Kidney Injury Molecule 1 (KIM-1): a Multifunctional Glycoprotein and Biological Marker (Review)

Modified EBP-bFGF targeting endogenous renal extracellular matrix protects against renal ischemia-reperfusion injury in rats

Acute kidney injury (AKI) is a life-threatening disease primarily caused by renal ischemia-reperfusion (I/R) injury, which can result in renal failure. Currently, growth factor therapy is considered a promising and effective approach for AKI treatment. Basic fibroblast growth factor (bFGF), an angiogenic factor with potent activity, efficiently stimulates angiogenesis and facilitates regeneration of renal tissue. However, the unrestricted diffusion of bFGF restricts its clinical application in AKI treatment. Therefore, developing a novel sustained released system for bFGF could enhance its potential in treating AKI. In this study, we genetically engineered a multifunctional recombinant protein by fusing bFGF with a specific peptide (EBP). EBP-bFGF effectively binds to the extracellular matrix in the injured kidney, enabling slow release of bFGF in AKI. Furthermore, following orthotopic injection into I/R rats' ischemic kidneys, EBP-bFGF exhibited stable retention within the tissue. Additionally, EBP-bFGF suppressed apoptosis of renal cells, reduced renal fibrosis, and facilitated recovery of renal function. These findings suggest that EBP-bFGF delivery system represents a promising strategy for treating AKI.

Protective effects of the secondary metabolites from Quercus salicina Blume against gentamicin-induced nephrotoxicity in zebrafish (Danio rerio) model

To reveal the protective effect on the nephrotoxicity of Quercus salicina Blume(QS), a traditional medicine for the treatment of urolithiasis, the 50 % ethanol extract from the branches and leaves of QS was chemically studied by systematic solvent extraction and HPLC chromatography. Two phenolic acids and three flavonoids were identified by nuclear magnetic resonance spectroscopy, namely Ferulic acid (1), p-Hydroxycinnamic acid (2), Hesperidin (3), Formononetin (4), and Quercetin (5). At the same time, the gentamicin-induced nephrotoxicity of zebrafish was used as a model for the first time. The antioxidant activity of these derivatives with good antioxidant activity screened from free radical scavenging experiments in vitro (DPPH and ABTS) was evaluated in vivo, including protein levels (LPO, NO, GSH, and SOD), kidney injury factor (KIM-1), zebrafish kidney pathology and real-time PCR. The results showed that metabolites 1, 3, and 5 had strong antioxidant activity, and oxidative stress in renal tissue was significantly reduced; KIM-1, TNF-α, and IL-6 mRNA expression in a dose-dependent manner, which preliminarily revealed the protective effect of the secondary metabolites of QS on nephrotoxicity, and preliminarily discussed the structure-activity relationship. This study provides an experimental basis for further exploring the mechanism of QS in the kidney.

Renal Protective Effect of Umbelliferone on Acute Kidney Injury in Rats via Alteration of HO-1/Nrf2 and NF-κB Signaling Pathway

Acute kidney injury (AKI), formerly known as acute renal failure, refers to a sudden and often reversible decline in kidney function. Inflammatory reaction and oxidative stress play a crucial role in the expansion of renal disease. In this experimental study, we scrutinized the renal protective effect of umbelliferone against gentamicin induced renal injury in the rats and explore the mechanism. Wistar rats were used in this study and Gentamicin was used for the induction the AKI in the rats and rats were received the oral administration of umbelliferone. The body weight, organ weight, renal, oxidative stress, cytokines, inflammatory parameters were estimated. The mRNA expression caspase-3, Bax, Bcl-2, TNF-α, IL-1β, IL-6, IL-10, HO-1, and Nrf2 were estimated. Umbelliferone remarkably improved the body weight and altered the absolute and relative weight of hepatic and renal tissue. Umbelliferone significantly suppressed the level of BUN, Scr, magnesium, calcium, phosphorus, sodium, and potassium along with altered the level of oxidative stress parameters like CAT, SOD, GSH, LPO, and GPx. Umbelliferone altered the level of cytokines viz., TNF-α, Il-1β, IL-6, IL-10; inflammatory parameters like PGE2, COX-2, TGF-β, NF-κB, respectively. Umbelliferone significantly altered the mRNA expression of caspase-3, Bax, Bcl-2, TNF-α, IL-1β, IL-6, IL-10, HO-1, and Nrf2. The result showed the renal protective effect of umbelliferone against gentamycin induced renal disease via alteration of HO-1/Nrf2 and NF-κB Signaling Pathway.

MOF-818 Nanozyme Suppresses Calcium Oxalate Kidney Stones by Alleviating Oxidative Stress and Inflammatory Injury

There remains a lack of effective drugs to alleviate the kidney stones caused by oxidative stress and inflammatory damage. The MOF-818 nanozyme is utilized to lessen the generation of reactive oxygen species (ROS) effectively, restore the membrane potential of mitochondria, regulate the cell cycle, decrease cell death, hinder the recruitment of macrophages, and mitigate the release of inflammatory factors in macrophages. These effects are attributed to the nanozyme's ability to mimic the enzyme properties of catalase (CAT) and superoxide dismutase (SOD). It is demonstrated that this nanozyme can reduce kidney calcium oxalate crystal deposition by reducing the renal injury caused by high concentration oxalate, upregulate the expression levels of SOD and CAT in tissues, downregulate adhesion proteins and inflammatory factor IL-6 and TNF-α, and promote the polarization of macrophages from M1 to M2 phenotype in the rat model induced by ethylene glycol. Overall, MOF-818 has the potential to effectively suppress oxidative stress and inflammatory harm caused by high levels of oxalate, hence lowering the likelihood of stone formation. MOF-818 nanozyme is also expected to be used as an alternative drug for the treatment of calcium oxalate kidney stones and provide an experimental theoretical basis for the development of new nanomedicines.

The Relationship between Circulating Kidney Injury Molecule-1 and Cardiovascular Morbidity and Mortality in Hemodialysis Patients

BACKGROUND

The importance of identifying mortality biomarkers in chronic kidney disease (CKD), and especially in patients treated with hemodialysis (HD), has become evident. In addition to being a marker of tubulointerstitial injury, plasma kidney injury molecule-1 (KIM-1) has been mentioned in regard to HD patients as a risk marker for cardiovascular (CV) mortality and coronary artery calcification. The aim of this study was to assess the level of plasma KIM-1 as a marker of cardiovascular disease (CVD) and mortality in CKD5-HD patients (patients with CKD stage G5D treated with hemodialysis).

