Mesoporous bioglasses enriched with bioactive agents for bone repair, with a special highlight of Maria Vallet-Regi´s contribution

Throughout her impressive scientific career, Prof. María Vallet-Regi opened various research lines aimed at designing new bioceramics, including mesoporous bioactive glasses for bone tissue engineering applica-tions. These bioactive glasses can be considered a spinoff of silica mesoporous materials because they are designed with a similar technical approach. Both materials exhibit ordered mesoporous structures with a very narrow pore size distribution that are achieved by using surfactants during their synthesis. In aqueous solutions the surfactants form mesophases behaving as directing structure agents and after being removed by calcination or extraction the mesoporous bioactive glasses are obtained. The characteristics of these ma-terials made them suitable to be enriched with various osteogenic agents, namely inorganic ions and bio-peptides as well as mesenchymal cells. In the present review, we summarize the evolution of mesoporous bioactive glasses research for bone repair, with a special highlight on the impact of Prof. Maria Val-let-Regi´s contribution to the field

A transgenic mouse model for studying the role of the parathyroid hormone-related protein system in renal injury

Parathyroid hormone- (PTH-) related protein (PTHrP) and its receptor, the PTH1 receptor (PTH1R), are widely expressed in the kidney, where PTHrP exerts a modulatory action on renal function. PTHrP is known to be upregulated in several experimental nephropathies such as acute renal failure (ARF), obstructive nephropathy (ON) as well as diabetic nephropathy (DN). In this paper, we will discuss the functional consequences of chronic PTHrP overexpression in the damaged kidney using a transgenic mouse strain overexpressing PTHrP in the renal proximal tubule. In both ARF and ON, PTHrP displays proinflammatory and profibrogenic actions including the induction of epithelia to mesenquima transition. Moreover, PTHrP participates in the mechanisms of renal hypertrophy as well as proteinuria in experimental DN. Angiotensin II (Ang II), a critical factor in the progression of renal injury, appears to be, at least in part, responsible for endogenous PTHrP upregulation in these pathophysiological settings. These findings provide novel insights into the well-known protective effects of Ang II antagonists in renal diseases, paving the way for new therapeutic approaches.The studies included in this paper were supported in part by Grants from Ministerio de Educación y Cultura of Spain (SAF2002-04356-C03-01, -02, and -03),Ministerio de Ciencia e Innovación (SAF2009- 12009-C02-01), Comunidad Autónoma de Madrid (CAM 08.6/0038.1/2000-2 and GR/SAL/0415/2004), Instituto de Salud Carlos III (RETICEF RD06/0013/1002), Spanish Society of Nephrology, Eugenio Rodríguez Pascual Foundation, and Conchita Rábago de Jiménez Díaz Foundation

Novel role of parathyroid hormone-related protein in the pathophysiology of the diabetic kidney: Evidence from experimental and human diabetic nephropathy

Parathyroid hormone-related protein (PTHrP) and its receptor type 1 (PTH1R) are extensively expressed in the kidney, where they are able to modulate renal function. Renal PTHrP is known to be overexpressed in acute renal injury. Recently, we hypothesized that PTHrP involvement in the mechanisms of renal injury might not be limited to conditions with predominant damage of the renal tubulointerstitium and might be extended to glomerular diseases, such as diabetic nephropathy (DN). In experimental DN, the overexpression of both PTHrP and the PTH1R contributes to the development of renal hypertrophy as well as proteinuria. More recent data have shown, for the first time, that PTHrP is upregulated in the kidney from patients with DN. Collectively, animal and human studies have shown that PTHrP acts as an important mediator of diabetic renal cell hypertrophy by a mechanism which involves the modulation of cell cycle regulatory proteins and TGF-β1. Furthermore, angiotensin II (Ang II), a critical factor in the progression of renal injury, appears to be responsible for PTHrP upregulation in these conditions. These findings provide novel insights into the well-known protective effects of Ang II antagonists in renal diseases, paving the way for new therapeutic approaches.N. Olea is the recipient of a Research Contract from the Comunidad Autónoma de Madrid (S-BIO-2083-2006) and the University of Alcalá. A. Izquierdo is currently Assistant Professor at the Rey Juan Carlos University, Alcorc´on, Madrid. This work was supported in part by Grants from Ministerio de Educaci´on y Cultura of Spain (SAF2002- 04356-C03-01, -02, and -03) Ministerio de Ciencia e Innovación (SAF2009-12009-C02-01), Instituto de Salud Carlos III (RETICEF RD06/0013/1002 and RD12/0043/0008 and PI12/02825), the Spanish Society of Nephrology, and the Eugenio Rodr´ıguez Pascual Foundation

Parathyroid Hormone-Related Protein Promotes Inflammation in the kidney with an Obstructed ureter

