[Involvement of NO-dependent mechanisms of apelin action in myocardial protection against ischemia/reperfusion damage]

Apelin 12 (A-12) was synthesized by the automatic solid phase method with the use of Fmoc technology. The synthesized peptide was purified by preparative HPLC and identified by 1H-NMR spectroscopy and mass spectrometry. Acute myocardial infarction was induced by 40-min LAD occlusion followed by 60-min reperfusion in narcotized Wistar rats. A-12 was administrated at the onset of the reperfusion at doses of 0.07, 0.35 and 0.70 micromole/kg; N(G)-nitro-L-arginine methyl ester (L-NAME), a NOS inhibitor, was applied at a dose of 10 mg/kg 10 min prior to reperfusion alone or before A-12 administration (0.35 micromole/kg); saline was used in control. The indicated A-12 doses induced a transient reduction of the arterial systolic blood pressure (ASBP) to 85, 58, and 56% of the initial level, respectively, which was accompanied by its recovery by the end of reperfusion. All A-12 doses significantly limited myocardial infarct size by 26, 40 and 33%, respectively, compared to the value in control. After administration of A-12 at dose of 0.35 micromol/kg, this effect was combined with reduction of MB-creatine kinase (MB-CK) and lactate dehydrogenase (LDH) activities in plasma at the end of reperfusion by 56 and 47%, respectively, compared to the values in control. Inhibition of NO formation by L-NAME increased SABP but did not affect myocardial infarct size compared with that in control. Coadministration of L-NAME and A-12 resulted in lesser reduction of ASBP during reperfusion than injection of A-12 alone. This intervention led to an increase in infarct size by 26% with concomitant 1.8- and 1.5-times elevation of MB-CK and LDH activities, respectively, compared to the values in the A-12 group. The results indicate that NO is involved as a mediator of the effects of A-12 on the overall protection consisting in a limitation of infarct size and reduction of postischemic cardiomyocyte membrane damage. Cardioprotective mechanisms of apelin action are discussed.

Direct fabrication as a patient-targeted therapeutic in a clinical environment

A paradigm shift is taking place in orthopaedic and reconstructive surgery. This transition from using medical devices and tissue grafts towards the utilization of a tissue engineering approach combines biodegradable scaffolds with cells and/or biological molecules in order to repair and/or regenerate tissues. One of the potential benefits offered by solid freeform fabrication (SFF) technologies is the ability to create such biodegradable scaffolds with highly reproducible architecture and compositional variation across the entire scaffold due to their tightly controlled computer-driven fabrication. Many of these biologically activated materials can induce bone formation at ectopic and orthotopic sites, but they have not yet gained widespread use due to several continuing limitations, including poor mechanical properties, difficulties in intraoperative handling, lack of porosity suitable for cellular and vascular infiltration, and suboptimal degradation characteristics. In this chapter, we define scaffold properties and attempt to provide some broad criteria and constraints for scaffold design and fabrication in combination with growth factors for bone engineering applications. Lastly, we comment on the current and future developments in the field, such as the functionalization of novel composite scaffolds with combinations of growth factors designed to promote cell attachment, cell survival, vascular ingrowth, and osteoinduction.

Emerging technologies for enabling proangiogenic therapy

Ischemic disease causes a large number of deaths and significant clinical problems worldwide. Therapeutic angiogenesis, strengthened by advances in growth-factor-based therapies, is a promising solution to ischemic pathologies. Major challenges in therapeutic angiogenesis are the lack of stability of native angiogenic proteins and also providing sustained delivery of biologically active proteins at the ischemic sites. This paper will discuss various protein engineering strategies to develop stabilized proangiogenic proteins and several biomaterial technologies used to amplify the angiogenic outcome by delivering biologically active growth factors in a sustained manner.

Silica-chitosan hybrid coating on Ti for controlled release of growth factors

A hybrid material composed of a silica xerogel and chitosan was coated on Ti for the delivery of growth-factors. Fibroblast growth factor (FGF) and green fluorescence protein were incorporated into the coatings for hard tissue engineering. Silica was chosen as a coating material because of its high surface area as well as its good bioactivity. Chitosan provides mechanical stability and contributes to the control of the release rate of the growth factors. When the chitosan composition was 30% or more, the hybrid coating was stable physically and mechanically. The release of the growth-factors, observed in phosphate buffer solution at 37°C, was strongly dependent on the coating material. The hybrid coating containing FGF showed significantly improved osteoblast cell responses compared to the pure xerogel coating with FGF or the hybrid coating without FGF. These results indicate that the hybrid coating is potentially very useful in enhancing the bioactivity of metallic implants by delivering growth-factors in a controlled manner.

