Hemodynamic and oxygen-metabolic responses of the awake mouse brain to hypercapnia revealed by multi-parametric photoacoustic microscopy

A widely used cerebrovascular stimulus and common pathophysiologic condition, hypercapnia is of great interest in brain research. However, it remains controversial how hypercapnia affects brain hemodynamics and energy metabolism. By using multi-parametric photoacoustic microscopy, the multifaceted responses of the awake mouse brain to different levels of hypercapnia are investigated. Our results show significant and vessel type-dependent increases of the vessel diameter and blood flow in response to the hypercapnic challenges, along with a decrease in oxygen extraction fraction due to elevated venous blood oxygenation. Interestingly, the increased blood flow and decreased oxygen extraction are not commensurate with each other, which leads to reduced cerebral oxygen metabolism. Further, time-lapse imaging over 2-hour chronic hypercapnic challenges reveals that the structural, functional, and metabolic changes induced by severe hypercapnia (10% CO2) are not only more pronounced but more enduring than those induced by mild hypercapnia (5% CO2), indicating that the extent of brain's compensatory response to chronic hypercapnia is inversely related to the severity of the challenge. Offering quantitative, dynamic, and CO2 level-dependent insights into the hemodynamic and metabolic responses of the brain to hypercapnia, these findings might provide useful guidance to the application of hypercapnia in brain research.

Promoting the get healthy information and coaching service (GHS) in Australian-Chinese communities: facilitators and barriers

Obesity and being overweight are major public health concerns that health coaching can assist people to manage through encouraging self-management and behaviour change. The Get Healthy Information and Coaching Service (GHS) is a telephone health coaching service in Australia that has effectively improved the health of the general population but has had less participation of culturally and linguistically diverse (CALD) populations. The Chinese population is the largest migrant group in Australia with increased risk of diabetes but had reduced access to the GHS program due to communication barriers. The GHS developed a pilot program for Chinese (Mandarin and Cantonese-speaking) communities using bilingual coaches and translated material to address these barriers. Qualitative research was undertaken with Chinese stakeholders (14 interviews) and 11 program participants from the group which had completed the program (2 focus groups in Mandarin and Cantonese) to understand their experiences and the success of promotional activities. This research does not contain the experiences of the people that withdrew from the program. The bilingual program was culturally and linguistically appropriate and addressed risk factors for chronic conditions. Participants formed positive relationships with bilingual coaches who they preferred to interpreters. They felt the program promoted healthy eating, weight and physical activity. Although Chinese stakeholders had concerns about participants' ability to goal set, participants said they met their health goals and were committed to the GHS program. Strategies to enhance the program included promoting the bilingual GHS to the communities and stakeholders. Factors to consider beyond language in adapting the program to the Australian Chinese communities include meeting the heterogenous needs of the older population, ensuring community engagement and addressing cultural beliefs and practices.

Effect of high-flow vs. low-flow nasal plus mouthguard oxygen therapy on hypoxaemia during sedation: a multicentre randomised controlled trial

Whether high-flow vs. low-flow nasal oxygen reduces hypoxaemia for sedation during endoscopic retrograde cholangiopancreatography is currently unknown. In this multicentre trial, 132 patients ASA physical status 3 or higher, BMI > 30 kg.m^-2 or with known or suspected obstructive sleep apnoea were randomly allocated to high-flow nasal oxygen up to 60 l.min^-1 at 100% F_I O₂ or low-flow nasal oxygen at 4 l.min^-1 . The low-flow nasal oxygen group also received oxygen at 4 l.min^-1 through an oxygenating mouthguard, totalling 8 l.min^-1 . Primary outcome was hypoxaemia, defined as S_p O₂ < 90% regardless of duration. Hypoxaemia occurred in 7.7% (5/65) of patients with high-flow and 9.1% (6/66) with low-flow nasal oxygen (percentage point difference -1.4%, 95%CI -10.9 to 8.0; p = 0.77). Between the groups, there were no significant differences in frequency of hypoxaemic episodes; lowest S_p O₂ ; peak transcutaneous carbon dioxide; hypercarbia (transcutaneous carbon dioxide > 2.66 kPa from baseline); requirement of chin lift/jaw thrust; nasopharyngeal airway insertion; bag-mask ventilation; or tracheal intubation. Following adjustment for duration of the procedure, the primary outcome remained non-significant. In high-risk patients undergoing endoscopic retrograde cholangiopancreatography, oxygen therapy with high-flow nasal oxygen did not reduce the rate of hypoxaemia, hypercarbia or the need for airway interventions, compared with combined oral and nasal low-flow oxygen.

