Hantavirus Research in Finland.

The articles in this Special Issue, "Hantavirus Research in Finland", were published between 2021 and 2022 [...].

Haemodynamics of hyperthyroidism: increased cardiac work and findings related to vasodilatation.

OBJECTIVE: Hyperthyroidism increases cardiovascular morbidity and mortality, but the underlying mechanisms are not fully understood. In this study we compared non-invasive haemodynamics between 20 hyperthyroid patients and 60 euthyroid subjects. METHODS: The measurements were performed median 6 days after the initiation of antithyroid medication when the patients were still hyperthyroid. Three controls matched for age, sex, body mass index, and smoking status were selected for each patient. Recordings were performed during rest and passive head-up tilt using whole-body impedance cardiography, radial pulse wave analysis, and finger blood pressure measurements. RESULTS: Systolic and diastolic blood pressures in the aorta and radial artery were similar in hyperthyroid and euthyroid subjects, while finger blood pressure was 16/12 mmHg lower in hyperthyroidism (p<0.001). Pulse wave velocity and aortic pulse pressure were similar, but radial pulse pressure was ~5 mmHg higher in hyperthyroidism (p=0.040) due to augmented amplification (p=0.045). Systemic vascular resistance was reduced (-18%), whereas heart rate (+19 beats/min), cardiac index (+28%), and left cardiac work (+31%) were increased in hyperthyroidism (p<0.001). Subendocardial viability ratio, reflecting the balance between coronary perfusion and pressure load, was reduced by 19% in hyperthyroidism (p<0.001). Compared with euthyroid subjects, hyperthyroid patients presented with reductions in systolic and diastolic finger blood pressures (p<0.001), and higher increase in heart rate (p=0.014) during upright posture. CONCLUSIONS: Hyperthyroid patients exhibited hyperdynamic circulation, reduced vascular resistance, reduced peripheral but not central blood pressure, and higher pulse pressure amplification. Furthermore, left cardiac workload was increased in parallel with unfavourable changes in coronary perfusion conditions.

Targeted Treatment Reverses Increased Left Cardiac Work in Unilateral vs. Bilateral Primary Aldosteronism.

BACKGROUND: The incidence of cardiovascular complications may be higher in unilateral than bilateral primary aldosteronism (PA). We compared noninvasive hemodynamics after targeted therapy of bilateral vs. unilateral PA. METHODS: Adrenal vein sampling was performed, and hemodynamics recorded using radial artery pulse wave analysis and whole-body impedance cardiography (n = 114). In 40 patients (adrenalectomy n = 20, spironolactone-based treatment n = 20), hemodynamic recordings were performed after 33 months of PA treatment. RESULTS: In initial cross-sectional analysis, 51 patients had bilateral and 63 unilateral PA. The mean ages were 50.6 and 54.3 years (P = 0.081), and body mass indexes 30.3 and 30.6 kg/m2 (P = 0.724), respectively. Aortic blood pressure (BP) and cardiac output did not differ between the groups, but left cardiac work was ~10% higher in unilateral PA (P = 0.022). In the follow-up study, initial and final BPs in the aorta were not significantly different, while initial cardiac output (+13%, P = 0.015) and left cardiac work (+17%, P = 0.009) were higher in unilateral than bilateral PA. After median treatment of 33 months, the differences in cardiac load were abolished, and extracellular water volume was reduced by 1.3 and 1.4 l in bilateral vs. unilateral PA, respectively (P = 0.814). CONCLUSIONS: These results suggest that unilateral PA burdens the heart more than bilateral PA, providing a possible explanation for the higher incidence of cardiac complications in unilateral disease. A similar reduction in aldosterone-induced volume excess was obtained with targeted surgical and medical treatment of PA.

Indirect Markers of Intestinal Damage in IgA Nephropathy.

