Reduced circulating FABP2 in patients with moderate to severe COVID-19 may indicate enterocyte functional change rather than cell death

The gut is of importance in the pathology of COVID-19 both as a route of infection, and gut dysfunction influencing the severity of disease. Systemic changes caused by SARS-CoV-2 gut infection include alterations in circulating levels of metabolites, nutrients and microbial products which alter immune and inflammatory responses. Circulating plasma markers for gut inflammation and damage such as zonulin, lipopolysaccharide and β-glycan increase in plasma along with severity of disease. However, Intestinal Fatty Acid Binding Protein / Fatty Acid Binding Protein 2 (I-FABP/FABP2), a widely used biomarker for gut cell death, has paradoxically been shown to be reduced in moderate to severe COVID-19. We also found this pattern in a pilot cohort of mild (n = 18) and moderately severe (n = 19) COVID-19 patients in Milan from March to June 2020. These patients were part of the first phase of COVID-19 in Europe and were therefore all unvaccinated. After exclusion of outliers, patients with more severe vs milder disease showed reduced FABP2 levels (median [IQR]) (124 [368] vs. 274 [558] pg/mL, P < 0.01). A reduction in NMR measured plasma relative lipid-CH3 levels approached significance (median [IQR]) (0.081 [0.011] vs. 0.073 [0.024], P = 0.06). Changes in circulating lipid levels are another feature commonly observed in severe COVID-19 and a weak positive correlation was observed in the more severe group between reduced FABP2 and reduced relative lipid-CH3 and lipid-CH2 levels. FABP2 is a key regulator of enterocyte lipid import, a process which is inhibited by gut SARS-CoV-2 infection. We propose that the reduced circulating FABP2 in moderate to severe COVID-19 is a marker of infected enterocyte functional change rather than gut damage, which could also contribute to the development of hypolipidemia in patients with more severe disease.

Platelet-leucocyte aggregation is augmented in cirrhosis and further increased by platelet transfusion

BACKGROUND

Thrombocytopenia and circulating dysfunctional immune cells are commonly observed in patients with cirrhosis. Platelets may form complexes with neutrophils, monocytes and T cells modulating their function. We recently reported increased frequencies of platelet-complexed neutrophils in cirrhosis with evidence of neutrophil activation upon contact with healthy platelets in vitro. Whether this occurs in vivo following platelet transfusion and contributes to systemic inflammation and endothelial activation is unknown.

AIMS

To characterise platelet-leucocyte aggregation in cirrhosis and to determine whether elective platelet transfusion results in perturbations associated with changes in markers of haemostasis, inflammation or endothelial activation.

METHODS

We collected blood from cirrhotics (n = 19) before and following elective platelet transfusion. We measured platelet-leucocyte aggregation, activation and function, and markers of platelet activation, systemic inflammation and endothelial activation by flow cytometry. Haemostasis was assessed by thromboelastometry and plasma haemostatic proteins.

RESULTS

We observed a 2.5-fold increase in platelet-complexed neutrophils in patients with cirrhosis compared with healthy subjects and twofold more platelets attached per monocyte and T cell. All platelet-complexed leucocytes expressed higher levels of activation markers and platelet-complexed neutrophils had higher resting oxidative burst and phagocytic capacity than their nonplatelet-complexed counterparts (P < 0.001); most pronounced in patients with cirrhosis. Paradoxically, platelet-complexed leucocyte frequency decreased with increasing MELD score. Platelet transfusion increased soluble CD40 ligand (platelet activation marker), the frequency of platelet-complexed monocytes (P < 0.05) and improved haemostatic status.

CONCLUSION

Cirrhotic patients have activated circulating platelet-complexed leucocytes with increased platelet-monocyte aggregation following elective platelet transfusion. Elective platelet transfusion might therefore exacerbate immune dysfunction in cirrhosis.

