In post-stroke aphasia, language tasks recruit a combination of residual regions within the canonical language network, as well as regions outside of it in the left and right hemispheres. However, there is a lack of consensus as to how the neural resources engaged by language production and comprehension following a left hemisphere stroke differ from one another and from controls. The present meta-analysis used activation likelihood estimates to aggregate across 44 published fMRI and PET studies to characterize the functional reorganization patterns for expressive and receptive language processes in persons with chronic post-stroke aphasia (PWA). Our results in part replicate previous meta-analyses: we find that PWA activate residual regions within the left lateralized language network, regardless of task. Our results extend this work to show differential recruitment of the left and right hemispheres during language production and comprehension in PWA. First, we find that PWA engage left perilesional regions during language comprehension, and that the extent of this activation is likely driven by stimulus type and domain-general cognitive resources needed for task completion. In contrast to comprehension, language production was associated with activation of the right frontal and temporal cortices. Further analyses linked right hemisphere regions involved in motor speech planning for language production with successful naming in PWA, while unsuccessful naming was associated with the engagement of the right inferior frontal gyrus, a region often implicated in domain-general cognitive processes. While the within-group findings indicate that the engagement of the right hemisphere during language tasks in post-stroke aphasia differs for expressive vs. receptive tasks, the overall lack of major between-group differences between PWA and controls implies that PWA rely on similar cognitive-linguistic resources for language as controls. However, more studies are needed that report coordinates for PWA and controls completing the same tasks in order for future meta-analyses to characterize how aphasia affects the neural resources engaged during language, particularly for specific tasks and as a function of behavioral performance. Aphasia is an acquired communication disorder in which individuals have difficulty with the production and/or comprehension of language, typically following a left hemisphere stroke. Recovery from aphasia is highly variable but largely dependent on stroke specific characteristics such as lesion size and location  is a meta-analysis technique that can be used to overcome the limitations of individual experiments. ALE can identify brain regions which are consistently activated across all imaging studies of interest. The algorithm then determines whether this convergence is higher than what would be expected from a spatially random distribution  framework  with a cluster forming threshold of p < 0.001 , a coordinate-based meta-analysis method, were calculated for each single condition and contrast of interest using GingerALE Version 3.0.2  with a 200 mm3 minimum volume . Contrast analyses were also used to conduct between-group comparisons for the combined language production and comprehension, language production only, language comprehension only, and four task-specific analyses . Contrast analyses use ALE maps thresholded for multiple comparisons, therefore the contrast threshold was set to uncorrected We first computed an ALE which combined language production and comprehension in a single analysis to identify neural resources which are generally engaged by language in PWA and controls, regardless of task.p < 0.001 corrected; The combined ALE included all 50 tasks  and identified five significant clusters for PWA in bilateral fronto-temporal regions. Peak activations within the temporal lobe included the right posterior superior temporal gyrus and left posterior middle temporal gyrus. In the frontal lobe, peak activations were in the left superior and middle frontal gyri, as well as the right anterior insula (largest cluster). These peak activations additionally extended into the bilateral inferior frontal gyri, left medial frontal gyrus, left cingulate gyrus, left posterior insula, and right middle and precentral gyri . This ALE identified seven significant clusters in controls. The largest cluster's peak was in the left inferior frontal gyrus (pars opercularis). Subsequent peaks were identified in the left superior frontal gyrus, left precentral gyrus, left middle temporal gyrus, left superior temporal gyrus, right superior temporal gyrus (two peaks), and left superior parietal lobule . Smaller activations were found in the left superior frontal gyrus, left medial frontal gyrus, and left posterior superior temporal gyrus (three peaks). The remaining three peaks were in the right hemisphere and included the right medial frontal gyrus, right anterior insula, and right posterior middle temporal gyrus. As expected, the contrast analysis revealed controls activate the canonical language network more than PWA (likely at least in part due to PWA having lesions in these left perisylvian areas). The largest peak activation for controls compared to PWA was found in the left inferior frontal gyrus (pars opercularis), with smaller activations being identified in the left inferior frontal gyrus (pars triangularis), left superior parietal lobule, left anterior and posterior superior temporal gyrus, left posterior middle temporal gyrus, right medial frontal gyrus, and right anterior superior temporal gyrus. Conversely, PWA, compared to controls, only activated the right inferior frontal gyrus (pars triangularis) more during all language tasks  and Wernicke's aphasia (3 studies with 8 PWA). However, these ALEs should be interpreted with caution due to having fewer than eight studies included. The findings from both the Broca's and Wernicke's aphasia ALEs align with the production results from the larger PWA sample. The Broca's aphasia ALE identified four significant clusters with peaks in the right precentral gyrus (largest peak), right middle frontal gyrus, right medial frontal gyrus, and left postcentral gyrus. The Wernicke's aphasia ALE identified three significant clusters with peaks in the right inferior frontal gyrus , right middle temporal gyrus, and left caudate . Additional peaks were identified in the left superior frontal gyrus, left middle temporal gyrus, left superior temporal gyrus, right insula, and right superior temporal gyrus , right posterior superior temporal gyrus, and right anterior insula. PWA did not significantly activate any regions more than controls during language production. However, the analysis identified seven clusters significantly more active in controls than PWA: the largest cluster was in the left inferior frontal gyrus (pars opercularis), and smaller clusters were identified in the left superior frontal gyrus, bilateral posterior middle temporal gyri, right anterior superior temporal gyrus, and right inferior frontal gyrus . However, post-hoc analyses dividing the comprehension tasks by sensory modality  and left middle