Screening for preclinical parenchymal lung disease in rheumatoid arthritis

OBJECTIVES

Pulmonary disease is a common extraarticular manifestation of RA associated with increased morbidity and mortality. No current strategies exist for screening this at-risk population for parenchymal lung disease, including emphysema and interstitial lung disease (ILD).

METHODS

RA patients without a diagnosis of ILD or chronic obstructive pulmonary disease underwent prospective and comprehensive clinical, laboratory, functional and radiological evaluations. High resolution CT (HRCT) scans were scored for preclinical emphysema and preclinical ILD and evaluated for other abnormalities.

RESULTS

Pulmonary imaging and/or functional abnormalities were identified in 78 (74%) of 106 subjects; 45% had preclinical parenchymal lung disease. These individuals were older with lower diffusion capacity but had similar smoking histories compared with no disease. Preclinical emphysema (36%), the most commonly detected abnormality, was associated with older age, higher anti-cyclic citrullinated peptide antibody titres and diffusion abnormalities. A significant proportion of preclinical emphysema occurred among never smokers (47%) with a predominantly panlobular pattern. Preclinical ILD (15%) was not associated with clinical, laboratory or functional measures.

CONCLUSION

We identified a high prevalence of undiagnosed preclinical parenchymal lung disease in RA driven primarily by isolated emphysema, suggesting that it may be a prevalent and previously unrecognized pulmonary manifestation of RA, even among never smokers. As clinical, laboratory and functional evaluations did not adequately identify preclinical parenchymal abnormalities, HRCT may be the most effective screening modality currently available for patients with RA.

Growth factor release from a chemically modified elastomeric poly(1,8-octanediol-co-citrate) thin film promotes angiogenesis in vivo

The ultimate success of in vivo organ formation utilizing ex vivo expanded "starter" tissues relies heavily upon the level of vascularization provided by either endogenous or artificial induction of angiogenic or vasculogenic events. To facilitate proangiogenic outcomes and promote tissue growth, an elastomeric scaffold previously shown to be instrumental in the urinary bladder regenerative process was modified to release proangiogenic growth factors. Carboxylic acid groups on poly(1,8-octanediol-co-citrate) films (POCfs) were modified with heparan sulfate creating a heparan binding POCf (HBPOCf). Release of proangiogenic growth factors vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), and insulin-like growth factor 1 (IGF-1) from HBPOCfs demonstrated an approximate threefold increase over controls during a 30-day time course in vitro. Atomic force microscopy demonstrated significant topological differences between films. Subcutaneous implantation of POCf alone, HBPOCf, POCf-VEGF, and HBPOCf-VEGF within the dorsa of nude rats yielded increased vascular growth in HBPOCf-VEGF constructs. Vessel quantification studies revealed that POCfs alone contained 41.1 ± 4.1 vessels/mm², while HBPOCf, POCf-VEGF, and HBPOCF-VEGF contained 41.7 ± 2.6, 76.3 ± 9.4, and 167.72 ± 15.3 vessels/mm², respectively. Presence of increased vessel growth was demonstrated by CD31 and vWF immunostaining in HBPOCf-VEGF implanted areas. Data demonstrate that elastomeric POCfs can be chemically modified and possess the ability to promote angiogenesis in vivo.

Urinary bladder smooth muscle regeneration utilizing bone marrow derived mesenchymal stem cell seeded elastomeric poly(1,8-octanediol-co-citrate) based thin films

Bladder regeneration studies have yielded inconclusive results possibly due to the use of unfavorable cells and primitive scaffold design. We hypothesized that human mesenchymal stem cells seeded onto poly(1,8-octanediol-co-citrate) elastomeric thin films would provide a suitable milieu for partial bladder regeneration. POCfs were created by reacting citric acid with 1,8-octanediol and seeded on opposing faces with human MSCs and urothelial cells; normal bladder smooth muscle cells and UCs, or unseeded POCfs. Partial cystectomized nude rats were augmented with the aforementioned POCfs, enveloped with omentum and sacrificed at 4 and 10 weeks. Isolated bladders were subjected to Trichrome and anti-human gamma-tubulin, calponin, caldesmon, smooth muscle gamma-actin, and elastin stainings. Mechanical testing of POCfs revealed a Young's modulus of 138 kPa with elongation 137% its initial length without permanent deformation demonstrating its high uniaxial elastic potential. Trichrome and immunofluorescent staining of MSC/UC POCf augmented bladders exhibited typical bladder architecture with muscle bundle formation and the expression and retention of bladder smooth muscle contractile proteins of human derivation. Quantitative morphometry of MSC/UC samples revealed muscle/collagen ratios approximately 1.75x greater than SMC/UC controls at 10 weeks. Data demonstrate MSC seeded POCfs support partial regeneration of bladder tissue in vivo.

Defined populations of bone marrow derived mesenchymal stem and endothelial progenitor cells for bladder regeneration

PURPOSE

Autologous sources of bone marrow mesenchymal stem cells and endothelial progenitor cells are attractive alternatives to cells currently used for bladder tissue regeneration. To evaluate the potential use of these cells we determined whether mesenchymal stem cells have contractile protein profiles and physiological functions similar to those of normal bladder smooth muscle cells, and determined the angiogenic potential of endothelial progenitor cells.

MATERIALS AND METHODS

Mesenchymal stem cells and smooth muscle cells (Lonza, Gaithersburg, Maryland) underwent proliferation and Western blot analyses. Immunofluorescence imaging was performed using antibodies against smooth muscle cell epitopes. Contractility was assessed by intracellular Ca(2+) release assays and confocal microscopy after carbachol stimulation. Endothelial progenitor cells were evaluated using a chicken chorioallantoic membrane model to determine neo-angiogenic potential.

RESULTS

Western blot and immunofluorescence data showed that mesenchymal stem cells endogenously expressed known smooth muscle cell contractile proteins at levels similar to those of smooth muscle cells. Ca(2+) release assays revealed that smooth muscle cells and mesenchymal stem cells responded to carbachol treatment with a mean +/- SD of 8.6 +/- 2.5 and 5.8 +/- 0.8 RFU, respectively, which was statistically indistinguishable. Proliferation trends of mesenchymal stem cells and control smooth muscle cells were also similar. Chorioallantoic membrane assay showed the growth of vasculature derived from endothelial progenitor cells.

CONCLUSIONS

Data demonstrate that mesenchymal stem cells and smooth muscle cells express the same contractile proteins and can function similarly in vitro. Endothelial progenitor cells also have the ability to form vasculature in an in vivo chorioallantoic membrane model. These findings provide evidence that mesenchymal stem cells and endothelial progenitor cells have characteristics that may be applicable for bladder tissue regeneration.