Pathway from Acute Kidney Injury to Chronic Kidney Disease: Molecules Involved in Renal Fibrosis

Acute kidney injury (AKI) is one of the main conditions responsible for chronic kidney disease (CKD), including end-stage renal disease (ESRD) as a long-term complication. Besides short-term complications, such as electrolyte and acid-base disorders, fluid overload, bleeding complications or immune dysfunctions, AKI can develop chronic injuries and subsequent CKD through renal fibrosis pathways. Kidney fibrosis is a pathological process defined by excessive extracellular matrix (ECM) deposition, evidenced in chronic kidney injuries with maladaptive architecture restoration. So far, cited maladaptive kidney processes responsible for AKI to CKD transition were epithelial, endothelial, pericyte, macrophage and fibroblast transition to myofibroblasts. These are responsible for smooth muscle actin (SMA) synthesis and abnormal renal architecture. Recently, AKI progress to CKD or ESRD gained a lot of interest, with impressive progression in discovering the mechanisms involved in renal fibrosis, including cellular and molecular pathways. Risk factors mentioned in AKI progression to CKD are frequency and severity of kidney injury, chronic diseases such as uncontrolled hypertension, diabetes mellitus, obesity and unmodifiable risk factors (i.e., genetics, older age or gender). To provide a better understanding of AKI transition to CKD, we have selected relevant and updated information regarding the risk factors responsible for AKIs unfavorable long-term evolution and mechanisms incriminated in the progression to a chronic state, along with possible therapeutic approaches in preventing or delaying CKD from AKI.

Epidemiological Characteristics and Mortality Risk Factors Comparison in Dialysis and Non-Dialysis CKD Patients with COVID-19-A Single Center Experience

(1) Background: Despite some controversies between studies, chronic kidney disease (CKD) has a negative impact on COVID-19 outcomes, with patients presenting a higher mortality risk than in the general population. Studies have shown an association between COVID-19 severe cases and different inflammatory biomarkers. The aim of this study was to emphasize the epidemiological characteristics of CKD patients diagnosed with COVID-19 and to determine if the risk of mortality, and the severity of this infection might be influenced by different parameters. (2) Methods: Our retrospective study included CKD patients with COVID-19—362 in the non-dialysis group and 132 in the dialysis group. (3) Results: There were significant statistical differences between our groups regarding age (p < 0.001), hemoglobin (p < 0.001), interleukin-6 (p < 0.001), serum albumin (p = 0.016), procalcitonin (p = 0.002), ferritin (p < 0.001), and of course serum creatinine (p < 0.001). Even if the risk of death was higher in the dialysis group (Exp(b) = 1.839), the survival proportions were similar in both groups. (4) Conclusions: High values of hemoglobin, serum creatinine, and LDH at admission, age, length of hospital stay ≤ 10 days, and a pulmonary impairment > 25% are responsible for an adverse outcome in non-dialysis and dialysis patients diagnosed with COVID-19.

Magnesium—A More Important Role in CKD–MBD than We Thought

Chronic kidney disease (CKD) is associated with different complications, including chronic kidney disease–mineral and bone disorder (CKD–MBD), which represents a systemic disorder that involves the presence of different mineral or bone structure abnormalities (i.e., modification of bone turnover, strength, volume, etc.), including even vascular calcification development. Even if, over the years, different pathophysiological theories have been developed to explain the onset and progression of CKD–MBD, the influence and importance of serum magnesium level on the evolution of CKD have only recently been highlighted. So far, data are inconclusive and conflicting; therefore, further studies are necessary to validate these findings, which could be useful in developing a better, more adequate, and personalized management of CKD patients.

Uric Acid and Oxidative Stress-Relationship with Cardiovascular, Metabolic, and Renal Impairment

Background: The connection between uric acid (UA) and renal impairment is well known due to the urate capacity to precipitate within the tubules or extra-renal system. Emerging studies allege a new hypothesis concerning UA and renal impairment involving a pro-inflammatory status, endothelial dysfunction, and excessive activation of renin–angiotensin–aldosterone system (RAAS). Additionally, hyperuricemia associated with oxidative stress is incriminated in DNA damage, oxidations, inflammatory cytokine production, and even cell apoptosis. There is also increasing evidence regarding the association of hyperuricemia with chronic kidney disease (CKD), cardiovascular disease, and metabolic syndrome or diabetes mellitus. Conclusions: Important aspects need to be clarified regarding hyperuricemia predisposition to oxidative stress and its effects in order to initiate the proper treatment to determine the optimal maintenance of UA level, improving patients’ long-term prognosis and their quality of life.