Review article: the gut microbiome as a therapeutic target in the pathogenesis and treatment of chronic liver disease

BACKGROUND

Mortality from chronic liver disease is rising exponentially. The liver is intimately linked to the gut via the portal vein, and exposure to gut microbiota and their metabolites translocating across the gut lumen may impact upon both the healthy and diseased liver. Modulation of gut microbiota could prove to be a potential therapeutic target.

AIM

To characterise the changes in the gut microbiome that occur in chronic liver disease and to assess the impact of manipulation of the microbiome on the liver.

METHODS

We conducted a PubMed search using search terms including 'microbiome', 'liver' and 'cirrhosis' as well as 'non-alcoholic fatty liver disease', 'steatohepatitis', 'alcohol' and 'primary sclerosing cholangitis'. Relevant articles were also selected from references of articles and review of the ClinicalTrials.gov website.

RESULTS

Reduced bacterial diversity, alcohol sensitivity and the development of gut dysbiosis are seen in several chronic liver diseases, including non-alcoholic fatty liver disease, alcohol-related liver disease and primary sclerosing cholangitis. Perturbations in gut commensals could lead to deficient priming of the immune system predisposing the development of immune-mediated diseases. Furthermore, transfer of stool from an animal with the metabolic syndrome may induce steatosis in a healthy counterpart. Patients with cirrhosis develop dysbiosis, small bowel bacterial overgrowth and increased gut wall permeability, allowing bacterial translocation and uptake of endotoxin inducing hepatic and systemic inflammation.

CONCLUSIONS

Manipulation of the gut microbiota with diet, probiotics or faecal microbiota transplantation to promote the growth of "healthy" bacteria may ameliorate the dysbiosis and alter prognosis.

Polyimides Containing an s-Triazine Ring

A series of new polyimides containing an s-triazine nucleus were prepared via Diels–Alder (DA) intermolecular polymerization of 2,6-bis(2-furanyl methyl imino)-4-ethoxy-1,3,5-triazine with different bis(maleimide) compounds. The DA reaction was carried out in tetrahydrofuran as solvent, as well as in bulk followed by aromatization of poly(tetrahydrophthalimido)-intermediates in the presence of acetic anhydride. All the poly(imino- s-triazine imide)s were characterized by elemental analysis, IR spectral studies and thermogravimetry. Glass fibre reinforced composites were prepared via in situ Diels–Alder intermolecular reaction between 2,6-bis(2-furanyl methyl imino)-4-ethoxy-1,3,5-triazine and different bis(maleimide) compounds without evolution of by-products. The prepared composites were characterized by chemical resistivity and mechanical properties.

Retrospective analysis of the impact of a low glycaemic index diet on hospital stay following coronary artery bypass grafting: a hypothesis

OBJECTIVE

Glucose tolerance and insulin resistance influence medical outcome in subjects with coronary artery disease, these metabolic parameters also influence general perioperative surgical outcome. We hypothesize that glucose tolerance and insulin resistance can be favourably modified by reducing the glycaemic index of the diet.

DESIGN

The present study is a retrospective analysis of a low and high glycaemic index diet on glucose tolerance, insulin resistance and perioperative outcome, as assessed by the length of hospital stay following coronary artery bypass surgery. Thirty-five adults awaiting bypass surgery were randomized, for the 4 weeks prior to surgery, to either a low glycaemic index diet (17 subjects) or high glycaemic index diet (18 subjects). Glucose and insulin responses during a 75 g oral glucose tolerance test were assessed before and after dietary intervention and insulin-mediated glucose uptake was assessed in isolated adipocytes obtained at surgery.

RESULTS

The patients who consumed a low glycaemic diet had improved glucose tolerance and significantly greater in vitro adipocyte insulin sensitivity at the time of surgery compared with the high glycaemic diet group (78.87 +/- 10.64% versus 41.11 +/- 7%, respectively). The total length of stay in the patients on the low glycaemic diet was less than patients consuming the high glycaemic diet (7.06 +/- 0.38 days versus 9.53 +/- 1.44 days, P < 0.5).

CONCLUSION

This study provides further support that carbohydrate and fat metabolism influence cardiac outcome and provides new evidence that dietary modification prior to coronary artery bypass surgery can shorten hospital stay.