INTRODUCTION: Presence of subclinical intestinal inflammation has repeatedly been shown in IgA nephropathy (IgAN) and the degree of histological inflammation has correlated with abnormal urinary findings. There is lack of noninvasive biomarkers evaluating the presence of subclinical intestinal damage in IgAN. We conducted this study hypothesizing that selected biomarkers regarded as indirect markers of intestinal damage could be elevated in IgAN. METHODS: Eighty-five primary IgAN patients (median age 55 years, 54% men) participated in this single-center study in Tampere, Finland. None had end-stage kidney disease or previously diagnosed enteropathies. Celiac disease was excluded with serum transglutaminase 2 antibody (TG2Ab) and endomysial antibody tests and inflammatory bowel disease with fecal calprotectin. Intestinal damage was evaluated from sera with analyses of intestinal fatty-acid binding protein (I-FABP), soluble cluster of differentiation molecule 14 (sCD14), and lipopolysaccharide binding protein. Fourteen people suffering from dyspepsia and 15 healthy people served as controls. RESULTS: I-FABP levels among IgAN patients were higher than in the healthy controls (median 830 pg/mL vs. 289 pg/mL, p < 0.001). Also, sCD14 was increased in IgAN patients compared to dyspepsia controls. Although TG2Ab levels were within the normal range among IgAN patients, they were higher than in the healthy controls (median 1.3 U/mL vs. 0.6 U/mL, p < 0.001). CONCLUSIONS: Elevated serum levels of I-FABP were present in primary IgAN patients without known enteropathies. Serum I-FABP may indicate the presence of subclinical intestinal damage. These findings encourage further investigation into the role of the intestine in the pathophysiology of IgAN.

Volume overload is a major characteristic in primary aldosteronism: a 3-year follow-up study.

OBJECTIVES: We examined haemodynamics, focusing on volume balance and forward and backward wave amplitudes, before and after 2.8 years of targeted treatment of primary aldosteronism. Patients with essential hypertension and normotensive individuals were examined for comparison ( n  = 40 in each group). METHODS: Recordings were performed using radial artery pulse wave analysis and whole-body impedance cardiography. Unilateral aldosteronism was treated with adrenalectomy ( n  = 20), bilateral aldosteronism with spironolactone-based medication ( n  = 20), and essential hypertension with standard antihypertensive agents. RESULTS: Aortic SBP and DBP, forward and backward wave amplitudes, and systemic vascular resistance were equally elevated in primary aldosteronism and essential hypertension. All these haemodynamic variables were similarly reduced by the treatments. Primary aldosteronism presented with 1 litre (∼10%) extracellular water excess ( P  < 0.001) versus the other groups, and this excess was normalized by treatment. Initial pulse wave velocity (PWV) was similarly increased in primary aldosteronism and essential hypertension, but final values remained higher in primary aldosteronism ( P  < 0.001). In regression analyses, significant explanatory factors for treatment-induced forward wave amplitude reduction were decreased systemic vascular resistance ( ß â€Š= 0.380) and reduced extracellular water volume ( ß â€Š= 0.183). Explanatory factors for backward wave amplitude reduction were changes in forward wave amplitude ( ß â€Š= 0.599), heart rate ( ß â€Š= -0.427), and PWV ( ß â€Š= 0.252). CONCLUSION: Compared with essential hypertension, the principal haemodynamic difference in primary aldosteronism was higher volume load. Volume excess elevated forward wave amplitude, which was subsequently reduced by targeted treatment of primary aldosteronism, along with normalization of volume load. We propose that incorporating extracellular water evaluation alongside routine diagnostics could enhance the identification and diagnosis of primary aldosteronism.

Clinical significance of CYP11B2 immunostaining in unilateral primary aldosteronism.

Objective: The associations between adrenal histopathology, lateralization studies, and surgical outcomes in primary aldosteronism remain poorly characterized. We examined the value of immunohistochemical analysis of CYP11B2 for evaluation of adrenalectomy outcomes after anatomical versus functional subtyping. Design: A retrospective multicenter study of 277 patients operated for primary aldosteronism who had an adrenalectomy sample available in the Finnish biobanks from 1 January 2000 to 31 December 2019. Adrenal slides from biobanks were analyzed centrally after CYP11B2 and CYP11B1 staining. Clinical data were obtained from patient registries. Histopathological diagnosis and cure after surgery were assessed as outcome measures. Results: Re-evaluation with CYP11B2 staining changed the histopathological diagnosis in 91 patients (33%). The presence of a CYP11B2-positive adenoma and the use of functional subtyping independently predicted clinical cure of primary aldosteronism. CYP11B2-positive <7 mm nodules were more frequent in patients without clinical cure, whereas CYP11B2-positive micronodules were common in all patients and had no impact on adrenalectomy outcomes. Small CYP11B2-positive nodules and micronodules were equally prevalent regardless of the subtyping method applied. Clinical cure rates were lower and CYP11B2-negative adenomas more common after adrenalectomy based on anatomical imaging than functional studies. Conclusions: Incorporating CYP11B2 staining in histopathological diagnosis enhances the prediction of surgical outcomes in primary aldosteronism. A finding of CYP11B2-positive adenoma is indicative of cure of primary aldosteronism, whereas smaller CYP11B2-positive nodules associate with poorer results at postoperative evaluation. Functional subtyping methods decrease the operations of CYP11B2-negative adenomas and are superior to anatomical imaging in identifying unilateral primary aldosteronism.

