Fanconi-Bickel syndrome complicated by nephrocalcinosis and GFR decline.

Fanconi-Bickel syndrome (FBS) is a rare genetic disorder of carbohydrate metabolism due to pathogenic variants in SLC2A2, a gene encoding glucose transporter 2 (GLUT2), which leads to accumulation of glycogen in the kidney and liver. While consequential complex proximal tubular dysfunction is well acknowledged in the literature, long-term trajectories of kidney function in patients with FBS have not been well characterized, and kidney biopsy is performed infrequently. Here, we report on a patient with FBS followed from infancy through young adulthood who presented early on with hypercalciuria, phosphaturia, and hypophosphatemia, complicated by chronic kidney disease development during childhood. Kidney biopsy, in addition to a widespread glycogen accumulation in proximal tubular epithelial cells, demonstrated medullary nephrocalcinosis. Screening for nephrocalcinosis may be warranted in pediatric patients with FBS, along with close surveillance of their kidney function.

RNA-sequencing of Human Kidney Allografts and Delineation of T-Cell Genes, Gene Sets, and Pathways Associated With Acute T Cell-mediated Rejection.

BACKGROUND: Delineation of T-cell genes, gene sets, pathways, and T-cell subtypes associated with acute T cell-mediated rejection (TCMR) may improve its management. METHODS: We performed bulk RNA-sequencing of 34 kidney allograft biopsies (16 Banff TCMR and 18 no rejection [NR] biopsies) from 34 adult recipients of human kidneys. Computational analysis was performed to determine the differential intragraft expression of T-cell genes at the level of single-gene, gene set, and pathways. RESULTS: T-cell signaling pathway gene sets for plenary T-cell activation were overrepresented in TCMR biopsies compared with NR biopsies. Heightened expression of T-cell signaling genes was validated using external TCMR biopsies. Pro- and anti-inflammatory immune gene sets were enriched, and metabolism gene sets were depleted in TCMR biopsies compared with NR biopsies. Gene signatures of regulatory T cells, Th1 cells, Th2 cells, Th17 cells, T follicular helper cells, CD4 tissue-resident memory T cells, and CD8 tissue-resident memory T cells were enriched in TCMR biopsies compared with NR biopsies. T-cell exhaustion and anergy were also molecular attributes of TCMR. Gene sets associated with antigen processing and presentation, and leukocyte transendothelial migration were overexpressed in TCMR biopsies compared with NR biopsies. Cellular deconvolution of graft infiltrating cells by gene expression patterns identified CD8 T cell to be the most abundant T-cell subtype infiltrating the allograft during TCMR. CONCLUSIONS: Our delineation of intragraft T-cell gene expression patterns, in addition to yielding new biological insights, may help prioritize T-cell genes and T-cell subtypes for therapeutic targeting.

Banff 2022 pancreas transplantation multidisciplinary report: Refinement of guidelines for T cell-mediated rejection, antibody-mediated rejection and islet pathology. Assessment of duodenal cuff biopsies and noninvasive diagnostic methods.

The Banff pancreas working schema for diagnosis and grading of rejection is widely used for treatment guidance and risk stratification in centers that perform pancreas allograft biopsies. Since the last update, various studies have provided additional insight regarding the application of the schema and enhanced our understanding of additional clinicopathologic entities. This update aims to clarify terminology and lesion description for T cell-mediated and antibody-mediated allograft rejections, in both active and chronic forms. In addition, morphologic and immunohistochemical tools are described to help distinguish rejection from nonrejection pathologies. For the first time, a clinicopathologic approach to islet pathology in the early and late posttransplant periods is discussed. This update also includes a discussion and recommendations on the utilization of endoscopic duodenal donor cuff biopsies as surrogates for pancreas biopsies in various clinical settings. Finally, an analysis and recommendations on the use of donor-derived cell-free DNA for monitoring pancreas graft recipients are provided. This multidisciplinary effort assesses the current role of pancreas allograft biopsies and offers practical guidelines that can be helpful to pancreas transplant practitioners as well as experienced pathologists and pathologists in training.

Transcriptomic signatures of chronic active antibody-mediated rejection deciphered by RNA sequencing of human kidney allografts.

