Long-term hemodynamic and molecular effects persist after discontinued renin–angiotensin system blockade in patients with type 1 diabetes mellitus

Efficacy of renin-angiotensin system inhibitors, calcium channel blockers, and diuretics in hypertensive patients with diabetes: subgroup analysis based on albuminuria in a systematic review and meta-analysis

In hypertensive patients with diabetes, the effectiveness of renin-angiotensin system (RAS) inhibitors in improving mortality, cardiovascular events, and renal outcomes, compared to other antihypertensive drugs such as calcium channel blockers (CCBs) and diuretics, remains uncertain, particularly in the context of albuminuria. A comprehensive literature search was conducted using PubMed, the Cochrane Library, and the Japan Medical Abstracts Society databases up to October 2024. A meta-analysis of 12 randomized controlled trials, including 14,163 patients, was performed. RAS inhibitors showed no significant advantage over CCBs or diuretics for all-cause mortality (relative risk [RR]: 1.00, 95% confidence interval [CI]: 0.92-1.08, p = 0.98), myocardial infarction (RR: 0.64, 95% CI: 0.32-1.31, p = 0.22), stroke (RR: 1.14, 95% CI: 1.00-1.31, p = 0.05), composite cardiovascular events (RR: 0.93, 95% CI: 0.81-1.07, p = 0.45), or end-stage renal disease (RR: 0.88, 95% CI: 0.72-1.08, p = 0.21). Subgroup analyses stratified by albuminuria status revealed no significant benefits of RAS inhibitors, regardless of albuminuria presence. The findings emphasize the need for cautious interpretation due to limited sample sizes, wide confidence intervals, and low precision. These results highlight the importance of considering not only RAS inhibitors but also other antihypertensive drugs as the first-line choice for blood pressure control in diabetic patients, with careful attention to side effects and other relevant factors.

Downregulation of Salusin-β protects renal tubular epithelial cells against high glucose-induced inflammation, oxidative stress, apoptosis and lipid accumulation via suppressing miR-155-5p

Diabetic nephropathy (DN) is the main contributor to the excess mortality for patients suffering from diabetes. Here, C57BL/6 mice received 4 weeks of high-fat diet and intraperitoneal injection of STZ (100 mg/kg). Mice with random blood glucose level ≥16.7 mmol/L and positive urine protein were recognized as successful DN model. To construct an in vitro model, HK-2 cells were incubated with 30 mM glucose. RT-qPCR and western blot were employed to measure Salusin-β levels in kidney tissues of DN mice and HG-induced HK-2 cells. Meanwhile, RT-qPCR was performed to detect miR-155-5p level in kidney tissues of DN mice and HG-induced HK-2 cells. TNF-α, IL-6, IL-1β, ROS, SOD and CAT levels were assessed using commercial assay kits. Furthermore, apoptosis of HK-2 cells was assessed via flow cytometric analysis and TUNEL staining. In addition, intracellular lipid accumulation and total cholesterol levels were detected using Oil red O staining and TC ELISA kit. Herein, Salusin-β and miR-155-5p levels were distinctly upregulated in kidney tissues of DN mice and HG-induced HK-2 cells. Downregulation of Salusin-β reduced miR-155-5p expression. Salusin-β silencing dramatically relieved inflammatory and oxidative injury, suppressed apoptosis as well as lipid accumulation induced by HG in HK-2 cells. Besides, miR-155-5p elevation partially abrogated the alleviating effects Salusin-β silencing on HG-induced RTEC injury. In summary, downregulation of Salusin-β protected HK-2 cells against HG-induced inflammation, oxidative stress, apoptosis and ameliorated lipid accumulation through suppressing miR-155-5p, which indicated that Salusin-β could be a potential therapeutic drug for DN.