What should be the characteristics of the ideal bone graft substitute? Combining scaffolds with growth factors and/or stem cells

Reconstruction of large bone defects or non-unions resulting from biochemical disorders, tumour resections or complicated fractures is still a challenge for orthopaedic and trauma surgery. On the one hand, autografts harbour most features of ideal bone graft substitutes but on the other hand, they have a lot insurmountable disadvantages. An ideal bone graft substitute should be biomechanically stable, able to degrade within an appropriate time frame, exhibit osteoconductive, osteogenic and osteoinductive properties and provide a favourable environment for invading blood vessels and bone forming cells. Whilst osteoconductivity of biomaterials for bone tissue engineering strategies can be directed by their composition, surface character and internal structure, osteoinductive and osteogenic features can be provided by growth factors originally participating in fracture healing and/or multipotent mesenchymal stromal/stem cells (MSC) capable of rebuilding bone and marrow structures. In this review, aspects of the clinical application of the most commonly used growth factors for bone repair, the bone morphogenetic proteins (BMPs), and the potential use of human MSC for clinical application will be discussed.

Culture of mouse embryonic stem cells with serum but without exogenous growth factors is sufficient to generate functional hepatocyte-like cells

Mouse embryonic stem cells (mESC) have been used to study lineage specification in vitro, including towards a hepatocyte-like fate, and such investigations guided lineage differentiation protocols for human (h)ESC. We recently described a four-step protocol to induce hepatocyte-like cells from hESC which also induced hepatocyte-like cell differentiation of mouse induced pluripotent stem cells. As ESC also spontaneously generate hepatocyte-like cells, we here tested whether the growth factors and serum used in this protocol are required to commit mESC and hESC to hepatocyte-like cells. Culture of mESC from two different mouse strains in the absence of serum and growth factors did not induce primitive streak/definitive endoderm genes but induced default differentiation to neuroectoderm on day 6. Although Activin-A and Wnt3 induced primitive streak/definitive endoderm transcripts most robustly in mESC, simple addition of serum also induced these transcripts. Expression of hepatoblast genes occurred earlier when growth factors were used for mESC differentiation. However, further maturation towards functional hepatocyte-like cells was similar in mESC progeny from cultures with serum, irrespective of the addition of growth factors, and irrespective of the mouse strain. This is in contrast to hESC, where growth factors are required for specification towards functional hepatocyte-like cells. Culture of mESC with serum but without growth factors did not induce preferential differentiation towards primitive endoderm or neuroectoderm. Thus, although induction of primitive streak/definitive endoderm specific genes and proteins is more robust when mESC are exposed to a combination of serum and exogenous growth factors, ultimate generation of hepatocyte-like cells from mESC occurs equally well in the presence or absence of exogenous growth factors. The latter is in contrast to what we observed for hESC. These results suggest that differences exist between lineage specific differentiation potential of mESC and hESC, requiring optimization of different protocols for ESC from either species.

Acute injection of ASP in the third ventricle inhibits food intake and locomotor activity in rats

