Genetic vulnerability to Crohn's disease reveals a spatially resolved epithelial restitution program

Effective tissue repair requires coordinated intercellular communication to sense damage, remodel the tissue, and restore function. Here, we dissected the healing response in the intestinal mucosa by mapping intercellular communication at single-cell resolution and integrating with spatial transcriptomics. We demonstrated that a risk variant for Crohn's disease, hepatocyte growth factor activator (HGFAC) Arg509His (R509H), disrupted a damage-sensing pathway connecting the coagulation cascade to growth factors that drive the differentiation of wound-associated epithelial (WAE) cells and production of a localized retinoic acid (RA) gradient to promote fibroblast-mediated tissue remodeling. Specifically, we showed that HGFAC R509H was activated by thrombin protease activity but exhibited impaired proteolytic activation of the growth factor macrophage-stimulating protein (MSP). In Hgfac R509H mice, reduced MSP activation in response to wounding of the colon resulted in impaired WAE cell induction and delayed healing. Through integration of single-cell transcriptomics and spatial transcriptomics, we demonstrated that WAE cells generated RA in a spatially restricted region of the wound site and that mucosal fibroblasts responded to this signal by producing extracellular matrix and growth factors. We further dissected this WAE cell-fibroblast signaling circuit in vitro using a genetically tractable organoid coculture model. Collectively, these studies exploited a genetic perturbation associated with human disease to disrupt a fundamental biological process and then reconstructed a spatially resolved mechanistic model of tissue healing.

The incidence and outcomes of high-risk acute coronary syndromes in Western Cape Province, South Africa: A prospective cohort study

BACKGROUND

Tygerberg Hospital (TBH) is a tertiary-level hospital in Western Cape Province, South Africa, that provides healthcare to a large low- to middle-income population with services including centralised advanced cardiac care. Acute coronary syndrome (ACS) remains an important cause of death in the region despite a high burden of communicable diseases, including HIV.

OBJECTIVES

To describe the incidence of ST-elevation myocardial infarction (STEMI) and high-risk non-ST-elevation ACS (HR-NSTEACS) in the TBH referral network, describe the in-hospital and 30-day mortality of these patients, and identify important high-risk population characteristics.

METHODS

The Tygerberg Acute Coronary Syndrome Registry database is an ongoing prospective study that enrols all STEMI and HR-NSTEACS patients in the TBH referral network. All patients aged >18 years presenting with STEMI or HR-NSTEACS were treated in accordance with current European Society of Cardiology guidelines and were included prospectively over a 9-month surveillance period. A waiver of consent was granted to include patients who died before giving informed consent. Data collected included a demographic profile, risk factors for cardiovascular disease, in-hospital therapy and 30-day mortality.

RESULTS

A total of 586 patients were enrolled, with a male predominance (64.5%) and incidence rates of STEMI and HR-NSTEACS of 14.7 per 100 000 and 15.6 per 100 000, respectively. The mean patient age was 58 years, and STEMI patients tended to be younger than HR-NSTEACS patients (56 v. 58 years; p=0.01). Cardiovascular risk factors were prevalent overall, but hypertension (79.8% v. 68.3%; p<0.01) and pre-existing IHD (29.1% v. 7.0%; p=0.03) were more prevalent in the HR-NSTEACS group. HIV was present in 12.6% of patients tested, similar to the background population rate. The overall 30-day all-cause mortality rate was 6.1%, with an in-hospital mortality rate of 3.9%. The 30-day mortality rates were similar for STEMI (1.8%) and HR-NSTEACS (2.6%) (p=0.75). HIV did not affect mortality rates.

CONCLUSION

Use of a guideline-based approach to treating ACS in a low- to middle-income country setting yields mortality rates comparable to those in high-income countries. However, the lower-than-expected incidence rates of both STEMI and HR-NSTEACS in a relatively young population with a high prevalence of traditional cardiovascular risk factors, and a relatively high proportion of STEMI, suggest potential under-recording of ischaemic heart disease in the region. The rate and outcomes of coronary artery disease (CAD) in people living with HIV were similar to those in people without HIV, suggesting that traditional risk factors still drive CAD outcomes in the region.