Differences in heart rate responses to upright posture are associated with variations in the high-frequency power of heart rate variability.

High resting heart rate is a cardiovascular risk factor, but limited data exist on the underlying hemodynamics and reproducibility of supine-to-upright increase in heart rate. We recorded noninvasive hemodynamics in 574 volunteers [age, 44.9 yr; body mass index (BMI), 26.4 kg/m2; 49% male] during passive head-up tilt (HUT) using whole body impedance cardiography and radial artery tonometry. Heart rate regulation was evaluated using heart rate variability (HRV) analyses. Comparisons were made between quartiles of supine-to-upright heart rate changes, in which heart rate at rest ranged 62.6-64.8 beats/min (P = 0.285). The average upright increases in heart rate in the quartiles 1-4 were 4.7, 9.9, 13.5, and 21.0 beats/min, respectively (P < 0.0001). No differences were observed in the low-frequency power of HRV, whether in the supine or upright position, or in the high-frequency power of HRV in the supine position. Upright high-frequency power of HRV was highest in quartile 1 with lowest upright heart rate and lowest in quartile 4 with highest upright heart rate. Mean systolic blood pressure before and during HUT (126 vs. 108 mmHg) and the increase in systemic vascular resistance during HUT (650 vs. 173 dyn·s/cm5/m2) were highest in quartile 1 and lowest in quartile 4. The increases in heart rate during HUT on three separate occasions several weeks apart were highly reproducible (r = 0.682) among 215 participants. To conclude, supine-to-upright increase in heart rate is a reproducible phenotype with underlying differences in the modulation of cardiac parasympathetic tone and systemic vascular resistance. As heart rate at rest influences prognosis, future research should elucidate the prognostic significance of these phenotypic differences.NEW & NOTEWORTHY Subjects with similar supine heart rates are characterized by variable increases in heart rate during upright posture. Individual heart rate increases in response to upright posture are highly reproducible as hemodynamic phenotypes and present underlying differences in the modulation of cardiac parasympathetic tone and systemic vascular resistance. These results indicate that resting heart rate obtained in the supine position alone is not an optimal means of classifying people into groups with differences in cardiovascular function.

Blood Haemoglobin Concentration Is Directly and Independently Related with Pulse Wave Velocity, a Measure of Large Artery Stiffness.

High haemoglobin level has been associated with metabolic syndrome, elevated blood pressure (BP), and increased mortality risk. In this cross-sectional study, we investigated the association of blood haemoglobin with haemodynamics in 743 subjects, using whole-body impedance cardiography and pulse wave analysis. The participants were allocated to sex-stratified haemoglobin tertiles with mean values 135, 144, and 154 g/L, respectively. The mean age was similar in all tertiles, while body mass index was higher in the highest versus the lowest haemoglobin tertile. The highest haemoglobin tertile had the highest erythrocyte and leukocyte counts, plasma C-reactive protein, uric acid, renin activity, and aldosterone. The lipid profile was less favourable and insulin sensitivity lower in the highest versus the lowest haemoglobin tertile. Aortic BP, cardiac output, and systemic vascular resistance were similar in all tertiles, while the pulse wave velocity (PWV) was higher in the highest versus the lowest haemoglobin tertile. In linear regression analysis, age (Beta 0.478), mean aortic BP (Beta 0.178), uric acid (Beta 0.150), heart rate (Beta 0.148), and aldosterone-to-renin ratio (Beta 0.123) had the strongest associations with PWV (p < 0.001 for all). Additionally, haemoglobin concentration was an explanatory factory for PWV (Beta 0.070, p = 0.028). To conclude, blood haemoglobin concentration had a small direct and independent association with a measure of large artery stiffness.