Parathyroid hormone-related protein (PTHrP) promotes fibrogenesis in the acutely damaged kidney. Considering the relation between fibrosis and inflammation, we studied transgenic mice that overexpress PTHrP in the proximal tubule. When unilateral ureteric obstruction was induced in these transgenic mice, we found that they had more renal tubulointerstitial damage, leukocyte influx, and expression of proinflammatory factors than their control littermates. Reversal of PTHrP constitutive overexpression in these transgenic mice or treatment of control mice with the PTHrP antagonist (7–34) decreased this inflammatory response. Losartan, which abolished obstruction-induced endogenous PTHrP upregulation, also decreased the latter response but less effectively in transgenic mice. The PTHrP fragment (1–36) induced nuclear factor-jB (NF-jB) activation and proinflammatory cytokine overexpression in mouse cortical tubule cells in culture as well as migration of the macrophage cell line Raw 264.7. All these effects were decreased by PTHrP (7–34) and NF-jB or extracellular signal-regulated kinase (ERK) activation inhibitors. Our findings suggest a critical role of PTHrP in the renal inflammatory process that results from ureteral obstruction and indicate that ERK-mediated NF-jB activation seems to be an important mechanism whereby PTHrP triggers renal inflammatio

Effects of bleaching on osteoclast activity and their modulation by osteostatin and fibroblast growth factor 2

Hypothesis: Dental bleaching with H2O2 is a common daily practice in dentistry to correct discoloration of anterior teeth. The aim of this study has been to determine whether this treatment of human teeth affects growth, differentiation and activity of osteoclast-like cells, as well as the putative modulatory action of osteostatin and fibroblast growth factor 2 (FGF-2). Experiments: Previously to the in vitro assays, structural, physical-chemical and morphological features of teeth after bleaching were studied. Osteoclast-like cells were cultured on human dentin disks, pre-treated or not with 38% H2O2 bleaching gel, in the presence or absence of osteostatin (100 nM) or FGF-2 (1 ng/ml). Cell proliferation and viability, intracellular content of reactive oxygen species (ROS), pro-inflammatory cytokine (IL-6 and TNF alpha) secretion and resorption activity were evaluated. Findings: Bleaching treatment failed to affect either the structural or the chemical features of both enamel and dentin, except for slight morphological changes, increased porosity in the most superficial parts (enamel), and a moderate increase in the wettability degree. In this scenario, bleaching produced an increased osteoclast-like cell proliferation but decreased cell viability and cytokine secretion, while it augmented resorption activity on dentin. The presence of either osteostatin or FGF-2 reduced the osteoclast-like cell proliferation induced by bleaching. FGF-2 enhanced ROS content, whereas osteostatin decreased ROS but increased TNF alpha secretion. The bleaching effect on resorption activity was increased by osteostatin, but this effect was less evident with FGF-2. Conclusions: These findings further confirm the deleterious effects of tooth bleaching by affecting osteoclast growth and function as well as different modulatory actions of osteostatin and FGF-2. (C) 2015 Elsevier Inc. All rights reserved

Parathyroid hormone-related protein (107-111) improves the bone regeneration potential of gelatin-glutaraldehyde biopolymer-coated hydroxyapatite

Biopolymer-coated nanocrystalline hydroxyapatite (HA) made as macroporous foams which are degradable and flexible are promising candidates as orthopaedic implants. The C-terminal (107-111) epitope of parathyroid hormone-related protein (PTHrP) exhibits osteogenic properties. The main aim of this study was to evaluate whether PTHrP (107-111) loading into gelatin-glutaraldehyde biopolymer-coated HA (HA(GIu)) scaffolds would produce an optimal biomaterial for tissue engineering applications. HA(GIu) scaffolds with and without PTHrP (107-111) were implanted into a cavitary defect performed in both distal tibial metaphysis of adult rats. Animals were sacrificed after 4 weeks for histological, microcomputerized tomography and gene expression analysis of the callus. At this time, bone healing occurred only in the presence of PTHrP (107-111)-containing HA(Giu) implant, related to an increase in bone volume/tissue volume and trabecular thickness, cortical thickness and gene expression of osteocalcin and vascular cell adhesion molecule I, but a decreased gene expression of Wnt inhibitors, SOST and dickkopf homolog 1. The autonomous osteogenic effect of the PTHrP (107-111)-loaded HA(Giu) scaffolds was confirmed in mouse and human osteoblastic cell cultures. Our findings demonstrate the advantage of loading PTHrP (107-111) into degradable HA(GIu) scaffolds for achieving an optimal biomaterial that is promising for low load bearing clinical applications. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

PTHrP-Derived Peptides Restore Bone Mass and Strength in Diabetic Mice: Additive Effect of Mechanical Loading

