Developmental retardation in neonates of aldehyde reductase (AKR1A)-deficient mice is associated with low ascorbic acid and high corticosterone levels.

Aldehyde reductase encoded by the Akr1a gene catalyzes the NADPH-dependent reduction of a variety of aldehyde compounds, and it plays a role in the biosynthesis of ascorbic acid (AsA) by converting D-glucuronate to L-gulonate. Although supplementing drinking water with AsA (1.5 mg/mL) ameliorates the fertility of Akr1a-/- (KO) female mice, litter sizes in the KO mice are typically smaller than those for Akr1a+/+ (WT) mice, and about one-third of the neonates have a reduced stature. Half of the neonates in the smallest, developmentally retarded group died before weaning, and the remaining half (less than 6 g in weight) also barely grew to adulthood. While no difference was found in the number of fetuses between the KO and WT mice at 14.5-embryonic days, the sizes of the KO fetuses had already diverged. Among the organs of these retarded KO neonates at 30 d, the spleen and thymus were characteristically small. While an examination of spleen cells showed the normal proportion of immune cells, apoptotic cell death was increased in the thymus, which would lead to thymic atrophy in the retarded KO neonates. Plasma AsA levels were lower in the small neonates despite the fact that their mothers had received sufficient AsA supplementation, and the corticosterone levels were inversely higher compared to wild-type mice. Thus, insufficient AsA contents together with a defect in corticosterone metabolism might be the cause of the retarded growth of the AKR1A-deficient mice embryos and neonates.

Iron loading exerts synergistic action via a different mechanistic pathway from that of acetaminophen-induced hepatic injury in mice.

Acetaminophen (APAP) overdose is a major cause of drug-induced acute liver failure. In such cases, free iron is released from lysosomes and is transported to mitochondria where it plays a pivotal role in APAP-induced liver injury. We previously reported that ascorbic acid (Asc) markedly mitigates APAP-induced hepatic damage in aldehyde reductase (Akr1a)-knockout (KO) mice that produce about 10% Asc as wild-type (WT) mice. However, the issue of the protective mechanism of Asc in association with the status of iron remains ambiguous. To gain additional insights into this issue, we examined effects of APAP (500 mg/kg) on female KO mice under conditions of iron loading. While the KO mice without AsA supplementation were more sensitive to APAP toxicity than the WT mice, FeSO4 loading (25 mg/kg) to WT mice aggravated the hepatic injury, which was a similar extent to that of the KO mice. Supplementation of Asc (1.5 mg/ml in the drinking water) ameliorated KO mice irrespective of iron status but did not change the iron-mediated increase in the lethality in the WT mice. Hepatic cysteine and glutathione levels declined to similar extents in all mouse groups at 3 h irrespective of the iron status and largely recovered at 18 h after the APAP treatment when liver damage was evident. Asc prominently mitigated APAP toxicity in KO mice irrespective of the iron status but had no effect on the synergistic action of iron and APAP in the WT mice, suggesting that the mechanism for the deteriorating action of loaded iron is different from that of APAP toxicity.

Diabetes mellitus exacerbates citrin deficiency via glucose toxicity.

AIMS: Citrin is an aspartate/glutamate carrier that composes the malate-aspartate reduced nicotinamide adenine dinucleotide (NADH) shuttle in the liver. Citrin deficiency causes neonatal intrahepatic cholestasis (NICCD), failure to thrive and dyslipidemia (FTTDCD) and adult-onset type II citrullinemia (CTLN2). Hepatic glycolysis is essentially impaired in citrin deficiency and a low-carbohydrate diet was recommended. The lethal effect of infusion of glycerol- and fructose-containing osmotic agents was reported in these patients. Hyperalimentation was also reported to exacerbate CTLN2; however, glucose toxicity was unclear in citrin deficiency. METHODS: We studied two CTLN2 patients complicated with type 2 diabetes mellitus (DM), Case 1 presented with hyperammonemic encephalopathy accompanied with DM, while Case 2 presented with hyperammonemic encephalopathy relapse upon the onset of DM after several years' remission following supplementation with medium-chain triglycerides (MCT) and adherence to a low-carbohydrate diet. RESULTS: Insulin therapy with MCT supplementation and a low-carbohydrate diet improved hyperammonemia and liver function in Case 1. Additional insulin therapy improved hyperammonemia in Case 2. CONCLUSION: Glucose is not toxic for citrin deficiency in normoglycemia because glucose uptake and metabolism by hepatocytes are limited in normoglycemia. However, glucose becomes toxic during persistent hyperglycemia and antidiabetic therapy is indispensable for CTLN2 patients with DM.

Medium-chain triglycerides supplement therapy with a low-carbohydrate formula can supply energy and enhance ammonia detoxification in the hepatocytes of patients with adult-onset type II citrullinemia.