Non-suppression of renin by renal cysts in a subset of patients with primary aldosteronism-a prospective observational single center study.

BACKGROUND: Screening for primary aldosteronism is based on measuring aldosterone-to-renin ratio. Non-suppressed renin may cause false negative screening results, and such patients may miss focused, potentially curable treatment. We investigated the association between renal cysts and non-suppressed plasma renin. METHODS: Altogether, 114 consecutive patients with confirmed primary aldosteronism undergoing adrenal vein sampling were prospectively recruited between October 7, 2020 and December 30, 2021. During the procedure, plasma samples for renin analyses were collected from the right and left renal veins and the inferior vena cava. Renal cysts were identified using contrast-enhanced computed tomography. RESULTS: Renal cysts were found in 58.2% of the 114 patients. Neither screening nor renal vein renin concentrations were significantly different in patients with and without cysts, or when the kidneys with and without cysts were evaluated. However, cysts were significantly more prevalent in the "high-normal renin" group (cut point 23.0 mU/L) than in the "low to low-normal renin" group (90.9%, n = 11 vs. 56.0%, n = 102, P = .027, respectively). All patients ≤50 years of age in the "high-normal renin" group had renal cysts. Strong correlations were found between renin concentrations in the right and left renal veins (r = .984), and between renin concentration and renin activity in the inferior vena cava (r = .817). CONCLUSION: Renal cysts are found in the majority of patients with primary aldosteronism, and they may interfere with diagnostics, especially in patients aged 50 years or less. In patients with non-suppressed renin due to renal cysts, aldosterone-to-renin ratio below the diagnostic threshold does not always exclude the diagnosis of primary aldosteronism.

Ambulatory daytime blood pressure versus tonometric blood pressure measurements in the laboratory: effect of posture.

OBJECTIVE: To compare blood pressure (BP) in tonometric radial artery recordings during passive head-up tilt with ambulatory recordings and evaluate possible laboratory cutoff values for hypertension. METHODS: Laboratory BP and ambulatory BP were recorded in normotensive (n = 69), unmedicated hypertensive (n = 190), and medicated hypertensive (n = 151) subjects. RESULTS: Mean age was 50.2 years, BMI 27.7 kg/m 2 , ambulatory daytime BP 139/87 mmHg, and 276 were male (65%). As supine-to-upright changes in SBP ranged from -52 to +30 mmHg, and in DBP from -21 to +32 mmHg, the mean values of BP supine and upright measurements were compared with ambulatory BP. The mean(supine+upright) systolic laboratory BP was corresponding to ambulatory level (difference +1 mmHg), while mean(supine+upright) DBP was 4 mmHg lower ( P  < 0.05) than ambulatory value. Correlograms indicated that laboratory 136/82 mmHg corresponded to ambulatory 135/85 mmHg. When compared with ambulatory 135/85 mmHg, the sensitivity and specificity of laboratory 136/82 mmHg to define hypertension were 71.5% and 77.3% for SBP, and 71.7% and 72.8%, for DBP, respectively. The laboratory cutoff 136/82 mmHg classified 311/410 subjects similarly to ambulatory BP as normotensive or hypertensive, 68 were hypertensive only in ambulatory, while 31 were hypertensive only in laboratory measurements. CONCLUSION: BP responses to upright posture were variable. When compared with ambulatory BP, mean(supine+upright) laboratory cutoff 136/82 mmHg classified 76% of subjects similarly as normotensive or hypertensive. In the remaining 24% the discordant results may be attributed to white-coat or masked hypertension, or higher physical activity during out-of-office recordings.

Low length-for-age Z-score within 1 month after birth predicts hyperdynamic circulation at the age of 21 years in rural Malawi.

