[Campylobacter: a vintage pathogen to the fore].

Campylobacteriosis is caused by Gram bacteria. Most common species are C. jejuni and C. coli. Campylobacteriosis is a rare cause of sepsis, and in some European countries it is more common than salmonellosis, becoming a public health problem. We have treated a 66-year-old patient, hypertensive, ischemic cardiopathic, scheduled for coronary angiography, hospitalized with AKI, in a state of shock after some days of acute diarrhea. Because of the pathogen's seasonal nature and the patient's clinical features, in addition to common coproculture also Campylobacter has been sought, and found. Treated with volume repletion and antibiotics, within one week normal kidney functions were fully restored. He had a coronary angiography a week after being discharged from the hospital.

[COVID-19 emergency management at the Nephrology and Dialysis Unit in Savona, Albenga and Cairo Montenotte].

Our Nephrology and Dialysis Unit includes three Haemodialysis Centres based in Savona, Albenga and Cairo Montenotte. These provide assistance to 150 patients. We have a Peritoneal Dialysis Clinic with 35 patients, two Post-Transplant Clinics with about 120 patients in follow-up in Savona and Albenga, and three Pre-Dialysis Clinics across the three locations. Finally, there is an autonomous hospital ward with 15 beds that has continued its activity, even if at reduced regimes. With this report we intend to share the strategy we used to prevent the spread of the SARS CoV-2 virus among the patients and the staff at our Unit, following the National, Regional and Corporate guidelines published during "Phase 1". We decided that the Haemodialysis Centres needed to remain a safe place. To insure this, medical and nursing staff and patients had to behave conscientiously and collaboratively, and according to the official Hospital guidance. Our main concern was to protect patients who, despite suffering complications and being at high risk because of their age, immunodepression and multiple comorbidities, were forced to leave their house three times a week to be treated with dialysis. The results of this strategy have ensured that, of the 150 patients undergoing haemodialysis, only 3 have been tested positive: no patients in Albenga, 2 in Savona and 1 in Cairo Montenotte, all of them lived and were infected in their nursing homes. Also, there was no positivity among any of the staff members across the three locations. Our results are extremely positive and confirm the validity that prevention and protection procedures had in the earlier stages of the pandemic.

[Multidisciplinary management of a typical case of acute kidney failure in the course of COVID-19 infection].

We report the case of a 68-year-old patient who arrived at the hospital with a fever and a cough for 7 days, a history of high blood pressure and chronic kidney failure stage 2 according to CKD-EPI (GFR: 62 ml/minute with creatinine: 1.2 mg/dl). Home therapy included lercanidipine and clonidine. A chest radiograph performed in the emergency department immediately showed images suggestive of pneumonia from COVID-19, confirmed in the following days by a positive swab for coronavirus. Kidney function parameters progressively deteriorated towards a severe acute kidney failure on the 15th day, with creatinine values of 6.6 mg/dl and urea of 210 mg/dl. The situation was managed first in the intensive care unit with CRRT cycles (continuous renal replacement therapy) and then in a "yellow area" devoted to COVID patients, where the patient was dialyzed by us nephrologists through short cycles of CRRT. In our short experience we have used continuous techniques (CRRT) in positive patients hemodynamically unstable and intermittent dialysis (IRRT) in our stable chronic patients with asymptomatic COVID -19. We found CRRT to be superior in hemodynamically unstable patients hospitalized in resuscitation and in the "yellow area". Dialysis continued with high cut-off filters until the normalization of kidney function; the supportive medical therapy has also improved the course of the pathology and contributed to the favorable outcome for our patient. During the COVID-19 pandemic, our Nephrology Group at Savona's San Paul Hospital has reorganized the department to better manage both chronic dialyzed patients and acute patients affected by the new coronavirus.

[Role of inflammation on renal anaemia]. / Ruolo dell'infiammazione nell'anemia renale.

It is well-known the central role of inflammation in the inhibition of erythropoiesis and iron availability in chronic kidney disease (CKD) patients with erythropoietin (EPO)-resistant anaemia. This inflammatory action is mediated by suppressive cytokines (i.e. IL-6, TNF-, INF-) inhibiting differentiation and proliferation activities of erythroid cells in the EPO-indipendent phase of erythropoiesis and stimulating hepcidin production for iron retention in reticulo-endothelial system and enterocytes. EPO resistance is associated with adverse outcomes, such as cardiovascular disease, faster progression to end stage renal disease and mortality. Treatment of the causes of EPO hyporesponsiveness including chronic inflammation results in an improvement of anaemia and a reduction in EPO requirements.

Apoptosis and myostatin mRNA are upregulated in the skeletal muscle of patients with chronic kidney disease.

Apoptosis and myostatin are major mediators of muscle atrophy and might therefore be involved in the wasting of uremia. To examine whether they are expressed in the skeletal muscle of patients with chronic kidney disease (CKD), we measured muscle apoptosis and myostatin mRNA and their related intracellular signal pathways in rectus abdominis biopsies obtained from 22 consecutive patients with stage 5 CKD scheduled for peritoneal dialysis. Apoptotic loss of myonuclei, determined by anti-single-stranded DNA antibody and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assays, was significantly increased three to fivefold, respectively. Additionally, myostatin and interleukin (IL)-6 gene expressions were significantly upregulated, whereas insulin-like growth factor-I mRNA was significantly lower than in controls. Phosphorylated JNK (c-Jun amino-terminal kinase) and its downstream effector, phospho-c-Jun, were significantly upregulated, whereas phospho-Akt was markedly downregulated. Multivariate analysis models showed that phospho-Akt and IL-6 contributed individually and significantly to the prediction of apoptosis and myostatin gene expression, respectively. Thus, our study found activation of multiple pathways that promote muscle atrophy in the skeletal muscle of patients with CKD. These pathways appear to be associated with different intracellular signals, and are likely differently regulated in patients with CKD.

