On the occassion of world kidney day 2023; renal impacts of COVID-19

World kidney day is an international campaign focused on bringing awareness to kidney health throughout the world and reducing the incidence of renal disease and its related medical complications. This mini-review sought to take a short look on the renal impact of SARS-CoV-2, with a particular focus on post-COVID-19 nephropathy as a new dilemma in the era of nephrology, which can be a new concern for nephrologists that requires more attention and particular strategies.

Systemic lupus erythematosus following SARS-CoV-2 vaccination; a review of literature

From March 2020, the coronavirus disease 2019 (COVID-19) pandemic challenged public health and healthcare systems worldwide. Viral infection is one of the environmental factors that has been associated with the development, relapse, or exacerbation of systemic lupus erythematosus (SLE). SLE patients are at an increased risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because of immune system dysfunction related to their disease as well as immunosuppression medications. So far, the most effective way to reduce SARS-CoV-2 infection-induced hospitalization and death is vaccination. On the other hand, SLE patients present distinct challenges related to the safety and effectiveness of SARS-CoV-2 vaccination. We have reviewed some reports on the onset or flare of SLE post-COVID-19 vaccination. Of note, the mRNA COVID-19 vaccines are associated with increased SLE disease activity, more frequently than the other types of COVID-19 vaccines.

Strive for kidney health for everyone during COVID-19; the possible theme for the world kidney day 2021

Increasing awareness regarding CKD and self-care during COVID-19 pandemic has become the most important aspect for the nephrologists. Hence it is appropriate that the theme of the forthcoming World Kidney Day on 11 March 2021 should be "Strive for kidney health for everyone during COVID-19"

Perspectives on the relationship of renal disease and coronavirus disease 2019

Coronavirus disease 2019 (COVID-19) is now a pandemic and its death toll is rocketing up. Patients with acute kidney injury (AKI) and chronic kidney disease (CKD) are at high risk of developing COVID-19 complications and COVID-19 infection can also lead to renal dysfunction. Considering the importance of kidney function in COVID-19 patients, the present review is aimed to dig into the available evidence about kidney and COVID-19. We summarize the mechanisms underlying the renal injury in COVID-19 patients, and treatment strategies in dialysis and kidney transplant patients. We conclude, it is imperative to highlight the early monitoring of patients with AKI and carefully control kidney function during severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) infection.

A story of microalbuminuria and diabetic nephropathy

CONTEXT

It is estimated that more than 346 million people worldwide have diabetes mellitus . By the year 2030, it is predicted that diabetes will become the seventh leading cause of death in the world. Development of chronic kidney disease (CKD) in patients with diabetes adds significantly to the morbidity and mortality and significantly increases health care costs, even before the development of end stage renal disease (ESRD). Evidence  acquisitions: Directory of Open Access Journals (DOAJ), Google Scholar, Pubmed (NLM), LISTA (EBSCO) and Web of Science have been searched.

RESULTS

Diabetic nephropathy (DN) is increasing rapidly worldwide. It is the leading cause of new cases of ESRD in the USA.  Interestingly, although DN is the most common cause of ESRD in diabetic patients, diabetes mellitus is also an independent and strong risk factor for ESRD ascribed to causes other than DN (e.g. hypertensive nephropathy).

CONCLUSIONS

It is important to be aware of the pitfalls of using the urine albumin level in predicting development and progression of diabetic nephropathy in order to treat and advise the patients accurately.  Research into finding new markers is rapidly evolving but current progress makes it likely we will be using the urine albumin level for some years into the future.

Homozygous lecithin:cholesterol acyltransferase (LCAT) deficiency due to a new loss of function mutation and review of the literature

BACKGROUND

A case of homozygous familial lecithin:cholesterol acyltransferase (LCAT) deficiency with a novel homozygous LCAT missense mutation (replacement of methionine by arginine at position 293 in the amino acid sequence of the LCAT protein) is reported.

METHODS AND RESULTS

The probable diagnosis was suggested by findings of marked high density lipoprotein (HDL) deficiency, corneal opacification, anemia, and renal insufficiency. The diagnosis was confirmed by two dimensional gel electrophoresis of HDL, the measurement of free and esterified cholesterol, and sequencing of the LCAT gene.

