Effects of fenofibrate on renal function in patients with type 2 diabetes mellitus: the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) Study

Fenofibrate and risk of end-stage renal disease: A nationwide cohort study

AIM

Previous studies have shown that fenofibrate improves outcomes such as albuminuria and estimated glomerular filtration rate decline. We hypothesize that fenofibrate has renoprotective effects and prevents or delays the development of end-stage renal disease. The objective of this study is to investigate the risk of incident end-stage renal disease in relation to fenofibrate treatment in patients who are already taking statins.

MATERIALS AND METHODS

We performed a nationwide population-based cohort study using data from the Korea National Health Information Database from 2010 to 2017. Among adults using statins, 413 715 fenofibrate users were compared with 413 715 fenofibrate non-users after 1:1 age, sex and triglyceride matching. The endpoint of this study was incident end-stage renal disease.

RESULTS

During a median 3.96-year follow-up, the incidence per 1000 person years of end-stage renal disease was lower in fenofibrate users than in fenofibrate non-users (0.885 vs. 0.960, p < 0.0001). The hazard ratio for end-stage renal disease was lower (0.763, 95% confidence interval 0.710-0.821) in fenofibrate users. This association was significant in patients with hypertension, proteinuria and an estimated glomerular filtration rate <60 mL/min/1.732.

CONCLUSIONS

Fenofibrate use in patients taking statins with either hypertension, proteinuria, or decreased estimated glomerular filtration rate is associated with a low risk of incident end-stage renal disease. To confirm the renoprotective effect of fenofibrate in chronic kidney disease, a randomized controlled trial is warranted.

Metabolism at the crossroads of inflammation and fibrosis in chronic kidney disease

Chronic kidney disease (CKD), defined as persistent (>3 months) kidney functional loss, has a growing prevalence (>10% worldwide population) and limited treatment options. Fibrosis driven by the aberrant accumulation of extracellular matrix is the final common pathway of nearly all types of chronic repetitive injury in the kidney and is considered a hallmark of CKD. Myofibroblasts are key extracellular matrix-producing cells that are activated by crosstalk between damaged tubules and immune cells. Emerging evidence indicates that metabolic alterations are crucial contributors to the pathogenesis of kidney fibrosis by affecting cellular bioenergetics and metabolite signalling. Immune cell functions are intricately connected to their metabolic characteristics, and kidney cells seem to undergo cell-type-specific metabolic shifts in response to damage, all of which can determine injury and repair responses in CKD. A detailed understanding of the heterogeneity in metabolic reprogramming of different kidney cellular subsets is essential to elucidating communication processes between cell types and to enabling the development of metabolism-based innovative therapeutic strategies against CKD.

Design, recruitment and baseline characteristics of the LENS trial

BACKGROUND

Findings from cardiovascular outcome trials suggest that treatment with fenofibrate may reduce the progression of diabetic retinopathy. However, no dedicated large-scale randomised trials have yet investigated this hypothesis.

METHODS

LENS is a streamlined randomised double-masked placebo-controlled trial, based in Scotland, assessing whether treatment with fenofibrate (145 mg tablet daily or, in the context of impaired renal function, on alternate days) in people with early retinopathy reduces progression to referable diabetic retinopathy (defined in NHS Scotland's Diabetic Eye Screening grading scheme as referable background or proliferative retinopathy, or referable maculopathy in either eye) or treatment with retinal laser, intravitreal injections or vitrectomy. Adults with diabetes mellitus and non-referable retinopathy (mild background retinopathy in both eyes or observable background retinopathy in one/both eyes at the most recent NHS retinal screening assessment; or observable maculopathy in one/both eyes in the previous 3 years) were eligible. Potential participants were identified from routinely collected healthcare data and followed up using regular contact from the research team and linkage to national electronic morbidity, mortality, biochemistry and retinal screening records. Study treatment was mailed to participants.

RESULTS

Between 18 September 2018 and 27 July 2021, 1151 participants were randomised. Their mean age was 61 (SD 12) years, 312 (27%) were female and 305 (26%) had type 1 diabetes. 96% had bilateral mild background retinopathy and 10% had observable maculopathy.

CONCLUSIONS

LENS will provide a robust evaluation of the efficacy of treating people at risk of progression of diabetic retinopathy with fenofibrate. Results are anticipated in mid-2024.

TRIAL REGISTRATIONS

NCT03439345; ISRCTN15073006; EuDRACT 2016-002656-24.

Haptoglobin phenotype and levels in type 2 diabetes and effects of fenofibrate

AIMS/HYPOTHESIS

In diabetes haptoglobin (Hp) 2 vs Hp 1 allelic product is associated with cardiac and renal complications. Few studies report both Hp phenotype and Hp levels. In a Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial substudy we evaluated the Hp phenotype, Hp levels, and fenofibrate effects.

MATERIALS AND METHODS

In 480 adults with type 2 diabetes (T2D) the Hp phenotype was assessed and the Hp level quantified (both using ELISAs assays) in plasma from baseline, after 6 weeks of fenofibrate, and (in n = 200) at 2 years post-randomization to fenofibrate or placebo.

RESULTS

The Hp phenotypes 1-1, 2-1, and 2-2 frequencies were 15%, 49%, and 36%, respectively. Baseline Hp levels differed by phenotype (P < 0.0001) and decreased (median 21%) after 6 weeks fenofibrate in all phenotypes (adjusted mean (95% CI): -0.27 (-0.32, -0.23) mg/mL in Hp 1-1, -0.29 (-0.31, -0.27) mg/mL in Hp 2-1 and -0.05 (-0.07, -0.02) mg/mL in Hp 2-2 (P = 0.005 and P = 0.055 vs Hp 1-1 and Hp 2-1, respectively)). At 2 years post-randomization the Hp levels in the placebo group had returned to baseline, whilst the fenofibrate-group levels remained similar to the 6 week levels.

CONCLUSIONS

In type 2 diabetes, Hp levels differ by Hp phenotype and are decreased by fenofibrate in all phenotypes, but the effect is diminished in Hp 2-2.

Effect of Fenofibrate on Progression of Diabetic Retinopathy

BACKGROUND

Findings from cardiovascular outcome trials suggest that fenofibrate therapy may reduce the progression of diabetic retinopathy.

METHODS

We recruited and followed adults with nonreferable diabetic retinopathy or maculopathy using the national Diabetic Eye Screening (DES) program in Scotland. We randomly assigned participants to receive 145-mg fenofibrate tablets or placebo (taken daily or, in those with impaired renal function, on alternate days). The primary outcome was a composite of developing referable diabetic retinopathy or maculopathy (based on Scotland's DES grading scheme) or treatment (intravitreal injection, retinal laser, vitrectomy) for retinopathy or maculopathy.

RESULTS

A total of 1151 participants were randomly assigned to treatment. During a median of 4.0 years, progression to referable diabetic retinopathy or maculopathy, or treatment thereof, occurred in 131 (22.7%) of 576 participants in the fenofibrate group and 168 (29.2%) of 575 in the placebo group (hazard ratio, 0.73; 95% confidence interval [CI], 0.58 to 0.91; P=0.006). In the fenofibrate group compared with the placebo group, the frequencies for any progression of retinopathy or maculopathy were 185 (32.1%) vs. 231 (40.2%); hazard ratio, 0.74; 95% CI, 0.61 to 0.90 and for the development of macular edema were 22 (3.8%) vs. 43 (7.5%); hazard ratio, 0.50; 95% CI, 0.30 to 0.84. Seventeen (3.0%) participants assigned fenofibrate and 28 (4.9%) assigned placebo were given treatment for retinopathy (hazard ratio, 0.58; 95% CI, 0.31 to 1.06). There was no effect on visual function, quality of life, or visual acuity. Trial-averaged estimated glomerular filtration rate was 7.9 (95% CI, 6.8 to 9.1) ml/min/1.73 m2 lower in participants in the fenofibrate group compared with the placebo group. Serious adverse events occurred in 208 (36.1%) participants allocated fenofibrate and 204 (35.5%) participants allocated placebo.

CONCLUSIONS

Fenofibrate reduced progression of diabetic retinopathy compared with placebo among participants with early retinal changes. (Funded by the National Institute for Health and Care Research; ClinicalTrials.gov number, NCT03439345; ISRCTN number, ISRCTN15073006.).

Lessons from PROMINENT and prospects for pemafibrate

The neutral result of the PROMINENT trial has led to questions about the future for pemafibrate. This commentary discusses possible reasons for the lack of benefit observed in the trial. There were, however, indicators suggesting therapeutic potential in microvascular ischaemic complications associated with peripheral artery disease, with subsequent analysis showing reduction in the incidence of lower extremity ischaemic ulceration or gangrene. Reassurance about the safety of pemafibrate, together with emerging data from PROMINENT and experimental studies, also suggest benefit with pemafibrate in non-alcoholic fatty liver disease (alternatively referred to as metabolic dysfunction-associated steatotic liver disease) and microangiopathy associated with diabetes, which merit further study.