Low birth weight predisposes to the development of hypertension in middle- and high-income countries. We examined the relation of early life length-for-age score (Z-score) on cardiovascular function in young adults in Malawi, a low-income country. Capture of supine, seated, and standing brachial pulse waveforms (Mobil-O-Graph) were performed in 223 females and 152 males (mean age 21 years), and analyzed according to the length-for-age Z-score tertiles during the first month of life. Plasma LDL cholesterol in young adulthood was slightly lower in the lowest versus highest tertile. Otherwise, blood hemoglobin and plasma chemistry were similar in all tertiles. Irrespective of posture, blood pressure, forward and backward wave amplitudes, and pulse wave velocity were corresponding in all tertiles. In the three postures, the lowest tertile presented with 4.5% lower systemic vascular resistance than the highest tertile (p = 0.005), and 4.4% and 5.5% higher cardiac output than the middle and highest tertiles, respectively (p < 0.01). Left cardiac work was 6.8% and 6.9% higher in the lowest tertile than in the middle and highest tertiles, respectively (p < 0.01). To conclude, in a low-income environment, low length-for-age Z-score after birth predicted hyperdynamic circulation at 21 years of age without changes in blood pressure and metabolic variables.

The characteristics of elevated blood pressure in abdominal obesity correspond to primary hypertension: a cross-sectional study.

BACKGROUND: Obesity-related hypertension and the associated metabolic abnormalities are considered as a distinct hypertensive phenotype. Here we examined how abdominal fat content, as judged by waist:height ratio, influenced blood pressure and hemodynamic profile in normotensive subjects and never-treated hypertensive patients. METHODS: The 541 participants (20-72 years) underwent physical examination and laboratory analyses and were divided into age and sex-adjusted quartiles of waist:height ratio. Supine hemodynamics were recorded using whole-body impedance cardiography, combined with analyses of radial tonometric pulse wave form and heart rate variability. RESULTS: Mean waist:height ratios in the quartiles were 0.46, 0.51, 0.55 and 0.62. Radial and aortic blood pressure, systemic vascular resistance, pulse wave velocity, markers of glucose and lipid metabolism, leptin levels and C-reactive protein were higher in quartile 4 when compared with quartiles 1 and 2 (p < 0.05 for all). Cardiac index was lower in quartile 4 versus quartile 1, while no differences were seen in heart rate variability, augmentation index, plasma renin activity, and aldosterone concentration between the quartiles. Linear regression analyses showed independent associations of abdominal obesity with higher aortic systolic and diastolic blood pressure, systemic vascular resistance, and pulse wave velocity (p < 0.05 for waist:height ratio in all regression models). CONCLUSION: Higher waist:height ratio was associated with elevated blood pressure, systemic vascular resistance, and arterial stiffness, but not with alterations in cardiac sympathovagal modulation or activation of the circulating renin-angiotensin-aldosterone system. Although obesity-related elevation of blood pressure has distinct phenotypic features, these results suggest that its main characteristics correspond those of primary hypertension. TRIAL REGISTRATION: ClinicalTrails.gov NCT01742702 (date of registration 5th December 2012).

Puumala Hantavirus Infections Show Extensive Variation in Clinical Outcome.

The clinical outcome of Puumala hantavirus (PUUV) infection shows extensive variation, ranging from inapparent subclinical infection (70-80%) to severe hemorrhagic fever with renal syndrome (HFRS), with about 0.1% of cases being fatal. Most hospitalized patients experience acute kidney injury (AKI), histologically known as acute hemorrhagic tubulointerstitial nephritis. Why this variation? There is no evidence that there would be more virulent and less virulent variants infecting humans, although this has not been extensively studied. Individuals with the human leukocyte antigen (HLA) alleles B*08 and DRB1*0301 are likely to have a severe form of the PUUV infection, and those with B*27 are likely to have a benign clinical course. Other genetic factors, related to the tumor necrosis factor (TNF) gene and the C4A component of the complement system, may be involved. Various autoimmune phenomena and Epstein-Barr virus infection are associated with PUUV infection, but hantavirus-neutralizing antibodies are not associated with lower disease severity in PUUV HFRS. Wide individual differences occur in ocular and central nervous system (CNS) manifestations and in the long-term consequences of nephropathia epidemica (NE). Numerous biomarkers have been detected, and some are clinically used to assess and predict the severity of PUUV infection. A new addition is the plasma glucose concentration associated with the severity of both capillary leakage, thrombocytopenia, inflammation, and AKI in PUUV infection. Our question, "Why this variation?" remains largely unanswered.

