Effect of urine pH changed by dietary intervention on uric acid clearance mechanism of pH-dependent excretion of urinary uric acid

Higher dietary acid load is associated with the risk of hyperuricemia

PURPOSE

Dietary acid load plays a key role in regulating serum uric acid levels. We hypothesized that dietary acid load indices would be positively associated with the odds of hyperuricemia. We aimed to test this hypothesis in a representative sample of Iranian adult population.

METHODS

In this cross-sectional study, a total of 6145 participants aged 35-65 years were recruited from MASHAD cohort study. Dietary intakes were assessed using a 24-h dietary recall. Diet-based acid load was assessed as the potential renal acid load (PRAL), net endogenous acid production (NEAP), and dietary acid load (DAL). Hyperuricemia was defined as serum uric acid greater than the 75th percentile. Multivariable logistic regression models were applied to determine the association between diet-based acid load scores and hyperuricemia.

RESULTS

The mean age of participants was 48.89 ± 8.09 years. Overall, 25.7% had hyperuricemia. According to the full-adjusted model, there was a significant association between higher tertile of PRAL, and DAL and hyperuricemia (Q3 PRAL; OR (95% CI): 1.23 (1.05-1.43), Q3 DAL; OR (95% CI): 1.22 (1.05-1.42)). Regarding NEAP, there was no significant association with hyperuricemia. We also found that dietary intake of total sugars, fiber, calcium, and magnesium was associated with the odds of hyperuricemia in our population.

CONCLUSION

This study showed a significant positive association between two indicators of dietary acid load (PRAL, and DAL) and odds of hyperuricemia among Iranian adults.

The Rise in Tubular pH during Hypercalciuria Exacerbates Calcium Stone Formation

In calcium nephrolithiasis (CaNL), most calcium kidney stones are identified as calcium oxalate (CaOx) with variable amounts of calcium phosphate (CaP), where CaP is found as the core component. The nucleation of CaP could be the first step of CaP+CaOx (mixed) stone formation. High urinary supersaturation of CaP due to hypercalciuria and an elevated urine pH have been described as the two main factors in the nucleation of CaP crystals. Our previous in vivo findings (in mice) show that transient receptor potential canonical type 3 (TRPC3)-mediated Ca2+ entry triggers a transepithelial Ca2+ flux to regulate proximal tubular (PT) luminal [Ca2+], and TRPC3-knockout (KO; -/-) mice exhibited moderate hypercalciuria and microcrystal formation at the loop of Henle (LOH). Therefore, we utilized TRPC3 KO mice and exposed them to both hypercalciuric [2% calcium gluconate (CaG) treatment] and alkalineuric conditions [0.08% acetazolamide (ACZ) treatment] to generate a CaNL phenotype. Our results revealed a significant CaP and mixed crystal formation in those treated KO mice (KOT) compared to their WT counterparts (WTT). Importantly, prolonged exposure to CaG and ACZ resulted in a further increase in crystal size for both treated groups (WTT and KOT), but the KOT mice crystal sizes were markedly larger. Moreover, kidney tissue sections of the KOT mice displayed a greater CaP and mixed microcrystal formation than the kidney sections of the WTT group, specifically in the outer and inner medullary and calyceal region; thus, a higher degree of calcifications and mixed calcium lithiasis in the kidneys of the KOT group was displayed. In our effort to find the Ca2+ signaling pathophysiology of PT cells, we found that PT cells from both treated groups (WTT and KOT) elicited a larger Ca2+ entry compared to the WT counterparts because of significant inhibition by the store-operated Ca2+ entry (SOCE) inhibitor, Pyr6. In the presence of both SOCE (Pyr6) and ROCE (receptor-operated Ca2+ entry) inhibitors (Pyr10), Ca2+ entry by WTT cells was moderately inhibited, suggesting that the Ca2+ and pH levels exerted sensitivity changes in response to ROCE and SOCE. An assessment of the gene expression profiles in the PT cells of WTT and KOT mice revealed a safeguarding effect of TRPC3 against detrimental processes (calcification, fibrosis, inflammation, and apoptosis) in the presence of higher pH and hypercalciuric conditions in mice. Together, these findings show that compromise in both the ROCE and SOCE mechanisms in the absence of TRPC3 under hypercalciuric plus higher tubular pH conditions results in higher CaP and mixed crystal formation and that TRPC3 is protective against those adverse effects.

Association of Urine (pH < 5.5) with Community Periodontal Index (CPI) and the Number of Remaining Teeth in Korean Adults: A Cross-Sectional Study Using Data from Korea National Health and Nutrition Examination Survey 2016-2018

This study aims to determine the association between UpH (<5.5), Community Periodontal Index (CPI), and the number of remaining teeth-cumulative indicators of oral health-using data from the 7th Korea National Health and Nutrition Examination Survey (KNHANES, 2016-2018), which represents the Korean population. Data from 12,689 adults aged 19 years and older who had periodontal examinations were analyzed. Logistic regression analysis was performed after adjusting for demographic, health, and health-related behavioral factors as covariates to determine the association between UpH, CPI, and the number of remaining teeth. This study found that UpH (<5.5) was associated with CPI and the number of remaining teeth. For UpH (<5.5), the odds ratio for CPI (≥4 mm) was 1.19 times (95% CI: 1.06-1.33). The risk of tooth loss was 1.25 times (95% CI: 1.06-1.48) for those with 0-19 remaining teeth and 1.20 times (95% CI: 1.07-1.34) for those with 20-27 teeth. The results revealed an association between UpH, CPI, and the number of remaining teeth. However, further longitudinal research on UpH and oral status is necessary.

Next-Generation Femtech: Urine-Based Cervical Cancer Diagnosis Using a Fluorescent Biothiol Probe with Controlled Smiles Rearrangement

Cervical cancer screening is a crucial field of femtech (female technology). In this work, we disclosed a new femtech solution─a simple, straightforward, and on-site applicable urine-based cervical cancer diagnostic method using a fluorescent biothiol probe. Our newly developed nitrobenzene-based fluorescent probe, named NPS-B, effectively differentiates between cysteine and homocysteine within urine samples via controlled Smiles rearrangement. The analysis of emission-based signals offers the potential utility of this method in cervical cancer. NPS-B was designed by considering the substitution effect and structural polarity of the nitrobenzene-based fluorophore. This controlled modification of nitrobenzene-induced substantial intramolecular charge transfer changes in the fluorophore when exposed to biothiols, resulting in significant changes in photophysical properties. NPS-B displayed different emissions of cysteine and homocysteine in clinical human urine (without prior urine treatment). Overall, our findings provide insights not only into fundamental chemical science but also into the broader domain of applied sciences.

Association between vegetarian diet and gouty arthritis: A retrospective cohort study

BACKGROUND AND AIMS

A vegetarian diet is rich in vegetables, fruits, and soy products. Although vegetarian diet is beneficial for improving the health outcomes such as body mass index, metabolic syndrome, cardiovascular disease, and mortality rate, the association between a vegetarian diet and gout incidence is not well known.

METHODS AND RESULTS

We linked the MJ Health Survey Data and MJ Biodata 2000 with the National Health Insurance Research Database (NHIRD) and the National Registration of Death (2000-2018). Information on the diet was collected from the MJ Health Survey Data, and the incidence of gouty arthritis was confirmed using the NHIRD. The Kaplan-Meier survival curve and log-rank test were used to compare the differences between vegetarian and non-vegetarian participants. Cox regression models were used to estimate the risk of the incidence of gouty arthritis. Among 76,972 participants, 37,297 (48.46%) were men, 2488 (3.23%) were vegetarians and the mean age was 41.65 ± 14.13 years. The mean baseline uric acid level was 6.14 ± 1.65 mg/dL. A total of 16,897 participants developed gouty arthritis, including 16,447 (22.08%) non-vegetarians and 450 (18.9%) vegetarians over a mean follow-up of 19 years. Significant differences were observed in the Kaplan-Meier survival curves between vegetarians and non-vegetarians (log-rank p < 0.001). Vegetarians had a significantly decreased incidence of gouty arthritis compared with non-vegetarians (hazard ratio = 0.87, 95% confidence interval = 0.78-0.98, p = 0.02) after adjusting for potential confounders.

