Efficient autocrine and paracrine signaling explain the osteogenic superiority of transgenic BMP-2 over rhBMP-2.

Bone morphogenetic protein-2 (BMP-2) is an osteogenic protein used clinically to enhance bone healing. However, it must be applied in very high doses, causing adverse side effects and increasing costs while providing only incremental benefit. Preclinical models of bone healing using gene transfer to deliver BMP-2 suggest that transgenic BMP-2 is much more osteogenic than rhBMP-2.

Segmental defect healing in the presence or absence of recombinant human BMP2: Novel insights from a rat model.

This study defined and compared the course of native, impaired and growth factor-stimulated bone regeneration in a rat femoral defect model. A mid-diaphyseal defect with rigid internal fixation was surgically created in the right femur of male Fischer rats and serially analyzed over 36 weeks. Native bone regeneration was modeled using a sub-critical, 1 mm size defect, which healed uneventfully.

IL-1Ra gene transfer potentiates BMP2-mediated bone healing by redirecting osteogenesis toward endochondral ossification.

An estimated 100,000 patients each year in the United States suffer severe disability from bone defects that fail to heal, a condition where bone-regenerative therapies could provide substantial clinical benefits. Although recombinant human bone morphogenetic protein-2 (rhBMP2) is an osteogenic growth factor that is clinically approved for this purpose, it is only effective when used at exceedingly high doses that incur substantial costs, induce severe inflammation, produce adverse side effects, and form morphologically abnormal bone. Using a validated rat femoral segmental defect model, we show that bone formed in response to clinically relevant doses of rhBMP2 is accompanied by elevated expression of interleukin-1 (IL-1).

Enthesis Healing Is Dependent on Scaffold Interphase Morphology-Results from a Rodent Patellar Model.

The use of multiphasic scaffolds to treat injured tendon-to-bone entheses has shown promising results in vitro. Here, we used two versions of a biphasic silk fibroin scaffold to treat an enthesis defect created in a rat patellar model in vivo. One version presented a mixed transition between the bony and the tendon end of the construct (S-MT) while this transition was abrupt in the second version (S-AT).

Efficient healing of large osseous segmental defects using optimized chemically modified messenger RNA encoding BMP-2.

Large segmental osseous defects heal poorly. Recombinant, human bone morphogenetic protein-2 (rhBMP-2) is used clinically to promote bone healing, but it is applied at very high doses that cause adverse side effects and raise costs while providing only incremental benefit. We describe a previously unexplored, alternative approach to bone regeneration using chemically modified messenger RNA (cmRNA).

Picrosirius Red Staining: Revisiting Its Application to the Qualitative and Quantitative Assessment of Collagen Type I and Type III in Tendon.

Collagen has a major role in the structural organization of tendons. Picrosirius red (PSR) staining viewed under polarized light microscopy is the standard method to evaluate the organization of collagen fibers in tissues. It is also used to distinguish between type I and type III collagen in tissue sections.

An Improved, Chemically Modified RNA Encoding BMP-2 Enhances Osteogenesis In Vitro and In Vivo.

The use of chemically modified RNA (cmRNA) with increased stability using translation initiator of short untranslated regions (TISU) offers the prospect of finally allowing us to unlock the potent osteogenic properties of BMP-2 in a clinically expedient manner. As noted, delivery of recombinant BMP-2 protein has had modest clinical efficacy, whereas gene delivery is effective but very difficult to translate into human clinical use. This study shows the great potential of cmRNA encoding BMP-2 with TISU in a long-bone critical-sized rat model.

A stimulatory thyrotropin receptor antibody (M22) and thyrotropin increase interleukin-6 expression and secretion in Graves' orbital preadipocyte fibroblasts.

