy was determined by ultrasonography 23 and 53 days after embryo transfer and calving rates were recorded. Data were analysed using generalized linear models for binary data and a logit link (InfoStat, https://www.infostat.com.ar/). The proportion of recipients transferred was higher (P < 0.05) in the Conventional group (90.0%, 180/201) than in the J-Synch group (83.5%, 172/206). However, conception rates and the percentage of recipients pregnant/treated did not differ between groups (Conventional: 36.6%; 66/180 and 32.8%; 66/201 v. J-Synch: 39.0%; 67/172 and 32.5%; 67/206). Although no interaction was detected between treatments and oestrus expression, the conception rate was higher (P < 0.05) in recipients showing oestrus (39.1%, 124/317) than in those not showing oestrus (25.7%, 9/35). Furthermore, embryo/fetal losses between 30 and 60 days were not affected by the synchronization treatment (P > 0.11), but they were lower (P < 0.01) in recipients showing oestrus (5.6%, 7/124) than in those not showing oestrus (66.7%, 6/9). Similarly, fetal losses between 60 days and calving tended to be lower (P < 0.06) in recipients showing oestrus (20.5%, 24/117) than in those not showing oestrus (66.7%; 2/3). Calving rates were higher in recipients showing oestrus (29.3%, 93/317) than in those not showing oestrus (2.9%, 1/35; P < 0.01). In conclusion, although both synchronization treatments performed similarly, recipients not showing oestrus after progesterone device removal had lower conception rates and higher pregnancy losses than those showing oestrus at the expected time after treatment.

A novel visible light responsive nanosystem for cancer treatment

A novel singlet-oxygen sensitive drug delivery nanocarrier able to release its cargo after exposure to visible (Vis) light from a common lamp is presented. This nanodevice is based on mesoporous silica nanoparticles (MSN) decorated with porphyrin-caps grafted via reactive oxygen species (ROS)-cleavable linkages. In the presence of Vis light porphyrin-nanocaps produce singlet oxygen molecules that break the sensitive-linker, which triggers pore uncapping and therefore allows the release of the entrapped cargo (topotecan, TOP). This new system takes advantage of the non-toxicity and greater penetration capacity of Vis radiation and a double antitumor effect due to the drug release and the ROS production. In vitro tests with HOS osteosarcoma cancer cells reveal that TOP is able to be released in a controlled fashion inside the tumor cells. This research work constitutes a proof of concept that opens up promising expectations in the search for new alternatives for the treatment of cancer.

Evaluation of bacterial adherence of clinical isolates of Staphylococcus sp. using a competitive model: An in vitro approach to the "race for the surface" theory

Objectives

Implant-related infection is one of the most devastating complications in orthopaedic surgery. Many surface and/or material modifications have been developed in order to minimise this problem; however, most of the in vitro studies did not evaluate bacterial adhesion in the presence of eukaryotic cells, as stated by the ‘race for the surface’ theory. Moreover, the adherence of numerous clinical strains with different initial concentrations has not been studied.

Methods

We describe a method for the study of bacterial adherence in the presence of preosteoblastic cells. For this purpose we mixed different concentrations of bacterial cells from collection and clinical strains of staphylococci isolated from implant-related infections with preosteoblastic cells, and analysed the minimal concentration of bacteria able to colonise the surface of the material with image analysis.

Results

Our results show that clinical strains adhere to the material surface at lower concentrations than collection strains. A destructive effect of bacteria on preosteoblastic cells was also detected, especially with higher concentrations of bacteria.

Conclusions

The method described herein can be used to evaluate the effect of surface modifications on bacterial adherence more accurately than conventional monoculture studies. Clinical strains behave differently than collection strains with respect to bacterial adherence.

Cite this article: M. Martinez-Perez, C. Perez-Jorge, D. Lozano, S. Portal-Nuñez, R. Perez-Tanoira, A. Conde, M. A. Arenas, J. M. Hernandez-Lopez, J. J. de Damborenea, E. Gomez-Barrena, P. Esbrit, J. Esteban. Evaluation of bacterial adherence of clinical isolates of Staphylococcus sp. using a competitive model: An in vitro approach to the “race for the surface” theory. Bone Joint Res 2017;6:315–322. DOI: 10.1302/2046-3758.65.BJR-2016-0226.R2.

