The Renin-Angiotensin System in COVID-19: Can Long COVID Be Predicted?

(1) Background: Co-morbidities such as hypertension and cardiovascular disease are major risk factors for severe COVID-19. The renin-angiotensin system (RAS) is critically involved in their pathophysiology and is counter-balanced by both angiotensin-converting enzyme 2 (ACE2), the functional receptor of SARS-CoV-2, and the kallikrein-kinin system (KKS). Considerable research interest with respect to COVID-19 treatment is currently being directed towards the components of these systems. In earlier studies, we noticed significantly reduced carboxypeptidase N (CPN, KKS member) activity and excessive angiotensin-converting enzyme (ACE, RAS member) activity in the sera of both hospitalized COVID-19 patients and a subgroup of convalescent patients. The data had been obtained using labeled bradykinin (BK) as a reporter peptide, which is a target of both CPN and ACE. The data were supplemented with mass-spectrometry-based serum proteomic analysis. Here, we hypothesize that the degree of BK serum degradation could be indicative of Long COVID. (2) Review and Discussion: The recent literature is briefly reviewed. The fact that the levels of the BK serum degradation products did not reach normal concentrations in almost half of the patients during convalescences could have been partially due to a dysregulated RAS. (3) Conclusions: Standard tests for routine patient care in Long COVID come often back normal. We suggest that the measurement of selected members of the RAS such as ACE and angiotensin II or the use of our BK degradation assay could identify Long COVID candidates. Clinical studies are required to test this hypothesis.

Security Analysis and Improvement of Vehicle Ethernet SOME/IP Protocol

The combination of in-vehicle networks and smart car devices has gradually developed into Intelligent Connected Vehicles (ICVs). Through the vehicle security protocol, ICVs can quickly realize communication transmission. However, with the more frequent connections between smart in-vehicle devices and the network, the relationship between intelligent cars and external systems is becoming more and more complicated, and in-vehicle networks are gradually facing many security issues. Strengthening the security of in-vehicle protocols has become particularly important. This paper uses the model building method based on the Colored Petri Net (CPN) theory to model the Scalable service-Oriented MiddlewarE over IP (SOME/IP) protocol of the vehicle Ethernet. The security protocol is formally verified and analyzed by combining it with the Dolev-Yao adversary model detection method. After verification, the protocol is subject to three attack vulnerabilities: replay, tampering, and deception. We introduce timestamps and random numbers to strengthen the protocol security. After the final analysis and verification, the improved scheme in this paper can effectively improve the security performance of the protocol.

Systematic review and meta-analysis of celiac plexus neurolysis for abdominal pain associated with unresectable pancreatic cancer

INTRODUCTION

Celiac plexus neurolysis (CPN) has been developed as adjunctive therapy to medical management (MM) of abdominal pain associated with unresectable pancreatic cancer. We aimed to conduct a systematic review and meta-analysis to obtain updated and more accurate evidence on the efficacy of additional types of CPN, including endoscopic ultrasound-guided CPN (EUS-CPN).

METHODS

On March 16, 2021, we performed searches of PubMed, Web of Science, and CENTRAL for original randomized controlled trials (RCTs). We defined the primary outcome as a standardized pain intensity score with a range of 0-10, and evaluated the mean difference between the CPN + MM and MM groups at 4, 8, and 12 weeks after the initiation of treatment. We used a random-effects model to synthesize the mean differences across RCTs.

RESULTS

We selected 10 RCTs involving 646 individuals. The synthesized mean difference in the pain intensity score between the CPN + MM and MM groups was -0.58 (95% confidence interval [CI]: -1.09 to -0.07) (p = 0.034) in favor of CPN + MM at 4 weeks, -0.46 (95%CI: -1.00 to 0.08) (p = 0.081) at 8 weeks, and - 1.35 (95%CI: -3.61 to 0.92) (p = 0.17) at 12 weeks.

CONCLUSIONS

This updated meta-analysis of CPN demonstrates its efficacy for managing abdominal pain at 4 weeks. Although there are various limitations, when abdominal pain in patients with unresectable pancreatic cancer is poorly controlled with MM alone, CPN should be an option even if the duration of effect is short-lived, taking into account the absence of serious adverse events.