The key role of altered tubule cell lipid metabolism in kidney disease development

Kidney epithelial cells have very high energy requirements, which are largely met by fatty acid oxidation. Complex changes in lipid metabolism are observed in patients with kidney disease. Defects in fatty acid oxidation and increased lipid uptake, especially in the context of hyperlipidemia and proteinuria, contribute to this excess lipid build-up and exacerbate kidney disease development. Recent studies have also highlighted the role of increased de novo lipogenesis in kidney fibrosis. The defect in fatty acid oxidation causes energy starvation. Increased lipid uptake, synthesis, and lower fatty acid oxidation can cause toxic lipid build-up, reactive oxygen species generation, and mitochondrial damage. A better understanding of these metabolic processes may open new treatment avenues for kidney diseases by targeting lipid metabolism.

Molecular mechanism of renal lipid accumulation in diabetic kidney disease

Diabetic kidney disease (DKD) is a leading cause of end stage renal disease with unmet clinical demands for treatment. Lipids are essential for cell survival; however, renal cells have limited capability to metabolize overloaded lipids. Dyslipidaemia is common in DKD patients and renal ectopic lipid accumulation is associated with disease progression. Unveiling the molecular mechanism involved in renal lipid regulation is crucial for exploring potential therapeutic targets. In this review, we focused on the mechanism underlying cholesterol, oxysterol and fatty acid metabolism disorder in the context of DKD. Specific regulators of lipid accumulation in different kidney compartment and TREM2 macrophages, a lipid-related macrophages in DKD, were discussed. The role of sodium-glucose transporter 2 inhibitors in improving renal lipid accumulation was summarized.

Elevated apolipoprotein C3 augments diabetic kidney disease and associated atherosclerosis in type 2 diabetes

Diabetes increases the risk of both cardiovascular disease and kidney disease. Notably, most of the excess cardiovascular risk in people with diabetes is in those with kidney disease. Apolipoprotein C3 (APOC3) is a key regulator of plasma triglycerides, and it has recently been suggested to play a role in both type 1 diabetes-accelerated atherosclerosis and kidney disease progression. To investigate if APOC3 plays a role in kidney disease in people with type 2 diabetes, we analyzed plasma levels of APOC3 from the Veterans Affairs Diabetes Trial. Elevated baseline APOC3 levels predicted a greater loss of renal function. To mechanistically test if APOC3 plays a role in diabetic kidney disease and associated atherosclerosis, we treated black and tan, brachyury, WT and leptin-deficient (OB; diabetic) mice, a model of type 2 diabetes, with an antisense oligonucleotide (ASO) to APOC3 or a control ASO, all in the setting of human-like dyslipidemia. Silencing APOC3 prevented diabetes-augmented albuminuria, renal glomerular hypertrophy, monocyte recruitment, and macrophage accumulation, partly driven by reduced ICAM1 expression. Furthermore, reduced levels of APOC3 suppressed atherosclerosis associated with diabetes. This suggests that targeting APOC3 might benefit both diabetes-accelerated atherosclerosis and kidney disease.

Switching from Conventional Fibrates to Pemafibrate Has Beneficial Effects on the Renal Function of Diabetic Subjects with Chronic Kidney Disease

BACKGRUOUND

Fibrates have renal toxicity limiting their use in subjects with chronic kidney disease (CKD). However, pemafibrate has fewer toxic effects on renal function. In the present analysis, we evaluated the effects of pemafibrate on the renal function of diabetic subjects with or without CKD in a real-world clinical setting.

METHODS

We performed a sub-analysis of data collected during a multi-center, prospective, observational study of the effects of pemafibrate on lipid metabolism in subjects with type 2 diabetes mellitus complicated by hypertriglyceridemia (the PARM-T2D study). The participants were allocated to add pemafibrate to their existing regimen (ADD-ON), switch from their existing fibrate to pemafibrate (SWITCH), or continue conventional therapy (CTRL). The changes in estimated glomerular filtration rate (eGFR) over 52 weeks were compared among these groups as well as among subgroups created according to CKD status.

RESULTS

Data for 520 participants (ADD-ON, n=166; SWITCH, n=96; CTRL, n=258) were analyzed. Of them, 56.7% had CKD. The eGFR increased only in the SWITCH group, and this trend was also present in the CKD subgroup (P<0.001). On the other hand, eGFR was not affected by switching in participants with severe renal dysfunction (G3b or G4) and/or macroalbuminuria. Multivariate analysis showed that being older and a switch from fenofibrate were associated with elevation in eGFR (both P<0.05).

CONCLUSION

A switch to pemafibrate may be associated with an elevation in eGFR, but to a lesser extent in patients with poor renal function.

Not enough known about fenofibrate's kidney effects in people with Type 2 diabetes

Globally ≈10% of adults have diabetes, with 80% in disadvantaged regions, hence low-cost renoprotective agents are desirable. Fenofibrate demonstrated microvascular benefits in several cardiovascular end-point diabetes trials, but knowledge of effects in late-stage kidney disease is limited. We report new FIELD substudy data and call for further kidney outcomes data.

Astragaloside IV attenuates renal tubule injury in DKD rats via suppression of CD36-mediated NLRP3 inflammasome activation

Background

In recent years, diabetic kidney disease (DKD) has emerged as a prominent factor contributing to end-stage renal disease. Tubulointerstitial inflammation and lipid accumulation have been identified as key factors in the development of DKD. Earlier research indicated that Astragaloside IV (AS-IV) reduces inflammation and oxidative stress, controls lipid accumulation, and provides protection to the kidneys. Nevertheless, the mechanisms responsible for its protective effects against DKD have not yet been completely elucidated.

Purpose

The primary objective of this research was to examine the protective properties of AS-IV against DKD and investigate the underlying mechanism, which involves CD36, reactive oxygen species (ROS), NLR family pyrin domain containing 3 (NLRP3), and interleukin-1β (IL-1β).

Methods

The DKD rat model was created by administering streptozotocin along with a high-fat diet. Subsequently, the DKD rats and palmitic acid (PA)-induced HK-2 cells were treated with AS-IV. Atorvastatin was used as the positive control. To assess the therapeutic effects of AS-IV on DKD, various tests including blood sugar levels, the lipid profile, renal function, and histopathological examinations were conducted. The levels of CD36, ROS, NLRP3, Caspase-1, and IL-1β were detected using western blot analysis, PCR, and flow cytometry. Furthermore, adenovirus-mediated CD36 overexpression was applied to explore the underlying mechanisms through in vitro experiments.

Results

In vivo experiments demonstrated that AS-IV significantly reduced hyperglycemia, dyslipidemia, urinary albumin excretion, and serum creatinine levels in DKD rats. Additionally, it improved renal structural abnormalities and suppressed the expression of CD36, NLRP3, IL-1β, TNF-α, and MCP-1. In vitro experiments showed that AS-IV decreased CD36 expression, lipid accumulation, and lipid ROS production while inhibiting NLRP3 activation and IL-1β secretion in PA-induced HK-2 cells.

Conclusion

AS-IV alleviated renal tubule interstitial inflammation and tubule epithelial cell apoptosis in DKD rats by inhibiting CD36-mediated lipid accumulation and NLRP3 inflammasome activation.

High-Dose Fenofibrate Stimulates Multiple Cellular Stress Pathways in the Kidney of Old Rats

We investigated the age-related effects of the lipid-lowering drug fenofibrate on renal stress-associated effectors. Young and old rats were fed standard chow with 0.1% or 0.5% fenofibrate. The kidney cortex tissue structure showed typical aging-related changes. In old rats, 0.1% fenofibrate reduced the thickening of basement membranes, but 0.5% fenofibrate exacerbated interstitial fibrosis. The PCR array for stress and toxicity-related targets showed that 0.1% fenofibrate mildly downregulated, whereas 0.5% upregulated multiple genes. In young rats, 0.1% fenofibrate increased some antioxidant genes' expression and decreased the immunoreactivity of oxidative stress marker 4-HNE. However, the activation of cellular antioxidant defenses was impaired in old rats. Fenofibrate modulated the expression of factors involved in hypoxia and osmotic stress signaling similarly in both age groups. Inflammatory response genes were variably modulated in the young rats, whereas old animals presented elevated expression of proinflammatory genes and TNFα immunoreactivity after 0.5% fenofibrate. In old rats, 0.1% fenofibrate more prominently than in young animals induced phospho-AMPK and PGC1α levels, and upregulated fatty acid oxidation genes. Our results show divergent effects of fenofibrate in young and old rat kidneys. The activation of multiple stress-associated effectors by high-dose fenofibrate in the aged kidney warrants caution when applying fenofibrate therapy to the elderly.

Treating NASH by targeting peroxisome proliferator-activated receptors

The pathophysiology of non-alcoholic steatohepatitis (NASH) encompasses a complex set of intra- and extrahepatic driving mechanisms, involving numerous metabolic, inflammatory, vascular and fibrogenic pathways. The peroxisome proliferator-activated receptors (PPARs) α, β/δ and γ belong to the nuclear receptor family of ligand-activated transcription factors. Activated PPARs modulate target tissue transcriptomic profiles, enabling the body's adaptation to changing nutritional, metabolic and inflammatory environments. PPARs hence regulate several pathways involved in NASH pathogenesis. Whereas single PPAR agonists exert robust anti-NASH activity in several preclinical models, their clinical effects on histological endpoints of NASH resolution and fibrosis regression appear more modest. Simultaneous activation of several PPAR isotypes across different organs and within-organ cell types, resulting in pleiotropic actions, enhances the therapeutic potential of PPAR agonists as pharmacological agents for NASH and NASH-related hepatic and extrahepatic morbidity, with some compounds having already shown clinical efficacy on histological endpoints.

