Incidence and treatment of splanchnic vein thrombosis in patients with acute pancreatitis: A systematic review and meta-analysis.

BACKGROUND AND AIM: This meta-analysis aimed to estimate the incidence of splanchnic vein thrombosis (SVT) in patients with acute pancreatitis and assess the effects of therapeutic anticoagulation. METHODS: Systematic searches of the Medline, Embase, and Cochrane databases were undertaken to identify studies reporting the incidence and outcomes associated with SVT in patients with acute pancreatitis. The pooled incidence, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random effects model. PROSPERO database registration no. CRD 42021230912. RESULTS: Only 18 of the 238 studies identified met the inclusion criteria. Of the 943 patients who had SVT, 264 (28.0%) received anticoagulation. The pooled incidence of SVT at first presentation of acute pancreatitis was 15% (95% CI 5 to 26%), but was 17% (95% CI 14 to 20%) in all studies. Recanalization was more likely to occur in the anticoagulation-treated than in the untreated group (OR 0.51, 95% CI 0.31 to 0.83, P = 0.007). There were no differences in hemorrhagic complications (OR 2.27, 95% CI 0.81 to 6.37, P = 0.12) or overall mortality (OR 2.37, 95% CI 0.86 to 6.52, P = 0.10) in relation to the use of anticoagulation. The overall incidence of portal hypertension in patients was 60% (95% CI 55 to 65%). However, it was not possible to determine the incidence in each group. CONCLUSIONS: The incidence of SVT in patients with acute pancreatitis is significant. Treatment with anticoagulants improved the odds of recanalization but did not increase the risk of hemorrhagic complications or overall mortality.

In vivo confocal microscopy features and clinicohistological correlation of limbal nerve corpuscles.

AIMS: To describe the in vivo confocal microscopy (IVCM) features of human limbal nerve corpuscles (LNCs) and correlate these with the histological features. METHODS: We examined 40 eyes of 29 healthy living subjects (17 female, 12 male; mean age=47.6) by IVCM. Four limbal quadrants were scanned through all epithelial layers and stroma to identify the LNCs and associated nerves. Ten fresh normal human corneoscleral discs from five deceased patients with a mean age of 67 years and 17 eye-bank corneoscleral rims with a mean age of 57.6 years were stained as whole mounts by the acetylcholinesterase (AChE) method to demonstrate LNCs and corneal nerves. Stained tissue was scanned in multiple layers with the NanoZoomer digital pathology microscope. The in vivo results were correlated to the histological findings. RESULTS: On IVCM, LNCs were identified in 65% of the eyes studied and were mainly (84%) located in the inferior or superior limbal regions. They appeared either as bright (hyper-reflective) round or oval single structures within the hyporeflective, relatively acellular fibrous core of the palisades or were clustered in groups, often located anterior to the palisades of Vogt. They measured 36 µm in largest diameter (range 20-56 µm). The in vivo features were consistent with the histology, which showed LNCs as strongly AChE positive round or oval structures. CONCLUSION: The strong correlation with histology will enable use of IVCM to study LNCs in normal and disease conditions.

Nerve terminals at the human corneoscleral limbus.

AIMS: To demonstrate and characterise distinct subepithelial compact nerve endings (CNE) at the human corneoscleral limbus. METHODS: Ten fresh human donor corneoscleral discs (mean age, 67 years) and 26 organ-cultured corneoscleral rims (mean age, 59 years) were studied. All samples were subjected to enzyme histochemical staining related to endogenous acetylcholinesterase present in nerve tissue and H&E staining. Whole-mount en face imaging with NanoZoomer digital pathology microscope and serial cross-section imaging with light microscope were undertaken. RESULTS: Nerves entering the corneoscleral limbus and peripheral cornea terminate under the epithelium as enlarged multiloculated and multinucleated ovoid structures within a 2 mm zone. They are closely associated with the rete pegs of the limbal palisades and the limbal epithelial crypts, often located within characteristic stromal invaginations of these structures. Their numbers ranged from 70 to 300 per corneoscleral rim. The size ranged from 20 to 100 µm. They had one or more nerve connections and were interconnected to other similar endings and to the limbal nerve plexus. CONCLUSION: Human corneoscleral limbus demonstrates a population of nerve terminals resembling CNE with distinct morphological features. They are closely associated with the limbal stem cell niches, suggesting a potential contribution to the niche environment.