Blood thiamine pyrophosphate concentration and its correlation with the stage of diabetic retinopathy.

PURPOSE: To assess the possible relationship between blood thiamine pyrophosphate (TPP) concentration and stage of diabetic retinopathy (DR). METHODS: This comparative cross-sectional study included 80 patients with type 2 diabetes mellitus (T2DM) and 20 age- and gender-matched healthy controls. Diabetic patients were subclassified into four groups each consisting of 20 subjects: no DR, mild-moderate non-proliferative DR (mild-moderate NPDR), severe NPDR, and proliferative DR (PDR). Blood TPP concentration was assessed with high-performance liquid chromatography (HPLC) assay and was correlated with the stage of DR. RESULTS: Mean blood TPP concentration was 80.2 ± 14.8 nmol/L in control group. It was, respectively, 69.85 ± 18.1, 64.95 ± 13.4, 61.9 ± 13.4 and 60.75 ± 14.3 nmol/L in no DR, mild-moderate NPDR, severe NPDR and PDR groups. For mild-moderate NPDR, severe NPDR and PDR groups, TPP concentrations were significantly lower compared with controls (p: 0.014, 0.002, 0.001, respectively). Mean TPP concentration for NPDR patients was higher than for PDR patients, but the difference was not significant (p: 0.478). ANOVA revealed a significant difference between TPP concentrations of groups (p: 0.001). Mean TPP concentration decreased with the stage of DR, and number of patients with thiamine deficiency increased gradually with the stage of DR. A negative correlation was found between the TPP level and occurrence of DR (p: 0.000). CONCLUSION: The results suggest that lower blood TPP concentrations were associated with higher risk of DR. Thiamine might play an important role in the pathophysiology and progression of DR. Thiamine and its derivatives might represent an approach to the prevention and/or treatment of early DR.

Carvacrol Protects Against Paclitaxel-Induced Retinal and Optic Nerve Cytotoxicity: A Histopathological Study.

OBJECTIVES: Carvacrol (CV) is a phenolic monoterpenoid found in the essential oil of a number of aromatic plants and herbs. The present study was an investigation of the potential protective effect of CV against paclitaxel (PTX)-induced retinal and optic nerve cytotoxicity in rats. METHODS: A total of 18 adult male Wistar albino rats (250-400g) were randomized into 3 equal groups comprising 6 animals each. Group 1 (control group) received intraperitoneal (IP) saline solution (0.5 mL/200 g) weekly for 4 weeks. Group 2 received an IP dose of PTX (5 mg/kg), and Group 3 received CV (25 mg/kg) 30 minutes after an IP dose of PTX (5 mg/kg) weekly for 4 weeks. At the conclusion of the experimental period, the retinal and optic nerve tissues of the subjects were evaluated histopathologically. RESULTS: All of the retinal specimens in Group 1 (control) were histopathologically normal. In Group 2 (PTX), all of the eyes (6/6) revealed increased retinal vascularity and rosette-like structures in the outer nuclear layer, and in Group 3 (PTX-CV), all of the eyes (6/6) demonstrated normal retinal vascularity and the absence of rosette-like structures. All of the optic nerve specimens in Group 1 (control) were histopathologically normal. In Group 2 (PTX), all of the eyes (6/6) demonstrated severe vacuolization and a decreased number of astrocytes and oligodendrocytes in the optic nerve specimens, while 3 eyes (3/6) showed marked single cell necrosis. None of the eyes in Group 3 (PTX-CV) demonstrated either vacuolization or a reduction in the number of astrocytes and oligodendrocytes. No remarkable single cell necrosis was observed in the optic nerve specimens of Group 3 (PTX-CV). CONCLUSION: The histopathological findings indicated that CV played a protective role against PTX-induced cytotoxicity. CV might be a promising resource to counteract oxidative stress-based cytotoxicity in the field of retinal and optic nerve disorders.

Carvone protects against paclitaxel-induced retinal and optic nerve cytotoxicity: a histopathological study.

Purpose: Carvone (CVN) is a natural monoterpene found in essential oils of many aromatic plant species. In this study, we investigated the protective effect of CVN against paclitaxel (PTX)-induced retinal and optic nerve cytotoxicity in rats. Methods: Twenty-four male adult Wistar albino rats (250-400 g) were randomized into four equal groups comprising six animals in each. Group 1 (control group) received intraperitoneal (i.p.) saline solution (0.5 mL/200 g) weekly for 4 weeks. Group 2 received i.p. CVN [(S)-(+)- CVN, (5S)-5-Isopropenyl-2-methyl-2-cyclohexen-1-one, C10H14, 25 mg/kg], while Group 3 received i.p. PTX (5 mg/kg) weekly for 4 weeks. Group 4 received i.p. CVN (25 mg/kg) 30 min after i.p. PTX (5 mg/kg) weekly for 4 weeks. At the end of the experimental period, retinal and optic nerve tissues were evaluated histopathologically. Results: All retinal specimens in control and CVN groups were histopathologically normal. In PTX group all eyes (6/6) demonstrated increased retinal vascularity and rosette-like structures in the outer nuclear layer, while in PTX-CVN group all eyes (6/6) demonstrated normal retinal vascularity and absence of rosette-like structures. All optic nerve specimens in control and CVN groups were histopathologically normal. In PTX group all eyes (6/6) demonstrated severe vacuolization and decrease in the number of astrocytes and oligodendrocytes, while 3 eyes (3/6) demonstrated marked single cell necrosis. In PTX-CVN group, 4 eyes (4/6) demonstrated moderate vacuolization while, 2 eyes (2/6) had none. Compared with PTX group, 1 eye (1/6) in PTX-CVN group demonstrated a decrease in numbers of astrocytes and oligodendrocytes while 5 eyes (5/6) were normal. No remarkable single cell necrosis was observed in PTX-CVN group. Conclusions: Our histopathological findings demonstrated the potential protective role of CVN against PTX-induced retinal and optic nerve cytotoxicity. CVN might be a promising molecule in counteracting oxidative stress-based cytotoxicity in the field of retinal and optic nerve disorders.

An important cause of dyspnea after coronary artery bypass grafting: phrenic nerve paralysis.

Diaphragmatic paralysis (DP) due to phrenic nerve paralysis is a rare complication after cardiac surgery. A 48-year-old male patient developed respiratory insufficiency, tachypnea, sinus tachycardia, chest pain, pneumonia, and fever immediately after coronary artery bypass grafting. Paradoxical movement of the epigastrium was noted during spontaneous ventilation and the chest X-ray showed elevation of the left hemidiaphragm. The diagnosis of DP was confirmed by ultrasonographic assessment. Antibiotherapy and intermittent positive airway pressure ventilation by a nasal mask resulted in significant improvement in the general condition of the patient. Respiratory problems were observed only on exertion. Spontaneous recovery of DP was considered and the patient was discharged 10 days after surgery with grade 1 dyspnea. However, after six months of follow-up, increased elevation of the left hemidiaphragm was noted on the chest X-ray with worsening respiratory discomfort even at rest. Thoracoscopic diaphragmatic plication was performed. After the operation, dyspnea disappeared, the chest X-ray showed the left hemidiaphragm in its normal position, and there was marked improvement in spirometric values.