PubMed · 14811409
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W WILBRANDT. 1950. [Problems in permeability].. https://pubmed.ncbi.nlm.nih.gov/14811409/
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Mast cells (MCs) are multifunctional effector cells of the immune system. MCs were originally thought to be involved in IgE-associated immediate hypersensitivity and allergic disorders, but it is now known that they contain or elaborate an array of mediators with a multitude of effects on many other cells. A number of studies have found that MCs are involved in various liver diseases. Although still controversial, they seem to be involved in the liver's fibrotic response to chronic inflammation and parasitic infection. Hepatic fibrosis is the most frequent liver response to toxic, infectious, or metabolic agents. During the establishment of this pathological condition, there is an increase in the components of the basement membrane that leads to continuous basement membrane-like structures being raised within Disse's space and a decrease in the number of sinusoid endothelial fenestrae. This leads to a complex process called "sinusoidal capillarization." At the cellular level, liver fibrogenesis is initiated by hepatocyte necrosis, which induces the recruitment of a large number of inflammatory cells, including MCs, which can be considered the primary effectors of the process changing sinusoidal endothelial cells into capillary-type endothelial cells. We review the roles played by MCs in hepatic chronic diseases and describe a biopsy section of hepatic tissue taken from a patient with chronic C virus-related hepatitis showing diffuse sinusoidal capillarization and a high density of MCs. This observation has led us to hypothesize a relationship between these highly specialized cells and sinusoidal capillarization.
In Pompe disease, a genetic deficiency of lysosomal acid alpha-glucosidase, glycogen accumulates abnormally in the lysosomes of skeletal, cardiac and smooth muscle, and contributes to clinically progressive and debilitating muscle weakness. The present study involved 8 infantile-onset Pompe patients, treated weekly with 10 mg/kg of recombinant human acid alpha-glucosidase (rhGAA). Muscle biopsies were obtained at baseline, 12 and 52 weeks post-treatment to establish an indicator of efficacy. Several histologic strategies were employed to characterize changes in pre- and post-treatment samples, including high-resolution light microscopy and digital histomorphometry, electron microscopy, capillary density and fiber type analysis, and confocal microscopy for satellite cell activation analysis. Histomorphometric analysis was performed on muscle samples to assess glycogen depletion in response to enzyme replacement therapy (ERT). The extent of glycogen clearance varied widely among these patient samples, and correlated well with clinical outcome. Low glycogen levels, mild ultrastructural damage, a high proportion of type I fibers, and young age at baseline were all features associated with good histologic response. There was no correlation between capillary density and glycogen clearance, and activated satellite cell levels were shown to be higher in post-treatment biopsies with poor histologic responses. This histopathologic study of infantile Pompe disease provides detailed insight into the cellular progression of the disease and its response to therapy while highlighting a number of methodologies which may be employed to assess regression or progression of the associated pathology. As enzyme replacement therapy becomes more prevalent for the treatment of lysosomal storage diseases, such evaluation of post-treatment pathology will likely become a more common occurrence in the daily practice of pathologists.
AIMS: Alveolar gas diffusion (DLCO) is impaired in chronic heart failure (CHF). Diffusion depends on membrane diffusion (DM) and the amount of blood participating in gas exchange (VC). How DM, VC, and the alveolar-capillary unit behave in relationship to CHF severity is unknown. METHODS AND RESULTS: We measured pulmonary function, including DLCO, DM, VC, and alveolar volume (VA), in 191 CHF patients in NYHA class I-III. CHF patients were grouped accordingly to peak exercise oxygen uptake (pVO(2)): group <12 mL/min/kg (n=24), group 12-16 (n=76), group 16-20 (n=64), and group >20 (n=27). DLCO, DM, VC, and VA were lowest in severe CHF and were linearly related to pVO(2) (DLCO, r=0.577, P<0.001; DM, r=0.490, P<0.001; VC, r=0.216, P<0.01; VA, r=0.565, P<0.01). DM/VC ratio, an index of the alveolar-capillary unit efficiency, was higher in group <12 (0.49+/-0.39 mL/min/mmHg/mL) and >20 (0.46+/-0.29), compared with 12-16 (0.34+/-0.19) and 16-20 (0.35+/-0.17). CONCLUSION: DLCO progressively worsens as CHF severity increases due to reduction in lung tissue participating to gas exchange (low VC and VA). In severe CHF, the few working alveolar-capillary units are the most efficient as shown by the high DM/VC. This is useful for maintaining gas exchange efficiency in severe CHF.