Largely on the basis of data from patients with type 1 diabetes, the natural history of diabetic renal disease has been classified as a sequence of three stages: normoalbuminuria, microalbuminuria, ...and macroalbuminuria. Progressive decline of glomerular filtration rate (GFR) was thought to parallel the onset of macroalbuminuria (overt nephropathy), whereas glomerular hyperfiltration was deemed a hallmark of early disease. However, researchers have since shown that albuminuria is a continuum and that GFR can start to decline before progression to overt nephropathy. In addition to proteinuria, other risk factors might contribute to GFR deterioration including female sex, obesity, dyslipidaemia (in particular hypertriglyceridaemia), hypertension, and glomerular hyperfiltration, at least in a subgroup of patients. This phenomenon could explain why patients with type 2 diabetes can have renal insufficiency even before the onset of overt nephropathy, and might also suggest why the heterogeneous phenotype of type 2 diabetic renal disease does not necessarily associate with typical histological lesions of diabetic renal disease, unlike in type 1 diabetic renal disease. Patients with renal insufficiency but without albuminuria are usually excluded from randomised clinical trials in overt nephropathy, thus optimum treatment for this group of patients is unknown. The wide inter-patient variability of the disease probably needs individually tailored intervention.
This study aimed to investigate obesity-related glomerulopathy (ORG) at cellular, structural, and transcriptomic levels. Thirty Wistar rats were randomized into two groups: 15 rats were fed with a ...standard diet (SD-rats), and 15 rats were fed with a high-fat diet (HFD-rats). After 10 weeks, the weight, kidney function, histological features, and transcriptomic changes were assessed. HFD-rats gained significantly more weight (55.8% vs. 29.2%; p < 0.001) and albuminuria (10,384.04 ng/mL vs. 5845.45 ng/mL; p < 0.001) compared to SD-rats. HFD-rats exhibited early stages of ORG, with predominant mesangial matrix increase and podocyte hypertrophy (PH). These lesions correlated with differentially expressed (DE) genes and miRNAs. Functional analysis showed that miR-205, which was DE in both the kidneys and urine of HFD-rats, negatively regulated the PTEN gene, promoting lipid endocytosis in podocytes. The downregulation of PTEN was proved through a higher PTEN/nephrin ratio in the SD-rats and the presence of lipid vacuoles in HFD-podocytes. This study has found a specific targetome of miRNAs and gene expression in early stages of ORG. Also, it emphasizes the potential value of miR-205 as a urinary biomarker for detecting podocyte injury in ORG, offering a tool for early diagnosis, and opening new avenues for future therapeutic research of obesity-related glomerulopathy.
Purpose
The role of non-tumour renal biopsy in predicting renal function after surgery for renal cell carcinoma (RCC) is poorly investigated. The aim of the study was to assess the impact of renal ...parenchymal histology on renal function after radical nephrectomy in a cohort of patients with RCC.
Methods
This cohort study included 171 patients with RCC submitted to radical nephrectomy between 2006 and 2018. Two biopsy samples from normal parenchyma were collected at nephrectomy and renal parenchyma damage (RPD) was scored on histologic samples according to validated methodology. The outcomes were eGFR after surgery and its reduction > 25% relative to baseline at maximum 12 months’ follow-up. Linear and logistic multivariable regression were used, adjusting for age at surgery, presence of hypertension, diabetes, clinical tumour size, time from surgery and basal eGFR.
Results
171 patients were enrolled and RPD was demonstrated in 64 (37%). Patients with RPD had more comorbidities (CCI > 2 in 25 vs. 9%,
p
< 0.001), in particular hypertension (70 vs. 53%;
p
= 0.03), diabetes with (5% vs. 0%,
p
= 0.007) or without (31 vs. 18%;
p
= 0.007) organ damage, cerebrovascular disease (19 vs. 5%;
p
= 0.006) and nephropathy (20 vs. 3%;
p
= 0.0004). At multivariable analyses, RPD was associated with lower eGFR (Est. − 5.48; 95% CI − 9.27: − 1.7;
p
= 0.005) and with clinically significant reduction of eGFR after surgery (OR 3.06; 95% CI 1.17: 8.49;
p
= 0.026).
Conclusions
Presence of RPD in non-tumour renal tissue is an independent predictor of functional impairment in patients with RCC. Such preliminary finding supports the use of parenchyma biopsy during clinical decision making.
Background
The chronic kidney disease (CKD) classification represents a simple tool to evaluate kidney disease. However, it is not based on kidney histology and this might limit the correlation ...between renal function and histological damage. The aim of this study was to examine the presence and magnitude of the discordance between CKD classification and kidney histology.