A Novel Calcium Phosphate-Based Nanocomposite for Augmentation of Cortical Bone Trajectory Screw Fixation

Purpose

To evaluate the effect of cement augmentation of cortical bone trajectory (CBT) screws using a novel calcium phosphate–based nanocomposite (CPN).

Material and Methods

CBT screws were placed into cadaveric lumbar vertebrae. Depending on the material used for augmentation, they were divided into the following three groups: CPN, polymethylmethacrylate (PMMA), and control. Radiological imaging was used to evaluate the cement dispersion. Biomechanical tests were conducted to measure the stability of CBT screws. A rat cranial defect model was used to evaluate biodegradation and osseointegration of the CPN.

Results

After cement augmentation, the CPN tended to disperse into the distal part of the screws, whereas PMMA remained limited to the proximal part of the screws (P < 0.05). As for cement morphology, the CPN tended to form a concentrated mass, whereas PMMA arranged itself as a scattered cement cloud, but the difference was not significant (P > 0.05). The axial pullout test showed that the average maximal pullout force (Fmax) of CPN-augmented CBT screws was similar to that of the PMMA group (CPN, 1639.56 ± 358.21 N vs PMMA, 1778.45 ± 399.83 N; P = 0.745) and was significantly greater than that of the control group (1019.01 ± 371.98 N; P < 0.05). The average torque value in the CPN group was higher than that in the control group (CPN, 1.51 ± 0.78 N∙m vs control, 0.97 ± 0.58 N∙m) and lower than that in the PMMA group (1.93 ± 0.81 N∙m), but there were no statistically significant differences (P > 0.05). The CPN could be biodegraded and gradually replaced by newly formed bone tissue after 12 weeks in a rat cranial defect model.

Conclusion

The biocompatible CPN could be a valuable augmentation material to enhance CBT screw stability.

Reduced serum protease activity in Complex Regional Pain Syndrome: The impact of angiotensin-converting enzyme and carboxypeptidases

Complex Regional Pain Syndrome (CRPS) occurs in about 2% of patients after fracture of the limbs. In an earlier clinical study with 102 probands we have shown that the serum protease network in CRPS might be less effective. Based on these results we hypothesized that angiotensin-converting enzyme (ACE) and carboxypeptidase N (CPN) activity contribute to the differences of labeled bradykinin (DBK) degradation by patients' sera. Details of the enzymatic processes remained however unclear. The contributions of ACE and CPN in the serum degradation of DBK were studied using specific inhibitors. CPN1-ELISA was performed in serum. It was confirmed that the majority of DBK was degraded by ACE and CPN. The data delivered proof that the ACE serum activity was lowered in CRPS. High-resolution mass spectrometry was additionally used for protein expression analysis of sera of above study cohort (CRPS vs. healthy probands). According to principal component analysis of these data, significant differences between CRPS and control samples only occurred in sera of females younger than 46 years. In these CRPS patients, a number of defence / immunity-related proteins and members of the renin-angiotensin system (RAS) protein network were regulated. The impact of CPN in CRPS pathophysiology is subject to further investigation. The data support the hypothesis that both the RAS and the innate immune system might be affected in CRPS. A database of regulated serum proteins was established for future research.

Response to repeat echoendoscopic celiac plexus neurolysis in pancreatic cancer patients: A machine learning approach

BACKGROUND

/Objectives: Efficacy of repeat echoendoscopic celiac plexus neurolysis is still unclear. Aim of the study was to assess the efficacy of repeat celiac plexus neurolysis and to build an artificial neural network model able to predict pain response.

METHODS

Data regarding 156 patients treated with repeat celiac plexus neurolysis between 2004 and 2019 were reviewed. Artificial neural network and logistic regression models were built to predict pain response after treatment. Performance of the models was expressed in terms of accuracy, positive predictive value, and positive likelihood ratio.

RESULTS

Median age was 62 years (range 39-86) and most patients were male (66%) with pre-procedural visual analogue score 7. Fifty-one patients (32.6%) experienced treatment response, of which 6 (3.8%) complete pain suppression. Median duration of pain relief was 6 (2-8) weeks. Tumoral stage, interval from initial to repeat treatment, response to initial neurolysis, and tumor progression between the two treatments resulted as significant predictors of pain response. The performance of the artificial neural network in predicting treatment response was higher than regression model (area under the curve: 0.94, 0.89-0.97 versus 0.85, 0.78-0.89; p < 0.001). Positive predictive value and positive likelihood ratio resulted 90.3% and 19.35, respectively. Classification error rate was 5.7% with the artificial neural network compared to 14.7% of regression model (p < 0.001). These findings were confirmed through ten-fold cross validation.

