Bone marrow-derived cells in renal repair

The kidney can recover after acute renal injury due to its highly effective endogenous regenerative capacity. However, under certain conditions the balance between injury and repair can get disturbed. This can ultimately lead to chronic renal failure, which is an increasing problem in the clinical setting. Therapy for renal failure has greatly improved over the years, especially by the introduction of kidney transplantation. Nevertheless, due to the shortage of donor organs and the relatively low long-term success rate after kidney transplantation, new therapeutic strategies are highly desirable. Bone marrow-derived cells (BMDC) might offer a therapeutic solution for renal failure. In this thesis we explored the differentiation choices of BMDC after acute renal injury.

House Dust Mite-Promoted Epithelial-to-Mesenchymal Transition in Human Bronchial Epithelium

The molecular basis of airway remodeling and loss of epithelial integrity in asthma is still undefined. We aimed to establish if exposure of human bronchial epithelium (16HBE cells) to asthma-related stimuli can induce epithelial-to-mesenchymal transition (EMT), a key process in tissue repair and remodeling associated with loss of intercellular contacts. We studied the effects of fibrogenic cytokine TGF-beta and protease-containing aeroallergen house dust mite (HDM) on mesenchymal and epithelial markers, cytoskeleton organization, and activation of beta-catenin-driven reporter Top-FLASH. TGF-beta alone up-regulated vimentin and fibronectin, modestly down-regulated E-cadherin, but did not affect cytokeratin. HDM alone did not affect these markers, but promoted stress fibers. Importantly, when added to TGF-beta-primed epithelium, HDM induced E-cadherin internalization, enhanced beta-catenin-dependent transcription, and down-regulated cytokeratin. Regarding the underlying mechanisms, the stimuli together induced sustained myosin light chain phosphorylation, which was crucial for E-cadherin internalization and beta-catenin-dependent transcription. Previously, we showed that HIDM signals through the epidermal growth factor receptor (EGFR). Accordingly, inhibition of EGFR prevented TGF-beta/HDM-induced mesenchymalization. TGF-beta facilitated uncoupling of EGFR from E-cadherin, its negative regulator, and prolonged EGFR signaling. Thus, we show that HIDM promotes EMT in TGF-beta-primed epithelium. Analysis of primary epithelium appears consistent with this phenotypic change. We propose that TGF-beta secretion and dysregulated EGFR signaling may increase epithelial vulnerability to allergens and trigger the induction of EMT, a hitherto unrecognized contributor to airway remodeling in asthma

Airway Epithelial Changes in Smokers but Not in Ex-Smokers with Asthma

Rationale: Smoking has detrimental effects on asthma outcome, such as increased cough, wheezing, sputum production, and frequency of asthma attacks. This results in accelerated lung function decline. The underlying pathological process of smoke-induced deterioration of asthma is unknown. Objectives: To compare bronchial inflammation and remodeling in never-smokers, ex-smokers, and current smokers with asthma. Methods: A total of 147 patients with asthma (66 never-smokers, 46 ex-smokers, and 35 current smokers) were investigated. Measurements and Main Results: Lung function, exhaled nitric oxide levels, and symptom questionnaires were assessed, and induced sputum and bronchial biopsies were obtained for determination of airway inflammation and remodeling. Smokers with asthma had lower FEV(1) and alveolar and bronchial nitric oxide levels than never-smokers. Smokers also had more goblet cells and mucus-positive epithelium, increased epithelial thickness, and a higher proliferation rate of intact and basal epithelium than ex-smokers and never-smokers. Smokers had higher numbers of mast cells and lower numbers of eosinophils than never-smokers. Ex-smokers had similar goblet cell numbers and mucus-positive epithelium, epithelial thickness, epithelial proliferation rate, and mast cell numbers as never-smokers. Conclusions: Smokers with asthma have epithelial changes that are associated with increased asthma symptoms, such as shortness of breath and phlegm production. The fact that epithelial characteristics in ex-smokers are similar to those in never-smokers suggests that the smoke-induced changes can be reversed by smoking cessation

Tubular engraftment and myofibroblast differentiation of recipient-derived cells after experimental kidney transplantation

Background. In human renal allografts, recipient-derived cells engrafted in various kidney substructures, have been detected in the long term after transplantation. Here we investigated tubular engraftment and myofibroblast differentiation of recipient-derived cells at short term after experimental kidney transplantation, during a previously described window of regeneration and possible onset of renal interstitial fibrosis. Methods. Fisher (F344, syngeneic) and Dark Agouti (DA, allogeneic) kidneys were transplanted into F344-hPAP transgenic recipient rats, which allowed tracing of recipient-derived cells in nontransgenic donor kidneys. We evaluated tubular engraftment and myofibroblast differentiation of recipient-derived cells on day 14 after kidney transplantation. Results. Kidney transplantation resulted in tubular engraftment of recipient- derived cells. After allogeneic kidney transplantation, 9.7% of tubular cross-sections contained at least one recipient- derived cell, which represented a significant increase in comparison to syngeneic transplantation (4.0%, P <0.05). Moreover, recipient-derived myofibroblasts were present in the renal interstitium of the transplanted kidney. These cells contributed 39% of the total interstitial myofibroblast population in allografts, which was comparable to the syngeneic situation (28%, P=0.25). Conclusions. In a defined early window of regeneration and possible onset of renal interstitial fibrosis after kidney transplantation, rejection-associated injury, superimposed on ischemic damage, increases tubular engraftment of recipient-derived cells, although it does not affect their relative contribution to the renal interstitial myofibroblast population