METHODS

We conducted a prospective case-control study that included 63 CKD5-HD patients (HD for 1-5 years) followed up for 48 months and a control group consisting of 52 non-dialysis patients diagnosed with CKD stages G1-G5 (ND-CKD). All patients had a CVD baseline assessment including medical history, echocardiography, and electrocardiography (ECG). Circulating plasma KIM-1 levels were determined with single-molecule counting immunoassay technology using an enzyme-linked immunosorbent assay. We obtained the following parameters: serum creatinine and urea; the inflammation markers CRP (C-reactive protein) and IL-6 (interleukin-6); and the anemia markers complete blood count, serum ferritin, and transferrin saturation (TSAT).

RESULTS

The mean plasma KIM-1 level was 403.8 ± 546.8 pg/mL, showing a statistically significant correlation with inflammation (CRP, R = 0.28, p = 0.02; IL-6, R = 0.36, p = 0.005) and with anemia (hematocrit, R = -0.5, p = -0.0316; hemoglobin (Hb), R = -0.5, p = 0.02). We found that patients with left ventricular hypertrophy (LVH) on echocardiography (59.7%) had significantly lower mean levels of plasma KIM-1 than patients from the control group (155.51 vs. 432.12 pg/mL; p = 0.026). Regarding the patients' follow-up, we assessed all-cause mortality as an endpoint. After 24 months of follow-up, we found a mortality rate of 22.23%, while after 48 months, the mortality rate was 50.73%. A plasma KIM-1 level < 82.98 pg/mL was significantly associated with decreased survival in hemodialysis patients (p < 0.001).

CONCLUSIONS

In patients treated with hemodialysis, low levels of plasma KIM-1 were associated with cardiovascular changes and an increased risk of mortality. Plasma KIM-1 levels were significantly higher in HD patients compared to ND-CKD patients.

Kidney Injury in a Murine Hemorrhagic Shock/Resuscitation Model Is Alleviated by sulforaphane's Anti-Inflammatory and Antioxidant Action

Hemorrhagic shock/resuscitation (HS/R) can lead to acute kidney injury, mainly manifested as oxidative stress and inflammatory injury in the renal tubular epithelial cells, as well as abnormal autophagy and apoptosis. Sulforaphane (SFN), an agonist of the nuclear factor-erythroid factor 2-related factor 2 (Nrf2) signaling pathway, is involved in multiple biological activities, such as anti-inflammatory, antioxidant, autophagy, and apoptosis regulation. This study investigated the effect of SFN on acute kidney injury after HS/R in mice. Hemorrhagic shock was induced in mice by controlling the arterial blood pressure at a range of 35-45 mmHg for 90 min within arterial blood withdrawal. Fluid resuscitation was carried out by reintroducing withdrawn blood and 0.9% NaCl. We found that SFN suppressed the elevation of urea nitrogen and serum creatinine levels in the blood induced by HS/R. SFN mitigated pathological alterations including swollen renal tubules and renal casts in kidney tissue of HS/R mice. Inflammation levels and oxidative stress were significantly downregulated in mouse kidney tissue after SFN administration. In addition, the kidney tissue of HS/R mice showed high levels of autophagosomes as observed by electron microscopy. However, SFN can further enhance the formation of autophagosomes in the HS/R + SFN group. SFN also increased autophagy-related proteins Beclin1 expression and suppressed P62 expression, while increasing the ratio of microtubule-associated protein 1 light chain 3 (LC3)-II and LC3-I (LC3-II/LC3-I). SFN also effectively decreased cleaved caspase-3 level and enhanced the ratio of anti-apoptotic protein B cell lymphoma 2 and Bcl2-associated X protein (Bcl2/Bax). Collectively, SFN effectively inhibited inflammation and oxidative stress, enhanced autophagy, thereby reducing HS/R-induced kidney injury and apoptosis levels in mouse kidneys.

A Tripeptide (Ser-Arg-Pro, SRP) from Sipunculus nudus L. Improves Cadmium-Induced Acute Kidney Injury by Targeting the MAPK, Inflammatory, and Apoptosis Pathways in Mice

Cadmium (Cd) is a toxic heavy metal that causes nephrosis, including acute kidney injury. To prevent and treat acute kidney injury (AKI) following Cd exposure, a tripeptide, Ser-Arg-Pro (SRP), from Sipunculus nudus L. was employed, and its potential efficacy in AKI was assessed. Oral administration of SRP significantly alleviated Cd-induced kidney damage, leading to improved renal function and the attenuation of structural abnormalities. A network pharmacology analysis revealed the potential of SRP in renal protection by targeting various pathways, including mitogen-activated protein kinase (MAPK) signaling, inflammatory response, and apoptosis pathways. Mechanistic studies indicated that SRP achieves renal protection by inhibiting the activation of MAPK pathways (phosphorylation of p38, p56, ERK, and JNK) in the oxidative stress cascade, suppressing inflammatory responses (iNOS, Arg1, Cox2, TNF-α, IL-1β, and IL-6), and restoring altered apoptosis factors (caspase-9, caspase-3, Bax, and Bcl-2). Hence, SRP has the potential to be used as a therapeutic agent for the treatment of Cd-induced nephrotoxicity.

Serum soluble LYVE1 is a promising non-invasive biomarker of renal fibrosis: a population-based retrospective cross-sectional study

Diagnosis of renal fibrosis can only be verified by kidney biopsy, but biomarkers for non-invasive evaluation remain unsatisfactory. Patients with fibrosis often have abnormalities of the lymphatic vascular system and associated immune function. We describe here a lymphatic marker as a candidate biomarker for fibrosis. After assessing and grading the fibrosis scores, testing serum soluble lymphatic vessel endothelial hyaluronan receptor1 (sLYVE1) level, and collecting clinical information, the association between sLYVE1 and renal fibrosis was analyzed. Logistic regression analysis was used to screen variables. Diagnosis models with or without sLYVE1 were built, and nomograms were plotted. Calibration curve, C-index, and DCA were performed to assess the models. A total of 298 patients were enrolled in the study, of which 199 were included in the training cohort and 99 patients in the validation cohort. Serum sLYVE1 levels markedly elevated with increasing fibrosis grade (p<0.05). ROC analysis of sLYVE1 showed an AUC of 0.791 and 0.846 with optimal cut-off value of 405.25 ng/mL and 498.55 ng/mL for the prediction of moderate-to-severe renal fibrosis (MSF) and severe renal fibrosis (SF), respectively. The diagnostic nomogram model without sLYVE1 (model 1) included traditional clinical determinants (C-index: 0.658 for MSF; 0.603 for SF). A combination of model 1 and sLYVE1 (model 2) improved predictive performance (C-index: 0.847 for MSF; 0.856 for SF). Calibration curve and DCA demonstrated a better consistency accuracy and clinical benefit of model 2 than model 1. Serum sLYVE1 may be identified as a potential biomarker of renal fibrosis. Models incorporating sLYVE1 may be beneficial for a more accurate non-invasive diagnosis of renal fibrosis.

