COVID-19 and kidney: role of SARS-CoV-2 infection in the induction of renal damage.

OBJECTIVE: SARS-CoV-2 causes acute respiratory disease, interstitial and alveolar pneumonia, and involves numerous organs and systems such as the kidney, heart, digestive tract, blood, and nervous system. We aimed to evaluate the incidence of renal manifestations in patients diagnosed with COVID-19 infection. PATIENTS AND METHODS: We performed a monocentric, cross-sectional, observational study, conducted on 114 patients with SARS-CoV-2. Clinical and laboratory parameters [renal function, serum electrolytes, inflammatory state, blood gas analysis, Interleukin 6 (IL-6) and urinalysis] were evaluated. The same values were checked out after two months (T1), however after negativization. RESULTS: We enrolled 114 patients (59 males) with a mean age of 63.8 ± 13.9 years. We found hematuria in 48 patients (55.8%), proteinuria in 33 patients (38.4%), leukocyturia in 61 patients (70.9%), acute kidney injury (AKI) in 28 patients (24.6%), AKI in chronic kidney disease (CKD) in 24 patients (21.1%). Moreover, we found a significant increase of inflammatory indexes as C Reactive Protein (CRP), lactic dehydrogenase (LDH), alpha 1 and alpha 2 globulins with a subsequent reduction at T1 (p = 0.016, p < 0.001, p = 0.005, p = 0.007; respectively). Hemoglobin and erythrocyte values significantly decreased (p < 0.001, p = 0.003, respectively), and we found lymphopenia (p < 0.001). Also, we found elevated levels of the D-Dimer (p < 0.001) and a significant increase in the International Normalized Ratio (INR) (p = 0.038). We also showed a significant improvement after negativization in oxygen partial pressure (p = 0.001) and oxygen saturation (p < 0.001) and a significant increase in pH (p = 0.018) and bicarbonate concentration (p = 0.042). Moreover, we found a significant increase in IL-6 (p = 0.004). Also, we reported mild hyponatremia and hypokalemia with subsequent significant recovery (p < 0.001, p < 0.001, respectively) and mild hypochloremia with a recovery to the limits of statistical significance (p = 0.053). At the entrance, we found an increase in serum glucose with a significant reduction during recovery (p < 0.001). CONCLUSIONS: The prevalence of AKI and/or CKD and/or abnormal urinalysis in patients diagnosed with COVID-19 on admission seems to be high and appears as a negative prognostic factor. Urinalysis appears to be very useful in unveiling the potential kidney impairment of COVID-19 patients; therefore, urinalysis could be used to reflect and predict the disease severity. We also recommend a careful evaluation of metabolic alterations, inflammatory states, and electrolytic disorders in COVID-19 patients.

Literature review on the cross-link between ocular and renal disease: renin angiotensin aldosterone system is a main actor.

OBJECTIVE: Chronic kidney disease (CKD) and ocular disease share several cardiovascular risk factors as well as pathogenetic mechanisms having Renin-Angiotensin-Aldosterone System (RAAS) as main actor. Moreover, kidney and eyes have common genetic and embryonic origin. In this literature review, we present main evidence supporting this association for early identifying diseases affecting both systems and evaluating potential multi-target therapeutic strategies. MATERIALS AND METHODS: We performed a literature review of the current peer-reviewed English-language randomized controlled studies (RCTs), reference lists of nephrology or ophthalmology textbooks, review articles and relevant studies with ocular or eye and kidney or renal diseases as keywords until March 2020. Prospective and retrospective studies as well as meta-analyses and latest systematic reviews were included. RESULTS: We evaluated a total of 683 records, finally selecting 119 articles related to ocular and renal diseases. Records were divided into two areas: chronic and acute kidney disease and ocular or eye diseases. Some of the examined studies were discarded for population biases/intervention or deemed unfit. CONCLUSIONS: Based on our results, we conclude that there is evidence of a clear association between kidney and eye diseases, being this cross-link mainly based on RAAS dysregulation. Our review suggests that it may be useful to screen CKD patients for associated ocular diseases, such as cataract, glaucoma, diabetic retinopathy and age-related macular degeneration. A comprehensive study of CKD and proteinuric patients should include careful eye examination. Renal impairment in young patients should prompt a search for ocular disease, such as TUNA syndrome or oculo-renal syndrome, in particular if family history of concurrent ocular and renal disease is present. Anti-RAAS agents are mostly recommended in patients with renal and ocular impairment.

Screening of QTc interval and global autonomic activity in autosomal dominant polycystic kidney disease and atherosclerotic renal artery stenosis hypertensive patients.