CONCLUSION

People with a vegetarian diet had a significantly decreased risk of developing gouty arthritis compared with non-vegetarians in Taiwan.

The pH of Drinking Water and Its Effect on the pH of Urine

AIM

The aim was to determine whether urine pH changed or not with different pH values of drinking water. With the results obtained from animal studies, comments can be made about the effect of water with different pH levels that people drink on kidney stones.

METHOD

A total of 24 Wistar Albino rats were divided into three groups containing eight rats each: the first group was given water with pH 5.5, the second group was given water with pH 7 and the third group was given water with pH 8.2 in the same environment and conditions during 13 days. All rats consumed water in line with their natural feeding habits. All rats had urine pH measurements performed and recorded every day at the same time. The groups were later compared in terms of daily pH values.

RESULTS

When daily urine pH values were compared, there were statistically significant differences between pH measurements on the first, fourth and seventh day (p=0.02, p=0.017 and p=0.007, respectively). When first-day values are compared with post-hoc analyses, the urine pH in Group 2 was identified to be lower compared to Group 1 and Group 3 (p<0.001). When the fourth-day values were assessed, the urine pH of Group 2 was observed to be higher than Group 1 and Group 3 (p<0.001). On the seventh day, Group 3 had higher urine pH compared to the other groups (p<0.001).

CONCLUSION

The variation in drinking water pH does not directly change urine pH; however, it causes a change in the urine pH on different days.

Renal Disturbances during and after Radioligand Therapy of Neuroendocrine Tumors-Extended Analysis of Potential Acute and Chronic Complications

Neuroendocrine tumors (NEN) are a group of neoplasms that arise from hormonal and neural cells. Despite a common origin, their clinical symptoms and outcomes are varied. They are most commonly localized in the gastrointestinal tract. Targeted radioligand therapy (RLT) is a treatment option which has proven to be successful in recent studies. However, the possible outcomes and true safety profile of the treatment need to be fully determined, especially by new, more sensitive methods. Our study aimed to present an extended analysis of acute and chronic renal complications during and after radioligand therapy using, for the first time in the literature, innovative and complex renal parameters. Forty patients with neuroendocrine tumors underwent four courses of radioligand therapy with [¹⁷⁷Lu]Lu-DOTATATE or [¹⁷⁷Lu]Lu/[⁹⁰Y]Y-DOTATATE. Radioisotopes were administrated in intervals of 8-12 weeks, with concurrent intravenous nephroprotection. New detailed and sensitive renal parameters were used to determine the renal safety profile during and after radioisotope therapy for standard treatment of NEN. During the first and fourth courses of RLT, no change in the glomerular filtration rate (GFR) was observed. However, long-term observations one year after the treatment showed a 10% reduction in the GFR. During the first course of treatment, the fractional urea and calcium excretions increased, while the fractional potassium concentration decreased. The fractional calcium excretion remained highly increased in long-term observations. Decreases in urine IL-18, KIM-1 and albumin concentrations were observed during RLT. The concentrations of IL-18 and KIM-1 remained low even a year after therapy. The ultrasound parameters of renal perfusion changed during treatment, before partially returning to the baseline one year after therapy, and were correlated with the biochemical parameters of renal function. A permanent increase in diastolic blood pressure was correlated with the decrease in the GFR observed during the study. In this innovative and complex renal assessment during and after RLT, we found a permanent 10% per year decrease in the GFR and noticeable disturbances in renal tubule function. The diastolic blood pressure also increased.

Association between Dietary Acid Load and Hyperuricemia in Chinese Adults: Analysis of the China Health and Nutrition Survey (2009)

BACKGROUND

This study evaluates the association between dietary acid load (DAL) and hyperuricemia in Chinese adults.

METHODS

The China Health and Nutrition Survey (CHNS) in 2009 was used in this cross-sectional study. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were applied to estimate DAL. A multiple logistic regression model was used to test the relationship between DAL and hyperuricemia risk.

RESULTS

A total of 7947 participants were included in this study, of whom 1172 had hyperuricemia. The PRAL score was positively related to the prevalence of hyperuricemia, even when potential covariates were taken into account. In comparison with Q1, the ORs were 1.12 (95% CI, 0.92-1.38), 1.20 (95% CI, 0.97-1.47) and 1.42 (95% CI, 1.16-1.75) in Q2, Q3 and Q4. However, there was no significant relationship between NEAP scores and hyperuricemia. Every 10 g increase in energy-adjusted fat, protein and animal protein intakes caused a 10%, 17% and 18% increase in hyperuricemia risk, respectively (OR: 1.10, 95% CI: 1.04-1.16; OR: 1.17, 95% CI: 1.11-1.25; OR: 1.18, 95% CI: 1.12-1.24, respectively). An obvious linear correlation was also suggested by the restricted cubic spline.

CONCLUSIONS

Hyperuricemia risk was associated with higher PRAL among Chinese adults. This means that a diet low in PRAL scores could be a very valuable uric acid-lowering dietary pattern.

The Association between Water Consumption and Hyperuricemia and Its Relation with Early Arterial Aging in Middle-Aged Lithuanian Metabolic Patients

BACKGROUND

Hyperuricemia is well-known as an independent risk factor for the development of hypertension, metabolic syndrome, and cardiovascular disease. Water is essential to most bodily functions, and its consumption rates appear to decline with age. The aim was to evaluate the influence of water intake on early vascular aging in metabolic middle-aged patients with hyperuricemia.

MATERIALS AND METHODS

The study included 241 men aged 40-55 years and 420 women aged 50-65 years from the Lithuanian High Cardiovascular Risk (LitHiR) primary prevention program. Anthropometric characteristics, blood pressure, laboratory testing, and the specialized nutrition profile questionnaire were evaluated. Carotid-femoral pulse wave velocity (cfPWV), assessed using applanation tonometry, was evaluated as an early vascular aging parameter in patients with hyperuricemia and with normal serum uric acid (sUA) levels.

RESULTS

72.6% of men and 83.1% of women drink insufficient amounts of water (less than 1.5 L per day). However, our results showed statistically significant relationships only among a group of women. The women in the hyperuricemic group had a higher cfPWV than women with normal sUA levels. In hyperuricemic women, drinking less than 0.5 L per day in combination with other risk factors, such as age, increasing fasting glucose, and systolic blood pressure, was statistically significantly associated with an increased cfPWV (R² = 0.45, Adj. R² = 0.42, p < 0.001).

CONCLUSION

Drinking an insufficient amount of water daily is associated with increased arterial stiffness and has a negative effect on vascular health in metabolic women with hyperuricemia.

Comparison potassium sodium hydrogen citrate with sodium bicarbonate in urine alkalization: a prospective crossover-controlled trial

PURPOSE

Excessive alkalization will increase the incidence of nephrolithiasis. Sodium bicarbonate (NaHCO₃) and potassium sodium hydrogen citrate (PSHC) are commonly used drugs for urinary alkalization. We designed a trial to compare PSHC with NaHCO₃ in the urine alkalization for the Chinese healthy participants and to explore the effects of PSHC and NaHCO₃ on circadian rhythms of urine pH value.

METHOD

This study was a prospective, crossover, randomized, controlled trial, in which a total of 34 healthy volunteers participated in two study phases and took PSHC and NaHCO₃ at the maintenance dose, respectively.

RESULT

The average level of urine pH of PSHC participants in 24 h was significantly higher than that of NaHCO₃ (P < 0.001). The urine pH value of participants taking PSHC and NaHCO₃ or under physiological conditions showed significant variation in 24 h (P < 0.05) and fitted to a mathematical model (Fourier series). Under physiological conditions, the average urine pH value in the daytime was higher than that in the night, and reached the peak at about 10:00, 16:00, and 22:00. The peak of urine pH at 24 h after taking PSHC and NaHCO₃ was both higher than the baseline. The peak time of urine pH and the curve trend were similar, but the peak value in PSHC group was significantly higher than that in NaHCO₃ group.