Self-immolative polymers as novel pH-responsive gate keepers for drug delivery

A novel pH-sensitive nanocarrier based on mesoporous silica nanoparticles with self-immolative polymers blocking the pore openings is presented.

Correction: Self-immolative polymers as novel pH-responsive gate keepers for drug delivery

Correction for ‘Self-immolative polymers as novel pH-responsive gate keepers for drug delivery’ by M. Gisbert-Garzaran et al., RSC Adv., 2017, 7, 132–136.

Intradomiciliary and peridomiciliary captures of sand flies (Diptera: Psychodidae) in the leishmaniasis endemic area of Chapare province, tropic of Cochabamba, Bolivia

In South America, cutaneous leishmaniasis is the most frequent clinical form of leishmaniasis. Bolivia is one of the countries with higher incidence, with 33 cases per 100,000 individuals, and the disease is endemic in 70% of the territory. In the last decade, the number of cases has increased, the age range has expanded, affecting children under 5 years old, and a similar frequency between men and women is found. An entomological study with CDC light traps was conducted in three localities (Chipiriri, Santa Elena and Pedro Domingo Murillo) of the municipality of Villa Tunari, one of the main towns in the Chapare province (Department of Cochabamba, Bolivia). A total of 16 specimens belonging to 6 species of the genus Lutzomyia were captured: Lu. aragaoi, Lu. andersoni, Lu. antunesi, Lu. shawi, Lu. yuilli yuilli and Lu. auraensis. Our results showed the presence of two incriminated vectors of leishmaniasis in an urbanized area and in the intradomicile. More entomological studies are required in the Chapare province to confirm the role of vector sand flies, the intradomiciliary transmission of the disease and the presence of autochthonous cases of cutaneous leishmaniasis.

Selective topotecan delivery to cancer cells by targeted pH-sensitive mesoporous silica nanoparticles

Topotecan targeted pH-sensitive delivery system based in mesoporous silica nanoparticles coated with a multifunctional biopolymer coating for cancer therapy.

An update on the use of melatonin as a stroke therapeutic

Delivery of melatonin and targeting melatonin receptors pose as neuroprotective strategies for stroke therapy. The potential of melatonin-based therapeutics for clinical application in stroke patients requires translational research to guide the conduct of clinical trials. We review recent preclinical and clinical data that support the use of melatonin for stroke.

Fabrication of novel Si-doped hydroxyapatite/gelatine scaffolds by rapid prototyping for drug delivery and bone regeneration

Porous 3-D scaffolds consisting of gelatine and Si-doped hydroxyapatite were fabricated at room temperature by rapid prototyping. Microscopic characterization revealed a highly homogeneous structure, showing the pre-designed porosity (macroporosity) and a lesser in-rod porosity (microporosity). The mechanical properties of such scaffolds are close to those of trabecular bone of the same density. The biological behavior of these hybrid scaffolds is greater than that of pure ceramic scaffolds without gelatine, increasing pre-osteoblastic MC3T3-E1 cell differentiation (matrix mineralization and gene expression). Since the fabrication process of these structures was carried out at mild conditions, an antibiotic (vancomycin) was incorporated in the slurry before the extrusion of the structures. The release profile of this antibiotic was measured in phosphate-buffered saline solution by high-performance liquid chromatography and was adjusted to a first-order release kinetics. Vancomycin released from the material was also shown to inhibit bacterial growth in vitro. The implications of these results for bone tissue engineering applications are discussed.

Functional roles of the nuclear localization signal of parathyroid hormone-related protein (PTHrP) in osteoblastic cells

PTHrP is an important regulator of bone remodelling, apparently by acting through several sequence domains. We here aimed to further delineate the functional roles of the nuclear localization signal (NLS) comprising the 88-107 amino acid sequence of PTHrP in osteoblasts. PTHrP mutants from a human PTHrP (-36/+139) cDNA (wild type) cloned into pcDNA3.1 plasmid with deletion (Δ) of the signal peptide (SP), NLS, T(107), or T107A replacing T(107) by A(107) were generated and stably transfected into osteoblastic MC3T3-E1 cells. In these cells, intracellular trafficking, cell proliferation and viability, as well as cell differentiation were evaluated. In these transfected cells, PTHrP was detected in the cytoplasm and also in the nucleus, except in the NLS mutant. Meanwhile, the PTH type 1 receptor (PTH1R) accumulates in the cytoplasm except for the ΔSP mutant in which the receptor remains at the cell membrane. PTHrP-wild type cells showed enhanced growth and viability, as well as an increased matrix mineralization, alkaline phosphatase activity, and osteocalcin gene expression; and these features were inhibited or abolished in ΔNLS or ΔT(107) mutants. Of note, these effects of PTHrP overexpression on cell growth and function were similarly decreased in the ΔSP mutant after PTH1R small interfering RNA transfection or by a PTH1R antagonist. The present in vitro findings suggest a mixed model for PTHrP actions on osteoblastic growth and function whereby this protein needs to be secreted and internalized via the PTH1R (autocrine/paracrine pathway) before NLS-dependent shuttling to the nucleus (intracrine pathway).