OBJECTIVE: Arterial hypertension (AH) represents a major risk factor for cardiovascular disease and is associated to several complications, such as prolonged corrected QT (QTc) interval and impaired heart rate variability (HRV). Secondary causes of AH include autosomal dominant polycystic kidney disease (ADPKD) and atherosclerotic renal artery stenosis (ARAS), both known to be related to arrhythmic risk and autonomic imbalance. The aim of the study is to evaluate whether global autonomic activity and QTc interval differently affect ADPKD and ARAS hypertensive patients. PATIENTS AND METHODS: An observational study was performed on 59 patients: 16 ADPKD patients and 19 diagnosed with ARAS, compared to 24 healthy controls (HC). All patients underwent clinical evaluation, biochemical lab tests, 24-hour electrocardiogram (ECG) and renal Doppler ultrasound. HRV was assessed through the analysis of 24-hour ECG to detect standard deviation of normal-to-normal RR intervals (SDNN). QTc interval was defined as prolonged when > 440 msec. RESULTS: SDNN was significantly lower in ADPKD and ARAS patients than HC (p < 0.0001) and no significant differences were found between ADPKD and ARAS patients (p > 0.05). QTc was found significantly higher in ARAS patients than HC (p = 0.001) and in ARAS patients than ADPKD patients (p = 0.004). CONCLUSIONS: The pathogenesis of hypertension in ADPKD and ARAS patients is related to the activation of the renin angiotensin aldosterone system (RAAS). In ADPKD, cyst enlargement leads to kidney ischemia and renin release, associated to endothelial dysfunction, low nitric oxide and sympathetic tone activation. Differently, reduction in renal perfusion pressure activates RAAS and renal adrenergic nerves in ARAS patients. We can speculate that prolonged QTc interval is more present in ARAS vs. ADPKD hypertensive patients due to a greater activation of RAAS. We suggest adding 24-hour HRV evaluation in association with traditional risk factors in course of ADPKD and ARAS hypertension to better stratify cardiovascular risk in these groups of patients.

Increase of renal resistive index and mineral metabolism disorder in patients with acute coronary syndrome with preserved renal function.

OBJECTIVE: Coronary artery disease is one of the first causes of death in the Western world; for this reason, it is essential to identify new, systemic, non-invasive and low-cost cardiovascular risk markers. The acute coronary syndrome includes ST-Elevation Myocardial Infarction (STEMI) and Non-ST-Elevation Myocardial Infarction (NSTEMI), based on ECG findings. We aimed to evaluate Renal Resistive Index (RRI) as a marker of cardiovascular risk and assess the associations with other cardiovascular risk factors (metabolic indexes, mineral metabolism disorders and endothelial dysfunction and atherosclerosis markers) in STEMI and NSTEMI patients. PATIENTS AND METHODS: Clinical, laboratory and instrumental examinations as metabolic and inflammation indexes, markers of atherosclerosis and endothelial dysfunction (renal function, mineral metabolism disorders, inflammation indexes, Intima Media Thickness (IMT), Ankle Brachial Pressure Index, Left Ventricular Mass Index, Relative Wall Thickness) were performed. RESULTS: Eighty-one patients with STEMI and NSTEMI were enrolled. We showed a significant positive correlation between RRI and age (p<0.01), intact parathyroid hormone (p<0.01) and IMT (p<0.01), as well as a significant negative correlation between RRI and body surface area (BSA) (p=0.02), estimated Glomerular Filtration Rate (eGFR) (p<0.01), serum calcium (p<0.01) and 25-hydroxy-vitamin D (p=0.03). Moreover, we found a significant correlation between RRI and male patients (p<0.01), coronary artery disease history (CAD) (p=0.049), hypertension (p=0.025) and left ventricular eccentric hypertrophy (LVEH) (p=0.047). CONCLUSIONS: Our study showed an association between RRI and the main traditional and non-traditional cardiovascular risk factors involved in atherosclerosis pathogenesis, such as age, BSA, hypertension, male sex, CAD history, mineral metabolism disorders and LVEH, in patients with preserved renal function. Moreover, we found a significant correlation between RRI and eGFR, suggesting that RRI could be useful in the evaluation of both renal function and progression of renal damage, even in an early stage with a conserved or only slightly reduced kidney function. We also showed a significant correlation with some markers of systemic atherosclerosis such as IMT and LVEH. For a more precise assessment of prognosis and cardiovascular risk in patients with high cardiovascular mortality, we suggest performing a systematic RRI evaluation, considering the non-invasive nature of the procedure, its reproducibility, easy execution, and low costs.