CONCLUSIONS

There was a circadian rhythm of urine pH value under physiological conditions. PSHC was more effective in urinary alkalization than NaHCO₃ at the current maintenance oral dose and administration time without changing the rhythm of urine pH value.

CLINICAL TRIAL REGISTRATION

NCT04352153.

Chronic Sub-Clinical Systemic Metabolic Acidosis - A Review with Implications for Clinical Practice

When arterial serum pH remains near the lower pH limit of 7.35 for protracted periods of time, a low-grade, sub-clinical form of acidosis results, referred to in this review as chronic, sub-clinical, systemic metabolic acidosis (CSSMA). This narrative review explores the scientific basis for CSSMA, its consequences for health, and potential therapeutic interventions. The major etiology of CSSMA is the shift away from the ancestral, alkaline diet which was rich in fruit and vegetables, toward the contemporary, acidogenic 'Westernized' diet characterized by higher animal protein consumption and lack of base forming minerals. Urine pH is reduced with high dietary acid load and may be a convenient marker of CSSMA. Evidence suggests further that CSSMA negatively influences cortisol levels potentially contributing significantly to the pathophysiology thereof. Both CSSMA and high dietary acid load are associated with the risk and prognosis of various chronic diseases. Clinical trials show that CSSMA can be addressed successfully through alkalizing the diet by increasing fruit and vegetable intake and/or supplementing with alkaline minerals. This review confirms the existence of a significant body of evidence regarding this low-grade form of acidosis as well as evidence to support its diverse negative implications for health, and concludes that CSSMA is a condition warranting further research.

Differences of Uric Acid Transporters Carrying Extracellular Vesicles in the Urine from Uric Acid and Calcium Stone Formers and Non-Stone Formers

Background: Low urine pH and volume are established risk factors for uric acid (UA) stone disease (UASD). Renal tubular epithelial cells exposed to an acidic pH and/or UA crystals can shed extracellular vesicles (EVs) into the tubular fluid, and these EVs may be a pathogenic biomarker of UASD. Methods: Urinary EVs bearing UA transporters (SLC2A9, SLC17A3, SLC22A12, SLC5A8, ABCG2, and ZNF365) were quantified in urine from UA stone formers (UASFs), calcium stone formers (CSFs), and age-/sex-matched non-stone formers (NSFs) using a standardized and published method of digital flow cytometry. Results: Urinary pH was lower (p < 0.05) and serum and urinary UA were greater (p < 0.05) in UASFs compared with NSFs. Urinary EVs carrying SLC17A3 and SLC5A8 were lower (p < 0.05) in UASFs compared with NSFs. Urinary EVs bearing SLC2A9, SLC22A12, SLC5A8, ABCG2, and ZNF365 were lower (p < 0.05) in CSFs than UASFs, while excretion of SLC17A3-bearing EVs did not differ between groups. Conclusion: EVs bearing specific UA transporters might contribute to the pathogenesis of UASD and represent non-invasive pathogenic biomarkers for calcium and UA stone risk.

RUMA and RUPCR in children with Henoch–Schonlein purpura

Objective

The aim of this study was to compare the qualitative and quantitative targets in the detection of proteinuria in children with HSP.

Methods

Three hundred and forty children were taken as the research subjects. Qualitative and a series of quantitative indicators of urine protein were tested.

Results

The qualitative and quantitative of protein in 340 children were analyzed retrospectively. Correlation analysis found that 24hUTP had a strong correlation with age, RUMA, RUPCR, and qualitative urine occult blood (p < 0.01, for all). After regression analysis, RUMA and RUPCR were still significantly correlated with 24hUTP (p < 0.01). At the same time, RUMA and RUPCR had good diagnostic accuracy for proteinuria. When the RUPCR ratio was set as 0.415, the diagnostic sensitivity was 83%, and the specificity was 98.7%. When RUMA was set as 68.215, the sensitivity was 94.3% and the specificity was 96.2%.

Conclusion

Compared with 24hUTP, RUMA and RUPCR had high sensitivity and specificity for monitoring proteinuria in children with HSP.

Association of acidic urine pH with impaired renal function in primary gout patients: a Chinese population-based cross-sectional study

Background

Patients with gout frequently have low urinary pH, which is associated with the nephrolithiasis. However, the specific distribution of urinary pH and potential relationship of acidic urine pH to broader manifestations of kidney disease in gout are still poorly understood.

Methods

A 2016–2020 population-based cross-sectional study was conducted among 3565 gout patients in the dedicated gout clinic of the Affiliated Hospital of Qingdao University to investigate the association between low urinary pH and kidney disease. We studied patients that we defined to have “primary gout”, based on the absence of > stage 2 CKD. All subjects underwent 14 days of medication washout and 3-day standardized metabolic diet. We obtained general medical information, blood and urine biochemistries, and renal ultrasound examination on the day of the visit. The primary readouts were urine pH, eGFR, nephrolithiasis, renal cysts, microhematuria, and proteinuria. Patients were assigned into 5 subgroups (urine pH ≤5.0, 5.0 <pH≤ 5.5, 5.5 <pH< 6.2, 6.2 ≤pH≤ 6.9, and pH >6.9), aligning with the clinical significance of urine pH.

Results

Overall, the median urine pH and eGFR of all patients was 5.63 (IQR 5.37~6.09), and 98.32 (IQR 86.03~110.6), with acidic urine in 46.5% of patients. The prevalence of nephrolithiasis, microhematuria, and proteinuria were 16.9%, 49.5%, and 6.9%, respectively. By univariate analysis, eGFR was significantly associated with age, sex, duration of gout, tophus, body mass index, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, serum utare, hypertension, diabetes, and urine pH. On multivariable analysis, eGFR was associated with age, sex, diastolic blood pressure, serum uric acid, hypertension, diabetes, and urine pH. Acidic urine pH, especially urine pH < 5.0, was significantly associated with the prevalence of kidney disease, including > stage 1 CKD, nephrolithiasis, kidney cyst, and microhematuria. Patients with 6.2 ≤ urine pH ≤ 6.9 and SU ≤ 480 μmol/L had the highest eGFR with the lowest prevalence of nephrolithiasis, microhematuria, and proteinuria.

Conclusions

Approximately half of gout subjects had acidic urine pH. Urine pH < 5.0 was associated with significantly increased nephrolithiasis, renal cyst, microhematuria, and proteinuria. The results support prospective clinical investigation of urinary alkalinization in selected gout patients with acidic urine pH.

Hyperuricemia: Features of the Diet

The association of hyperuricemia (HU) with cardiovascular disease (CVD), diabetes, metabolic syndrome, and kidney disease has been demonstrated in numerous studies. НU is the main pathogenetic factor in the development of gout and is associated with an increase in overall and cardiovascular mortality. НU is included in the list of factors determining cardiovascular risk. According to epidemiological studies, there is a high prevalence of HU in the world and its increase in recent decades. A number of factors have been identified that contribute to the increased risk of НU. Non-modifiable factors include gender, age, genetic factors, and modifiable factors include diet and lifestyle. Nutritional unbalances, increased life expectancy, increased prevalence of obesity, and increased use of drugs (especially diuretics) are seen as contributing factors to the rise in НU. The review was carried out to summarize the available information on the effect of dietary habits, individual foods and nutrients on serum uric acid (SUA) levels and the risk of developing HU. The review presents the results of scientific studies demonstrating the relationship of НU with the consumption of foods rich in purines (offal, red meat, fish, seafood, legumes), alcohol consumption, drinks sweetened with fructose, coffee, dairy products, vegetables and fruits. Diet correction is an important and necessary step in the prevention and treatment of НU. The article reviews the basic principles of dietary management in HU and provides dietary recommendations for patients. For effective prevention and treatment of НU, a mandatory correction of the diet is required.