Increased intracellular miR-142 in adults with Type 1 diabetes

microRNAs (miRs), including miR-142, modulate gene expression and processes implicated in vascular damage and may serve as therapeutic targets and agents, including in Type 1 diabetes (T1D). The project aimed to assess whether miR-142 levels differ between people with and without T1D, and to analyse miR-142 associations with cardiovascular (CVD) risk factors. Intracellular miRs were isolated from whole blood cell pellets using TRIzol-based methodology. In a cross-sectional study in 102 adults cellular miR-142 levels were significantly higher (on unadjusted and adjusted analyses) in 69 adults with T1D relative to 33 non-diabetic subjects: mean ± SD, 3.53 ± 3.66 vs. 1.25 ± 0.78, p < 0.0002, but were not related to HbA1c levels. Further miR-142 research, including longitudinal and intervention studies and basic science are of interest. miR-142 may be valuable in clinical practice for predicting health and as a treatment target.

Regulation of pericyte metabolic reprogramming restricts the AKI to CKD transition

BACKGROUND AND AIMS

Acute kidney injury (AKI) is associated with high morbidity and mortality and is recognized as a long-term risk factor for progression to chronic kidney disease (CKD). The AKI to CKD transition is characterized by interstitial fibrosis and the proliferation of collagen-secreting myofibroblasts. Pericytes are the major source of myofibroblasts in kidney fibrosis. However, the underlying mechanism of pericyte-myofibroblast transition (PMT) is still unclear. Here we investigated the role of metabolic reprogramming in PMT.

METHODS

Unilateral ischemia/reperfusion-induced AKI to CKD mouse model and TGF-β-treated pericyte-like cells were used to detect the levels of fatty acid oxidation (FAO) and glycolysis, and the critical signaling pathways during PMT under the treatment of drugs regulating metabolic reprogramming.

RESULTS

PMT is characterized by a decrease in FAO and an increase in glycolysis. Enhancement of FAO by the peroxisome proliferator-activated receptor gamma coactivator-1α (PGC1α) activator ZLN-005 or suppression of glycolysis by the hexokinase 2 (HK2) inhibitor 2-DG can inhibit PMT, preventing the transition of AKI to CKD. Mechanistically, AMPK modulates various pathways involved in the metabolic switch from glycolysis to FAO. Specifically, the PGC1α-CPT1A pathway activates FAO, while inhibition of the HIF1α-HK2 pathway drives glycolysis inhibition. The modulations of these pathways by AMPK contribute to inhibiting PMT.

CONCLUSIONS

Metabolic reprogramming controls the fate of pericyte transdifferentiation and targets the abnormal metabolism of pericytes can effectively prevent AKI to CKD transition.

Hypertriglyceridemia is associated with decline of estimated glomerular filtration rate and risk of end-stage kidney disease in a real-word Italian cohort: Evidence from the TG-RENAL Study

BACKGROUND

This analysis investigated the role of hypertriglyceridemia on renal function decline and development of end-stage kidney disease (ESKD) in a real-world clinical setting.

METHODS

A retrospective analysis using administrative databases of 3 Italian Local Health Units was performed searching patients with at least one plasma triglyceride (TG) measurement between 2013 and June 2020, followed-up until June 2021. Outcome measures included reduction in estimated glomerular filtration rate (eGFR) ≥30% from baseline and ESKD onset. Subjects with normal (normal-TG), high (HTG) and very high TG levels (vHTG) (respectively <150 mg/dL, 150-500 mg/dL and >500 mg/dL) were comparatively evaluated.

RESULTS

Overall 45,000 subjects (39,935 normal-TGs, 5,029 HTG and 36 vHTG) with baseline eGFR of 96.0 ± 66.4 mL/min were considered. The incidence of eGFR reduction was 27.1 and 31.1 and 35.1 per 1000 person-years, in normal-TG, HTG and vHTG subjects, respectively (P<0.01). The incidence of ESKD was 0.7 and 0.9 per 1000 person-years, in normal-TG and HTG/vHTG subjects, respectively (P<0.01). Univariate and multivariate analyses revealed that HTG subjects had a risk of eGFR reduction or ESKD occurrence (composite endpoint) increased by 48% compared to normal-TG subjects (adjusted OR:1.485, 95%CI 1.300-1.696; P<0.001). Moreover, each 50 mg/dL increase in TG levels resulted in significantly greater risk of eGFR reduction (OR:1.062, 95%CI 1.039-1.086 P<0.001) and ESKD (OR:1.174, 95%CI 1.070-1.289, P = 0.001).

CONCLUSIONS

This real-word analysis in a large cohort of individuals with low-to-moderate cardiovascular risk suggests that moderate-to-severe elevation of plasma TG levels is associated with a significantly increased risk of long-term kidney function deterioration.

Transcriptional regulation of proximal tubular metabolism in acute kidney injury

The kidney, and in particular the proximal tubule (PT), has a high demand for ATP, due to its function in bulk reabsorption of solutes. In normal PT, ATP levels are predominantly maintained by fatty acid β-oxidation (FAO), the tricarboxylic acid (TCA) cycle, and oxidative phosphorylation. The normal PT also undertakes gluconeogenesis and metabolism of amino acids. Acute kidney injury (AKI) results in profound PT metabolic alterations, including suppression of FAO, gluconeogenesis, and metabolism of some amino acids, and upregulation of glycolytic enzymes. Recent studies have elucidated new transcriptional mechanisms regulating metabolic pathways in normal PT, as well as the metabolic switch in AKI. A number of transcription factors have been shown to play important roles in FAO, which are themselves downregulated in AKI, while hypoxia-inducible factor 1α, which is upregulated in ischemia-reperfusion injury, is a likely driver of the upregulation of glycolytic enzymes. Transcriptional regulation of amino acid metabolic pathways is less well understood, except for catabolism of branched-chain amino acids, which is likely suppressed in AKI by upregulation of Krüppel-like factor 6. This review will focus on the transcriptional regulation of specific metabolic pathways in normal PT and in AKI, as well as highlighting some of the gaps in knowledge and challenges that remain to be addressed.

Drug repurposing in autosomal dominant polycystic kidney disease

Autosomal dominant polycystic kidney disease is characterized by progressive kidney cyst formation that leads to kidney failure. Tolvaptan, a vasopressin 2 receptor antagonist, is the only drug approved to treat patients with autosomal dominant polycystic kidney disease who have rapid disease progression. The use of tolvaptan is limited by reduced tolerability from aquaretic effects and potential hepatotoxicity. Thus, the search for more effective drugs to slow down the progression of autosomal dominant polycystic kidney disease is urgent and challenging. Drug repurposing is a strategy for identifying new clinical indications for approved or investigational medications. Drug repurposing is increasingly becoming an attractive proposition because of its cost-efficiency and time-efficiency and known pharmacokinetic and safety profiles. In this review, we focus on the repurposing approaches to identify suitable drug candidates to treat autosomal dominant polycystic kidney disease and prioritization and implementation of candidates with high probability of success. Identification of drug candidates through understanding of disease pathogenesis and signaling pathways is highlighted.

Amelioration of diabetic kidney injury with dapagliflozin is associated with suppressing renal HMGB1 expression and restoring autophagy in obese mice

Diabetic kidney disease (DKD) is a major cause of chronic and end-stage renal disease in diabetic patients. Here, we investigated protective effects and possible mechanisms of dapagliflozin on renal injury in diabetic mice. DKD mice were established by high fat diet (HFD) feeding. Half of DKD mice were randomly assigned to receive dapagliflozin treatment (200 μg/day) for 8 weeks. Renal lipid droplets, fibrosis, oxidative and endoplasmic reticulum stress were evaluated. Glomerular injury was assessed by immunohistochemistry and transmission electron microscopy. Dapagliflozin led to marked inhibition of ROS levels and endoplasmic reticulum stress in diabetic mice. HFD-induced loss of Podocin and Nephrin, and impaired podocytes were also improved with the treatment. Importantly, overexpression of HMGB1 and suppressed autophagy in the kidney were partly reversed by dapagliflozin. Therefore, we speculate that protective effects of dapagliflozin on DKD may be associated with suppression of HMGB1 expression and restoration of autophagy in the kidney.

The effects of pemafibrate and omega-3 fatty acid ethyl on apoB-48 in dyslipidemic patients treated with statin: A prospective, multicenter, open-label, randomized, parallel group trial in Japan (PROUD48 study)

Background

We compared the lowering effects of pemafibrate and omega-3 fatty acid ethyl on fasting apolipoprotein (apo) B-48 (apoB-48), a marker that reflects postprandial hypertriglyceridemia, which is one of the residual risks for atherosclerotic cardiovascular disease (ASCVD) with statin treatment.

