In this regard, we recently demonstrated that Tat causes neuronal deregulation by increasing the levels of secreted calcium, mitochondria deregulation and axonal transport alteration (manuscript in preparation).
The lack of evidence supporting an association between fasting glucose level and DepS in the present study accords with these previous studies and suggests that the process linking T2D to depression may not involve a direct path between hyperglycemia and related glucose transport alteration and depression risk.
Increased sympathetic nervous system activity, altered interstitial ion transport, alterations in endothelial permeability, and peroxisome proliferator-activated receptor-γ-mediated expression of vascular permeability growth factor represent other possible mechanisms for oedema with these agents 11.
The presence of lactate within pilocytic tumours might be explained by several mechanisms, such as an abnormal number or dysfunction of mitochondria (which would interfere with the processes of oxidative phosphorylation and electron transport); alterations in proportional oxygen delivery, oxygen extraction, or oxygen usage by the tumour; or anaerobic glycolysis by tumour cells [23, 24].
Surprisingly, axon myelination was affected in our mutant mice, and axonal transport alterations were observed in Drosophila.
Other early alterations includes intracellular signaling defects, axonal transport alterations, deregulated autophagy, alteration of synaptic function, defects in brain derived neurotrophic factor transcription, secretion and transport (3), perturbation of calcium homeostasis (6) and mitochondrial defects (7, 8).
Thus the amino acid transport alterations related to diet supplementation with different amino acids might involve specific effects on transporters, especially when associated with neoplastic growth.
While this report was in preparation, another group recently reported axonal transport alterations in one neuronal culture from a single-SPG4 patient when compared with one control culture (29).
The acquired resistance to apoptosis induced by MTX in SCC-9 cells might not be attributed to MTX transport alterations, because we detected a transient increase in SCC-9 cell growth after culturing for 48 h with increasing doses of MTX.
Among the many factors that have been involved in the mechanisms of MN degeneration are glutamate receptor-mediated excitotoxicity, oxidative stress, mitochondrial dysfunction, neuroinflammation, immune-mediated processes, protein aggregation and axonal transport alterations [ 1, 2], but there is still no satisfactory explanation of why such factors damage predominantly MNs.
The differential mechanism of regulation of Na-glutamine co-transport in crypt as compared to villus, specifically, altered affinity of SN2/SNAT5 during chronic intestinal inflammation suggests that a specific immune inflammatory mediator/pathway might be responsible for each Na-glutamine co-transport alteration [ 29].
