Prediction and validation of cell alignment along microvessels as order principle to restore tissue architecture in liver regeneration.

Only little is known about how cells coordinately behave to establish functional tissue structure and restore microarchitecture during regeneration. Research in this field is hampered by a lack of techniques that allow quantification of tissue architecture and its development. To bridge this gap, we have established a procedure based on confocal laser scans, image processing, and three-dimensional tissue reconstruction, as well as quantitative mathematical modeling. As a proof of principle, we reconstructed and modeled liver regeneration in mice after damage by CCl(4), a prototypical inducer of pericentral liver damage. We have chosen the regenerating liver as an example because of the tight link between liver architecture and function: the complex microarchitecture formed by hepatocytes and microvessels, i.e. sinusoids, ensures optimal exchange of metabolites between blood and hepatocytes. Our model captures all hepatocytes and sinusoids of a liver lobule during a 16 days regeneration process. The model unambiguously predicted a so-far unrecognized mechanism as essential for liver regeneration, whereby daughter hepatocytes align along the orientation of the closest sinusoid, a process which we named "hepatocyte-sinusoid alignment" (HSA). The simulated tissue architecture was only in agreement with the experimentally obtained data when HSA was included into the model and, moreover, no other likely mechanism could replace it. In order to experimentally validate the model of prediction of HSA, we analyzed the three-dimensional orientation of daughter hepatocytes in relation to the sinusoids. The results of this analysis clearly confirmed the model prediction. We believe our procedure is widely applicable in the systems biology of tissues.

Munich Oktoberfest experience: remarkable impact of sex and age in ethanol intoxication.

Approximately 5,000 of 6 million annual visitors of the Oktoberfest in Munich have to undergo medical treatment. Patients with alcohol intoxication without trauma or further complications are all treated in a specialized medical camp. We studied these patients in order to identify risk factors and to assess the relevance of the Glasgow Coma Score (GCS) and of ethanol blood concentrations for patient management. In 2004 totally 405 patients suffering from ethanol intoxication without trauma were treated in the medical camp. A complete set of the following data was obtained from all 405 patients: GCS, ethanol blood concentration, age, sex, blood pressure (mean, systolic and diastolic), body temperature, heart rate, blood sugar, GOT, gamma-GT, and CK. A multivariate logistic regression model was applied to identify risk factors predicting patients at increased risk of hospitalization. Low GCS (< or =8 vs. >8, OR: 4.18, CI: 1.96-8.65) low age (20-29 vs. > or =30 years, OR: 2.35, CI: 1.05-5.65) and male gender (male vs. female, OR: 3.58, CI: 1.36-9.34) independently predicted patients that had to be hospitalized. All other parameters including ethanol blood concentrations were not explanatory. Patients with GCS < or = 8 (n = 66) had a lower median blood pressure (P = 0.0312) and showed a smaller increase in blood pressure during the observation period compared to patients with GCS > 8 (P < 0.001), suggesting that this subgroup may require longer recovery periods. Men aged 20-29 years were at highest risk for hospital admission. Increased risk could not be explained by higher ethanol blood concentrations in this subgroup. Importantly, GCS < 6 does not justify endotracheal intubation in ethanol intoxicated patients, when further complications, such as trauma, can be excluded.

Cadmium, cobalt and lead cause stress response, cell cycle deregulation and increased steroid as well as xenobiotic metabolism in primary normal human bronchial epithelial cells which is coordinated by at least nine transcription factors.

Workers occupationally exposed to cadmium, cobalt and lead have been reported to have increased levels of DNA damage. To analyze whether in vivo relevant concentrations of heavy metals cause systematic alterations in RNA expression patterns, we performed a gene array study using primary normal human bronchial epithelial cells. Cells were incubated with 15 microg/l Cd(II), 25 microg/l Co(II) and 550 microg/l Pb(II) either with individual substances or in combination. Differentially expressed genes were filtered out and used to identify enriched GO categories as well as KEGG pathways and to identify transcription factors whose binding sites are enriched in a given set of promoters. Interestingly, combined exposure to Cd(II), Co(II) and Pb(II) caused a coordinated response of at least seven stress response-related transcription factors, namely Oct-1, HIC1, TGIF, CREB, ATF4, SRF and YY1. A stress response was further corroborated by up regulation of genes involved in glutathione metabolism. A second major response to heavy metal exposure was deregulation of the cell cycle as evidenced by down regulation of the transcription factors ELK-1 and the Ets transcription factor GABP, as well as deregulation of genes involved in purine and pyrimidine metabolism. A third and surprising response was up regulation of genes involved in steroid metabolism, whereby promoter analysis identified up regulation of SRY that is known to play a role in sex determination. A forth response was up regulation of xenobiotic metabolising enzymes, particularly of dihydrodiol dehydrogenases 1 and 2 (AKR1C1, AKR1C2). Incubations with individual heavy metals showed that the response of AKR1C1 and AKR1C2 was predominantly caused by lead. In conclusion, we have shown that in vivo relevant concentrations of Cd(II), Co(II) and Pb(II) cause a complex and coordinated response in normal human bronchial epithelial cells. This study gives an overview of the most responsive genes.