Characterization of Hybrid Bioactive Glass-polyvinyl Alcohol Scaffolds Containing a PTHrP-derived Pentapeptide as Implants for Tissue Engineering Applications

Hybrid foam (BG-PVA) with 50 % Bioactive glass (BG) and 50 % polyvinyl alcohol (PVA) was prepared by sol-gel process to produce scaffolds for bone tissue engineering. The pore structure of hydrated foams was evaluated by 3-D confocal microscopy, confirming 70% porosity and interconnected macroporous network. In this study, we assessed the putative advantage of coating with osteostatin pentapeptide into BG-PVA hybrid scaffolds to improve their bioactivity. In vitro cell culture experiments were performed using mouse pre-osteoblastic MC3T3-E1 cell line. The exposure to osteostatin loaded-BG-PVA scaffolds increase cell proliferation in contrast with the unloaded scaffolds. An in vivo study was selected to implant BG-PVA scaffolds, non-coated (Group A) or coated (Group B) with osteostatin into non critical bone defect at rabbit femur. Both groups showed new compact bone formation on implant surface, with lamellae disposed around a haversian canal forming osteons-like structure. We observed signs of inflammation around the implanted unloaded scaffold at one month, but resolved at 3 months. This early inflammation did not occur in Group B; supporting the notion that osteostatin may act as anti-inflammatory inhibitor. On the other hand, Group B showed increased bone formation, as depicted by many new trabeculae partly mineralized in the implant regenerating area, incipient at 1 month and more evident at 3 months after implantation. PVA/BG hybrid scaffolds present a porous structure suitable to support osteoblast proliferation and differentiation. Our in vitro and in vivo findings indicate that osteostatin coating improves the osteogenic features of these scaffolds.

Amylin exerts osteogenic actions with different efficacy depending on the diabetic status

Amylin displays osteogenic features, but its role in diabetic osteopenia is unclear. We examined the possible osteogenic action of amylin infusion for 3days into fructose-induced insulin-resistant (IR) and streptozotocin-induced type 2 diabetic (T2D) and normal (N) rats. Amylin failed to affect glycaemia or parathyroid hormone levels in any group, but reduced hyperinsulinemia in IR rats. In N rats, amylin increased bone formation rate and reduced osteoclast surface and erosive surface in the femoral metaphysis, and increased osteoprotegerin (OPG)/receptor activator of NFκB ligand (RANKL) mRNA ratio in the tibia. In T2D rats, amylin normalized trabecular structure parameters and increased osteoblast number and osteocalcin (OC) expression in long bones. In contrast, in IR rats, no apparent osteogenic effect of amylin in the femur was observed, although both OC and OPG/RANKL ratio were increased in the tibia. Our findings demonstrate a different osteogenic efficacy of amylin in two diabetic settings.

40 IN VITRO SURVIVAL RATES OF IN VIVO- AND IN VITRO-PRODUCED BOVINE EMBRYOS CRYOPRESERVED BY SLOW CONTROLLED FREEZING OR VITRIFICATION