CONCLUSIONS

In our view the most important aspects of therapy to prevent the kidney disease that these patients develop is careful control of blood pressure and lifestyle measures to optimize non HDL lipoproteins. In the future replacement therapy by gene transfer or other methods may become available.

Risk for ESRD in type 1 diabetes remains high despite renoprotection

Historically, patients with type 1 diabetes and macroalbuminuria had high competing risks: cardiovascular death or renal failure. Here, we assessed these risks in patients receiving therapies implemented during the last 30 years. Between 1991 and 2004, we enrolled 423 white patients with type 1 diabetes who developed macroalbuminuria (albumin excretion rate, ≥300 μg/min). With follow-up for 98% through 2008, ESRD developed in 172 patients (incidence rate, 5.8/100 person-years), and 29 died without ESRD (mortality rate, 1/100 person-years). The majority of these outcomes occurred between ages 36 and 52 years with durations of diabetes of 21 to 37 years. The 15-year cumulative risks were 52% for ESRD and 11% for pre-ESRD death. During the 15 years of follow-up, the use of renoprotective treatment increased from 56 to 82%, and BP and lipid levels improved significantly; however, the risks for both ESRD and pre-ESRD death did not change over the years analyzed. There were 70 post-ESRD deaths, and the mortality rate was very similar during the 1990s and the 2000s (11/100 person-years versus 12/100 person-years, respectively). Mortality was low in patients who received a pre-emptive kidney transplant (1/100 person-years), although these patients did not differ from dialyzed patients with regard to predialysis eGFR, sex, age at onset of ESRD, or duration of diabetes. In conclusion, despite the widespread adoption of renoprotective treatment, patients with type 1 diabetes and macroalbuminuria remain at high risk for ESRD, suggesting that more effective therapies are desperately needed.

Diabetic microvascular complications: possible targets for improved macrovascular outcomes

The results of recent outcome trials challenge hypotheses that tight control of both glycohemoglobin and blood pressure diminishes macrovascular events and survival among type 2 diabetic patients. Relevant questions exist regarding the adequacy of glycohemoglobin alone as a measure of diabetes control. Are we ignoring mechanisms of vasculotoxicity (profibrosis, altered angiogenesis, hypertrophy, hyperplasia, and endothelial injury) inherent in current antihyperglycemic medications? Is the polypharmacy for lowering cholesterol, triglyceride, glucose, and systolic blood pressure producing drug interactions that are too complex to be clinically identified? We review angiotensin-aldosterone mechanisms of tissue injury that magnify microvascular damage caused by hyperglycemia and hypertension. Many studies describe interruption of these mechanisms, without hemodynamic consequence, in the preservation of function in type 1 diabetes. Possible interactions between the renin-angiotensin-aldosterone system and physiologic glycemic control (through pulsatile insulin release) suggest opportunities for further clinical investigation.

In patients with type 1 diabetes and new-onset microalbuminuria the development of advanced chronic kidney disease may not require progression to proteinuria

We sought to study new-onset microalbuminuria, its progression, and the decline of renal function in patients with type 1 diabetes. Using a cohort of 109 patients who developed new-onset microalbuminuria in the first 4 years following enrollment in the 1st Joslin Kidney Study, we simultaneously tracked the change in their renal function and urinary albumin excretion. Of these, 79 patients were followed for an average of 12 years after microalbuminuria onset, wherein their glomerular filtration rate was estimated by the Modification of Diet in Renal Disease Study formula and compared with their microalbuminuria and proteinuria. The concordance between these outcomes was weak. Only 12 of the 23 patients who progressed to advanced (stage 3-5) chronic kidney disease developed proteinuria, which, in general, did not precede but accompanied the progression to advanced chronic kidney disease. The remaining 11 patients who developed advanced disease had persistent microalbuminuria or returned to normal albuminuria. Thus, we found that one-third of patients with type 1 diabetes developed advanced chronic kidney disease relatively soon after the onset of microalbuminuria and this was not conditional on the presence of proteinuria. Contrary to the existing concept of early nephropathy in type 1 diabetes, less emphasis should be placed on the mechanisms of progression to proteinuria and more placed on mechanisms initiating and promoting the early decline of renal function that eventually progresses to advanced chronic kidney disease.