Acylation-stimulating protein (ASP; also known as C3adesArg) stimulates triglyceride synthesis and glucose transport via interaction with its receptor C5L2, which is expressed peripherally (adipose tissue, muscle) and centrally. Previous studies have shown that ASP-deficient mice (C3KO) and C5L2-deficient mice (C5L2KO) are hyperphagic (59 to 229% increase, P < 0.0001), which is counterbalanced by increased energy expenditure measured as oxygen consumption (Vo(2)) and a lower RQ. The aim of the present study was to evaluate ASP's effect on food intake, energy expenditure, and neuropeptide expression. Male rats were surgically implanted with intracerebroventricular (icv) cannulas directed toward the third ventricle. After a 5-h fast, rats were injected, and food intake was assessed at 0.5, 1, 2, 4, 16, 24, and 48 h, with a 5- to 7-day washout period between each injection. Acute icv injections of ASP (0.3-1,065 pmol) had a time-dependent effect on decreasing food intake by 20 to 57% (P < 0.05). Decreases were detected by 30 min (maximum 57%, P < 0.01) and at the highest dose effects extended to 48 h (19%, P < 0.05, 24- to 48-h period). Daily body weight gain was decreased by 131% over the first 24 h and 29% over the second 24 h (P < 0.05). A conditioned taste aversion test indicated that there was no malaise. Furthermore, acute ASP injection affected energy substrate usage, demonstrated by decreased Vo(2) and RQ (P < 0.05; implicating greater fatty acid usage), with a 49% decrease in total activity over 24 h (P < 0.05). ASP administration also increased anorexic neuropeptide POMC expression (44%) in the arcuate nucleus, with no change in NPY. Altogether ASP may have central in addition to peripheral effects.

Hydrodynamics-based transfection of the combination of betacellulin and neurogenic differentiation 1 DNA ameliorates hyperglycemia in mice with streptozotocin-induced diabetes

BACKGROUND

The biohazards caused by the viral delivery of pancreatic transcription factors, including neurogenic differentiation 1 (Neurod1) and Betacellulin (Btc), to the murine liver limit application of this procedure in reversing diabetes. We aimed to evaluate the feasibility of hydrodynamics-based transfection (HBT) with Neurod1 and Btc in improving hyperglycemia.

METHODS

Murine hepatocellular carcinoma (Hepa1-6) cells were transfected with the combination of Neurod1-expressing plasmid, pcDNA3.1/V5-His A (pcDNA)-Neurod1, and Btc-expressing plasmid, pcDNA3.1/V5-His A (pcDNA)-Btc. Hepatic delivery of a combination of pcDNA-Neurod1 and pcDNA-Btc (experimental group) or pcDNA (control group) to mice with streptozocin-induced diabetes was achieved by HBT. The sequential serum glucose and alanine aminotransferase (ALT) levels were assessed.

RESULTS

On day 3 after transfection, the transfection efficiencies of pcDNA-Btc and pcDNA-Neurod1 in the Hepa1-6 cells were 20% and 8%, respectively; respective values in the mouse livers were 30% and 10%. At 1 week after HBT, aside from hepatic expression of insulin, the experimental mice had a significantly lower sugar level (8-14 days after HBT, P values ranged from 0.034 to <0.001) than the control mice; the difference remained for 1 week but diminished afterward. The ALT levels and the body weight change were not different between the two groups. No mortality was noted in both groups.

CONCLUSIONS

The hypoglycemic effect of Neurod1 and Btc delivered by HBT was transient and associated with negligible complications. In studies on the short-term hypoglycemic effects of Neurod1 and Btc in vivo, HBT is a potential alternative to viral delivery of Neurod1 and Btc to the murine liver.

Effect of centrally administered apelin-13 on gastric emptying and gastrointestinal transit in mice

Apelin, as the endogenous ligand for the APJ, regulates many biological functions, including blood pressure, neuroendocrine, drinking behavior, food intake and colonic motility. The present study was designed to investigate the effect of central apelin-13 on gastric emptying and gastrointestinal transit in mice. Intracerebroventricular (i.c.v.) injection of apelin-13 (3 and 10 μg/mouse) decreased gastric emptying rate by 10.9% and 17.1%. This effect was significantly antagonized by the APJ receptor antagonist apelin-13(F13A) and the opioid receptor antagonist naloxone, respectively. However, intraperitoneal (i.p.) injection of apelin-13 (10-100 μg/mouse) did not affect gastric emptying. Apelin-13 (0.3, 1 and 3 μg/mouse, i.c.v.) inhibited gastrointestinal transit by 16.8%, 23.4% and 19.2%. Apelin-13(F13A) and naloxone could also reverse this antitransit effect induced by apelin-13. Taken together, these results suggest that i.c.v. injected apelin-13 inhibits gastric emptying and gastrointestinal transit and it seems that APJ receptor and opioid receptor might be involved in these processes.