Relationships between inflammation, hemodynamic function and RAAS in longstanding type 1 diabetes and diabetic kidney disease

The renin angiotensin aldosterone system (RAAS) is associated with renal disease and inflammation in a diabetes setting, however, little is known about the implicated mechanisms in individuals with long standing diabetes. Accordingly, our aim was to perform an observational study to quantify urinary excretion of inflammatory biomarkers in participants with long standing type 1 diabetes (T1D) (with and without diabetic kidney disease [DKD]) and controls, at baseline and in response to RAAS activation. GFR_INULIN, ERPF_PAH, and 42 urine inflammatory biomarkers were measured in 74 participants with T1D for ≥50 years (21 with DKD and 44 without DKD [DKD resistors]) and 73 healthy controls. Additionally, inflammatory biomarkers were measured before and after an angiotensin II infusion (ANGII, 1 ng∙kg^-1∙min^-1). Significantly lower urinary excretion of cytokines (IL-18, IL-1RA, IL-8), chemokines (MCP1, RANTES) and growth factors (TGF-α, PDGFAA, PDGFBB, VEGF-A) was observed in participants with T1D at baseline compared to controls. Urinary IL-6 was higher in DKD than in DKD resistors in an exploratory analysis unadjusted for multiple comparisons. In T1D only, lower GFR_INULIN correlated with greater excretion of proinflammatory biomarkers (IL-18, IP-10, & RANTES), growth factors (PDGF-AA & VEGFAA), and chemokines (eotaxin & MCP-1). ANGII increased 31 of 42 inflammatory biomarkers in T1D vs controls (p < 0.05), regardless of DKD resistor status. In conclusion, lower GFR and intra-renal RAAS activation were associated with increased inflammation even after longstanding T1D. The increased urinary IL-6 in patients with DKD requires further investigation to determine whether IL-6 is a candidate protective biomarker for prognostication or targeted therapy in DKD.

Retinopathy and RAAS Activation: Results From the Canadian Study of Longevity in Type 1 Diabetes

OBJECTIVE

The importance of renin-angiotensin-aldosterone system (RAAS) activation in retinopathy for long-standing diabetes is not well understood. We determined retinopathy stage and evaluated associations with other vascular complications before and after physiological RAAS activation in adults with long-standing (≥50 years duration) type 1 diabetes.

RESEARCH DESIGN AND METHODS

Participants underwent retinal examination by digital funduscopic photography and optical coherence tomography and were classified as having nonproliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), or no diabetic retinopathy (NDR) with or without diabetic macular edema (DME). Neuropathy was measured by clinical neuropathy examination scores, electrophysiologically, and by corneal confocal microscopy. Renal function was measured by inulin and para-aminohippurate clearance methods. Arterial stiffness was measured by applanation tonometry. Renal function, blood pressure, and arterial stiffness were measured before and after RAAS activation with angiotensin II (ANGII). Associations were determined using linear regression.

RESULTS

Twelve (16%) of the 75 participants had NDR, 24 (32%) had NPDR, and 39 (52%) had PDR. A low overall prevalence of DME (4%) was observed. Those with PDR had worse nerve function and reduced corneal nerve density, were more likely to have macrovascular disease, and had increased arterial stiffness in response to ANGII compared with those with NPDR or NDR. Prevalence of kidney disease or renal hemodynamic function did not differ by retinopathy status.

CONCLUSIONS

PDR was associated with neuropathy severity and cardiovascular and peripheral vascular disease. In those with PDR, RAAS activation may be linked to vascular stiffening, an effect that persists in long-standing type 1 diabetes.

Long-term Effect of Losartan on Kidney Disease in American Indians With Type 2 Diabetes: A Follow-up Analysis of a Randomized Clinical Trial

OBJECTIVE

To determine whether early administration of losartan slows progression of diabetic kidney disease over an extended period.

RESEARCH DESIGN AND METHODS

We conducted a 6-year clinical trial in 169 American Indians with type 2 diabetes and urine albumin/creatinine ratio <300 mg/g; 84 participants were randomly assigned to receive losartan and 85 to placebo. Primary outcome was a decline in glomerular filtration rate (GFR; iothalamate) to ≤60 mL/min or to half the baseline value in persons who entered with GFR <120 mL/min. At enrollment, GFR averaged 165 mL/min (interquartile range 49-313 mL/min). During the trial, nine persons reached the primary outcome with a hazard ratio (HR; losartan vs. placebo) of 0.50 (95% CI 0.12-1.99). Participants were then followed posttrial for up to 12 years, with treatment managed outside the study. The effect of losartan on the primary GFR outcome was then reanalyzed for the entire study period, including the clinical trial and posttrial follow-up.