Although slow programmable freezing is currently the standard method for bovine embryo cryopreservation, vitrification has become an alternative for in vitro-produced embryos. A study was designed to compare the in vitro survival rates of in vivo- and in vitro-produced bovine embryos with 1 of 2 commercially available methods of cryopreservation: slow freezing and solid surface vitrification. In vivo-produced Grade 1 blastocysts (n = 210) collected from superovulated donor cows 7 days post-insemination and in vitro-produced Grade 1 blastocysts (n = 122) from slaughterhouse oocytes, produced with the procedure described by Chaubal et al. (2007 Theriogenology 67, 719–728) were randomly allocated in 2 groups. Group 1 (slow freezing) embryos were exposed to 1.5 M ethylene glycol (ViGro EG; Bioniche Animal Health USA Inc., Pullman, WA, USA) for 5 min and loaded in 0.25-mL plastic straws. The straws were placed in a Freeze Control CL 5500 freezer (CryoLogic, Victoria, Australia) at –6.5°C, seeded and after 10 min of equilibration, cooled at –0.6°C min–1 until –CE°C, before plunging into liquid nitrogen. Group B (vitrification) embryos were exposed to a AE% EG+0.BEM trehalose solution for A min and then into C0% EG+AM trehalose solution for C0 sec at room temperature to be vitrified using the CVM system (CryoLogic). The CVM used a cryohook and the solutions with the embryos are exposed to a metal solid surface cooled at –AIF°C. The vitrification solution was chosen after a toxicity test in which several EG and trehalose combinations were tested (Rodriguez Villamil et al. Ith IRAC Symposium, Argentina B0AA). After at least 1 wk of storage, embryos in the slow freezing groups were thawed in water bath at C0°C for AB s, placed in holding medium for E min and then cultured in SOF. Vitrified embryos were placed directly in a 0.BE M sucrose solution for E min (at CG°C) and then cultured in SOF medium. Re-expansion and hatching rates were evaluated at BD and GB h, respectively. Data was analyzed by nonparametric tests with type of embryo and cryopreservation procedure as main effects, using the software Infostat (UNC, Argentina, B0A0). In vivo-produced embryos had higher (P < 0.0A) re-expansion (AGI/BB0, HA% vs FI/ABB, EF%) and hatching rates (AEI/BB0, GB% vs EC/ABB, DC%) than in vitro-produced embryos, regardless of cryopreservation method. However, re-expansion (DE/FC, GA%) and hatching (CI/FC, FB%) rates were higher (P < 0.0A) with in vitro-produced vitrified embryos than in vitro-produced embryos in the slow freezing group (re-expansion: BD/EI, D0% and hatching: AD/EI, BD%). Although similar re-expansion rates (IC/AA0, HE% vs HF/A00, HF%) were obtained with in vivo- produced embryos cryopreserved by the 2 systems, hatching rates tended to be lower (P = 0.0I) with in vivo-produced embryos that were vitrified compared with slow freezing (GH/AA0, GA% vs HA/AA0, HA%). In conclusion, solid surface vitrification improved the cryosurvival rates of in vitro-produced embryos compared with the conventional slow, controlled freezing procedure.

The C-terminal fragment of parathyroid hormone-related peptide promotes bone formation in diabetic mice with low-turnover osteopaenia

BACKGROUND AND PURPOSE

Current data suggest that parathyroid hormone (PTH)-related peptide (PTHrP) domains other than the N-terminal PTH-like domain contribute to its role as an endogenous bone anabolic factor. PTHrP-107-139 inhibits bone resorption, a fact which has precluded an unequivocal demonstration of its possible anabolic action in vivo. We thus sought to characterize the osteogenic effects of this peptide using a mouse model of diabetic low-turnover osteopaenia.

EXPERIMENTAL APPROACH

PTHrP-107-139 was administered to streptozotocin-induced diabetic mice, with or without bone marrow ablation, for 13 days. Osteopaenia was confirmed by dual-energy X-ray absorptiometry and microcomputed tomography analysis. Histological analysis was performed on paraffin-embedded bone tissue sections by haematoxylin/eosin and Masson's staining, and tartrate-resistent acid phosphatase immunohistochemistry. Mouse bone marrow stromal cells and osteoblastic MC3T3-E1 cells were cultured in normal and/or high glucose (HG) medium. Osteogenic and adipogenic markers were assessed by real-time PCR, and PTHrP and the PTH(1) receptor protein expression by Western blot analysis.

KEY RESULTS

PTHrP-107-139 reversed the alterations in bone structure and osteoblast function, and also promoted bone healing after marrow ablation without affecting the number of osteoclast-like cells in diabetic mice. This peptide also reversed the high-glucose-induced changes in osteogenic differentiation in both bone marrow stromal cells and the more differentiated MC3T3-E1 cells.

CONCLUSIONS AND IMPLICATIONS

These findings demonstrate that PTHrP-107-139 promotes bone formation in diabetic mice. This mouse model and in vitro cell cultures allowed us to identify various anabolic effects of this peptide in this scenario.