Safety of sofosbuvir-based regimens after liver transplantation: longitudinal assessment of renal function in the prospective ANRS CO23 CUPILT study

BACKGROUND

In liver transplant recipients with hepatitis C virus recurrence, there is concern about renal safety of sofosbuvir-based regimens. Changes in serum creatinine or in the estimated glomerular filtration rate (eGFR) under treatment are used to look for possible renal toxicity. However, serum creatinine and eGFR are highly variable.

AIM

To analyse renal function trajectory with numerous assays of serum creatinine over a long period of time.

METHODS

In a multicentre cohort of 139 patients, the eGFR was obtained from serum creatinine using the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation. Slopes of eGFR were defined as a change in eGFR during a period divided by time. Pre-treatment, on-treatment and post-treatment periods were 9 months, 3-9 months and 4.5 months. Interactions between eGFR slopes and the pre-treatment eGFR, use of ribavirin or mycophenolate mofetil, and stage of fibrosis were addressed. On-treatment eGFR slopes were separated in tertiles. Pre- and post-treatment eGFR slopes were compared globally and according to tertiles.

RESULTS

The post-treatment eGFR slope was significantly better than pre-treatment eGFR slope (+0.18 (IQR -0.76 to +1.32) vs -0.11 (IQR -1.01 to +0.73) mL/min/1.73 m² /month, P = 0.03) independently of the pre-treatment eGFR (P = 0.99), ribavirin administration (P = 0.26), mycophenolate mofetil administration (P = 0.51) and stage of fibrosis (F3 and F4 vs lower stages, P = 0.18; F4 vs lower stages, P = 0.08; F4 Child-Pugh B and C vs lower stages, P = 0.38). Tertiles of on-treatment eGFR slopes were -1.71 (IQR -2.54 to -1.48), -0.78 (IQR -1.03 to -0.36) and +0.75 (IQR +0.28 to +1.47) mL/min/1.73 m² /month. Pre- and post-treatment eGFR slopes were not significantly different according to tertiles (respectively, P = 0.34, 0.08, 0.73).

CONCLUSION

The eGFR varies during treatment and gives a confusing picture of the renal safety of sofosbuvir-based regimens. In contrast, longitudinal assessment of the eGFR shows a rising trajectory over longer time, meaning that these therapies are safe for the kidneys in our cohort of liver transplant recipients.

Screening for therapeutic trials and treatment indication in clinical practice: MACK-3, a new blood test for the diagnosis of fibrotic NASH

BACKGROUND

The composite histological endpoint comprising nonalcoholic steatohepatitis (NASH) and NAFLD activity score ≥4 and advanced fibrosis (F ≥ 2) ("fibrotic NASH") is becoming an important diagnostic target in NAFLD: it is currently used to select patients for inclusion in phase III therapeutic trials and will ultimately be used to indicate treatment in clinical practice once the new drugs are approved.

AIM

To develop a new blood test specifically dedicated for this new diagnostic target of interest.

METHODS

Eight Hundred and forty-six biopsy-proven NAFLD patients from three centres (Angers, Nice, Antwerp) were randomised into derivation and validation sets.

RESULTS

The blood fibrosis tests BARD, NFS and FIB4 had poor accuracy for fibrotic NASH with respective AUROC: 0.566 ± 0.023, 0.654 ± 0.023, 0.732 ± 0.021. In the derivation set, fibrotic NASH was independently predicted by AST, HOMA and CK18; all three were combined in the new blood test MACK-3 (hoMa, Ast, CK18) for which 90% sensitivity and 95% specificity cut-offs were calculated. In the validation set, MACK-3 had a significantly higher AUROC (0.847 ± 0.030, P ≤ 0.002) than blood fibrosis tests. Using liver biopsy in the grey zone between the two cut-offs (36.0% of the patients), MACK-3 provided excellent accuracy for the diagnosis of fibrotic NASH with 93.3% well-classified patients, sensitivity: 90.0%, specificity: 94.2%, positive predictive value: 81.8% and negative predictive value: 97.0%.

CONCLUSION

The new blood test MACK-3 accurately diagnoses fibrotic NASH. This new test will facilitate patient screening and inclusion in NAFLD therapeutic trials and will enable the identification of patients who will benefit from the treatments once approved.