Lymphangiogenesis Guidance Mechanisms and Therapeutic Implications in Pathological States of the Cornea

Corneal lymphangiogenesis is one component of the neovascularization observed in several inflammatory pathologies of the cornea including dry eye disease and corneal graft rejection. Following injury, corneal (lymph)angiogenic privilege is impaired, allowing ingrowth of blood and lymphatic vessels into the previously avascular cornea. While the mechanisms underlying pathological corneal hemangiogenesis have been well described, knowledge of the lymphangiogenesis guidance mechanisms in the cornea is relatively scarce. Various signaling pathways are involved in lymphangiogenesis guidance in general, each influencing one or multiple stages of lymphatic vessel development. Most endogenous factors that guide corneal lymphatic vessel growth or regression act via the vascular endothelial growth factor C signaling pathway, a central regulator of lymphangiogenesis. Several exogenous factors have recently been repurposed and shown to regulate corneal lymphangiogenesis, uncovering unique signaling pathways not previously known to influence lymphatic vessel guidance. A strong understanding of the relevant lymphangiogenesis guidance mechanisms can facilitate the development of targeted anti-lymphangiogenic therapeutics for corneal pathologies. In this review, we examine the current knowledge of lymphatic guidance cues, their regulation of inflammatory states in the cornea, and recently discovered anti-lymphangiogenic therapeutic modalities.

pH sensing controls tissue inflammation by modulating cellular metabolism and endo-lysosomal function of immune cells

Extracellular acidification occurs in inflamed tissue and the tumor microenvironment; however, a systematic study on how pH sensing contributes to tissue homeostasis is lacking. In the present study, we examine cell type-specific roles of the pH sensor G protein-coupled receptor 65 (GPR65) and its inflammatory disease-associated Ile231Leu-coding variant in inflammation control. GPR65 Ile231Leu knock-in mice are highly susceptible to both bacterial infection-induced and T cell-driven colitis. Mechanistically, GPR65 Ile231Leu elicits a cytokine imbalance through impaired helper type 17 T cell (TH17 cell) and TH22 cell differentiation and interleukin (IL)-22 production in association with altered cellular metabolism controlled through the cAMP-CREB-DGAT1 axis. In dendritic cells, GPR65 Ile231Leu elevates IL-12 and IL-23 release at acidic pH and alters endo-lysosomal fusion and degradation capacity, resulting in enhanced antigen presentation. The present study highlights GPR65 Ile231Leu as a multistep risk factor in intestinal inflammation and illuminates a mechanism by which pH sensing controls inflammatory circuits and tissue homeostasis.

Echocardiographic features of infective endocarditis in South Africa: A prospective cohort study

BACKGROUND

Historically, infective endocarditis (IE) in South Africa (SA) was associated with the viridans group of streptococci affecting patients with underlying rheumatic heart disease (RHD). A changing IE bacteriological profile raises the question of whether the profile of underlying valvular abnormality has changed.

OBJECTIVES

To investigate the prevalence of underlying structural valve abnormalities and their aetiologies associated with IE in SA, and describe the typical imaging findings.

METHODS

The Tygerberg Endocarditis Cohort study prospectively enrolled patients with IE between November 2019 and April 2021. Patients underwent detailed transthoracic and transoesophageal echocardiography to assess their underlying cardiac and valvular structure.

RESULTS

Among 71 patients included, a predisposing endocardial abnormality was detected in 49.3%, with RHD the most common single identifiable aetiology (16.9%). The in-hospital mortality rate was similar in patients with and without a predisposing endocardial abnormality (20% v. 16.7%; p=0.72), as was the rate of embolic events (20% v. 27.2%; p=0.58). Significantly more patients with a predisposing endocardial abnormality had an indication for surgery (94.3% v. 69.4%; p&lt;0.01). The viridans group of streptococci was more prevalent in patients with a predisposing endocardial abnormality (25.7% v. 2.7%; p&lt;0.01). Left-sided linear vegetation size &gt;10 mm was associated with an increased risk of in-hospital mortality (24% v. 5%; p=0.05).

CONCLUSION

We observed a marked decrease in the prevalence of RHD in this cohort of patients with IE. The viridans group of streptococci was an uncommon cause of IE in patients with no predisposing endocardial abnormality detected. The presence of a predisposing endocardial abnormality was not associated with an increased risk of in-hospital mortality or embolic events. Linear vegetation length &gt;10 mm was associated with an increased risk of in-hospital mortality in patients with left-sided IE.

P6518Radial artery dilatation to improve access and lower complication rates during coronary angiography (RADIAL): a randomized controlled trial

Background

Transradial catheterization has become the preferred access site for coronary angiography. The transradial approach is however not without challenges and complications. Cannulation is technically challenging and may require multiple cannulation attempts or access may fail. Local access site complications may occur postprocedurally.

Purpose

To explore the use of prolonged occlusion flow mediated dilatation (PO-FMD) to dilate the radial artery prior to cannulation to reduce puncture attempts, increase cannulation success and reduce access site complications in transradial coronary angiography.

Methods

1156 patients undergoing transradial coronary angiography were randomized into PO-FMD and sham PO-FMD groups. PO-FMD was achieved by a 10 minute inflation of a blood pressure cuff on the arm to above systolic pressure, followed by deflation with resultant radial artery dilation. In the sham PO-FMD group the cuff was not inflated. The operators were blinded to the intervention.

