Repairing damaged lungs using regenerative therapy

There is an urgent need for better treatment of lung diseases that are a major cause of morbidity and mortality worldwide. This urgency is illustrated by the current COVID-19 health crisis. Moderate-to-extensive lung injury characterizes several lung diseases, and not only therapies that reduce such lung injury are needed but also those that regenerate lung tissue and repair existing lung injury. At present, such therapies are not available, but as a result of a rapid increase in our understanding of lung development and repair, lung regenerative therapies are on the horizon. Here, we discuss existing targets for treatment, as well as novel strategies for development of pharmacological and cell therapy-based regenerative treatment for a variety of lung diseases and clinical studies. We discuss how both patient-relevant in vitro disease models using innovative culture techniques and other advanced new technologies aid in the development of pulmonary regenerative medicine

The effect of PPE-induced emphysema and chronic LPS-induced pulmonary inflammation on atherosclerosis development in APOE*3-LEIDEN mice.

BackgroundChronic obstructive pulmonary disease (COPD) is characterized by pulmonary inflammation, airways obstruction and emphysema, and is a risk factor for cardiovascular disease (CVD). However, the contribution of these individual COPD components to this increased risk is unknown. Therefore, the aim of this study was to determine the contribution of emphysema in the presence or absence of pulmonary inflammation to the increased risk of CVD, using a mouse model for atherosclerosis. Because smoke is a known risk factor for both COPD and CVD, emphysema was induced by intratracheal instillation of porcine pancreatic elastase (PPE).MethodsHyperlipidemic APOE*3-Leiden mice were intratracheally instilled with vehicle, 15 or 30 µg PPE and after 4 weeks, mice received a Western-type diet (WTD). To study the effect of emphysema combined with pulmonary inflammation on atherosclerosis, mice received 30 µg PPE and during WTD feeding, mice were intranasally instilled with vehicle or low-dose lipopolysaccharide (LPS; 1 µg/mouse, twice weekly). After 20 weeks WTD, mice were sacrificed and emphysema, pulmonary inflammation and atherosclerosis were analysed.ResultsIntratracheal PPE administration resulted in a dose-dependent increase in emphysema, whereas atherosclerotic lesion area was not affected by PPE treatment. Additional low-dose intranasal LPS administration induced a low-grade systemic IL-6 response, as compared to vehicle. Combining intratracheal PPE with intranasal LPS instillation significantly increased the number of pulmonary macrophages and neutrophils. Plasma lipids during the study were not different. LPS instillation caused a limited, but significant increase in the atherosclerotic lesion area. This increase was not further enhanced by PPE.ConclusionThis study shows for the first time that PPE-induced emphysema both in the presence and absence of pulmonary inflammation does not affect atherosclerotic lesion development

Acute and chronic effects of treatment with mesenchymal stromal cells on LPS-induced pulmonary inflammation, emphysema and atherosclerosis development.

COPD is a pulmonary disorder often accompanied by cardiovascular disease (CVD), and current treatment of this comorbidity is suboptimal. Systemic inflammation in COPD triggered by smoke and microbial exposure is suggested to link COPD and CVD. Mesenchymal stromal cells (MSC) possess anti-inflammatory capacities and MSC treatment is considered an attractive treatment option for various chronic inflammatory diseases. Therefore, we investigated the immunomodulatory properties of MSC in an acute and chronic model of lipopolysaccharide (LPS)-induced inflammation, emphysema and atherosclerosis development in APOE*3-Leiden (E3L) mice.Hyperlipidemic E3L mice were intranasally instilled with 10 μg LPS or vehicle twice in an acute 4-day study, or twice weekly during 20 weeks Western-type diet feeding in a chronic study. Mice received 0.5x106 MSC or vehicle intravenously twice after the first LPS instillation (acute study) or in week 14, 16, 18 and 20 (chronic study). Inflammatory parameters were measured in bronchoalveolar lavage (BAL) and lung tissue. Emphysema, pulmonary inflammation and atherosclerosis were assessed in the chronic study.In the acute study, intranasal LPS administration induced a marked systemic IL-6 response on day 3, which was inhibited after MSC treatment. Furthermore, MSC treatment reduced LPS-induced total cell count in BAL due to reduced neutrophil numbers. In the chronic study, LPS increased emphysema but did not aggravate atherosclerosis. Emphysema and atherosclerosis development were unaffected after MSC treatment.These data show that MSC inhibit LPS-induced pulmonary and systemic inflammation in the acute study, whereas MSC treatment had no effect on inflammation, emphysema and atherosclerosis development in the chronic study