Manifestation of renal disease in obesity: pathophysiology of obesity-related dysfunction of the kidney

Albuminuria in individuals whose body mass index exceeds 40 kg/m(2) is associated with the presence of large glomeruli, thickened basement membrane and epithelial cellular (podocyte) distortion. Obstructive sleep apnea magnifies glomerular injury as well, probably through a vasoconstrictive mechanism. Insulin resistance from excess fatty acids is exacerbated by decreased secretion of high molecular weight adiponectin from adipose cells in the obese state. Adiponectin potentiates insulin in its post-receptor signaling resulting in glucose oxidation in mitochondria. Recent studies of podocyte physiology have concentrated on the structural and functional requirements that prevent glomerular albumin leakage. The architecture of the podocyte involves nephrin and podocin, proteins that cooperate to keep slit pores between foot processes competent to retain albumin. Insulin and adiponectin are necessary for high-energy phosphate generation. When fatty acids bind to albumin, the toxicity to proximal renal tubules is magnified. Albumin and fatty acids are elevated in urine of individuals with obesity related nephrotic syndrome. Fatty acid accumulation and resistin inhibit insulin and adiponectin. Study of cytokines produced by adipose tissue (adiponectin and leptin) and macrophages (resistin) has led to a better understanding of the relationship between weight and hypertension. Leptin, is presumably secreted after food intake to inhibit the midbrain/hypothalamic appetite centers. Resistance to leptin results in excess signaling to hypothalamic sympathetics leading to hypertension. Demonstration of the existence of a cerebral receptor mutation provide evidence for a role in hypertension of a central nervous reflex arc in humans. Further understanding of obesity-related renal dysfunction has been accomplished recently using experimental models. Rapid weight loss following bariatric surgery may reverse renal pathology of obesity with restoration of normal blood pressure.

Renal hyperfiltration and the development of microalbuminuria in type 1 diabetes

OBJECTIVE

The purpose of this study was to examine prospectively whether renal hyperfiltration is associated with the development of microalbuminuria in patients with type 1 diabetes, after taking into account known risk factors.

RESEARCH DESIGN AND METHODS

The study group comprised 426 participants with normoalbuminuria from the First Joslin Kidney Study, followed for 15 years. Glomerular filtration rate was estimated by serum cystatin C, and hyperfiltration was defined as exceeding the 97.5th percentile of the sex-specific distribution of a similarly aged, nondiabetic population (134 and 149 ml/min per 1.73 m(2) for men and women, respectively). The outcome was time to microalbuminuria development (multiple albumin excretion rate >30 microg/min). Hazard ratios (HRs) for microalbuminuria were calculated at 5, 10, and 15 years.

RESULTS

Renal hyperfiltration was present in 24% of the study group and did not increase the risk of developing microalbuminuria. The unadjusted HR for microalbuminuria comparing those with and without hyperfiltration at baseline was 0.8 (95% CI 0.4-1.7) during the first 5 years, 1.0 (0.6-1.7) during the first 10 years, and 0.8 (0.5-1.4) during 15 years of follow-up. The model adjusted for baseline known risk factors including A1C, age at diagnosis of diabetes, diabetes duration, and cigarette smoking resulted in similar HRs. In addition, incorporating changes in hyperfiltration status during follow-up had minimal impact on the HRs for microalbuminuria.

CONCLUSIONS

Renal hyperfiltration does not have an impact on the development of microalbuminuria in type 1 diabetes during 5, 10, or 15 years of follow-up.

Serum concentrations of markers of TNFalpha and Fas-mediated pathways and renal function in nonproteinuric patients with type 1 diabetes

BACKGROUND AND OBJECTIVES

The aim of our study was to examine serum markers of the TNF and Fas pathways for association with cystatin-C based estimated glomerular filtration rate (cC-GFR) in subjects with type 1 diabetes (T1DM) and no proteinuria.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The study group (the 2nd Joslin Kidney Study) comprised patients with T1DM and normoalbuminuria (NA) (n = 363) or microalbuminuria (MA) (n = 304). Impaired renal function (cC-GFR <90 ml/min) was present in only 10% of patients with NA and 36% of those with MA. We measured markers of the tumor necrosis factor alpha (TNFalpha) pathway [TNFalpha, soluble TNF receptor 1 (sTNFR1), and 2 (sTNFR2)], its downstream effectors [soluble intercellular and soluble vascular adhesion molecules (sICAM-1 and sVCAM-1), interleukin 8 (IL8/CXCL8), monocytes chemoattractant protein-1 (MCP1), and IFNgamma inducible protein-10 (IP10/CXCL10)], the Fas pathway [soluble Fas (sFas) and Fas ligand (sFasL)], CRP, and IL6.