Mechanisms of renal ammonia production and protein turnover.

Renal synthesis and excretion of ammonia are critical for efficient removal of acids from the body. Besides the rate of ammonia production, the intrarenal distribution of produced ammonia is a crucial step in the renal regulation of acid-base balance. Various acid-base disorders are associated not only with changes in ammonia production but also with its distribution between the urine and the renal veins. The final effect of ammonia production on acid-base balance largely depends on the events that determine the distribution of ammonia produced between urine and blood. Several factors, among which urine pH, urine flow, total ammonia production "per se" and renal blood flow may affect the percent of ammonia excreted into urines in humans with different acid-base disturbances. Among these factors, urine pH is the most important. An additional effect of stimulated ammoniagenesis is kidney hypertrophy. In tubule epithelial cells, the associated increase in ammonia production, rather than the acidosis per se, is responsible for favoring tubular hypertrophy. This effect is related to the inhibition of protein degradation, owing to changes in lysosomal pH and cathepsin activity, without effects on cell cycle. Both changes of PI-3 kinase pathway and the suppression of chaperone-mediated autophagy are candidate mechanism for ammonia-mediated inhibition of protein degradation in tubule cells. Available data in humans indicate that the response of kidney to metabolic acidosis includes both changes in amino acid uptake and suppression of protein degradation. The latter effect is associated with the increase in ammonia excretion and partition into the urine.

Effects of uremia and inflammation on growth hormone resistance in patients with chronic kidney diseases.

Resistance to the anabolic action of growth hormone may contribute to the loss of strength and muscle mass in adult patients with chronic kidney disease. We tested this hypothesis by infusing growth hormone in patients to levels necessary to saturate hormone receptors. This led to a significant decrease of plasma potassium and amino acid levels in control and hyperkalemic patients with chronic kidney disease. These effects were completely or partially blunted in patients with elevated C-reactive protein levels. In forearm perfusion studies, growth hormone caused a further decrease in the negative potassium and protein balance of hemodialysis patients without inflammation but no effect was seen in patients with inflammation. Only IL-6 levels and age were found to be independent correlates in these growth hormone-induced variations in plasma potassium and blood amino acids. This shows that although a resistance to pharmacologic doses of growth hormone is not a general feature of patients with chronic kidney disease, there is a subgroup characterized by blunted growth hormone action. Our results support the hypothesis that uremia with inflammation, but not uremia per se, inhibits downstream growth hormone signaling contributing to muscle atrophy.

Kidney and splanchnic handling of interleukin-6 in humans.

Chronic elevation of circulating Interleukin-6 (IL-6) is observed in elderly individuals as well as in several illnesses, including chronic kidney diseases. A number of cells and tissues possess the ability to metabolize significant amounts of IL-6 in vitro. However, information on signals and mechanisms by which IL-6 is removed from blood in humans is still incomplete. To assess the individual role of splanchnic organs and kidney on IL-6 inter-organ exchange we used the IL-6 mass-balance technique across the hepato-splanchnic bed and kidney in six subjects with normal renal and liver function undergoing diagnostic venous catheterizations. Both in the hepatic and renal veins IL-6 levels were significantly lower (p=0.041 and 0.038, respectively), than in the artery. The fractional extraction of IL-6, i.e., the percentage of arterial IL-6 extracted after a single pass, was greater across the splanchnic organs (18%) than across the kidney (8%). Accordingly, IL-6 plasma clearance across splanchnic organs was greater than across the kidney and the sum of kidney and splanchnic removal accounted for as much as 63% of the estimated adipocyte IL-6 release. Our data demonstrate that, although the individual contribution to removal is different, both splanchnic organs and kidneys affect in a significant way the disposal of IL-6 in humans. According, both liver and kidney dysfunction could affect the handling of this proinflammatory cytokine and favour a chronic inflammatory response.

Causes of hyperhomocysteinemia in patients with chronic kidney diseases.

Plasma homocysteine (Hcy) levels are increased significantly in patients with moderate renal failure and increase markedly in patients with end-stage renal disease. An increase in plasma Hcy level theoretically could be caused by an increased production rate (ie, transmethylation), a decreased rate of removal by transsulfuration or remethylation, or a decrease in the excretion of Hcy. Current evidence indicates that the major mechanism for hyperhomocysteinemia in renal failure is a decrease in Hcy removal from the body. However, it is debated whether this effect is the result of a decrease in the renal metabolic clearance or a result of extrarenal metabolic changes. The human kidney plays a major role in the removal of several aminothiols or Hcy-related compounds from the circulation (eg, cysteine-glycine, glutathione, AdoMet, and AdoHcy). However, the glomerular filtration of Hcy seems to be restricted because of protein binding. Besides glomerular filtration, the normal kidney can remove Hcy by plasma flow and peritubular uptake. Although in the low normal range in absolute terms, the flow through the transsulfuration pathway is reduced if related to Hcy levels in uremia; in addition, the remethylation pathway also is impaired. Besides the potential effect of the reduced renal mass on Hcy removal, available evidence suggests the occurrence of a generalized down-regulation of the methionine cycle and catabolism in uremia. AdoHcy, sulfate, and dimethylglycine currently are being investigated as retained solutes that can inhibit 1 or more pathways of Hcy metabolism. In addition, the high Hcy levels decrease in malnourished end-stage renal disease patients and change according to nutrient intake and several other nutritional parameters, indicating that circulating Hcy levels become an expression of nutritional status.