Simvastatin promotes alveolar epithelial cell proliferation and attenuates cigarette smoke-induced emphysema in rats

The Role of Smoking in the Mechanisms of Development of Chronic Obstructive Pulmonary Disease and Atherosclerosis

Tobacco smoking is a major cause of chronic obstructive pulmonary disease (COPD) and atherosclerotic cardiovascular disease (ASCVD). These diseases share common pathogenesis and significantly influence each other's clinical presentation and prognosis. There is increasing evidence that the mechanisms underlying the comorbidity of COPD and ASCVD are complex and multifactorial. Smoking-induced systemic inflammation, impaired endothelial function and oxidative stress may contribute to the development and progression of both diseases. The components present in tobacco smoke can have adverse effects on various cellular functions, including macrophages and endothelial cells. Smoking may also affect the innate immune system, impair apoptosis, and promote oxidative stress in the respiratory and vascular systems. The purpose of this review is to discuss the importance of smoking in the mechanisms underlying the comorbid course of COPD and ASCVD.

Lipophilic statins inhibit growth and reduce invasiveness of human endometrial stromal cells

PURPOSE

To compare effects of lipid-soluble statins (simvastatin, lovastatin, atorvastatin) and water-soluble statin (pravastatin) on growth and invasiveness of human endometrial stromal (HES) cells.

METHODS

Endometrial biopsies were collected during the proliferative phase from five volunteers. HES cells were isolated and cultured in the absence or in the presence of simvastatin, lovastatin, atorvastatin, and pravastatin. Effects of statins on DNA synthesis, cell viability, activity of caspases 3/7 and invasiveness were evaluated.

RESULTS

The proliferation of HES cells was significantly decreased by simvastatin (by 47-89%), lovastatin (by 46-78%), and atorvastatin (by 21-48%) in a concentration-dependent manner. Activity of executioner caspases 3/7 was significantly increased by simvastatin (by 10-25%), lovastatin (by 19%) and atorvastatin (by 7-10%) in a concentration-dependent manner. The greatest effects were observed in response to simvastatin. Accounting for the effects of statins on cell number, the invasiveness of HES cells was significantly decreased in cells treated with simvastatin (by 49%), lovastatin (by 54%), and atorvastatin (by 53%). Pravastatin had little or no effects on any of the tested endpoints.

CONCLUSIONS

Present findings demonstrate that only lipid-soluble among tested statins were effective in inhibition of growth and invasiveness of HES cells. These findings may have clinical relevance in treatment of endometriosis.

Salvianolic acid B as an anti-emphysema agent II: In vivo reversal activities in two rat models of emphysema

Emphysema progressively destroys alveolar structures, leading to disability and death, yet remains irreversible and incurable to date. Impaired vascular endothelial growth factor (VEGF) signaling is an emerging pathogenic mechanism, thereby proposing a hypothesis that VEGF stimulation/elevation enables recovery from alveolar structural destruction and loss of emphysema. Our previous in vitro study identified that salvianolic acid B (Sal-B), a polyphenol of traditional Chinese herbal danshen, stimulated lung cell proliferation and migration, and protected against induced lung cell death, by virtue of signal transducer and activator of transcription 3 (STAT3) activation and VEGF stimulation/elevation. Thus, this study examined Sal-B for in vivo therapeutic reversal of established emphysema in two rat models. Emphysema was induced with porcine pancreatic elastase (PPE) and cigarette smoke extract (CSE), and established by day 21. Sal-B was then spray-dosed to the lung three times weekly for three weeks. Functional treadmill exercise endurance; morphological airspace enlargement and alveolar destruction; apoptosis, cell proliferation and tissue matrix proteins; phosphorylated STAT3 (pSTAT3) and VEGF expressions; neutrophil accumulation; and lipid peroxidation were determined. In both models, Sal-B at 0.2 mg/kg significantly reversed impaired exercise endurance by 80 and 64%; airspace enlargement [mean linear intercept (MLI)] by 56 and 67%; and alveolar destructive index (%DI) by 63 and 66%, respectively. Induced apoptosis activity [cleaved caspase-3] was normalized by 94 and 82%; and cell proliferation activity [proliferative cell nuclear antigen (PCNA)] was stimulated by 1.6 and 2.1-fold. In the PPE-induced model, Sal-B reduced induction of lung's matrix metalloproteinase (MMP)-9 and MMP-2 activities by 59 and 94%, respectively, and restored pSTAT3 and VEGF expressions to the healthy lung levels, while leaving neutrophil accumulation unchecked [myeloperoxidase (MPO) activity]. In the CSE-induced model, Sal-B elevated pSTAT3 and VEGF expressions both by 1.8-fold over the healthy lung levels, and normalized induced lipid peroxidation [malondialdehyde (MDA) activity] by 68%. These results provide an in vivo proof-of-concept for Sal-B as one of the first anti-emphysema agents enabling reversal of alveolar structural destruction and loss via local lung treatment by virtue of its STAT3 activation and VEGF stimulation.