Natural killer (NK) cells mediate spontaneous cell-mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity. This dual functionality could enable their participation in chronic active antibody-mediated rejection (CA-ABMR). Earlier microarray profiling studies have not subcategorized antibody-mediated rejection into CA-ABMR and active-ABMR, and the gene expression pattern of CA-ABMR has not been compared with that of T cell-mediated rejection (TCMR). To fill these gaps, we RNA sequenced human kidney allograft biopsies categorized as CA-ABMR, active-ABMR, TCMR, or No Rejection (NR). Among the 15,910 genes identified in the biopsies, 60, 114, and 231 genes were uniquely overexpressed in CA-ABMR, TCMR, and active-ABMR, respectively; compared to NR, 50 genes were shared between CA-ABMR and active-ABMR, and 164 genes between CA-ABMR and TCMR. The overexpressed genes were annotated to NK cells and T cells in CA-ABMR and TCMR, and to neutrophils and monocytes in active-ABMR. The NK cell cytotoxicity and allograft rejection pathways were enriched in CA-ABMR. Genes encoding perforin, granzymes, and death receptor were overexpressed in CA-ABMR versus active-ABMR but not compared to TCMR. NK cell cytotoxicity pathway gene set variation analysis score was higher in CA-ABMR compared to active-ABMR but not in TCMR. Principal component analysis of the deconvolved immune cellular transcriptomes separated CA-ABMR and TCMR from active-ABMR and NR. Immunohistochemistry of kidney allograft biopsies validated a higher proportion of CD56+ NK cells in CA-ABMR than in active-ABMR. Thus, CA-ABMR was exemplified by the overexpression of the NK cell cytotoxicity pathway gene set and, surprisingly, molecularly more like TCMR than active-ABMR.

Efforts to Better Characterize "Antiphospholipid Antibody Nephropathy" for the 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria: Renal Pathology Subcommittee Report.

OBJECTIVE: Antiphospholipid antibody (aPL) nephropathy (-N) can be challenging to recognize due to a lack of established classification or diagnostic criteria. As part of efforts to develop new antiphospholipid syndrome (APS) classification criteria (CC), the APS CC Renal Pathology Subcommittee aimed to better characterize the entity of aPL-N. METHODS: We used a 4-pronged approach that included (1) administering Delphi surveys to worldwide APS physicians to generate aPL-N terminology; (2) conducting a literature review to demonstrate the association of nephropathy with aPL and identify published aPL-N histopathological terminology and descriptions; (3) evaluating aPL-N terminology used in renal biopsy reports from an international patient registry; and (4) evaluating proposed kidney pathologic features for aPL-N by assessment of international Renal Pathology Society (RPS) members. RESULTS: After completing our metaanalysis demonstrating an association between nephropathy and aPL, we used Delphi surveys, a literature review, and international renal biopsy reports to develop a preliminary definition of aPL-N. The preliminary definition included include specific terms associated with acute (ie, thrombotic microangiopathy in glomeruli or arterioles/arteries) and chronic (ie, organized arterial or arteriolar microthrombi with or without recanalization, organized glomerular thrombi, fibrous and fibrocellular [arterial or arteriolar] occlusions, focal cortical atrophy with or without thyroidization, and fibrous intimal hyperplasia) lesions. Most RPS survey respondents agreed with this terminology and the importance of knowing aPL results for histopathological diagnosis. CONCLUSION: Our results support the inclusion of aPL-N in the 2023 American College of Rheumatology/European Alliance of Associations for Rheumatology APS CC, and provide the most widely accepted terminology to date for both acute and chronic pathologic lesions of aPL-N.

Clinical-Pathological Characteristics of Renal Injuries Identify Different Clusters in Patients With Antiphospholipid Antibodies.

Introduction: Significant heterogeneity still exists in the nomenclature of renal involvement in antiphospholipid syndrome (APS). Methods: We applied a hierarchical cluster analysis to determine subgroups of patients according to clinical, laboratory, and renal histology characteristics in a cohort of subjects with confirmed antiphospholipid antibodies (aPL) positivity and biopsy proven aPL-related renal injuries. Kidney outcomes were then assessed at 12 months. Results: A total of 123 aPL-positive patients were included in the study (101 [82%] female, 109 [88.6%] with systemic lupus erythematosus [SLE], 14 (11.4%) with primary APS [PAPS]). Three clusters were identified. Twenty-three patients (18.7%) were included in the first cluster (cluster 1), characterized by a higher prevalence of glomerular capillary and arteriolar thrombi and fragmented red blood cells in the subendothelial space. Cluster 2 included 33 patients (26.8%) and showed a higher prevalence of fibromyointimal proliferative lesions as seen in hyperplastic vasculopathy. Cluster 3 was the largest (67 patients, mainly with SLE) and was characterized by higher prevalence of subendothelial edema, of both glomerular capillaries and arterioles. Conclusion: Three different clusters of patients with aPL and renal injuries emerged from our study as follows: the first, with the worst renal prognosis, was associated with features of thrombotic microangiopathy (TMA), thrombosis, triple aPL positivity and higher adjusted Global APS Score (aGAPSS) values; the second, characterized by hyperplastic vasculopathy with an intermediate prognosis, was seen more frequently in patients with cerebrovascular manifestations; and the third, more benign in terms of outcomes and with no overt association with thrombotic features, was characterized by endothelial swelling in concomitant lupus nephritis (LN).

