Light-induced modulation of the mitochondrial respiratory chain activity: possibilities and limitations.

Biological effects of high fluence low-power (HFLP) lasers have been reported for some time, yet the molecular mechanisms procuring cellular responses remain obscure. A better understanding of the effects of HFLP lasers on living cells will be instrumental for the development of new experimental and therapeutic strategies. Therefore, we investigated sub-cellular mechanisms involved in the laser interaction with human hepatic cell lines. We show that mitochondria serve as sub-cellular "sensor" and "effector" of laser light non-specific interactions with cells. We demonstrated that despite blue and red laser irradiation results in similar apoptotic death, cellular signaling and kinetic of biochemical responses are distinct. Based on our data, we concluded that blue laser irradiation inhibited cytochrome c oxidase activity in electron transport chain of mitochondria. Contrary, red laser triggered cytochrome c oxidase excessive activation. Moreover, we showed that Bcl-2 protein inhibited laser-induced toxicity by stabilizing mitochondria membrane potential. Thus, cells that either overexpress or have elevated levels of Bcl-2 are protected from laser-induced cytotoxicity. Our findings reveal the mechanism how HFLP laser irradiation interfere with cell homeostasis and underscore that such laser irradiation permits remote control of mitochondrial function in the absence of chemical or biological agents.

Beyond an Obvious Cause of Cholestasis in a Toddler: Compound Heterozygosity for ABCB11 Mutations.

A 27-month-old girl presented with a short history of jaundice initially attributed to drug-induced liver injury. During the preceding 20 days, she had received a 10-day course of cefprozil and 2 doses of a homeopathic preparation of cantharidin for cystitis. Severe conjugated hyperbilirubinemia was present with normal γ-glutamyl transpeptidase activity. Liver biopsy revealed marked canalicular and hepatocellular cholestasis, with moderate hepatocellular disarray, as well as evidence of chronicity, including moderate portal-tract and perisinusoidal fibrosis. Immunohistochemical studies revealed that bile salt export pump expression was preserved, whereas canalicular γ-glutamyl transpeptidase expression was largely absent. An inherited cholestatic disorder was suspected. The entire coding region of ABCB11, encoding bile salt export pump, was analyzed. The patient was found to be a compound heterozygote for the missense mutation c.3148C>T (p.Arg1050Cys) associated with benign recurrent intrahepatic cholestasis type 2 in the homozygous state and for the nonsense mutation c.3904G>T (p.Glu1302Ter) associated with progressive familial intrahepatic cholestasis type 2. Despite initial improvement with ursodeoxycholic acid, over the course of 5 years the patient developed cirrhosis that required liver transplant. Our report emphasizes the need for molecular studies even in patients with putatively "explained" cholestasis to reveal the entire spectrum of inherited cholestatic disorders.

Hepcidin knockout mice spontaneously develop chronic pancreatitis owing to cytoplasmic iron overload in acinar cells.

Iron is both an essential and a potentially toxic element, and its systemic homeostasis is controlled by the iron hormone hepcidin. Hepcidin binds to the cellular iron exporter ferroportin, causes its degradation, and thereby diminishes iron uptake from the intestine and the release of iron from macrophages. Given that hepcidin-resistant ferroportin mutant mice show exocrine pancreas dysfunction, we analysed pancreata of aging hepcidin knockout (KO) mice. Hepcidin and Hfe KO mice were compared with wild-type (WT) mice kept on standard or iron-rich diets. Twelve-month-old hepcidin KO mice were subjected to daily minihepcidin PR73 treatment for 1 week. Six-month-old hepcidin KO mice showed cytoplasmic acinar iron overload and mild pancreatitis, together with elevated expression of the iron uptake mediators DMT1 and Zip14. Acinar atrophy, massive macrophage infiltration, fatty changes and pancreas fibrosis were noted in 1-year-old hepcidin KO mice. As an underlying mechanism, 6-month-old hepcidin KO mice showed increased pancreatic oxidative stress, with elevated DNA damage, apoptosis and activated nuclear factor-κB (NF-κB) signalling. Neither iron overload nor pancreatic damage was observed in WT mice fed iron-rich diet or in Hfe KO mice. Minihepcidin application to hepcidin KO mice led to an improvement in general health status and to iron redistribution from acinar cells to macrophages. It also resulted in decreased NF-κB activation and reduced DNA damage. In conclusion, loss of hepcidin signalling in mice leads to iron overload-induced chronic pancreatitis that is not seen in situations with less severe iron accumulation. The observed tissue injury can be reversed by hepcidin supplementation. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

1H MR spectroscopy as a diagnostic tool for cerebral creatine deficiency.

OBJECTIVE: Total creatine (tCr) constitutes one of the most prominent signals in human brain MR spectra. A significant decrease in the tCr signal indicates a severe disorder of creatine metabolism. We describe the potential of 1H MR spectroscopy in differential diagnosis of creatine transporter (SLC6A8) deficiency syndrome. MATERIALS AND METHODS: Two siblings, a 7-year-old female presenting with mild psychomotor delay, and a 5-year-old male with severe psychomotor retardation, epilepsy and autistic spectrum of problems including speech delay, underwent MR examination because of suspected creatine deficiency. After the MRI examination, 1H MR spectroscopy using the CSI technique was performed. RESULTS: Metabolic images of N-acetylaspartate, tCr and choline concentrations showed a very low tCr signal in the male, which was approximately three times lower than in his sister (male/female/controls: tCr=1.6/4.6/7.5 mM). Despite creatine supplementation, no improvement in clinical status and tCr concentration in the MR spectra of the male was observed and diagnosis of SLC6A8 deficiency was proposed. Sequence analysis of the SLC6A8 gene revealed a novel pathogenic frameshift mutation c.219delC; p.Asn74ThrfsX23, hemizygous in the male and heterozygous in the female. CONCLUSIONS: The diagnosis of X-linked mental retardation caused by the SLC6A8 deficiency can be independently established by 1H MR spectroscopy.

Revised King's College score for liver transplantation in adult patients with Wilson's disease.

Fulminant Wilson's disease (WD) is almost invariably fatal, and liver transplantation is the only life-saving treatment. Decompensated chronic WD usually responds to chelation therapy. Our aim was to validate 3 published scoring systems for deciding between chelation treatment and liver transplantation in patients with chronic decompensated and fulminant WD. Model for end-stage liver disease (MELD) score, as well as WD prognostic index (WPI) and its recently revised version (RWPI) were evaluated as predictors of the safety for chelation therapy. A group of 14 adult patients with decompensated chronic WD who improved on penicillamine treatment were compared with 21 patients with fulminant WD. The diagnosis of WD was based on increased urinary copper excretion and confirmed by elevated liver copper content and/or mutation analysis of the WD gene. The MELD score, WPI, and RWPI were calculated for all patients with WD. The accuracy of the MELD score, WPI, and RWPI for prediction of response to chelation therapy in patients with decompensated chronic WD was 0.968, 0.980, and 0.993, respectively. None of the decompensated chronic WD patients had a MELD score >30, RWPI >11, or WPI >7. RWPI showed the highest accuracy and the lowest false negativity compared with WPI and MELD. In conclusion, our data indicate that RWPI, originally proposed for pediatric patients, is also useful for adults.