Simple detection of a point mutation in LDL receptor gene causing familial hypercholesterolemia in southern Italy by allele-specific polymerase chain reaction.

Polymerase chain reaction (PCR) amplification of specific alleles allowed the rapid detection of a point mutation (missense Gly528 → Asp) in exon 11 of the low density lipoprotein receptor gene which was otherwise not detectable by exon amplification and enzymatic digestion as it does not modify the normal restriction pattern. The mutant allele, designated as FH-Palermo-1 from the origin of the first carrier family identified, gave a specific PCR product of 109 bp clearly distinct from the product of 168 bp obtained from other alleles with a nonspecific couple of primers. This method allowed us to distinguish one positive sample mixed with up to 11 parts of normal DNA. Furthermore, the specific amplification product was characterized by a Bsm I restriction site not present in nonspecific products.—Cantafora, A., I. Blotta, E. Mercuri, S. Calandra, and S. Bertolini. Simple detection of a point mutation in LDL receptor gene causing familial hypercholesterolemia in southern Italy by allele-specific polymerase chain reaction. J. Lipid Res. 1998. 39: 1101–1105

Insulin-like growth factor-1 isoforms in rat hepatocytes and cholangiocytes and their involvement in protection against cholestatic injury

A 'locally acting' IGF1 ( insulin- like growth factor 1) isoform has been recently identified in the skeletal muscle and neural tissues where it accelerates injury repair. No information exist on the expression and function of IGF1 isoforms in the liver. We investigated IGF1 isoforms in rat hepatocytes and cholangiocytes and evaluated their involvement in cell proliferation or damage induced by experimental cholestasis ( bile duct ligation, BDL) or hydrophobic bile salts. IGF1 isoforms were analyzed by real- time PCR by using b- actin as internal reference. In both hepatocytes and cholangiocytes, the ` locally acting' IGF1 isoform ( XO6108) and ` circulating' IGF1 isoform ( NM_ 178866) represented respectively 44 and 52% of the total IGF1. Basal mRNAs for both ` locally acting' and ` circulating' IGF1 isoforms were higher ( Po0.05) in hepatocytes than cholangiocytes. After BDL for 3 h, the ` locally acting' IGF1 isoform decreased threefold ( Po0.05) in hepatocytes but remained stable in cholangiocytes with respect to sham- controls. After 1 week of BDL, hepatocytes displayed a further fivefold decrease of ` locally acting' IGF1 mRNA. In contrast, cholangiocytes showed an eightfold increase of the ` locally acting' IGF1 mRNA. The effect of 3 h of BDL on IGF1 isoforms was reproduced in vitro by incubation with glycochenodeoxycholate ( GCDC). The cytotoxic effects ( inhibition of proliferation and induction of apoptosis) of GCDC on isolated cholangiocytes were more pronounced after selective silencing ( SiRNA) of ` locally acting' than ` circulating' IGF1 isoform. Rat hepatocytes and cholangiocytes express the ` locally acting' IGF1 isoform, which decreased during cell damage and increased during cell proliferation. The ` locally acting' IGF1 was more active than the ` circulating' isoform in protecting cholangiocytes from GCDC- induced cytotoxicity. These findings indicate that, besides muscle and neural tissues, also in liver cells the ` locally acting' IGF1 isoform is important in modulating response to damage

Clinical expression of familial hypercholesterolemia in clusters of mutations of the LDL receptor gene that cause a receptor-defective or receptor-negative phenotype

Seventy-one mutations of the low density lipoprotein (LDL) receptor gene were identified in 282 unrelated Italian familial hypercholesterolemia (FH) heterozygotes. By extending genotype analysis to families of the index cases, we identified 12 mutation clusters and localized them in specific areas of Italy. To evaluate the impact of these mutations on the clinical expression of FH, the clusters were separated into 2 groups: receptor-defective and receptor-negative, according to the LDL receptor defect caused by each mutation. These 2 groups were comparable in terms of the patients’ age, sex distribution, body mass index, arterial hypertension, and smoking status. In receptor-negative subjects, LDL cholesterol was higher (118%) and high density lipoprotein cholesterol lower (25%) than the values found in receptor-defective subjects. The prevalence of tendon xanthomas and coronary artery disease (CAD) was 2-fold higher in receptor-negative subjects. In patients >30 years of age in both groups, the presence of CAD was related to age, arterial hypertension, previous smoking, and LDL cholesterol level. Independent contributors to CAD in the receptor-defective subjects were male sex, arterial hypertension, and LDL cholesterol level; in the receptor-negative subjects, the first 2 variables were strong predictors of CAD, whereas the LDL cholesterol level had a lower impact than in receptor-defective subjects. Overall, in receptor-negative subjects, the risk of CAD was 2.6-fold that of receptordefective subjects. Wide interindividual variability in LDL cholesterol levels was found in each cluster. Apolipoprotein E genotype analysis showed a lowering effect of the ε2 allele and a raising effect of the ε4 allele on the LDL cholesterol level in both groups; however, the apolipoprotein E genotype accounted for only 4% of the variation in LDL cholesterol. Haplotype analysis showed that all families of the major clusters shared the same intragenic haplotype cosegregating with the mutation, thus suggesting the presence of common ancestors

Differential vascular endothelial growth factor A protein expression between small hepatocellular carcinoma and cirrhosis correlates with serum vascular endothelial growth factor A and alpha-fetoprotein.

Drugs with antivascular endothelial growth factor A (anti-VEGF-A) action are under clinical evaluation with encouraging results in advanced hepatocellular carcinoma (HCC). The relative VEGF-A protein expression in non-advanced HCC and in the cirrhotic non-tumoral tissue in the same patient, a variable that could be important for treatment efficacy, has been investigated with conflicting results, only using the cirrhotic tissue surrounding the neoplasm (CS). We measured, for the first time, VEGF-A expression in non-advanced HCC and in the respective CS and cirrhotic tissue at a distance from the tumour (CD), in 24 patients who underwent liver transplantation. VEGF-A protein was more expressed (P<0.05) in HCC than in CD, while no difference was found between HCC and CS. In HCC patients with a serum alpha-fetoprotein (AFP) higher than 20 ng/ml, VEGF-A protein expression in HCC was higher than in the corresponding CD in 83% of cases and AFP and serum VEGF-A corrected for the platelet count positively correlated with the differential VEGF-A protein expression between HCC and CD. Our data provide a rationale for clinical trials involving anti-VEGF-A treatments in patients with non-advanced HCC, and suggest that serum AFP and VEGF-A are variables to be taken into account in these studies