Magnetic resonance angiography

The field of MRA has progressed to a stage at which several clinical applications are of obvious value, including the diagnosis of cerebral aneurysms, venous disorders and disease of the carotid bifurcation. Additionally spin echo images are useful in studying the parenchyma and this together with MRA works to be an excellent diagnostic package in the presurgical workup of patients with cerebral vascular abnormalities. With further technical improvements, it seems likely that important applications of MRA will also be found in the diagnosis of peripheral artery disease, stenosis of the renal artery and ischemic heart disease. With the advent of fast imaging techniques like echoplanar imaging, the ability image the coronary and renal arteries accurately seems possible in the near future. At present, however the lack of optimal spatial resolution and the presence of flow artifacts precludes the use of this technique for imaging the vasculature with an accuracy comparable with conventional angiography. The advent for contrast 3-D CT angiography has resulted in a technique of studying the intracranial vessels immediately after assessing for the presence of subarachnoid hemorrhage. It is superior to MRA in demonstrating the actively filling and thrombused portions of giant, partially thrombused aneurysms and in planning the surgical approach in relation to bony landmarks. Though there are daunting obstacles, with continuous ongoing clinical research and the added inputs from a dramatically changing computer technology, MRA is all set to be an imaging study of great promise that may eventually replace diagnostic catheter angiography in most clinical situations.

Pre-conditioning with adenosine leads to concentration-dependent infarct size reduction in the isolated rabbit heart

Adenosine (ADO) has a cardioprotective effect in ischemia-reperfusion injury when administered both prior to ischemia and during reperfusion. ADO has also been implicated in the mechanism of ischemic pre-conditioning. The aim of this study was to investigate whether there was a concentration-response between the administration of ADO prior to ischemia-reperfusion and reduction in subsequent infarct size. Rabbit isolated perfused hearts were subjected to 45 min ischemia and 180 min reperfusion following pre-treatment with either Krebs Henseleit buffer alone or buffer containing ADO at a range of concentrations (3 micro M-100 micro M) for 5 min followed by 5 min perfusion with buffer. Infarct/risk ratios were significantly reduced in hearts pre-perfused with higher (> 3 micro M) concentrations of ADO (Control, 58.5 +/- 1.5%; 3 micro M ADO, 51.6 +/- 3.0% ; 6 micro M ADO, 44.1% +/- 2.0%; 10 micro M ADO, 33.3 +/- 1.9%; 20 micro M ADO, 26.6 +/- 0.9%; 50 micro M ADO, 21.6 +/- 3.5%; 100 micro M ADO, 23.0 +/- 0.6%). We conclude that pre-treatment with ADO leads to a concentration-dependent reduction in infarct size.

Inhibition of nitric oxide synthesis reduces infarct size by an adenosine-dependent mechanism

BACKGROUND

Nitric oxide (NO) is both a potent endogenous vasodilator with potential to attenuate ischemia-reperfusion injury and a mediator of tissue injury. The aim of the present study was to investigate the mechanism by which prior inhibition of NO synthesis can lessen ischemia-reperfusion injury in the isolated rabbit heart.

METHODS AND RESULTS

We examined the effects of inhibition of NO synthesis on infarct size using a model of coronary artery ligation in isolated rabbit hearts perfused at a constant flow rate of 35 mL/min. Infarct size averaged 65% of the zone at risk after 45 minutes of ischemia and 180 minutes of reperfusion. The addition of 30 mumol/L NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis, to the perfusate reduced the infarct-to-risk (I/R) ratio to an average of 41% (P < .05 versus control). This effect was abolished by pretreatment with 75.5 mumol/L 8-p-sulfophenyl theophylline (SPT), an adenosine receptor antagonist (I/R ratio, 63%). Ischemic preconditioning (5 minutes of ischemia and 10 minutes of reperfusion) before 45 minutes of ischemia and 3 hours of reperfusion reduced the I/R ratio to an average of 21%, and this was not augmented by pretreatment with L-NAME (I/R ratio, 20%). However, all protection due to preconditioning and L-NAME was lost in hearts pretreated with SPT (I/R ratio, 59%). In a separate set of experiments, adenosine concentration in the coronary perfusate and myocardial lactate concentrations were measured. Treatment with L-NAME increased the average adenosine concentration in the perfusate from 5.7 mumol/L per 100 g of heart (control) to a peak of 24.0 mumol/L per 100 g of heart; however, there was no effect on average myocardial lactate concentration (control, 4.6 mumol/g dry wt; L-NAME, 5.5 mumol/g dry wt). In contrast, after 5 minutes of global ischemia, the average adenosine concentration peaked at 139.0 mumol/L per 100 g of heart, and the average myocardial lactate concentration increased to 27.1 mumol/g dry wt.