The contribution of amyloid deposition in the aortic valve to calcification and aortic stenosis.

Calcific aortic valve disease (CAVD) and stenosis have a complex pathogenesis, and no therapies are available that can halt or slow their progression. Several studies have shown the presence of apolipoprotein-related amyloid deposits in close proximity to calcified areas in diseased aortic valves. In this Perspective, we explore a possible relationship between amyloid deposits, calcification and the development of aortic valve stenosis. These amyloid deposits might contribute to the amplification of the inflammatory cycle in the aortic valve, including extracellular matrix remodelling and myofibroblast and osteoblast-like cell proliferation. Further investigation in this area is needed to characterize the amyloid deposits associated with CAVD, which could allow the use of antisense oligonucleotides and/or isotype gene therapies for the prevention and/or treatment of CAVD.

Elevated soluble urokinase plasminogen activator receptor is associated with renal dysfunction in a Chlorocebus atheiops COVID-19 model.

Increases of soluble urokinase plasminogen activator receptor (suPAR) were measured in both urine and plasma of a Chlorocebus aethiops (African green monkey; AGM) mucosal infected with SARS-CoV-2. The data indicate that elevated suPAR may be associated with renal dysfunction and pathology in the context of COVID-19.

Urinary cell mRNA profiling of kidney allograft recipients: Development of a portable protocol for noninvasive diagnosis of T cell mediated rejection and BK virus nephropathy.

BACKGROUND: We developed urinary cell mRNA profiling for noninvasive diagnosis of acute T cell mediated rejection (TCMR) and BK virus nephropathy (BKVN), two significant post-transplant complications. Our profiling protocol for the multicenter Clinical Trial of Transplantation-04 (CTOT-04) study consisted of centrifugation of urine to prepare cell pellets, washes, addition of an RNA preservative, storage at 800C and shipment in cold containers to our Gene Expression Monitoring (GEM) Core for RNA isolation and quantification of mRNA in RT-qPCR assays. To simplify profiling, we developed a filter-based protocol (ZFBP) that eliminated the need for centrifugation, RNA preservative, storage at 800C, and shipment in cold containers for mRNA profiling. Furthermore, we trained kidney allograft recipients to perform the filtration of urine at home using the filter and post the urinary cell lysate containing the RNA at ambient temperature to our GEM Core for profiling. Here, we report our refinement of ZFBP and investigation of its diagnostic performance characteristics. METHODS: Total RNA was isolated from kidney allograft biopsy-matched urines using a filter-based protocol complemented by a silica-membrane-based cartridge for mRNA enrichment, the Weill Cornell Hybrid Protocol (WCHP). Absolute copy numbers of CD3ε mRNA, CXCL10 mRNA, and 18S rRNA, components of the CTOT-04 three-gene TCMR diagnostic signature, and urinary cell BKV VP 1 mRNA copy number were measured using RT-qPCR assays. Mann-Whitney test, Fischer exact test, and receiver operating characteristic (ROC) curve analysis were used for data analyses. RESULTS: Urinary cell three-gene TCMR diagnostic signature scores in urines processed using the WCHP discriminated kidney allograft recipients with TCMR (12 TCMR biopsies from 11 patients) from those without TCMR or BKVN (29 No TCMR/No BKVN biopsies from 29 patients). The median (25th and 75th percentiles) score of the CTOT-04 three-gene TCMR diagnostic signature was -0.448 (-1.664, 0.204) in the TCMR group and - 2.542 (-3.267, -1.365) in the No TCMR/ No BKVN group (P = 0.0005, Mann-Whitney test). ROC curve analysis discriminated the TCMR group from the No TCMR/ No BKVN group; the area under the ROC curve (AUROC) was 0.84 (95% Confidence Intervals [CI], 0.69 to 0.98) (P < 0.001), and TCMR was diagnosed with a sensitivity of 67% (95% CI, 35 to 89) at a specificity of 86% (95% CI, 67 to 95) using the CTOT-04 validated cutpoint of -1.213 (P = 0.0016, Fisher exact test). BKV VP1 mRNA copy number in urines processed using the WCHP discriminated patients with BKVN (n = 7) from patients without TCMR or BKVN (n = 29) and the AUROC was 1.0 (95% CI, 1.00 to 1.00) (P < 0.0001) and BKVN was diagnosed with a sensitivity of 86% (95% CI, 42 to 99) at a specificity of 100% (95% CI, 85 to 100) with the previously validated cutpoint of 6.5 × 108 BKV-VP1 mRNA copies per microgram of RNA (P < 0.0001, Fisher exact test). CONCLUSION: Urine processed using the WCHP predicted TCMR and BKVN in kidney allograft recipients. WCHP represents not only a significant advance toward the portability of urinary cell mRNA profiling but also improved patient management by minimizing their visits for urine collection.