RESULTS

Of these, TNFalpha, sTNFRs, sFas, sICAM-1, and sIP10 were associated with cC-GFR. However, only the TNF receptors and sFas were associated with cC-GFR in multivariate analysis. Variation in the concentration of the TNF receptors had a much stronger impact on GFR than clinical covariates such as age and albumin excretion.

CONCLUSIONS

Elevated concentrations of serum markers of the TNFalpha and Fas-pathways are strongly associated with decreased renal function in nonproteinuric type 1 diabetic patients. These effects are independent of those of urinary albumin excretion. Follow-up studies are needed to characterize the role of these markers in early progressive renal function decline.

High-normal serum uric acid is associated with impaired glomerular filtration rate in nonproteinuric patients with type 1 diabetes

BACKGROUND AND OBJECTIVES

Early renal function decline begins before the onset of proteinuria in patients with type 1 diabetes. The association of elevated serum uric acid with advanced impaired renal function prompts an examination of its role in early renal function decline in patients before proteinuria develops.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with type 1 diabetes and normoalbuminuria or microalbuminuria were recruited to the Second Joslin Kidney Study. A medical history and measurements of BP, hemoglobin A1c, albumin excretion rate, and serum concentrations of uric acid and cystatin C were obtained. Estimated glomerular filtration rate was measured by a cystatin C-based formula.

RESULTS

We studied 364 patients with normoalbuminuria and 311 patients with microalbuminuria. Mean glomerular filtration rate in these groups was 119 and 99 ml/min, respectively. Mildly or moderately impaired renal function (<90 ml/min) was present in 10% of those with normoalbuminuria and 36% of those with microalbuminuria. In univariate and multivariate analyses, lower glomerular filtration rate was strongly and independently associated with higher serum uric acid and higher urinary albumin excretion rate, older age, and antihypertensive treatment.

CONCLUSIONS

Serum uric acid concentration in the high-normal range is associated with impaired renal function in patients with type 1 diabetes. Follow-up studies are needed to confirm that this level of serum uric acid is a risk factor for early renal function decline in type 1 diabetes and to determine whether its reduction would prevent the decline.

ERK regulates the hepatocyte growth factor-mediated interaction of Gab1 and the phosphatidylinositol 3-kinase

Based on our previous observations that active ERK associates with and phosphorylates Gab1 in response to HGF, and the prediction that the ERK phosphorylation site is adjacent to one of the phosphatidylinositol 3-kinase (PI3K) SH2 binding motifs, we examined the possibility that ERK phosphorylation can regulate the Gab1/PI3K association. The HGF-mediated association of Gab1 with either full-length GST-p85 or its isolated N- or C-terminal SH2 domains was inhibited by approximately 50% in the setting of ERK inhibition, a result confirmed by co-immunoprecipitation of the native proteins. A 14-amino acid peptide encoding (472)YVPMTP(477) (one of the major p85 binding sites in Gab1 and the predicted ERK phosphorylation site) was synthesized with either phosphotyrosine alone (pY), or phosphotyrosine + phosphothreonine (pYT). In both pull-down assays and competition assays, pYT demonstrated a higher affinity for p85 than did pY alone. Finally, examination of the phosphorylation state of Akt after HGF stimulation revealed that ERK inhibition resulted in a decrease in Akt activation at both 5 and 10 min. These results suggest that activated ERK can phosphorylate Gab1 in response to HGF stimulation and thereby potentiate the Gab1/PI3K association and subsequent PI3K activation.