OTUD1 promotes hypertensive kidney fibrosis and injury by deubiquitinating CDK9 in renal epithelial cells

Hypertensive renal disease (HRD) contributes to the progression of kidney dysfunction and ultimately leads to end-stage renal disease. Understanding the mechanisms underlying HRD is critical for the development of therapeutic strategies. Deubiquitinating enzymes (DUBs) have been recently highlighted in renal pathophysiology. In this study, we investigated the role of a DUB, OTU Domain-Containing Protein 1 (OTUD1), in HRD models. HRD was induced in wild-type or Otud1 knockout mice by chronic infusion of angiotensin II (Ang II, 1 μg/kg per min) through a micro-osmotic pump for 4 weeks. We found that OTUD1 expression levels were significantly elevated in the kidney tissues of Ang II-treated mice. Otud1 knockout significantly ameliorated Ang II-induced HRD, whereas OTUD1 overexpression exacerbated Ang II-induced kidney damage and fibrosis. Similar results were observed in TCMK-1 cells but not in SV40 MES-13 cells following Ang II (1 μM) treatment. In Ang II-challenged TCMK-1 cells, we demonstrated that OTUD1 bound to CDK9 and induced CDK9 deubiquitination: OTUD1 catalyzed K63 deubiquitination on CDK9 with its Cys320 playing a critical role, promoting CDK9 phosphorylation and activation to induce inflammatory responses and fibrosis in kidney epithelial cells. Administration of a CDK9 inhibitor NVP-2 significantly ameliorated Ang II-induced HRD in mice. This study demonstrates that OTUD1 mediates HRD by targeting CDK9 in kidney epithelial cells, suggesting OTUD1 is a potential target in treating this disease.

Unraveling Chronic Cardiovascular and Kidney Disorder through the Butterfly Effect

Chronic Cardiovascular and Kidney Disorder (CCKD) represents a growing challenge in healthcare, characterized by the complex interplay between heart and kidney diseases. This manuscript delves into the "butterfly effect" in CCKD, a phenomenon in which acute injuries in one organ lead to progressive dysfunction in the other. Through extensive review, we explore the pathophysiology underlying this effect, emphasizing the roles of acute kidney injury (AKI) and heart failure (HF) in exacerbating each other. We highlight emerging therapies, such as renin-angiotensin-aldosterone system (RAAS) inhibitors, SGLT2 inhibitors, and GLP1 agonists, that show promise in mitigating the progression of CCKD. Additionally, we discuss novel therapeutic targets, including Galectin-3 inhibition and IL33/ST2 pathway modulation, and their potential in altering the course of CCKD. Our comprehensive analysis underscores the importance of recognizing and treating the intertwined nature of cardiac and renal dysfunctions, paving the way for more effective management strategies for this multifaceted syndrome.

Cardiac and Renal Fibrosis, the Silent Killer in the Cardiovascular Continuum: An Up-to-Date

Cardiovascular disease (CVD) and chronic kidney disease (CKD) often coexist and have a major impact on patient prognosis. Organ fibrosis plays a significant role in the pathogenesis of cardio-renal syndrome (CRS), explaining the high incidence of heart failure and sudden cardiac death in these patients. Various mediators and mechanisms have been proposed as contributors to the alteration of fibroblasts and collagen turnover, varying from hemodynamic changes to the activation of the renin-angiotensin system, involvement of FGF 23, and Klotho protein or collagen deposition. A better understanding of all the mechanisms involved has prompted the search for alternative therapeutic targets, such as novel inhibitors of the renin-angiotensin-aldosterone system (RAAS), serelaxin, and neutralizing interleukin-11 (IL-11) antibodies. This review focuses on the molecular mechanisms of cardiac and renal fibrosis in the CKD and heart failure (HF) population and highlights the therapeutic alternatives designed to target the responsible pathways.

Disposable electrochemical immunoplatform to shed light on the role of the multifunctional glycoprotein TIM-1 in cancer cells invasion

Detecting overexpression of cancer biomarkers is an excellent tool for diagnostic/prognostic and follow-up of patients with cancer or their response to treatment. This work illustrates the relevance of interrogating the levels of T-cell immunoglobulin and mucin domain 1 (TIM-1) protein as a diagnostic/prognostic biomarker of high-prevalence breast and lung cancers by using an amperometric disposable magnetic microparticles-assisted immunoplatform. The developed method integrates the inherent advantages of carboxylic acid-functionalized magnetic beads (HOOC-MBs) as pre-concentrator support and the amperometric transduction at screen-printed carbon electrodes (SPCEs). The immunoplatform involves a sandwich-type immunoassay assembled on HOOC-MBs through the specific capture/labeling of TIM-1 using capture antibodies and horseradish peroxidase (HRP)-conjugated biotinylated detection antibodies as biorecognition elements. The magnetic immunoconjugates were confined onto the working electrode (WE) surface of the SPCEs for amperometric detection using the hydroquinone/hydrogen peroxide/HRP (HQ/H2O2/HRP) redox system. The method allows the selective detection of TIM-1 protein over the 87-7500 pg mL-1 concentration range in only 45 min, with a limit of detection of 26 pg mL-1. The developed bioplatform was successfully applied to the analysis of breast and lung cancer cell extracts, providing the first quantitative results of the target glycoprotein in these types of samples.

Adherence to guidelines for management of acute kidney injury

BACKGROUND AND AIM

Acute kidney injury (AKI) affects a significant number of patients and the prognosis for this condition remains poor. The aim of this study was to assess adherence to KDIGO clinical practice guidelines and identify areas for improvement.

METHODS

For this retrospective study, data were extracted from the medical database of the University Hospital Brandenburg, for patients who had been diagnosed with AKI from January to March 2021. Implementation rates of eight KDIGO AKI therapeutic measures were analyzed in relation to several AKI severity/risk categories.

RESULTS

Data from 200 patients were included in the study. Three specific measures were commonly implemented: hyperglycemia control (100%), volume therapy (82%), and fluid balance management (65%). Nephrotoxic medications were discontinued in 51% patients, while iodinated contrast media was used in 35% patients. Patients with an increased risk of complications, such as those requiring ICU therapy or with sepsis, received these measures more frequently.

CONCLUSIONS

While some 2012 KDIGO recommended measures were implemented for a substantial number of affected individuals, others were not. Our study highlights the need for improvement in the quality of care for patients with AKI.

