The Protective Effects of Bevacizumab in Bleomycin-Induced Experimental Scleroderma

Current and emerging treatment options for lung cancer in patients with pre-existing connective tissue disease

An association between connective tissue disease (CTD) and lung cancer has been claimed in accumulating studies. However, the management of lung cancer with CTD is challenging because the pre-existing CTDs have proved to be significant risk factors for treatment-related toxicity, resulting in poor survival. In this review, we summarize the available information related to the treatment for lung cancer with CTD, discuss risk factors for treatment-related toxicities and management recommendations, which attempts to approach lung cancer with comorbid CTD systematically. Preliminary data show that: i) limited studies have focused on the effect of traditional therapeutic modalities, such as surgical treatment and chemotherapy; ii) with the development of the modern radiation techniques, radiotherapy would be well tolerated in this challenging clinical situation, but a cautious decision should be made for patients with CTD associated interstitial lung disease (ILD); iii) for patients with inactive CTD, immunotherapy was shown to have excellent local control with acceptable toxicity; iv) little information is available on the effects of tyrosine kinase inhibitors because of acute exacerbation (AE) of ILD risks; v) antiangiogenic therapy might be useful in preventing the progression in both lung cancer and CTD without increasing the AE-ILD risk; vi) Nintedanib would be a potentially promising novel therapy since it has recently been developed with promising results for both lung cancer and CTD-ILD. Further large-scale, randomized, controlled studies are still required to develop better therapeutic management for patients with lung cancer and pre-existing CTD.

Therapeutic molecular targets of SSc-ILD

Systemic sclerosis is a fibrosing chronic connective tissue disease of unknown etiology. A major hallmark of systemic sclerosis is the uncontrolled and persistent activation of fibroblasts, which release excessive amounts of extracellular matrix, lead to organ dysfunction, and cause high mobility and motility of patients. Systemic sclerosis–associated interstitial lung disease is one of the most common fibrotic organ manifestations in systemic sclerosis and a major cause of death. Treatment options for systemic sclerosis–associated interstitial lung disease and other fibrotic manifestations, however, remain very limited. Thus, there is a huge medical need for effective therapies that target tissue fibrosis, vascular alterations, inflammation, and autoimmune disease in systemic sclerosis–associated interstitial lung disease. In this review, we discuss data suggesting therapeutic ways to target different genes in distinct tissues/organs that contribute to the development of SSc.

Olmesartan alleviates bleomycin-mediated vascular smooth muscle cell senescence via the miR-665/SDC1 axis

Olmesartan (OMST) is a new angiotensin II receptor antagonist recently approved by the FDA to treat cardiovascular diseases. We investigated the molecular mechanisms by which OMST regulates vascular senescence. In the present study, bleomycin (BLM) was used to induce senescence in vascular smooth muscle cells (VSMCs); after which, the cells were treated with OMST. The effects of OMST on BLM-mediated cell senescence were evaluated using cell adhesion, NAD⁺/NADH, and Annevin V/PI double staining assays, as well as by immunofluorescence staining of γH2AX, Edu flow cytometry, and evaluations of senescence-associated β-gal activity. Differentially expressed microRNAs (DEMs) were identified by miRNA microarray assays, and subsequently validated by quantitative real time PCR. Bisulfite sequencing PCR (BSP) was used to detect the methylation status of the miR-665 promoter. The target genes of miR-665 were predicted and confirmed using luciferase reporter assays. We found that miR-665 was upregulated in VSMCs in response to BLM-induced cellular senescence. BSP studies revealed that CpG sites in the promoter region of the miR-665 gene underwent extensive demethylation during BLM-induced cellular senescence, and there was a concomitant up-regulation of miR-665 expression. SDC1 mRNA was identified as a direct target of miR-665. Either miR-665 overexpression or SDC1 knockdown significantly reversed the effects of OMST on BLM-induced VSMC senescence. Moreover, SDC1 overexpression partially reversed the changes that occurred in cells with BLM-induced senescence caused by miR-665 overexpression. Our findings suggest that the miR-665/SDC1 axis functions as a vital modulator of VSMC senescence, and may represent a novel biological target for treating atherosclerosis.