temporal gyrus  with the largest cluster being in the left pars orbitalis. One additional peak, in the left posterior middle temporal gyrus, was also observed to be activated by both PWA and controls during language comprehension. PWA significantly activated the left precentral gyrus more so than controls, while controls significantly activated the left middle frontal gyrus more than PWA  that reported aphasia data. The conjunction analysis identified seven significant clusters activated for language production and comprehension in PWA. These regions included the left middle, superior, and medial frontal gyri, left middle temporal gyrus (three clusters), and right anterior insula (largest cluster). The production greater than comprehension ALE in PWA identified the right precentral gyrus and right posterior superior temporal gyrus (largest cluster) to be more activated during language production than comprehension. For comprehension greater than production, PWA activated the left inferior frontal gyrus (pars triangularis) the most, but also the left superior frontal gyrus, left precentral gyrus, left posterior middle temporal gyrus (two peaks), left anterior superior temporal gyrus, right middle frontal gyrus, and right putamen  that included control data. The conjunction analysis identified eight clusters activated by production and comprehension in controls. These clusters had peaks in the left inferior frontal gyrus , left inferior frontal gyrus , left middle frontal gyrus (two peaks), left insula, and left middle temporal gyrus. The production greater than comprehension analysis identified five significant clusters. The largest cluster's peak was in the left medial frontal gyrus. Subsequent peaks were identified in the left middle frontal gyrus, right inferior frontal gyrus (pars triangularis), and right superior temporal gyrus (two peaks). Controls significantly activated two clusters for comprehension greater than production, the largest cluster was in the left middle temporal gyrus, and the other in the left inferior frontal gyrus  (Table 5 and depicted in p < 0.001 corrected). The ALE using all 15 picture naming tasks identified two significant clusters in PWA. The largest cluster's peak was in the right posterior superior temporal gyrus and extended into the right posterior middle temporal gyrus. The smaller cluster's peak was in the right precentral gyrus and extended into the right inferior frontal gyrus . The ALE for incorrectly named items should be interpreted with caution as it only included four studies with 12 PWA. Nonetheless, this ALE did identify activation of voxels in the right inferior frontal gyrus (pars opercularis) and right posterior middle temporal gyrus when items were incorrectly named (p < 0.001 corrected). No brain regions were significantly more active during correct naming than incorrect naming, but voxels in the right inferior frontal gyrus (pars triangularis) were found to be significantly more activated during incorrect naming than correct naming (p = 0.05 uncorrected).To explore activations related to naming task performance, we additionally conducted p < 0.001 corrected; Seven articles included 105 control participants completing a picture naming task during scanning. The control ALE identified one cluster in the left inferior frontal gyrus , left middle frontal gyrus, left medial frontal gyrus, and right superior temporal gyrus . A post-hoc ALE of performance-related activations for word generation tasks could not be computed because no word generation study reported whether the coordinates were associated with correct or incorrect responses.Eight articles included word generation tasks while scanning 62 PWA. The ALE for word generation resulted in five significant clusters with the largest peak being in the right posterior superior temporal gyrus, and smaller peaks in the right anterior insula, left posterior middle temporal gyrus, left cingulate gyrus, and left middle frontal gyrus , left superior frontal gyrus, left precentral gyrus, and right inferior frontal gyrus  during word generation. PWA activated no brain regions more than controls. The control greater than PWA ALE identified four significant clusters including the left inferior frontal gyrus , left middle frontal gyrus, left superior frontal gyrus, and right inferior frontal gyrus . A post-hoc ALE of performance-related activations for semantic decision tasks could not be computed because only two studies reported whether the coordinates were associated with correct or incorrect responses.Eight articles included 91 PWA completing a semantic decision task during scanning. The ALE for semantic decisions identified two significant clusters; the largest cluster peaked in the left posterior middle temporal gyrus and the smaller peak was in the left inferior frontal gyrus . A post-hoc ALE of performance-related activations for auditory sentence listening tasks could not be computed because no study reported whether the coordinates were associated with correct or incorrect responses.In seven studies, 109 PWA listened to auditory sentences during scanning. The ALE for auditory sentence listening identified six clusters. Five clusters were located in the left hemisphere: the largest peak was in the left inferior frontal gyrus , and smaller peaks were identified in the left middle frontal, superior frontal, posterior middle temporal, and anterior superior temporal gyri. The sixth peak was in the right claustrum . Correct and incorrect responses both activated right fronto-temporal regions: correct responses activated the right precentral gyrus and right superior temporal gyrus, and incorrect responses activated the right inferior frontal gyrus (pars opercularis) and right middle temporal gyrus. Contrasting correct and incorrect responses further linked the right inferior frontal gyrus (pars triangularis) with unsuccessful naming. Although activation of the right inferior frontal gyrus has generally been associated with better language abilities, particularly when the left inferior frontal gyrus is lesioned , there are nonetheless limitations. First, our inclusion criteria were limited to PWA in the chronic recovery stage. Thus, our findings cannot be extended to the acute and sub-acute phases. In the acute and sub-acute phases, the current evidence indicates that language is initially supported by right hemisphere resources before gradually transitioning to left perilesional regions as language recovers  was described in each study . In total, 11/50 tasks reported coordinates associated with behavioral performance of some kind. Of these 11 studies, nine were the picture naming tasks we computed ALEs for, and two were comprehension tasks (both semantic decision tasks). To overcome this limitation, future fMRI and PET studies of language recovery in aphasia should ideally include correlations between behavioral performance and brain activations, and separately report coordinates for correct and incorrect responses. This type of consistency in the literature will strengthen our understanding of the effectiveness of compensatory strategies to post-stroke language