Hans Barle

Synthesis rates of total liver protein and albumin are both increased in patients with an acute inflammatory response

The general perception that catabolism and inflammation are associated with a high synthesis rate of total liver protein and a low albumin synthesis rate has been challenged in recent years by several studies in man, indicating that the synthesis rate of albumin in response to a catabolic insult is increased rather than decreased. Thus changes in liver protein synthesis rates in conjunction with catabolism and acute inflammation in man need to be characterized better. The aim of the present study was to measure protein synthesis rates of total liver protein and albumin during a state of acute inflammation. Patients (n = 10) undergoing acute laparoscopic cholecystectomy due to acute cholecystitis were investigated. FSRs (fractional synthesis rates) of total liver protein (liver biopsy specimens) and albumin (plasma samples) were investigated as early as possible during the surgical procedure, using a flooding dose of L-[2H5]phenylalanine. The results were compared with a reference group of patients without cholecystitis undergoing elective laparoscopic cholecystectomy (n = 17). FSR of total liver protein was 60% higher (P < 0.001) and the FSR of albumin was 45% higher (P < 0.01) in the cholecystitis patients compared with the control group. In conclusion, the synthesis rates of total liver protein and albumin are both increased in patients with an acute general inflammatory reaction undergoing laparoscopic cholecystectomy.

Depression of liver protein synthesis during surgery is prevented by growth hormone.

This study was undertaken to elucidate the specific effects of growth hormone (GH) on liver protein metabolism in humans during surgery. Otherwise healthy patients scheduled for elective laparoscopic cholecystectomy were randomized into controls (n = 9) or pretreatment with 12 units of GH for 1 day (GH 1, n = 9) or daily for 5 days (GH 5, n = 10). The fractional synthesis rate of liver proteins, as assessed by flooding with [2H5]phenylalanine, was higher in the GH 5 group (22.0 +/- 6.9%/day, mean +/- SD, P < 0.05) than in the control (16.1 +/- 3.1%/day) and GH 1 (16.5 +/- 5.5%/day) groups. During surgery, the fraction of polyribosomes in the liver, as assessed by ribosome analysis, decreased in the control group by approximately 12% (P < 0.01) but did not decrease in the GH-treated groups. In addition, the concentrations of the essential amino acids and aspartate in the liver decreased in response to GH treatment. In conclusion, GH pretreatment decreases hepatic free amino acid concentrations and preserves liver protein synthesis during surgery.This study was undertaken to elucidate the specific effects of growth hormone (GH) on liver protein metabolism in humans during surgery. Otherwise healthy patients scheduled for elective laparoscopic cholecystectomy were randomized into controls ( n = 9) or pretreatment with 12 units of GH for 1 day (GH 1, n = 9) or daily for 5 days (GH 5, n = 10). The fractional synthesis rate of liver proteins, as assessed by flooding with [2H5]phenylalanine, was higher in the GH 5 group (22.0 ± 6.9%/day, mean ± SD, P < 0.05) than in the control (16.1 ± 3.1%/day) and GH 1 (16.5 ± 5.5%/day) groups. During surgery, the fraction of polyribosomes in the liver, as assessed by ribosome analysis, decreased in the control group by ∼12% ( P < 0.01) but did not decrease in the GH-treated groups. In addition, the concentrations of the essential amino acids and aspartate in the liver decreased in response to GH treatment. In conclusion, GH pretreatment decreases hepatic free amino acid concentrations and preserves liver protein synthesis during surgery.

The synthesis rate of albumin decreases during laparoscopic surgery

In previous studies, a decline in total liver protein synthesis during elective laparoscopic surgery has been observed. However, when albumin synthesis was measured in parallel no apparent influence of the procedure was detected. The aim of the present study was to specifically investigate the effect of a laparoscopic procedure on albumin synthesis. Female (n = 9) patients scheduled for elective laparoscopic cholecystectomy as a consequence of cholecystolithiasis were investigated. The fractional synthesis rate (FSR) of albumin was investigated twice in each patient, before and during surgery (2–3 h apart), employing l‐[2H5]phenylalanine and gas chromatography mass spectrometry. The FSR of albumin decreased from 7·3 ± 1·2% per day before surgery to 6·2 ± 1·4% per day during the procedure (P<0·01), whereas the corresponding absolute synthesis rates of albumin decreased from 114 ± 24 to 86 ± 16 mg kg−1 day−1, respectively (P<0·001). In conclusion, the synthesis rate of albumin decreased during a laparoscopic surgery procedure. However, the characteristics for this decrease differ from those previously observed for total liver protein synthesis.

The Effects of Short-Term Parenteral Nutrition on Human Liver Protein and Amino Acid Metabolism During Laparoscopic Surgery

BACKGROUND This study was undertaken to elucidate the specific effects of short-term artificial nutrition on human liver protein metabolism. METHODS Thirty patients undergoing elective laparoscopic cholecystectomy were studied: a control group (n = 16) and a group that received total parenteral nutrition (TPN; n = 14). The nutrition consisted of a balanced i.v. solution of nutrients (17.5 nonprotein kcal/kg body wt, 50% fat, 50% carbohydrates, and 0.1 gN/kg) that was discontinued when the investigation was finished, after a total infusion time of 8.6 +/- 1.0 hours. A liver biopsy specimen was taken as soon as possible after surgery was started, for the determination of the free hepatic amino acid concentrations. In 16 of the patients, L[2H5]phenylalanine was given by i.v. to determine the fractional synthesis rate of total liver protein in a second liver biopsy specimen taken approximately 30 minutes later. RESULTS The fractional synthesis rate of total liver protein was 15.2% +/- 4.7%/d in the TPN group (n = 7), which was not different from that of the control group (17.7% +/- 3.8%/d, n = 9). However, the free hepatic concentrations of alanine (p < .05) and the essential amino acids increased (p < .001) in the TPN group, whereas the total hepatic amino acid concentrations were comparable between the groups. CONCLUSION Thus short-term TPN induced specific changes of the free hepatic amino acid concentrations, whereas total liver protein synthesis remained unaffected by the nutrition.

Hypoventilation does not explain the impaired quality of sleep in postpolio patients ventilated noninvasively vs. invasively

In a previous study, it was found that patients treated with noninvasive ventilation (NIV) reported larger dysfunctions in sleep-related parameters as assessed with the Sickness Impact Profile (SIP) and Health Index questionnaires than those treated with tracheostomy. The aim of the current study was to further evaluate these sleep limitations and relate these limitations to blood gas analyses in the groups to investigate, if the differences could be related to differences in the efficacy of ventilation. We compared postpolio patients treated with tracheostomy (PPT, n = 17), NIV (PPN, n = 14) and patients with neuromuscular disorders treated with NIV (NMN, n = 15). Significantly fewer patients in the PPT group scored large dysfunctions in the SIP sleep (SIP score >10 points) compared with the PPN and NMN patients. The PPT patients scored significantly higher regarding quality of sleep and less sense of tiredness than the PPN and NMN patients. No differences were found between the groups regarding blood gas parameters neither before nor during or after the study period. In conclusion, postpolio patients treated with invasive home mechanical ventilation seem to experience better sleep and less sense of tiredness than patients on NIV. These differences cannot be explained by differences in alveolar ventilation as assessed with blood gas analyses.