Objective:To investigate mitophagy in 5 patients with severe dominantly inherited optic atrophy (DOA), caused by depletion of OPA1 (a protein that is essential for mitochondrial fusion), compared with healthy controls.Methods:Patients with severe DOA (DOA plus) had peripheral neuropathy, cognitive regression, and epilepsy in addition to loss of vision. We quantified mitophagy in dermal fibroblasts, using 2 high throughput imaging systems, by visualizing colocalization of mitochondrial fragments with engulfing autophagosomes.Results:Fibroblasts from 3 biallelic OPA1(−/−) patients with severe DOA had increased mitochondrial fragmentation and mitochondrial DNA (mtDNA)–depleted cells due to decreased levels of OPA1 protein. Similarly, in siRNA-treated control fibroblasts, profound OPA1 knockdown caused mitochondrial fragmentation, loss of mtDNA, impaired mitochondrial function, and mitochondrial mislocalization. Compared to controls, basal mitophagy (abundance of autophagosomes colocalizing with mitochondria) was increased in (1) biallelic patients, (2) monoallelic patients with DOA plus, and (3) OPA1 siRNA–treated control cultures. Mitophagic flux was also increased. Genetic knockdown of the mitophagy protein ATG7 confirmed this by eliminating differences between patient and control fibroblasts.Conclusions:We demonstrated increased mitophagy and excessive mitochondrial fragmentation in primary human cultures associated with DOA plus due to biallelic OPA1 mutations. We previously found that increased mitophagy (mitochondrial recycling) was associated with visual loss in another mitochondrial optic neuropathy, Leber hereditary optic neuropathy (LHON). Combined with our LHON findings, this implicates excessive mitochondrial fragmentation, dysregulated mitophagy, and impaired response to energetic stress in the pathogenesis of mitochondrial optic neuropathies, potentially linked with mitochondrial mislocalization and mtDNA depletion.
Gamma knife surgery was effective in controlling the growth of residual NPA after previously performed maximal surgical debulking. The major advantage of GKS compared with fractionated radiotherapy seems to be a lower risk of side effects, especially a lower risk of hypopituitarism.
The objective of the study was to evaluate the preoperative visual field defect, the postoperative outcome and the possible prognostic factors in patients with pituitary macroadenoma, using a quantitative method (the mean deviation = MD), and to review the literature. A total of 73 patients, operated trough trans-sphenoidal approach, were selected, and data in single eyes were analysed by calculating the frequency and the degree of postoperative improvement (relative improvement). The visual field defect improved in 95.7% of eyes: The recovery was complete in 48.9% and partial in 46.8%. Multivariate logistic regression showed that factors, independently predictive for complete recovery, were as follows: low preoperative MD absolute value (p = 0.008), low cranio-caudal diameter of tumour (p = 0.02) and young age (p = 0.0001). The mean relative improvement in visual field defect (dMD%) was correlated with the preoperative visual acuity (p = 0.0001) and inversely related with the preoperative MD (p = 0.007) and the age (p = 0.017). The relative improvement was higher in tumours with a smaller cranio-caudal diameter (p = 0.0185). In conclusion, using a quantitative method, we can measure the degree of the postoperative visual field defect improvement. Predictive factors for a complete recovery were good preoperative visual function, young age and low cranio-caudal tumour.
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