recovery.This meta-analysis is also limited in that it only partially accounts for the relationship between neural activation and behavioral performance. This is not due to a methodological limitation of the current study, but rather a function of what studies are available in the published literature for us to input into our meta-analysis. While there was  sufficient data to conduct Our inclusion criteria were further limited to whole brain analyses and tasks that utilized a non-speech baseline task . While each of these criteria was necessary to balance sufficient power and homogeneity (Müller et al., A final limitation of the present work is our focus on studies reporting coordinates not related to treatment. Thus, from the present meta-analysis, it is difficult to infer how treatment affects the neural resources supporting language. The heterogeneity of treatment interventions and methodological approaches makes it difficult to include these studies in an ALE meta-analysis, yet there is certainly evidence that behavioral treatments can influence the neural resources that are recruited during language tasks. For example, Cherney and Small  report oOur exhaustive meta-analysis of language activations in PWA identified different intra- and inter-hemispheric functional organization patterns for production and comprehension. As expected, PWA activated the left middle and superior temporal gyri during language comprehension. We found additional intra-hemispheric activations in the left frontal gyri, but notably none in the right temporal lobes, which contrasted with what was expected based on predictions from the dual stream models (Hickok and Poeppel, The original contributions presented in the study are included in the article/AL and CR contributed to study conception and design. AL and EJ conducted the literature search and performed the statistical analyses. AL wrote the first draft of the manuscript. All authors contributed to manuscript revision, read, and approved the submitted version.This research was supported by Midwestern University and Arizona State University.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Hyperuricemia is common in chronic kidney disease (CKD) and may be present in 50%of patients presenting for dialysis. Hyperuricemia can be secondary to impairedglomerular filtration rate (GFR) that occurs in CKD. However, hyperuricemia canalso precede the development of kidney disease and predict incident CKD.Experimental studies of hyperuricemic models have found that both soluble andcrystalline uric acid can cause significant kidney damage, characterized byischemia, tubulointerstitial fibrosis, and inflammation. However, most Mendelianrandomization studies failed to demonstrate a causal relationship between uricacid and CKD, and clinical trials have had variable results. Here we suggestpotential explanations for the negative clinical and genetic findings, includingthe role of crystalline uric acid, intracellular uric acid, and xanthine oxidaseactivity in uric acid-mediated kidney injury. We propose future clinical trialsas well as an algorithm for treatment of hyperuricemia in patients with CKD. The relationship of serum uric acid with incident CKD is notlinear, but risk shows a rapid increase as serum uric acid concentrations reach7 mg/dL or more,,,,,Hyperuricemia is a strong independent risk factor for incident CKD14-,22-28. 14-1,22-28. ,,Some genetic studies also suggest that hyperuricemia may confer risk for CKD,especially in Mexican American, Native American, and Italian populations,,,,,These controversial results could be a consequence of selection biases due to theheterogeneity of the hyperuricemic population. For example, it may make adifference whether the hyperuricemia is primary  or secondary . Another variable could be the level ofhyperuricemia, for, as mentioned, the relationship between serum uric acidlevels and the development of CKD is not linear but increases exponentially forvalues of serum uric acid > 7 mg/dL and especially > 9 mg/dL,,There is also some evidence that the biologic effects of uric acid to causekidney disease may be mediated more by the intracellular effects of uric acid asopposed to serum uric acidHyperuricemia is thought to cause kidney injury by both crystal-dependent andcrystal-independent mechanismsThe crystal-dependent pathway involves the deposition of monosodium uratecrystals in the tubules or interstitium in the kidney in the outer medulla thatleads to chronic inflammation and tubular damage,-Soluble, intracellular uric acid may also cause CKD via a crystal-independentprocess. This may occur by either uptake of uric acid from the circulation or byendogenous generation such as from dietary fructoseExperimental trials of uric acid lowering drugs in CKD have been mixed . One ana,More recently, two large clinical trials, the Preventing Early Renal Loss inDiabetes (PERL) and the Controlled Trial of Slowing of Kidney DiseaseProgression from the Inhibition of Xanthine Oxidase (CKD-FIX) studies, werepublished in which significant progression did occur in the control groups butfor which no benefit in treatment of uric acid levels were notedBefore any recommendations are provided, it is important to discuss the potentialtoxicities of the various treatments. Allopurinol is a xanthine oxidaseinhibitor that is usually well tolerated, but it can be associated with a severehypersensitivity syndrome mimicking a Stevens Johnson syndrome in individualscarrying the HLA B58 alleleOther uric acid lowering agents include uricosurics, but these are notrecommended in patients with CKD as acute rises in urine uric acid may causetransient worsening of kidney function. However, this may be mitigated bycombining a uricosuric with a xanthine oxidase inhibitor. Finally, uric acid canalso be lowered by recombinant uricases such as pegloticase and rasburicase.However, some individuals may develop antibodies to these agents that can limittheir eventual effectiveness.Clearly, more clinical trials are needed. However, based on the fact that markedhyperuricemia appears to carry significant risk for kidney disease progressionthat could involve both crystal-dependent and -independent mechanisms, wesuggest that treatment should be considered for individuals with serum uric acidconcentrations of 8 mg/dL or higher and evidence of progression of their kidneydisease, as well as patients with a history of gout irrespective of theirunderlying serum uric acid concentration. In In summary, hyperuricemia is a risk factor for CKD, and there is strong evidencethat it can cause kidney disease by either crystal-dependent or -independentmechanisms. Nevertheless, trials examining the effects of uric acid loweringinterventions in CKD have been inconsistent, although this be ascribed to thetrials not targeting the participants most likely to benefit, which are thosewith hyperuricemia and/or a history of gout. Until further trials are done, westill would recommend urate-lowering drugs for this target population providedthey show evidence of progression of their kidney disease. Careful attention tothe potential toxicities of urate-lowering drugs is needed.


Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid malignancies, with a five-year survival rate of only ~10%. Pancreatic tissue becomes increasingly fibrotic (known as desmoplasia) during cancer development and progression. This extensive, heterogeneous reaction is largely mediated through the actions of stromal cells such as cancer-associated fibroblasts (CAFs). In this review, we will discuss how heterotypical reciprocal tumor-stromal and tumor-immune cell interactions in the pancreatic tumor microenvironment (TME) can both promote and restrain PDAC development and progression, with particular focus on the role of extracellular matrix (ECM) in potentiating tumor cell proliferation, survival, metastasis, and treatment resistance. We also give a snapshot of the current and emerging stromal co-therapies used in combination with chemotherapy or immunotherapy to treat this highly deadly disease.Many cancer studies now recognize that disease initiation, progression, and response to treatment are strongly influenced by the microenvironmental niche. Widespread desmoplasia, or fibrosis, is fundamental to pancreatic cancer development, growth, metastasis, and treatment resistance. This fibrotic landscape is largely regulated by cancer-associated fibroblasts (CAFs), which deposit and remodel extracellular matrix (ECM) in the tumor microenvironment (TME). This review will explore the prognostic and functional value of the stromal compartment in predicting outcomes and clinical prognosis in pancreatic ductal adenocarcinoma (PDAC). We will also discuss the major dynamic stromal alterations that occur in the pancreatic TME during tumor development and progression, and how the stromal ECM can influence cancer cell phenotype, metabolism, and immune response from a biochemical and biomechanical viewpoint. Lastly, we will provide an outlook on the latest clinical advances in the field of anti-fibrotic co-targeting in combination with chemotherapy or immunotherapy in PDAC, providing insight into the current challenges in treating this highly aggressive, fibrotic malignancy. Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer representing 95% of all patients and remains one of the most lethal forms of human cancer worldwide, with >90% of patient deaths occurring within one year of diagnosis . PDAC isPDAC is thought to arise in the ductal cells of the exocrine glands and is widely accepted as progressing through a number of pre-invasive pancreatic intraepithelial neoplasm (PanIN) stages before the development of PDAC. Several large-scale epidemiological and genetic studies have recently led to the identification of a large range of potential oncogenic drivers of the disease ,14,15. DIn addition to this high genetic and molecular diversity, PDAC is also one of the most stromally-dense cancer types across all malignancies, with stromal desmoplasia or fibrosis accounting for up to 90% of the total tumor volume . This deG12D; p53R172H; PdxCre) and human PDAC specimens, distinct fibroblast subpopulations have been identified including myofibroblasts (myCAFs), inflammatory fibroblasts (iCAFs) and antigen presenting CAFs (apCAFs) . C. C77]. CThe pleiotropic transcription factor Myc mediates the expression of multiple genes, which coordinate several aspects of cell proliferation and is tightly controlled by mitogen availability in normal cells. However, upon activation of upstream oncoproteins in disease, aberrant Myc activation can drive cell proliferation and tumor growth. In a stromal context, Myc acts as a switch where its reversible activation in PanINs triggers the release of paracrine signals that coordinate stromal and immunological changes driving disease progression e 79]. P. P79]. PThe pancreatic stroma also harbors numerous innate and adaptive immune cells that potentially suppress anti-tumoral immune responses. In PDAC, the interleukin-17 (IL17) family is involved in multiple aspects of disease progression including neoplastic cell transformation f 80]. I. I80]. IThe biochemical and protein compositions of normal tissues have been well documented and are extensively recognized as regulators of cell behavior, mechanical forces and physical properties acting upon cells ,91. ReceTyrosine kinase/Ras signaling is one of the main regulators of cell mechanics and an integral element in the reprogramming of normal cells into tumor cells upon KRAS mutation. For example, Panciera et al., (2020) reported that reprograming of normal cells into tumor precursors can also require enhanced ECM stiffness and oncogenic mechanosignaling . Here, iStiffening of the tumor ECM is regulated and sensed by mechanoreceptors such as integrins, which physically connect cells to the ECM and can stimulate multiple intracellular mechanosignaling proteins such as Rho-associated kinase (ROCK), FAK, RhoA, JAK/STAT and PAK . It has It has been well documented that FAK phosphorylation is a key step in the mechanosensory process . During The integrin signaling axis bridges signaling between the ECM to the contractile actin cytoskeleton, transducing bi-directional responses between cancer cells and stroma in order to guide cellular fate  Figure . This isCell proliferation and differentiation require the metabolism of nutrients for both energy and biosynthesis of macromolecules. CAFs exhibit diverse functions to sustain tumor growth including providing metabolic support to enable neoplastic proliferation. Recently, a connection between tissue mechanics and cell metabolism has been identified ,116. TheIt is becoming increasingly apparent that the collagen-rich ECM of PDAC can restrict nutrients and oxygen to the tumor cells. However, altered metabolism of PDAC cells means that this meshwork can also serve as a proline reservoir for cells, promoting their survival under previously nutrient deficient conditions . SimilarThe majority of PDAC patients present with inoperable, locally advanced, or metastatic disease, making systemic chemotherapeutic regimes standard-of-care in this advanced setting. Currently, gemcitabine, gemcitabine/Abraxane or FOLFIRINOX offer limited improvement in survival. In recent years, our enhanced understanding of the intricate PDAC TME, including its cellular and structural components as well as its interactions with the cancer cells, has alluded to several potential therapeutic opportunities to co-target the TME in PDAC .As CAFs are one of the main contributors to tumor development and progression in PDAC, this dynamic stromal cell population offers a promising therapeutic target, despite their known functional heterogeneity. Stromal desmoplasia in PDAC tumors is purported to be a major biochemical and physical barrier to effective drug delivery in the treatment of PDAC. It is thought that the dense, fibrotic ECM blocks drug penetrance via increases in interstitial fluid pressure (IFP) and hypo-vascularisation. This