Methods

This prospective, multicenter, open-label, randomized, parallel group trial was conducted at 4 medical institutions between April 2020 and May 2022. A total of 126 ambulatory patients with dyslipidemia receiving statin treatment for more than 4 weeks, aged 20-79 years with fasting triglyceride (TG) levels of ≥177 mg/dl were randomly assigned to 16-week pemafibrate 0.4 mg per day treatment group (PEMA, n = 63) or omega-3 fatty acid ethyl 4 g per day treatment group (OMEGA-3, n = 63). The primary endpoint was the percentage change in fasting apoB-48 from baseline to week 16.

Results

The percentage changes in fasting apoB-48 in PEMA and OMEGA-3 were -50.8% (interquartile range -62.9 to -30.3%) and -17.5% (-38.3 to 15.3%) (P < 0.001), respectively. As the secondary endpoints, the changes in fasting apoB-48 in PEMA and OMEGA-3 were -3.10 μg/ml (-5.63 to -1.87) and -0.90 μg/ml (-2.95 to 0.65) (P < 0.001), respectively. Greater decreases with significant differences in the percentage changes in TG, remnant lipoprotein cholesterol, apoC-III, fasting plasma glucose, alanine aminotransferase, gamma-glutamyl transpeptidase, and alkaline phosphatase were observed in PEMA, compared with OMEGA-3. Greater increases with significant differences in those in high-density lipoprotein (HDL) cholesterol, apoA-I, and apoA-II were observed in PEMA, compared with OMEGA-3. PEMA showed anti-atherosclerotic lipoprotein profiles in gel-permeation high-performance liquid chromatography analyses, compared with OMEGA-3. Although adverse events occurred in 9 of 63 (14.3%) patients in PEMA and 3 of 63 (4.8%) patients in OMEGA-3, no serious adverse events associated with drug were observed in either group.

Conclusions

This is the first randomized trial to compare the lowering effects of pemafibrate and omega-3 fatty acid ethyl on fasting apoB-48. We concluded that pemafibrate was superior to omega-3 fatty acid ethyl in lowering effect of fasting apoB-48. Pemafibrate is expected to reduce the residual risk for ASCVD with statin treatment.

Clinical trial registration

https://rctportal.niph.go.jp/en, identifier jRCTs071200011.

Strong Negative Association of non-HDL Cholesterol Goal Achievement With Incident CKD Among Adults With Diabetes

Context

The relative importance of the control of different metabolic risk factors for the prevention of chronic kidney disease among patients with diabetes in real life conditions is insufficiently understood.

Objective

We evaluated the effect of the achievement of glycated hemoglobin A_1c (HbA_1c), systolic blood pressure (SBP), and low-density lipoprotein cholesterol (LDLc) or non-high-density lipoprotein cholesterol (non-HDLc) goals (ABC goals) on the development of incident chronic kidney disease (iCKD) among patients with diabetes.

Methods

In a nationwide registry of all individuals diagnosed with diabetes assisted by the health system in Colombia, we analyzed the association between baseline or sustained goal achievement and development of iCKD over a 4-year follow-up. iCKD was defined as a new occurrence of an estimated glomerular filtration rate less than 60 mL/min/1.73 m², hemodialysis, peritoneal dialysis, or kidney transplant.

Results

The study included 998 790 adults with diabetes (56% female, mean age 59). There were 125 626 cases of iCKD. After adjustment for multiple confounders, a baseline SBP less than 130 mm Hg (odds ratio [OR] 0.79 [0.78-0.80]) and a baseline HbA_1c less than 7.0% (OR 0.86 [0.85-0.87]) were negatively associated with iCKD. Sustained achievement showed stronger negative associations with iCKD than just baseline achievement. Considering each goal separately, sustained non-HDLc less than 130 mg/dL had the strongest negative association with iCKD (OR 0.67 [0.65-0.69]). Patients who maintained the triple ABC goal over the entire follow-up had 32% (29-34) lower odds of developing CKD, 38% (34-42) if they additionally kept a normal body mass index (BMI). Sustained ABC control including a normal BMI was more strongly associated with a lower incidence of CKD in patients of Black race (OR 0.72 vs 0.89; P for interaction = .002).

Conclusion

At the country level, sustained achievement of ABC goals and most especially non-HDLc were associated with substantial reductions in iCKD.

Effects of pemafibrate on lipid metabolism in patients with type 2 diabetes and hypertriglyceridemia: A multi-center prospective observational study, the PARM-T2D study

AIMS

Pemafibrate, a novel selective peroxisome proliferator-activated receptor modulator, was shown to ameliorate lipid abnormalities in a phase III clinical trial of patients with type 2 diabetes mellitus (T2DM). However, its efficacy has not been demonstrated in real-world clinical practice in patients with T2DM.

METHODS

We performed a multi-center prospective observational study of the use of pemafibrate in patients with T2DM and hypertriglyceridemia versus conventional therapy, with or without a fibrate. The primary outcomes were the changes from baseline in fasting serum triglyceride (TG) and high-density lipoprotein-cholesterol (HDL-C) concentrations at week 52.

RESULTS

We recruited 650 patients, and data from 504 (252 per group) were analyzed after propensity score matching. In the pemafibrate group, both TG and HDL-C showed significant improvements (p < 0.001), and several indices reflecting TG-rich lipoproteins, low-density lipoprotein-cholesterol particle size, and liver enzyme elevations were significantly ameliorated compared with the control group, but there was no difference in glycemic control markers. One of the key secondary endpoints showed that switching from conventional fibrates to pemafibrate improved eGFR but increased uric acid concentration.

CONCLUSIONS

In patients with T2DM, pemafibrate has superior effects on lipid profile as well as liver and renal dysfunction to conventional fibrates.

Diabetic Kidney Disease: From Pathogenesis to Novel Treatment Possibilities

One of the microvascular complications of diabetes is diabetic kidney disease (DKD), often leading to end stage renal disease (ESRD) in which patients require costly dialysis or transplantation. The silent onset and irreversible progression of DKD are characterized by a steady decline of the estimated glomerular filtration rate, with or without concomitant albuminuria. The diabetic milieu allows the complex pathophysiology of DKD to enter a vicious cycle by inducing the synthesis of excessive amounts of reactive oxygen species (ROS) causing oxidative stress, inflammation, and fibrosis. As no cure is available, intensive research is required to develop novel treatments possibilities. This chapter provides an overview of the important pathomechanisms identified in diabetic kidney disease, the currently established therapies, as well as recently developed novel therapeutic strategies in DKD.

Management of Mild-to-Moderate Hypertriglyceridemia

OBJECTIVE

Hypertriglyceridemia is highly prevalent globally and its prevalence is rising with international increases in the incidence of obesity and diabetes. This review examines current management and future therapies METHODS: For this review, hypertriglyceridemia is defined as mild-to-moderate triglyceride elevation, a fasting or non-fasting triglyceride level >150 mg/dL and <500 mg/dL. We reviewed scientific studies published over the last 30 years and current professional society recommendations regarding evaluation and treatment of hypertriglyceridemia.

RESULTS

Genetics, lifestyle, and other environmental factors impact triglyceride levels. In adults with mild-to-moderate hypertriglyceridemia, clinicians should routinely assess and treat secondary treatable causes (diet, physical activity, obesity, metabolic syndrome, and reduction or cessation of medications that elevate triglyceride levels). Since atherosclerotic cardiovascular disease (ASCVD) risk is the primary clinical concern, statins are usually first-line treatment. Patients with triglyceride levels between >150 mg/dL and <500 mg/dL whose LDL-C is treated adequately with statins (at "maximally tolerated" doses, per some statements) and have either prior cardiovascular disease or diabetes mellitus plus at least 2 additional cardiovascular disease risk factors should be considered for added icosapent ethyl treatment to further reduce their cardiovascular disease risk. Fibrates, niacin, and other approved agents or agents under development are also reviewed in detail.

CONCLUSION

The treatment paradigm for mild-to-moderate hypertriglyceridemia is changing based on data from recent clinical trials. Recent trials suggest that the addition of icosapent ethyl to background statin therapy may further reduce ASCVD risk in patients with moderate HTG, though a particular TG goal has not been identified.

Fenofibrate and Heart Failure Outcomes in Patients With Type 2 Diabetes: Analysis From ACCORD

OBJECTIVE

Patients with type 2 diabetes (T2D) have a high risk for developing heart failure (HF), which is associated with poor prognosis. Fenofibrate may reduce HF events through multiple mechanisms. We sought to study the effect of fenofibrate (vs. placebo) in HF outcomes among patients with T2D receiving simvastatin enrolled in the Action to Control Cardiovascular Risk in Diabetes lipid trial (ACCORD Lipid).

RESEARCH DESIGN AND METHODS

We used Cox regression analysis with background glucose-lowering strategy as the stratification variable. The median follow-up was 4.7 years.

