Arturo Santos

Dr. Arturo Santos


Research Focus & Metrics

Academic Career Length

33Years (1994-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 April 2012 in Ophthalmology
Verified
Journal Article
Closed access
MHMark Humayun
Mark Humayun
JDJessy D. Dorn
Jessy D. Dorn
LCLyndon da Cruz
Lyndon da Cruz
GDGislin Dagnelie
Gislin Dagnelie
JSJosé-Alain Sahel
José-Alain Sahel
RGRobert J. Greenberg
Robert J. Greenberg

1 April 1997 in Archives of Ophthalmology (1950)
Verified
Journal Article
Closed access
PDF file
ASArturo Santos
Arturo Santos
MHMark S. Humayun
Mark S. Humayun
EJEugene de Juan
Eugene de Juan
RGRobert J. Greenburg
Robert J. Greenburg
MMMarta J. Marsh
Marta J. Marsh
AMAnn H. Milam
Ann H. Milam
Objective: To determine the extent of preservation in the inner retina in retinitis pigmentosa (RP). Methods: We analyzed sectioned maculae of 21 postmortem eyes with RP and 19 age-matched, normal, postmortem eyes. Eyes were divided into 2 groups: severe and moderate RP. Cell nuclei were counted in the outer nuclear, inner nuclear, and ganglion cell layers within thirty 100-μm intervals from the foveola to 1500-μm eccentricity. Results: Statistically significant (P≤.05) loss of both the outer nuclear and ganglion cell layers was present in the groups with moderate and severe RP when compared with the control groups. However, even in the group with severe RP, 30% of the ganglion cells were histologically intact. Similarly, 78% and 88% of the inner nuclear layer cells were preserved in the groups with severe and moderate RP, respectively. Different inheritance modes showed no statistically significant differences in any of the retinal layers. Conclusions: Despite a statistically significant (P≤.05) loss of cells found in all retinal layers, a large percentage of the inner retinal neurons remained histologically intact. Current experimental therapies, such as photoreceptor transplantation and implantation of a visual prosthesis, are based on the premise that some inner retinal neurons are preserved after death of photoreceptors in RP. Our observations support this assumption.

1 October 2016 in Ophthalmology
Verified
Journal Article
Open access
LCLyndon da Cruz
Lyndon da Cruz
JDJessy D. Dorn
Jessy D. Dorn
MHMark S. Humayun
Mark S. Humayun
GDGislin Dagnelie
Gislin Dagnelie
JHJames Handa
James Handa
RGRobert J. Greenberg
Robert J. Greenberg
The Argus II Retinal Prosthesis System (Second Sight Medical Products, Inc, Sylmar, CA) was developed to restore some vision to patients blind as a result of retinitis pigmentosa (RP) or outer retinal degeneration. A clinical trial was initiated in 2006 to study the long-term safety and efficacy of the Argus II System in patients with bare or no light perception resulting from end-stage RP. Prospective, multicenter, single-arm clinical trial. Within-patient controls included the nonimplanted fellow eye and patients' native residual vision compared with their vision with the Argus II. Thirty participants in 10 centers in the United States and Europe. The worse-seeing eye of blind patients was implanted with the Argus II. Patients wore glasses mounted with a small camera and a video processor that converted images into stimulation patterns sent to the electrode array on the retina. The primary outcome measures were safety (the number, seriousness, and relatedness of adverse events) and visual function, as measured by 3 computer-based, objective tests. Secondary measures included functional vision performance on objectively scored real-world tasks. Twenty-four of 30 patients remained implanted with functioning Argus II Systems at 5 years after implantation. Only 1 additional serious adverse event was experienced after the 3-year time point. Patients performed significantly better with the Argus II on than off on all visual function tests and functional vision tasks. The 5-year results of the Argus II trial support the long-term safety profile and benefit of the Argus II System for patients blind as a result of RP. The Argus II is the first and only retinal implant to have market approval in the European Economic Area, the United States, and Canada.