results in reduced treatment efficacy and resistance to current therapeutics. In recent times, there have been many attempts to co-target CAFs to enhance standard-of-care chemotherapy and emerging treatments such as immunotherapy. Generally speaking, CAFs can be targeted directly or by attempting to reprogram them towards a tumor-restraining phenotype. Similarly, there has also been attempts to block or normalize the reciprocal signaling between the CAFs, tumor cells and other cells of the TME to impede tumorigenesis. Thus far, co-targeting CAFs effectively has been challenging, most likely due to a lack of specific CAF markers, as well as their inherent plasticity in vivo.The hedgehog signaling pathway is one of the most studied stromal co-targets for the treatment of PDAC. In PDAC, activation of the Hedgehog pathway results in CAF activation via paracrine signaling with adjacent cancer cells, leading to aberrant ECM deposition and promotion of tumorigenesis ,128. In Another study by Elahi-Gedwillo et al., (2019) reported that normalization of the stromal microenvironment using the anti-fibrotic agent halofuginone resulted in disruption of the matrix to improve drug distribution through decreased fibroblast activation . ConcomiIn the clinic, resection of locally advanced disease is often prevented by the encasement of major mesenteric vessels by the dense ECM. Neoadjuvant chemotherapy in combination with a monoclonal antibody against connective tissue growth factor (pamrevlumab) holds promise for improving resection rates in patients with locally advanced PDAC, as a pre-clinical study showed this combination reduced the dense and fibrotic encapsulation of critical blood vessels . FurtherIn recent times, nanomedicines have begun to emerge as a new treatment modality for cancer patients, owing to their high tissue specificity, excellent pharmacokinetics, therapeutic efficiency, and minimal side effects. Recently, nanomedicines have been manufactured to exquisitely modulate unique aspects of the TME, demonstrating highly effective anti-tumor and anti-metastatic properties, whilst also enhancing drug efficiency ,140. ForThe cellular and architectural compartments of the PDAC TME play a significant role in disease development, progression, and therapeutic response . Here, w


Innate immunity, with broad efficacy and specificity, holds great promise for developing broad anticancer therapeutics. Neutrophils, also known as polymorphonuclear cells (PMNs), the most prevalent immune cells that act as crucial effectors of innate immunity, are of particular interest due to their ability to eliminate genetically diverse pathogens.+ T cells. These new findings collectively provide an intriguing avenue for broad anticancer therapies and new insights into selective cancer cell killing.Cui et al. showed that human PMN media under serum-free conditions (apoptotic PMNs) can kill 35 different human or murine cancer cells across 11 tumor types but spare healthy cells  of ELANE treatment induces cancer cell death, while the shorter time point (1 h) promotes cellular proliferation.3 Therefore, it is of importance to explore the optimized timing of ELANE treatment with the aim of its clinical application as an anticancer treatment option.Curiously, Cui et al. found that apoptotic PMN media from diverse human sources, but not that from murine sources, can inhibit tumor growth. Mechanistically, secretory leukocyte peptidase inhibitor (SLPI), a serpin (serine protease inhibitor), is co-released with ELANE in murine neutrophils, but not in human neutrophils, and SLPI can bind to ELANE, thereby resulting in the loss of ELANE activity in murine neutrophils. The species specificity and mechanistic insights throw new light on conceptualizing the contentious roles of neutrophils in tumor development.4 In this regard, it is of importance to evaluate the potential toxicity of ELANE to non-cancer cells in vivo in long-term ELANE-based therapy.In this study, the combination of diverse mouse models clearly demonstrated that ELANE can attenuate tumor growth in vivo. However, this in vivo therapeutic efficacy of ELANE is much attenuated compared with its remarkable in vitro potency, raising the possibility that SLPI or other serpins may inactivate extracellular ELANE activity in vivo. Indeed, this study revealed that three serpins secreted by cells in the tumor microenvironment (TME), including A1AT, SERPINB1, and SLPI, can antagonize ELANE’s anti-tumor capability in a dose-dependent manner. In addition, most of circulating ELANE could be neutralized by the serum that contains some endogenous serpins. Hence, the presence of serpins in serum and TME may represent one of the potential obstacles of ELANE therapy. In line with this, porcine pancreatic elastase, an ELANE homolog showing less susceptibility to serpins, exhibited remarkably improved therapeutic efficacy in vivo, exemplifying a promising direction to optimize ELANE therapy. Of note, the crosstalk between ELANE and serpins has been implicated in many physiological and pathological processes. For instance, the imbalance of ELANE and serpins might lead to inflammatory lung diseases.5 Therefore, it is highly commendable to identify the abscopal effect of ELANE. Combined with observations of ELANE’s non-toxicity to immune cells and previous findings that ELANE uptake by cancer cells can result in enhanced activation of cytotoxic CD8+ T cells, Cui et al. demonstrated that ELANE attenuates distant tumorigenesis via activating cytotoxic CD8+ T cells, which is independent of immune reaction. Although much remains to be furtherly explored, the innate immune system initiated by ELANE could drive adaptive immunity. Currently, the growing consensus is that a combination of immunotherapy with radiotherapy can boost the abscopal effect.5 Hence, ELANE therapy supplemented with radiotherapy perhaps holds significant potential to improve patient outcomes.Metastasis accounts for most of the cancer-related death. Interestingly, this study showed that ELANE therapy on the primary tumor can attack distant metastases, which is not due to ELANE spillover. This so-called abscopal effect is vanishingly rare, which is ascribed to the established immune-tolerance mechanisms.Despite these tremendous advances, this anticancer pathway of ELANE may require experimental validation in more cell types. Future studies aimed at the mechanism by which histone H1 and CD95-DD complexes trigger apoptosis will shed more light on the cancer-selective property of ELANE. Moreover, combination therapies with ELANE that could improve in vivo efficacy are worthy of further exploration.In short, the study by Cui et al. demonstrates the great value and potential of ELANE therapy. Moreover, it provides new mechanistic insights into broad and selective anticancer therapy and paves the way for new therapeutic strategies.