RESULTS

A total of 5,518 patients were included. Median age was 62 years, and 31% were women. Prior HF history was present in 5% of the patients. The composite outcome of HF hospitalization or cardiovascular death occurred in 190 (6.9%) patients in the fenofibrate group vs. 228 (8.3%) in the placebo group: HR 0.82, 95% CI 0.68-1.00 (P = 0.048). The beneficial effect of fenofibrate to reduce HF hospitalizations or cardiovascular death was present among patients receiving standard glucose-lowering strategy, HR 0.64, 95% CI 0.48-0.85, and not among patients receiving intensive glucose-lowering strategy, HR 1.02, 95% CI 0.79-1.33 (Pinteraction = 0.017). A similar pattern was observed for HF hospitalizations alone. The effect of fenofibrate on blood lipids was not influenced by background glucose-lowering therapy in a clinically important manner. Fenofibrate caused more transient worsening estimated glomerular filtration rate (eGFR) events but slowed long-term eGFR decline.

CONCLUSIONS

In patients with T2D treated with simvastatin, fenofibrate reduced the composite of HF hospitalizations or cardiovascular mortality, an effect that was seen predominantly in patients with standard background glucose-lowering therapy.

The 2021-2022 position of Brazilian Diabetes Society on diabetic kidney disease (DKD) management: an evidence-based guideline to clinical practice. Screening and treatment of hyperglycemia, arterial hypertension, and dyslipidemia in the patient with DKD

BACKGROUND

Diabetic kidney disease is the leading cause of end-stage renal disease and is associated with increased morbidity and mortality. This review is an authorized literal translation of part of the Brazilian Diabetes Society (SBD) Guidelines 2021-2022. This evidence-based guideline provides guidance on the correct management of Diabetic Kidney Disease (DKD) in clinical practice.

METHODS

The methodology was published elsewhere in previous SBD guidelines and was approved by the internal institutional Steering Committee for publication. Briefly, the Brazilian Diabetes Society indicated 14 experts to constitute the Central Committee, designed to regulate methodology, review the manuscripts, and make judgments on degrees of recommendations and levels of evidence. SBD Renal Disease Department drafted the manuscript selecting key clinical questions to make a narrative review using MEDLINE via PubMed, with the best evidence available including high-quality clinical trials, metanalysis, and large observational studies related to DKD diagnosis and treatment, by using the MeSH terms [diabetes], [type 2 diabetes], [type 1 diabetes] and [chronic kidney disease].

RESULTS

The extensive review of the literature made by the 14 members of the Central Committee defined 24 recommendations. Three levels of evidence were considered: A. Data from more than 1 randomized clinical trial or 1 metanalysis of randomized clinical trials with low heterogeneity (I2 < 40%). B. Data from metanalysis, including large observational studies, a single randomized clinical trial, or a pre-specified subgroup analysis. C: Data from small or non-randomized studies, exploratory analyses, or consensus of expert opinion. The degree of recommendation was obtained based on a poll sent to the panelists, using the following criteria: Grade I: when more than 90% of agreement; Grade IIa 75-89% of agreement; IIb 50-74% of agreement, and III, when most of the panelist recommends against a defined treatment.

CONCLUSIONS

To prevent or at least postpone the advanced stages of DKD with the associated cardiovascular complications, intensive glycemic and blood pressure control are required, as well as the use of renin-angiotensin-aldosterone system blocker agents such as ARB, ACEI, and MRA. Recently, SGLT2 inhibitors and GLP1 receptor agonists have been added to the therapeutic arsenal, with well-proven benefits regarding kidney protection and patients' survival.

Efficacy and Safety of K-877 (Pemafibrate), a Selective PPARα Modulator, in European Patients on Statin Therapy

OBJECTIVE

High plasma triglyceride (TG) is an independent risk factor for cardiovascular disease. Fibrates lower TG levels through peroxisome proliferator-activated receptor α (PPARα) agonism. Currently available fibrates, however, have relatively low selectivity for PPARα. The aim of this trial was to assess the safety, tolerability, and efficacy of K-877 (pemafibrate), a selective PPARα modulator, in statin-treated European patients with hypertriglyceridemia.

RESEARCH DESIGN AND METHODS

A total of 408 statin-treated adults were recruited from 68 European sites for this phase 2, randomized, double-blind, placebo-controlled trial. They had fasting TG between 175 and 500 mg/dL and HDL-cholesterol (HDL-C) ≤50 mg/dL for men and ≤55 mg/dL for women. Participants were randomly assigned to receive placebo or one of six pemafibrate regimens: 0.05 mg twice a day, 0.1 mg twice a day, 0.2 mg twice a day, 0.1 mg once daily, 0.2 mg once daily, or 0.4 mg once daily. The primary end points were TG and non-HDL-C level lowering at week 12.

RESULTS

Pemafibrate reduced TG at all doses (adjusted P value <0.001), with the greatest placebo-corrected reduction from baseline to week 12 observed in the 0.2-mg twice a day treatment group (54.4%). Reductions in non-HDL-C did not reach statistical significance. Reductions in TG were associated with improvements in other markers for TG-rich lipoprotein metabolism, including reductions in apoB48, apoCIII, and remnant cholesterol and an increase in HDL-C levels. Pemafibrate increased LDL-cholesterol levels, whereas apoB100 was unchanged. Pemafibrate was safe and well-tolerated, with only minor increases in serum creatinine and homocysteine concentrations.

CONCLUSIONS

Pemafibrate is effective, safe, and well-tolerated for the reduction of TG in European populations with hypertriglyceridemia despite statin treatment.

Mixed diabetic retinopathy screening coverage results in Indigenous Australian primary care settings: A nurse-led model of integrated diabetes care

AIMS

To determine eye screening coverage and adherence to national eye screening recommendations of a nurse-led retinal image-based model of diabetes education and eye screening in Indigenous primary care clinics.

DESIGN

A pre-post study.

METHODS

During January 2018-March 2020 Indigenous Australians with diabetes at three regional Australian clinics were offered eye screening by a nurse-diabetes educator/retinal imager. At the main site the nurse recruited/scheduled participants, and at satellite sites local clinic staff did so. Visual acuity was tested and digital retinal images acquired and graded. Participants were offered rescreening at or before 12-months based on baseline results.

RESULTS

In total 203 adults with diabetes attending Indigenous primary care clinics were screened, with divergent results based on the recruitment methods. At the main clinic 135 of 172 eligible adults (79%) were screened. At the satellite sites, 15 of 85 (18%) and 21 of 77 (27%) diabetes patients were screened. Combined coverage 51%.

CONCLUSION

A credentialed nurse-educator implemented a model of retinal image-based diabetes education, measured eye screening coverage and adherence to national eye screening guidelines, met the 'acceptable 75% eye screening coverage' benchmark and improved patient eye screening guideline adherence at the one site where the nurse-educator had access to patient recruitment and scheduling.

IMPACT

This novel nurse-led primary care iDEES model of retinal image-based diabetes education can improve the currently low Indigenous diabetes eye screening coverage in Australia. Importantly, the nurse-managed iDEES model of integrated diabetes care is readily adaptable to other settings and populations where access to and/or uptake of eye care is suboptimal.

CLINICAL TRIAL REGISTRATION

ANZCTRN1261800120435.

The Effect of Fibrates on Kidney Function and Chronic Kidney Disease Progression: A Systematic Review and Meta-Analysis of Randomised Studies

AIM

Fibrates have proven efficacy in cardiovascular risk reduction and are commonly used, in addition to statins, to control hypertriglyceridaemia. Their use is often limited due to reduction in glomerular filtration rate at treatment initiation. However, recent studies suggest benign changes in kidney function and improvement of proteinuria, an established early marker of microvascular disease and kidney disease progression. We summarize the evidence from existing trials and provide a summary of effects of fibrates, alone or in combination, on kidney disease progression and proteinuria.

METHODS AND RESULTS

Systematic review and meta-analysis of randomized, controlled trials (PROSPERO CRD42020187764). Out of 12,243 potentially eligible studies, 29 were included in qualitative and quantitative analysis, with a total of 20,176 patients. Mean creatinine increased by 1.05 (95% CI (0.63 to 1.46)) units in patients receiving fibrates vs. comparator, and this was similar in all other subgroups. eGFR showed a bigger decrease in the fibrates arm (SMD -1.99; 95% CI (-3.49 to -0.48)) when all studies were pooled together. Notably, short-term serum creatinine and eGFR changes remained constant in the long-term. Pooled estimates show that fibrates improve albuminuria progression, RR 0.86; 95% CI (0.76 to 0.98); albuminuria regression, RR 1.19; 95% CI (1.08 to 1.310).

CONCLUSIONS

Fibrates improve albuminuria in patients with and without diabetes when used to treat hyperlipidaemia. The modest creatinine increase should not be a limiting factor for fibrate initiation in people with preserved renal function or mild CKD. The long-term effects on kidney disease progression warrant further study.

Medications Activating Tubular Fatty Acid Oxidation Enhance the Protective Effects of Roux-en-Y Gastric Bypass Surgery in a Rat Model of Early Diabetic Kidney Disease

Background

Roux-en-Y gastric bypass surgery (RYGB) improves biochemical and histological parameters of diabetic kidney disease (DKD). Targeted adjunct medical therapy may enhance renoprotection following RYGB.