Results

580 patients were randomized to the sham PO-FMD group and 576 to the PO-FMD group. The number of puncture attempts were reduced with the use of PO-FMD, with a median number of attempts of 1 in the PO-FMD group and 2 in the sham PO-FMD group (p<0.001). Cannulation failure was reduced with PO-FMD FMD with cannulation failure rates of 2.7% in the PO-FMD group and 5.8% in the sham PO-FMD group (p=0.01). Radial artery pulsation loss (RAPL) was reduced with PO-FMD with 1.4% in the PO-FMD group and 3.8% in the sham PO-FMD group (p=0.02).

Conclusion

PO-FMD decreases puncture attempts, reduces cannulation failure rates and decreases RAPL during transradial coronary angiography.

Clomiphene citrate ovulation induction in combination with a timed intrauterine insemination: the value of urinary luteinizing hormone versus human chorionic gonadotropin timing

OBJECTIVE

To evaluate the clinical pregnancy rates (PRs) in anovulatory, male factor, and unexplained infertility using clomiphene citrate (CC) with an IUI and to evaluate the difference in PRs between urinary LH testing and hCG administration for timing of the IUI.

DESIGN

Retrospective clinical study.

SETTING

Academic, tertiary care fertility center.

PATIENT(S)

One hundred thirty-eight couples (432 cycles) undergoing IUI with CC ovulation induction as a treatment for unexplained, anovulatory, or male factor infertility were selected.

INTERVENTION(S)

All women with unexplained or male factor infertility received CC at a dose of 50 mg/d, and those with anovulation received CC at a dose ranging from 50 to 200 mg/d. All women in the study received a single IUI either the morning after a urinary LH surge or 36 to 38 hours after an evening hCG injection.

MAIN OUTCOME MEASURE(S)

Clinical PR.

RESULT(S)

There were no differences in the clinical PRs between LH testing or hCG administration in any of the three groups. Clinical PRs were extremely low in the male factor infertility group regardless of the timing used.

CONCLUSION(S)

These data suggest that the success of IUI with CC is not dependent on the method used to establish the timing for the IUI. In couples undergoing IUI with CC, the use of urinary LH testing may result in lower costs by reducing patient visits and the midcycle ultrasound.

Simultaneous transplantation of isolated hepatocytes reduces rejection of small bowel allografts and improves survival in the rat

Hepatocytes transplanted some days prior to vascularized allografts were shown to have the potential to prolong allograft survival in the rat. In the present study, hepatocytes and small bowel allografts were transplanted simultaneously in a Lewis (donor)-Brown Norway (recipient) rat model. 8-15 x 10(6) liver cells were injected into the spleen of small bowel recipients. The administration of at least 10 mg cyclosporine A (CyA)/kg over 3 days was necessary to prevent early rejection of hepatocytes. In groups simultaneously receiving hepatocytes, small bowel grafts and 10 mg CyA/kg over 3 days, a significant mitigation of rejection and a prolongation of survival was achieved, compared to groups receiving solely small bowel grafts and 10 mg CyA/kg over 3 days. We conclude that simultaneously transplanted hepatocytes exert a protective effect on a grafted organ from the same donor, provided that early rejection of hepatocytes is prevented by sufficient immunosuppression.

Hepatocellular transplantation into the lung in chronic liver failure following bile duct obstruction in the rat

Injection of hepatocytes or cell-free supernatant into the lung was able to prevent death from surgically induced fulminant hepatic failure in the rat in over 90% and 53% of subjects, respectively. The aim of this study was to investigate whether this technique can be applied in chronic liver failure. Chronic liver failure was induced in Lewis rats by ligation and transection of the common bile duct, which led to cirrhosis after 3-5 wk in all animals. Four groups of animals were formed: group 1 (n = 5), normal rats, serving as control; group 2 (n = 15), cirrhotic rats, no further treatment; group 3 (n = 14), hepatocyte transplantation by injection of cell suspension transcutaneously into the right lung of cirrhotic animals four wk after bile duct ligation; group 4 (n = 17), injection of 1 mL cell-free supernatant intravenously at two-day intervals, starting 4 wk after ligation. Liver function tests, prothrombin time and serum protein levels were measured weekly before and every two days after transplantation. In group 2 all animals had died 56 (49-69) days after ligation. Survival in groups 3 and 4 was similar: all rats had died from liver failure 61 (51-72) and 60 (49-76) days following bile duct ligation. Survival rates and laboratory investigations showed no significant differences between treated and untreated cirrhotic animals. These data suggest that hepatocyte transplantation into the lung as well as supernatant injection do not have any significant effect on chronic hepatic failure, at least in the rat model.