Elevated plasma glutamate levels in colorectal carcinoma patients and in patients with acquired immunodeficiency syndrome (AIDS)

Exciting Times beyond the Brain: Metabotropic Glutamate Receptors in Peripheral and Non-Neural Tissues

“…Plasma levels of L-glutamate are generally elevated in patients with carcinoma (Dröge et al, 1987) and seem to correlate with an impairment in immune function. Furthermore, tumor cells show decreased motility and invasiveness upon administration of ionotropic glutamate receptor antagonists (Rzeski et al, 2001).…”

The potential role of glutamate in the current diabetes epidemic

“…Hyperglutamatemia has been found in obesity [131], liver diseases [132,133], cancer, and HIV infection [134][135][136] even in the absence of symptoms of acquired immunodeficiency syndrome [136,137]. In cancer and HIV-infected persons, the increase in plasma glutamate has been related to the metabolic properties of the tumors combined with an altered glutamate metabolism [138].…”

“…In cancer and HIV-infected persons, the increase in plasma glutamate has been related to the metabolic properties of the tumors combined with an altered glutamate metabolism [138]. Interestingly, in both these conditions, increased glutamate levels are inversely correlated with lymphocytic activity [136] and hyperglutamatemia has been implicated in the pathogenesis of immunosuppression [136][137][138]. Hyperglutamatemia is common in neurodegenerative diseases and in particular in stroke patients [139][140][141] where it has been ascribed to an increased release of glutamate by the activated platelets [139,140].…”

“…The impaired BBB function might increase the load of glutamate in the CNS [185] and worsen neurotoxicity that, in turn, might increase plasma glutamate levels [139][140][141][142][143][144][145][146][147]. Hyperglutamatemia affects the immune system [136][137][138]186] and might also exert a suppressive function on regulatory T cells as glutamate decreases Interleukin-10 secretion by peripheral blood lymphocytes of subjects with autoimmune thyroiditis [187]. One potential pathway linking high glutamate with the increased risk of diabetes is the enhanced susceptibility of pancreatic b-cells to increased oxidative damage [188], which is an alternative mechanism of glutamate-induced cytotoxicity [39,189].…”

Potentiation of excitotoxicity in HIV-1-associated Dementia and the significance of glutaminase

“…However, high concentrations of extracellular glutamate are known to induce neuronal damage (24)(25)(26)(27). HIV-1-infected patients have been reported to have significantly higher plasma concentrations of glutamate as compared to uninfected controls (28,29). HIV-1 infected macrophages appear to be an important source of extracellular glutamate (20), this glutamate production has recently been linked to the activity of phosphate-activated mitochondrial glutaminase (30).…”