Type I interferon and neutrophil transcripts in lupus nephritis renal biopsies: clinical and histopathological associations.

OBJECTIVES: To investigate the expression of type I IFN (IFN-I) and neutrophil transcripts in kidney tissue from patients with different classes of LN and their association with distinct clinical and histopathological features. METHODS: Quantitation of IFN-I, defensin-α3 and formyl peptide receptor-like 1 (FPRL-1) transcripts was performed in kidney biopsy tissue from 24 patients with various classes of LN (6 class III, 14 class IV, 4 class V) and 3 control samples. Patient demographics, glomerular filtration rate (eGFR) and histopathological characteristics, including activity and chronicity indices, were analysed. RESULTS: IFNα2 and IFNß transcripts were overexpressed in renal tissues from patients with proliferative forms of LN (III/IV) compared with patients with membranous nephritis and control kidneys. Patients with LN and impaired renal function, attested by eGFR, displayed higher relative expression of IFNα2 transcripts in renal tissues compared with those with normal renal function (23.0 ± 16.2 vs 12.0 ± 14.8, P = 0.04). Defensin-α3, but not FPRL-1, transcripts were overexpressed in LN tissues, particularly those with segmental necrotizing lesions, and were correlated with higher renal pathological activity indices (r = 0.61, P = 0.02), urinary protein levels (r = 0.44, P = 0.048) and IFNα2 expression (r = 0.50, P = 0.01). CONCLUSION: IFN-I transcripts are expressed locally in kidneys from patients with proliferative LN and are associated with impaired renal function. Elevated defensin-α3 transcripts, a neutrophil product associated with neutrophil extracellular traps, may identify a driver of local IFN-I expression. These findings provide insights into the mechanisms of proliferative LN and may inform therapeutic decisions regarding selection of IFN-I pathway inhibitors.

Monoclonal Gammopathy-Related Kidney Diseases.

Monoclonal gammopathies occur secondary to a broad range of clonal B lymphocyte or plasma cell disorders, producing either whole or truncated monoclonal immunoglobulins. The kidneys are often affected by these monoclonal proteins, and, although not mutually exclusive, can involve the glomeruli, tubules, interstitium, and vasculature. The nephrotoxic potential of these monoclonal proteins is dependent on a variety of physicochemical characteristics that are responsible for the diverse clinicopathologic manifestations, including glomerular diseases with organized deposits, glomerular diseases with granular deposits, and other lesions, such as C3 glomerulopathy and thrombotic microangiopathy with unique pathophysiologic features. The diseases that involve primarily the tubulointerstitial and vascular compartments are light chain cast nephropathy, light chain proximal tubulopathy, crystal-storing histiocytosis, and crystalglobulin-induced nephropathy with distinct acute and chronic clinicopathologic features. The diagnosis of a monoclonal gammopathy-related kidney disease is established by identification of an underlying active or more commonly, low-grade hematologic malignancy, serologic evidence of a monoclonal gammopathy when detectable, and most importantly, monoclonal protein-induced pathologic lesions seen in a kidney biopsy, confirming the association with the monoclonal protein. Establishing a diagnosis may be challenging at times, particularly in the absence of an overt hematologic malignancy, with or without monoclonal gammopathy, such as proliferative glomerulonephritis with monoclonal immunoglobulin deposits. Overall, the treatment is directed against the underlying hematologic disorder and the potential source of the monoclonal protein.