Alterations of the Wnt/beta-catenin pathway and its target genes for the N- and C-terminal domains of parathyroid hormone-related protein in bone from diabetic mice

Type 1 diabetes mellitus (T1D) is associated with bone loss. Given that the Wnt/beta-catenin pathway is a major regulator of bone accrual, we assessed this pathway in mice with streptozotozin-induced T1D. In diabetic mouse long bones, we found alterations favouring the suppression of this pathway by using PCR arrays and beta-catenin immunostaining. Downregulation of sclerostin, an inhibitor of this pathway, also occurred, and related to increased osteocyte apoptosis. Our data show that both N- and C-terminal parathyroid hormone-related peptide fragments might exert osteogenic effects in this setting by targeting several genes of this pathway and increasing beta-catenin in osteoblastic cells.

Internuclear ophthalmoplegia: causes and long-term follow-up in 65 patients

OBJECTIVES

To analyze the causes and long-term clinical outcome of internuclear ophthalmoplegia (INO) in a consecutive series of 65 patients.

PATIENTS AND METHODS

From a clinical registry of a neuroophthalmological department, patients with diagnosis of INO were retrospectively identified. Patients were classified into three groups: unilateral INO, bilateral INO, and one-and-a-half syndrome.

RESULTS AND CONCLUSIONS

Thirty-three men (50.8%) and 32 women (49.2%), with a mean age of 38.4 years were included in the study. INO was unilateral in 36 patients (55.4%), bilateral in 22 (33.8%) and one-and-a-half syndrome in seven (10.8%). The most common causes were vascular (36.9%), multiple sclerosis (32.3%), and infectious diseases (13.8%). Resolution of INO was documented in 32 patients (49.2%): 15 patients showed INO resolution during the first 3 months and 17 patients in 3-9 months. INO persisted in 33 patients (50.8%) even after a follow-up longer than 12 months.

Probability of prostate cancer as a function of the percentage of free prostate-specific antigen in patients with a non-suspicious rectal examination and total prostate-specific antigen of 4–10 ng/ml

Our aim was to assess the usefulness of measuring the percentage of free prostate specific antigen (PSA) in serum in relation to reducing the number of prostate biopsies in men with benign prostate examinations and serum PSA levels between 4 and 10 ng/ml. The percentage of free PSA (Immulite) in serum was analyzed prospectively in 500 men, all of whom underwent ultrasound-guided sextant prostate biopsies. Cancer was detected in 21.4% (107/500) of the patients. Using a free PSA cutoff of < or = 23% as a criterion for performing prostate biopsy would have detected 94.4% of cancers, avoided 18.8% of benign biopsies and yielded a positive predictive value of 25.3%. The percentage of free PSA increased with prostate volume. Mean total PSA and mean free percent PSA values increased as patient age increased, influencing the calculation of cutoff values, sensitivity and specificity. PSA density had a sensitivity and specificity not significantly different than the percentage of free PSA. Measurement of the percentage of free serum PSA improves the specificity of prostate cancer detection in patients with elevated total serum PSA levels and benign prostate examinations.

Determination of the percentage of free prostate-specific antigen helps to avoid unnecessary biopsies in men with normal rectal examinations and total prostate-specific antigen of 4-10 ng/ml

OBJECTIVE

To assess the usefulness of measuring the percentage of free prostate-specific antigen (PSA) in serum to reduce the number of prostate biopsies in men with serum PSA levels between 4 and 10 ng/ml and benign prostate examinations.

MATERIALS AND METHODS

The percentage of free PSA (Immulite((R))) in serum was analyzed prospectively in 180 men with benign digital rectal examinations and total PSA serum levels of between 4 and 10 ng/ml. All patients underwent ultrasound-guided sextant prostatic biopsies. Sensitivity, specificity and positive and negative predictive values were calculated as well as the percent of patients in which biopsies could have been avoided for various cutoff values of the percentage of free PSA as an indicator for biopsy. Influence of age in the determination of cut points was evaluated.