Synergistic effects of growth factors and mesenchymal stromal cells for expansion of hematopoietic stem and progenitor cells

OBJECTIVE

The number of hematopoietic stem and progenitor cells (HPCs) per cord blood unit is limited, and this can result in delayed engraftment or graft failure. In vitro expansion of HPCs provides a perspective to overcome these limitations. Cytokines as well as mesenchymal stromal cells (MSCs) have been shown to support HPCs ex vivo expansion, but a systematic analysis of their interplay remains elusive.

MATERIALS AND METHODS

Twenty different combinations of growth factors (stem cell factor [SCF], thrombopoietin [TPO], fibroblast growth factor-1 [FGF-1], angiopoietin-like 5, and insulin-like growth factor-binding protein 2), either with or without MSC coculture were systematically compared for their ability to support HPC expansion. CD34(+) cells were stained with carboxyfluorescein diacetate N-succinimidyl ester to monitor cell division history in conjunction with immunophenotype. Colony-forming unit frequencies and hematopoietic reconstitution of nonobese diabetic severe combined immunodeficient mice were also assessed.

RESULTS

Proliferation of HPCs was stimulated by coculture with MSCs. This was further enhanced in combination with SCF, TPO, and FGF-1. Moreover, these conditions maintained expression of primitive surface markers for more than four cell divisions. Colony-forming unit-initiating cells were not expanded without stromal support, whereas an eightfold increase was reached by simultaneous cytokine-treatment and MSC coculture. Importantly, in comparison to expansion without stromal support, coculture with MSCs significantly enhanced hematopoietic chimerism in a murine transplantation model.

CONCLUSIONS

The supportive effect of MSCs on hematopoiesis can be significantly increased by addition of specific recombinant growth factors; especially in combination with SCF, TPO, and FGF-1.

Growth factor delivery-based tissue engineering: general approaches and a review of recent developments

The identification and production of recombinant morphogens and growth factors that play key roles in tissue regeneration have generated much enthusiasm and numerous clinical trials, but the results of many of these trials have been largely disappointing. Interestingly, the trials that have shown benefit all contain a common denominator, the presence of a material carrier, suggesting strongly that spatio-temporal control over the location and bioactivity of factors after introduction into the body is crucial to achieve tangible therapeutic effect. Sophisticated materials systems that regulate the biological presentation of growth factors represent an attractive new generation of therapeutic agents for the treatment of a wide variety of diseases. This review provides an overview of growth factor delivery in tissue engineering. Certain fundamental issues and design strategies relevant to the material carriers that are being actively pursued to address specific technical objectives are discussed. Recent progress highlights the importance of materials science and engineering in growth factor delivery approaches to regenerative medicine.

Nano-fibrous tissue engineering scaffolds capable of growth factor delivery

Tissue engineering aims at constructing biological substitutes to repair damaged tissues. Three-dimensional (3D) porous scaffolds are commonly utilized to define the 3D geometry of tissue engineering constructs and provide adequate pore space and surface to support cell attachment, migration, proliferation, differentiation and neo tissue genesis. Biomimetic 3D scaffolds provide synthetic microenvironments that mimic the natural regeneration microenvironments and promote tissue regeneration process. While nano-fibrous (NF) scaffolds are constructed to mimic the architecture of NF extracellular matrix, controlled-release growth factors are incorporated to modulate the regeneration process. The present article summarizes current advances in methods to fabricate NF polymer scaffolds and the technologies to incorporate controlled growth factor delivery systems into 3D scaffolds, followed by examples of accelerated regeneration when the scaffolds with growth factor releasing capacity are applied in animal models.

A two year observation of the process of applying recombinant IGF-1 to treat short stature in children with primary IGF-1 deficiency -- case reports of 3 patients

Growth deficiency is one of the most frequent causes of referral to Endocrinology Outpatient Clinic. IGF-1 (insulin-like growth factor 1) deficiency is one of the rarest causes of short stature. In 2009 in Poland a therapeutic programme was set up for children with severe primary IGF-1 deficiency. The authors present the data of three first polish patients qualified for the rhIGF-1 (recombinant human insulin-like growth factor 1) - mecasermin. The authors conclude that the treatment with rhIGF-1 significantly improves growth velocity in patients with IGF-1 deficiency. During two years of mecasermin treatment no serious side effects were noted.