Metformin attenuates bleomycin-induced scleroderma by regulating the balance of Treg/Teff cells and reducing spleen germinal center formation

Scleroderma is an inflammatory autoimmune disease characterized by extensive tissue fibrosis. The imbalance of effector T (Teff) and regulatory T (Treg) cells and the production of autoantibodies contribute to the pathogenesis of this disease. Metformin (MET) has anti-inflammatory and anti-fibrotic effects, but its effect on the in vivo pathogenesis of scleroderma remains unknown. Therefore, we investigated the potential therapeutic effects of MET treatment of mice with bleomycin (BLM)-induced scleroderma. Scleroderma was induced in female C57BL mice by daily subcutaneous injections of BLM for 28 days. After each 2 h BLM injection, mice received MET (200, 100 or 50 mg/kg) or saline (control) by intraperitoneal injection. At the end of the fourth week, spleen mononuclear cells were collected for flow cytometry analysis. Skin samples were harvested for immunohistochemistry and quantification of other biological parameters.Our results showed that BLM increased dermal thickness, collagen deposition, and hydroxyproline level, and MET markedly mitigated these effects. MET also restored the Treg/Teff cell balance. Accordingly, the level of IL-17A and RORγt (related to Th17 cells) decreased, but Foxp3 (related to Treg function) increased in a dose-dependent manner. In addition, MET treatment inhibited spleen germinal center formation. These results indicate that the immunomodulatory and anti-fibrosis effects of MET on BLM-induced scleroderma are mediated by the upregulation of Treg cell differentiation, inhibition of Teff cell differentiation, and suppression of spleen germinal center formation. These results suggest that MET may be a potential therapeutic for scleroderma.

Differential roles of VEGF: Relevance to tissue fibrosis

Excessive extracellular matrix deposition and pathological vascularization are characteristics of fibrosis, which compromises the normal functioning of organs. Although whether angiogenesis can be induced and can occur in parallel with the progression of fibrosis has not been definitely determined, angiogenesis undoubtedly plays a vital role in fibrosis. Since vascular endothelial growth factor (VEGF) is one of the most effective proangiogenic factors, VEGF-targeting interventions have been a focus for the development of therapeutic strategies against fibrosis. In this review, we will summarize the current knowledge of the role of VEGF and its relevant mechanisms in fibrotic biology. We especially expect to provide a comprehensive overview of the therapeutic potential of VEGF-targeted therapy strategies to restore vascular function in the organs affected by fibrosis.

An Experimental Model of Anterior Urethral Stricture in Rabbits With Local Injections of Bleomycin

OBJECTIVE

To develop an experimental model of anterior urethral stricture in rabbits using a bleomycin (BLM) injection technique.

MATERIALS AND METHODS

Thirty adult male New Zealand rabbits were randomly divided into 4 groups. In group 1 (BLM group), BLM was injected into the urethral submucosal tissue every other day through a catheter for 6 weeks at the 3-, 6-, 9-, and 12-o'clock positions of the urethra in 12 rabbits. In group 2 (phosphate-buffered saline [PBS] group), PBS was injected instead of BLM in 6 rabbits. In group 3 (stricture control group), an 8 × 20 mm urethral defect was created in 6 rabbits. In group 4 (normal group), 6 normal rabbits were included. All rabbits in the PBS group and stricture control group, as well as 6 rabbits in the BLM group, were sacrificed at 6 weeks. The remaining 6 rabbits in the BLM group were sacrificed at 10 weeks. Urethrography was performed in all rabbits before sacrifice, and the urethra was harvested for histologic analysis.

RESULTS

All rabbits in the BLM group showed mild urethral stricture at 4 weeks and significant urethral stricture at 6 weeks, without spontaneous resolution of the stricture at 10 weeks. No urethral stricture was observed in the PBS group at 4 and 6 weeks. Histologic examination confirmed the presence of fibrosis in the BLM group without spontaneous improvement.

CONCLUSION

BLM injection can induce an experimental model of anterior urethral stricture in rabbits. This simple, highly efficient, reproducible method can be carried out in any laboratory.

The "myth" of loss of angiogenesis in systemic sclerosis: a pivotal early pathogenetic process or just a late unavoidable event?

Systemic sclerosis is considered a disease dominated by a "loss of angiogenesis", although in its early phases evidence indicates a disturbed angiogenic response only. In fact, microvascular changes are primarily due to endothelial cell injury, triggering downstream significant enlargement of the capillary in an inflammatory environment, followed by capillary rupture (microhemorrhages). Subsequent pro-angiogenic efforts lead to an aberrant angiogenesis and, eventually, to a total loss of vessel repair and regeneration (loss of angiogenesis). This clearly suggests that the pathogenetic process has a steady progression: from an early excessive pro-angiogenesis, to an aberrant microvascular regeneration, then ending with a late loss of angiogenesis. Herein, we suggest the loss of angiogenesis should not be considered as an overall "myth" characterizing systemic sclerosis but as a very late event of the vascular pathogenesis. Future research should be oriented essentially on the earlier phases dominated by excessive pro-angiogenesis and microvascular aberration.