Browsing by Author "Valenzuela, Alfonso"

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    ANTI-STEATOTIC EFFECTS OF DOCOSAEXAENOIC ACID AND HYDROXYTYROSOL IN THE LIVER OF MICE FED A HIGH-FAT DIET: PPAR-A AND NRF2 UP-REGULATION, AND OF SRBP-1C AND NF-KB DOWN-REGULATION
    (2017) Valenzuela Baez, Rodrigo Wladmir; Echeverria, Francisca; Soto Alarcon, Sandra Anakaren; Orellana, Paula; Rincon-Cervera, Miguel Angel; Vargas, Romina; Valenzuela, Alfonso; Videla, Luis A.
    Background: Non-alcoholic fatty liver disease (NAFLD) is characterized by abnormal accumulation of lipids, being insulin resistance, oxidative stress, inflammation and a drastic depletion of n-3 LCPUFA the main expressions of the disease. Docosahexaenoic acid (DHA, 22:6, n-3) controls liver lipid metabolism by stimulation of lipolysis and inhibition of lipogenesis and Hydroxytyrosol (HT) exhibits strong tissue cytoprotective effects. Objetive: To evaluate the molecular mechanisms involved in the protective effects of a mixture of DHA and HT (DHA /HT), to prevent the development of NAFLD induced by high-fat diet (HFD) in mice. Methods: Male C57BL/6J mice received control diet (CD) (10% fat) or high fat diet (HFD - 60% fat), non-supplemented/ supplemented of DHA (50 mg per kg per day)/ HT (5 mg per kg per day) for 12 weeks. Parameters studied included liver histology (optical microscopy), activity of hepatic antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase (by spectrophotometry), oxidative stress indicators (glutathione, thiobarbituric acid reactants, and the antioxidant capacity of plasma), gene expression assays for PPAR-α, Nrf2, SREBP-1c and NF-κB (qPCR and ELISA), and LCPUFA profiles in liver (gas-liquid chromatography). Results: Results: HFD induced (i) liver steatosis (increasing total fat, triacylglycerols and free fatty acid content), (ii) higher fasting serum glucose, insulin levels and HOMA index, total cholesterol, triacylglycerols, TNF-α and IL-6, (iii) liver and plasma oxidative stress enhancement, (iv) depletion of n-3 LCPUFA content of liver phospholipids, increasing lipogenic and reducing lipolytic enzyme activities (v) down-regulation of PPAR-α and Nrf2, and (vi) up-regulation of SREBP-1c and NF-kB (gene expression and DNA binding activity). These changes were either reduced (p < 0.05) or normalized (compared to CD) in animals feed HFD supplemented with DHA/HT. Conclusions: DHA/HT intervention exerts anti-steatotic effects underling antioxidants and anti-inflammatory responses by improving insulin sensitivity and recovering the lipolytic/lipogenic status of the liver altered by HFD, being PPAR-α and Nrf2 up-regulation, together with SREBP-1c and NF-κB down-regulation important molecular mechanisms involved in the protective action of DHA/HT. These effects may support the potential therapeutic use of DHA/HT supplementation in the treatment of liver steatosis induced by nutritional factors and/or other etiologies. Keywords: Anti-steatotic effects; docosahexaenoic acid; hydroxytyrosol; antioxidant effects ; antiinflammatory effects
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    Critical shoulder angle and failure of conservative treatment in patients with atraumatic full thickness rotator cuff tears
    (2022) Meissner-Haecker, Arturo; Contreras Marambio, Julio César; Valenzuela, Alfonso; Delgado, Byron; Taglioni, Angelinni; Marinis Acle, Rodrigo Ignacio de; Calvo, Claudio; Soza, Francisco; Liendo Verdugo, Rodrigo Javier; Pontificia Universidad Católica de Chile. Escuela de Medicina
    Atraumatic full thickness rotator cuff tears (AFTRCT) are common lesions whose incidence increases with age. Physical therapy is an effective conservative treatment in these patients with a reported success rate near 85% within 12 weeks of treatment. The critical shoulder angle (CSA) is a radiographic metric that relates the glenoid inclination with the lateral extension of the acromion in the coronal plane. A larger CSA has been associated with higher incidence of AFTRCT and a higher re-tear rate after surgical treatment. However, no study has yet described an association between a larger CSA and failure of conservatory treatment in ARCT. The main objective of this study is to determine whether there is an association between CSA and failure of physical therapy in patients with AFTRCT. Methods: We reviewed the imaging and clinical records of 48 patients (53 shoulders), 60% female, with a mean age of 63.2 years (95% CI ± 10.4 years); treated for AFTRCT who also underwent a true anteroposterior radiograph of the shoulder within a year of diagnosis of the tear. We recorded demographic (age, sex, type of work), clinical (comorbidities), and imaging data (CSA, size and location of the tear). We divided the patients into two groups according to success or failure of conservative treatment (indication for surgery), so 21 shoulders (39.6%) required surgery and were classified as failure of conservative treatment. Univariate and multivariate analysis was performed to detect predictors of failure of conservative treatment. Results: The median CSA was 35.5º with no differences between those with failure (median 35.5º, range 29º to 48.2º) and success of conservative treatment (median 35.45º, range 30.2º to 40.3º), p = 0.978. The multivariate analysis showed a younger age in patients with failure of conservative treatment (56.14 ± 9.2 vs 67.8 ± 8.4, p < 0.001) and that male gender was also associated with failure of conservative treatment (57% of men required surgery vs 28% of women, p = 0.035). Conclusions: It is still unclear if CSA does predict failure of conservative treatment. A lower age and male gender both could predicted failure of conservative treatment in AFTRCT. Further research is needed to better address this subject.
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    Proximal humerus variable angle locking plate for the treatment of periprosthetic humeral fractures in a patient with previous tendon transfers: A case report
    (2023) Marinis Acle, Rodrigo Ignacio de; López Le-beuffe, Cristóbal Ernesto; Regan, Christina; Guarin, Sergio; Valenzuela, Alfonso; Kameid, Gonzalo; Liendo Verdugo, Rodrigo Javier
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    Straight antegrade humeral nailing and risk of iatrogenic injury of supraspinatus tendon footprint: An MRI study
    (2023) Contreras, Julio J.; Meissner, Arturo; Valenzuela, Alfonso; Liendo, Rodrigo; de Marinis, Rodrigo; Calvo, Claudio; Soza, Francisco
    Background: Straight antegrade humeral nailing (SAHN) is associated with excellent clinical results in proximal humerus fractures. The optimal entry point is the top of the humeral head. However, the anatomy is variable, and the entry point can affect supraspinatus tendon footprint (SSP-F) or fracture reduction. The aim of this study was to analyze the relationship between the SSP-F and SAHN entry point by analyzing magnetic resonance imaging (MRI) studies of the humerus.Methods: In total 58 MRI studies of entire humerus were reviewed. The mean age was 51.6 +/- 12.4 years, with 40 female patients. The distance between the SSP-F and the SAHN insertion point (critical distance: CD), the width of the footprint, and the neck-shaft angle (NSA) were measured. Univariate and multivariate analysis were performed.Results: The mean CD was 7.51 mm +/- 2.81 (0-12.9 mm) with 51.7% of proximal humerus "critical type" (CD <8 mm). The CD was found to be lower in females, with no difference found with varying age (62.5% "critical type"). CD correlated with NSA (linear regression). "Critical type" correlated with female gender and NSA (logistic regression).Discussion: More than half of the humerus are "critical types" as to SAHN and may, therefore, be at risk for procedure-related complications.