Splenic autonomic denervation increases inflammatory status but does not aggravate atherosclerotic lesion development

The brain plays a prominent role in the regulation of inflammation. Immune cells are under control of the so-called cholinergic anti-inflammatory reflex, mainly acting via autonomic innervation of the spleen. Activation of this reflex inhibits the secretion of proinflammatory cytokines and may reduce the development of atherosclerosis. Therefore, the aim of this study was to evaluate the effects of selective parasympathetic (Px) and sympathetic (Sx) denervation of the spleen on inflammatory status and atherosclerotic lesion development. Female APOE*3-Leiden.CETP mice, a well-established model for human-like lipid metabolism and atherosclerosis, were fed a cholesterol-containing Western-type diet for 4 wk after which they were subdivided into three groups receiving either splenic Px, splenic Sx, or sham surgery. The mice were subsequently challenged with the same diet for an additional 15 wk. Selective Px increased leukocyte counts (i.e., dendritic cells, B cells, and T cells) in the spleen and increased gene expression of proinflammatory cytokines in the liver and peritoneal leukocytes compared with Sx and sham surgery. Both Px and Sx increased circulating proinflammatory cytokines IL-1β and IL-6. However, the increased proinflammatory status in denervated mice did not affect atherosclerotic lesion size or lesion composition. Predominantly selective Px of the spleen enhances the inflammatory status, which, however, does not aggravate diet-induced atherosclerotic lesion developmen

Groups and groups sizes.

<p>Groups and groups sizes.</p

PPE-induced emphysema combined with chronic low-grade LPS-induced pulmonary inflammation does not affect atherosclerosis development.

<p>After 20 weeks of WTD feeding, mice were sacrificed and the total atherosclerotic lesion area (A) and lesion severity (B) were assessed. Furthermore, the number of monocytes adhering to the vessel wall, (C) macrophage (D), smooth muscle cell (E), collagen content (F) of the atherosclerotic lesions and collagen type I+III of Sirius red-positive area were measured. Significant effects detected by two-way ANOVA analysis are shown as p-value in textboxes above the figure. Values are presented as means ± SEM; n = 10–15; *p<0.05, **p<0.01, ***p<0.001.</p

Intratracheal PPE instillation dose-dependently increases alveolar destruction, without affecting pulmonary inflammation.

<p>E3L mice were intratracheally instilled with vehicle, 15 or 30 µg PPE and sacrificed after 24 weeks. Mean linear intercept (B) and air/tissue ratio (C) were determined on sections of the lungs (A). Furthermore, right ventricular (RV) (D) and left ventricular (LV) wall thickness was determined and the ratio was calculated (E). The number of MAC3-positive macrophages (F) and MPO-positive neutrophils (G) in the lung was determined immunohistochemically. Values in B+C are represented as the mean; values in D-G are presented as means ± SEM; n = 12–15; *p<0.05, **p<0.01, ***p<0.001.</p

PPE-induced emphysema combined with low-dose LPS administration induces chronic low-grade pulmonary inflammation, without affecting emphysema.

<p>After intratracheal instillation of vehicle or PPE (30 µg/mouse) in <i>E3L</i> mice, low-dose intranasal LPS (1 µg/mouse) or vehicle was administered during 20 weeks WTD feeding. Total respiratory amplitude was analyzed at 8 and 18 weeks (C and D) after PPE. After sacrifice, mean linear intercept (A) and air/tissue ratio (B) were determined and inflammatory cell influx was determined by immunohistochemical staining of macrophages with F4/80 (E) and neutrophils with MPO (F). Significant effects detected by two-way ANOVA analysis are shown as p-value in textboxes above the figure. Values are presented as means ± SEM; n = 10–15; *p<0.05, **p<0.01, ***p<0.001.</p

PPE-induced emphysema does not affect atherosclerosis lesion area.

<p>During the study, blood was drawn to assess plasma cholesterol levels (A). After 20 weeks of WTD feeding mice were sacrificed, hearts were isolated and atherosclerotic lesion area (B) was determined in the aortic root area (representative pictures are shown in C). Also, the number of monocytes adhering to the vessel wall (D) and macrophage- (E), smooth muscle cell- (F) and collagen (G) content of the atherosclerotic lesions were measured. Values are presented as means ± SEM; n = 12–15; *p<0.05.</p