Dietary Acid Load Is Positively Associated with the Incidence of Hyperuricemia in Middle-Aged and Older Korean Adults: Findings from the Korean Genome and Epidemiology Study

Hyperuricemia has been associated with a number of chronic diseases, such as type 2 diabetes mellitus, hypertension, and cardiovascular diseases. Dietary acid load plays a key role in regulating uric acid levels. We hypothesized that potential renal acid load (PRAL) and net endogenous acid production (NEAP) score would be positively associated with the incidence of hyperuricemia. Data from the Health Examinees study, a part of the Korean Genome and Epidemiology Study were used. The PRAL and NEAP scores were calculated to evaluate the dietary acid load. Hyperuricemia was defined as follows: >7.0 mg/dL and >6.0 mg/dL of serum uric acid levels in men and women, respectively. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of hyperuricemia. We identified 2500 new cases of hyperuricemia during a mean follow-up of 5.0 years (223,552 person years). The participants in the highest quartiles of the PRAL and NEAP score had 21% (HR: 1.21, 95% CI: 1.07–1.35, p for trend <0.0001) and 17% (HR: 1.17, 95% CI: 1.04–1.31, p for trend <0.0001) higher risks for hyperuricemia, respectively, than those in the lowest quartiles, after adjusting for covariates. In this prospective cohort study, a higher dietary acid load was positively associated with a higher incidence of hyperuricemia in Korean adults. This suggests that an alkaline diet may be an effective strategy to reduce the future risk of elevated uric acid levels.

Current applications of capillary electrophoresis-mass spectrometry for the analysis of biologically important analytes in urine (2017 to mid-2021): A review

Capillary electrophoresis coupled online with mass detection is a modern tool for analyzing wide ranges of compounds in complex samples, including urine. Capillary electrophoresis with mass spectrometry allows the separation and identification of various analytes spanning from small ions to high molecular weight protein complexes. Similarly to the much more common liquid chromatography‐mass spectrometry techniques, the capillary electrophoresis separation reduces the complexity of the mixture of analytes entering the mass spectrometer resulting in reduced ion suppression and a more straightforward interpretation of the mass spectrometry data. This review summarizes capillary electrophoresis with mass spectrometry studies published between the years 2017 and 2021, aiming at the determination of various compounds excreted in urine. The properties of the urine, including its diagnostical and analytical features and chemical composition, are also discussed including general protocols for the urine sample preparation. The mechanism of the electrophoretic separation and the instrumentation for capillary electrophoresis with mass spectrometry coupling is also included. This review shows the potential of the capillary electrophoresis with mass spectrometry technique for the analyses of different kinds of analytes in a complex biological matrix. The discussed applications are divided into two main groups (capillary electrophoresis with mass spectrometry for the determination of drugs and drugs of abuse in urine and capillary electrophoresis with mass spectrometry for the studies of urinary metabolome).

The efficacy and safety of citrate mixture vs sodium bicarbonate on urine alkalization in Chinese primary gout patients with benzbromarone: a prospective, randomized controlled study

Objectives

To compare the efficacy and safety of citrate mixture and sodium bicarbonate on urine alkalization in gout patients under benzbromarone treatment.

Methods

A prospective, randomized, parallel controlled trial was conducted among 200 gout patients in the dedicated gout clinic of the Affiliated Hospital of Qingdao University. The participants were randomly divided into two groups (1:1), sodium bicarbonate group (3 g/day) and citrate mixture group (7 g/day). All patients were prescribed with 25 mg/day benzbromarone at initiation and maintained at a dose of 50 mg/day. Clinical and biochemical data were collected at each follow-up time point (baseline, weeks 2, 4, 8 and 12).

Results

A total of 182 patients completed the 12-week urine alkalization study. The urine pH value of both groups increased significantly from the baseline to the final follow-up time point (sodium bicarbonate group, 5.50–6.00, P < 0.05; citrate mixture group, 5.53–5.93, P < 0.05). While the comparisons regarding urine pH between treatment groups showed no significant differences for each time point. The estimated glomerular filtration rate (eGFR) dropped significantly after 12 weeks’ trial in the sodium bicarbonate group (P < 0.01), while it was comparable between baseline and the last follow-up (P > 0.05) in the citrate mixture group. Results of urine analysis showed that the incident rate of occult blood in the sodium bicarbonate group was higher than that in the citrate mixture group (38 vs 24%, P < 0.05), accompanied by a similar occurrence of kidney stones. After 12-week follow-up, the frequency of twice gout flare in the citrate mixture group was significantly lower than that in sodium bicarbonate group (4 vs 12%, P = 0.037). No treatment-emergent adverse events occurred.

Conclusion

The efficacy of citrate mixture on urine alkalization is comparable to sodium bicarbonate under benzbromarone treatment without significant adverse events. Citrate mixture is superior to sodium bicarbonate in lowering the incidence of urine occult blood and the frequency of gout attacks.

Trial registration

Registered with ChiCTR (http://www.chictr.org.cn), No. ChiCTR1800018518.

Estimates of renal net acid excretion and their relationships with serum uric acid and hyperuricemia in a representative German population sample

BACKGROUND/OBJECTIVE

Preliminary interventional data suggest that a reduction of dietary acid load raises renal uric acid excretion and decreases serum uric acid (SUA). In line with this, in a recent cross-sectional analysis of a representative adult population sample, a higher potential renal acid load (PRAL) was found to associate with higher SUA levels. Against this background, we re-examined the relationship of the body's acid load with SUA and hyperuricemia using nutrition-derived estimates of renal net acid excretion (NAE).

SUBJECTS/METHODS

Cross-sectional analyses were performed in n = 6894 participants (18-79 y) of the German Health Interview and Examination Survey for Adults (DEGS1). Two different approaches were used to estimate NAE, one based on the sum of food frequency questionnaire (FFQ)-derived PRAL and body-surface area-derived organic acids (eNAE_PRAL+OA) and the other based on FFQ-derived protein and potassium intake ratios (eNAE_Prot/K). The associations of eNAE_PRAL+OA and eNAE_Prot/K with SUA were analyzed in multiple linear regression models. Multiple logistic regressions were used to calculate odds ratios (OR) for hyperuricemia comparing higher (T3) and lower (T1) tertiles of the NAE estimates.

RESULTS

After adjusting for relevant confounders, eNAE_PRAL+OA (p = 0.0048) and eNAE_Prot/K (p = 0.0023) were positively associated with SUA. In addition, participants with a higher eNAE_PRAL+OA or eNAE_Prot/K had higher ORs for having hyperuricemia (OR: 1.73, 95% CI: 1.24-2.40, OR: 1.51, 95% CI: 1.10-2.08, respectively).

CONCLUSION

The results substantiate findings of a previous analysis that dietary acid load is a potential influencing factor on SUA. This implicates that a lower dietary acid load may have beneficial effects on SUA.

Development of Low-Cost AuNP-Based Aptasensors with Truncated Aptamer for Highly Sensitive Detection of 8-Oxo-dG in Urine

8-Oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG), an oxidized form of guanosine residues, is a critical biomarker for various cancers. Herein, a sensitive citrate-capped gold nanoparticle-based aptasensor device has been developed for the detection of 8-oxo-dG in urine. We previously designed a 38-nt anti-8-oxo-dG-aptamer by a computer simulation and the experimental validation has been performed in the present work. The analytical performance of the 38-nt aptamer from the in silico design was compared with the parent 66-nt aptamer. This assay is based on the principle of salt-induced aggregation of citrate-capped gold nanoparticles. Based on this sensing mechanism, the difference between the absorbance in the presence and absence of 8-oxo-dG at λ = 525 nm (ΔA525) increased linearly as a function of 8-oxo-dG concentrations in the ranges of 10-100 and 15-100 nM for 38-nt and 66-nt aptasensors, respectively. This method can provide detection limits of 6.4 nM for 8-oxo-dG in the 38-nt aptasensor and 13.2 nM in the 66-nt aptasensor. Similar to the 66-nt aptamer, the shortened aptamer, 38-nt long, can provide high sensitivity and selectivity with rapid detection time. In addition, using the 38-nt aptamer as a recognition component in the developed portable low-cost device showed high sensitivity in the detection range of 15-100 nM with a detection limit of 12.9 nM, which is much lower than the threshold value (280 nM) for normal human urine. This easy-to-use device could effectively and economically be utilized for monitoring 8-oxo-dG in real urine samples and potentially serve as a prototype for a commercial device.

