Regulation of human erythrocyte metabolism by insulin: cellular distribution of 6-phosphofructo-1-kinase and its implication for red blood cell function

Human erythrocytes are highly specialized cells whose function is oxygen transport. These cells' sole metabolic source of energy is the fermentation of glucose via glycolysis. They contain an active insulin receptor and respond to insulin by increasing phosphorylation of tyrosine residues in several proteins. However, no metabolic effects have yet been associated with activation of this receptor in human erythrocytes. Here, we show that insulin increases the rate of glycolysis in human erythrocytes. Lactate production increased 56 and 173% in the presence of 10 and 100 nM insulin, respectively. A higher insulin concentration (1000 nM) partially reversed the stimulation of glycolysis. These effects occur through activation of the key glycolytic enzyme 6-phosphofructo-1-kinase, which exhibits the same pattern of modulation by insulin as seen for glycolytic flux. This modulation also occurs physiologically since ex vivo experiments revealed 50% stimulation of 6-phosphofructo-1-kinase (PFK) activity following a high carbohydrate meal. Insulin increases phosphorylation of PFK and redistributes the enzyme in red blood cells, causing it to detach from the erythrocyte membrane: upon insulin stimulation, the amount of enzyme associated with the plasma decreases by 86%. Detachment is a common mechanism of enzyme activation. As a consequence, insulin prevents up to 68% of red cells hemolysis. These results show that insulin regulates erythrocyte glycolysis and viability and suggest that this regulation is associated to other erythrocyte functions such as oxygen transport. Finally, we suggest that this regulatory mechanism might be compromised in patients with diabetes mellitus.     

Hepatitis C virus infection and related liver disease in children of mothers with antibodies to the virus

Objective: To evaluate the clinical, biochemical, and virologic features associated with hepatitis C virus (HCV) infection acquired early in life from mothers with antibodies to HCV (anti-HCV).Study design: Multicenter prospective-retrospective study in Italian children.Patients: Two groups of children were investigated. Group 1 included 14 infants, born to mothers with anti-HCV but without human immunodeficiency virus infection, who became seropositive for HCV RNA during the first year of life and were thus considered infected. Group 2 included 16 children with chronic hepatitis C, aged 1 ½ to 14 years, whose mothers were the unique potential source of infection. Both groups were followed for 12 to 48 months.Methods: Alanine transaminase (ALT), anti-HCV, and HCV RNA were investigated by the polymerase chain reaction on entry to the study and during follow-up.Results: All children in group 1 had anti-HCV throughout follow-up, and all had ALT abnormalities, ranging from 1.5 to 10.5 times the normal value during the first 12 months. During further follow-up, 5 of 10 children had HCV RNA with abnormal ALT values, 3 had a return to normal of the ALT values but continued to have viremia, and 2 eventually had normal ALT values and clearance of HCV RNA. Of the 16 children in group 2, all were free of symptoms and 62% had only slight ALT elevations; 7 who underwent liver biopsy had histologic features of minimal or moderate hepatitis.Conclusions: HCV infection acquired early in life from mothers with anti-HCV is usually associated with biochemical features of liver damage during the first 12 months of life. Progression to chronicity seems to occur in the majority of cases, although HCV-associated liver disease is likely to be mild throughout infancy and childhood. (J Pediatr 1997;130:990-3)     

Cryptogenic chronic liver disease and hepatitis C virus infection in children.

The clinical features of 'cryptogenic' chronic liver disease and the prevalence of antibody to hepatitis C virus (HCV) in serum have been investigated in 33 Italian children (mean age 5 years). The diagnosis was based on the persistence of increased alanineaminotransferase values for longer than 6 months after the exclusion of biliary diseases, of extra-hepatic causes of hypertransaminasemia, of infection with known hepatotropic viruses and of autoimmune or metabolic disorders. Five patients had been transfused early in life, three had undergone surgery and one girl's mother had had acute non-A, non-B hepatitis during pregnancy. The remaining patients had no history of overt parenteral exposure. At presentation only 11 patients were symptomatic, the others had been referred after a check-up for intercurrent diseases. Liver histology performed in 21 cases showed persistent or mild active hepatitis in 18 cases and severe hepatitis or cirrhosis in three cases. Anti-HCV antibodies were found in 48% of the cases, including 88% with obvious exposure and 33% of the remaining cases. During a mean follow-up period of 5 years (range 1-14 years) only 11% of the cases achieved sustained biochemical remission, although none developed signs of liver failure. There was no significant difference in the clinical features and outcome of the disease between anti-HCV-positive and -negative patients. The results of this study suggest that HCV is implicated in most cases of 'cryptogenic' chronic liver disease observed in Italian children with a history of parenteral exposure and in at least one-third of the cases without overt exposure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hepatitis C virus genotypes in chronic hepatitis C of children