Combination of Urinary Neutrophil Gelatinase-associated Lipocalin, Kidney Injury Molecular-1, and Angiotensinogen for the Early Diagnosis and Mortality Prediction of Septic Acute Kidney Injury

BACKGROUND

Acute kidney injury (AKI) is one of the most severe complications of sepsis. This study was conducted to analyze the role of urinary neutrophil gelatinase-associated lipocalin (uNGAL), urinary kidney injury molecular-1 (uKIM-1), and urinary angiotensinogen (uAGT) in the early diagnosis and mortality prediction of septic AKI.

METHODS

The prospective study enrolled 80 sepsis patients in the ICU and 100 healthy individuals and divided patients into an AKI group and a non-AKI group. uNGAL, uKIM-1, uAGT, serum creatinine/procalcitonin/C-reaction protein, and other indicators were determined, and clinical prediction scores were recorded. The sensitivity and specificity of uNGAL, uKIM-1, and uAGT in diagnosis and mortality prediction were analyzed by the receiver operator characteristic (ROC) curve and the area under the curve (AUC).

RESULTS

uNGAL, uKIM-1, and uAGT levels were higher in sepsis patients than healthy controls, higher in AKI patients than non-AKI patients, and higher in AKI-2 and AKI-3 patients than AKI-1 patients. At 0 h after admission, the combined efficacy of three indicators in septic AKI diagnosis (ROC-AUC: 0.770; sensitivity: 82.5%; specificity: 70.0%) was better than a single indicator. At 24 h, uNGAL, uKIM-1, and uAGT levels were higher in sepsis non-survivals than survivals and higher in septic AKI non-survivals than septic AKI survivals. The combined efficacy of three indicators in the prediction of sepsis/septic AKI mortality (ROC-AUC: 0.828/0.847; sensitivity: 71.4%/100.0%; specificity: 82.7%/66.7%) was better than a single indicator.

CONCLUSION

uNGAL, uKIM-1, and uAGT levels were increased in septic AKI, and their combination helped the early diagnosis and mortality prediction.

Plasma Protein Profiling of Incident Cardiovascular Diseases: A Multisample Evaluation

BACKGROUND

Proteomic profiling could potentially disclose new pathophysiological pathways for cardiovascular diseases (CVD) and improve prediction at the individual level. We therefore aimed to study the plasma protein profile associated with the incidence of different CVDs.

METHODS

Plasma levels of 245 proteins suspected to be linked to CVD or metabolism were measured in 4 Swedish prospective population-based cohorts (SIMPLER [Swedish Infrastructure for Medical Population-Based Life-Course and Environmental Research], ULSAM (Uppsala Longitudinal Study of Adult Men), EpiHealth, and POEM [Prospective Investigation of Obesity, Energy Production, and Metabolism]) comprising 11 869 individuals, free of CVD diagnoses at baseline. Our primary CVD outcome was defined by a combined end point that included either incident myocardial infarction, stroke, or heart failure.

RESULTS

Using a discovery/validation approach, 42 proteins were associated with our primary composite end point occurring in 1163 subjects. In separate meta-analyses for each of the 3 CVD outcomes, 49 proteins were related to myocardial infarction, 34 to ischemic stroke, and 109 to heart failure. Thirteen proteins were related to all 3 outcomes. Of those, urokinase plasminogen activator surface receptor, adrenomedullin, and KIM-1 (kidney injury molecule 1) were also related to several markers of subclinical CVD in Prospective Investigation of Obesity, Energy production and Metabolism, reflecting myocardial or arterial pathologies. In prediction analysis, a lasso selection of 11 proteins in ULSAM improved the discrimination of CVD by 3.3% (P<0.0001) in SIMPLER when added to traditional risk factors.

CONCLUSIONS

Protein profiling in multiple samples disclosed several new proteins to be associated with subsequent myocardial infarction, stroke, and heart failure, suggesting common pathophysiological pathways for these diseases. KIM-1, urokinase plasminogen activator surface receptor, and adrenomedullin were novel early markers of CVD. A selection of 11 proteins improved the discrimination of CVD.

Clinical significance of elevated soluble T-cell immunoglobulin and mucin domain 1 and soluble P-selectin in individuals with obstructive sleep apnea-hypopnea syndrome

OBJECTIVES

To assess the serum concentrations of soluble T-cell immunoglobulin and mucin domain 1 (sTIM-1) and soluble P-selectin (sP-selectin) in individuals who had obstructive sleep apnea-hypopnea syndrome (OSAHS).

METHODS

Between December 2020 and November 2022, 134 participants from the Sleep Monitoring Center of the Branch Hospital of Huai'an First People's Hospital, Jiangsu, China, engaged in this cross-sectional study. Participants were categorized as mild OSAHS (n=19), moderate OSAHS (n=22), severe OSAHS (n=57), and non-OSAHS (n=36) groups. Serum levels of sTIM-1, sP-selectin, and interleukin (IL)-6, as well as baseline clinical characteristics and polysomnography outcomes were assessed in each participant.

RESULTS

Compared to the non-OSAHS group, sTIM-1 and sP-selectin levels were considerably elevated in people who had moderate or severe OSAHS (all p<0.05), but there were no notable changes between those who had mild OSAHS and non-OSAHS participants (p>0.05). The sTIM-1 and sP-selectin levels showed positive associations with the apnea-hypopnea index, body mass index (BMI), and IL-6 levels (all p<0.001). While elevated sTIM-1 was independently related to OSAHS (odds ratio [OR]=1.134, p=0.001), sP-selectin was not associated with OSAHS after adjusting for BMI (OR=1.013, p=0.467).

CONCLUSION

People with moderate or severe OSAHS had higher serum sTIM-1 and sP-selectin levels, and elevated sTIM-1 is an independently related factor for OSAHS.

Association between endothelial biomarkers and lipid and glycemic levels: a cross-sectional study with diabetic patients

Background: Biomarkers can help understand the impact of achieving therapeutic goals in developing vascular diseases in diabetics. Aim: To assess the association between lipid and glycemic profiles and endothelial biomarkers in diabetics. Methods: Cross-sectional study that evaluated lipid and glycemic levels and biomarkers (VCAM-1, Sdc-1, FGF-23 and KIM-1 in diabetics. Results: Higher VCAM-1 levels were associated with higher low-density lipoprotein cholesterol and non-high-density lipoprotein (HDL) cholesterol levels (in the group with inadequate glycohemoglobin A1c [HbA1c] levels), with higher glycemic levels (in the group with inadequate HDL cholesterol levels) and with lower HDL cholesterol levels (both groups). VCAM-1 was independently associated with not achieving adequate HbA1c levels. Conclusion: In uncontrolled diabetics, VCAM-1 was independently associated with having inadequate HbA1c levels, suggesting they may already have endothelial damage.

