What’s New in Mass Spec?
Mass spec returns in the clinic with the latest studies on ectopic pregnancy, Parkinson’s Disease, ketamine exposure, and chronic kidney disease
Parkinson's Disease (PD) has become worryingly prevalent – with an estimated 14 million patients projected by 2040. The underlying cellular mechanisms involved, such as the precise role of alpha synuclein (α-syn) protein accumulation, are still poorly understood. To learn more, a Swiss research team combined NanoSIMS and stable isotope labeling to study α-syn aggregation in genetically modified rats that overexpressed human α-syn in one hemisphere of the brain. They found that neurons overexpressing α-syn showed a heightened overall turnover of carbon, suggesting that the accumulation of α-syn may lead to increased metabolic demands on cells.
“This study shows the potential of the NanoSIMS technology to reveal metabolic changes in the brain, with unprecedented resolution, at the subcellular level,” said corresponding author, Bernard Schneider, in the press release.
Farming communities – predominantly in South Asian regions – are tormented by cases of chronic kidney disease of uncertain etiology (CKDu). Based on a popular hypothesis suggesting that herbicide contamination, water hardness, and co-occurring trace elements are causes of CKDu, researchers analyzed water samples from Sri Lanka for the first time using liquid chromatography with tandem mass spectrometry (LC-MS/MS) and inductively coupled plasma-mass spectrometry (ICP-MS). Glyphosate and fluoride were identified in 44 percent and 90 percent of CDKu-endemic wells, respectively – raising concerns about glyphosate exposure worldwide due to its chemical similarity to “forever chemicals”.
“We think of PFAS as being a drinking water contaminant because it’s mobile and persistent. Now we’re realizing that glyphosate may also be quite persistent in hard water areas,” said Lee Ferguson in a press release.
Ketamine effects unveiled
Ketamine is known to produce antidepressant and antisuicidal responses within an hour, and effects can last for days. But little is known about the underlying mechanisms, raising fundamental questions about the biological and clinical promise of ketamine. To find out more, a team of Chinese researchers used liquid chromatography–tandem mass spectrometry (LC–MS/MS) to see how a dose of ketamine affects individual brain receptors. By adjusting the reaction between these receptors and ketamine, researchers can both shorten and lengthen the antidepressant effects in mice. The findings of this study could lead to customized depression treatments for patients.
Towards an ectopic pregnancy test
Ectopic pregnancy is a condition in which the implantation and development of the fertilized ovum occurs outside the uterus, which can lead to maternal mortality and morbidity. Unfortunately, early detection methods are lacking, which is why researchers from Bharathidasan University, India, decided to explore the saliva proteome as a route to a diagnostic test. They used LC-MS/MS to identify 101 proteins that were found to be specific for ruptured ectopic pregnancy. “Intensive investigation on the salivary proteins specific to EP can potentially lead to setting up of a panel of candidate biomarkers and developing a non-invasive protein-based diagnostic kit,” the authors said.
In Other News…
Changi General Hospital, Singapore, begins AI-assisted clinical tests with advanced mass spectrometry to diagnose salt-sensitive and curable forms of hypertension. Link
University Hospital Bonn researchers use LC-MS to decode a gene that blocks sperm maturation in mice when altered – a possible cause of male infertility. Link
Significant PFAS concentrations were found in fish by LC-HRMS, leading the Oregon Health Authority to advise against whole-body consumption of most fish in the Columbia Slough to minimize exposure. Link
High-throughput isotope dilution HPLC-MS/MS method developed for the diagnosis of e-Cigarette/vaping associated lung injury successfully detects cotinine (COT) and trans-3ʹ-hydroxycotinine (HCT) – two residues used as biomarkers to quantify nicotine exposure – with 94.8 percent and 93.6 percent accuracy, respectively. Link
Isabelle Kohler and colleagues compare collision-induced dissociation and electron-activated dissociation (EAD) as fragmentation methods and find that certain EAD exclusive product ions play a significant role in structural elucidation of some metabolites. Link
Researchers detect PFAS in Chinese cosmetic samples, including products marketed for pregnant women; perfluorobutanoic acid, with high placental transfer efficiency, was the major PFAS in cosmetics for pregnant women. Link
Associate Editor, The Analytical Scientist