Materials and methods
We retrospectively analyzed kidney parenchyma histology in a cohort of 200 patients who underwent radical nephrectomy for a kidney mass to observe its correlation with CKD classification. Kidney tissue of the unaffected part of the removed kidney was analyzed and classified with a chronicity score as described by Sethi et al. Then, all patients were classified according to the respective CKD stage using different equations: CKD-EPI, MDRD, FAS and MCQ.
Results
Median age was 67 (57–75). Diabetes, hypertension and overweight were observed in 23%, 60% and 61%, respectively. The CKD-EPI equation stratified 30.5% (
n
= 61) of the subjects into CKD stage 1, 41.5% (
n
= 83) into CKD stage 2, 25.5% into CKD stage 3 (
n
= 51) and 2.5% into CKD stage 4–5 (
n
= 5). About 30–40% of the patients with CKD stage 3 had mild or no lesions in the histological evaluation (Chronicity Score = 0–1), whereas 7–10% of those with CKD stage 1 had moderate or severe histological lesions (Chronicity Score ≥ 3). Different patients with the same value of estimated glomerular filtration rate (eGFR) had either severe or no histological damage.
Conclusions
The variability of kidney histology observed within each CKD stage is not negligible. This may limit the reliability of the current CKD classification. More research is needed to clarify the relationship between CKD stages and kidney damage.
Graphic abstract
The pathogenesis of obesity-related-renal disease is unknown. Menopause can promote renal disease in obese women, but this interaction is unclear. In a previous study, we observed that obese male and ...female mice developed albuminuria, hyperfiltration, and glomerulomegaly, and these changes were more severe in those obese ovariectomized females. In this study, we also evaluated renal inflammation and lipotoxicity in that animal model. For six months, 43 males and 36 females C57BL6/J mice were randomized to standard diet (SD) or high fat diet (HFD). A group of female animals on SD or HFD was ovariectomized to simulate menopause. We evaluated cytokines: NF-κβ p65, IL-1β, MCP-1, TNF-α, total lipid content, lipid classes, and fatty acid profile in total lipid and individual lipid classes in renal tissue and urine. We found that obese males and females showed higher NF-kβ p-65, TNF-α and MCP-1 in renal tissue, and obese females ovariectomized had higher IL-1β and TNF-α compared with not-ovariectomized. Also, obese animals showed lower proinflammatory and higher anti-inflammatory fatty acids in kidney total lipids, while obese females ovariectomized had a more exacerbated pattern. In brief, obesity induces inflammation and an unbalanced lipidic profile in renal tissue. This pattern seems to be enhanced in obesity after menopause.
The pathogenesis of Post-Transplant Diabetes Mellitus (PTDM) is complex and multifactorial and it resembles that of Type-2 Diabetes Mellitus (T2DM). One risk factor specific to PTDM differentiates ...both entities: the use of immunosuppressive therapy. Specifically, Tacrolimus interacts with obesity and insulin resistance (IR) in accelerating the onset of PTDM. In a genotypic model of IR, the obese Zucker rats, Tacrolimus is highly diabetogenic by promoting the same changes in beta-cell already modified by IR. Nevertheless, genotypic animal models have their limitations and may not resemble the real pathophysiology of diabetes. In this study, we have evaluated the interaction between beta-cell damage and Tacrolimus in a non-genotypic animal model of obesity and metabolic syndrome.
Sprague Dawley rats were fed a high-fat enriched diet during 45 days to induce obesity and metabolic dysregulation. On top of this established obesity, the administration of Tacrolimus (1mg/kg/day) during 15 days induced severe hyperglycaemia and changes in morphological and structural characteristics of the pancreas.
Obese animals administered with Tacrolimus showed increased size of islets of Langerhans and reduced beta-cell proliferation without changes in apoptosis. There were also changes in beta-cell nuclear factors such as a decrease in nuclear expression of MafA and a nuclear overexpression of FoxO1A, PDX-1 and NeuroD1. These animals also showed increased levels of pancreatic insulin and glucagon.
This model could be evidence of the relationship between the T2DM and PTDM physiopathology and, eventually, the model may be instrumental to study the pathogenesis of T2DM.