Differences in the Circulating Proteome in Individuals with versus without Sickle Cell Trait

BACKGROUND

Sickle cell trait affects approximately 8% of Black individuals in the United States, along with many other individuals with ancestry from malaria-endemic regions worldwide. While traditionally considered a benign condition, recent evidence suggests that sickle cell trait is associated with lower eGFR and higher risk of kidney diseases, including kidney failure. The mechanisms underlying these associations remain poorly understood. We used proteomic profiling to gain insight into the pathobiology of sickle cell trait.

METHODS

We measured proteomics ( N =1285 proteins assayed by Olink Explore) using baseline plasma samples from 592 Black participants with sickle cell trait and 1:1 age-matched Black participants without sickle cell trait from the prospective Women's Health Initiative cohort. Age-adjusted linear regression was used to assess the association between protein levels and sickle cell trait.

RESULTS

In age-adjusted models, 35 proteins were significantly associated with sickle cell trait after correction for multiple testing. Several of the sickle cell trait-protein associations were replicated in Black participants from two independent cohorts (Atherosclerosis Risk in Communities study and Jackson Heart Study) assayed using an orthogonal aptamer-based proteomic platform (SomaScan). Many of the validated sickle cell trait-associated proteins are known biomarkers of kidney function or injury ( e.g. , hepatitis A virus cellular receptor 1 [HAVCR1]/kidney injury molecule-1 [KIM-1], uromodulin [UMOD], ephrins), related to red cell physiology or hemolysis (erythropoietin [EPO], heme oxygenase 1 [HMOX1], and α -hemoglobin stabilizing protein) and/or inflammation (fractalkine, C-C motif chemokine ligand 2/monocyte chemoattractant protein-1 [MCP-1], and urokinase plasminogen activator surface receptor [PLAUR]). A protein risk score constructed from the top sickle cell trait-associated biomarkers was associated with incident kidney failure among those with sickle cell trait during Women's Health Initiative follow-up (odds ratio, 1.32; 95% confidence interval, 1.10 to 1.58).

CONCLUSIONS

We identified and replicated the association of sickle cell trait with a number of plasma proteins related to hemolysis, kidney injury, and inflammation.

Kidney morphology and renal expression of aquaporins 2, 3 and 4 during cerulein - Induced chronic pancreatitis in pigs

PURPOSE

Chronic pancreatitis (CP) is associated with serious complications and reduced quality of life. Kidney failure is a frequent complication of acute pancreatitis (AP), however limited information is available regarding the impact of CP on this condition. In the kidney, 9 aquaporins (AQPs) are expressed to maintain body water homeostasis and concentrate urine. The purpose of this study was to morphologically assess and analyze the location and expression of AQP2, AQP3 and AQP4 and determine whether CP affects renal structure and expression of AQPs in collecting duct (CD) principal cells.

MATERIALS/METHODS

CP was induced in domestic pigs through intramuscular injections of cerulein (1 ​μg/kg ​bw/day for 6 days; n ​= ​5); pigs without CP (n ​= ​5) were used as a control group. Kidney samples were collected 6 weeks after the last injection and subjected to histological examination. Expression of AQPs was determined by immunohistochemistry and Western blot.

RESULTS

The kidneys of animals with CP exhibited moderate changes, including glomerular enlargement, increased collagen percentage, numerous stromal erythrorrhages and inflammatory infiltrations compared to control group. Although the total abundance of AQP2 in the CD decreased in pigs after cerulein administration, the difference was not statistically significant. Expression of AQP3 and AQP4 was limited to the basolateral membrane of the CD cells. AQP4 abundance remained relatively stable in both groups, while AQP3 expression increased nearly three-fold in pigs with CP.

CONCLUSION

This study identified morphological alterations and a statistically significant increase in the expression of renal AQP3 when pigs developed CP.

Comparative effects of hepatocyte growth factor and tacrolimus on acute liver allograft early tolerance

Allostimulated CD8+ T cells (aCD8+ T cells), as the main mediators of acute liver rejection (ARJ), are hyposensitive to apoptosis due to the inactivation of death receptor FAS-mediated pathways and fail to allow tolerance induction, eventually leading to acute graft rejection. Although tacrolimus (FK506), the most commonly used immunosuppressant (IS) in the clinic, allows tolerance induction, its use is limited because its target immune cells are unknown and it is associated with increased incidences of malignancy, infection, and nephrotoxicity, which substantially impact long-term liver transplantation (LTx) outcomes. The dark agouti (DA)-to-Lewis rat LTx model is a well-known ARJ model and was hence chosen for the present study. We show that both hepatocyte growth factor (HGF) (cHGF, containing the main form of promoting HGF production) and recombinant HGF (h-rHGF) exert immunoregulatory effects mainly on allogeneic aCD8+ T cell suppression through FAS-mediated apoptotic pathways by inhibiting cMet to FAS antagonism and Fas trimerization, leading to acute tolerance induction. We also showed that such inhibition can be abrogated by treatment with neutralizing antibodies against cMet (HGF-only receptor). In contrast, we did not observe these effects in rats treated with FK506. However, we observed that the effect of anti-rejection by FK506 was mainly on allostimulated CD4+ T cell (aCD4+ T cell) suppression and regulatory T cell (Treg) promotion, in contrast to the mechanism of HGF. In addition, the protective mechanism of HGF in FK506-mediated nephrotoxicity was addressed. Therefore, HGF as a tolerance inducer, whether used in combination with FK506 or as monotherapy, may have good clinical value. Additional roles of these T-cell subpopulations in other biological systems and studies in these fields will also be meaningful.

Validation of eGFR for Detecting Associations Between Serum Protein Biomarkers and Subsequent GFR Decline

SIGNIFICANCE STATEMENT

eGFR from creatinine, cystatin C, or both has been primarily used in search of biomarkers for GFR decline. Whether the relationships between biomarkers and eGFR decline are similar to associations with measured GFR (mGFR) decline has not been investigated. This study revealed that some biomarkers showed statistically significant different associations with eGFR decline compared with mGFR decline, particularly for eGFR from cystatin C. The findings indicate that non-GFR-related factors, such as age, sex, and body mass index, influence the relationship between biomarkers and eGFR decline. Therefore, the results of biomarker studies using eGFR, particularly eGFRcys, should be interpreted with caution and perhaps validated with mGFR.

BACKGROUND

Several serum protein biomarkers have been proposed as risk factors for GFR decline using eGFR from creatinine or cystatin C. We investigated whether eGFR can be used as a surrogate end point for measured GFR (mGFR) when searching for biomarkers associated with GFR decline.

METHODS

In the Renal Iohexol Clearance Survey, GFR was measured with plasma iohexol clearance in 1627 individuals without diabetes, kidney, or cardiovascular disease at baseline. After 11 years of follow-up, 1409 participants had one or more follow-up GFR measurements. Using logistic regression and interval-censored Cox regression, we analyzed the association between baseline levels of 12 serum protein biomarkers with the risk of accelerated GFR decline and incident CKD for both mGFR and eGFR.