Methods

The effects of RYGB and RYGB plus fenofibrate, metformin, ramipril, and rosuvastatin (RYGB-FMRR) on metabolic control and histological and ultrastructural indices of glomerular and proximal tubular injury were compared in the Zucker Diabetic Sprague Dawley (ZDSD) rat model of DKD. Renal cortical transcriptomic (RNA-sequencing) and urinary metabolomic (1H-NMR spectroscopy) responses were profiled and integrated. Transcripts were assigned to kidney cell types through in silico deconvolution in kidney single-nucleus RNA-sequencing and microdissected tubular epithelial cell proteomics datasets. Medication-specific transcriptomic responses following RYGB-FMRR were explored using a network pharmacology approach. Omic correlates of improvements in structural and ultrastructural indices of renal injury were defined using a molecular morphometric approach.

Results

RYGB-FMRR was superior to RYGB alone with respect to metabolic control, albuminuria, and histological and ultrastructural indices of glomerular injury. RYGB-FMRR reversed DKD-associated changes in mitochondrial morphology in the proximal tubule to a greater extent than RYGB. Attenuation of transcriptomic pathway level activation of pro-fibrotic responses was greater after RYGB-FMRR than RYGB. Fenofibrate was found to be the principal medication effector of gene expression changes following RYGB-FMRR, which led to the transcriptional induction of PPARα-regulated genes that are predominantly expressed in the proximal tubule and which regulate peroxisomal and mitochondrial fatty acid oxidation (FAO). After omics integration, expression of these FAO transcripts positively correlated with urinary levels of PPARα-regulated nicotinamide metabolites and negatively correlated with urinary tricarboxylic acid (TCA) cycle intermediates. Changes in FAO transcripts and nicotinamide and TCA cycle metabolites following RYGB-FMRR correlated strongly with improvements in glomerular and proximal tubular injury.

Conclusions

Integrative multi-omic analyses point to PPARα-stimulated FAO in the proximal tubule as a dominant effector of treatment response to combined surgical and medical therapy in experimental DKD. Synergism between RYGB and pharmacological stimulation of FAO represents a promising combinatorial approach to the treatment of DKD in the setting of obesity.

Uric Acid and Impairment of Renal Function in Non-diabetic Hypertensive Patients

Hyperuricemia is a risk factor for renal impairment. However, investigations focusing on patients with hypertension are limited and inconsistent. A single-center prospective cohort study of 411 Han Chinese non-diabetic hypertensive patients was conducted in Taiwan. The mean age of the participants was 62.0 ±14.4 years. The baseline estimated glomerular filtration rate and uric acid level were 86 mL/min/1.73 m² and 6.2 mg/dL, respectively. All patients underwent serum biochemistry tests for creatinine levels every 3 months. Renal events were defined as >25% and >50% decline in estimated glomerular filtration rate. During an average follow-up period of 4.7 ± 2.9 years (median 4.0 years), a >25 and >50% decline in estimated glomerular filtration rate was noted in 52 and 11 patients, respectively. The multivariate Cox regression analysis revealed that a baseline uric acid level ≥8.0 mg/dL increased the risk of >25% decline (hazard ratio: 3.541; 95% confidence interval: 1.655–7.574, P = 0.001) and >50% decline (hazard ratio: 6.995; 95% confidence interval: 1.309–37.385, P = 0.023) in estimated glomerular filtration rate. Similarly, a baseline uric acid level ≥7.5 mg/dL was independently associated with >25% decline (hazard ratio: 2.789; 95% confidence interval: 1.399–5.560, P = 0.004) and >50% decline (hazard ratio: 6.653; 95% confidence interval: 1.395–31.737, P = 0.017). However, this was not demonstrated at baseline uric acid level ≥7.0 mg/dL. Our study suggests that hyperuricemia is an independent risk factor for the decline in renal function in patients with hypertension. Uric acid level ≥7.5 mg/dL may be considered as the optimal cutoff value for clinical practice in predicting the development of renal impairment.

The Association of Postprandial Triglyceride Variability with Renal Dysfunction and Microalbuminuria in Patients with Type 2 Diabetic Mellitus: A Retrospective and Observational Study

OBJECTIVE

We examined whether or not day-to-day variations in lipid profiles, especially triglyceride (TG) variability, were associated with the exacerbation of diabetic kidney disease.

METHODS

We conducted a retrospective and observational study. First, 527 patients with type 2 diabetes mellitus (DM) who had had their estimated glomerular filtration rate (eGFR) checked every 6 months since 2012 for over 5 years were registered. Variability in postprandial TG was determined using the standard deviation (SD), SD adjusted (Adj-SD) for the number of measurements, and maximum minus minimum difference (MMD) during the first three years of follow-up. The endpoint was a ≥40% decline from baseline in the eGFR, initiation of dialysis or death. Next, 181 patients who had no micro- or macroalbuminuria in February 2013 were selected from among the 527 patients for an analysis. The endpoint was the incidence of microalbuminuria, initiation of dialysis, or death.

RESULTS

Among the 527 participants, 110 reached a ≥40% decline from baseline in the eGFR or death. The renal survival was lower in the higher-SD, higher-Adj-SD, and higher-MMD groups than in the lower-SD, lower-Adj-SD, and lower-MMD groups, respectively (log-rank test p = 0.0073, 0.0059, and 0.0195, respectively). A lower SD, lower Adj-SD, and lower MMD were significantly associated with the renal survival in the adjusted model (hazard ratio, 1.62, 1.66, 1.59; 95% confidence intervals, 1.05-2.53, 1.08-2.58, 1.04-2.47, respectively). Next, among 181 participants, 108 developed microalbuminuria or death. The nonincidence of microalbuminuria was lower in the higher-SD, higher-Adj-SD, and higher-MMD groups than in the lower-SD, lower-Adj-SD, and lower-MMD groups, respectively (log-rank test p = 0.0241, 0.0352, and 0.0474, respectively).

CONCLUSIONS

Postprandial TG variability is a novel risk factor for eGFR decline and the incidence of microalbuminuria in patients with type 2 DM.

Novel Therapies for Kidney Disease in People With Diabetes

CONTEXT

The increasing burden of diabetic kidney disease (DKD) has led to the discovery of novel therapies.

OBJECTIVE

This review aims to summarize the results of recent clinical trials that test the efficacy of potential therapies for DKD.

METHODS

A systematized narrative review was performed utilizing the PubMed, Embase (Ovid), CINAHL, and Cochrane databases (January 2010 to January 2021). The included trials assessed the efficacy of specific medications using renal endpoints in adult participants with type 1 or 2 diabetes.

RESULTS

Fifty-three trials were identified. Large, multinational, and high-powered trials investigating sodium-glucose cotransporter 2 (SGLT2) inhibitors demonstrated improved renal outcomes, even in patients with established DKD. Trials examining incretin-related therapies also showed some improvement in renal outcomes. Additionally, mineralocorticoid receptor antagonists exhibited potential with multiple improved renal outcomes in large trials, including those involving participants with established DKD. Atrasentan, baricitinib, ASP8232, PF-04634817, CCX140-B, atorvastatin, fenofibrate, probucol, doxycycline, vitamin D, omega-3 fatty acids, silymarin, turmeric, total glucosides of paeony, and tripterygium wilfordii Hook F extract were all associated with some improved renal endpoints but need further exploration. While bardoxolone methyl was associated with a decrease in albuminuria, high rates of cardiovascular adverse effects curtailed further exploration into this agent. Selonsertib, allopurinol, praliciguat, palosuran, benfotiamine, and diacerein were not associated with improved renal outcomes.

CONCLUSION

Trials have yielded promising results in the search for new therapies to manage DKD. SGLT2 inhibitors and incretin-related therapies have demonstrated benefit and were associated with improved cardiovascular outcomes. Mineralocorticoid receptor antagonists are another class of agents with increasing evidence of benefits.

Lipidomic approaches to dissect dysregulated lipid metabolism in kidney disease

Dyslipidaemia is a hallmark of chronic kidney disease (CKD). The severity of dyslipidaemia not only correlates with CKD stage but is also associated with CKD-associated cardiovascular disease and mortality. Understanding how lipids are dysregulated in CKD is, however, challenging owing to the incredible diversity of lipid structures. CKD-associated dyslipidaemia occurs as a consequence of complex interactions between genetic, environmental and kidney-specific factors, which to understand, requires an appreciation of perturbations in the underlying network of genes, proteins and lipids. Modern lipidomic technologies attempt to systematically identify and quantify lipid species from biological systems. The rapid development of a variety of analytical platforms based on mass spectrometry has enabled the identification of complex lipids at great precision and depth. Insights from lipidomics studies to date suggest that the overall architecture of free fatty acid partitioning between fatty acid oxidation and complex lipid fatty acid composition is an important driver of CKD progression. Available evidence suggests that CKD progression is associated with metabolic inflexibility, reflecting a diminished capacity to utilize free fatty acids through β-oxidation, and resulting in the diversion of accumulating fatty acids to complex lipids such as triglycerides. This effect is reversed with interventions that improve kidney health, suggesting that targeting of lipid abnormalities could be beneficial in preventing CKD progression.