There is an unmet need to understand the mechanisms underlying skeletal deterioration in diabetes mellitus (DM) and to develop therapeutic approaches to treat bone fragility in diabetic patients. We demonstrate herein that mice with type 1 DM induced by streptozotocin exhibited low bone mass, inferior mechanical and material properties, increased bone resorption, decreased bone formation, increased apoptosis of osteocytes, and increased expression of the osteocyte-derived bone formation inhibitor Sost/sclerostin. Further, short treatment of diabetic mice with parathyroid hormone related protein (PTHrP)-derived peptides corrected these changes to levels undistinguishable from non-diabetic mice. In addition, diabetic mice exhibited reduced bone formation in response to mechanical stimulation, which was corrected by treatment with the PTHrP peptides, and higher prevalence of apoptotic osteocytes, which was reduced by loading or by the PTHrP peptides alone and reversed by a combination of loading and PTHrP peptide treatment. In vitro experiments demonstrated that the PTHrP peptides or mechanical stimulation by fluid flow activated the survival kinases ERKs and induced nuclear translocation of the canonical Wnt signaling mediator β-catenin, and prevented the increase in osteocytic cell apoptosis induced by high glucose. Thus, PTHrP-derived peptides cross-talk with mechanical signaling pathways to reverse skeletal deterioration induced by DM in mice. These findings suggest a crucial role of osteocytes in the harmful effects of diabetes on bone and raise the possibility of targeting these cells as a novel approach to treat skeletal deterioration in diabetes. Moreover, our study suggests the potential therapeutic efficacy of combined pharmacological and mechanical stimuli to promote bone accrual and maintenance in diabetic subjects

Osteogenic Effect of ZnO-Mesoporous Glasses loaded with Osteostatin

Mesoporous Bioactive Glasses (MBGs) are a family of bioceramics widely investigated for their putative clinical use as scaffolds for bone regeneration. Their outstanding textural properties determine high bioactivity when compared with other bioactive materials. Moreover, their great pore volumes allow these glasses to be loaded with a wide range of biomolecules to stimulate new bone formation. In this study, an MBG with composition, in mol-%, 80%SiO2–15%CaO–5%P2O5 (Blank, BL) was compared with two analogous glasses containing 4% and 5% of ZnO (4ZN and 5ZN) before and after impregnation with osteostatin, a C-terminal peptide from parathyroid hormone-related protein (PTHrP107-111). Zn2+ ions were included in the glass for their bone growth stimulator properties, whereas osteostatin was added by its osteogenic properties. Glasses were characterized, and their cytocompatibility investigated in pre-osteoblastic MC3T3-E1 cell cultures. The simultaneous additions of osteostatin and Zn2+ ions provoked enhanced MC3T3-E1 cell viability and higher differentiation capacity, compared with either raw BL or MBGs supplemented only with osteostatin or Zn2+. These in vitro results show that osteostatin enhances the osteogenic effect of Zn2+-enriched glasses, suggesting the potential of this combined approach in bone tissue engineering applications

Aplikasi Herbisida 2,4-d Dan Penoxsulam Pada Pertumbuhan Dan Hasil Tanaman Padi Sawah (Oryza Sativa L.)

Salah satu teknik budidaya untuk meningkatkan produksi tanaman padi sawah yaitu dengan mengurangi persaingan antara tanaman dengan gulma. Pengendalian dengan kimiawi merupakan salah satu cara mengurangi pertumbuhan gulma di pertanaman padi. Cara kimiawi merupakan cara yang praktis, efektif dan efisien untuk mengendalikan gulma. Penelitian ini bertujuan untuk mempelajari pengaruh dari aplikasi herbisida 2,4-D dan penoxsulam dalam meningkatkan pertumbuhan dan hasil padi sawah serta menentukan dosis aplikasi herbisida 2,4-D dan penoxsulam baik secara tunggal maupun campuran dalam mengendalikan gulma pada tanaman padi sawah. Penelitian telah dilaksanakan pada bulan Maret-Juli 2014 di Desa Campurasri, Ngawi. Penelitian menggunakan Rancangan Acak Kelompok sederhana, dengan menempatkan 11 perlakuan yaitu H1 : kontrol herbisida 2,4-D; H2 : 2,4-D 11,25 kg ha-1; H3 : 2,4-D 22,5 kg ha-1; H4 : 2,4-D 33,75 kg ha-1; H5 : kontrol herbisida penoxsulam; H6 : penoxsulam 200 ml ha-1; H7 : penoxsulam 400 ml ha-1; H8 : penoxsulam 600 ml ha-1; H9 : 2,4-D 11,25 kg ha-1 dan penoxsulam 200 ml ha-1; H10 : 2,4-D 22,5 kg ha-1 dan penoxsulam 400 ml ha-1; H11 : 2,4-D 33,75 kg ha-1 dan penoxsulam 600 ml ha-1. Hasil penelitian menunjukkan bahwa perlakuan herbisida 2,4-D 11,25 kg ha-1 dan penoxsulam 200 ml menghasilkan bobot kering total tanaman dengan peningkatan sebesar 34,62 % dibandingkan dengan kontrol. Pada produksi tanaman padi peningkatan terjadi sebesar 29,77 % pada perlakuan herbisida 2,4-D 33,75 kg ha-1 dan penoxsulam 600 ml dibandingkan dengan kontrol