Safety, efficacy and tolerability of a combination micronutrient and polyherbal preparation (GoutFighter TM) for gout: a single-arm open-label pilot study

BACKGROUND

To evaluate the safety, efficacy and tolerability of a combination micronutrient and polyherbal preparation (GoutFighter ^TM) for gout management.

METHODS

A single arm, open-label pilot study was conducted at the National Hospital for Traditional Medicine in Vietnam. Participants (n=35 recruited) diagnosed with chronic gout received four tablets of GoutFighter ^TM daily over a 45-day period. Efficacy was assessed by changes in pain, swelling and blood uric acid levels, with concurrent safety and tolerability assessments.

RESULTS

A total of 27 (85.2% male) participants (mean ± SD age, 54.2 ± 12.5 years; BMI, 24.2 ± 3.6 kg/m²) with gout (median [IQR], years since diagnosis 4.0 [3.0-8.0]) completed intervention. In relation to safety, there were no significant changes in vital signs, blood biochemistry or cell counts. In regard to efficacy, the degree of perceived pain and frequency of joint swelling significantly declined after 15 and 30 days of treatment, respectively, and remained so until the end of trial. Mean blood uric acid levels also declined by 25.8 μmol/L (95% CI, 3.7 to 48.0, p=0.024). Overall, the predominance of participants (96.3%) responded favorably to treatment (p<0.0001) and GoutFighter ^TM was well tolerated, with no serious adverse events.

CONCLUSION

Clinically relevant doses of GoutFighter ^TM were found to be generally safe, well-tolerated and effective for the short-term, symptomatic relief of chronic gout. GoutFighter ^TM appears to be suitable as an adjunctive treatment in lifestyle programs for gout management, and further investigation in placebo-controlled trials is therefore warranted.

Use of Nanotrap particles for the capture and enrichment of Zika, chikungunya and dengue viruses in urine

Nanotrap^® (NT) particles are hydrogel microspheres developed for target analyte separation and discovery applications. NT particles consist of cross-linked N-isopropylacrylamide (NIPAm) copolymers that are functionalized with a variety of chemical affinity baits to enable broad-spectrum collection and retention of target proteins, nucleic acids, and pathogens. NT particles have been previously shown to capture and enrich arboviruses including Rift Valley fever and Venezuelan equine encephalitis viruses. Yet, there is still a need to enhance the detection ability for other re-emerging viruses such as Zika (ZIKV), chikungunya (CHIKV), and dengue (DENV) viruses. In this study, we exploited NT particles with different affinity baits, including cibacron blue, acrylic acid, and reactive red 120, to evaluate their capturing and enrichment capability for ZIKV, DENV and CHIKV in human fluids. Our results demonstrate that CN1030, a NT particle conjugated with reactive red 120, can recover between 8-16-fold greater genomic copies of ZIKV, CHIKV and DENV in virus spiked urine samples via RT-qPCR, superior to the other chemical baits. Also, we observed that CN1030 simultaneously enriched ZIKV, CHIKV and DENV in co-infection-based settings and could stabilize ZIKV, but not CHIKV infectivity in saliva spiked samples. CN1030 enriched viral detection at various viral concentrations, with significant enhancement observed at viral titers as low as 100 PFU/mL for ZIKV and 10 PFU/mL for CHIKV. The detection of ZIKV was further enhanced with NT particles by processing of larger volume urine samples. Furthermore, we developed a magnetic NT particle, CN3080, based on the same backbone of CN1030, and demonstrated that CN3080 could also capture and enrich ZIKV and CHIKV in a dose-dependent manner. Finally, in silico docking predictions support that the affinity between reactive red 120 and ZIKV or CHIKV envelope proteins appeared to be greater than acrylic acid. Overall, our data show that NT particles along with reactive red 120 can be utilized as a pre-processing technology for enhancement of detecting febrile-illness causing viruses.

Combined Supplementation with Glycine and Tryptophan Reduces Purine-Induced Serum Uric Acid Elevation by Accelerating Urinary Uric Acid Excretion: A Randomized, Single-Blind, Placebo-Controlled, Crossover Study

The authors previously confirmed the serum uric acid-lowering effects of the combination of glycine and tryptophan in subjects with mild hyperuricemia. This study examined whether combined supplementation with glycine and tryptophan suppressed the elevation in serum uric acid levels caused by purine ingestion and accelerated urinary uric acid excretion in subjects with lower urate excretion using a randomized, single-blind, placebo-controlled, crossover clinical trial design. Healthy Japanese adult males with lower urate excretion ingested water containing purines in addition to dextrin (placebo), tryptophan, glycine, or a glycine and tryptophan mixture. The combined supplementation with glycine and tryptophan significantly reduced the elevated serum uric acid levels after purine ingestion. Glycine alone and in combination with tryptophan significantly increased urinary uric acid excretion and urate clearance compared with the effects of the placebo. Urinary pH increased by the ingestion of the mixture. These results suggested that the improved water solubility of uric acid due to increased urinary pH contributed to the increase of urinary uric acid excretion.

Swine diets impact manure characteristics and gas emissions: Part I sulfur level

Sulfur is an essential nutrient for animal growth but is also associated with odor and morbidity of animals from swine operations. A study was conducted to determine the effects of increasing dietary S levels in swine diets on DM, pH, C, N, S, VFA, indole, and phenol concentrations in the manure, and on the emissions of C-, N-, and S-containing gases. A total of 24 gilts averaging 152 kg BW were fed diets containing 0.19, 0.30, 0.43, or 0.64% dietary S, as supplied by CaSO₄, for 31 d, with an ADFI of 3.034 kg d^-1. Feces and urine were collected after each feeding and added to manure storage containers. At the end of the study, manure slurries were monitored for gas emissions and chemical properties. Increasing dietary S lowered manure pH by 0.3 units and increased DM, N, and S by 10% for each 1.0 g S increase kg^-1 feed intake. Increased dietary S increased NH₃, sulfide, butanoic, and pentanoic acid concentrations in manure. Carbon and N emissions were not significantly impacted by dietary S, but S emissions in the form of hydrogen sulfide (H₂S) increased by 8% for each 1.0 g S increase kg^-1 feed intake. Odor increased by 2% for each 1.0 g increase of S consumed kg^-1 feed intake. Phenolic compounds and H₂S were the major odorants emitted from manure that increased with increasing dietary S.

Uric Acid and Plant-Based Nutrition

Plant-based diets (PBDs) are associated with decreased risk of morbidity and mortality associated with important noncommunicable chronic diseases. Similar to animal-based food sources (e.g., meat, fish, and animal visceral organs), some plant-based food sources (e.g., certain soy legume products, sea vegetables, and brassica vegetables) also contain a high purine load. Suboptimally designed PBDs might consequently be associated with increased uric acid levels and gout development. Here, we review the available data on this topic, with a great majority of studies showing reduced risk of hyperuricemia and gout with vegetarian (especially lacto-vegetarian) PBDs. Additionally, type of ingested purines, fiber, vitamin C, and certain lifestyle factors work in concordance to reduce uric acid generation in PBDs. Recent limited data show that even with an exclusive PBD, uric acid concentrations remain in the normal range in short- and long-term dieters. The reasonable consumption of plant foods with a higher purine content as a part of PBDs may therefore be safely tolerated in normouricemic individuals, but additional data is needed in hyperuricemic individuals, especially those with chronic kidney disease.