RESULTS

Several biomarkers exhibited different associations with eGFR decline compared with their association with mGFR decline. More biomarkers showed different associations with eGFRcys decline than with eGFRcre decline. Most of the different associations of eGFR decline versus mGFR decline remained statistically significant after adjustment for age, sex, and body mass index, but several were attenuated and not significant after adjusting for the corresponding baseline mGFR or eGFR.

CONCLUSIONS

In studies of some serum protein biomarkers, eGFR decline may not be an appropriate surrogate outcome for mGFR decline. Although the differences from mGFR decline are attenuated by adjustment for confounding factors in most cases, some persist. Therefore, proposed biomarkers from studies using eGFR should preferably be validated with mGFR.

A renal YY1-KIM1-DR5 axis regulates the progression of acute kidney injury

Acute kidney injury (AKI) exhibits high morbidity and mortality. Kidney injury molecule-1 (KIM1) is dramatically upregulated in renal tubules upon injury, and acts as a biomarker for various renal diseases. However, the exact role and underlying mechanism of KIM1 in the progression of AKI remain elusive. Herein, we report that renal tubular specific knockout of Kim1 attenuates cisplatin- or ischemia/reperfusion-induced AKI in male mice. Mechanistically, transcription factor Yin Yang 1 (YY1), which is downregulated upon AKI, binds to the promoter of KIM1 and represses its expression. Injury-induced KIM1 binds to the ECD domain of death receptor 5 (DR5), which activates DR5 and the following caspase cascade by promoting its multimerization, thus induces renal cell apoptosis and exacerbates AKI. Blocking the KIM1-DR5 interaction with rationally designed peptides exhibit reno-protective effects against AKI. Here, we reveal a YY1-KIM1-DR5 axis in the progression of AKI, which warrants future exploration as therapeutic targets.

Biomarkers Associated With Severe COVID-19 Among Populations With High Cardiometabolic Risk: A 2-Sample Mendelian Randomization Study

Importance

Cardiometabolic parameters are established risk factors for COVID-19 severity. The identification of causal or protective biomarkers for COVID-19 severity may facilitate the development of novel therapies.

Objective

To identify protein biomarkers that promote or reduce COVID-19 severity and that mediate the association of cardiometabolic risk factors with COVID-19 severity.

Design, Setting, and Participants

This genetic association study using 2-sample mendelian randomization (MR) was conducted in 2022 to investigate associations among cardiometabolic risk factors, circulating biomarkers, and COVID-19 hospitalization. Inputs for MR included genetic and proteomic data from 4147 participants with dysglycemia and cardiovascular risk factors collected through the Outcome Reduction With Initial Glargine Intervention (ORIGIN) trial. Genome-wide association study summary statistics were obtained from (1) 3 additional independent plasma proteome studies, (2) genetic consortia for selected cardiometabolic risk factors (including body mass index [BMI], type 2 diabetes, type 1 diabetes, and systolic blood pressure; all n >10 000), and (3) the COVID-19 Host Genetics Initiative (n = 5773 hospitalized and 15 497 nonhospitalized case participants with COVID-19). Data analysis was performed in July 2022.

Exposures

Genetically determined concentrations of 235 circulating proteins assayed with a multiplex biomarker panel from the ORIGIN trial for the initial analysis.

Main Outcomes and Measures

Hospitalization status of individuals from the COVID-19 Host Genetics Initiative with a positive COVID-19 test result.

Results

Among 235 biomarkers tested in samples totaling 22 101 individuals, MR analysis showed that higher kidney injury molecule-1 (KIM-1) levels reduced the likelihood of COVID-19 hospitalization (odds ratio [OR] per SD increase in KIM-1 levels, 0.86 [95% CI, 0.79-0.93]). A meta-analysis validated the protective association with no observed directional pleiotropy (OR per SD increase in KIM-1 levels, 0.91 [95% CI, 0.88-0.95]). Of the cardiometabolic risk factors studied, only BMI was associated with KIM-1 levels (0.17 SD increase in biomarker level per 1 kg/m2 [95% CI, 0.08-0.26]) and COVID-19 hospitalization (OR per 1-SD biomarker level, 1.33 [95% CI, 1.18-1.50]). Multivariable MR analysis also revealed that KIM-1 partially mitigated the association of BMI with COVID-19 hospitalization, reducing it by 10 percentage points (OR adjusted for KIM-1 level per 1 kg/m2, 1.23 [95% CI, 1.06-1.43]).

Conclusions and Relevance

In this genetic association study, KIM-1 was identified as a potential mitigator of COVID-19 severity, possibly attenuating the increased risk of COVID-19 hospitalization among individuals with high BMI. Further studies are required to better understand the underlying biological mechanisms.

Contemporary laboratory assessment of acute cardiorenal syndrome for early diagnosis: A call for action

Acute cardiorenal syndrome (CRS), categorized as CRS type 1 and 3, is defined by the interplay of acute kidney injury or dysfunction and acute cardiac disease. For optimized diagnosis and management of CRS, strategies targeting multi-organ dysfunction must be adopted. Early diagnosis of acute CRS is important to enable timely initiation of appropriate treatment to prevent serious morbidity and mortality; however, traditional biomarkers are suboptimal. Over the past 2 decades, numerous biomarkers have been investigated for a better and more rapid diagnosis of CRS. Yet, the uptake of these contemporary biomarkers has been slow, possibly owing to the use of imperfect gold-standard reference tests. We believe that there is now scope for use of contemporary laboratory test panels to improve the diagnosis of acute CRS. In this review, we briefly discuss a proposed set of biomarkers for the diagnosis of type 1 and type 3 CRS.

Current and Novel Biomarkers of Progression Risk in Children with Chronic Kidney Disease

BACKGROUND

Due to the complexity of chronic kidney disease (CKD) pathophysiology, biomarkers representing different mechanistic pathways have been targeted for the study and development of novel biomarkers. The discovery of clinically useful CKD biomarkers would allow for the identification of those children at the highest risk of kidney function decline for timely interventions and enrollment in clinical trials.

SUMMARY

Glomerular filtration rate and proteinuria are traditional biomarkers to classify and prognosticate CKD progression in clinical practice but have several limitations. Over the recent decades, novel biomarkers have been identified from blood or urine with metabolomic screening studies, proteomic screening studies, and an improved knowledge of CKD pathophysiology. This review highlights promising biomarkers associated with the progression of CKD that could potentially serve as future prognostic markers in children with CKD.

KEY MESSAGES

Further studies are needed in children with CKD to validate putative biomarkers, particularly candidate proteins and metabolites, for improving clinical management.