Hepatitis B vaccination in haemodialysis patients: an underestimated problem. Factors influencing immune responses in ten years of observation in an Italian haemodialysis centre and literature review.

OBJECTIVES: Despite universal infection control precautions, the risk of hepatitis B virus (HBV) infection in patients on chronic haemodialysis (HD) remains high. For this reason anti-HBV vaccination is recommended in these subjects. In hemodialyzed patients vaccinal response is often suboptimal and it's not clear what factors may influence it. STUDY DESIGN: The aim of our study is to assess the influence of some clinical and laboratory factors on seroconversion rate after anti HBV vaccination in a cohort of patients on maintenance HD. METHODS: We analysed 60 patients on regular HD, 40 men and 20 women (age 64±12 years, range 40-88 years), immunized with Engerix B ® vaccine, followed for an average time of 62 month (12-120 months). For each patient the following data were collected: age, serum albumin (sAlb), Blood urea nitrogen before HD session (BUN), age at vaccination, dialysis vintage, presence of systemic disease, type of vascular access, dialysis modality. Correlation between these factors and anti Hbs titer was estimated with multiple regression analysis. RESULTS: Anti-Hbs seroconversion rate ( Anti Hbs > 10 IU/l) was 77%. Better rate of seroconversion (86%) was observed in patients with arteriovenous fistula (AVF) and serum albumin > 3,5 g/dL (93%), while higher rate of not responders (50%) in patients with systemic diseases. The only parameter correlated to anti Hbs titer was sAlb (p =0,0012). sAlb was correlated to age in all patients (p=0,01) and age was correlated to higher anti Hbs titer in the responder group (p=0,018). DISCUSSION: In our experience an early vaccination, when patients on chronic HD are younger and in better nutritional conditions, improves anti-HBV response.

Dialysis-associated pseudoporphyria successfully treated with vitamin D. Report of two cases.

Pseudoporphyria refers to a rare bullous dermatosis characterized by the clinical and histological features of porfiria cutanea tarda without abnormalities in porphyrin metabolism. The pathogenesis is heterogeneous and several exogenous factors may promote the bullous lesion formation, including medications, end stage renal disease, dialysis and tanning beds. Regarding treatment of this condition, in literature different therapy have been reported, such as glutathione and his precursor N-acetylcysteine, which presents anti-oxidant properties; however even more toxic drugs, such as chloroquine, are used. Moreover, in patients with drug-induced PP discontinuation of the offending agent, if possible, is a crucial aspect of the clinical management. We report two cases of dialysis patients presenting blisters on extremities, which healed with the avoidance of UV exposure and oral Vitamin D supplementation. Interestingly Vitamin D despite the lack of antioxidant properties led to a completely resolution of PP in both our patients within 30 days. A possible explanation of this finding is that Vitamin D, playing a key role in the regulation of serum Ca2+, can modulated cadherin-cadherin interactions and led to healing of pseudoporphyria bullous lesions. Finally we highlight the prominent role of UV-exposure in PP elicitation thus a good photoprotection is essential for all patients with pseudoporphyria.

Limberg skin flap for treatment of necrosis and bleeding at haemodialysis arteriovenous angioaccess puncture sites.

OBJECTIVE: To assess the efficacy of a Limberg skin flap to treat non-infected necrosis and bleeding at angioaccess puncture sites. METHODS: Retrospective analysis of 40 selected (no infection, necrosis <20 mm diameter) patients (25 arteriovenous fistulae [AVF], 15 grafts) treated between 1998 and 2012 by rhomboid excision, vessel repair, and a locally rotated full-thickness Limberg skin flap together with early postoperative percutaneous transluminal angioplasty (PTA; n = 23/40). Success was defined as wound healing and angioaccess patency without complications. RESULTS: Success rates at 1 and 6 months were 96% (24/25) and 76% (19/25), respectively, for AVF, and 80% (12/15) and 40% (6/15) for arteriovenous grafts. Complications included flap necrosis (n = 2), graft thrombosis (n = 4), minor sepsis (n = 1), death (n = 2), and new puncture site necrosis (n = 3). Four patients were lost to follow-up. CONCLUSIONS: Vessel or graft repair, PTA for distal stenoses and local debridement followed by a Limberg skin flap for tissue defects prevented further bleeding and maintained vascular access patency in 25/40 (62%) patients.

Hyponatremia and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH).