MO385THE IMPACT OF SARS-COV-2 INFECTION ON MORTALITY IN CKD PATIENTS – A SINGLE-CENTER PILOT STUDY

Background and Aims

Since the beginning of 2019, once COVID-19 pandemic was declared, there is a keen interest in understanding the impact of SARS-CoV-2 infection on chronic kidney disease (CKD) patients, regarding the influence on CKD progression and the suitable therapy options, as most of the indicated medications are contraindicated for a glomerular filtration rate (GFR) below 30 ml/min, and, in addition, there is a little experience in dialyzed patients. The aim of our single-center pilot study is to determine the influence of SARS-CoV-2 infection on CKD patients’ (dialyzed or not) outcome and hospitalization rate.

Method

We evaluated the patients diagnosed with COVID-19, admitted in our Department between October and December 2020. The inclusion criteria were: age > 18 years old, diagnosis of CKD – predialysis and hemodialyzed patients. The exclusion criteria were: patients without pre-existing CKD. All included subjects signed the patients’ consent. To all included patients we performed the following tests: total blood count, erythrocyte sedimentation rate, C-reactive protein, fibrinogen, ferritin, serum free iron, serum creatinine, urea, uric acid, calcemia, total proteins, electrolytes and acid-base balance, urinary exams (including urine culture), coagulation and lipid profile, quantitative D-dimer, IL-6, procalcitonin, and imaging tests (CT, pulmonary Rx, abdominal ultrasonography). The patients were monitored by the infectious disease medical team that adjusted the therapy according to the patients’ lab and imagistic results. The specific treatment for SARS-CoV-2 infection included primary anti-interleukin receptor monoclonal antibody drugs (such as Anakinra, Tocilizumab), corticotherapy (dexamethasone), anti-retroviral therapy (remdesivir, favipiravir) only in hemodialyzed patients or in those presenting an eGFR > 30 mL/min, antibiotics, antifungal drugs, and oxygen-therapy. Usually, anti-interleukin receptor monoclonal antibody consisted in 7 doses, administrated every 48 hours. The dose of all other recommended drugs was adapted according to the patients’ eGFR.

Results

A total of 63 patients were admitted in our Department and were under our care, presenting medium or severe forms of SARS-CoV-2 infection. After applying the inclusion and exclusion criteria, only 38 patients were considered eligible: 21 male patients (mean age 63.52 ± 13.82 years), and 17 female patients (mean age 67.24 ± 12.83 years). 31.57% represented the percentage of death during the hospitalization (due to the severity of the disease, 4 patients died within 24 hours) in patients presenting heterogenous comorbidities, such as diabetes mellitus, hypertension, pre-existing glomerulonephritis and/or oncological pathologies; we also noticed that female gender represented 58.33% of the deceased patients. The mean hospitalization period in the deceased patients was 6.42 ± 5.38 days – 4 ± 3.21 days in female gender, and 9.8 ± 6.30 days in male gender.

Conclusion

Most of our patients, although diagnosed with medium and severe forms of SARS-CoV-2 infection, presented a favorable evolution, and an adequate response to the specific medication. We observed that most of the deceased cases were female patients, and compared to the male deceased subject, female deceased patients presented a lower period of hospitalization. Therefore, probably female CKD patients with comorbidities and diagnosed with COVID-19 are more predisposed to an unfavorable prognosis. Further and larger clinical trials are necessary to validate the impact of SARS-CoV-2 infection on mortality in CKD patients.

The Relationship between Advanced Oxidation Protein Products, Vascular Calcifications and Arterial Stiffness in Predialysis Chronic Kidney Disease Patients

Background and Objectives: Cardiovascular morbidity and mortality are increased in patients with chronic kidney disease (CKD). It is likely that the accumulation of uremic toxins resulting in increased oxidative stress (OS) is a major contributing factor, but no clear link has been identified. The purpose of this research is to establish if advanced oxidation protein product (AOPP) levels in the serum of predialysis patients are a contributing factor to vascular calcification and increased arterial stiffness. Materials and Methods: After obtaining the informed consent, 46 predialysis patients (CKD stages G3-G5) were included in the study. In order to identify vascular calcifications, hand and pelvic radiographs were performed. Valvular calcifications were identified using cardiac ultrasound. AOPP were measured using a commercially available ELISA kit. The relationships between serum AOPP values and biochemical parameters relevant in the evaluation of CKD patients were analyzed. In addition to identifying the differences in AOPP levels between patients with/without vascular or valvular calcifications, the research focused on describing the relationship between OS and arterial stiffness assessed by oscillometric pulse-wave velocity (PWV) measurement. Results: No significant relationship between serum AOPP and vascular or valvular calcifications was highlighted, but significant correlations of AOPP with C-reactive protein (p = 0.025), HDL-cholesterol levels (p = 0.04), HbA1c (p = 0.05) and PWV values (p = 0.02) were identified. Conclusions: The usefulness of (OS) measurement in clinical practice remains debatable; however, the relationship between AOPP and arterial stiffness could be valuable in improving cardiovascular risk assessment of patients with CKD.