Urine sodium excretion is related to extracellular water volume but not to blood pressure in 510 normotensive and never-treated hypertensive subjects.

PURPOSE: High sodium intake is an accepted risk factor for hypertension, while low Na+ intake has also been associated with increased risk of cardiovascular events. In this cross-sectional study, we examined the association of 24-h urinary Na+ excretion with haemodynamics and volume status. MATERIALS AND METHODS: Haemodynamics were recorded in 510 normotensive and never-treated hypertensive subjects using whole-body impedance cardiography and tonometric radial artery pulse wave analysis. The results were examined in sex-specific tertiles of 24-h Na+ excretion, and comparisons between normotensive and hypertensive participants were also performed. Regression analysis was used to investigate factors associated with volume status. The findings were additionally compared to 28 patients with primary aldosteronism. RESULTS: The mean values of 24-h urinary Na+ excretion in tertiles of the 510 participants were 94, 148 and 218 mmol, respectively. Average tertile age (43.4-44.7 years), office blood pressure and pulse wave velocity were corresponding in the tertiles. Plasma electrolytes, lipids, vitamin D metabolites, parathyroid hormone, renin activity, aldosterone, creatinine and insulin sensitivity did not differ in the tertiles. In supine laboratory recordings, there were no differences in aortic systolic and diastolic blood pressure, heart rate, cardiac output and systemic vascular resistance. Extracellular water volume was higher in the highest versus lowest tertile of Na+ excretion. In regression analysis, body surface area and 24-h Na+ excretion were independent explanatory variables for extracellular water volume. No differences in urine Na+ excretion and extracellular water volume were found between normotensive and hypertensive participants. When compared with the 510 participants, patients with primary aldosteronism had 6.0% excess in extracellular water (p = .003), and 24-h Na+ excretion was not related with extracellular water volume. CONCLUSION: In the absence of mineralocorticoid excess, Na+ intake, as evaluated from 24-h Na+ excretion, predominantly influences extracellular water volume without a clear effect on blood pressure.

We evaluated sodium intake in 510 subjects by measuring their 24-h sodium excretion to the urine and examined whether sodium intake was related with alterations in cardiovascular function and fluid balance. All participants were without blood pressure lowering medications.Blood pressure was recorded by a device that senses the radial artery pulsations form the wrist. The amount of blood pumped by the heart, the transfer of pressure waves following cardiac contractions and body fluid status were evaluated using bioimpedance, a method recording changes in body electrical resistance.For the analyses, the participants were divided into tertiles according to their 24-h sodium excretions. We also compared results between normotensive and hypertensive subjects.The 24-h sodium excretion in the tertiles corresponded to about 6 g, 9 g and 13 g of salt intake per day, respectively. There were no differences between the tertiles in age, routine laboratory analyses, blood pressure, large arterial stiffness, amount blood pumped by the heart and resistance to blood flow in the arteries. However, there was more extracellular fluid in the highest versus the lowest tertile of sodium excretion. Further statistics indicated that extracellular fluid volume in the body was mainly determined by body size, but it was also moderately influenced by sodium intake.No differences in 24-h sodium excretion and extracellular water volume were found between normotensive and hypertensive participants.In subjects not using blood pressure lowering medications, sodium intake predominantly influences the amount of extracellular fluid without a clear effect on blood pressure.

Moderate hyperuricaemia ameliorated kidney damage in a low-renin model of experimental renal insufficiency.

Uric acid has promoted renal fibrosis and inflammation in experimental studies, but some studies have shown nephroprotective effects due to alleviated oxidative stress. We studied the influence of experimental hyperuricaemia in surgically 5/6 nephrectomized rats. Three weeks after subtotal nephrectomy or sham operation, the rats were allocated to control diet or 2.0% oxonic acid (uricase inhibitor) diet for 9 weeks. Then blood, urine and tissue samples were taken, and renal morphology and oxidative stress were examined. Inflammation and fibrosis were evaluated using immunohistochemistry and real-time PCR (RT-PCR). Remnant kidney rats ingesting normal or oxonic acid diet presented with ~60% reduction of creatinine clearance and suppressed plasma renin activity. Oxonic acid diet increased plasma uric acid levels by >80 µmol/L. In remnant kidney rats, moderate hyperuricaemia decreased glomerulosclerosis, tubulointerstitial damage and kidney mast cell count, without influencing the fibrosis marker collagen I messenger RNA (mRNA) content. In both sham-operated and 5/6 nephrectomized rats, the mast cell product 11-epi-prostaglandin-F2α excretion to the urine and kidney tissue cyclooxygenase-2 (COX-2) levels were decreased. To conclude, hyperuricaemic remnant kidney rats displayed improved kidney morphology and reduced markers of oxidative stress and inflammation. Thus, moderately elevated plasma uric acid had beneficial effects on the kidney in this low-renin model of experimental renal insufficiency.

