Exploring Metabolic Configurations of Single Cells within Complex Tissue Microenvironments.

Over the past years, plenty of evidence has emerged illustrating how metabolism supports many aspects of cellular function and how metabolic reprogramming can drive cell differentiation and fate. Here, we present a method to assess the metabolic configuration of single cells within their native tissue microenvironment via the visualization and quantification of multiple enzymatic activities measured at saturating substrate conditions combined with subsequent cell type identification. After careful validation of the approach and to demonstrate its potential, we assessed the intracellular metabolic configuration of different human immune cell populations in healthy and tumor colon tissue. Additionally, we analyzed the intercellular metabolic relationship between cancer cells and cancer-associated fibroblasts in a breast cancer tissue array. This study demonstrates that the determination of metabolic configurations in single cells could be a powerful complementary tool for every researcher interested to study metabolic networks in situ.

The effect of storage temperature fluctuations on the stability of biochemical analytes in blood serum.

BACKGROUND: Irreproducibility of scientific results constitutes an undesirably onerous economic burden and is in many cases caused by low-quality materials. Therefore, researchers are increasingly devoting their attention to the bioresources they use. In turn, those bioresources are required to validate their preanalytical processes in order to ensure best possible quality. The present study thus aimed to evaluate the impact of repeated temperature fluctuations, as they occur in most research biobanks due to repetitive opening and closing of freezer doors, on the stability of 26 biochemical analytes. METHODS: Serum of 43 individuals was randomly assigned to a fluctuation (n=21) and a control group (n=22). Serum of the fluctuation group underwent controlled temperature fluctuations (30 fluctuations <-75°C - <-65°C - <-75°C under real-life freezer conditions within 21 days). Control sera were stored at constant conditions. After 10, 20, and 30 fluctuations, results derived from the fluctuation group were compared to baseline and to the control group by means of general linear models. RESULTS: Sixteen biomarkers showed statistically significant changes over time, whereas only seven of those presented with diagnostically/clinically relevant changes at certain time points (aspartate aminotransferase, amylase, calcium, uric acid, creatinine, inorganic phosphate and total protein). However, there was no difference between the fluctuation and the control group. CONCLUSIONS: Some serum analytes are influenced by storage, even at temperatures as low as <-70°C. In contrast, we found no evidence that complex temperature fluctuations produced by storage of and access to biospecimens in biobank freezers generate any additional variability.

Identification of a homozygous PSTPIP1 mutation in a patient with a PAPA-like syndrome responding to canakinumab treatment.

BACKGROUND: Pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome (OMIM 604416) is a rare autosomal dominant inherited autoinflammatory syndrome characterized by pyogenic sterile arthritis and less frequently accompanied by pyoderma gangrenosum and acne. It is associated with dominant missense mutations in the proline-serine-threonine phosphatase-interacting protein 1 gene (PSTPIP1) located on chromosome 15. The patient was diagnosed as having features of a PAPA-like syndrome in which cutaneous manifestations, such as pyoderma gangrenosum and acne fulminans, predominated. OBSERVATIONS: Sequencing of the PSTPIP1 gene was performed in the patient and his extended family. The patient's DNA analysis revealed a homozygous nucleotide exchange c.773G>C in the PSTPIP1 gene, leading to the substitution of glycine 258 by alanine (p.Gly258Ala), a previously reported heterozygous polymorphism. Heterozygous changes were identified in both of the patient's parents and in 7 other family members, all of whom were asymptomatic. The patient was treated with canakinumab, a human anti-interleukin 1ß monoclonal antibody, which led to rapid remission of the symptoms. CONCLUSIONS: To our knowledge, this is the first reported case of the resolution of dermatological symptoms associated with a PAPA-like syndrome using canakinumab treatment. Further study of the p.Gly258Ala variant is warranted to determine whether this mutation has a role in causing an apparently recessive cutaneous syndrome resembling PAPA syndrome.

The effect of p22-PHOX (CYBA) polymorphisms on premature coronary artery disease (≤ 40 years of age).

Acute myocardial infarction at a young age is associated with high morbidity and long-term mortality. The NADPH oxidase system as a main source of reactive oxygen species in vascular cells has been implicated in development and progression of coronary artery disease (CAD). In our study, we investigated the effect of polymorphisms in the p22-PHOX (CYBA) gene on CAD in young patients (≤ 40 years). We prospectively recruited 302 subjects into our multi-centre case control study, including 102 young myocardial infarction patients (≤ 40 years) from two high-volume cardiac catheterisation hospitals and frequency-matched them on age, gender, and center to 200 hospital controls in an approximate 2:1 ratio per case patient. The homozygote c.-930A>G promoter polymorphism was significantly more prevalent in the controls than in the infarction patients. In the adjusted logistic regression analysis, we detected a protective effect of the c.-930A>G promoter polymorphism against premature myocardial infarction. Using a log-additive/per-allele model, we detected an unadjusted odds ratio (OR) of 0.63 (95% confidence interval [CI] 0.45-0.9, p-value 0.011). In the adjusted model the association was more pronounced with an OR of 0.5 (95% CI 0.3-0.81, p-value 0.005). The C242T polymorphism and the 640A>G polymorphism did not differ significantly between the study groups. Furthermore we could not detect a significant effect for these polymorphisms in the logistic regression analysis. The present study suggests a protective association between the c.-930A>G promoter polymorphism in the p22-PHOX (CYBA) gene and the development of myocardial infarction in young individuals (≤ 40 years).