Acute Kidney Injury in Hospitalized Patients with COVID-19: Risk Factors and Serum Biomarkers

BACKGROUND

AKI is one of the COVID-19 complications with high prognostic significance. In our research, we studied the prognostic role of several biomarkers that could help us understand AKI pathogenesis in patients with COVID-19.

METHODS

We evaluated the medical data of 500 patients hospitalized with COVID-19 in Tareev Clinic from 5 October 2020 to 1 March 2022. The diagnosis of COVID-19 was confirmed with positive RNA PCR in nasopharyngeal swabs and/or typical radiological findings on CT scans. Kidney function was assessed in accordance with KDIGO criteria. In the selected 89 patients, we evaluated serum levels of angiopoetin-1, KIM-1, MAC, and neutrophil elastase 2 and their prognostic significance.

RESULTS

The incidence of AKI in our study was 38%. The main risk factors for kidney injury were male sex, cardiovascular diseases, and chronic kidney disease. High serum angiopoetin-1 levels and a decrease in blood lymphocyte count and fibrinogen level also increased the risk of AKI.

CONCLUSIONS

AKI is an independent risk factor for death in patients with COVID-19. We propose the prognostic model of AKI development, which includes the combination of serum levels of angiopoetin-1 and KIM-1 on admission. Our model can help to prevent AKI development in patients with coronavirus disease.

Plant or Animal-Based or PLADO Diets: Which Should Chronic Kidney Disease Patients Choose?

Nutrition therapy is the cornerstone treatment for chronic kidney disease (CKD). Although much attention has been given to dietary protein intake in CKD patients, many findings now demonstrate that the type of dietary protein intake may be more critical for CKD patients. In protein bioavailability and malnutrition prevention, many physicians recommend that CKD patients adhere to a low protein diet and restrict their plant foods, such as vegetables, fruits, and soybeans. However, nephrologists should not ignore the potential benefits of plant foods for CKD patients. It is not advisable to restrict the intake of plant foods in the later stage of CKD simply to prevent the development of hyperkalemia and malnutrition. This article highlights the benefits and possible problems of a plant-dominant low protein diet (PLADO) diet, defined as an LPD with dietary protein intake of 0.6-0.8 g/kg/day with at least 50% plant-based source for CKD patients. We hope to provide new opinions for clinical work and CKD patients.

Soluble TIM-3 as a biomarker of progression and therapeutic response in cancers and other of human diseases

Immune checkpoints inhibition is a privileged approach to combat cancers and other human diseases. The TIM-3 (T cell immunoglobulin and mucin-domain containing-3) inhibitory checkpoint expressed on different types of immune cells is actively investigated as an anticancer target, with a dozen of monoclonal antibodies in (pre)clinical development. A soluble form sTIM-3 can be found in the plasma of patients with cancer and other diseases. This active circulating protein originates from the proteolytic cleavage by two ADAM metalloproteases of the membrane receptor shared by tumor and non-tumor cells, and extracellular vesicles. In most cancers but not all, overexpression of mTIM-3 at the cell surface leads to high level of sTIM-3. Similarly, elevated levels of sTIM-3 have been reported in chronic autoimmune diseases, inflammatory gastro-intestinal diseases, certain viral and parasitic diseases, but also in cases of organ transplantation and in pregnancy-related pathologies. We have analyzed the origin of sTIM-3, its methods of dosage in blood or plasma, its presence in multiple diseases and its potential role as a biomarker to follow disease progression and/or the treatment response. In contrast to sPD-L1 generated by different classes of proteases and by alternative splicing, sTIM-3 is uniquely produced upon ADAM-dependent shedding, providing a more homogenous molecular entity and a possibly more reliable molecular marker. However, the biological functionality of sTIM-3 remains insufficiently characterized. The review shed light on pathologies associated with an altered expression of sTIM-3 in human plasma and the possibility to use sTIM-3 as a diagnostic or therapeutic marker.

Liquid biopsy at the frontier in renal cell carcinoma: recent analysis of techniques and clinical application

Renal cell carcinoma (RCC) is a major pathological type of kidney cancer and is one of the most common malignancies worldwide. The unremarkable symptoms of early stages, proneness to postoperative metastasis or recurrence, and low sensitivity to radiotherapy and chemotherapy pose a challenge for the diagnosis and treatment of RCC. Liquid biopsy is an emerging test that measures patient biomarkers, including circulating tumor cells, cell-free DNA/cell-free tumor DNA, cell-free RNA, exosomes, and tumor-derived metabolites and proteins. Owing to its non-invasiveness, liquid biopsy enables continuous and real-time collection of patient information for diagnosis, prognostic assessment, treatment monitoring, and response evaluation. Therefore, the selection of appropriate biomarkers for liquid biopsy is crucial for identifying high-risk patients, developing personalized therapeutic plans, and practicing precision medicine. In recent years, owing to the rapid development and iteration of extraction and analysis technologies, liquid biopsy has emerged as a low cost, high efficiency, and high accuracy clinical detection method. Here, we comprehensively review liquid biopsy components and their clinical applications over the past 5 years. Additionally, we discuss its limitations and predict its future prospects.

Neonatal AKI: An update

Neonatal acute kidney injury (AKI) is a common complication, especially in the neonatal intensive care unit, that is associated with long term consequences and poor outcomes. Early detection and treatment is critical. Currently, neonatal AKI is defined with urinary markers and serum creatinine, with limitations on early detection and individual treatment. There have been numerous biomarkers and risk factor scores that have been studied for their ability to predict neonatal AKI. To move towards personalized medicine, neonatal AKI must be categorized into phenotypes and subphenotypes that fully encapsulate the diverse causes and specific treatments. This review aims to advance our understanding of neonatal AKI detection through the use of biomarkers, subphenotypes, and phenotypes to move towards personalized treatment strategies.

Long-Term Complications of Radioligand Therapy with Lutetium-177 and Yttrium-90 in Patients with Neuroendocrine Neoplasms

BACKGROUND

Neuroendocrine neoplasms are a group of tumors deriving from neural crest. They can be located in every tissue, but most commonly in gastrointestinal tract. Targeted therapy with use of radionuclides is an available and acceptable way of treatment, but its long-term safety is still to be determined, especially with sensitive methods.

METHODS

Study was performed on a group of 42 patients. They underwent full cycle (4 courses; 8-12 weekly intervals) of radioligand therapy with [¹⁷⁷Lu]Lu-DOTATATE alone or tandem therapy with [¹⁷⁷Lu]Lu-DOTATATE+[⁹⁰Y]Y-DOTATATE. Late and long-term marrow and renal complications were assessed. Analysis focused on comparing data before first, fourth, and one year after the last course of RLT.