Increased risk of acute and chronic microvascular renal lesions associated with antiphospholipid antibodies in patients with systemic lupus erythematosus: A systematic review and meta-analysis.

BACKGROUND: Microvascular renal lesions have been described in patients with antiphospholipid antibodies (aPL), however their association with aPL is inconsistent among studies. Therefore, our objective was to investigate associations between microvascular renal lesions and aPL among systemic lupus erythematosus (SLE) patients. METHODS: Studies were selected if they included SLE patients with and without aPL positivity with a description of kidney biopsy identifying acute and/or chronic microvascular renal lesions as well as lupus nephritis. Data sources were Pubmed, Embase, Cochrane Library, hand search, congress abstracts, and reference lists of studies, without language restrictions. Risk estimates were independently extracted by 2 investigators. Pooled effect estimates were obtained by using the Mantel-Haenszel method (random effects). RESULTS: Of 1860 identified records obtained between 1991 and 2021, 35 published studies (10 cohorts, 7 case-control, 18 cross-sectional) met inclusion criteria, including 3035 SLE patients according to American College of Rheumatology criteria and 454 cases of microvascular renal lesions. Frequency of microvascular renal lesions in aPL-positive vs. aPL-negative SLE patients was 31.3% vs. 10.4%, respectively. The overall pooled odds ratios (OR) for microvascular renal lesions in aPL-positive vs. aPL-negative SLE patients was 3.03 (95% confidence interval [CI], 2.25-4.09). The risk of microvascular renal lesions was the highest for lupus anticoagulant (OR = 4.84 [95% CI, 2.93 to 8.02]) and IgG anticardiolipin antibodies (OR = 3.12 [95% CI,1.08-9.02]) while the association with anti-ß2-glycoprotein I antibodies (OR = 1.88 [95% CI, 0.25-14.14]) did not reach statistical significance. Furthermore, aPL were not associated with any classes of lupus nephritis. CONCLUSION: In SLE patients, aPL-positivity is associated with a significant 3- to 5-fold increased risk for specific microvascular renal lesions. This risk is mainly driven by lupus anticoagulant and IgG anticardiolipin antibodies. Our results support the inclusion of microvascular renal lesions as new criteria for definite antiphospholipid syndrome.

Detection of infiltrating fibroblasts by single-cell transcriptomics in human kidney allografts.

We tested the hypothesis that single-cell RNA-sequencing (scRNA-seq) analysis of human kidney allograft biopsies will reveal distinct cell types and states and yield insights to decipher the complex heterogeneity of alloimmune injury. We selected 3 biopsies of kidney cortex from 3 individuals for scRNA-seq and processed them fresh using an identical protocol on the 10x Chromium platform; (i) HK: native kidney biopsy from a living donor, (ii) AK1: allograft kidney with transplant glomerulopathy, tubulointerstitial fibrosis, and worsening graft function, and (iii) AK2: allograft kidney after successful treatment of active antibody-mediated rejection. We did not study T-cell-mediated rejections. We generated 7217 high-quality single cell transcriptomes. Taking advantage of the recipient-donor sex mismatches revealed by X and Y chromosome autosomal gene expression, we determined that in AK1 with fibrosis, 42 months after transplantation, more than half of the kidney allograft fibroblasts were recipient-derived and therefore likely migratory and graft infiltrative, whereas in AK2 without fibrosis, 84 months after transplantation, most fibroblasts were donor-organ-derived. Furthermore, AK1 was enriched for tubular progenitor cells overexpressing profibrotic extracellular matrix genes. AK2, eight months after successful treatment of rejection, contained plasmablast cells with high expression of immunoglobulins, endothelial cell elaboration of T cell chemoattractant cytokines, and persistent presence of cytotoxic T cells. In addition to these key findings, our analysis revealed unique cell types and states in the kidney. Altogether, single-cell transcriptomics yielded novel mechanistic insights, which could pave the way for individualizing the care of transplant recipients.

Impact of Consensus Definitions on Identification of Glomerular Lesions by Light and Electron Microscopy.