SUMMARY. Several hepatitis C virus (HCV) genotypes have been recently identified and genotype 1b has been correlated with severe liver disease and a poor response to interferon therapy. HCV infection in children is an interesting model for evaluation of the relationship between HCV genotypes and liver disease, because of its relatively short duration and the infrequent association with confounding cofactors. We have investigated HCV genotypes, using a dot-blot hybridization assay with genotype-specific probes, in 36 Italian children with chronic hepatitis C who were otherwise well and had no other underlying disease. Only four patients were symptomatic; liver histology, obtained in 3 3 patients, showed minimal hepatitis in 17 and mild chronic hepatitis in 16. Infection with HCV genotype Ib was found in 55.5% of patients, with a peak prevalence of 83% in children from southern Italy (P < 0.05 vs other regions). The remaining children were infected with HCV genotype la (16.6%), genotype 2 (11.1%). and mixed (10.9%) or undetermined (2.7%) genotypes. In one patient, HCV viraemia was never detected. There was no statistically significant correlation between genotype and age, sex, source of infection, alanine aminotransferase pattern and histological activity index. These results indicate that genotype 1b is widespread among Italian children with chronic hepatitis C, although with significant geographical variations. It is not associated with a more severe liver disease, therefore suggesting that the greater severity of liver disease recently reported in adults could reflect the cumulative effects of disease duration and of interfering cofactors.     

Primary sclerosing cholangitis (PSC): clinical,laboratory and survival analysis in children and adults

Abstract: Background: Primary sclerosing cholangitis (PSC) is an uncommon disorder, rarely diagnosed in children, moreover, data on its natural history and survival are still lacking. Aim: The study was undertaken to compare clinical, laboratory and survival rates in two series of PSC: one in a pediatric group (group A) and the other in an adult population (group B). Methods: Group A included 9 patients (5 males, 4 females, mean age 10 yrs, range 7–15); group B included 28 patients (19 males, 9 females, mean age 32 years, range 19–60). The mean follow-up was 5.2 years in group A and 6.9 years in group B (range 1–14 years). ERCP and colonos-copy were performed in each case. Survival was analyzed using the Kaplan-Meier method. Results: At presentation children showed significantly higher levels of IgG and AST compared to adults (p<0.05); moreover, interface hepatitis occurred in 50% of children and in 14.2% in adults (p= ns). During follow-up the following major events occurred: oesophageal bleeding (n=2) in group A; progressive liver failure (n=6), cholangiocarcinoma (n=3), colonic cancer (n=1) in group B. Liver transplantation (OLTx) was performed in 4 adults (one died after a retransplantation). No deaths were observed in children. The Kaplan-Meier curve in adults shows a 65% rate of survival at 10 years. Conclusions: The present findings on PSC suggest a more severe activity of the disease in children than in adults at presentation; nonetheless, the prognosis seems to be better in children than in adults. The Mayo score prognostic index does not predict the development of liver/colonic cancer. A poor outcome (defined as death or being listed for OLTx) only occurred in adults.     