Inner ear drug delivery system from the clinical point of view

CONCLUSION

Three types of inner ear drug delivery systems (DDS) that were ready to be applied in clinics were developed.

OBJECTIVES

To develop clinically applicable inner ear DDS for the treatment of inner ear disorders.

METHODS

Inner ear DDS using clinically applicable materials were developed and evaluated.

RESULTS

The systemic application of stealth-type nanoparticles encapsulating betamethasone provided superior therapeutic results for the treatment of noise-induced hearing loss compared with the systemic application of betamethasone in mice. Microparticles made of biodegradable polymer (poly (lactic/glycolic) acid, PLGA) encapsulating lidocaine were placed on the round window membrane of guinea pigs, and resulted in reasonable concentrations of lidocaine in the cochlea without serious adverse effects. The phase I/IIa clinical trial of the application of insulin-like growth factor-1 (IGF-1) in combination with gelatin hydrogel on the round window membrane was conducted, recruiting patients with acute sensorineural hearing loss after the failure of systemic application of steroids.

[Percutaneous administration of recombinant human bone morphogenetic protein-7 (rhBMP-7) after callus distraction. Two case reports]

Two cases of increased bone density after callus distraction are described following percutaneous administration of 3.5 mg recombinant bone morphogenetic protein-7 (rhBMP-7). Both patients underwent segmental resection and segmental transport for osteomyelitis of the long bones (femur and tibia) but no callus maturation occurred. After percutaneous administration of rhBMP-7 the callus density increased in both cases.

Hemodynamic effect of apelin in a canine model of acute pulmonary thromboembolism

The peptide apelin is expressed in the pulmonary vasculature and is involved in the pathogenesis of many cardiovascular diseases. It has a biphasic role in the regulation of vasomotor tone related to the vascular endothelium. In this study, we induced acute pulmonary embolism (APE) in dogs with autologous blood clots to assess the effect of apelin on pulmonary and systemic circulation in the acute phase of APE. The expression of apelin mRNA was found to be upregulated in the lung tissue in the early several hours after APE induction and decreased at 24 h. The expression of apelin protein in the pulmonary arteries did not change within 24 h after APE, but significantly increased in the bronchial epithelial cells as early as 1h and decreased at 24 h. In normal anesthetized dogs, intravenous bolus administration of apelin significantly reduced the mean arterial pressure (MAP), but did not significantly affect the mean pulmonary arterial pressure (MPAP). In the dogs with APE, apelin decreased MPAP, whereas its impact on MAP was not significantly different from that in the control group. Taken together, the level of endogenous apelin did not change significantly in the pulmonary arterial wall, whereas its expression in the bronchial epithelium was upregulated in the early stage of APE. The effect of exogenous apelin on vasomotor tone was complicated: it resulted in differential changes in the pulmonary and systemic arterial pressures under different physiological and pathological conditions.

Novel insights into human lactation as a driver of infant formula development

Progress in research on human lactation and breast milk has advanced our knowledge about the significance of breast milk for the recipient infant and the effects of various components on long-term outcomes. Recent findings have expanded our knowledge in this area. Several growth factors and cytokines are present in breast milk and their capacity to persist in the infant gut and exert their activities is likely to affect maturation of immune function, possibly affecting the development of oral tolerance. A proper balance of polyunsaturated fatty acids (n-3/n-6 ratio) may also be of significance for allergy prevention in children, emphasizing the need for the mother to achieve a balance of these fatty acids in her diet. The recent findings that specific strains of bacteria are present in breast milk and act as probiotics in the early colonization of the infant gut and that human milk oligosaccharides are specific substrates for these probiotic strains may not only affect the defense against pathogens, but also affect energy utilization and development of obesity. Previously neglected milk fat globule membranes contain several components involved in protection against infection and may be an additional arm in the multifaceted shield that breastfed infants have developed against bacterial and viral antagonists. All these findings have implications for development of improved infant formulae.

