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Abstract

Objective To examine the effects of short-term cyclic stretch on apoptosis in alveolar type II cells (A549). To study in vitro the direct influence of alveolar type II cells on mechanical stretch. Methods A549 were treated with different doses of lipopolysaccharide (LPS), 0 ng/ml, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1000 ng/ml, and then A549 were lengthened 5%, 15%, 30% using a FLEXCELL tension unit 4000, a vacuum-driven device that applies strain to cells, which were cultured in six-well plates coated with collagen-I, and 12 cycles/min for 4 hours. Apoptosis was measured using the flow cytometry method that measures annexin V and propidium iodide (PI) staining. The morphological changes of apoptotic cells were observed by transmission electron microscope. Results Apoptosis could be induced in alveolar type II cells (A549) by mechanical stretch. The percentage of annexin V + PI cells increased after being treated with cyclic stretch for 4 hours by 5%, 15%, 30% in all groups. The morphological features of apoptotic cells demonstrated by transmission electron microscope were as follows: shrinkage of the cell, chromatin condensation and aggregation under the nuclear membrane as a crescent or lump, membrane-encapsulated nuclear fragment or cell organ formed by invagination of the cell membrane, and apoptotic body formation followed by vacuolization. Conclusion Apoptosis induced by mechanical stretch and LPS is dose dependent. Mechanical stretch aggravates apoptosis especially in cells treated with LPS. Annexin V and PI double staining is a specific, sensitive, and quantitative method for analyzing apoptotic cells. It is also helpful to clarify the protective mechanism of low-volume ventilation in ARDS. Acknowledgement The study was funded by the 'One Hundred People' project of Shanghai Sanitary Bureau (03-77-20). Introduction Although extrapulmonary ALI/ARDS is a common clinical entity, most animal models used to study this disease are induced by direct lung injuries. Our intention was therefore to investigate whether a condition resembling ALI/ARDS develops during the course of a fecal peritonitis in pigs; in that case experimental peritonitis would also prove as a clinically relevant ARDS model. Methods In 10 anesthetized, mechanically ventilated, and instrumented pigs fecal peritonitis was induced by inoculating autologue feces pellets suspended in saline. Mechanical ventilation was set with VT = 8 ml/kg, FiO 2 to reach a SaO 2 target of >90%, PEEP = 10 cmH 2 O if PaO 2 /FiO 2 > 300 and 12 cmH 2 O if PaO 2 /FiO 2 < 300, and respiratory rate to obtain a PaCO 2 of 35-45 mmHg. Before as well as 12 and 24 hours after peritonitis induction we measured the PaO 2 /FiO 2 ratio, the total compliance of the respiratory system (C), calculated as VT/(P plateau -PEEP) and inspiratory airway resistance (R i ) calculated as (P max -P plateau ) / mean inspiratory flow. Data are mean [range]. Results For data see Table 1. During the course of the 24-hour study period, six of 10 animals developed gas exchange deteriorations consistent w...

Pharmaconutrition with Omega-3 Fatty Acids: Status Quo and Further Perspectives

“…Fish oil significantly lowered the occurrence of comorbid infection and improved survival. Similar observations were made in patients with sepsis [7] and acute respiratory distress [8,9].…”

“…Moreover, a lower re-operation rate was found and ICU-as well as hospital stay was significantly reduced in the fish oil group. Higher grade of evidence most recently was given by Pontes-Arruda in a prospective randomized clinical trial [7]. Significantly lower ventilatory support, lower ICU-stay and improved survival were found in septic patients after enteral omega-3 FA.…”

Immunonutrition for acute respiratory distress syndrome (ARDS) in adults

“…Nine of the 10 included studies used the American-European Consensus Criteria (AECC) for identification of ARDS or ALI (Elamin 2012;Gadek 1999;Gupta 2012;Parish 2014;Pontes-Arruda 2006;Rice 2011;Shirai 2015;Singer 2006;Stapleton 2011). The remaining study enrolled ventilated patients with septic shock and did not explicitly define this population as ARDS/ALI or not (Grau-Camona 2011).…”

“…Among the 10 included studies, six studies used a similar enteral preparation (Oxepa; Abbott Nutrition/Abbott Laboratories, Columbus, OH, USA) continuously supplemented with EPA, DHA, GLA, and antioxidants (Elamin 2012;Gadek 1999;Grau-Camona 2011;Pontes-Arruda 2006;Shirai 2015;Singer 2006). Four of these six studies used an isocaloric high-fat formulation (Pulmocare; Abborr Nutrition/Abbott Laboratories, Columbus, OH, USA) for control groups (Elamin 2012;Gadek 1999;Pontes-Arruda 2006;Singer 2006). The remaining two studies used a carbohydrate-based control formulation (Ensure Plus or Ensure Liquid; Abbott Laboratories, East Windsor, NJ, USA) (Grau-Camona 2011; Shirai 2015).…”

“…Five studies defined a target enteral nutrition delivery rate of 50% to 75% of basal/resting energy expenditure (BEE/REE) for the first 24 hours with variable increments to achieve 70% to 100% of BEE/REE (Elamin 2012;Gadek 1999;Pontes-Arruda 2006;Shirai 2015;Singer 2006). The duration of intervention was 7 or fewer days (Elamin 2012;Gadek 1999), 14 days (Gupta 2012…”