CONCLUSIONS

Pain response following repeat neurolysis is generally less pronounced than after initial treatment. Artificial neural network may help to identify those subjects likely to benefit from repeat neurolysis.

An evidence-based algorithm for the management of common peroneal nerve injury associated with traumatic knee dislocation

Traumatic knee dislocation is a complex ligamentous injury that may be associated with simultaneous vascular and neurological injury.Although orthopaedic surgeons may consider CPN exploration at the time of ligament reconstruction, there is no standardised approach to the management of this complex and debilitating complication.This review focusses on published evidence of the outcomes of common peroneal nerve (CPN) injuries associated with knee dislocation, and proposes an algorithm for the management. Cite this article: Deepak Samson, Chye Yew Ng, Dominic Power. An evidence-based algorithm for the management of common peroneal nerve injury associated with traumatic knee dislocation. EFORT Open Rev 2016;1:362-367. DOI: 10.1302/2058-5241.160012.

Echoendoscopic ethanol ablation of tumor combined with celiac plexus neurolysis in patients with pancreatic adenocarcinoma

BACKGROUND AND AIM

Endoscopic ultrasonography guided-celiac plexus neurolysis relieves pain in patients with pancreatic cancer but with often suboptimal and transient results. The study aims to compare the efficacy and safety of endoscopic ultrasound-guided tumor ethanol ablation combined with celiac plexus neurolysis with respect to celiac plexus neurolysis alone for pain management in patients with pancreatic cancer.

METHODS

Among 123 patients with unresectable pancreatic cancer referred to our Institution between 2006 and 2014, 58 treated with endoscopic ultrasound-guided celiac plexus neurolysis (Group 1) and 65 with the combined approach (Group 2) were compared. Logistic regression models were applied to identify predictors of pain relief.

RESULTS

The two groups presented similar baseline clinical and tumoral parameters. Pre-procedural visual analog scale score was 7 in both groups (P = 0.8), and tumor max diameter was 38 mm (range 25-59) in Group 1 and 43 mm (22-59) in Group 2 (P = 0.4). The combined treatment increased pain relief and complete pain response rate (P = 0.005 and 0.003, respectively). Median duration of pain relief was 10 (7-14) and 18 (13-20) weeks in the two groups, respectively (P = 0.004). At multivariate regression, initial visual analog scale score and endoscopic technique adopted resulted significantly associated with pain relief. No severe treatment-related adverse events were reported. Median overall survival was 6.5 months (5.1-8.6) in Group 1 and 8.3 months (6-11.4) in Group 2 (P = 0.05).

CONCLUSIONS

Endoscopic ultrasound-guided tumor ablation combined with celiac plexus neurolysis appears to be superior to celiac plexus neurolysis alone in terms of pain control and overall survival.

Surgical outcome of foot drop caused by common peroneal nerve injuries; is the glass half full or half empty?

BACKGROUND

Foot drop is a gait abnormality with various etiologies. The Common Peroneal Nerve (CPN) is one of the most frequently injured peripheral nerves. CPN deficit leads to foot drop. Most CPN injuries recover spontaneously; nonetheless, some require nerve surgery. The present study set out to assess the surgical outcomes of foot drop following CPN injuries.

METHOD

Surgical outcomes were reviewed in 36 subjects with foot drop caused by CPN injuries, undergoing surgical nerve exploration. The CPN injuries were confirmed by physical examination, Magnetic Resonance Imaging (MRI) and electrodiagnostic findings.

RESULTS

Subsequent to surgery, a significant improvement was seen in the motor recovery of the subjects. Interestingly, no significant difference in the recovery was found between neurolysis and nerve repair (direct repair and nerve grafting). There was no significant association between the age and the functional recovery. Gender was not associated with the functional recovery. No significant difference was seen in the recovery between thigh-level and knee-level CPN divisions.

