Bidirectional Relationship Between Reduced Blood pH and Acute Pancreatitis: A Translational Study of Their Noxious Combination

Ammonium chloride-induced hypothermia is attenuated by transient receptor potential channel vanilloid-1, but augmented by ankyrin-1 in rodents

AIMS

Systemic administration of ammonium chloride (NH4Cl), an acidifying agent used in human patients and experimental conditions, causes hypothermia in mice, however, the mechanisms of the thermoregulatory response to NH4Cl and whether it develops in other species remained unknown.

MAIN METHODS

We studied body temperature (Tb) changes in rats and mice induced by intraperitoneal administration of NH4Cl after blockade of transient receptor potential vanilloid-1 (TRPV1) or ankyrin-1 (TRPA1) channels.

KEY FINDINGS

In rats, NH4Cl decreased Tb by 0.4-0.8°C (p < 0.05). The NH4Cl-induced hypothermia also developed in Trpv1 knockout (Trpv1-/-) and wild-type (Trpv1+/+) mice, however, the Tb drop was exaggerated in Trpv1-/- mice compared to Trpv1+/+ controls with maximal decreases of 4.0 vs. 2.1°C, respectively (p < 0.05). Pharmacological blockade of TRPV1 channels with AMG 517 augmented the hypothermic response to NH4Cl in genetically unmodified mice and rats (p < 0.05 for both). In contrast, when NH4Cl was infused to mice genetically lacking the TRPA1 channel, the hypothermic response was significantly attenuated compared to wild-type controls with maximal mean Tb difference of 1.0°C between the genotypes (p = 0.008). Pretreatment of rats with a TRPA1 antagonist (A967079) also attenuated the NH4Cl-induced Tb drop with a maximal difference of 0.7°C between the pretreatment groups (p = 0.003).

SIGNIFICANCE

TRPV1 channels limit, whereas TRPA1 channels exaggerate the development of NH4Cl-induced hypothermia in rats and mice, but other mechanisms are also involved. Our results warrant for regular Tb control and careful consideration of NH4Cl treatment in patients with TRPA1 and TRPV1 channel dysfunctions.

Serum Bicarbonate Deficiency in Dogs with Acute and Chronic Kidney Disease

Serum bicarbonate deficiency is a disorder frequently found in human patients with acute (AKI) and chronic (CKD) kidney disease, due to abnormalities in kidney generation and reabsorption of bicarbonate. Although alkali supplementation is usually performed in both humans and veterinary CKD patients, data regarding the frequency of bicarbonate disorders in AKI and CKD dogs are scarce. The aim of the present study is to assess the frequency and the severity of bicarbonate deficiency of dogs affected by AKI, acute chronic kidney disease (ACKD), and CKD, and to investigate its possible association with the IRIS grade/stage as well as with disorders of calcium phosphate metabolism. A retrospective evaluation of the serum biochemical panels of all dogs with diagnoses of AKI, ACKD, and CKD referred to the nephrology and urology service of the Veterinary Teaching Hospital of the University of Pisa, between January 2014 and January 2022, was performed. Bicarbonate deficiency was defined as serum bicarbonate < 22 mmol/L and classified as moderate (between 18 and 22 mmol/L) or severe (<18 mmol/L). Serum bicarbonate deficiency was found in 397/521 dogs (76%), of which 142/397 (36%) showed moderate deficiency, and 255/397 (64%) severe deficiency. Dogs with AKI and ACKD showed a significantly higher frequency of bicarbonate deficiency (p = 0.004) and severe forms compared to CKD dogs (p = 0.02). In AKI and ACKD dogs, a negative linear correlation was found between serum bicarbonate and serum creatinine, urea, and phosphate. The frequency of bicarbonate deficiency was higher in the later stages of the disease in both AKI (p = 0.01), ACKD (p = 0.0003), and CKD dogs (p = 0.009). Dogs with serum CaxP ≥ 70 mg²/dL² showed a higher frequency of bicarbonate deficiency (p = 0.01) and showed severe forms (p = 0.01) compared to dogs with CaxP < 70 mg²/dL². Serum bicarbonate deficiency seems to be a very frequent disorder in both AKI, ACKD, and CKD dogs, with an increasing frequency and severity in more advanced stages of kidney disease. The higher frequency and severity of bicarbonate deficiency in AKI and ACKD may be caused by a more severe and sudden loss of kidney function, or extra-renal factors. Finally, the association between frequency and severity of bicarbonate deficiency and abnormal CaxP may suggest a potential connection between metabolic acidosis and bone mineral disorders.

A Rapid Prognostic Score Based on Bedside Arterial Blood Gas Analysis (ABG) Established for Predicting 60-Day Adverse Outcomes in Patients with Acute Pancreatitis in the Emergency Department

Objective

To establish a rapid and concise prognosis scoring system for pancreatitis in the emergency department based on bedside arterial blood gas analysis (ABG).