INTRODUCTION: In 2020, a working group of 13 renal pathologists published consensus definitions for 47 individual glomerular lesions found on light microscopy (LM) and 47 glomerular lesions and 9 normal structures found on electron microscopy (EM). METHODS: To test the impact of these definitions on identification of these lesions and structures, 2 surveys were circulated to all members of the Renal Pathology Society (RPS), each having 32 images (19 LM, 13 EM) and accompanying questions with 5 multiple-choice answers, one being the consensus choice of the working group. The first survey (survey 1 [S1]), answered by 297 RPS members, was sent in September 2020, before publication of the consensus definitions. The second (survey 2 [S2]), with images of the same lesions and structures (but not the same images) and the same questions and multiple choices in different order, was sent in April 2020, 5 months after the publication of the definitions. RESULTS: S2 was taken by 181 RPS members; 64% also took S1 and 61% reported having read the definitions paper (def. paper). Mean agreement with the consensus answers increased modestly between the 2 surveys (65.2% vs. 72.0%, P = 0.097); the increase was greater and significant when only respondents to S2 who read the def. paper were considered (65.2% vs. 74.8%, P = 0.026). Furthermore, in S2 agreement with consensus answers was greater among respondents who read this paper versus those who did not (66.9% vs. 74.8%, P < 0.0001). CONCLUSIONS: Publication of the consensus definitions modestly improved interobserver agreement in identification of glomerular lesions.

Immunohistological score of transcription factor 21 had a positive correlation with its urinary excretion and proteinuria in immunoglobulin A nephropathy.

Transcription factor 21 (TCF21) contributes to mammalian nephrogenesis, and especially to glomerular maturation. Our previous study suggested its influence on glomerular injury, showing that TCF21 expression in podocytes had a positive correlation with the urinary protein value and also with the urinary TCF21 concentration. We now focus on its influence on the clinical course of immunoglobulin A nephropathy (IgAN), as patients with IgAN constitute the largest population of individuals with primary chronic glomerulonephritis in the world. Twenty cases of IgAN were divided into two groups according to the immunohistological score (IHS) of glomerular TCF21 expression: group IHS1 (n=7) and group IHS2+3 (n=13). Sixteen of the 20 cases were followed up for 2 years. Group IHS2+3 had heavier urinary protein (p=0.03) and a greater urinary TCF21 level (p<0.001) compared to group IHS1 at baseline. None of the other factors including hematuria, estimated glomerular filtration rate (eGFR), or the Oxford classification showed a statistically significant difference between these two groups. At the 2-year follow-up, even though the rate of remission in urinary protein, hematuria and the eGFR decline were not statistically correlated to IHS, the IHS2+3 group had a slight tendency toward a steeper eGFR decline compared to IHS1 (p=0.31). The present study suggested that the higher IHS of TCF21 corresponded to heavier proteinuria and a higher urinary TCF21 level in IgAN. This could be the first step in determining the TCF21 value for predicting the prognosis for IgAN.

Nicotine, smoking, podocytes, and diabetic nephropathy.

Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease. Besides glycemic and blood pressure control, environmental factors such as cigarette smoking (CS) adversely affect the progression of DN. The effects of CS on DN progression have been attributed to combustion-generated molecules without consideration to the role of nicotine (NIC), responsible for the addictive properties of both CS and electronic cigarettes (ECs). Podocytes are essential to preserve the structure and function of the glomerular filtration barrier, and strong evidence indicates that early podocyte loss promotes DN progression. We performed experiments in human podocytes and in a mouse model of diabetes that develops nephropathy resembling human DN. We determined that NIC binding to podocytes in concentrations achieved with CS and ECs activated NADPH oxidase, which sets in motion a dysfunctional molecular network integrated by cyclooxygenase 2, known to induce podocyte injury; downregulation of AMP-activated protein kinase, important for maintaining cellular energy stores and antioxidation; and upregulation of CD36, which increased lipid uptake and promoted apoptosis. In diabetic mice, NIC increased proteinuria, a recognized marker of chronic kidney disease progression, accompanied by reduced glomerular podocyte synaptopodin, a crucial stabilizer of the podocyte cytoskeleton, and increased fibronectin expression. This novel study critically implicates NIC itself as a contributor to DN progression in CS and EC users.NEW & NOTEWORTHY In this study, we demonstrate that nicotine increases the production of reactive oxygen species, increases cyclooxygenase-2 expression, and upregulates Cd36 while inducing downregulation of AMP-activated protein kinase. In vivo nicotine increases proteinuria and fibronectin expression in diabetic mice. This study demonstrates that effects of nicotine on podocytes are responsible, at least in part, for the deleterious effects of smoking in the progression of chronic kidney disease, including diabetic nephropathy.