CONCLUSIONS

The findings from the present study suggest that nerve surgery can yield beneficial results in the recovery of foot drop following CPN injuries. In addition, the surgical outcome of neurolysis in the treatment of CPN injuries can be similar to that of the nerve repair (direct repair or nerve grafting). This may show the value of nerve repair, which was comparable to neurolysis in the treatment of CPN injuries.

Ambivalent roles of carboxypeptidase B in the lytic susceptibility of fibrin

BACKGROUND

Removal of C-terminal lysine residues that are continuously exposed in lysing fibrin is an established anti-fibrinolytic mechanism dependent on the plasma carboxypeptidase TAFIa, which also removes arginines that are exposed at the time of fibrinogen clotting by thrombin.

OBJECTIVE

To evaluate the impact of alterations in fibrin structure mediated by constitutive carboxypeptidase activity on the function of fibrin as a template for tissue plasminogen activator-(tPA) induced plasminogen activation and its susceptibility to digestion by plasmin.

METHODS AND RESULTS

We used the stable carboxypeptidase B (CPB), which shows the same substrate specificity as TAFIa. If 1.5 - 6μM fibrinogen was clotted in the presence of 8U/mL CPB, a denser fibrin network was formed with thinner fibers (the median fiber diameter decreased from 138 - 144nm to 89 - 109nm as established with scanning electron microscopy). If clotting was initiated in the presence of 5 - 10μM arginine, a similar decrease in fiber diameter (82 -95nm) was measured. The fine structure of arginine-treated fibrin enhanced plasminogen activation by tPA, but slowed down lysis monitored using fluorescent tPA and confocal laser microscopy. However, if lysis was initiated with plasmin in CPB-treated fibrin, the rate of dissolution increased to a degree corresponding to doubling of the plasmin concentration.

CONCLUSION

The present data evidence that CPB activity generates fine-mesh fibrin which is more difficult to lyse by tPA, but conversely, CPB and plasmin together can stimulate fibrinolysis, possibly by enhancing plasmin diffusion.

In and out from the cortex: development of major forebrain connections

In this review we discuss recent advances in the understanding of the development of forebrain projections attending to their origin, fate determination, and axon guidance. Major forebrain connections include callosal, corticospinal, corticothalamic and thalamocortical projections. Although distinct transcriptional programs specify these subpopulations of projecting neurons, the mechanisms involved in their axonal development are similar. Guidance by short- and long-range molecular cues, interaction with intermediate target populations and activity-dependent mechanisms contribute to their development. Moreover, some of these connections interact with each other showing that the development of these axonal tracts is a well-orchestrated event. Finally, we will recapitulate recent discoveries that challenge the field of neural wiring that show that these forebrain connections can be changed once formed. The field of reprogramming has arrived to postmitotic cortical neurons and has showed us that forebrain connectivity is not immutable and might be changed by manipulations in the transcriptional program of matured cells.

Carboxypeptidase N-deficient mice present with polymorphic disease phenotypes on induction of experimental autoimmune encephalomyelitis

Carboxypeptidase N (CPN) is a member of the carboxypeptidase family of enzymes that cleave carboxy-terminal lysine and arginine residues from a large number of biologically active peptides and proteins. These enzymes are best known for their roles in modulating the activity of kinins, complement anaphylatoxins and coagulation proteins. Although CPN makes important contributions to acute inflammatory events, little is known about its role in autoimmune disease. In this study we used CPN(-/-) mice in experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. Unexpectedly, we observed several EAE disease phenotypes in CPN(-/-) mice compared to wild type mice. The majority of CPN(-/-) mice died within five to seven days after disease induction, before displaying clinical signs of disease. The remaining mice presented with either mild EAE or did not develop EAE. In addition, CPN(-/-) mice injected with complete or incomplete Freund's adjuvant died within the same time frame and in similar numbers as those induced for EAE. Overall, the course of EAE in CPN(-/-) mice was significantly delayed and attenuated compared to wild type mice. Spinal cord histopathology in CPN(-/-) mice revealed meningeal, but not parenchymal leukocyte infiltration, and minimal demyelination. Our results indicate that CPN plays an important role in EAE development and progression and suggests that multiple CPN ligands contribute to the disease phenotypes we observed.