Novel mutations in the GPIHBP1 gene identified in 2 patients with recurrent acute pancreatitis.

BACKGROUND: Glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) has been demonstrated to be essential for the in vivo function of lipoprotein lipase (LPL), the major triglyceride (TG)-hydrolyzing enzyme involved in the intravascular lipolysis of TG-rich lipoproteins. Recently, loss-of-function mutations of GPIHBP1 have been reported as the cause of type I hyperlipoproteinemia in several patients. METHODS: Two unrelated patients were referred to our Lipid Units because of a severe hypertriglyceridemia and recurrent pancreatitis. We measured LPL activity in postheparin plasma and serum ApoCII and sequenced LPL, APOC2, and GPIHBP1. RESULTS: The 2 patients exhibited very low LPL activity not associated with mutations in LPL gene or with ApoCII deficiency. The sequence of GPIHBP1 revealed 2 novel point mutations. One patient (proband 1) was found to be homozygous for a C>A transversion in exon 3 resulting in the conversion of threonine to lysine at position 80 (p.Thr80Lys). The other patient (proband 2) was found to be homozygous for a G>T transversion in the third base of the ATG translation initiation codon in exon 1, resulting in the conversion of methionine to isoleucine (p.Met1Ile). CONCLUSION: In conclusion, we have identified 2 novel GPIHBP1 missense mutations in 2 unrelated patients as the cause of their severe hypertriglyceridemia.

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.