Comprehensive characterization of complex glycosphingolipids in human pancreatic cancer tissues

Pancreatic ductal adenocarcinoma (PDAC) is one of the most common causes of cancer-related deaths worldwide, accounting for 90% of primary pancreatic tumors with an average 5-year survival rate of less than 10%. PDAC exhibits aggressive biology, which, together with late detection, results in most PDAC patients presenting with unresectable, locally advanced, or metastatic disease. In-depth lipid profiling and screening of potential biomarkers currently appear to be a promising approach for early detection of PDAC or other cancers. Here, we isolated and characterized complex glycosphingolipids (GSL) from normal and tumor pancreatic tissues of patients with PDAC using a combination of TLC, chemical staining, carbohydrate-recognized ligand-binding assay, and LC/ESI-MS². The major neutral GSL identified were GSL with the terminal blood groups A, B, H, Le^a, Le^b, Le^x, Le^y, P1, and PX2 determinants together with globo- (Gb₃ and Gb₄) and neolacto-series GSL (nLc₄ and nLc₆). We also revealed that the neutral GSL profiles and their relative amounts differ between normal and tumor tissues. Additionally, the normal and tumor pancreatic tissues differ in type 1/2 core chains. Sulfatides and GM₃ gangliosides were the predominant acidic GSL along with the minor sialyl-nLc₄/nLc₆ and sialyl-Le^a/Le^x. The comprehensive analysis of GSL in human PDAC tissues extends the GSL coverage and provides an important platform for further studies of GSL alterations; therefore, it could contribute to the development of new biomarkers and therapeutic approaches.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2017-2018

This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2018. Also included are papers that describe methods appropriate to glycan and glycoprotein analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, new methods, matrices, derivatization, MALDI imaging, fragmentation and the use of arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Most of the applications are presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and highlights the impact that MALDI imaging is having across a range of diciplines. MALDI is still an ideal technique for carbohydrate analysis and advancements in the technique and the range of applications continue steady progress.

Fabry disease with acute myocardial infarction, left ventricular thrombosis, and pericardial effusion: A case report

RATIONALE

Fabry disease (FD) is a rare, X-linked lysosomal deposition disease characterized by multi-system symptoms. The accumulation of globotriaosylceramide in various organs, such as the kidneys and heart, as well as the nervous system, has been speculated to be the mechanism involved in tissue damage, including vascular impairment with thrombotic events.

PATIENT CONCERNS

Here, we describe a 72-year-old male patient diagnosed with FD, who first presented with acute myocardial infarction, left ventricular thrombosis, and pericardial effusion, accompanied by cardiac hypertrophy.

DIAGNOSES

A physical examination showed that he was hemodynamically stable and an electrocardiogram showed ventricular tachycardia (Fig. 1A). The single obvious abnormality was an ST segment depression with a preterminal negative T wave in leads I and aVL (Fig. 1B). Coronary angiography revealed regular findings (Fig. 2). Echocardiogram conducted at our hospital revealed hypertrophy, ejection fraction 40%, pericardial effusion (Fig. 3). Speckle tracking two-dimensional echocardiography strain analysis technology confirmed left ventricular thrombosis, and also revealed decreased movement of the inferior and posterior walls, the basal segment of the posterior wall was locally fibrotic (Fig. 4A and B). Further, myocardial contrast echocardiography confirmed left ventricular thrombosis (Fig. 4C). Cardiovascular magnetic resonance imaging indicated biventricular uneven hypertrophy, which was considered metabolic cardiomyopathy, with diffuse fibrosis of biventricular walls, apical thrombosis, and ischemic cardiomyopathy in the basal segment of the left ventricular lateral wall and left ventricular anterior wall (Fig. 5). Serum alpha-galactosidase concentration was 0.7 nmol/h/mgPr (normal range, 29.0-64.4 nmol/h/mgPr). Subsequent genetic testing revealed that he was hemizygous for a previously reported missense mutation (c.902G>A) inexon 6 of the GLA gene,[1] which induce p.R301Q (p.Arg301Gln), confirming a diagnosis of FD (Fig. 6).

INTERVENTIONS

Orally administered drugs included rivaroxaban, sacubitril valsartan, beta blockers, dapagliflozin, and mineralocorticoid receptor antagonist. Cardiac resynchronization therapy with an implanted defibrillator was implemented to prevent sudden death.

OUTCOMES

At present, he is still in follow-up and there have been no adverse events.

CONCLUSION

Our case suggests that clinicians should consider the possibility of FD in patients with acute myocardial infarction and cardiomyopathy. A detailed analysis of subtle historical clues would help promote earlier diagnosis of FD.

Multicenter evaluation of use of dried blood spot compared to conventional plasma in measurements of globotriaosylsphingosine (LysoGb3) concentration in 104 Fabry patients

OBJECTIVES

Fabry disease (FD) is an X-linked lysosomal storage disorder, resulting from a deficiency of the enzyme α-galactosidase A, responsible for breaking down glycolipids such as globotriaosylceramide and its deacylated derivative, globotriaosylsphingosine (LysoGb3). Here, we compare the levels of LysoGb3 in dried blood spots (DBS) and plasma in patients with classic and late-onset phenotypes.

METHODS

LysoGb3 measurements were performed in 104 FD patients, 39 males and 65 females. Venous blood was collected. A portion was spotted onto filter paper and another portion separated to obtain plasma. The LysoGb3 concentrations in DBS and plasma were determined by highly sensitive electrospray ionization liquid chromatography tandem mass spectrometry. Agreement between different matrices was assessed using linear regression and Bland Altman analysis.

RESULTS

The method on DBS was validated by evaluating its precision, accuracy, matrix effect, recovery, and stability. The analytical performances were verified by comparison of a total of 104 paired DBS and plasma samples from as many FD patients (representing 46 GLA variants). There was a strong correlation between plasma and the corresponding DBS LysoGb3 concentrations, with few exceptions. Discrepancies were observed in anemic patients with typically low hematocrit levels compared to the normal range.

CONCLUSIONS

The method proved to be efficient for the rapid analysis of LysoGb3. DBS provides a convenient, sensitive, and reproducible method for measuring LysoGb3 levels for diagnosis, initial phenotypic assignment, and therapeutic monitoring in patients with FD.

Screening for galactosemia: is there a place for it?

Galactose is a hexose essential for production of energy, which has a prebiotic role and is essential for galactosylation of endogenous and exogenous proteins, ceramides, myelin sheath metabolism and others. The inability to metabolize galactose results in galactosemia. Galactosemia is an autosomal recessive disorder that affects newborns who are born asymptomatic, apparently well and healthy, then develop serious morbidity and mortality upon consuming milk that contains galactose. Those with galactosemia have a deficiency of an enzyme: classic galactosemia (type 1) results from severe deficiency of galactose-1-uridylyltransferase, while galactosemia type II results from galactokinase deficiency and type III results from galactose epimerase deficiency. Many countries include neonatal screening for galactosemia in their national newborn screening program; however, others do not, as the condition is rather rare, with an incidence of 1:30,000-1:100,000, and screening may be seen as not cost-effective and logistically demanding. Early detection and intervention by restricting galactose is not curative but is very rewarding, as it prevents deaths, mental retardation, liver cell failure, renal tubular acidosis and neurological sequelae, and may lead to resolution of cataract formation. Hence, national newborn screening for galactosemia prevents serious potential life-long suffering, morbidity and mortality. Recent advances in communication and biotechnology promise facilitation of logistics of neonatal screening, including improved cost-effectiveness.