Methods

A single-center, retrospective cohort study was used to establish the new scoring system, and a validation group was used to verify it. The primary endpoint was 60-day death, and secondary endpoints were 28-day death, admission to the intensive care unit (AICU), requirement for mechanical ventilation (MV) and persistent organ failure (POF). Receiver operating characteristic (ROC) curves was drawn to validate the predictive value of the new scoring system. The performance of the new scoring system was compared with that of conventional predictive scoring.

Results

443 patients were in the derivation group and 217 patients in the validation group, of which 27 and 25 died during follow-up. A total of 443 patients in the derivation group, 27 of whom died during the follow-up period. Multivariate regression analysis showed that mental status, hematocrit (HCT), base excess (BE) and Serum ionic calcium (Ca²⁺) were independent risk factors for 60-day mortality of pancreatitis, and they were used to create a new scoring system (MHBC). In the derivation and validation, the ability of MHBC (AUC= 0.922, 0.773, respectively) to predict 60-day mortality from pancreatitis was no less than that of APACHE II (AUC= 0.838, 0.748, respectively) and BISAP (AUC= 0.791, 0.750, respectively), while, MHBC is more quickly and concisely than APACHE II and BISAP. Compared with MHBC less than or equal to 2, when MHBC is greater than 2, the 28-day mortality, 60-day mortality and the incidence of AICU, MV and POF increased significantly (P <0.001).

Conclusion

The MHBC can quickly and concisely evaluate the 60-day mortality, 28-day mortality, and the incidence of AICU, MV and POF of patients with acute pancreatitis in the emergency department.

Calcium and pH value might predict persistent renal failure in acute pancreatitis in the early phase

OBJECTIVES

Persistent renal failure (PRF) increases morbidity and mortality in acute pancreatitis (AP). Traditional scoring systems achieve good diagnostic value of AP but not PRF alone. Our study aimed to determine PRF predictors in AP patients for early intervention in the disease development.

METHODS

In the prospective observational study, we consecutively recruited AP patients from October 2013 to October 2016. Complete clinical characteristics on admission were collected. The 2012 revision of the Atlanta classification diagnosed AP, and the Modified Marshall scoring system defined organ failures. We used univariate and multivariate analyses to select risk factors, and plotted survival curves of different groups and ROC curves of parameters to analyze PRF predictors in AP.

RESULTS

A total of 29 AP patients with PRF and 280 AP patients without PRF were included. Severity scoring and ICU admission rate were higher in the former group. The PRF group's mortality was 10-fold higher than without PRF (20.7% versus 2.1%, p < .001). Most relevant kidney metabolism indicators and excretion have significant differences (p < .05) between the two groups. Serum calcium (Ca) and pH value (pH) were independent risk factors of PRF (p < .05). ROC curve analysis indicated Ca and pH might predict PRF in AP with areas under the curves (AUCs) of 0.758 and 0.809.

CONCLUSIONS

AP patients with PRF had higher morbidity and mortality rate. Our study showed that Ca < 1.94 mmol/L and pH < 7.37 when patients on admission could be used to predict PRF in AP.

Kynurenic Acid and Its Analogue SZR-72 Ameliorate the Severity of Experimental Acute Necrotizing Pancreatitis

The pathophysiology of acute pancreatitis (AP) is not well understood, and the disease does not have specific therapy. Tryptophan metabolite L-kynurenic acid (KYNA) and its synthetic analogue SZR-72 are antagonists of the N-methyl-D-aspartate receptor (NMDAR) and have immune modulatory roles in several inflammatory diseases. Our aims were to investigate the effects of KYNA and SZR-72 on experimental AP and to reveal their possible mode of action. AP was induced by intraperitoneal (i.p.) injection of L-ornithine-HCl (LO) in SPRD rats. Animals were pretreated with 75-300 mg/kg KYNA or SZR-72. Control animals were injected with physiological saline instead of LO, KYNA and/or SZR-72. Laboratory and histological parameters, as well as pancreatic and systemic circulation were measured to evaluate AP severity. Pancreatic heat shock protein-72 and IL-1β were measured by western blot and ELISA, respectively. Pancreatic expression of NMDAR1 was investigated by RT-PCR and immunohistochemistry. Viability of isolated pancreatic acinar cells in response to LO, KYNA, SZR-72 and/or NMDA administration was assessed by propidium-iodide assay. The effects of LO and/or SZR-72 on neutrophil granulocyte function was also studied. Almost all investigated laboratory and histological parameters of AP were significantly reduced by administration of 300 mg/kg KYNA or SZR-72, whereas the 150 mg/kg or 75 mg/kg doses were less or not effective, respectively. The decreased pancreatic microcirculation was also improved in the AP groups treated with 300 mg/kg KYNA or SZR-72. Interestingly, pancreatic heat shock protein-72 expression was significantly increased by administration of SZR-72, KYNA and/or LO. mRNA and protein expression of NMDAR1 was detected in pancreatic tissue. LO treatment caused acinar cell toxicity which was reversed by 250 µM KYNA or SZR-72. Treatment of acini with NMDA (25, 250, 2000 µM) did not influence the effects of KYNA or SZR-72. Moreover, SZR-72 reduced LO-induced H₂O₂ production of neutrophil granulocytes. KYNA and SZR-72 have dose-dependent protective effects on LO-induced AP or acinar toxicity which seem to be independent of pancreatic NMDA receptors. Furthermore, SZR-72 treatment suppressed AP-induced activation of neutrophil granulocytes. This study suggests that administration of KYNA and its derivative could be beneficial in AP.

