Context: Diabetic retinopathy (DR) and diabetic nephropathy (DN), are major microvascular complications of diabetes. DR is an important predictor of DN, but the relationship between the severity of DR and the pathological severity of diabetic glomerulopathy remains unclear.Objective: To investigate the relationship between severity of diabetic retinopathy (DR) and histological changes and clinical indicators of diabetic nephropathy (DN) in patients with type 2 diabetes mellitus (T2DM)Methods: Patients with T2DM (n=272) who underwent a renal biopsy were eligible. Severity of DR was classified as non-diabetic retinopathy, non-proliferative retinopathy, and proliferative retinopathy (PDR). Relationship between DN and DR and the diagnostic efficacy of DR for DN were explored.Results: DN had a higher prevalence of DR (86.4%) and DR was more severe. The sensitivity and specificity of DR in DN were 86.4% and 78.8%, while PDR was 26.4% and 98.5%, respectively. In DN patients, the severity of glomerular lesions (p=0.001) and prevalence of KW nodules (p<0.001) significantly increased with increasing severity of DR. The presence of KW nodules, lower hemoglobin levels, and younger age were independent risk factors associated with more severe DR in patients with DN.Conclusion: DR was a good predictor of DN. In DN patients, the severity of DR was associated with glomerular injury, and presence of KW nodules, lower hemoglobin levels and younger age were independent risk factors associated with more severe DR.Trial registration: ClinicalTrails.gov, NCT03865914.

Renal fibrosis-characterized by microcirculatory disturbances and endothelial-mesenchymal transition (EndMT)-is a major pathological feature of chronic kidney disease (CKD) and remains a significant therapeutic challenge. The mechanosensitive ion channel Piezo1 plays a pivotal role in endothelial mechanotransduction and has been implicated in fibrogenesis, yet specific pharmacological interventions targeting Piezo1 are lacking. We evaluated the renoprotective effects of paeoniflorin (PF), a bioactive monoterpene glycoside, in 5/6 nephrectomy-induced chronic renal failure (CRF) rats and diabetic kidney disease (DKD) db/db mice. PF-Piezo1 interactions were characterized using molecular docking, surface plasmon resonance (SPR), and functional assays. In vitro studies employing models of matrix stiffness, endothelial-fibroblast crosstalk, and HIF-1α inhibition were performed to elucidate the underlying mechanisms. PF treatment preserved renal function, reduced glomerulosclerosis, and ameliorated microvascular rarefaction in both CRF and DKD. Molecular docking and SPR analyses revealed that PF binds Piezo1 with high affinity, thereby inhibiting Yoda1-induced Ca2⁺ influx and attenuating stiffness-induced EndMT. PF restored the expression of endothelial markers including VE-cadherin and eNOS, and suppressed HIF-1α-mediated upregulation of Vimentin and TGF-β1. Moreover, co-culture experiments demonstrated that PF disrupted endothelial-derived TGF-β1 paracrine signaling, reducing fibroblast activation and extracellular matrix deposition. Notably, Piezo1 knockdown or HIF-1α inhibition recapitulated the dual effects of PF on endothelial restoration and fibrosis suppression. Our findings indicate that PF exerts renoprotective effects by targeting the Piezo1/Ca²⁺/HIF-1α axis, thereby mitigating renal fibrosis. By interrupting pathological endothelial-fibroblast communication and restoring microvascular integrity, PF represents a promising mechanotherapeutic strategy for CKD.

Diabetic kidney disease (DKD) is one of the leading causes of end-stage renal disease worldwide and significantly increases the risk of premature death due to cardiovascular diseases. Elevated urinary albumin levels are an important clinical feature of DKD. Effective control of albuminuria not only delays glomerular filtration rate decline but also markedly reduces cardiovascular disease risk and all-cause mortality. New drugs for treating DKD proteinuria, including sodium-glucose cotransporter two inhibitors, mineralocorticoid receptor antagonists, and endothelin receptor antagonists, have shown significant efficacy. Auxiliary treatment with proprietary Chinese medicine has also yielded promising results; however, it also faces a broader scope for development. The mechanisms by which these drugs treat albuminuria in patients with DKD should be described more thoroughly. The positive effects of combination therapy with two or more drugs in reducing albuminuria and protecting the kidneys warrant further investigation. Therefore, this review explores the pathophysiological mechanism of albuminuria in patients with DKD, the value of clinical diagnosis and prognosis, new progress and mechanisms of treatment, and multidrug therapy in patients who have type 2 diabetic kidney disease, providing a new perspective on the clinical diagnosis and treatment of DKD.