N = 160). Dyadic data were analyzed among couples withcancer to examine the within-person (actor effects) and between-partner (partnereffects) associations among links between cancer-related communication andcancer-related distress through the use of actor–partner interdependence models.Significant actor and partner effects were found for cancer-relatedcommunication in partners facing cancer, a factor that predicted cancer-relateddistress. The findings underscore the need to adopt a systemic perspective thataccounts for multiple, simultaneous adaptive processes including cancer-relatedcommunication as influences on cancer-related distress in the time ofCOVID-19.The present study draws attention to the significance of consideringcancer-related communication on cancer-related distress through thevulnerability–stress–adaptation model among couples with cancer during thepandemic. This is a quantitative dyadic study with a sample of 80 couples( With social distancing becoming the new normal, many couples are getting stuck at hometogether and their routines got disrupted. This can get worse for couples dealing withpreexisting conditions such as cancer. Patients with cancer may be vulnerable toCOVID-19 due to their immunecompromised systems. Furthermore, disruptions to treatmentsessions due to the stay-at-home orders may add even more distress to couples withcancer and their relationship . The strCancer is a chronic illness characterized by the growth of mutated cells in the body. Cancer affects not only individuals but also familymembers, most notably romantic partners .TherefoWhile cancer has become a public issue in the United States, the struggles of couplescoping with cancer often remain private challenges that affect their romanticrelationship, physical health, and mental health well-being. While the trials ofpatients with cancer are well represented in cancer literature ,there hUnlike some other chronic illnesses, the progression of cancer and its consequences is rapid and does notallow partners to prepare for the changes  in their lives .This hiReceiving the news of a cancer diagnosis is a highly stressful event . It leadFurthermore, couples cope with cancer and cancer-related distress by enacting ahost of diverse adaptive processes .EffectiThe way in which couples communicate and how partners communicate work througharguments about their cancer diagnosis is of primary importance . The wayGiven the unparalleled growth in the number of couples with cancer in the UnitedStates , it is cenduring vulnerabilities, stressfulevents, and adaptive processes often contribute tomarital quality and stability  and between-partner (partner effects) associationsamong links between on cancer-related communication and cancer-related distressthrough the use of actor–partner interdependence models APIMs; .N = 160).All participants, both the partners with cancer and those who were in arelationship with them, were recruited using Qualtrics Panel, an online surveypanel service. Qualtrics Panel is an online research company that helpsresearchers have access to nationwide samples. Couples with cancer were includedin the study if (1) both partners were 18 years or older, (2) one partner wasdiagnosed with cancer, (3) both partners were fluent in reading and writingEnglish, and (4) partners had been in a committed relationship with one anotherfor a minimum of 6 months before participating in the study. Based on estimatesfrom a web-based calculator designed for APIM , thetarAfter receiving the Institutional Review Board approval, the target sample wasrecruited via Qualtrics Panel to participate. The couple as a unit received U.S.$15 as an incentive for their participation after each partner of the romanticdyad completed the survey. It took approximately 10 min for eachpartner/participant to fill out the survey. All measures were completed via aself-reported online survey and are described below.Participants first completed demographic information including age, gender, race,ethnicity, yearly income, level of education, months in a committed relationshipwith the current partner, relationship status, type of cancer, stage of cancer,type of treatment, and whether they had had surgery or not. Following thecompletion of the demographics portion of the survey, participants completed themeasures described below.not at all), 2 (a little bit), 3(moderately), 4 (quite a bit), and 5(extremely). Scores are summed and range from 8 to 40,with greater scores indicating a higher level of distress and anxiety aboutthe cancer diagnosis in a romantic relationship  to 9 (likely), with higherscores suggesting healthier communication about the cancer diagnosis in aromantic relationship . Thus, partners facing cancer who reported greatercancer-related communication also reported a lower level of cancer distress.Additionally, we discovered that greater cancer-related communication as reported byPartner 1 or 2 had negative partner effects. Greater cancer-related communicationreported by Partner 1 or 2 was significantly, negatively linked with their partners’reports of lower level of cancer distress . Therefore, when partners of cancer patients orpatients themselves reported greater cancer-related communication, their partnersreported a lower level of cancer distress during the pandemic