RESULTS

After completion of the clinical trial, treatment with renin-angiotensin system inhibitors was equivalent in both groups. During a median of 13.5 years following randomization, 29 participants originally assigned to losartan and 35 to placebo reached the primary GFR outcome with an HR of 0.72 (95% CI 0.44-1.18).

CONCLUSIONS

Long-term risk of GFR decline was not significantly different between persons randomized to early treatment with losartan and those randomized to placebo. Accordingly, we found no evidence of an extended benefit of early losartan treatment on slowing GFR decline in persons with type 2 diabetes.

The MEST score provides earlier risk prediction in lgA nephropathy

The Oxford Classification of IgA nephropathy (IgAN) includes the following four histologic components: mesangial (M) and endocapillary (E) hypercellularity, segmental sclerosis (S) and interstitial fibrosis/tubular atrophy (T). These combine to form the MEST score and are independently associated with renal outcome. Current prediction and risk stratification in IgAN requires clinical data over 2 years of follow-up. Using modern prediction tools, we examined whether combining MEST with cross-sectional clinical data at biopsy provides earlier risk prediction in IgAN than current best methods that use 2 years of follow-up data. We used a cohort of 901 adults with IgAN from the Oxford derivation and North American validation studies and the VALIGA study followed for a median of 5.6 years to analyze the primary outcome (50% decrease in eGFR or ESRD) using Cox regression models. Covariates of clinical data at biopsy (eGFR, proteinuria, MAP) with or without MEST, and then 2-year clinical data alone (2-year average of proteinuria/MAP, eGFR at biopsy) were considered. There was significant improvement in prediction by adding MEST to clinical data at biopsy. The combination predicted the outcome as well as the 2-year clinical data alone, with comparable calibration curves. This effect did not change in subgroups treated or not with RAS blockade or immunosuppression. Thus, combining the MEST score with cross-sectional clinical data at biopsy provides earlier risk prediction in IgAN than our current best methods.

The Randomized Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) observational follow-up study: benefits of RAS blockade with olmesartan treatment are sustained after study discontinuation

Background

The Randomized Olmesartan and Diabetes Microalbuminuria Prevention (ROADMAP) study showed that 40 mg Olmesartan medoxomil (OM) versus placebo delayed microalbuminuria onset in patients with type 2 diabetes and normoalbuminuria.

Methods and Results

One thousand seven hundred and fifty‐eight ROADMAP patients (placebo arm: 877; OM arm: 881) participated in the observational follow up (OFU) with an average of 3.3 years. They received standard medical care and micro‐ and macrovascular events were documented. During observational follow‐up 62.9% and 60.1% in the former OM and placebo group, respectively, received treatment with a RAS blocking agent. During the OFU period the systolic blood pressure (SBP) increased to mean values of 135 mm Hg in both groups. Patients who had developed microalbuminuria during ROADMAP had a higher incidence of cardio‐ and cerebrovascular events (OR 1.77, CI 1.03 to 3.03, P=0.039) during the OFU period compared with patients in whom this was not the case. Diabetic retinopathy was significantly reduced in the former OM group (8 [0.9%] versus 23 [2.6%], OR: 0.34, CI 0.15 to 0.78, P=0.011) and the rate of microalbuminuria was numerically reduced. Congestive heart failure requiring hospitalization (3 [0.3%] versus 12 [1.4%], OR: 0.23, CI 0.06 to 0.85, P=0.027) was reduced and there was a trend of reduced cardio‐/cerebrovascular events (OM versus Pb: 73 [8.3%] versus 86 [9.8%] patients). Seven (0.8%) deaths (including 2 CV events) were reported in former placebo patients versus 3 (0.3%) (non‐CV events) in former OM patients.

Conclusions

Development of microalbuminuria is a valid marker for future CV events. RAS blockade with Olmesartan might cause sustained reduction (legacy effect) of micro‐ and macrovascular events.