Diabetes mellitus is one of the most critical global health concerns, with a fast-growing prevalence. The incidence of diabetic vascular complications is also rapidly increasing, exacerbating the burden on individuals with diabetes and the consumption of public medical resources. Despite the overall improvements in the prevention, diagnosis, and treatment of diabetic microvascular complications in recent years, safe and effective alternative or adjunctive therapies are urgently needed. The mechanisms underlying diabetic vascular complications are complex, with hyperglycemia-induced oxidative stress and inflammation being the leading causes. Therefore, glycemic control, antioxidation, and anti-inflammation are considered the main targets for the treatment of diabetes and its vascular comorbidities. Vaccinium L. (Ericaceae) is a genus of plants enriched with polyphenolic compounds in their leaves and fruits. Vaccinium and its extracts have demonstrated good bioactivity in reducing blood glucose, oxidative stress, and inflammation, making them excellent candidates for the management of diabetes and diabetic vascular complications. Here, we review recent preclinical and clinical studies on the potential effect of Vaccinium on ameliorating diabetes and diabetic complications, particularly diabetic kidney disease and diabetic retinopathy.

The presence of macrophages surrounding lipotoxic tubular epithelial cells (TECs) is a hallmark of diabetic nephropathy (DN). Nevertheless, the mechanisms of communication between these cell types are not well understood. Previous studies have revealed a unique subset of macrophages that express triggering receptor expressed on myeloid cells 2 (Trem2) in kidneys of human patients and mice with DN. Here, we explored the characteristics and the function of Trem2+ macrophages in the progress of DN. RNA-sequencing of macrophages in kidneys of Trem2 knockout (KO) mice fed a high-fat diet plus streptozotocin (HFD/STZ) revealed functional enrichment of metabolic processes, cytokine production, positive regulation of extracellular signal-regulated kinase (ERK) cascades, and the regulation of phagocytosis. In vivo studies demonstrated that Trem2+ macrophages reduced lipid accumulation and mitigated ferroptosis of TECs in diabetic mice. Mechanistically, Trem2-deficient macrophages amplified the production of interleukin-1β (IL-1β) through activating the ERK signaling pathway. Furthermore, IL-1β triggered CD36 expression via the transcription factor NF-κB. Bioinformatics and functional assays showed NF-κB binds the CD36 promoter, which directly bound to the promoters of CD36 to facilitate its transcription. Inhibition of NF-κB blocked IL-1β–induced CD36 production. This mechanism is exacerbated in Trem2-deficient macrophages, which release excess IL-1β to activate NF-κB in tubular cells, promoting CD36-dependent lipid uptake and ferroptosis. Additionally, we found Trem2 plays a role in enhancing the phagocytosis and clearance of ferroptotic cells by bone marrow-derived macrophages. Altogether, our results suggest Trem2+ macrophages maintain homeostasis of the renal microenvironment and exert a protective function in DN. Article Highlights: Levels of triggering receptor expressed on myeloid cells 2 (Trem2) in macrophages are increased in human patients and in mice with diabetic nephropathy. Trem2 suppresses the extracellular signal-regulated kinase signaling pathways, thereby inhibiting IL-1β production in macrophages. Macrophage Trem2 deficiency exacerbates tubular cell lipid deposition and ferroptosis by increasing CD36 expression in an IL-1β–dependent manner

Background: Population aging is a pivotal trend observed globally, and the exposure to heavy metals can exacerbate the aging process and lead to kidney damage. However, the impact of combined heavy metal exposure on renal function among older individuals remains elusive. Our study employs machine learning techniques to delve into the effects and underlying mechanisms of mixed exposure to heavy metals on the renal function of the aging population.Methods: This study extracted comprehensive data from the National Health and Nutrition Examination Survey (NHANES) conducted between 2015 and 2020. A total of 3,175 participants aged 60 years and above, with complete information on six metals – lead, cadmium, manganese, cobalt, mercury, and selenium, along with relevant covariates, were included in the study. To assess the impact of single or mixed metal exposure on the renal function of older adult individuals, various statistical techniques were employed: multiple logistic regression, weighted quantitative sum (WQS) regression, Bayesian kernel machine regression (BKMR), and mediation effects analysis.Results: Multiple logistic regression revealed that selenium and manganese were protective factors for chronic kidney disease (CKD). Cobalt was a risk factor for CKD. High concentrations of lead, cadmium, and cobalt were risk factors for urinary albumin creatinine ratio (ACR). WQS analyses revealed that mixed metal exposure was positively correlated with estimated glomerular filtration rate (eGFR) but negatively correlated with CKD. Selenium and manganese can neutralize the effects of other metals on eGFR. Mixed metal exposure was positively correlated with ACR, with lead and cadmium having a substantial effect. Mediation analysis showed that uric acid (UA) had a mediating effect of 9.7% and −19.7% in the association between mixed metals exposure and proteinuria and CKD, respectively.Conclusion: The impact of heavy metals on renal function in the older adult differs from that of adolescents and adults. This study suggests that elevated levels of mixed metals exposure are linked to proteinuria and CKD, with UA serving as a mediating factor.