The syndrome of inappropriate ADH secretion (SIADH), also recently referred to as the "syndrome of inappropriate antidiuresis", is an often underdiagnosed cause of hypotonic hyponatremia, resulting for instance from ectopic release of ADH in lung cancer or as a side-effect of various drugs. In SIADH, hyponatremia results from a pure disorder of water handling by the kidney, whereas external Na+ balance is usually well regulated. Despite increased total body water, only minor changes of urine output and modest edema are usually seen. Renal function and acid-base balance are often preserved, while neurological impairment may range from subclinical to life-threatening. Hypouricemia is a distinguishing feature. The major causes and clinical variants of SIADH are reviewed, with particular emphasis on iatrogenic complications and hospital-acquired hyponatremia. Effective treatment of SIADH with water restriction, aquaretics, or hypertonic saline + loop diuretics, as opposed to worsening of hyponatremia during parenteral isotonic fluid administration, underscores the importance of an early accurate diagnosis and careful follow-up of these patients.

Extracapillary glomerulonephritis during etanercept treatment for juvenile psoriatic arthritis.

Juvenile psoriatic arthritis was diagnosed in a girl of 15 and a half years old, who presented with severe poly-arthritis and psoriasis. Treatment with etanercept 25 mg by subcutaneous injections, twice a week was started. After 5 months of treatment, she developed microscopic hematuria, proteinuria and progressive acute renal failure with anaemia and hypertension. Renal histology, IF, and EM findings were consistent with severe extracapillary crescentic pauciimmune glomerulonephritis. The histology findings, the onset of renal symptoms after beginning treatment with etanercept, and the absence of any abnormality in the urine tests before administration of the drug, support the hypothesis of a rare case of secondary nephropathy due to treatment with an anti-TNF-alpha drug.

Acute renal failure due to amiodarone-induced hypothyroidism.

Renal alterations in hypothyroidism include decreased glomerular filtration rate and renal plasma flow. We herein report a case of amiodarone -induced hypothyroidism associated with a rapid decrease of renal function, reversible upon amiodarone withdrawal. A 72-year-old man presented to our clinic in August 2007 reporting a recent deterioration of renal function. Ten weeks before he was admitted to another hospital for a supraventricular tachyarrhythmia treated with carvedilol 12.5 mg/day and amiodarone 400 mg/day. On admission, laboratory tests revealed altered renal function (serum creatinine 6 mg/dl, blood urea nitrogen 78 mg/dl) and severe hypothyroidism (free T4 0.27 pg/ml, free T3 1.49 pg/ml, TSH 183.36 mU/l). Amiodarone and carvedilol were stopped, while levothyroxine 75 mcg/die was started. After three months renal function had completely recovered to 1.9 mg/dl, BUN 28 mg/dl, with concurrent improvement of thyroid function free T4 14.2 pg/ml, free T3 6.4 pg/ml, TSH 15.5 mU/l.

Renal limited Wegener's granulomatosis.

Differential diagnosis in patients presenting with fever of unknown origin (FUO) is often difficult because infectious diseases, neoplasms, infective endocarditis or systemic autoimmune diseases may all be responsible for the condition. Furthermore, vasculitis may generate typical, atypical or limited syndromes depending on the extent of vascular involvement. Here, we report the case of a 73-year-old man with FUO and renal failure due to a rare variant of Wegener's granulomatosis, limited to the kidneys.

Rhabdomyolysis due to severe hypokaliemia in a Crohn's disease patient after budesonide treatment.

Patients with Crohn's disease may experience several non-digestive complications, including muscle disorders. Rabdomyolysis has rarely been reported in patients with inflammatory bowel disease, however a number of factors may cause muscular damage in this setting. We report the case of a young woman with Crohn's disease who developed a severe, symptomatic skeletal muscle damage associated with severe hypokaliemia. Reversal of the potassium levels to normal ranges led to clinical resolution. The possible causes that might have lead to hypokalemia development and subsequent rhabdomyolysis are discussed with special emphasis for the potential causative role of medical treatment, especially budesonide for which similar side effects have been previously reported. Physicians should be aware that hypokalemia is possible in the setting of Crohn's disease and muscle damage can present as a complication.

[Role of uric acid in hypertension and in the progression of chronic renal disease]. / Ruolo dell'acido urico nell'ipertensione arteriosa e nella progressione delle nefropatie.