Citrin, encoded by SLC25A13, constitutes the malate-aspartate shuttle, the main NADH-shuttle in the liver. Citrin deficiency causes neonatal intrahepatic cholestasis (NICCD) and adult-onset type II citrullinemia (CTLN2). Citrin deficiency is predicted to impair hepatic glycolysis and de novo lipogenesis, resulting in hepatic energy deficit. Secondary decrease in hepatic argininosuccinate synthetase (ASS1) expression has been considered a cause of hyperammonemia in CTLN2. We previously reported that medium-chain triglyceride (MCT) supplement therapy with a low-carbohydrate formula was effective in CTLN2 to prevent a relapse of hyperammonemic encephalopathy. We present the therapy for six CTLN2 patients. All the patients' general condition steadily improved and five patients with hyperammonemic encephalopathy recovered from unconsciousness in a few days. Before the treatment, plasma glutamine levels did not increase over the normal range and rather decreased to lower than the normal range in some patients. The treatment promptly decreased the blood ammonia level, which was accompanied by a decrease in plasma citrulline levels and an increase in plasma glutamine levels. These findings indicated that hyperammonemia was not only caused by the impairment of ureagenesis at ASS1 step, but was also associated with an impairment of glutamine synthetase (GS) ammonia-detoxification system in the hepatocytes. There was no decrease in the GS expressing hepatocytes. MCT supplement with a low-carbohydrate formula can supply the energy and/or substrates for ASS1 and GS, and enhance ammonia detoxification in hepatocytes. Histological improvement in the hepatic steatosis and ASS1-expression was also observed in a patient after long-term treatment.

Medium-chain triglyceride supplementation under a low-carbohydrate formula is a promising therapy for adult-onset type II citrullinemia.

BACKGROUND: Citrin, encoded by SLC25A13, is a component of the malate-aspartate shuttle, which is the main NADH-transporting system in the liver. Citrin deficiency causes neonatal intrahepatic cholestasis (NICCD), which usually resolves within the first year of life. However, small numbers of adults with citrin deficiency develop hyperammonemic encephalopathy, adult-onset type II citrullinemia (CTLN2), which leads to death due to cerebral edema. Liver transplantation is the only definitive therapy for patients with CTLN2. We previously reported that a lactose (galactose)-restricted and medium-chain triglyceride (MCT)-supplemented formula is notably effective for patients with NICCD. Citrin deficiency may impair the glycolysis in hepatocytes because of an increase in the cytosolic NADH/NAD+ ratio, leading to an energy shortage. MCT administration can provide energy to hepatocytes and was expected to have a good effect on CTLN2. METHODS: An MCT supplementation therapy under a low-carbohydrate formula was administered to five patients with CTLN2. Four of the patients had episodes of hyperammonemic encephalopathy, and one patient had postprandial hyperammonemia with no symptoms. RESULTS: One of the patients displaying hyperammonemic encephalopathy completely recovered with all normal laboratory findings. Others notably improved in terms of clinical and or laboratory findings with no hyperammonemic symptoms; however, the patients displayed persistent mild citrullinemia and occasionally had postprandial mild hyperammonemia most likely due to an irreversible change in the liver. CONCLUSIONS: An MCT supplement can provide energy to hepatocytes and promote hepatic lipogenesis, leading to a reduction in the cytosolic NADH/NAD+ ratio. MCT supplementation under a low-carbohydrate formula could be a promising therapy for CTLN2 and should also be used to prevent CTLN2 to avoid irreversible liver damage.

[Extracorporeal partial nephrectomy and auto-transplantation after presurgical targeted therapy with tyrosine kinase inhibitors for renal cell cancer].

A 74-year-old woman who had previously undergone left nephrectomy because of calculi was referred to our department with a right renal mass that was detected by computed tomography (CT) during treatment for pyelonephritis. Repeated CT showed a contrast-enhanced 4.7 cm tumor close to the renal sinus, and no metastatic lesion was detected. Sunitinib was administered as a presurgical therapy ; however, the patient experienced grade 3 neutropenia and thrombocytopenia, and sunitinib was discontinued. Sorafenib was administered 7 days after discontinuation of sunitinib ; however, the patient experienced febrile neutropenia and rash, and sorafenib was discontinued. Extracorporeal partial nephrectomy and auto-transplantation were performed 24 days after discontinuation of sorafenib. Though peri-graft abscess was suspected to be present and resolved by antibacterial therapy, severe complications were not experienced, and the patient did not require dialysis therapy after surgery. There was no evidence of recurrence at 30 months after the surgery.

Local cell proliferation in rheumatoid synovial tissue: analysis by cyclin expression.

The immunohistochemical staining of cyclins was done to evaluate the proliferating cells in synovial tissue of rheumatoid arthritis (RA). Synovial specimens obtained from 18 patients with RA, 12 with osteoarthritis (OA), and 8 with traumatic arthritis (TA) were used for immunostaining of cyclins A and B1 and proliferating cell nuclear antigen (PCNA). The positive cells in lining layer (synoviocytes) and sublining layer (lymphoid and nonlymphoid cells) were counted. Moreover, the relationship between the frequency of their positive cells and clinical data of RA patients was analyzed statistically. In general, cyclin-A-, cyclin-B1-, and PCNA-positive cells in RA were more frequently observed as compared with those in OA and TA. Significant differences were found between RA and OA or TA in cyclin-A-, cyclin-B1-, and PCNA-positive sublining lymphoid cells, between RA and OA or TA in cyclin-B1- and PCNA-positive sublining nonlymphoid cells, and between RA and OA in cyclin-B1-positive synoviocytes. The ratio of cyclin-A- or cyclin-B1-positive cells per PCNA-positive cells was significantly higher in sublining lymphoid cells in RA than TA and in sublining lymphoid and nonlymphoid cells of RA than OA or TA. Moreover, a better relationship was observed between the frequency of cyclin-A-positive synoviocytes and age and between cyclin-A-positive sublining nonlymphoid cells and duration of the disease in RA patients. Our data demonstrated clearly that synoviocytes, as well as sublining lymphoid and nonlymphoid cells, could divide in situ, and more frequent cell division and a higher ratio of cyclin-A- or cyclin-B1-positive/PCNA-positive sublining cells could occur in RA than OA and TA.