CONCLUSIONS

Infarct size limitation after inhibition of NO synthesis shares a common mechanism with that of ischemic preconditioning and is dependent on the release of adenosine. However, in this model, adenosine release after inhibition of NO synthesis is not secondary to myocardial ischemia. The protection of the heart against ischemic injury by adenosine appears to be concentration dependent.

Adenosine receptor involvement in a delayed phase of myocardial protection 24 hours after ischemic preconditioning

BACKGROUND

We previously reported a delayed phase of protection against infarction 24 hours after ischemic preconditioning in the rabbit. In the present study, we investigated the possibility that this "second window of protection," like the well-described early phase of protection in the rabbit, might be associated with adenosine receptor activation.

METHODS AND RESULTS

In the first series of experiments, we examined whether adenosine receptor blockade with 8-(p-sulfophenyl)-theophylline (SPT) during preconditioning could abolish the delayed protection against infarction 24 hours later. Open-chest rabbits were subjected to myocardial preconditioning (PC) with the four 5-minute coronary occlusions or they were sham operated on (SHAM). During these procedures, animals received either SPT (PC + SPT, n = 6; and SHAM + SPT, n = 6) or vehicle (PC + VEH, n = 12; and SHAM + VEH, n = 11). Twenty-four hours later, infarct development after a 30-minute coronary occlusion/120-minute reperfusion insult was assessed with triphenyltetrazolium staining. In vehicle-treated rabbits, the infarct-to-risk ratio (I/R) was reduced from 53.6 +/- 5.7% (SHAM + VEH) to 32.9 +/- 4.6% (PC + VEH) (P < .05), clearly indicating a delayed phase of protection. Although I/R was not significantly different between SHAM + VEH (53.6 +/- 5.7%) and SHAM + SPT (61.7 +/- 5.4%), in PC + SPT the delayed protection was abolished (I/R = 56.8 +/- 3.8%). In the second series of experiments, we examined if pharmacological adenosine A1 receptor stimulation could evoke a delayed phase of protection. Conscious rabbits were pretreated with intravenous boluses of saline or the A1 receptor-selective agonist 2-chloro-N6-cyclopentyladenosine (CCPA), and infarct size in response to 30-minute ischemia/120-minute reperfusion was assessed 24 hours later. I/R was 54.5 +/- 2.7% in saline-pretreated controls (n = 12). Pretreatment with 25 micrograms/kg CCPA (n = 6), 50 micrograms/kg CCPA (n = 6), or 100 micrograms/kg CCPA (n = 6) resulted in I/R ratios of 37.1 +/- 4.2% (P < .01), 37.7 +/- 2.2% (P < .01), and 26.3 +/- 5.7% (P < .01), respectively. In both series of experiments, there were no differences in systemic hemodynamics during the infarct protocol, assessed as rate-pressure product, between the different experimental groups.

CONCLUSIONS

Twenty-four hours after repetitive brief coronary occlusions, susceptibility to infarction in rabbit myocardium is reduced, an effect that may have clinical relevance. Results of the present study suggest that this second window of protection following preconditioning may, like the early phase of protection, be initiated by an adenosine-related mechanism.