OUP accepted manuscript

Autosomal dominant polycystic kidney disease (ADPKD) is the most prevalent hereditary kidney disease. Recent evidence suggests that the pathogenesis of ADPKD is a complex web of abnormal cellular processes including altered cell signaling, disordered cell metabolism, impaired autophagy, increased apoptosis, mitochondrial dysfunction and chronic inflammation. Sodium–glucose cotransporter (SGLT) inhibitors (SGLTi) reduce body weight, blood pressure and blood glucose levels, have kidney and cardiovascular protective activity, and have been reported to decrease inflammation, increase autophagy and improve mitochondrial dysfunction. We now review results from preclinical studies on SGLTi for ADPKD identified through a systematic search of the MEDLINE, Cochrane Library, Embase and PubMed databases. Potential underlying mechanisms for the conflicting results reported as well as implications for clinical translation are discussed, as ADPKD patients were excluded from clinical trials exploring kidney protection by SGLT2 inhibitors (SGLT2i). However, they were not excluded from cardiovascular safety trials or trials for cardiovascular conditions. A post-hoc analysis of the kidney function trajectories and safety of SGLT2i in ADPKD patients enrolled in such trials may provide additional information. In conclusion, SGLT2i are cardio- and nephroprotective in diverse clinical situations. Currently, it is unclear whether ADPKD patients may benefit from SGLT2i in terms of kidney function preservation, and their safety in this population remains unexplored. We propose a roadmap to address this unmet clinical need.

Epidemiological characteristics of diabetic kidney disease in Taiwan

Diabetic kidney disease (DKD) is a critical microvascular complication of diabetes. With the continuous increase in the prevalence of diabetes since 2000, the prevalence of DKD has also been increasing in past years. The prevalence of DKD among individuals with type 2 diabetes in Taiwan increased from 13.32% in 2000 to 17.92% in 2014. The cumulative incidence of DKD among individuals with type 1 diabetes in Taiwan was higher than 30% during 1999-2012. DKD is the leading cause of end-stage renal disease (ESRD), with a prevalence of approximately 45% in a population on chronic dialysis in Taiwan. Among individuals with type 2 diabetes, the prevalence of ESRD in the receipt of dialysis also increased from 1.32% in 2005 to 1.47% in 2014. Risk factors for DKD development are age, race, family history, hyperglycemia, hypertension, dyslipidemia, dietary patterns, and lifestyles. Prognostic factors that aggravate DKD progression include age, family history, sex, glycemic control, blood pressure (BP), microvascular complications, and atherosclerosis. This review summarizes updated information on the onset and progression of DKD, particularly in the Taiwanese population. Translating these epidemiological features is essential to optimizing the kidney care and improving the prognosis of DKD in Asian populations.

Protocol for a preclinical systematic review and meta-analysis of pharmacological targeting of peroxisome proliferator-activated receptors in experimental renal injury

INTRODUCTION

Impaired lipid metabolism in the renal tubule plays a prominent role in the progression of renal fibrosis following acute kidney injury (AKI) and in chronic kidney disease (CKD). Peroxisome proliferator-activated receptors (PPARs) are promising druggable targets to mitigate renal fibrosis by redirecting metabolism, including restoration of fatty acid oxidation (FAO) capacity. We aim to synthesise evidence from preclinical studies of pharmacological PPAR targeting in experimental renal injury, and inform the design of future studies evaluating PPAR-mediated restoration of FAO in AKI and CKD.

METHODS AND ANALYSIS

Studies reporting on the impact of pharmacological PPAR modulation in animal models of renal injury will be collected from MEDLINE (Ovid), Embase and Web of Science databases. Predefined eligibility criteria will exclude studies testing medications which are not specific ligands of one or more PPARs and studies involving multimodal pharmacological treatment. The Systematic Review Centre for Laboratory Animal Experimentation risk of bias tool and Collaborative Approach to Meta-Analysis and Review of Animal Experimental Studies checklist will be used to assess quality of the included studies. Data extraction will be followed by a narrative synthesis of the data and meta-analysis where feasible. Analysis will be performed separately for AKI, CKD and renal transplant models. Subgroup analyses will be performed based on study design characteristics, PPAR isotype(s) targeted, and classes of PPAR-targeting medications used. Risk of publication bias will be assessed using funnel plotting, Egger's regression and trim-and-fill analysis.

ETHICS AND DISSEMINATION

Ethical approval is not required. Findings will be published in a peer-reviewed journal and presented at scientific meetings.

PROSPERO REGISTRATION NUMBER

CRD42021265550.

Trajectories of kidney function in diabetes: a clinicopathological update

Diabetic nephropathy has been traditionally diagnosed based on persistently high albuminuria and a subsequent decline in glomerular filtration rate (GFR), which is widely recognized as the classical phenotype of diabetic kidney disease (DKD). Several studies have emphasized that trajectories of kidney function in patients with diabetes (specifically, changes in GFR and albuminuria over time) can differ from this classical DKD phenotype. Three alternative DKD phenotypes have been reported to date and are characterized by albuminuria regression, a rapid decline in GFR, or non-proteinuric or non-albuminuric DKD. Although kidney biopsies are not typically required for the diagnosis of DKD, a few studies of biopsy samples from patients with DKD have demonstrated that changes in kidney function associate with specific histopathological findings in diabetes. In addition, various clinical and biochemical parameters are related to trajectories of GFR and albuminuria. Collectively, pathological and clinical characteristics can be used to predict trajectories of GFR and albuminuria in diabetes. Furthermore, cohort studies have suggested that the risks of kidney and cardiovascular outcomes might vary among different phenotypes of DKD. A broader understanding of the clinical course of DKD is therefore crucial to improve risk stratification and enable early interventions that prevent adverse outcomes.

Relationship of low molecular weight fluorophore levels with clinical factors and fenofibrate effects in adults with type 2 diabetes

People with diabetes are at risk of chronic complications and novel biomarkers, such as Advanced glycation end-products (AGEs) may help stratify this risk. We assessed whether plasma low-molecular weight AGEs, also known as LMW-fluorophores (LMW-F), are associated with risk factors, predict complications, and are altered by fenofibrate in adults with type 2 diabetes. Plasma LMW-F were quantified at baseline, after six weeks fenofibrate, and one year post-randomisation to fenofibrate or placebo. LMW-F associations with existing and new composite vascular complications were determined, and effects of fenofibrate assessed. LMW-F correlated positively with age, glycated haemoglobin (HbA1c), pulse pressure, kidney dysfunction and inflammation; and negatively with urate, body mass index, oxidative stress and leptin, albeit weakly (r = 0.04–0.16, all p < 0.01). Independent determinants of LMW-F included smoking, diastolic blood pressure, prior cardiovascular disease or microvascular complications, Caucasian ethnicity, kidney function, HbA1c and diabetes duration (all p ≤ 0.01). Baseline LMW-F tertiles correlated with on-trial macrovascular and microvascular complications (trend p < 0.001) on univariate analyses only. Six weeks of fenofibrate increased LMW-F levels by 21% (p < 0.001). In conclusion, LMW-F levels correlate with many risk factors and chronic diabetes complications, and are increased with fenofibrate. LMW-F tertiles predict complications, but not independently of traditional risk factors.

Efficacy and Safety of Fenofibrate-Statin Combination Therapy in Patients With Inadequately Controlled Triglyceride Levels Despite Previous Statin Monotherapy: A Multicenter, Randomized, Double-blind, Phase IV Study

PURPOSE

Residual cardiovascular risk reduction by fenofibrate in patients with high serum triglyceride (TG) levels despite previous statin monotherapy is not well characterized. The purpose of this study was to evaluate the efficacy and safety of a combination of choline fenofibrate and statin in patients with inadequately controlled TG levels despite previous statin monotherapy.

METHODS

This prospective, multicenter, randomized, double-blind study was conducted in Korea. A total of 133 patients with controlled LDL-C but elevated TG levels, already receiving statin monotherapy, were enrolled in the study, which was conducted from July 2018 to December 2019. Patients were randomly assigned to receive combination therapy with choline fenofibrate and statin or statin monotherapy in a 1:1 ratio. After 8 weeks of treatment, the lipid profiles and safety parameters of the patients in the 2 groups were compared.

FINDINGS

The study included 127 patients (64 in the combination group and 63 in the control group) older than 19 years. After 8 weeks of therapy, mean serum TG levels significantly decreased from 269.8 to 145.5 mg/dL (P < 0.0001) in the combination therapy group, whereas no significant changes occurred in the statin monotherapy group (from 271.1 to 280.5 mg/dL). Contrarily, the mean serum HDLC levels significantly increased from 45.0 to 50.4 mg/dL (P = 0.0004) in the combination therapy group, whereas there were no significant changes in the monotherapy group (from 44.3 to 44.7 mg/dL). There were no additional serious adverse events in the combination therapy group compared with the statin monotherapy group.