Metabolic Syndrome Features: Is There a Modulation Role by Mineral Water Consumption? A Review

Metabolic syndrome (MetSyn) promotes, among others, the development of atherosclerotic cardiovascular disease and diabetes. Its prevalence increases with age, highlighting the relevance of promoting precocious MetSyn primary prevention and treatment with easy-to-implement lifestyle interventions. MetSyn features modulation through mineral water consumption was reviewed on Pubmed, Scopus and Google Scholar databases, using the following keywords: metabolic syndrome, hypertension, blood pressure (BP), cholesterol, triglycerides, apolipoprotein, chylomicron, very low-density lipoprotein, low-density lipoprotein, high-density lipoprotein (HDL), glucose, insulin, body weight, body mass index, waist circumference (WC), obesity and mineral(-rich) water. Twenty studies were selected: 12 evaluated BP, 13 assessed total-triglycerides and/or HDL-cholesterol, 10 analysed glucose and/or 3 measured WC. Mineral waters were tested in diverse protocols regarding type and composition of water, amount consumed, diet and type and duration of the study. Human and animal studies were performed in populations with different sizes and characteristics. Distinct sets of five studies showed beneficial effects upon BP, total-triglycerides, HDL-cholesterol and glucose. WC modulation was not reported. Minerals/elements and active ions/molecules present in mineral waters (and their pH) are crucial to counterbalance their inadequate intake and body status as well as metabolic dysfunction and increased diet-induced acid-load observed in MetSyn. Study characteristics and molecular/physiologic mechanisms that could explain the different effects observed are discussed. Further studies are warranted for determining the mechanisms involved in the putative protective action of mineral water consumption against MetSyn features.

Hyperuricemia and acute gout after laparoscopic sleeve gastrectomy

The aim of this study was to evaluate the prevalence of hyperuricemia and acute gout after laparoscopic sleeve gastrectomy (LSG). Risk factors for developing gout were also examined. Eighty-five patients underwent LSG were enrolled in this prospective study. Serum uric acid levels, gout attacks and total water levels % derived by bioimpedance were examined pre-operatively and 1 month post-operatively. Hyperuricemia was identified in 30.6% pre-operatively and in 18.82% of patients post-operatively. From the patients' group with pre-operative hyperuricemia, 53.9% were normalized, 46.2% had increased uric acid post-operatively while gout was observed in 11.5%. From the patients group without pre-operative hyperuricemia, hyperuricemia and gout were observed in 6.8% and 5.1% post-operatively, respectively. The relative risk for developing hyperuricemia was 6.2 (95% confidence interval [CI] 2.2-17.8) and for developing gout was 2.3 (95% CI 2.2-17.8). Statistical significant differences for gout among the groups with and without gout were indicated concerning pre-operative use of medications (P < 0.001), age (P = 0.025), post-operative uric acid levels (P < 0.001) and post-operative total water levels % (P = 0.048). The prevalence of hyperuricemia was 18.8% and gout attack of 7.1% 1 month after LSG. From the cohort of patients with pre-operative hyperuricemia, a significant proportion normalized uric acid, while 11.5% developed gout. Patients without hyperuricemia pre-operatively developed hyperuricemia and gout in 6.8% and 5.1% post-operatively, respectively. The patients who had gout were younger and had 37% water levels post-operatively.

Vegetarian diet and risk of gout in two separate prospective cohort studies

BACKGROUNDS & AIMS

Plant-based diets may target multiple pathways in gout pathogenesis (uric acid reduction and anti-inflammation) while improving gout associated cardiometabolic comorbidities. We aim to prospectively examine the relationship between a vegetarian diet and gout, and to explore if this relationship is independent of hyperuricemia.

METHODS

We followed 4903 participants in the Tzu Chi Health Study (Cohort1, recruited in 2007-2009) and 9032 participants in the Tzu Chi Vegetarian Study (Cohort2, recruited in 2005) until end of 2014. Baseline serum uric acid was measured in Cohort1. Vegetarian status was assessed through a diet questionnaire that includes dietary habits and a food frequency questionnaire. Incidence of gout was ascertained by linkage to the National Health Insurance Database. Hazard Ratio of gout in vegetarians versus nonvegetarians was assessed by Cox regression, adjusted for age, sex, lifestyle and metabolic risk factors. Hyperuricemia was additionally adjusted in Cohort1.

RESULTS

In Cohort1, lacto-ovo vegetarians had the lowest uric acid concentration, followed by vegans, then nonvegetarians (men: 6.05, 6.19, 6.32 mg/dL, respectively; women: 4.92, 4.96, 5.11 mg/dL, respectively); 65 gout cases occurred in the 29,673 person-years of follow-up; vegetarians experienced a lower risk of gout (without adjustment for hyperuricemia: HR: 0.33; 95% CI: 0.14, 0.79; with adjustment for hyperuricemia: HR: 0.40; 95% CI: 0.17, 0.97). In Cohort2, 161 gout cases occurred in the 83,019 person-years follow-up, and vegetarians also experienced a lower risk of gout (HR: 0.61; 95% CI: 0.41, 0.88).

CONCLUSION

Taiwanese vegetarian diet is associated with lower risk of gout. This protective association may be independent of baseline hyperuricemia.

STUDY REGISTERED

URL: https://www.clinicaltrials.gov. Unique Identifier: NCT03470584.

Prospective relation of adolescent citrate excretion and net acid excretion capacity with blood pressure in young adulthood

Experimental data and observational studies in adults suggest that even subtle changes in acid-base balance, indicative of a higher systemic proton load, are related to higher blood pressure (BP) levels and an increased hypertension risk. However, these associations have not been investigated during growth. The kidney is the central organ in regulating excretion of nonvolatile acids, and renal citrate excretion has been shown to be a sensitive, noninvasive marker of changes in systemic acid balance. We thus analyzed the prospective relation of 24-h citrate excretion, as well as net acid excretion capacity (NAEC; a noninvasive indicator of the renal ability to excrete protons), during adolescence (boys: 10-15 yr; girls: 9-14 yr) with BP levels in young adulthood (18-30 yr) in 374 healthy participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study. In linear-regression analyses adjusted for age, sex, 24-h urinary excretions of sodium and potassium, as well as further relevant confounders, a 1-mmol/1.73 m²/day higher adolescent citrate excretion was related to 1.2 mmHg lower systolic BP ( P = 0.02) but not to diastolic BP ( P = 0.6). A 10-mEq higher NAEC during adolescence was related to 1.7 mmHg lower systolic BP in young men, but this association was statistically nonsignificant ( P = 0.07) after multivariable adjustment. Additional adjustment for adult body mass index did not alter these findings. To conclude, subtle changes in systemic acid-base balance during adolescence are already indicative for later BP. Potential sex differences in these associations should be investigated in further studies.

Low urine pH affects the development of metabolic syndrome, associative with the increase of dyslipidemia and dysglycemia: Nationwide cross-sectional study (KNHANES 2013-2015) and a single-center retrospective cohort study

INTRODUCTION

Low urine pH (UpH) and high serum uric acid are considered evidence of metabolic disorders. The effect of low UpH on the development of metabolic syndrome (MetS) is less clear than that of high serum uric acid. We investigated the association between low UpH on the development of MetS and its components: central obesity, dyslipidemia, hypertension, and dysglycemia.

METHODS

Two studies were conducted based on 2 datasets. The cross-sectional study included 14,511 subjects aged 19-80 years, based on the Korea National Health and Nutrition Examination Survey in 2013-2015. The retrospective cohort study included 3,453 subjects aged 19-80 years without MetS at the first checkup, who underwent at least 3 health checkups at a single tertiary hospital between 2011 and 2017. UpH was measured using an automatic urine analyzer in the range of 5.0-9.0 at first visit.

RESULTS

In the cross-sectional study, low UpH (= 5.0) was associated with the prevalence of MetS (odds ratio [OR] = 1.480, 95% confidence interval [CI] 1.334-1.643, p<0.001), particularly central obesity, dyslipidemia, and dysglycemia (OR ranges 1.282-1.422, p<0.001, all). In the retrospective cohort study, compared with the highest UpH subgroup, the lowest UpH subgroup (= 5.0) was associated with higher risk of MetS development (hazard ratio = 1.394, 95% CI 1.096-1.772, p = 0.007). The incident risk of MetS increased from the highest to lowest UpH subgroups (p for trend = 0.020), among which dyslipidemia and dysglycemia increased (p for trend <0.01, all).

CONCLUSION

Low UpH can be used as a surrogate marker of MetS and affects the development of MetS, associative with the increase of dyslipidemia and dysglycemia in those without MetS. If UpH is ≤5.0, efforts to prevent metabolic disorders are warranted.