RESULTS

Study showed decreasing of all blood parameters in long-term observation, especially in lymphocytes line. Type of radioisotope, other diseases, primary tumor location, BMI, gender or age did not affect results. The only factor that had influence on hemoglobin and erythrocytes was decreased renal filtration. In long-term observation almost 10% decrease of renal filtration was observed. Type of isotope, gender, age, BMI did not affect these results. Moreover, reduction of urine IL-18, KIM-1, and albumin concentration has been observed.

CONCLUSIONS

Though low-grade complications of radioligand therapy are possible, it stay a safe method of NEN treatment where benefits outweigh the risk.

Serum Biomarkers of Renal Fibrosis: A Systematic Review

Chronic kidney disease (CKD) is a widely diffuse pathological condition which deeply impacts upon an affected patient's quality of life and its worldwide rate is predicted to further rise. The main biological mechanism underlying CKD is renal fibrosis, a non-reversible process representing, for the affected system, a point of no return of tissue damage and dysfunction, deeply reducing the possible therapeutic strategies at the disposal of physicians. The best tool clinicians can use to address the extent of renal fibrosis at any level (glomeruli, tubule-interstitium, vasculature) is kidney biopsy that, despite its overall safety, remains an invasive procedure showing some shortcomings. Thus, the identification of novel non-invasive renal fibrosis biomarkers would be of fundamental importance. Here, when systematically reviewing the available evidence on serological biomarkers associated with renal fibrosis evaluated in patients suffering from CKD in the last five years, we found that despite the presence of several promising biomarkers, the level of observed evidence is still very scattered. Probably, the use of multiple measures capable of addressing different aspects involved in this condition would be the most suitable way to capture the high complexity characterizing the renal fibrotic process, having consequently a great impact on clinical practice by maximizing prevention, diagnosis, and management.

Effect of Telmisartan and Quercetin in 5 Fluorouracil-Induced Renal Toxicity in Rats

PURPOSE

The present study was designed to evaluate the possible synergistic effects of telmisartan and quercetin in 5 fluorouracil (5-FU) induced nephrotoxicity in rats.

METHODOLOGY

Forty male rats were randomly divided into five groups: The negative control group, the positive control group that received 5-FU, the telmisartan group, receiving 10 mg/kg, the quercetin group, receiving 80 mg/kg, and the combination of telmisartan and quercetin group. All the treatments were given orally for 14 days. A single intraperitoneal injection of 5-FU (150 mg/kg) on day 13 of the experiment was given except for the negative control group. On the 15th day after scarification, approximately 5 mL of blood was collected and used for measurement of CBC, urea, creatinine, and uric acid. The kidneys were used for histopathological examination and for the measurement of kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), Cystatin C (Cys-C), and total antioxidant capacity (TAOC).

RESULTS

The combination therapy significantly attenuated the levels of tissue KIM-1, NGAL, Cys-C, and serum uric acid as well as blood inflammatory markers, Neutrophil/Lymphocyte (NLR), Monocyte/Lymphocyte (MLR), and Platelets/Lymphocyte ratios (PLR), and restored the TAOC. The histopathological findings greatly support the biochemical tests.

CONCLUSION

The results strongly suggest the renoprotective effects of telmisartan and quercetin in combination against the nephrotoxic effect of 5-FU through decreasing the levels of KIM-1, NGAL, and cys-C, and the novel inflammatory markers of kidney injury like NLP, MLR, and PLR, as well as decreasing uric acid and restoring the TAOC. The proposed mechanism could be the additive inhibitory effect on RAS provided by both telmisartan and quercetin.

Research progress of risk factors and early diagnostic biomarkers of gout-induced renal injury

Gout renal injury has an insidious onset, no obvious symptoms, and laboratory abnormalities in the early stages of the disease. The injury is not easily detected, and in many cases, the patients have entered the renal failure stage at the time of diagnosis. Therefore, the detection of gout renal injury–related risk factors and early diagnostic biomarkers of gout renal injury is essential for the prevention and early diagnosis of the disease. This article reviews the research progress in risk factors and early diagnostic biomarkers of gout renal injury.

Urinary KIM-1 Correlates with the Subclinical Sequelae of Tubular Damage Persisting after the Apparent Functional Recovery from Intrinsic Acute Kidney Injury

Acute kidney injury (AKI) poses an increased risk factor for new AKI episodes, progression to chronic kidney disease, and death. A worsened evolution has been linked to an incomplete renal repair beyond the apparent functional recovery based on plasma creatinine (pCr) normalization. However, structural sequelae pass largely unnoticed due to the absence of specific diagnostic tools. The urinary kidney injury molecule 1 (KIM-1) participates in renal tissue damage and repair and is proposed as a biomarker of early and subclinical AKI. Thus, we study in this paper the evolution of KIM-1 urinary excretion alongside renal tissue sequelae after an intrinsic AKI episode induced by cisplatin in Wistar rats. Creatinine clearance, pCr, proteinuria and the fractional excretion of Na+ and glucose were used to monitor renal function. Renal tissue damage was blindly scored in kidney specimens stained with hematoxylin-eosin and periodic acid-Schiff. KIM-1 urinary excretion and renal mRNA expression were also assessed. Finally, we analyzed urinary KIM-1 in patients apparently recovered from AKI. Our results show that, after the normalization of the standard markers of glomerular filtration and tubular function, the extent of persistent histological findings of tissue repair correlates with the renal expression and urinary level of KIM-1 in rats. In addition, KIM-1 is also elevated in the urine of a significant fraction of patients apparently recovered from an AKI. Besides its potential utility in the early and subclinical diagnosis of renal damage, this study suggests a new application of urinary KIM-1 in the non-invasive follow-up of renal repair after AKI.

A Mixture of Pure, Isolated Polyphenols Worsens the Insulin Resistance and Induces Kidney and Liver Fibrosis Markers in Diet-Induced Obese Mice

Obesity is a worldwide epidemic with severe metabolic consequences. Polyphenols are secondary metabolites in plants and the most abundant dietary antioxidants, which possess a wide range of health effects. The most relevant food sources are fruit and vegetables, red wine, black and green tea, coffee, virgin olive oil, and chocolate, as well as nuts, seeds, herbs, and spices. The aim of this work was to evaluate the ability of a pure, isolated polyphenol supplementation to counteract the pernicious metabolic effects of a high-fat diet (HFD). Our results indicated that the administration of pure, isolated polyphenols under HFD conditions for 26 weeks worsened the glucose metabolism in diet-induced obese mice. The data showed that the main target organ for these undesirable effects were the kidneys, where we observed fibrotic, oxidative, and kidney-disease markers. This work led us to conclude that the administration of pure polyphenols as a food supplement would not be advisable. Instead, the ingestion of complete "whole" foods would be the best way to get the health effects of bioactive compounds such as polyphenols.