Role of statins and mevalonate pathway on impaired HDAC2 activity induced by oxidative stress in human airway epithelial cells

In patients with chronic obstructive pulmonary disease (COPD) the inflammatory response is often steroid-resistant, likely since oxidative stress and cigarette smoking impair histone deacetylase 2 (HDAC2) activity. Since it has been demonstrated that statins may restore the HDAC2 activity in cultured human endothelial cells, the aim of this study was to investigate the effects of statins in reversing the steroid-resistance induced by oxidative stress. We evaluated the effects of simvastatin and dexamethasone on HDAC2 expression and activity, and the role of mevalonate and Rho/ROCK pathways in A549 cells, a human lung type II epithelial cell line stressed with H₂O₂. Our results documented that H₂O₂ significantly reduced the HDAC2 expression and activity. In H₂O₂ treated cells dexamethasone was unable to restore the activity of HDAC2, whereas simvastatin restored both the expression and the activity of this enzyme. Our data also showed that mevalonate reduced the activity of HDAC2 whereas Y27632, a Rho/ROCK inhibitor, had no effect on HDAC2 activity when co-administered with simvastatin. Our data suggest that statins could have the potential to restore corticosteroid sensitivity in A549 cells. The evidences of this study suggest that, although both mevalonate and Rho/ROCK pathways are involved in the detrimental effect elicited by oxidative stress, statins may restore the function and expression of depleted HDAC2 via modulating the mevalonate cascade, at least in A549 cells. In conclusion, the modulation of histone acetyltransferase/deacetylase activity may lead to the development of novel anti-inflammatory approaches to inflammatory lung diseases that are currently difficult to treat.

Effect of simvastatin on baboon endometriosis

Endometriosis, a common disorder affecting women of reproductive age, is characterized by ectopic growth of the endometrial tissues, altered steroid hormone response, and inflammation. Previous studies revealed that statins, selective inhibitors of the key step of mevalonate pathway, inhibit growth of endometrial stromal cells in vitro and reduce endometriotic lesions in murine models of endometriosis. This study evaluated the effects of simvastatin on the development of endometriosis in a baboon model of this disease. Sixteen baboons were randomly assigned to the treatment group (simvastatin, 20 mg daily) or to the control group. Endometriotic lesions were evaluated by laparoscopy after 3 months. The volume of red, orange-red, and white endometriotic lesions was significantly reduced by 78% in animals treated with simvastatin. The expression of a marker of proliferation, proliferating cell nuclear antigen (PCNA), was significantly reduced in animals receiving simvastatin in red lesions, white lesions, black lesions, and in adhesions. Simvastatin was also associated with an increase in the expression of estrogen receptor alpha in red lesions, and a decrease in the expression of estrogen receptor beta in black lesions, in adhesions, and in eutopic endometrium. Furthermore, simvastatin significantly reduced the expression of neopterin, a marker of inflammation, oxidative stress, and immune system activation. Collectively, the present findings indicate that the inhibition of the mevalonate pathway by simvastatin reduces the risk of developing endometriosis in the primate model of this disease by decreasing the growth of endometrial lesions, by modulating the expression of genes encoding for estrogen receptors, and by reducing inflammation.

Cigarette smoke extract-induced proliferation of normal human urothelial cells via the MAPK/AP-1 pathway

Bladder cancer (BC) is universally acknowledged as a significant public health issue, worldwide. Numerous studies have demonstrated that cigarette smoke is the primary risk factor for BC. However, the mechanism of cigarette smoke-induced BC has not been fully elucidated. Sustained epithelial cell hyperplasia has been identified as a preneoplastic lesion during the formation of BC. The aim of the present study was to investigate whether exposure to cigarette smoke extract (CSE) induced proliferation in normal human urothelial SV-HUC-1 cells. Furthermore, the role of the mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1) pathway in the CSE-induced proliferation of SV-HUC-1 cells was also investigated. The present study revealed that the expression of phosphorylated-extracellular signal regulated protein kinase (ERK)1/2, Jun N-terminal kinase (JNK) and p38 was significantly increased following exposure to CSE in SV-HUC-1 cells. Furthermore, CSE increased the expression of the proliferation markers, cyclin D1 and proliferating cell nuclear antigen. By contrast, CSE attenuated the expression of p21. In addition, the inhibitors of ERK1/2 and JNK reversed the aforementioned effects of CSE. However, p38 inhibition did not reverse CSE-induced proliferation. In conclusion, the results of the present study demonstrated that exposure to CSE induced proliferation in normal human urothelial cells. Furthermore, the results also indicated that the ERK1/2 and JNK pathways are important for the regulation of proliferation via the AP-1 proteins.