Association of low urine pH as a metabolic feature with abdominal obesity

Effect of pH, Norepinephrine and Glucose on Metabolic and Biofilm Activity of Uropathogenic Microorganisms

Urinary tract infection (UTIs) aremainly caused by a number of anatomical and physiological dysfunctions, but there are also some iatrogenic factors, including the use of certain medications, that contribute to the development of UTIs. The virulence of bacteria that colonize the urinary tract may be modified by pH and by the presence of soluble substances in urine, such as norepinephrine (NE) and glucose. In this work, we studied the influence of NE and glucose across a range of pHs (5, 7, 8) on the biomass, matrix production and metabolism of uropathogenic strains of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and Enterococcus faecalis. We used Congo red and gentian violet to stain the extracellular matrix and biomass, respectively, of biofilms. The optical density of staining of the biofilms was measured using a multichannel spectrophotometer. The metabolic activity was analyzed by MTT assay. It was shown that NE and glucose stimulate biomass production both in the Gram-negative and Gram-positive uropathogens. The metabolic activity in the presence of glucose was higher at pH 5 for E. coli (in 4.0 ± 0.1 times), Ps. aeruginosa (in 8.2 ± 0.2 times) and Kl. pneumoniae (in 4.1 ± 0.2 times). Matrix production of Kl. pneumoniae increased under NE (in 8.2 ± 0.2 times) and in the presence of glucose (in 1.5 ± 0.3 times). Thus, NE and glucose in urine may lead to persistent UTI under patient stress and in the case of metabolic glucose disorders.

In Vitro Mimicking of Obesity-Induced Biochemical Environment to Study Obesity Impacts on Cells and Tissues

Obesity represents a heavy burden for modern healthcare. The main challenge facing obesity research progress is the unknown underlying pathways, which limits our understanding of the pathogenesis and developing therapies. Obesity induces specific biochemical environments that impact the different cells and tissues. In this piece of writing, we suggest mimicking obesity-induced in vivo biochemical environments including pH, lipids, hormones, cytokines, and glucose within an in vitro environment. The concept is to reproduce such biochemical environments and use them to treat the tissue cultures, explant cultures, and cell cultures of different biological organs. This will allow us to clarify how the obesity-induced biochemistry impacts such biological entities. It would also be important to try different environments, in terms of the compositions and concentrations of the constitutive elements, in order to establish links between the effects (impaired regeneration, cellular inflammation, etc.) and the factors constituting the environment (hormones, cytokines, etc.) as well as to reveal dose-dependent effects. We believe that such approaches will allow us to elucidate obesity mechanisms, optimize animal models, and develop therapies as well as novel tissue engineering applications.

Alkaline Urine in the Emergency Department Predicts Nitrofurantoin Resistance

BACKGROUND

The Proteeae group (i.e., Proteus species, Morganella morganii, and Providencia species) frequently causes urinary tract infections (UTIs) and is generally resistant to nitrofurantoin. Proteeae species can produce urease, which can increase urine pH.

OBJECTIVE

Our aim was to determine whether higher urine pH in the emergency department is associated with nitrofurantoin resistance.

METHODS

A single health system database of emergency department patients aged 18 years and older who received urinalysis between April 18, 2014, and March 7, 2017, was examined using χ² test and multivariable regression analysis.

RESULTS

Of 67,271 urine samples analyzed, 13,456 samples grew a single bacterial species. Urine cultures growing the Proteeae group were associated with significantly more alkaline urine than other bacteriuria cultures (odds ratio [OR] 2.20, 95% confidence interval [CI] 2.06-2.36; p < 0.001). The Proteeae species represented 4.4% of urine samples at pH 5-7, 24.4% at pH 8-9, and 40.0% at pH 9. At urine pH 5-7, 80.4% of urine samples were sensitive to nitrofurantoin; however, this percentage decreased to 66.1% for urine pH 8-9 and 54.6% for urine pH 9. Nitrofurantoin had the highest OR (2.10, 95% CI 1.85-2.39) among cefazolin, ciprofloxacin, and trimethoprim/sulfamethoxazole for bacteriuria sensitive to those antibiotics at urine pH 5-7. At urine pH 8-9 and 9, nitrofurantoin had the lowest OR among the antibiotics: 0.48 (95% CI 0.42-0.54) and 0.31 (95% CI 0.24-0.40), respectively (p < 0.001 for both).

CONCLUSIONS

Urine pH of 8 or higher is associated with high rates of nitrofurantoin resistance.

Low urine pH is a risk factor for low muscle mass: A new way to predict sarcopenia

AIMS

Sarcopenia, one of the primary diseases of the older adult population, is a condition characterized by loss of skeletal muscle mass, strength and functionality. Due to its considerable economic impact, preventive interventions for sarcopenia play an important role in the older adult population. Urine includes many indicators of physiology and pathophysiology. Urine analysis is used to diagnose many different diseases. The goal of this cohort study was to examine the relationship between urine pH level and skeletal muscle mass.

METHODS

This community-based cross-sectional study was carried out among 9712 Taiwanese individuals (4992 men and 4720 women). We used urine pH as an independent variable and skeletal muscle mass as a dependent variable. Bioelectric impedance analysis was used to measure the percentage of skeletal muscle mass (PSMM). We collected first fasting morning urine samples after overnight fasting, and urine pH was measured with a dipstick. In the by-sex and by-obesity analyses, we stratified the sample into two subgroups and a linear regression model was used for covariate adjustment.

RESULTS

In the fully adjusted model, all-subject analysis showed a statistically significant association between urine pH and the PSMM with a β coefficient of 0.820 (95% CI 0.615-1.025; P < 0.001). Additionally, by-sex analysis showed that urine pH was related to the PSMM in both sexes, with β coefficients of 0.261 (95% CI 0.006-0.516; P = 0.045) in men and 0.179 (95% CI 0.029-0.328; P = 0.019) in women. By-obesity status analysis showed that urine pH was related to the PSMM in the body mass index <27 group with a β coefficient of 0.284 (95% CI 0.101-0.466; P = 0.002) after full adjustment. However, for the body mass index ≥27 group, there was no significant relationship between urine pH and the PSMM (P > 0.05).

CONCLUSION

The results showed the impacts of urine pH levels on skeletal muscle mass in both sexes and non-obese populations. Due to its easily accessible and economical characteristics, urine analysis is a convenient way to approach patients with low skeletal muscle mass and predict sarcopenia. Geriatr Gerontol Int 2021; 21: 944-949.

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.