Determination of in vivo protein synthesis in human palatine tonsil

Dysregulation of mitochondrial dynamics and the muscle transcriptome in ICU patients suffering from sepsis induced multiple organ failure

Background

Septic patients treated in the intensive care unit (ICU) often develop multiple organ failure including persistent skeletal muscle dysfunction which results in the patient's protracted recovery process. We have demonstrated that muscle mitochondrial enzyme activities are impaired in septic ICU patients impairing cellular energy balance, which will interfere with muscle function and metabolism. Here we use detailed phenotyping and genomics to elucidate mechanisms leading to these impairments and the molecular consequences.

Methodology/Principal Findings

Utilising biopsy material from seventeen patients and ten age-matched controls we demonstrate that neither mitochondrial in vivo protein synthesis nor expression of mitochondrial genes are compromised. Indeed, there was partial activation of the mitochondrial biogenesis pathway involving NRF2α/GABP and its target genes TFAM, TFB1M and TFB2M yet clearly this failed to maintain mitochondrial function. We therefore utilised transcript profiling and pathway analysis of ICU patient skeletal muscle to generate insight into the molecular defects driving loss of muscle function and metabolic homeostasis. Gene ontology analysis of Affymetrix analysis demonstrated substantial loss of muscle specific genes, a global oxidative stress response related to most probably cytokine signalling, altered insulin related signalling and a substantial overlap between patients and muscle wasting/inflammatory animal models. MicroRNA 21 processing appeared defective suggesting that post-transcriptional protein synthesis regulation is altered by disruption of tissue microRNA expression. Finally, we were able to demonstrate that the phenotype of skeletal muscle in ICU patients is not merely one of inactivity, it appears to be an actively remodelling tissue, influenced by several mediators, all of which may be open to manipulation with the aim to improve clinical outcome.

Conclusions/Significance

This first combined protein and transcriptome based analysis of human skeletal muscle obtained from septic patients demonstrated that losses of mitochondria and muscle mass are accompanied by sustained protein synthesis (anabolic process) while dysregulation of transcription programmes appears to fail to compensate for increased damage and proteolysis. Our analysis identified both validated and novel clinically tractable targets to manipulate these failing processes and pursuit of these could lead to new potential treatments.

Enhanced in vivo protein synthesis in circulating immune cells of ICU patients

Insufficient function of the immune system contributes to a poor prognosis in intensive care unit (ICU) patients. However, the immune system function is not easily monitored and evaluated. In vivo protein synthesis determination in immune competent cells offers a possibility to quantify immunological activation. The aim of this descriptive study was to determine the in vivo fractional protein synthesis rate (FSR) in immune cells of ICU patients during the initial phase of the critical illness. Patients (n = 20) on ventilator treatment in the general ICU were studied during their first week of ICU stay. FSR was determined in circulating T lymphocytes, mononuclear cells, the whole population of blood leukocytes, and in stationary immune cells of palatine tonsils during a 90-min period by a flooding technique. Healthy, adult subjects (n = 11), scheduled for elective ear, nose, and throat surgery served as a control group. The FSR in leukocytes and mononuclear cells of ICU patients was higher compared with the control group. In contrast, the FSR of circulating T lymphocytes and of tonsillar cells was not different from that in the healthy subjects. In summary, the ICU patients showed a distinct polarization of metabolic responses during the initial phase of the critical illness. The in vivo rate of protein synthesis was high in the circulating mononuclear cells and leukocytes, reflecting enhanced metabolic activity in these cell populations. Determination of the in vivo protein synthesis rate may be used as a tool to obtain additional information on activation of the immune system.

Tonsil Surgery in Youths: Good Results With A Less Invasive Method

OBJECTIVE

Comparison of two types of tonsil surgery for 16- to 25-year-old patients, with respect to primary morbidity, snoring, and recurrent infections after 1 year. Teenagers and young adults are a significant proportion (26%) of the population that receive tonsil surgery each year and appear to suffer more pain than younger children. Recurrent tonsillitis, in combination with obstructive problems, is the main indication for surgery.

METHOD

One hundred fourteen patients 16 to 25 years of age were randomized to tonsillotomy (TT) with radiosurgery (RF) (Ellman International) or to cold tonsillectomy (TE). Pain and analgesics were logged until patients were pain free.

RESULTS

Thirty-two patients were operated on with TT and 44 with TE. The TT group had less blood loss during surgery and no postoperative bleedings, compared with the TE group (2 primary and 4 late hemorrhages). The TT group recorded significantly less pain from the first day, had less need of analgesics (diclofenac and paracetamol), and were pain free and in school/at work 4 days earlier than the TE group. After 7 days, the TE patients had lost a mean of 1.8 kg compared with TT, with no significant weight loss. After 1 year, both groups were satisfied. The positive effect on snoring was the same for both groups. There were few throat infections in both groups.

CONCLUSION

TT with RF is an effective method for tonsil surgery for many teenagers and young adults, with much less postoperative morbidity than regular TE. Long-term follow-up is necessary.