Pharmacologic control of oxidative stress and inflammation determines whether diabetic glomerulosclerosis progresses or decreases: A pilot study in sclerosis-prone mice

Empagliflozin ameliorates renal and metabolic derangements in obese type 2 diabetic mice by blocking advanced glycation end product-receptor axis

BACKGROUND

Although randomized clinical trials revealed that inhibitors of sodium-glucose cotransporter 2 (SGLT2) reduced the risk of cardiovascular and renal events in patients with type 2 diabetes, the underlying molecular mechanisms remain to be elucidated. Since there is accumulating evidence that AGEs and their receptor (RAGE) play a crucial role in diabetes-related complications, we examined here whether empagliflozin ameliorates renal and metabolic derangements in db/db mice, an obese type 2 diabetes animal by blocking the AGE-RAGE axis.

METHODS

Eight-week-old db/db mice were fed a 0.045% empagliflozin diet (db/db + Empa) or normal diet (db/db) for 13 weeks. The same week-old db/ + m mice were maintained on normal diet (db/ + m) used as a control. At baseline and 13 weeks after intervention, biochemical analyses in the serum and urine were performed, and kidneys and adipose tissues were obtained for morphological, immunohistochemical, and reverse transcription-polymerase chain reaction analyses.

RESULTS

Empagliflozin treatment for 13 weeks significantly reduced AGEs, Nε-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1), RAGE, NADPH oxidase-derived oxidative stress, inflammatory and fibrotic reactions in the kidneys of db/db mice of 21-week-old in association with attenuation of glomerular extracellular matrix accumulation, podocyte loss, proteinuria, and tubulointerstitial damage. Empagliflozin also reduced the AGE-RAGE-oxidative stress-induced inflammatory reactions in the adipose tissues of db/db mice, which was associated with restoration of adiponectin levels and decreased insulin resistance. Serum MG-H1 levels of control and db/db mice at 21 weeks of age were significantly associated with proteinuria, tubulointerstitial damage, tissue AGEs levels, and serum monocyte chemoattractant protein-1 and adiponectin (inversely) values.

CONCLUSIONS

Our present findings suggest that empagliflozin could ameliorate renal and metabolic derangements in type 2 diabetes animals by attenuating the AGE-RAGE axis.

Modulation of circulating levels of advanced glycation end products and its impact on intima-media thickness of both common carotid arteries: CORDIOPREV randomised controlled trial

BACKGROUND

Increasing evidence supports the role of advanced glycation end products (AGEs) in atherosclerosis in both diabetic and non-diabetic patients, suggesting that therapeutic strategies targeting AGEs may offer potential benefits in this population. The Mediterranean diet is associated with improved biomarkers and anthropometric measurements related with atherosclerosis in addition to its ability to modulate AGE metabolism. Our aim was to determine whether the reduction in atherosclerosis progression (measured by changes in intima-media thickness of both common carotid arteries (IMT-CC)), observed after consumption of a Mediterranean diet compared to a low-fat diet, is associated with a modulation of circulating AGE levels in patients with coronary heart disease (CHD).

METHODS

1002 CHD patients were divided in: (1) Non-increased IMT-CC patients, whose IMT-CC was reduced or not changed after dietary intervention and (2) Increased IMT-CC patients, whose IMT-CC was increased after dietary intervention. Serum AGE levels (methylglyoxal-MG and Nε-Carboxymethyllysine-CML) and parameters related to AGE metabolism (AGER1 and GloxI mRNA and sRAGE levels) and reduced glutathione (GSH) levels were measured before and after 5-years of dietary intervention.

RESULTS

The Mediterranean diet did not affect MG levels, whereas the low-fat diet significantly increased them compared to baseline (p = 0.029), leading to lower MG levels following the Mediterranean diet than the low-fat diet (p < 0.001). The Mediterranean diet, but not the low-fat diet, produced an upregulation of AGE metabolism, with increased AGER1 and GloxI gene expression as well as increased GSH and sRAGE levels in Non-increased IMT-CC patients (all p < 0.05). Although the Mediterranean diet increased MG levels in Increased IMT-CC patients, this increment was lower compared to the low-fat diet (all p < 0.05).

CONCLUSIONS

Our results suggest that an improvement in modulation of AGE metabolism, which facilitates better management of circulating AGE levels, may be one of the mechanisms through which the Mediterranean diet, compared to a low-fat diet, reduces the progression of atherosclerosis in patients with CHD. Trial registration https://clinicaltrials.gov/ct2/show/NCT00924937 , Clinicaltrials.gov number, NCT00924937.

Oxidative stress and senescence in aging kidneys: the protective role of SIRT1

Aging leads to a gradual decline in kidney function, making the kidneys increasingly vulnerable to various diseases. Oxidative stress, together with cellular senescence, has been established as paramount in promoting the aging process of the kidney. Oxidative stress, defined as an imbalance between ROS formation and antioxidant defense mechanisms, has been implicated in the kidney's cellular injury, inflammation, and premature senescence. Concurrently, the accumulation of SCs in the kidney also exacerbates oxidative stress via the secretion of pro-inflammatory and tissue-damaging factors as the senescence-associated secretory phenotype (SASP). Recently, SIRT1, a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, has been pivotal in combating oxidative stress and cellular senescence in the aging kidney. SIRT1 acts as a potential antioxidant molecule through myriad pathways that influence diverse transcription factors and enzymes essential in maintaining redox homeostasis. SIRT1 promotes longevity and renal health by modulating the acetylation of cell cycle and senescence pathways. This review covers the complex relationship between oxidative stress and cellular senescence in the aging kidney, emphasizing the protective role of SIRT1. See also the graphical abstract(Fig. 1).

Efficacy of pentosan polysulfate in in vitro models of lysosomal storage disorders: Fabry and Gaucher Disease

Gaucher and Fabry diseases are the most prevalent sphingolipidoses. Chronic inflammation is activated in those disorders, which could play a role in pathogenesis. Significant degrees of amelioration occur in patients upon introduction of specific therapies; however, restoration to complete health status is not always achieved. The idea of an adjunctive therapy that targets inflammation may be a suitable option for patients. PPS is a mixture of semisynthetic sulfated polyanions that have been shown to have anti-inflammatory effects in mucopolysaccharidosis type I and II patients and animal models of type I, IIIA and VI. We hypothesized PPS could be a useful adjunctive therapy to inflammation for Gaucher and Fabry diseases. The objective of this work is to analyze the in vitro effect of PPS on inflammatory cytokines in cellular models of Gaucher and Fabry diseases, and to study its effect in Gaucher disease associated in vitro bone alterations. Cultures of peripheral blood mononuclear cells from Fabry and Gaucher patients were exposed to PPS. The secretion of proinflammatory cytokines was significantly reduced. Peripheral blood cells exposed to PPS from Gaucher patients revealed a reduced tendency to differentiate to osteoclasts. Osteoblasts and osteocytes cell lines were incubated with an inhibitor of glucocerebrosidase, and conditioned media was harvested in order to analyze if those cells secrete factors that induce osteoclastogenesis. Conditioned media from this cell cultures exposed to PPS produced lower numbers of osteoclasts. We could demonstrate PPS is an effective molecule to reduce the production of proinflammatory cytokines in in vitro models of Fabry and Gaucher diseases. Moreover, it was effective at ameliorating bone alterations of in vitro models of Gaucher disease. These results serve as preclinical supportive data to start clinical trials in human patients to analyze the effect of PPS as a potential adjunctive therapy for Fabry and Gaucher diseases.