Platelet‐derived growth factor‐A and its receptor, platelet‐derived growth factor receptor‐alpha (PDGF‐Rα), are required for formation of the secondary pulmonary alveolar septa in mice. However, it remains unclear how these molecules direct the secondary septation process. We have examined the abundance, location, and the accumulation of alpha‐smooth muscle actin (αSMA), neutral lipid droplets, and elastin in the proximity of PDGF‐Rα‐expressing alveolar cells during postnatal days 4 through 12 in the mouse. PDGF‐Rα‐expressing cells preferentially have characteristics of myofibroblasts and were more likely to contain αSMA than are alveolar cells that do not express PDGF‐Rα. PDGF‐Rα expressing cells were preferentially located in the alveolar entry ring (AER) where αSMA and elastic fibers accumulate. In contrast, PDGF‐Rα expression inversely correlated with neutral lipid accumulation, which was more prominent at the alveolar base, distant from the AER. PDGF‐Rα‐expressing alveolar cells accumulate in the AER where they may promote mechanical stability during respiration. In addition to defining how alveolar septa form, these findings may have implications for the treatment of diseases which involve alveolar effacement such as emphysema and pulmonary fibrosis. Anat Rec, 2008. © 2008 Wiley‐Liss, Inc.

Background: Multiple sclerosis is an autoimmune disease influenced by environmental factors. Objectives: The feasibility of a multimodal intervention and its effect on perceived fatigue in patients with secondary progressive multiple sclerosis were assessed. Design/setting: This was a single-arm, open-label intervention study in an outpatient setting. Interventions: A multimodal intervention including a modified paleolithic diet with supplements, stretching, strengthening exercises with electrical stimulation of trunk and lower limb muscles, meditation, and massage was used. Outcome measures: Adherence to each component of the intervention was calculated using daily logs. Sideeffects were assessed from a monthly questionnaire and blood analyses. Fatigue was assessed using the Fatigue Severity Scale (FSS). Data were collected at baseline and months 1, 2, 3, 6, 9, and 12. Results: Ten (10) of 13 subjects who were enrolled in a 2-week run-in phase were eligible to continue in the 12-month main study. Of those 10 subjects, 8 completed the study and 6 subjects fully adhered to the study intervention for 12 months. Over a 12-month period, average adherence to diet exceeded 90% of days, and to exercise/muscle stimulation exceeded 75% of days. Nutritional supplements intake varied among and within subjects. Group daily average duration of meditation was 13.3 minutes and of massage was 7.2 minutes. No adverse side-effects were reported. Group average FSS scores decreased from 5.7 at baseline to 3.32 ( p = 0.0008) at 12 months. Conclusions: In this small, uncontrolled pilot study, there was a significant improvement in fatigue in those who completed the study. Given the small sample size and completer rate, further evaluation of this multimodal therapy is warranted.

Vitamin D is classically recognized for its role in calcium homeostasis and skeletal metabolism. Over the last few decades, vitamin D deficiency has increased in prevalence in adults and children. Potential extraskeletal effects of vitamin D have been under investigation for several diseases. Several cross-sectional studies have associated lower vitamin D status with decreased lung function. This finding has prompted investigators to examine the association of vitamin D deficiency with several chronic lung diseases. One major focus has been the link between maternal vitamin D status and childhood asthma. Vitamin D deficiency has also been associated with increased risk of respiratory infection from influenza A and Mycobacterium tuberculosis. Other chronic respiratory diseases associated with vitamin D deficiency include cystic fibrosis, interstitial lung disease, and chronic obstructive pulmonary disease. This review will examine the current clinical literature and potential mechanisms of vitamin D in various pulmonary diseases.

Patients with cystic fibrosis (CF) suffer from chronic lung infection and inflammation leading to respiratory failure. Vitamin D deficiency is common in patients with CF, and correction of vitamin D deficiency may improve innate immunity and reduce inflammation in patients with CF. We conducted a double-blinded, placebo-controlled, randomized clinical trial of high-dose vitamin D to assess the impact of vitamin D therapy on antimicrobial peptide concentrations and markers of inflammation. We randomized 30 adults with CF hospitalized with a pulmonary exacerbation to 250 000 IU of cholecalciferol or placebo, and evaluated changes in plasma concentrations of inflammatory markers and the antimicrobial peptide LL-37 at baseline and 12 weeks post intervention. In the vitamin D group, there was a 50.4% reduction in tumor necrosis factor-α (TNF-α) at 12 weeks (P<0.01), and there was a trend for a 64.5% reduction in interleukin-6 (IL-6) (P = 0.09). There were no significant changes in IL-1β, IL-8, IL-10, IL-18BP and NGAL (neutrophil gelatinase-associated lipocalin). We conclude that a large bolus dose of vitamin D is associated with reductions in two inflammatory cytokines, IL-6 and TNF-α. This study supports the concept that vitamin D may help regulate inflammation in CF, and that further research is needed to elucidate the potential mechanisms involved and the impact on clinical outcomes.

BackgroundPlatelet-derived growth factor A (PDGF-A) signals solely through PDGF-Rα, and is required for fibroblast proliferation and transdifferentiation (fibroblast to myofibroblast conversion) during alveolar development, because pdgfa-null mice lack both myofibroblasts and alveoli. However, these PDGF-A-mediated mechanisms remain incompletely defined. At postnatal days 4 and 12 (P4 and P12), using mouse lung fibroblasts, we examined (a) how PDGF-Rα correlates with ki67 (proliferation marker) or alpha-smooth muscle actin (αSMA, myofibroblast marker) expression, and (b) whether PDGF-A directly affects αSMA or modifies stimulation by transforming growth factor beta (TGFβ).MethodsUsing flow cytometry we examined PDGF-Rα, αSMA and Ki67 in mice which express green fluorescent protein (GFP) as a marker for PDGF-Rα expression. Using real-time RT-PCR we quantified αSMA mRNA in cultured Mlg neonatal mouse lung fibroblasts after treatment with PDGF-A, and/or TGFβ.ResultsThe intensity of GFP-fluorescence enabled us to distinguish three groups of fibroblasts which exhibited absent, lower, or higher levels of PDGF-Rα. At P4, more of the higher than lower PDGF-Rα + fibroblasts contained Ki67 (Ki67+), and Ki67+ fibroblasts predominated in the αSMA + but not the αSMA- population. By P12, Ki67+ fibroblasts comprised a minority in both the PDGF-Rα + and αSMA+ populations. At P4, most Ki67+ fibroblasts were PDGF-Rα + and αSMA- whereas at P12, most Ki67+ fibroblasts were PDGF-Rα- and αSMA-. More of the PDGF-Rα + than - fibroblasts contained αSMA at both P4 and P12. In the lung, proximate αSMA was more abundant around nuclei in cells expressing high than low levels of PDGF-Rα at both P4 and P12. Nuclear SMAD 2/3 declined from P4 to P12 in PDGF-Rα-, but not in PDGF-Rα + cells. In Mlg fibroblasts, αSMA mRNA increased after exposure to TGFβ, but declined after treatment with PDGF-A.ConclusionDuring both septal eruption (P4) and elongation (P12), alveolar PDGF-Rα may enhance the propensity of fibroblasts to transdifferentiate rather than directly stimulate αSMA, which preferentially localizes to non-proliferating fibroblasts. In accordance, PDGF-Rα more dominantly influences fibroblast proliferation at P4 than at P12. In the lung, TGFβ may overshadow the antagonistic effects of PDGF-A/PDGF-Rα signaling, enhancing αSMA-abundance in PDGF-Rα-expressing fibroblasts.