Supersonic Shear Wave Ultrasonography for Assessing Tissue Stiffness in Native Kidney

Recent years have brought shear wave elastography to the attention of nephrologists as a non-invasive method for detecting kidney fibrosis and, therefore, as a potential tool for reducing the need for kidney biopsy. Few studies are performed on native kidney. We aimed to compare cortical stiffness, assessed by measuring Young's modulus (YM, kPa) with SuperSonic Imaging technology, in patients with various degrees of chronic kidney disease (CKD) compared with healthy individuals. Cortical stiffness was measured by two operators, in different sessions, in 32 patients with CKD stages 3-5 and 20 healthy individuals. Comparison between mean YM values in CKD and those in controls and also between the different stages of CKD was our primary objective. The influence of other possible confounders on YM readings was also investigated and analyzed. Mean YM was significantly greater in CKD patients than in controls. Estimated YM was not able to differentiate the stages of CKD, except stage 5. Intra-subject variability was greater in CKD than in controls. Body mass index was the most important confounder in multiple analyses, in both the CKD and control groups. Our results highlight a positive correlation between increased cortical stiffness and presence of CKD. Further studies are needed to validate this method for implementation in daily clinical practice.

Correlation Between Recombinant Human Erythropoietin Dose and Inflammatory Status in Dialysed Patients

Once recombinant human erythropoietin (r-HuEPO) was introduced in daily practice, huge steps were made in combating the adverse effects induced by anemia in chronic kidney disease population. Still, r-HuEPO resistance and the doses ensuring the maximum therapeutic benefit remain matters of debate. The aim of our study was to assess the correlation between the presence and the degree of inflammation and the r-HuEPO requirements in chronic dialysis patients. We conducted a 2 years prospective study on 146 patients undergoing chronic dialysis treated with r-HuEPO. Based on their average CRP (C-reactive protein) levels, obtained from repeated samplings at 3 months interval, 3 groups were formed; we noted in each group the average values of r-HuEPO prescribed to achieve the optimum hemoglobin levels according to the dialysis best practice guidelines and all the adverse effects of the therapy. A direct correlation was observed between CRP levels and r-HuEPO requirements in the first 2 groups of patients (CRP under 6 mg/L and CRP values 6-20 mg/L), with significant increase in r-HuEPO doses between groups (p [ 0.001); the third group, CRP values over 20 mg/dL, showed a minor, insignificant increase in average r-HuEPO doses compared to mild inflammation group (p = 0.199) and more adverse effects of the therapy (p [ 0.05). Inflammation is an important determinant of anemia in chronic dialysis patients and can induce an increase in the doses of r-HuEPO. However, prescribing excessive r-HuEPO doses is not the answer in severe inflammatory status, due to lack of response and possible adverse effects.

Sublingual desmopressin is efficient and safe in the therapy of lithiasic renal colic

PURPOSE

To evaluate the effects of newer sublingual desmopressin administration in lithiasic renal colic, alone or combined with a nonsteroidal anti-inflammatory drug (NSAID).

METHODS

Prospective single-blind study including an initial number of 249 patients with lithiasic renal colic was randomized as follows: group NSAID (71 patients) received ketorolac tromethamine (ketorolac) 30 mg im and sublingual placebo (vitamin C), groups D1 and D2 (57 and 62 patients) received sublingual desmopressin (Minirin Melt), 60 and 120 μg, respectively, whereas group C (59 patients) received a combination of 30 mg im ketorolac and 60 μg sublingual desmopressin. Pain intensity was assessed using the visual analogue scale before and thirty minutes after drug administration. Patients experiencing pain aggravation were rescued and excluded from the study.

RESULTS

Dropout incidence was higher in the NSAID group than in the groups treated with desmopressin in monotherapy or combined with ketorolac (p < 0.05). Pain intensity was diminished at least as potently by the monotherapy with desmopressin and ketorolac. The higher dose of desmopressin and the combination therapy decreased pain intensity with 56 and 59%, respectively, significantly more than the 47% decrease obtained with ketorolac alone (p < 0.05 and p < 0.001). Mean pain decrease was higher in the combination group (C) than in the NSAID or D1 groups (p < 0.001 and p < 0.05, respectively), suggesting drug additivity. Patients did not experience severe side effects.

CONCLUSIONS

Sublingual desmopressin is at least as potent as NSAID in the treatment of lithiasic renal colic. The combination of sublingual desmopressin and NSAID has additive analgesic effects.