Long-term prognosis of patients with extrahepatic biliary atresia successfully treated with surgery. Our experience

The long-term prognosis of extrahepatic biliary atresia after surgical restoration of bile flow is still controversial. An ongoing process of cirrhosis and the development of portal hypertension continue to create frequent and frustrating management problems. Clinical features, hepatic function, echotomography aspect, calcium-phosphorus metabolism and serum levels of 25-OH-D-3 were evaluated in 12 anicteric patients with extrahepatic biliary atresia successfully treated in a period from 1974 through 1987. Seven of these children had a total of 21 episodes of cholangitis. In five patients liver biopsy, obtained at the time of the external diversion closure, showed a biliary cirrhosis. Growth, development and hepatic function were normal in all children studied; one patient had esophageal varices. The serum levels of 25-OH-D3 in patients without oral supplementation of vitamin D are lower than normal. This deficit can be corrected by oral administration of vitamin D. Our study revealed that the children with successful portoenterostomy appeared to thrive normally and that they tolerated the relatively mild liver damage. We believe that Kasai operation should be done in all patients with extrahepatic biliary atresia and that the liver transplantation is to be reserved only in those with unsuccessful Kasai. In our experience external diversion was not useful to prevent cholangitis and moreover it complicates the hepatectomy in case of transplantation.     

Transmission of hepatitis C virus from infected mother to offspring during subsequent pregnancies

BACKGROUND: Several studies have demonstrated that hepatitis C virus (HCV) may be transmitted from mother to offspring. To date, however, little is known about the risk of vertical transmission during subsequent pregnancies. The purpose of this study was to evaluate the risk of vertical HCV transmission in offspring in subsequent pregnancies of HCV infected women. METHODS: In a multicenter study, two groups of index cases were selected. Group 1 included 75 children investigated for HCV infection during prospective studies of vertical transmission. Group 2 included children born to HCV-infected mothers and found to be HCV infected, independent of studies on vertical transmission. All children in the index cases had one or more siblings. Anti-HCV, HCV-RNA (determined by polymerase chain reaction), and HCV genotype were evaluated in all the infected children, their mothers, and siblings. RESULTS: The results indicate that a mother who has already delivered an HCV-infected baby is not at greater risk of infecting her second child. Duration of maternal infection does not seem to be a risk factor in offspring infection, because HCV infection is equally distributed among first-born infants and infants of subsequent births. Because clustering of HCV infection among siblings appeared to be rare in this study, data also indirectly confirm that the risk of horizontal transmission of HCV among siblings is low. CONCLUSION: For practical purposes, the current observations indicate that mothers who have already delivered an HCV-infected child can be advised that this event does not increase the probability of infecting the second child.     

Isolated hepatocyte transplantation for Crigler-Najjar syndrome type 1

Crigler-Najjar syndrome type 1 (CN1) is an inherited disorder characterized by the absence of hepatic uridine diphosphoglucuronate glucuronosyltransferase (UDPGT), the enzyme responsible for the conjugation and excretion of bilirubin. We performed allogenic hepatocyte transplantation (AHT) in a child with CN1, aiming to improve bilirubin glucuronidation in this condition. A 9-year-old boy with CN1 was prepared with plasmapheresis and immunosuppression with prednisolone and tacrolimus. When a graft was made available, 7.5 x 10(9) hepatocytes were isolated and infused into the portal vein percutaneously. After 2 weeks phenobarbitone was added to promote the enzymatic activity of UDPGT of the transplanted hepatocytes. Nocturnal phototherapy was continued throughout the studied period. Total bilirubin was considered a reliable marker of allogenic cell function. There was no significant variation of vital signs nor complications during the infusion. Mean +/- SD bilirubin level was 530 +/- 38 micromol/L before and 359 +/- 46 micromol/L after AHT (t-test, p < 0.001). However, the introduction of phenobarbitone was followed by a drop of tacrolimus level with increase of alanine aminotransferase (ALT) and increase of bilirubin. After standard treatment of cellular rejection bilirubin fell again but from then on it was maintained at a greater level. After discharge the patient experienced a further increase of bilirubin that returned to predischarge levels after readmission to the hospital. This was interpreted as poor compliance with phototherapy. Only partial correction of clinical jaundice and the poor tolerability to nocturnal phototherapy led the parents to refuse further hepatocyte infusions and request an orthotopic liver transplant. After 24 months the child is well, with good liver function on tacrolimus and prednisolone-based immunosuppression. Isolated AHT, though effective and safe, is not sufficient to correct CN1. Maintenance of adequate immunosuppression and family compliance are the main factors hampering the success of this procedure.