A novel technology for hematopoietic stem cell expansion using combination of nanofiber and growth factors

Hematopoietic stem cell transplantation has been applied as a standard procedure of treatment for hematological disorders like multiple myeloma and leukemia for several decades. Various sources of stem cells like bone marrow, peripheral blood and umbilical cord blood are used for the transplantation. Among these umbilical cord blood is currently preferred due to the primitiveness of the derived stem cells and minimal possibilities of graft versus host disease or development of graft induced tumors. One of the problems for these sources is the procurement of sufficient number of donor stem cells. Inadequate number of cells may lead to delayed recovery and decrease survivability of the patient. Thus to overcome the limitation of stem cell number, development of an ex-vivo expansion technology is critically important. The recent emerging technology using nanofiber in combination with growth factors has made a significant improvement to the field of regenerative medicine and a couple of patents have been filed. In this review, we will focus on factors regulating hematopoietic stem cell self-renewal and expansion emphasizing on nanofiber as a supporting matrix.

Injectable, rapid gelling and highly flexible hydrogel composites as growth factor and cell carriers

A family of injectable, rapid gelling and highly flexible hydrogel composites capable of releasing insulin-like growth factor (IGF-1) and delivering mesenchymal stromal cell (MSC) were developed. Hydrogel composites were fabricated from Type I collagen, chondroitin sulfate (CS) and a thermosensitive and degradable hydrogel copolymer based on N-isopropylacrylamide, acrylic acid, N-acryloxysuccinimide and a macromer poly(trimethylene carbonate)-hydroxyethyl methacrylate. The hydrogel copolymer was gellable at body temperature before degradation and soluble at body temperature after degradation. Hydrogel composites exhibited LCSTs around room temperature. They could easily be injected through a 26-gauge needle at 4 degrees C, and were capable of gelling within 6s at 37 degrees C to form highly flexible gels with moduli matching those of the rat and human myocardium. The hydrogel composites showed good oxygen permeability; the oxygen pressure within the hydrogel composites was similar to that in the air. The effects of collagen and CS contents on LCST, gelation time, injectability, mechanical properties and degradation properties were investigated. IGF-1 was loaded into the hydrogel composites for enhanced cell survival/growth. The released IGF-1 remained bioactive during a 2-week release period. Small fraction of CS in the hydrogel composites significantly decreased IGF-1 release rate. The release kinetics appeared to be controlled mainly by hydrogel composite water content, degradation and interaction with IGF-1. Human MSC adhesion on the hydrogel composites was comparable to that on the tissue culture plate. MSCs were encapsulated in the hydrogel composites and were found to grow inside during a 7-day culture period. IGF-1 loading significantly accelerated MSC growth. RT-PCR analysis demonstrated that MSCs maintained their multipotent differentiation potential in hydrogel composites with and without IGF-1. These injectable and rapid gelling hydrogel composites demonstrated attractive properties for serving as growth factor and cell carriers for cardiovascular tissue engineering applications.

Insulin-like growth factor I and insulin and their abuse in sport

It is believed that insulin and insulin-like growth factor I (IGF-I) are abused by professional athletes, either alone or in combination with growth hormone (GH) and anabolic steroids. The recent introduction of IGF-I to clinical practice is likely to increase its availability and abuse. Insulin and IGF-I work together with GH to control the supply of nutrients to tissues in the fasted and fed state. The actions of insulin and IGF-I that may enhance performance include increased protein anabolism and glucose uptake and storage. The detection of IGF-I and insulin abuse is challenging. There are established mass spectrometry methods for insulin analogs. The feasibility of using GH-dependent markers to detect IGF-I use is being assessed.

shRNA targeting HDGF suppressed cell growth and invasion of squamous cell lung cancer

Hepatoma-derived growth factor (HDGF), a nuclear protein with both mitogenic and angiogenic activity, has been reported to be mainly involved in tumorigenesis and the progression of non-small cell lung cancer. In this study, the HDGF expression was knocked down by specific-shRNA with lentivirus expression vector targeting HDGF in lung squamous cell carcinoma 520 cells. HDGF knocked down by shRNA suppressed the cell proliferation significantly both in vitro and in vivo as indicated by MTT, plate clone and transplanted tumor model assays. In addition, the knocked-down expression of HDGF also inhibited cell migration and invasion as shown in transwell and Boyden experiments. We concluded that HDGF acts as an oncogene participating in the pathogenesis of squamous cell lung cancer, and HDGF may be a key therapeutic target for non-small cell lung cancer.