Clinical control of asthma associates with measures of airway inflammation

<p>Background Control of asthma is the goal of asthma management worldwide. The Global Initiative for Asthma defined control by a composite measure of clinical findings and future risk but without using markers of airway inflammation, the hallmark of asthma. We investigated whether clinical asthma control reflects eosinophilic inflammation in a broad population.</p><p>Methods Control of asthma was assessed over a period of 4 weeks in 111 patients with asthma: 22 totally controlled, 47 well controlled and 42 uncontrolled. Lung function, quality of life, airway hyperresponsiveness to AMP, sputum and blood eosinophils, exhaled nitric oxide (NO) and bronchial biopsies were obtained.</p><p>Results The 69 subjects with controlled asthma (totally and well controlled combined) had lower median blood eosinophil numbers, slope of AMP hyperresponsiveness, and alveolar NO levels than the 42 subjects with uncontrolled asthma: 0.18 (range 0.01-0.54) versus 0.22 (0.06-1.16)x10(9)/litre (p</p><p>Conclusions The level of asthma control, based on a composite measure of clinical findings, is associated with inflammatory markers, particularly eosinophilic inflammation, with little difference between totally controlled and well controlled asthma.</p>

Persisting Remodeling and Less Airway Wall Eosinophil Activation in Complete Remission of Asthma

Rationale Individuals with asthma may outgrow symptoms despite not using treatment, whereas others reach complete remission (CoR) with absence of airway obstruction and bronchial hyper-responsiveness. It is uncertain whether this associates with remission of all inflammatory and remodeling asthma features. Objectives: To compare the pathologic phenotype of individuals with asthma with CoR and clinical remission (ClinR) and those with active asthma, with and without the use of inhaled corticosteroids (ICS). Methods: We investigated 165 individuals known with active asthma, on reexamination having CoR (n = 18), ClinR (n = 44), and current asthma (CuA, n = 103, 64 with and 39 without ICS). Measurements Main Results: Inflammatory cells were measured in blood, induced sputum, and bronchial biopsies; histamine and ECP in sputum; and eosinophilic peroxidase (EPX) immunopositivity and remodeling (epithelial changes, E-cadherin expression, basement membrane [BM] thickening, collagen deposition) in bronchial biopsies. Median (range) blood eosinophils from CoR were significantly lower than those from CuA (0.10 [0.04-0.24] vs. 0.18 [0.02-1.16] x 10(9)/L). Bronchial EPX immunopositivity was lower in CoR than in both ClinR and CuA (67 [0.5-462] vs. 95 [8-5329] and 172 [6-5313] pixels). Other inflammatory findings were comparable. BM thickness was lowest in CuA, caused by lower BM thickness in those using ICS (CoR, 6.3 [4.7-8.4]; ClinR, 6.5 [3.8-11.7]; CuA, 5.7 [2.8-12.6]; and ICS using CuA, 5.3 [2.8-8.2] mu m). Conclusions: CoR is still accompanied by airway abnormalities because BM thickness is similar in individuals with asthma with CoR, ClinR, and CuA without ICS. Airway eosinophilic activation best differentiates these three groups, signifying their importance in the clinical expression and severity of bronchial hyper-responsiveness in asthma

Bone marrow-derived myofibroblasts contribute to the renal interstitial myofibroblast population and produce procollagen I after ischemia/reperfusion in rats

Bone marrow-derived cells (BMDC) have been proposed to exert beneficial effects after renal ischemia/reperfusion injury (IRI) by engraftment in the tubular epithelium. However, BMDC can give rise to myofibroblasts and may contribute to fibrosis. BMDC contribution to the renal interstitial myofibroblast population in relation to fibrotic changes after IRI in rats was investigated. A model of unilateral renal IRI (45 min of ischemia) was used in F344 rats that were reconstituted with R26-human placental alkaline phosphatase transgenic BM to quantify BMDC contribution to the renal interstitial myofibroblast population over time. After IRI, transient increases in collagen III transcription and interstitial protein deposition were observed, peaking on days 7 and 28, respectively. Interstitial infiltrates of BMDC and myofibroblasts reached a maximum on day 7 and gradually decreased afterward. Over time, an average of 32% of all interstitial a-smooth muscle actin-positive myofibroblasts coexpressed R26-human placental alkaline phosphatase and, therefore, were derived from the BM. BMD myofibroblasts produced procollagen I protein and therefore were functional. The postischemic kidney environment was profibrotic, as demonstrated by increased transcription of TGF-beta and decreased transcription of bone morphogenic protein-7. TGF-beta protein was present predominantly in interstitial myofibroblasts but not in BMD myofibroblasts. In conclusion, functional BMD myofibroblasts infiltrate in the postischemic renal interstitium and are involved in extracellular matrix production