Effect of immediate and prolonged GLP-1 receptor agonist administration on uric acid and kidney clearance: Post-hoc analyses of four clinical trials

AIMS

To determine the effects of glucagon-like peptide (GLP)-1 receptor agonists (RA) on uric acid (UA) levels and kidney UA clearance.

MATERIAL AND METHODS

This study involved post-hoc analyses of 4 controlled clinical trials, which assessed actions of GLP-1RA administration on kidney physiology. The immediate effects of GLP-1RA exenatide infusion vs placebo were determined in 9 healthy overweight men (Study-A) and in 52 overweight T2DM patients (Study-B). The effects of 12 weeks of long-acting GLP-1RA liraglutide vs placebo in 36 overweight T2DM patients (Study-C) and of 8 weeks of short-acting GLP-1RA lixisenatide vs once-daily titrated insulin glulisine in 35 overweight T2DM patients (Study-D) were also examined. Plasma UA, fractional (inulin-corrected) and absolute urinary excretion of UA (UE_UA ) and sodium (UE_Na ), and urine pH were determined.

RESULTS

Median baseline plasma UA level was 5.39 to 6.33 mg/dL across all studies (17%-22% of subjects were hyperuricaemic). In Study-A, exenatide infusion slightly increased plasma UA (+0.07 ± 0.02 mg/dL, P = .04), and raised absolute-UE_UA (+1.58 ± 0.65 mg/min/1.73 m² , P = .02), but did not affect fractional UE_UA compared to placebo. Fractional UE_UA and absolute UE_UA correlated with increases in urine pH (r:0.86, P = .003 and r:0.92, P < .001, respectively). Fractional UE_UA correlated with increased fractional UE_Na (r:0.76, P = .02). In Study-B, exenatide infusion did not affect plasma UA, but increased fractional UE_UA (+0.76 ± 0.38%, P = .049) and absolute UE_UA (+0.75 ± 0.27 mg/min/1.73 m² , P = .007), compared to placebo. In regression analyses, both parameters were explained by changes in urine pH and, in part, by changes in UE_Na . In Study-C, liraglutide treatment did not affect plasma UA, UE_UA, UE_Na or urine pH, compared to placebo. In Study-D, lixisenatide treatment increased UE_Na and urine pH from baseline, but did not affect plasma UA or UE_UA .

CONCLUSION

Immediate exenatide infusion increases UE_UA in overweight healthy men and in T2DM patients, probably by inhibiting Na⁺ /H⁺ -exchanger type-3 in the renal proximal tubule. Prolonged treatment with a long-acting or short-acting GLP-1RA does not affect plasma UA or UE_UA in T2DM patients with normal plasma UA levels and at relatively low cardiovascular risk. Our results suggest that the cardio-renal benefits of GLP-1RA are not mediated through changes in UA.

Long-term in vivo evolution of high-purity Mg screw degradation - Local and systemic effects of Mg degradation products

Magnesium (Mg) based materials are the focus of research for use as degradable materials in orthopedics and cranio-maxillofacial surgery. However, corrosion rate control and biosecurity are still the key issues that need to be solved prior to their clinical applications. In the present study, as-rolled high-purity magnesium (HP Mg, 99.99 wt%) screws were implanted in rabbit tibiae for up to 52 weeks in order to investigate their long-term in vivo degradation and the local and systemic effects of their degradation products. A series of long-term monitoring were performed at various time points (4w, 12w, 26w and 52w) after implantation using numerous investigations such as micro-CT assay, histomorphometric analysis, local micro-environment testing and biochemical analysis of serum and urine. It was revealed that HP Mg screws had a uniform degradation morphology and a slow degradation rate in vivo during the period of 52 weeks. Their degradation products not only increased the local pH values but also changed the local Mg²⁺ ions concentration and gas cavity area in the peri-implant tissues in a dynamic manner. More importantly, both the new bone formation and bone-implant contact rate were increased at bone-implant interfaces at 26 weeks and 52 weeks post-implantation. Furthermore, neither abnormal elevation of serum magnesium and urine magnesium level, nor liver and kidney dysfunction were detected during the monitoring period of 26 weeks. All these results of long-term investigation suggest that HP Mg screws possess a slow degradation rate, desirable bone repair capacity and long-term local/systemic biosafety, and consequently may have good potential for application as bone fixation devices.

STATEMENT OF SIGNIFICANCE

The corrosion resistance control and biosecurity issues of Mg alloys limited their clinical applications in some extent. Mg purification is another effective way to improve corrosion resistance of Mg-based materials. However, the long-term in vivo degradation of high-purity magnesium (HP Mg) and the local and systemic effects of its degradation products have not been fully investigated yet, which are the key factors to determine the clinical application prospect of HP Mg. Especially the changes in peri-implant microenvironment may greatly influence the local physiological response and bone repair. In this study, the long-term evolution tendency of in vivo degradation behavior of HP Mg screws was discovered from the view of space-time. Furthermore, not only the dynamic changes of local microenvironment and the long-term evolution process of bone repair, but also the dynamic systemic responses were systematically revealed. Conclusions of this study may help us to further understand the long-term in vivo evolution of HP Mg degradation and the local/systemic effects of its degradation products and help to guide the design of biodegradable bone fixation material.

Are Doctors the Best People to Manage Gout? Is There a Role for Nurses and Pharmacists?

PURPOSE OF REVIEW

To discuss alternate models of long-term gout management RECENT FINDINGS: Nurse-led care of gout appears to improve the uptake of and adherence to urate-lowering treatment in a research setting. Less impressive improvements were achieved with pharmacist-led remote management of gout; however, both strategies were more effective than usual primary care provider management of gout. Individualised education about gout, patient involvement in decision-making, and access to trained support in managing side-effects and gout flares can improve the uptake of fine and adherence to urate-lowering treatment. This may be best achieved with nurse-led care of gout. However, further research is required to evaluate if the model of nurse-led care of gout can be implemented in routine clinical practice and in different healthcare systems.

Dietary Acid Load and Potassium Intake Associate with Blood Pressure and Hypertension Prevalence in a Representative Sample of the German Adult Population

Diets rich in fruits and vegetables, like the Dietary Approaches to Stop Hypertension (DASH)-diet, are usually characterized by high potassium intake and reduced dietary acid load, and have been shown to reduce blood pressure (BP). However, the relevance of potential renal acid load (PRAL) for BP has not been compared with the relevance to BP of urinary biomarker (K-urine)- and dietary food frequency questionnaire (K-FFQ)-based estimates of potassium intake in a general adult population sample. For 6788 participants (aged 18–79 years) of the representative German Health-Interview and Examination Survey for Adults (DEGS1), associations of PRAL, K-urine, and K-FFQ with BP and hypertension prevalence were cross-sectionally examined in multivariable linear and logistic regression models. PRAL was significantly associated with higher systolic BP (p = 0.0002) and higher hypertension prevalence (Odds ratio [OR] high vs. low PRAL = 1.45, p = 0.0004) in models adjusted for age, sex, body mass index (BMI), estimated sodium intake, kidney function, relevant medication, and further important covariates. Higher estimates of K-FFQ and K-urine were related to lower systolic BP (p = 0.04 and p < 0.0001) and lower hypertension prevalence (OR = 0.82, p = 0.04 and OR = 0.77, p = 0.02) as well as a lower diastolic BP (p = 0.03 and p = 0.0003). Our results show, for the first time in a comparative analysis of a large representative population sample, significant relationships of BP and hypertension prevalence with questionnaire- and biomarker-based estimates of potassium intake and with an estimate of dietary acid load.

Dietary Potential Renal Acid Load Is Positively Associated with Serum Uric Acid and Odds of Hyperuricemia in the German Adult Population

Background

Initial interventional data indicate that a reduction in dietary acid load (e.g., by an increased consumption of alkalizing fruit and vegetables) can increase renal uric acid excretion and decrease serum uric acid (SUA).

Objective

Against this background, we examined the association between dietary potential renal acid load (PRAL) and SUA in a representative population sample.