time. This modelaccounted for 58.4% of the variance of cancer-related distress in Partner 1 and46.1% of the variance cancer-related distress in Partner 2.Although the importance of adaptive processes such as cancer-related communicationfor couples facing cancer and their cancer-related distress and romanticrelationships have been highlighted in previous studies , there iTo this end, the current study extended the literature by examining howcancer-related distress as an adaptive process may be associated with cancer-relateddistress in couples with cancer during the pandemic. Data analysis partiallysupported the hypotheses mentioned above. Significant actor and partner effects werefound for cancer-related communication in partners facing cancer, a factor thatpredicted cancer-related distress. The findings underscore the need to adopt asystemic perspective that accounts for multiple, simultaneous adaptive processesincluding cancer-related communication as influences on cancer-related distress inthe time of COVID-19.The noteworthy findings from this study were that cancer-related communication incouples facing cancer had both actor and partner effects on cancer-relateddistress. In line with Previous research has shown that not all communication about cancer is helpful,and specific types of communication  have been associated with lower levels of physicaland mental health .On the oIt is worth mentioning that no published study has examined the impact ofcancer-related communication on cancer-related distress in couples with cancerfrom dyadic data and through APIM analysis and during the pandemic. Thus, thesignificant finding of this study needs to be viewed with caution until furtherresearch is carried out. Nonetheless, this result provides unique contributionsin terms of highlighting the crucial role of cancer-related communication forpartners with cancer. This suggests that the less cancer-related communicationin partners with cancer may be connected to reports of higher cancer-relateddistress from their partners. It is also possible that this result indicates theneed for interventions aimed at increasing cancer-related communication inpatients with cancer to decrease cancer-related distress. Oncology literaturesuggests that higher levels of dyadic cancer-related distress were associatedwith higher levels of problematic health issues for the caregiver, anxiety anddepression, relationship dissatisfaction, lack of family support, and caregivingburden  samplehomogeneity , (b) methodologicallimitations, and sample size. Future studies should use mixed methods, qualitativelytapping into meaningful individual experiences, to deeply understand the contexts ofcouples with cancer. In addition, a larger sample size would promote validity andgeneralizability. Furthermore, rather than objective observational measures, weutilized self-report surveys, which are always subject to important limitations. Lastly,the results must be interpreted cautiously due to the potential limitations of usingpanel data including interviewer effects, measurement errors, and prestige bias.Patients with cancer often report that their most important relationship is withtheir caregiver—who is most often their romantic partner .Given the importance of this relationship for cancer patients, the findings provideadditional support for studying cancer through a dyadic lens rather than as anindividual experience. Clinicians should seek to work with both partners andconsider both functional and dysfunctional adaptive processes utilized for copingwith this strenuous life event. In addition, clinicians should make efforts toincorporate partners of patients with cancer into the treatment plan and recommendtherapy sessions regularly. Failing to account for the shared experience of canceron couples will likely result in ongoing reports of unmet psychosocial needs andheightened distress among patients and their partners. These findings highlight theimportance of attending to the mentioned gap and are beneficial to couples andtherapists in traditional and integrated behavioral health care  settings, where there is a limited interaction time withpatients. Thus, it is crucial to identify and prioritize which adaptive behaviors may be useful for couples regarding theircancer-related distress.This study provides an opportunity for researchers and health care providers tobroaden their perspective and consider couples facing cancer from a morecomprehensive approach through the VSA model . TheseeUtilizing a dyadic quantitative approach through APIM , thecurrent study aimed to capture the associations among links between cancer-relatedcommunication and cancer-related distress in couples with cancer in the time ofCOVID-19. Findings from this study are critical to ensuring psychosocial–spiritualcare that will meet the needs of couples with cancer and their cancer-relateddistress. The findings underscore the importance of assessing both patients’ andpartners’ adaptive processes such as cancer-related communication and alsocancer-related distress in couples with cancer during the pandemic. Overall, thesefindings highlight the importance of taking a dyadic perspective when studying theadaptive processes with cancer-related distress in couples with cancer during astressful event such as pandemic.