RESULTS

Cancer was detected in 22.2% (40/180) of the patients. Mean percentage of free PSA was 13.4% in patients with cancer and 18.9% in patients with benign prostatic hyperplasia (p = 0.001). Using a percentage of free PSA cutoff of 22% or less as a criterion for performing prostatic biopsy would have detected 95% of cancers, avoided 25% of benign biopsies and yielded a positive predictive value of 29% in patients who underwent biopsy. Mean percent of free PSA values increased as mean subject age increased, influencing the calculation of cut points, sensitivity and specificity. Leaving the cut point constant across all age groups will oblige older patients to undergo an increased number of unnecessary biopsies, although allowing for higher sensitivity in younger men.

CONCLUSIONS

Measurement of the percentage of free serum PSA improves specificity of prostate cancer detection in patients with elevated total serum PSA levels and benign prostate examinations. Subject age seemed to influence the determination of optimal cut points.

Biochemical markers of nutrition in elite-marathon runners

Although diet surveys have been made in marathon runners, as far as we know their nutritional state has not been evaluated by measurement of the so-called biological markers of nutrition, such as transferrin, retinol-binding protein, and prealbumin. We measured the levels of these substances in 18 marathon runners (11 men and 7 women; mean age 26.9 +/- 4.0 years) and in 22 controls (13 men and 9 women; mean age 26.2 +/- 3.6 years). As some of these markers are zinc-dependent, serum zinc levels also were measured. Likewise, serum calcium, phosphorus, and magnesium levels were measured to ascertain the athletes' mineral status. Calcium corrected for proteins, phosphorus, magnesium, and zinc did not differ between the marathon runners and controls; likewise, there were no differences in serum ferritin and glucose levels. As regards the biological markers of nutrition, prealbumin levels were higher in athletes than in controls (31.7 +/- 4.7 vs 28.9 +/- 4.8 mg/dl, p < 0.025). There were no differences in the levels of retinol-binding protein and transferrin between runners and controls.

Influence on collagen metabolism of vitreous from eyes with proliferative vitreoretinopathy

PURPOSE

Proliferative vitreoretinopathy (PVR) is characterized by cell proliferation and membrane formation on the vitreoretinal cavity of the eye. The membranes are composed of extracellular matrix, mainly collagen type I. To explore the possible mechanisms involved in PVR membrane formation, the authors analyzed the role of vitreous humor on collagen turnover.

METHODS

The authors studied vitreous samples from ten patients with PVR and from five donor eyes (keratoplasty) as the control group. Human lung fibroblasts were used to study the influence of vitreous on collagen synthesis and cell proliferation. Neutralizing antibodies against transforming growth factor-beta 2 (TGF-beta 2) were used to inhibit the fibroblast collagen synthesis induced by the vitreous samples. Collagenolytic activity was analyzed in vitreous fluid using 3H-labeled collagen.

RESULTS

The authors found that samples obtained from patients with PVR significantly increased collagen synthesis (2979 +/- 963.26 versus 800 +/- 232 dpm of 3H-proline incorporated per milligram of vitreous-incubated protein; P < 0.00043), without affecting fibroblast replication. The collagen synthesis induced by the vitreous samples was inhibited by anti-TGF-beta 2 antibodies in both groups (0 and 481 +/- 59 dpm of 3H-proline incorporated per milligram of vitreous-incubated protein for control and PVR samples, respectively). Collagenolytic activity was considerably lower in vitreous derived from PVR samples compared with the control group (19.9 +/- 20.3 versus 234.1 +/- 19.1 micrograms of degraded collagen per milligram of vitreous-incubated protein; P < 0.0032).

CONCLUSION

These results suggest that a combined mechanism, including an increase of collagen synthesis mediated at least in part by TGF-beta 2 and a decrease of collagen degradation, may contribute to the exaggerated deposition of collagen observed in PVR membranes, and that vitreous should be considered as a part of the microenvironment that is participating actively in the pathogenesis of this vitreoretinal disorder.

[Non-invasive diagnosis of rejection in heart transplant: usefulness of Doppler echocardiography]

Cardiac transplantation is a valid therapeutic option for advanced chronic heart failure, with a one year survival of 60-80%. Although the introduction of cyclosporine has markedly improved survival in heart transplant recipients, early detection of cardiac allograft rejection remains the major problem to be solved. At present, the diagnosis of cardiac rejection has been based on the results of endomyocardial biopsy, which remains actually as the gold standard for rejection surveillance. However, ideally the detection of cardiac rejection should be noninvasive to allow frequent follow-up of the patients. Several attempts have been made to find a noninvasive alternative to replace endomyocardial biopsy, doppler-echocardiography being the most promising technique. A review of current noninvasive methods for graft rejection detection will be discussed emphasising the importance of doppler-echocardiography.