Presence of gastrointestinal symptoms in IgA nephropathy: a cross-sectional study.

BACKGROUND: Gastrointestinal (GI) symptoms are common in end-stage kidney disease. Mounting evidence indicates that the intestine plays an important role in the pathogenesis of IgA nephropathy (IgAN). However, no studies have addressed the obvious question; do IgAN patients suffer from GI symptoms? METHODS: Presence of GI symptoms and health-related quality of life were evaluated using the validated Gastrointestinal Symptom Rating Scale (GSRS) and Psychological General Well-Being (PGWB) questionnaires in 104 patients with kidney biopsy-verified IgAN and in 147 healthy controls. A person was regarded to experience 'increased GI symptoms' if the GSRS score exceeded plus 1 standard deviation of the mean of the corresponding score in the healthy controls. RESULTS: According to the GSRS total score, the IgAN patients had more GI symptoms than the healthy controls (2.0 vs. 1.7, p < 0.001). Female IgAN patients had higher GSRS total score than male patients (2.2 vs. 1.7, p = 0.001). More IgAN patients with preserved kidney function (eGFR > 60ml/min/1.73m2) suffered from increased symptoms of diarrhoea (76 vs. 25%, p = 0.028), constipation (81 vs. 19%, p = 0.046) and reflux (85 vs. 15%, p = 0.004) than did IgAN patients with reduced kidney function (eGFR < 60ml/min/1.73m2). CONCLUSIONS: IgAN patients and especially female IgAN patients experienced more GI symptoms than healthy controls. More prevalent GI symptoms were already observed before kidney function was clearly reduced. Systematic enquiry of GI symptoms might increase the standard of care among IgAN patients. Moreover, GI symptoms may provide clues for future studies that examine the pathophysiology of IgAN.

Lateralization in 11 C-Metomidate PET and outcome of adrenalectomy in primary aldosteronism.

INTRODUCTION: Subtype classification method is essential when considering adrenalectomy as a possible treatment for primary aldosteronism. We aimed to retrospectively evaluate surgical outcomes of primary aldosteronism in patients who had undergone 11 C-metomidate positron emission tomography (11 C-MTO-PET) for subtype classification. METHODS: Postoperative clinical and biochemical cure and histopathological diagnosis from biobank samples were retrospectively evaluated in 44 patients who had all undergone preoperative 11 C-MTO-PET with or without adrenal venous sampling (AVS). We compared those operated based on 11 C-MTO-PET alone and those with concordant or discordant lateralization in 11 C-MTO-PET and AVS studies according to postoperative immunohistochemical findings and biochemical and clinical cure. RESULTS: Adrenalectomy side was based on 11 C-MTO-PET alone in 14 cases and on AVS in 30 cases of whom 42 achieved complete and two partial biochemical cures. Among those who underwent AVS and were operated according to it, the two lateralization methods were concordant in 22 cases and discordant in 8 cases. Similar immunohistochemical profiles and cure rates were seen after 11 C-MTO-PET alone or AVS-based operations. Respectively, those with concordant or discordant 11 C-MTO-PET and AVS lateralization did not differ in surgical outcome. Together, we found errors of lateralization diagnostics with 11 C-MTO-PET in 18% and with AVS in 3% among those eligible for adrenal surgery. CONCLUSIONS: Outcomes of adrenalectomy based on clinically significant lateralization in 11 C-MTO-PET alone correspond to those based on 11 C-MTO-PET with concordant AVS lateralization. However, our results suggest that diagnosis of unilateral PA should be performed with caution with 11 C-MTO-PET in case of discordant lateralization studies.