Autosomal polycystic kidney disease (ADPKD) is the most common genetic form of kidney failure, reflecting unmet needs in management. Prescription of the only approved treatment (tolvaptan) is limited ...to persons with rapidly progressing ADPKD. Rapid progression may be diagnosed by assessing glomerular filtration rate (GFR) decline, usually estimated (eGFR) from equations based on serum creatinine (eGFRcr) or cystatin-C (eGFRcys). We have assessed the concordance between eGFR decline and identification of rapid progression (rapid eGFR loss), and measured GFR (mGFR) declines (rapid mGFR loss) using iohexol clearance in 140 adults with ADPKD with ≥3 mGFR and eGFRcr assessments, of which 97 also had eGFRcys assessments. The agreement between mGFR and eGFR decline was poor: mean concordance correlation coefficients (CCCs) between the method declines were low (0.661, range 0.628 to 0.713), and Bland and Altman limits of agreement between eGFR and mGFR declines were wide. CCC was lower for eGFRcys. From a practical point of view, creatinine-based formulas failed to detect rapid mGFR loss (-3 mL/min/y or faster) in around 37% of the cases. Moreover, formulas falsely indicated around 40% of the cases with moderate or stable decline as rapid progressors. The reliability of formulas in detecting real mGFR decline was lower in the non-rapid-progressors group with respect to that in rapid-progressor patients. The performance of eGFRcys and eGFRcr-cys equations was even worse. In conclusion, eGFR decline may misrepresent mGFR decline in ADPKD in a significant percentage of patients, potentially misclassifying them as progressors or non-progressors and impacting decisions of initiation of tolvaptan therapy.
Intrauterine Growth Restriction (IUGR) hinders the correct growth of the fetus during pregnancy due to the lack of oxygen or nutrients. The developing fetus gives priority to brain development ...(“brain sparing”), but the risk exists of neurological and cognitive deficits at short or long term. On the other hand, diets rich in fat exert pernicious effects on brain function. Using a pig model of spontaneous IUGR, we have studied the effect on the adult of a long-term high-fat diet (HFD) on the neurotransmitter profile in several brain areas, and the morphology and the proteome of the hippocampus. Our hypothesis was that animals affected by IUGR (born with low birth weight) would present a different susceptibility to an HFD when they become adults, compared with normal birth-weight animals. Our results indicate that HFD affected the serotoninergic pathway, but it did not provoke relevant changes in the morphology of the hippocampus. Finally, the proteomic analysis revealed that, in some instances, NBW and LBW individuals respond to HFD in different ways. In particular, NBW animals presented changes in oxidative phosphorylation and the extracellular matrix, whereas LBW animals presented differences in RNA splicing, anterograde and retrograde transport and the mTOR pathway.
Glomerulosclerosis and tubulointerstitial fibrosis are pathological features of chronic kidney disease. Transforming growth factor β (TGFβ) is a key player in the development of fibrosis. However, of ...the three known TGFβ isoforms, only TGFβ1 has an established role in fibrosis, and the pathophysiological relevance of TGFβ2 and TGFβ3 is unknown. Because Tgfb3 deficiency in mice results in early postnatal lethality, we analyzed the kidney phenotype of heterozygous Tgfb3-knockout mice (Tgfb3+/-) and compared it with that of matched wild-type mice. Four-month-old Tgfb3+/- mice exhibited incipient renal fibrosis with epithelial-mesenchymal transition, in addition to glomerular basement membrane thickening and podocyte foot process effacement associated with albuminuria. Also evident was insulin resistance and oxidative stress at the renal level, together with aberrant renal lipid metabolism and mitochondrial function. Omics analysis revealed toxic species, such as diacylglycerides and ceramides, and dysregulated mitochondrial metabolism in Tgfb3+/- mice. Kidneys of Tgfb3+/- mice showed morphological alterations of mitochondria and overactivation of non-canonical MAPK ERK1/2 and JNK cascades. Our study indicates that renal TGFβ3 might have antifibrotic and renoprotective properties, opposing or counteracting the activity of TGFβ1. This article has an associated First Person interview with the first author of the paper.
Hospital admissions and mortality from the Coronavirus disease 2019 (COVID-19) pandemic are spreading throughout the world, and second and third waves are thought to be likely. Risk factors for ...severe COVID-19 include diabetes, chronic kidney disease and cardiovascular disease. Currently, there is no vaccine and no approved therapy. Therapeutic approaches are aimed at preventing viral replication and spread, limiting the impact of the inflammatory overdrive (cytokine storm), preventing thromboembolic complications and replacing or supporting organ function. However, despite organ support, mortality is currently 65% for those receiving advanced respiratory support and 78% for those requiring renal replacement therapies. Thus, efforts should be made to provide adjuvant organ protection therapy. This may imply novel therapies in clinical development (e.g., the Fas ligand trap asunercept), but uptake of repurposed drugs already in clinical use may be faster. In this regard, sodium glucose co-transporter-2 (SGLT2) inhibitors were recently shown to protect the heart and kidney both within and outside of a diabetic milieu context. Further, preclinical data support a beneficial effect for the lung. We now discuss the potential benefits and risks of SGLT2 inhibitors in COVID-19 and an ongoing clinical trial testing the impact of dapagliflozin on outcomes in COVID-19 patients with respiratory failure.
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