Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity

The Effect of Suture Caliber and Number of Core Strands on Repair of Acute Achilles Ruptures

Category: Sports Introduction/Purpose: Controversy exists in Achilles rupture management with options ranging from nonoperative care to open surgical repair. Current literature suggests re-rupture rates are lower with operative repair; therefore, surgery is recommended for active populations. The effect of suture caliber or number of core stands has not been studied in Achilles repair. Varying these factors may allow for a construct capable of earlier weight-bearing and rehabilitation. We hypothesized the number of core strands and suture caliber used in Achilles repair would significantly affect strength and gapping during a simulated early rehabilitation protocol. Methods: Sixteen cadaveric human foot and ankle specimens with no prior injuries or surgeries were utilized. Simulated midsubstance Achilles ruptures were created 6 cm proximal to the calcaneal insertion in 13 ankles. Specimens were randomly allocated to 1 of 4 groups: (1) intact Achilles tendon, (2) open repair using No. 2 suture with four core sutures and two 2mm suture-tape core sutures, (3) open repair using No. 2 suture with two core sutures and four 2mm suture-tape core sutures, and (4) open repair using No. 2-0 suture with 12 core sutures. Repairs consisted of three modified Kessler sutures and an epitenon stitch with a 3-0 monofilament suture. Specimens were subjected to a cyclic loading protocol simulating early, progressive postoperative rehabilitation: 250 cycles at 1 Hz for each loading range: 20-100, 20-200, 20-300, and 20-400 N. A 1-way ANOVA was used to test significance among repair groups. Results: During biomechanical testing, all repairs survived the first two loading stages. However, elongation trends during stage 1 (Figure 1) were consistent among subsequent cyclic loading stages. No significant elongation differences were observed between any of the repair groups (Groups 2-4), with mean displacements of 4.94 ± 0.90 mm, 3.93 ± 0.92 mm, and 5.35 ± 0.34 mm, respectively, at the end of the first loading stage. In Group 2, one repair failed during the fourth stage and 4 survived all four stages. In Group 3, one repair failed during the third stage and two repairs during the fourth stage. In Group 4, two repairs failed during the fourth stage and two survived all four stages. The average number of cycles to failure for Groups 2-4 was 967, 783, and 940 cycles, respectively. Conclusion: In this study, all but one repair survived 750 cycles. This was superior to a 6 core strand repair with No. 2 suture similarly evaluated in a previous study (427 cycles). When 4 of 6 strands were substituted with suture-tape, repair gapping decreased initially; yet, these repairs failed earlier. Gapping in Groups 2 and 4 was similar to the previously evaluated repair; however, the number of cycles to failure was higher. Therefore, substituting suture-tape for 2 core strands or doubling the core strands with a smaller caliber suture may be biomechanically superior and allow for earlier return to function

Intraarticular arthrofibrosis of the knee alters patellofemoral contact biomechanics

Abstract Background Arthrofibrosis in the suprapatellar pouch and anterior interval can develop after knee injury or surgery, resulting in anterior knee pain. These adhesions have not been biomechanically characterized. Methods The biomechanical effects of adhesions in the suprapatellar pouch and anterior interval during simulated quadriceps muscle contraction from 0 to 90° of knee flexion were assessed. Adhesions of the suprapatellar pouch and anterior interval were hypothesized to alter the patellofemoral contact biomechanics and increase the patellofemoral contact force compared to no adhesions. Results Across all flexion angles, suprapatellar adhesions increased the patellofemoral contact force compared to no adhesions by a mean of 80 N. Similarly, anterior interval adhesions increased the contact force by a mean of 36 N. Combined suprapatellar and anterior interval adhesions increased the mean patellofemoral contact force by 120 N. Suprapatellar adhesions resulted in a proximally translated patella from 0 to 60°, and anterior interval adhesions resulted in a distally translated patella at all flexion angles other than 15° (p < 0.05). Conclusions The most important finding in this study was that patellofemoral contact forces were significantly increased by simulated adhesions in the suprapatellar pouch and anterior interval. Anterior knee pain and osteoarthritis may result from an increase in patellofemoral contact force due to patellar and quadriceps tendon adhesions. For these patients, arthroscopic lysis of adhesions may be beneficial