Resting heart rate predicts cardiac autonomic modulation during passive head-up tilt in subjects without cardiovascular diseases.

Background Resting heart rate (HR) and its variability (HRV) reflects the cardiac sympathovagal balance that is stimulated by head-up tilting. HRV is influenced by the level of HR, but how much HRV offers additional information about cardiac autonomic tone than HR alone remains unresolved. We examined the relation of resting HR with HRV during head-up tilt. Methods. Hemodynamics of 569 subjects without known cardiovascular diseases and medications with direct cardiovascular effects were recorded using whole-body impedance cardiography, radial pulse wave analysis, and electrocardiography-based HRV analysis during passive head-up tilt. Results. Higher low frequency to the high-frequency ratio (LF/HF) of HRV (reflecting sympathovagal balance) was associated with higher HR in supine (p < .05, both linear regression analysis and variance analysis comparing HR tertiles) and upright postures (p < .001, linear regression analysis). The association of HR with HRV during tilt-testing remained significant when the HR dependence of HRV was mathematically weakened by dividing the HRV power spectra with the fourth power of the average RR-interval. Conclusion. Higher resting HR is related to higher LF/HF both supine and upright, reflecting elevated sympathetic influence on cardiac autonomic modulation. Lower resting HR is associated with lower resting LF/HF, while the differences in LF/HF between the HR tertiles were minor during head-up tilt, suggesting a greater change in cardiac sympathovagal balance in response to upright posture in those with lowest resting HR. Altogether, resting HR well predicts HRV levels during head-up tilt.Trial registration: Clinicaltrialsregister.eu 2006-002065-39, first registered 5 May 2006. ClinicalTrials.gov NCT01742702, first registered 5 December 2012.

Various vascular malformations are prevalent in Finnish pseudoxanthoma elasticum (PXE) patients: a national registry study.

BACKGROUND: Pseudoxanthoma elasticum (PXE, OMIM# 264800) is an inborn error of metabolism causing ectopic soft tissue calcification due to low plasma pyrophosphate concentration. We aimed to assess the prevalence of PXE in Finland and to characterize the Finnish PXE population. A nationwide registry search was performed to identify patients with ICD-10 code Q82.84. Information was gathered from available medical records which were requisitioned from hospitals and health centers. Misdiagnosed patients and patients with insufficient records were excluded. RESULTS: The prevalence of PXE in Finland was 1:260,000 with equal sex distribution. Patients with high conventional cardiovascular risk had more visual and vascular complications than patients with low risk. Four patients (19%) had at least one vascular malformation. A high proportion (33%) of ABCC6 genotypes were of the common homozygous c.3421C > T, p.Arg1141Ter variant. Nine other homozygous or compound heterozygous allelic variants were found. CONCLUSIONS: The prevalence of diagnosed PXE appears to be lower in Finland than in estimates from other countries. Decreased visual acuity is the most prevalent complication. We suggest that various vascular malformations may be an unrecognized feature of PXE.

Alcohol Consumption and Its Influence on the Clinical Picture of Puumala Hantavirus Infection.

Puumala hantavirus (PUUV) causes hemorrhagic fever with renal syndrome. Characteristic clinical findings include acute kidney injury (AKI), thrombocytopenia, and capillary leakage. Smoking increases the risk of severe AKI, but it is not known whether alcohol consumption predisposes patients to a more severe infection. Liver and pancreatic enzymes, as well as biomarkers of alcohol consumption (gamma-glutamyl transferase, GGT; carbohydrate-deficient transferrin, CDT; GGT-CDT combination; and ethyl glucuronide, EtG), were measured from 66 patients with acute PUUV infection during hospitalization and at the convalescence phase. Alcohol consumption was present in 41% of the study population, 15% showing signs of heavy drinking. Alcohol use did not affect the severity of PUUV induced AKI nor the overall clinical picture of the infection. Liver enzyme levels (GGT or alanine aminotransferase, ALT) were elevated in 64% of the patients, but the levels did not associate with the markers reflecting the severity of the disease. Serum amylase activities at the convalescent stage were higher than those at the acute phase (p < 0.001). No cases with acute pancreatitis were found. In conclusion, our findings indicate that alcohol consumption does not seem to affect the clinical course of an acute PUUV infection.