Identification and Functional Analysis of APOB Variants in a Cohort of Hypercholesterolemic Patients.

Mutations in APOB are the second most frequent cause of familial hypercholesterolemia (FH). APOB is highly polymorphic, and many variants are benign or of uncertain significance, so functional analysis is necessary to ascertain their pathogenicity. Our aim was to identify and characterize APOB variants in patients with hypercholesterolemia. Index patients (n = 825) with clinically suspected FH were analyzed using next-generation sequencing. In total, 40% of the patients presented a variant in LDLR, APOB, PCSK9 or LDLRAP1, with 12% of the variants in APOB. These variants showed frequencies in the general population lower than 0.5% and were classified as damaging and/or probably damaging by 3 or more predictors of pathogenicity. The variants c.10030A>G;p.(Lys3344Glu) and c.11401T>A;p.(Ser3801Thr) were characterized. The p.(Lys3344Glu) variant co-segregated with high low-density lipoprotein (LDL)-cholesterol in 2 families studied. LDL isolated from apoB p.(Lys3344Glu) heterozygous patients showed reduced ability to compete with fluorescently-labelled LDL for cellular binding and uptake compared with control LDL and was markedly deficient in supporting U937 cell proliferation. LDL that was carrying apoB p.(Ser3801Thr) was not defective in competing with control LDL for cellular binding and uptake. We conclude that the apoB p.(Lys3344Glu) variant is defective in the interaction with the LDL receptor and is causative of FH, whereas the apoB p.(Ser3801Thr) variant is benign.

Serum interleukin-15 levels in cancer patients with cachexia.

Interleukin-15 (IL-15) has important anabolic effects on muscle protein metabolism through a decrease in the ATP-ubiquitin-dependent proteolytic pathway. The role of IL-15 in human cancer cachexia is unknown. The aim of this study was to assess the relationship between interleukin-15 (IL-15) in cancer patients with cachexia at diagnosis of malignancy and 8 weeks later. An observational study of 21 cancer patients (with and without cachexia) and 8 healthy subjects was conducted. Body composition was measured by leg-to-leg impedance. Serum IL-15 levels were assessed at baseline and after 4 and 8 weeks. Baseline IL-15 values were similar in cancer patients and in healthy subjects. Cancer patients with lower baseline levels of IL-15 (<2 pg/ml) had significantly higher fat mass (%) along the study. Eighteen patients completed the study: five patients showed an increase of 3.7 kg at the end of the study (5.4% of body weight) and showed a mean increase of IL-15 of 1.32 pg/ml (121%) at 4 weeks and 2.32 pg/ml (197%) at 8 weeks, as compared with mean decrease of -4.1 kg (-5.3%) and -0.09 pg/ml (-2.5%) and 0.6 pg/ml (40.8%) in the 13 patients who lost weight (P=0.001 and P=0.022, respectively). Changes of IL-15 at 4 and 8 weeks were directly associated with changes in body weight, body mass index (BMI), fat-free mass and muscle mass (P<0.05), and indirectly associated with percentage of weight loss (P<0.05). In summary, although the results indicate that IL-15 does not have a role in cancer cachexia pathogenesis, the association during evolution between serum IL-15 and changes in weight and muscle mass suggests a possible role of IL-15 as a marker of the body composition response in cancer patients who are losing weight at the time of diagnosis.