Inhibition of nitric oxide limits infarct size in the in situ rabbit heart

Recent data has suggested a dual role for nitric oxide (NO) so that it can both attenuate myocardial injury during ischaemia and reperfusion as well as mediate reperfusion injury. In this study in the in situ rabbit heart, we have shown that pretreatment with intravenous NG-nitro-L-arginine methyl ester (L-NAME, an inhibitor of NO synthesis) significantly reduced infarct size following sustained coronary artery occlusion and reperfusion. L-NAME was also noted to increase myocardial lactate concentration. This study provides further evidence that protection against ischaemia-reperfusion injury can be derived from manipulation of the microcirculation.

Drug absorption in spinal cord injury

The absorption characteristics of drugs in spinal cord injury (SCI) were studied using an actively transported drug [riboflavin (RBF)] and a passively absorbed drug [acetaminophen (ACE)]. RBF absorption was studied following oral administration of 150mg RBF as 5'-phosphate flavin mononucleotide in ten clinically complete quadriplegic patients (C1 to C7, two to 15 months post-onset) and six control subjects matched for age, sex, and weight. Urinary excretion was measured under fasting (F) and nonfasting (NF) conditions for time to peak, peak excretion rate, and percent dose recovered. The results showed a significant difference (p less than 0.05) for all parameters between F and NF conditions for both the SCI and able-bodied groups. However, there was no significant difference for the same parameters between the two groups. ACE absorption was studied in five SCI clinically complete quadriplegic patients (C1 to C7, two to 15 months post-onset following the administration of a 650mg tablet. Serum samples were analyzed for ACE content and showed: time of peak, 1.35 +/- 0.6hr; maximum serum level, 6.8 +/- 2.68 micrograms/ml; half-life, 2.89 +/- 1.81hr; absorption lag time, 18.1 +/- 1.8min; area under the serum level-time curve, 21.8 +/- 6.7 micrograms/.hr/ml. When compared to able-bodied population data in the literature, there was a significant increase in the time to peak and lag time, and a decrease in the maximum ACE serum concentration obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Endometriosis at the knee. A case report

A review of the world literature since 1928 failed to disclose a case of endometriosis affecting the knee. In the case of a 32-year-old women, synovial sarcoma was suspected on the basis of the histologic findings on frozen section, but final pathologic sections showed endometriosis. Synovial sarcoma classically consists if malignant stoma containing gland-like clefts and is easily confused with endometriosis. Affecting the extremities, endometriosis is rare. The condition should new be added to the differential diagnosis of extremity swelling in actively menstruating women.

Retroperitoneal malignant fibrous histiocytoma

The case report of a patient with a large retroperitoneal malignant fibrous histiocytoma treated with a combination of radiation therapy and surgery is presented. At the time of the first laparotomy, the lesion was deemed unresectable and biopsied. Reexploration after irradiation to a dose of 3800 rad showed the tumor to be more than 50% smaller and easily resectable. There has been no recurrence during the ensuing two and a half years.

Local anaesthetic activity of some sec-amino-N-(aryl-aralkyl)-ethyl acetamides

Six basic amides were screened for local anaesthetic activity and compared with procaine and lignocaine. Amongst the basic amides screened, piperidino-N-(alpha-4-ethoxy phenyl- beta-phenyl) ethyl and Diethylamino-N (alpha-4-ethoxy- beta-phenyl) ethyl acetamide were found to be more effective as compared to lignocaine. They were found to be non-irritant, and non-toxic even in high doses.

Diagnosis and treatment of obstructive jaundice secondary to liver metastases

Metastatic disease to the liver and adjacent lymph nodes and may cause jaundice by compression upon the major biliary ducts. Small field relatively high dose radiotherapy after accurate localization can result in effective palliation of jaundice in selected patients.

Diagnosis and treatment of obstructive jaundice secondary to liver metastases

Metastatic disease to the liver and adjacent lymph nodes and may cause jaundice by compression upon the major biliary ducts. Small field relatively high dose radiotherapy after accurate localization can result in effective palliation of jaundice in selected patients.