Fibrinogen and factor VII levels improve with glycemic control in patients with type 1 diabetes mellitus who have microvascular complications

To determine whether the hypercoagulable state of patients with complications of diabetes can be reversed toward normal, a group of insulin-dependent individuals with proteinuria was treated with intensive insulin protocols. A statistically significant (P<.001) improvement in control of diabetes was achieved (mean +/- SEM glycosylated hemoglobin, 9.51% +/- 0.35% at baseline to 8.36% +/- 0. 39% at 12 months; and mean +/- SEM advanced glycosylated end products, 14.8 +/- 2.8 U/mL at baseline to 8.4 +/- 1.5 U/mL at 12 months). There were statistically significant decreases in 2 procoagulant factors: mean +/- SEM baseline elevated plasma factor VII, 128.69% +/- 5.63% at baseline to 106.24% +/- 3.43% at 12 months (P =.002); and mean +/- SEM plasma fibrinogen, 12.3 +/- 0.7 micromol/L (417.3 +/- 24.7 mg/dL) at baseline to 10.2 +/- 0.7 micromol/L (348.8 +/- 22.6 mg/dL) at 12 months (P =.04). Throughout the study, lipid fractions did not change significantly. Because plasma factor VII and fibrinogen concentrations were elevated while cholesterol and triglyceride concentrations were not, more attention should be paid to procoagulants as markers for thromboembolic complications in diabetic patients undergoing intensive insulin therapy.

Improved glycemic control and platelet function abnormalities in diabetic patients with microvascular disease

Patients with diabetes mellitus have a variety of platelet and coagulation system dysfunctions. At least theoretically, these can contribute to microvascular complications. Intensive glycemic control has been demonstrated to decrease microvascular complications in type 1 diabetics. We studied 16 patients with type 1 diabetes mellitus (11 men and five women; mean age, 39 years) with albuminuria greater than 0.1 g/d and/or proteinuria greater than 0.3 g/d and a creatinine clearance rate higher than 30 mL/min. They received a regimen including three to four injections of insulin per day with or without a weekly infusion of intravenous insulin, and were evaluated for 6 months. We compared the plasma level of von Willebrand factor, platelet aggregation responses to adenosine diphosphate (ADP), epinephrine, and collagen, and platelet adhesion at the beginning of the study and at follow-up intervals. Glycemic control improved significantly. There were no significant differences in the platelet aggregation responses to ADP (1.59 +/- 0.34 v 1.88 +/- 0.23 mmol/L, P = .3; normal, 4.6 +/- 0.2), epinephrine (0.50 +/- 0.20 v 1.11 +/- 0.31 mmol/L, P = .06; normal, 7.6 +/- 1.5), or collagen (92.4 +/- 6.61 v 82.60 +/- 3.78 seconds, P = .6; normal, 79.1 +/- 3.1) or in platelet adhesion (126.31 +/- 16.95 v 195.08 +/- 30.2 platelets, P = .34; normal, 68.6 +/- 1.4). Baseline von Willebrand factor increased, but not significantly (166.38% +/- 10.6% v 142.72% +/- 14.73%, P = .21; normal, 102.0% +/- 6.0%). In type 1 diabetic patients with established microvascular complications of nephropathy, a statistically significant improvement in glycemic control did not improve the in vitro platelet function abnormalities. Improved glycemic control delays the progression of microvascular disease through mechanisms not measured by tests of platelet function.

Activated ERK2 interacts with and phosphorylates the docking protein GAB1

Grb2-associated binder 1 (GAB1) is a docking protein found to associate with the activated c-MET receptor via the MET-binding domain (MBD) and appears to be critical for the tubulogenic actions of this receptor. Pull-down experiments with bacterially expressed MBD and full-length GAB1 revealed the presence of c-MET as well as phosphorylated ERK2 (pERK2). By using purified pERK2 and non-pERK2, we found that GAB1 associates exclusively with the phosphorylated form of the enzyme and that this association does not require mediation by a third protein. When epitope-tagged GAB1 was co-transfected with constitutively active MEK1 into A293 cells, co-immunoprecipitation of GAB1 and pERK2 was observed, demonstrating that this interaction can occur in intact cells. In vitro, both the MBD and full-length GAB1 were found to be substrates for activated ERK2. In intact cells, epitope-tagged GAB1 was found to be basally phosphorylated on serine with an increase following co-transfection with constitutively active MEK1 and the appearance of novel phosphorylation sites detected by phosphopeptide mapping. Thus, it appears that GAB1 can associate directly with phosphorylated ERK2 via the MET-binding domain and that GAB1 then acts as a substrate for the enzyme.