Recent Advances in Electrochemical and Optical Sensors for Detecting Tryptophan and Melatonin

Tryptophan and melatonin are pleiotropic molecules, each capable of influencing several cellular, biochemical, and physiological responses. Therefore, sensitive detection of tryptophan and melatonin in pharmaceutical and human samples is crucial for human well-being. Mass spectrometry, high-performance liquid chromatography, and capillary electrophoresis are common methods for both tryptophan and melatonin analysis; however, these methods require copious amounts of time, money, and manpower. Novel electrochemical and optical detection tools have been subjects of intensive research due to their ability to offer a better signal-to-noise ratio, high specificity, ultra-sensitivity, and wide dynamic range. Recently, researchers have designed sensitive and selective electrochemical and optical platforms by using new surface modifications, microfabrication techniques, and the decoration of diverse nanomaterials with unique properties for the detection of tryptophan and melatonin. However, there is a scarcity of review articles addressing the recent developments in the electrochemical and optical detection of tryptophan and melatonin. Here, we provide a critical and objective review of high-sensitivity tryptophan and melatonin sensors that have been developed over the past six years (2015 onwards). We review the principles, performance, and limitations of these sensors. We also address critical aspects of sensitivity and selectivity, limit and range of detection, fabrication process and time, durability, and biocompatibility. Finally, we discuss challenges related to tryptophan and melatonin detection and present future outlooks.

Combined use of indomethacin and hydration is the best conservative approach for post-ERCP pancreatitis prevention: A network meta-analysis

OBJECTIVES

Post-ERCP pancreatitis (PEP) is a life-threatening complication. Given the lack of a causative treatment for pancreatitis, it is of vital importance to minimize this risk of PEP. Multi-target preventive therapy may be the best choice for PEP prevention as disease development is multifactorial.

AIM

We aimed to assess the efficacy of a combination of indomethacin and hydration - type and amount - for PEP prevention via a network meta-analysis.

METHODS

Through a systematic search in three databases, we searched all randomized controlled trials involving hydration and indomethacin and ranked the PEP preventive efficacy with a Bayesian network meta-analysis using the PRISMA for Network Meta-Analyses (PRISMA-NMA) guideline. The RoB2 tool was used for risk of bias assessment, surface under the cumulative ranking curve (SUCRA) for ranking and PROSPERO for the study protocol [reg. no. CRD42018112698]. We used risk ratios (RR) for dichotomous data with 95% credible intervals (95% CrI).

RESULTS

The quantitative analysis included 7559 patients from 24 randomized controlled trials. Based on the SUCRA values, a combination of lactated Ringer's and indomethacin is more effective than single therapy with a 94% certainty. The percent relative risk ratios estimate preventive efficacy 70-99% higher for combinations than single therapies. Aggressive hydration with indomethacin (SUCRA 100%) is also significantly more effective than all other interventions (percent relative effect 94.3-98.1%).

CONCLUSIONS

A one-hit-on-each-target therapeutic approach is recommended in PEP prevention with an easily accessible combination of indomethacin and aggressive hydration for all average and high-risk patients without contraindication.

Evidence for diagnosis of early chronic pancreatitis after three episodes of acute pancreatitis: a cross-sectional multicentre international study with experimental animal model

Chronic pancreatitis (CP) is an end-stage disease with no specific therapy; therefore, an early diagnosis is of crucial importance. In this study, data from 1315 and 318 patients were analysed from acute pancreatitis (AP) and CP registries, respectively. The population from the AP registry was divided into AP (n = 983), recurrent AP (RAP, n = 270) and CP (n = 62) groups. The prevalence of CP in combination with AP, RAP2, RAP3, RAP4 and RAP5 + was 0%, 1%, 16%, 50% and 47%, respectively, suggesting that three or more episodes of AP is a strong risk factor for CP. Laboratory, imaging and clinical biomarkers highlighted that patients with RAP3 + do not show a significant difference between RAPs and CP. Data from CP registries showed 98% of patients had at least one AP and the average number of episodes was four. We mimicked the human RAPs in a mouse model and found that three or more episodes of AP cause early chronic-like morphological changes in the pancreas. We concluded that three or more attacks of AP with no morphological changes to the pancreas could be considered as early CP (ECP).The new diagnostic criteria for ECP allow the majority of CP patients to be diagnosed earlier. They can be used in hospitals with no additional costs in healthcare.