1 August 2015 in Ophthalmology
Verified
Journal Article
Open access
AHAllen C Ho
Allen C Ho
MHMark S. Humayun
Mark S. Humayun
JDJessy D. Dorn
Jessy D. Dorn
LCLyndon da Cruz
Lyndon da Cruz
GDGislin Dagnelie
Gislin Dagnelie
RGRobert J. Greenberg
Robert J. Greenberg
Retinitis pigmentosa (RP) is a group of inherited retinal degenerations leading to blindness due to photoreceptor loss. Retinitis pigmentosa is a rare disease, affecting only approximately 100 000 people in the United States. There is no cure and no approved medical therapy to slow or reverse RP. The purpose of this clinical trial was to evaluate the safety, reliability, and benefit of the Argus II Retinal Prosthesis System (Second Sight Medical Products, Inc, Sylmar, CA) in restoring some visual function to subjects completely blind from RP. We report clinical trial results at 1 and 3 years after implantation. The study is a multicenter, single-arm, prospective clinical trial. There were 30 subjects in 10 centers in the United States and Europe. Subjects served as their own controls, that is, implanted eye versus fellow eye, and system on versus system off (native residual vision). The Argus II System was implanted on and in a single eye (typically the worse-seeing eye) of blind subjects. Subjects wore glasses mounted with a small camera and a video processor that converted images into stimulation patterns sent to the electrode array on the retina. The primary outcome measures were safety (the number, seriousness, and relatedness of adverse events) and visual function, as measured by 3 computer-based, objective tests. A total of 29 of 30 subjects had functioning Argus II Systems implants 3 years after implantation. Eleven subjects experienced a total of 23 serious device- or surgery-related adverse events. All were treated with standard ophthalmic care. As a group, subjects performed significantly better with the system on than off on all visual function tests and functional vision assessments. The 3-year results of the Argus II trial support the long-term safety profile and benefit of the Argus II System for patients blind from RP. Earlier results from this trial were used to gain approval of the Argus II by the Food and Drug Administration and a CE mark in Europe. The Argus II System is the first and only retinal implant to have both approvals.

Verified
Journal Article
Open access
PDF file
JGJorge Gutiérrez-Cuevas
Jorge Gutiérrez-Cuevas
ASArturo Santos
Arturo Santos
JAJuan Armendariz-Borunda
Juan Armendariz-Borunda
Obesity is now a worldwide epidemic ensuing an increase in comorbidities’ prevalence, such as insulin resistance, type 2 diabetes (T2D), metabolic dysfunction-associated fatty liver disease (MAFLD), nonalcoholic steatohepatitis (NASH), hypertension, cardiovascular disease (CVD), autoimmune diseases, and some cancers, CVD being one of the main causes of death in the world. Several studies provide evidence for an association between MAFLD and atherosclerosis and cardio-metabolic disorders, including CVDs such as coronary heart disease and stroke. Therefore, the combination of MAFLD/NASH is associated with vascular risk and CVD progression, but the underlying mechanisms linking MAFLD/NASH and CVD are still under investigation. Several underlying mechanisms may probably be involved, including hepatic/systemic insulin resistance, atherogenic dyslipidemia, hypertension, as well as pro-atherogenic, pro-coagulant, and pro-inflammatory mediators released from the steatotic/inflamed liver. MAFLD is strongly associated with insulin resistance, which is involved in its pathogenesis and progression to NASH. Insulin resistance is a major cardiovascular risk factor in subjects without diabetes. However, T2D has been considered the most common link between MAFLD/NASH and CVD. This review summarizes the evidence linking obesity with MAFLD, NASH, and CVD, considering the pathophysiological molecular mechanisms involved in these diseases. We also discuss the association of MAFLD and NASH with the development and progression of CVD, including structural and functional cardiac alterations, and pharmacological strategies to treat MAFLD/NASH and cardiovascular prevention.

12 March 2021 in Cells
Verified
Journal Article
Open access
PDF file
JGJorge Gutiérrez-Cuevas
Jorge Gutiérrez-Cuevas
ASAna Sandoval-Rodriguez
Ana Sandoval-Rodriguez
AMAlejandra Meza-Rios
Alejandra Meza-Rios
HMHugo Christian Monroy-Ramirez
Hugo Christian Monroy-Ramirez
MGMarina Galicia-Moreno
Marina Galicia-Moreno
JAJuan Armendariz-Borunda
Juan Armendariz-Borunda
Obesity is defined as excessive body fat accumulation, and worldwide obesity has nearly tripled since 1975. Excess of free fatty acids (FFAs) and triglycerides in obese individuals promote ectopic lipid accumulation in the liver, skeletal muscle tissue, and heart, among others, inducing insulin resistance, hypertension, metabolic syndrome, type 2 diabetes (T2D), atherosclerosis, and cardiovascular disease (CVD). These diseases are promoted by visceral white adipocyte tissue (WAT) dysfunction through an increase in pro-inflammatory adipokines, oxidative stress, activation of the renin-angiotensin-aldosterone system (RAAS), and adverse changes in the gut microbiome. In the heart, obesity and T2D induce changes in substrate utilization, tissue metabolism, oxidative stress, and inflammation, leading to myocardial fibrosis and ultimately cardiac dysfunction. Peroxisome proliferator-activated receptors (PPARs) are involved in the regulation of carbohydrate and lipid metabolism, also improve insulin sensitivity, triglyceride levels, inflammation, and oxidative stress. The purpose of this review is to provide an update on the molecular mechanisms involved in obesity-linked CVD pathophysiology, considering pro-inflammatory cytokines, adipokines, and hormones, as well as the role of oxidative stress, inflammation, and PPARs. In addition, cell lines and animal models, biomarkers, gut microbiota dysbiosis, epigenetic modifications, and current therapeutic treatments in CVD associated with obesity are outlined in this paper.