Methods

Cross-sectional analyses were performed in 6894 participants (aged 18-79 y) of the German Health Interview and Examination Survey for Adults (DEGS1). Dietary intake was assessed with a food-frequency questionnaire. Nutritive acid load and the intake of uric acid equivalents (UAEs) were characterized by assigning PRAL and UAE values to reported food consumption. In multiple linear regression models, the associations of PRAL, UAEs, and relevant food groups with SUA were analyzed. Multiple logistic regressions were used to calculate ORs for hyperuricemia comparing lower and upper tertiles of the predictors.

Results

After adjustment for relevant confounders, PRAL (P = 0.003), alcohol (P < 0.0001), and UAE (P = 0.03) intakes were positively associated with SUA, whereas the intake of dairy products and fruit and vegetables was inversely associated (both P < 0.0001). Subgroup analyses among participants without interacting medication use confirmed these results. In addition, participants with lower PRAL had lower odds for hyperuricemia (OR: 0.60; 95% CI: 0.43, 0.83).

Conclusions

Apart from observing known dietary influences on SUA, we found in this population-based, cross-sectional study in adults that low PRAL may represent a potentially SUA-reducing dietary pattern. This highlights dietary alkalization as a possible nonpharmacologic option to influence elevated SUA concentrations.

Risk Factors for Collegiate Swimmers Hospitalized With Exertional Rhabdomyolysis

OBJECTIVE

To identify midseason risk factors for symptomatic exertional rhabdomyolysis (sER) in swimmers after a novel upper body workout.

DESIGN

Retrospective (1) survey and (2) analyses of observational laboratory data conducted over a 16-week training period, 2 months before sER.

SETTING

Midwest University.

PARTICIPANTS

Thirty-four collegiate swimmers.

INDEPENDENT VARIABLES

(1) Motivation, symptoms, and supplements for survey variables. (2) Changes (midseason minus preseason) in body composition, blood pressure (BP), urinary measures, and protein shake ingestion for laboratory variables.

MAIN OUTCOME MEASURES

Swimmers were categorized in hospitalized (H), treated and released from hospital (RH), and nonhospitalized (NH) groups for analyses.

RESULTS

(1) Six swimmers were in the H group (17.6%; 3 male/3 female) and 7 in the RH group (20.6%; 3 male/4 female). Nonsignificant trend toward H swimmers relating more upper body soreness (≥9/10) than RH (8/10) and NH (6/10) swimmers (P > 0.05) while reporting "felt bad and workout went poorly" (P = 0.009). H and RH swimmers reported more arm locking during the workout (P = 0.04) and brown urine after arm competition compared with NH-group swimmers (P = 0.03). (2) Increases in right systolic (P = 0.01) and left diastolic (P = 0.02) BP, with trends toward decreased left arm lean mass (P = 0.06) in H compared with RH and NH swimmers. Female H swimmers had more acidic urine (pH = 5.50 vs 6.9; P = 0.004), less volume, and higher specific gravity than RH + NH swimmers. All H swimmers regularly ingested protein shakes after workouts.

CONCLUSIONS

Risk factors for sER included exceptional motivation, extreme soreness, increased resting BP, acidic urine (females), and regular ingestion of protein shakes.

Latent association between low urine pH and low body weight in an apparently healthy population

Low urine pH, a plausible predictor for chronic kidney disease and metabolic disorders, is often observed in obese individuals. However, the association between low urine pH and low body weight is equivocal. We examined clinical parameters including urine pH and body mass index (BMI) in a cross-sectional study of 3629 apparently healthy Japanese adults aged 25-80 years who underwent a health-screening check-up. Urine pH was lower and the prevalence of proteinuria was significantly higher in subjects with BMI of ≥ 27.0 kg/m(2) compared with those with BMI of 21.0-22.9 kg/m(2). By contrast, hematuria was more prevalent in subjects with BMI of ≤ 20.9 kg/m(2). Logistic regression analysis showed that BMI of ≥ 27.0 kg/m(2) was significantly associated with low urine pH (≤ 5.5), which remained significant after adjustment for relevant confounders including age, sex, proteinuria, estimated glomerular filtration rate, urine density, hematuria, smoking status, and daily alcohol drinking. However, the association disappeared after further adjustment for serum uric acid. In contrast, the association between low urine pH and BMI of ≤ 19.0 kg/m(2) was significant after adjustment for age and sex and rather strengthened by the further adjustment for serum uric acid. In conclusion, low urine pH may be independently associated with low BMI. However, the underlying mechanisms of low urine pH in low body weight may differ from those in high body weight.

The Characterization of Feces and Urine: A Review of the Literature to Inform Advanced Treatment Technology

The safe disposal of human excreta is of paramount importance for the health and welfare of populations living in low income countries as well as the prevention of pollution to the surrounding environment. On-site sanitation (OSS) systems are the most numerous means of treating excreta in low income countries, these facilities aim at treating human waste at source and can provide a hygienic and affordable method of waste disposal. However, current OSS systems need improvement and require further research and development. Development of OSS facilities that treat excreta at, or close to, its source require knowledge of the waste stream entering the system. Data regarding the generation rate and the chemical and physical composition of fresh feces and urine was collected from the medical literature as well as the treatability sector. The data were summarized and statistical analysis was used to quantify the major factors that were a significant cause of variability. The impact of this data on biological processes, thermal processes, physical separators, and chemical processes was then assessed. Results showed that the median fecal wet mass production was 128 g/cap/day, with a median dry mass of 29 g/cap/day. Fecal output in healthy individuals was 1.20 defecations per 24 hr period and the main factor affecting fecal mass was the fiber intake of the population. Fecal wet mass values were increased by a factor of 2 in low income countries (high fiber intakes) in comparison to values found in high income countries (low fiber intakes). Feces had a median pH of 6.64 and were composed of 74.6% water. Bacterial biomass is the major component (25-54% of dry solids) of the organic fraction of the feces. Undigested carbohydrate, fiber, protein, and fat comprise the remainder and the amounts depend on diet and diarrhea prevalence in the population. The inorganic component of the feces is primarily undigested dietary elements that also depend on dietary supply. Median urine generation rates were 1.42 L/cap/day with a dry solids content of 59 g/cap/day. Variation in the volume and composition of urine is caused by differences in physical exertion, environmental conditions, as well as water, salt, and high protein intakes. Urine has a pH 6.2 and contains the largest fractions of nitrogen, phosphorus, and potassium released from the body. The urinary excretion of nitrogen was significant (10.98 g/cap/day) with urea the most predominant constituent making up over 50% of total organic solids. The dietary intake of food and fluid is the major cause of variation in both the fecal and urine composition and these variables should always be considered if the generation rate, physical, and chemical composition of feces and urine is to be accurately predicted.

The association between a low urine pH and the components of metabolic syndrome in the Korean population: Findings based on the 2010 Korea National health and nutrition examination survey

BACKGROUND

Low urine pH is related to obesity and insulin resistance, which are components of metabolic syndrome (MS). The aim of this study was to identify the relation between a low urine pH and MS after controlled for other covariates including demographic and lifestyle factors in adult Korean population.

MATERIALS AND METHODS

We analyzed data from the 2010 Korea National Health and Nutrition Examination Survey, a cross-sectional and nationally representative survey and 1960 men and 2702 women were included in this study. Study subjects were divided into the group with urine pH <5.5 and the group with urine pH ≥5.5 refer to literature. We then evaluated the association between low urine pH and MS.

RESULTS

After adjusting for age, sex, smoking status, drinking status, regular exercise, and blood urea nitrogen level, the odds ratio (OR) for the presence of MS in the group with urine pH <5.5 was 1.350 (95% confidence interval [95% CI]: 1.158-1.573) using the American Heart Association/National Heart, Lung, and Blood Institute criteria or 1.304 (95% CI: 1.082-1.572) using the International Diabetes Federation criteria. Among MS components, elevated fasting glucose (OR: 1.231, 95% CI: 1.058-1.433, P = 0.007) and elevated triglyceride (TG) (OR: 1.389, 95% CI: 1.189-1.623, P < 0.001) showed a significantly high OR.

CONCLUSION

The findings confirmed that low urine pH is associated with MS in the Korean population. Among MS components, elevated fasting glucose and elevated TG showed a significantly high OR.