Effects of high tidal volume mechanical ventilation on production of cytokines, iNOS, and MIP-1ß proteins in pigs.

The aim of this study was to investigate longitudinal changes of the pulmonary inflammatory process as a result of mechanical stress due to mechanical ventilation. The concentrations of IL-8, TNF-α, MIP-1ß, nitrites/nitrates, and inducible nitric oxide synthases (iNOS) were investigated indicate in bronchoalveolar lavage (BAL). Twenty-three piglets were divided into three groups. Group I: animals breathing spontaneously; group II: mechanical ventilation (tidal volume (TV) = 7 mL/kg, PEEP = 5 cmH(2)O); group III: mechanical ventilation (TV = 15 mL/kg, PEEP = 0 cmH(2)0). Concentrations of BAL nitrites/nitrates from groups II and III increased during the first hour of mechanical ventilation (P = .03 and .02, respectively). The highest expression of iNOS was observed during the first hour in groups II and III. IL-8 concentration increased significantly in groups II and III. Production of TNF-α increased significantly in group III during the second and third hour (P = .01). Concentration of MIP-1ß was significantly increased in groups II and III after the first hour (P = .012 and P = .008, respectively).

The impact of mitochondrial tRNA mutations on the amount of ATP synthase differs in the brain compared to other tissues.

The impact of point mutations in mitochondrial tRNA genes on the amount and stability of respiratory chain complexes and ATP synthase (OXPHOS) has been broadly characterized in cultured skin fibroblasts, skeletal muscle samples, and mitochondrial cybrids. However, less is known about how these mutations affect other tissues, especially the brain. We have compared OXPHOS protein deficiency patterns in skeletal muscle mitochondria of patients with Leigh (8363G>A), MERRF (8344A>G), and MELAS (3243A>G) syndromes. Both mutations that affect mt-tRNA(Lys) (8363G>A, 8344A>G) resulted in severe combined deficiency of complexes I and IV, compared to an isolated severe defect of complex I in the 3243A>G sample (mt-tRNA(LeuUUR). Furthermore, we compared obtained patterns with those found in the heart, frontal cortex, and liver of 8363G>A and 3243A>G patients. In the frontal cortex mitochondria of both patients, the patterns of OXPHOS deficiencies differed substantially from those observed in other tissues, and this difference was particularly striking for ATP synthase. Surprisingly, in the frontal cortex of the 3243A>G patient, whose ATP synthase level was below the detection limit, the assembly of complex IV, as inferred from 2D-PAGE immunoblotting, appeared to be hindered by some factor other than the availability of mtDNA-encoded subunits.

Ultrastructural changes of mitochondria in the cultivated skin fibroblasts of patients with point mutations in mitochondrial DNA.

Mitochondrial disorders represent a heterogeneous group of multisystem diseases with extreme variability in clinical phenotype. The diagnosis of mitochondrial disorders relies heavily on extensive biochemical and molecular analyses combined with morphological studies including electron microscopy. Although muscle is the tissue of choice for electron microscopic studies, the authors investigated cultivated human skin fibroblasts (HSF) harboring 3 different pathologic mtDNA mutations: 3243A > G, 8344A > G, 8993T > G. They addressed to the possibility of whether mtDNA mutations influence mitochondrial morphology in HSF and if ultrastructural changes of mitochondria may be used for differential diagnostics of mitochondrial disorders caused by mtDNA mutations. Ultrastructural analysis of patients' HSF revealed a heterogeneous mixture of mainly abnormal, partially swelling mitochondria with unusual and sparse cristae. The most characteristic cristal abnormalities were heterogeneity in size and shapes or their absence. Typical filamentous and branched mitochondria with numerous cristae as appeared in control HSF were almost not observed. In all lines of cultured HSF with various mtDNA mutations, similar ultrastructural abnormalities and severely changed mitochondrial interior were found, although no alterations in function and amount of OXPHOS were detected by routinely used biochemical methods in two lines of cultured HSF. This highlights the importance of morphological analysis, even in cultured fibroblasts, in diagnostics of mitochondrial disorders.