In humans, uric acid (UA) is the main urinary metabolite of purines, whereas in other species (avians) it is the chief nitrogen compound excreted in the urine. The absence of uricase, due to nonsense or splice mutations occurring during the evolution of primates, results in blood urate levels much higher in humans than in other mammalians. This could have favorable implications, including protection from oxidative damage, as well as possibly allowing better blood pressure (BP) control in settings of low dietary Na+ intake. UA is a stimulus of the renin-angiotensin system (RAS). Moreover, blood UA levels are a major marker of proximal tubular function and overall volume status. On the other hand, hyperuricemia is a co-factor in Na+ -sensitive arterial hypertension, a marker and perhaps itself responsible for microvascular and systemic damage through RAS stimulation, inhibitory effects on endothelial cells, and the proliferation of perivascular smooth muscle cells. Recent studies in rats rendered hyperuricemic through administration of oxonic acid demonstrate the induction of hypertension and severe microvascular damage when associated with subtotal nephrectomy or chronic cyclosporine treatment. The opportunity to pharmacologically manipulate blood UA levels through inhibitors of synthesis (allopurinol), uricosuric agents (benziodarone), or recombinant urate oxidase (rasburicase) provides a relevant therapeutic potential in UA metabolism disorders, tumor lysis syndrome, and possibly in essential hypertension, as well as chronic progressive renal disease.

[Glomerulonephritis and renal sclerosis: new therapeutic proposals (review)]. / Glomerulonefriti e sclerosi renale: nuove proposte terapeutiche.

The treatment of immuno-mediated glomerulonephritides is presently based upon a limited series of drugs. Albeit evidence-based medicine relies solely upon controlled trials, there is a need to follow new perspectives with an open mind, since they may lead to tomorrow's therapy. Several original and innovative approaches to treat inflammatory glomerular diseases have been recently reported, including drugs designed to limit the effect of pro-inflammatory and pro-sclerotic cytokines (recombinant monoclonal antibodies, receptor antagonists, gene therapy providing viral transfection of genes, antisense oligonucleotides, aptamers, inhibition of transcription factors, active immunization). Moreover, newer options are being proposed, as in the case of enhancing natural anti-inflammatory cytokines or intracellular signalling limiting inflammation. Some of these proposals, which are briefly reviewed in this article, are likely to enter soon clinical investigation and to become in the next future standard treatment for glomerular diseases.

[Mechanisms of repair after renal injury]. / Meccanismi di riparazione del danno renale.

Recovery from kidney injury through repair mechanisms often linked to inflammation is conditioned by nature and severity of the insult. In the assessment of kidney repair, functional recovery should be kept distinct from structural repair: compensatory hypertrophy/function of intact nephrons often masks the inability of the kidney to heal or replace damaged structures. The mechanisms of repair reflect three degrees of injury, differently handled by the kidney. First, repair of DNA damage is accomplished through proofreading DNA polymerases, along with other controls for sequence misalignment / nucleotide replacement. If DNA cannot be repaired, cells carrying mutation(s) are disposed of through apoptosis, which is also critical to clearing damaged kidney cells and infiltrating leukocytes in acute and chronic ischemic, immunological, or chemical damage. A second mechanism of repair is linked to proliferation of surviving cells. At least 5 types of reparative proliferation are known to occur, some of which implicate stem cell immigration from distant reservoirs, followed by in situ differentiation. A third mode of repair could be referred to as structural repair, indeed limited in the human kidney by the absence of postnatal nephrogenesis. Recovery from acute tubular necrosis involves remodelling of the proximal tubule, with a strict requirement for integrity of the basement membrane. Contrary to the current dogma that only acute injury can be repaired, whereas chronic damage leads to irreversible loss of nephrons, evidence is emerging that some degree of renal remodelling occurs even in chronic renal disease, despite the occurrence of stabilized structural changes.

[Syndrome of inappropriate ADH secretion: a late complication of hemopoietic stem cell allograft]. / Sindrome da inappropriata secrezione di ormone antidiuretico: una complicanza tardiva del trapianto di cellule staminali emopoietiche.

An 11-year old boy with acute lymphoid leukemia underwent umbilical cord stem cell infusion. This was followed at day 15 by the onset of asymptomatic hypotonic isovolemic hyponatremia. The disorder could be attributed to a syndrome of inappropriate ADH secretion (SIADH), most probably related to the massive i.v. induction treatment with cyclophosphamide. The major causes and clinical variants of SIADH are reviewed, with particular emphasis on the complications of chemotherapy in hematological diseases. Worsening of hyponatremia during routine parenteral feeding, as opposed to normalization of plasma Na+ by infusion of hypertonic saline, emphasize the importance of early accurate diagnosis and careful follow-up of these iatrogenic sequelae of stem cell allograft.