IMPLICATIONS

The combination therapy using choline fenofibrate and statin was found to be effective in serum TG control and likely tolerable in patients with high TG levels despite statin monotherapy. A larger study, conducted for a longer duration, is needed to evaluate the effectiveness of this combination in reducing cardiovascular risk. ClinicalTrials.gov identifier: NCT03874260.

The Loss of Mitochondrial Quality Control in Diabetic Kidney Disease

Diabetic kidney disease (DKD) is the predominant complication of diabetes mellitus (DM) and the leading cause of chronic kidney disease and end-stage renal disease worldwide, which are major risk factors for death. The pathogenesis of DKD is very complicated, including inflammation, autophagy impairment, oxidative stress, and so on. Recently, accumulating evidence suggests that the loss of mitochondrial quality control exerts critical roles in the progression of DKD. Mitochondria are essential for eukaryotic cell viability but are extremely vulnerable to damage. The mechanisms of mitochondrial quality control act at the molecular level and the organelle level, including mitochondrial dynamics (fusion and fission), mitophagy, mitochondrial biogenesis, and mitochondrial protein quality control. In this review, we summarize current knowledge of the role of disturbances in mitochondrial quality control in the pathogenesis of DKD and provide potential insights to explore how to delay the onset and development of DKD.

Diabetic kidney disease in patients with type 2 diabetes mellitus: a cross-sectional study

Aim

Diabetic kidney disease (DKD) is a major long-term complication of diabetes mellitus (DM). Given the paucity of data on DKD in Jordan, we aimed to evaluate the prevalence, characteristics and correlates of DKD in Jordanian patients with type 2 DM.

Methods

This cross-sectional study included 1398 adult patients with type 2 DM who sought medical advice in the endocrinology clinic between March and September 2019. Demographic, clinical and laboratory data were reviewed. DKD was defined as reduced eGFR, and/or albuminuria. Three regression models were constructed to identify factors associated with CKD stages, albuminuria and DKD.

Results

Overall, 701 (50.14%) patients had DKD, with a median age of 59.71 ± 11.36  years. Older age, high triglycerides, and low high-density lipoprotein were associated with DKD (multivariable odds ratio [OR]: 1.02, 95% confidence interval [CI]: 1.01–1.03, p < 0.01; OR: 1.1, 95% CI: 1.01–1.2; and OR: 0.98, 95% CI: 0.97–0.99, p < 0.01 respectively). Metformin and renin-angiotensin system blockers were negatively associated with albuminuria and chronic kidney disease stages (p < 0.01).

Conclusion

Our study demonstrated that approximately one half of patients with type 2 DM had DKD. Further studies are necessary to understand this high prevalence and the underlying factors. Future research are needed to assess implementing targeted community-based intervention.

Pemafibrate Protects against Fatty Acid-Induced Nephropathy by Maintaining Renal Fatty Acid Metabolism

As classical agonists for peroxisomal proliferator-activated receptor alpha (PPARα), fibrates activate renal fatty acid metabolism (FAM) and provide renoprotection. However, fibrate prescription is limited in patients with kidney disease, since impaired urinary excretion of the drug causes serious adverse effects. Pemafibrate (PEM), a novel selective PPARα modulator, is mainly excreted in bile, and, thus, may be safe and effective in kidney disease patients. It remains unclear, however, whether PEM actually exhibits renoprotective properties. We investigated this issue using mice with fatty acid overload nephropathy (FAON). PEM (0.5 mg/kg body weight/day) or a vehicle was administered for 20 days to 13-week-old wild-type male mice, which were simultaneously injected with free fatty acid (FFA)-binding bovine serum albumin from day 7 to day 20 to induce FAON. All mice were sacrificed on day 20 for assessment of the renoprotective effect of PEM against FAON. PEM significantly attenuated the histological findings of tubular injury caused by FAON, increased the renal expressions of mRNA and proteins related to FAM, and decreased renal FFA content and oxidative stress. Taken together, PEM exhibits renoprotective effects through the activation and maintenance of renal FAM and represents a promising drug for kidney disease.

Efficacy of a micronized, nanocrystal fenofibrate formulation in treatment of hyperlipidemia in dogs

Background

Safe, effective, and readily available drug therapies are required for the management of hyperlipidemia and its associated complications in dogs.

Objectives

To investigate the efficacy of a micronized, nanocrystal formulation of fenofibrate (Tricor) in the treatment of hyperlipidemia in dogs.

Animals

Ten client‐owned dogs with primary (n = 7) and secondary (n = 3) hyperlipidemia. All dogs had hypertriglyceridemia at baseline; 3 dogs also had hypercholesterolemia.

Methods

Prospective dose‐escalation study. Dogs were treated with fenofibrate orally once daily in up to 3 cycles of 21 days each. Fenofibrate dose was increased at the end of each cycle if hypertriglyceridemia persisted and adverse effects were not documented. Complete blood count, biochemistry, and urine protein:creatinine ratio were collected serially. Baseline (T0) parameters were compared to time of maximal reduction in serum triglyceride concentrations (T1) and reported as median (range).

Results

Triglycerides normalized in all dogs (T0 = 662 mg/dL [189‐2391]; T1 = 113 mg/dL [81‐132]; P = .002). Fenofibrate dose at T1 = 6.4 mg/kg PO q24h (range, 2.2‐13.5). T1 was achieved at 3 (n = 4), 6 (n = 4), and 9 (n = 2) weeks. Serum cholesterol concentrations decreased in 9 of 10 dogs. Quiet demeanor and firm stools in 1 dog were the only reported adverse reactions. Fenofibrate administration resulted in a significant reduction in median alkaline phosphatase activity (P = .049).

Conclusions and Clinical Importance

Over 21 to 63 days, TriCor was effective in the management of primary and secondary hyperlipidemia in dogs.

Diabetic kidney disease in type 2 diabetes: a review of pathogenic mechanisms, patient-related factors and therapeutic options

The global prevalence of diabetic kidney disease is rapidly accelerating due to an increasing number of people living with type 2 diabetes. It has become a significant global problem, increasing human and financial pressures on already overburdened healthcare systems. Interest in diabetic kidney disease has increased over the last decade and progress has been made in determining the pathogenic mechanisms and patient-related factors involved in the development and pathogenesis of this disease. A greater understanding of these factors will catalyse the development of novel treatments and influence current practice. This review summarises the latest evidence for the factors involved in the development and progression of diabetic kidney disease, which will inform better management strategies targeting such factors to improve therapeutic outcomes in patients living with diabetes.

Fenofibrate Delays the Need for Dialysis and Reduces Cardiovascular Risk Among Patients With Advanced CKD

CONTEXT

Fenofibrate provides limited cardiovascular (CV) benefits in the general population; however, little is known about its benefit among advanced chronic kidney disease (CKD) patients.

OBJECTIVE

This study compared outcomes among advanced CKD patients treated with fenofibrate, statins, a combination of both, and none of these.

METHODS

This national cohort study was based on Taiwan's National Health Insurance Research Database. Patients younger than 20 years with advanced CKD were identified and further divided into 4 groups according to treatment. The inverse probability of treatment weighting was used to balance baseline characteristics. Patients received fenofibrate, statins, a combination of fenofibrate and statins, or none of these in the 3 months preceding the advanced CKD date. Main outcome measures included all-cause mortality, CV death, and incidence of permanent dialysis.

RESULTS

The fenofibrate and statin groups exhibited a lower risk of CV death (fenofibrate vs nonuser: hazard ratio [HR]: 0.84; 95% CI, 0.75-0.94; statins vs nonuser: HR: 0.94; 95% CI, 0.90-0.97) compared with the nonuser group. The fenofibrate group further exhibited the lowest incidence of permanent dialysis (fenofibrate vs nonuser: subdistribution HR [SHR]: 0.78; 95% CI, 0.77-0.80; statins vs fenofibrate: SHR: 1.27; 95% CI, 1.26-1.29; combination vs fenofibrate: SHR: 1.15; 95% CI, 1.13-1.17). Furthermore, the combined administration of fenofibrate and high-intensity statins exhibited a lower risk of major adverse cardiac and cerebrovascular events.

CONCLUSION

For patients with advanced CKD, continuing fenofibrate may provide a protective effect on CV outcomes equal to that of statins, and it may further delay the need for permanent dialysis. The combination of fenofibrate and high-intensity statins may have additional benefits.

Potential Therapeutic Targets of Obesity-Related Glomerulopathy

The global increase of obesity parallels the obesity-related glomerulopathy (ORG) epidemic. The purpose of this review is to emphasize the potential therapeutic targets of ORG as well as the corresponding possible mechanisms. We systematically identified surveys, reports, and published studies that included data for the purpose of this review and did literature analysis. Under circumstance of obesity, weight loss, and renin-angiotensin-aldosterone blockade are the most studied therapies, effective to induce antiproteinuric effects and reversal of hyperfiltration in ORG. Glucagon-like peptide-1-based therapies led to improvement in proteinuria. Newer therapies directed to lipid metabolism, including farnesoid X receptor and takeda G protein-coupled receptor 5 agonists, peroxisome proliferator-activated receptor α agonists, hold therapeutic promise. Prevention and treatments of obesity and ORG are of great importance.