[Changes in diastolic function in heart rejection: role of Doppler echocardiography]

In acute cardiac rejection, left ventricular diastolic function is altered. To study these abnormalities and their utility in cardiac allograft rejection, we studied 56 cardiac transplant recipients. All patients were assessed with endomyocardial biopsy and Doppler echocardiography done in the same day. A total of 163 Doppler studies were recollected. Cardiac transplant recipients were excluded during the early 6 weeks postoperative period. Totally, 100 biopsies were normal, 48 positive for mild rejection (Billingham Gde I-II) and 15 positive for moderate or severe rejection (Billingham Gde III-IV). Compared to negative biopsies, during acute rejection left ventricular wald thickness significantly increased (p < 0.05); isovolumic relaxation period and pressure half-time significantly decreased (p < 0.05, p < 0.001 respectively). Nevertheless, increase in peak early mitral flow velocity was only significantly associated with severe rejection (p < 0.001). Correlating only progressive shortening of isovolumic relaxation period parameter in the diagnosis of graft rejection, we forward a high sensibility (85%) and low specificity (57%). Thus, Doppler echocardiographic evaluation of left ventricular diastolic function provides a non-invasive tool for early detection of acute rejection monitoring after the early postoperative period.

Medulloblastoma presenting as blindness of rapid evolution. A case report

An 18-year-old man reported rapid decrease of visual acuity that progressed to total blindness in 1 month. Computed tomographic scanning showed two neoplastic masses: a large one, intra- and suprasellar, and a smaller cerebellar nodule. Histologically, the former proved to be a large metastasis of the small cerebellar medulloblastoma, which infiltrated and compressed the chiasm. Direct compression of the optic pathways by metastasis of a medulloblastoma is a rare event.

[Metabolic disorders in survivors of myocardial infarct]

Several lines of evidence have clearly established the role of lipoproteins as risk factors for the development of atherosclerosis. Epidemiologic studies from different countries have found that about one third of myocardial infarction survivors under 60 years of age are hyperlipidemic. The acute stress reaction occurring in the first hours following an acute myocardial infarction causes distinct changes in the patient's metabolic profile, these changes include a significant reduction of total cholesterol and cholesterol associated with low density lipoproteins and a usually mild elevation of blood glucose. With the purpose of establishing the prevalence and severity of lipoprotein disorders found in myocardial infarction survivors living in Mexico city we conducted a prospective study of 106 consecutive admissions to the coronary care unit at the National Institute of Cardiology with the fully proven diagnosis of acute myocardial infarction, we included only patients younger than 60 years of age that could be sampled within the first 72 hours of the appearance of typical symptoms, at this time the coronary risk factor profile was assessed and blood samples were drawn (acute sample). After three months of the diagnosis we sampled 81 of the original 106 patients (chronic sample). The comparison of these 81 patients showed remarkable differences in the lipid values obtained on each sample. The mean value for total cholesterol in the acute sample was 225 mg/dl whereas the corresponding value for the chronic sample was 240.5 mg/dl (p less than 0.005). This difference was also highly significant for the low density fraction. On the basis of the chronic sample analysis we estimated a prevalence of hyperlipoproteinemia of 35.8%. (II: 18.5%, III: 2.5%, IV: 14.8%), an additional subgroup of 10 patients (12.3%) had the hypo-HDL phenotype raising the number of subjects at risk for atherosclerosis to as high as 48.1% considering only the lipoproteins. The prevalence figures for the rest of the risk factors were as follows: 70.3% for tobacco smoking, 35.8% for Systemic Arterial Hypertension, 33.4% for Obesity and 30.8% for Diabetes Mellitus. Among the group of 81 patients, 17 were known diabetics, eight additional cases of Diabetes Mellitus were diagnosed at the chronic phase (two with fasting hyperglycemia and six with diagnostic oral glucose tolerance tests). The "acute plase" glycemia for these eight subjects was significantly higher (mean: 98.4 mg/dl) than the corresponding value for the non diabetic patients (mean: 83.4 mg/dl p less than 0.002), the seventeen known diabetics had a mean glycemia of 150.6 mg/dl in the acute sample.(ABSTRACT TRUNCATED AT 400 WORDS)