Background: Patients with Graves' ophthalmopathy (GO) have circulating autoantibodies directed against the thyrotropin receptor (TSHR) and elevated levels of the proinflammatory cytokine interleukin-6 (IL-6) in both serum and orbital tissues. We hypothesized that these autoantibodies might increase IL-6 expression and secretion in preadipocyte fibroblasts and adipocytes from patients with GO, and thus directly impact the clinical activity of the disease.

Methods: IL-6 mRNA levels were measured in cultures of GO orbital preadipocytes (n = 3) treated during adipocyte differentiation with a monoclonal stimulatory TSHR antibody (M22; 10 ng/mL), IL-6 (1 ng/mL), or TSH (10 U/L).

Eosinophil ribonucleases and their cutaneous lesion-forming activity.

Eosinophil granule proteins are deposited in cutaneous lesions in many human diseases, but how these proteins contribute to pathophysiology is obscure. We injected eosinophil cationic protein (ECP or RNase 3), eosinophil-derived neurotoxin (EDN or RNase 2), eosinophil peroxidase (EPO), and major basic protein-1 (MBP1) intradermally into guinea pig and rabbit skin. ECP and EDN each induced distinct skin lesions at >or=2.

Evidence for enhanced Thy-1 (CD90) expression in orbital fibroblasts of patients with Graves' ophthalmopathy.

Background: Thy-1 is a surface protein that defines functionally distinct subpopulations of fibroblasts, with those lacking the antigen being capable of adipogenesis. Because increased fat cell development is a hallmark of the orbit in Graves' ophthalmopathy (GO), we wished to compare baseline Thy-1 expression in orbital fibroblasts from GO patients and normal individuals, and determine whether levels of the protein might be impacted by adipogenesis following peroxisome proliferator activator-gamma ligation.

Methods: Orbital adipose/connective tissue specimens were obtained from euthyroid patients undergoing orbital decompression surgery for severe GO (n = 9) and from normal individuals (n = 9).

Thyroid transcription factor-1 in orbital adipose tissues: potential role in orbital thyrotropin receptor expression.

Thyroid transcription factor-1 (TTF-1) is required for maximal expression of thyrotropin receptor (TSHR) in the thyroid. Extrathyroidal TSHR expression is detectable in normal orbital adipose tissues, with increased levels found in orbital tissues from patients with Graves' ophthalmopathy (GO), and in orbital preadipocyte cultures following differentiation. In order to determine whether TTF-1 might be involved in orbital TSHR expression, we used quantitative real-time polymerase chain reaction (PCR) to assess relative expression of this and other thyroid-associated transcription factors (TTF-2 and Pax-8) in GO orbital tissue specimens (n = 28) and cultures (n = 3), and in normal orbital tissues (n = 19) and cultures (n = 3).

Gene expression profiling of orbital adipose tissue from patients with Graves' ophthalmopathy: a potential role for secreted frizzled-related protein-1 in orbital adipogenesis.

Context: The signs and symptoms of Graves' ophthalmopathy (GO) result from inflammation and increased volume of the orbital adipose tissues and extraocular muscles.

Objective: Our objective was to identify differentially regulated genes that may be involved in stimulating the orbital adipose tissue expansion seen in GO.

Design: Gene expression profiling was used to compare genes expressed in orbital adipose tissues from GO patients and normal individuals.

Evidence for enhanced adipogenesis in the orbits of patients with Graves' ophthalmopathy.

The signs and symptoms of Graves' ophthalmopathy (GO) result from increased volume of the orbital contents, including adipose, connective, and extraocular muscle tissues. We wanted to determine whether the expanded adipose tissue volume might be in part attributable to de novo adipogenesis. We measured levels of mRNA encoding leptin, adiponectin, peroxisome proliferator-activated receptor gamma (PPAR gamma), preadipocyte factor-1, and TSH receptor (TSHr) genes in orbital adipose tissues from GO patients (n = 22) and normal individuals (n = 18) and in orbital preadipocyte cultures derived from GO patients (n = 6) and normal subjects (n = 3) using quantitative real-time RT PCR.