The HFE gene heterozygosis H63D: a cofactor for liver damage in patients with steatohepatitis? Epidemiological and clinical considerations.

BACKGROUND: The altered status of iron metabolism is reported in hereditary haemochromatosis and in non-alcoholic liver fatty disease. We investigated the relation between the H63D HFE mutation gene and non-alcoholic steatohepatitis (NASH). METHODS: We studied as outpatients, 272 Italian persons with NASH and compared them with 430 healthy subjects. Genetic screening for haemochromatosis, haematochemical tests, liver ultrasound examination and liver biopsies were carried out. RESULTS: The prevalence of heterozygosity for the H63D mutation in NASH patients was not significantly greater than controls. In assessing the C282Y HFE gene mutation alone, the percentage of heterozygosis for C282Y was not different in subjects with NASH compared with controls. As regards a mutation C282Y/H63D there was no significant difference between the two groups. The mean fibrosis score was not significantly different between subjects of group A, with and without HFE mutations (1 +/- 8 and 1 +/- 9, respectively); we did not find a significant correlation between hepatic iron concentration and histological score between subjects. CONCLUSION: We have not found a significantly increased prevalence of the mutation H63D in the HFE gene in our patients with NASH. In these patients there was no more severe hepatic histological score when compared with NASH subjects without HFE mutations.

[Heterozygosis H63D in patients with steatohepatitis and chronic hepatitis C]. / Eterozigosi H63D per emocromatosi in pazienti affetti da steatoepatite e epatite cronica da virus C.

OBJECTIVE: Classic hereditary hemochromatosis is an autosomal recessive iron-overload disorder associated with mutation of the HFE gene. The homozygous genetic defect predisposes to a chain of events that may culminate in severe damage in multiple organs. Pathologic implications of heterozygous defect are still questionable; in fact since these individuals may have slight increases in intra-cellular iron, it has been questioned whether this would enhance damage from other diseases. We investigated whether steatohepatitis and chronic hepatitis C can be worsened by heterozygosis for C282Y and H63D. PATIENTS AND METHODS: We investigated 216 subjects with Steatohepatitis and/or chronic hepatitis C diagnosed by ultrasonography and liver biopsy with histological assessment compared with 110 healthy subjects. In all subjects we performed Saturated Transferrine, Plasma Ferritin and the research of HFE mutation by a Real Time Method. A statistical analysis was performed. RESULTS: A H63D mutation was present in 32/108 patients with Steatohepatitis, in 30/108 patients with chronic hepatitis C and in 22/110 healthy subjects. A C282Y mutation was present in 2/108 patients with chronic hepatitis C, in 4/108 with steatohepatitis and in 2/108 healthy subjects. No significant difference was present about incidence of this mutation between pathological and healthy subjects. No significant differences have observed between pathological groups and normal group about the degree of histological damage. CONCLUSIONS: Our study revealed that steatohepatitis and chronic hepatitis C cannot be worsened by heterozygosis for C282Y and H63D.

Noninvasive prenatal diagnosis of chromosomal aneuploidies by isolation and analysis of fetal cells from maternal blood.

The isolation and analysis of nucleated fetal cells (NFCs) from maternal blood may represent a new approach to noninvasive prenatal diagnosis. Although promising, these techniques require highly accurate separation of NFCs from nucleated cells of maternal origin; the two major problems limiting these techniques are the relative rarity of fetal cells in maternal blood and the need to establish their fetal origin. We now report a novel procedure that has allowed accurate separation of NFCs from maternal cells. The technique reported involves direct micromanipulator isolation of histochemically identified hemoglobin F-positive nucleated cells to obtain fetal nucleated red blood cells (FNRBCs) of high yield and purity. Using this technique, followed by cell-by-cell multicolor fluorescence in situ hybridization (FISH) analysis of purified FNRBCs, we were able to detect some of the most common human aneuploidies (including Down syndrome, Klinefelter syndrome, and trisomy 13) in 33 pregnant women referred for amniocentesis. The procedure used, which can be completed in <72 hrs, produced complete concordance with the results of amniocentesis. We also confirm findings of prior studies suggesting that the number of FNRBCs in maternal circulation is remarkably higher in abnormal pregnancies than in normal pregnancies, especially in women carrying a fetus with trisomy 21.

Molecular cloning of trkE, a novel trk-related putative tyrosine kinase receptor isolated from normal human keratinocytes and widely expressed by normal human tissues.

We have identified and cloned a new member of the trk gene family, termed trkE, which generates a 3.9-kilobase (kb) transcript in normal human keratinocytes and in a variety of normal human tissues, but not in liver. Albeit at low level, trkE transcript is expressed also by PC12 cells. The open reading frame codes for a polypeptide of 876 amino acids exhibiting the classic features of cell surface tyrosine protein kinases. trkE catalytic domain is 41% identical to trkA and shows several features unique to the trk gene family. Its extracellular domain does not show significant homology to any known proteins. trkE is the first member of this gene family found abundantly and widely expressed in normal human tissues. Several lines of evidence suggest that NGF is also the ligand for trkE; (i) normal human keratinocytes bind NGF with high affinity, (ii) NGF stimulates keratinocyte growth in an autocrine fashion, (iii) NGF exerts its biological effect on keratinocytes through the stimulation of a trk-specific tyrosine kinase, and (iv) keratinocytes lack trkA but do express large amount of trkE. trkE might also be the NGF receptor by other human peripheral tissues, such as pancreatic islets, and might represent a non-neuronal receptor for this ligand.

Nerve growth factor binds to normal human keratinocytes through high and low affinity receptors and stimulates their growth by a novel autocrine loop.

Normal human keratinocytes synthesize and secrete biologically active nerve growth factor (NGF) in a growth regulated fashion (Di Marco, E., Marchisio, P. C., Bondanza, S., Franzi, A. T., Cancedda, R., and De Luca, M. (1991) J. Biol. Chem. 266, 21718-21722). Here we show that the same human keratinocytes bind NGF via low and high affinity receptors. In parallel with the course of NGF synthesis, the expression of low affinity NGF receptor (p75NGFr) decreases when a confluent, differentiated, and fully stratified epithelium is obtained. In skin sections, p75NGFr is present in basal keratinocytes and absent from suprabasal, terminally differentiated cells. The trkA protooncogene product (p140trkA), a component of the NGF receptor, is not expressed by keratinocytes. Instead, keratinocytes express a new member of the trk family (that we termed trkE), which generates 3.9-kilobase transcripts. Keratinocyte-derived NGF plays a key role in the autocrine epidermal cell proliferation. This has been proven by (i) direct effect of NGF on [3H]thymidine incorporation, (ii) inhibition of autocrine keratinocyte growth by monoclonal antibodies (alpha D11) inhibiting human NGF biological activity, and (iii) inhibition of autocrine keratinocyte proliferation by a trk-specific inhibitor, the natural alkaloid K252a. These data provide evidence that NGF, in addition to its effect as a survival and differentiation factor, is a potent regulator of cell proliferation, at least in human epithelial cells.