Altered interoception, or the processing of bodily signals, has been argued to play a role in the development and maintenance of substance use disorders (SUD). Therefore, interoceptive interventions focusing on bodily awareness, such as mindfulness meditation, may improve treatment outcomes for individuals with SUD. Here we review: (1) subjective, behavioral and brain evidence for altered interoceptive processing in SUD, focusing on insular and anterior cingulate cortices , key regions for interoceptive processing; (2) research highlighting links between mindfulness and brain function; and (3) extant brain research investigating mindfulness-based interventions in SUD. SUD tend to be characterized by heightened INS and ACC responses to drug cues but blunted interoceptive awareness and attenuated INS and ACC responses during tasks involving bodily attention and/or perturbations. In contrast, mindfulness interventions in healthy individuals are linked to enhanced INS and ACC responses and heightened interoceptive awareness. It is crucial for future research to identify: (1) whether mindfulness-based treatments are efficacious across substance classes; (2) what particular approaches and dosages show the largest effect sizes in enhancing INS and ACC function to non-drug stimuli and reducing responsivity to substance cues, thereby improving SUD treatment outcomes (reducing drug craving and relapse). In 2019, a reported 20.4 million United States citizens  aged 12 or older were diagnosed with at least one substance use disorder (SUD) ,4. High Interoception refers to the process of sensing the internal physiological state of the body by receiving and integrating body-relevant signals with external stimuli . ThroughThe insular cortex (INS) has been characterized as the ‘hub’ of interoception . The posIndividual differences in IA are suggested to be important for how one experiences and responds to internal sensations, with greater IA linked to heightened intensity of physical and emotional sensations . HeartbeInteroception is thought to provide information that influences an individual’s decision to approach or avoid stimuli in the environment with the aim of achieving equilibrium. Dysfunction in interoceptive brain regions may provide a blunted experience of bodily-relevant signals, leading to an inaccurate representation of the bodily state, referred to as a body prediction error ,25,26,27Reduced IA has been demonstrated among individuals meeting criteria for an alcohol use disorder (iAUD) using a behavioral heartbeat perception test. The Schandry task is a widely used mental tracking paradigm in which participants are instructed to silently count their heartbeats across trials of varying lengths and IA is calculated using the participant’s reported versus actual number of heartbeats recorded using electrocardiogram. Of note, the validity of the Schandry task has recently been called into question (see  for moreThe cold pressor task (CPT) is an additional behavioral paradigm used to assess interoceptive responsivity to a physical stressor in which participants are asked to submerge their hand in a cold-water bath for an extended period . This taAlterations in interoceptive processing have also been examined among individuals who use alcohol recreationally and iAUD using neuroimaging techniques. Alcohol use among first-year college students was monitored over the course of a year and progression from moderate to heavy drinking, and increased frequency of alcohol-related problems including experiencing hangovers or memory black-outs, feeling sick, missing class, or impaired performance at school, were linked to baseline hyperactivation in INS, ACC, caudate, and orbitofrontal cortex activation to alcohol images . Thus, hMoreover, INS activity was identified as potentially contributing to continuance of heavy drinking among non-treatment seeking iAUD . GreaterInteroceptive processing has also been examined among individuals who use stimulants such as methamphetamine and cocaine. Discrepant patterns of brain activation in response to a variety of interoceptive stimuli  have been observed among these individuals in comparison to CTL. Using a visceral interoceptive awareness task in which participants were instructed to attend to heartbeat sensations, stomach sensations, or an external visual cue, individuals with methamphetamine use disorder (iMUD) showed blunted anterior/middle INS activation during interoceptive (heartbeat and stomach) trials relative to CTL . DespiteChronic iMUD abstinent for approximately 1 month also show lower INS, thalamus, and striatum responses than CTL to positive gentle tactile stimulation of mechano-receptive c-fibers, which project to anterior INS via the thalamus for interoceptive processing, found in palm and forearm skin . In a reResponsivity to pleasant and aversive interoceptive stimuli has also been examined among individuals who use stimulants  recreationally, as a predictor of transition to problematic substance use (PSU: 2+ DSM-IV criteria of abuse and/or dependence) ,41. YounOther investigations have reported reduced INS activation among individuals meeting DSM-IV criteria for methamphetamine abuse, compared to CTL, while viewing threatening or fearful images . AlthougAmong individuals who use nicotine, interoception has predominantly been examined in relation to cue-induced craving and relapse. Recently abstinent individuals with nicotine dependence show increased anterior INS functional connectivity to clusters including the precuneus and angular gyrus, regions involved in the default mode network, while viewing smoking cues compared to neutral cues . PreviouComparable findings have been found within female-only samples as well. Females meeting criteria for DSM-IV nicotine dependence demonstrated positive correlations between attentional bias to smoking images and brain activation in INS, amygdala, and hippocampus, potentially signaling an interoceptive representation of smoking and induced craving . In lineInteroception has also been examined among individuals who smoke nicotine using behavioral measures such as a heartbeat tracking and heartbeat discrimination task. Using these tasks, adult non-smokers demonstrated increased IA on the heartbeat-tracking task compared to individuals who reported smoking cigarettes daily for at least 1 year . HoweverOverall, findings from neuroimaging studies provide strong support for altered interoceptive processing among individuals who use nicotine and suggest altered connections between interoceptive regions and regions involved in decision-making, behavioral responses, and emotional processing. Findings from behavioral and self-report data are less robust.Although fewer studies have examined interoception among individuals with opioid use disorder (iOUD), existing research suggests a relationship between brain activity in interoceptive regions and cue-reactivity, craving, and relapse. For instance, iOUD undergoing methadone maintenance treatment (MMT), regardless of dosage, demonstrated reductions in INS, amygdala, and hippocampus, but not OFC or ACC, responsivity to heroin cues  post-methadone administration . These fIndividuals who use cannabis chronically or meet criteria for cannabis use disorder (iCUD) also demonstrate altered functioning in interoceptive regions, however, these alterations appear to differ from the patterns seen in individuals with other SUDs. In contrast to iOUD, iCUD exhibit increased responsivity to cannabis-related stimuli in anterior INS, striatum, and amygdala, and INS activity positively correlates with cannabis craving . IndividFew studies have utilized cold pressor tasks to examine pain sensitivity among individuals who use cannabis and findings have been mixed. For example, differences were not observed between individuals who reported frequent cannabis use (three or more uses per week) and those who reported no cannabis use for pain sensitivity, tolerance, or intensity in response to a CPT . In contThe reviewed literature provides strong neuroimaging evidence for altered brain processing among iSUD in brain regions implicated in interoception including INS, ACC, and thalamus. It is important to note that other interpretations of these findings are possible given the additional roles of INS and ACC in other processes including attention salience and conflict/error detection, respectively ,56. HoweIn conjunction with heightened bottom-up interoceptive processing, there also appears to be evidence for decreased top-down cognitive control processes as illustrated by alterations in frontal regions including IFG and OFC. Behavioral tasks, such as heartbeat detection and cold pressor paradigms, have demonstrated mixed findings for altered responsivity to interoceptive stimuli across drug classes. However, some evidence has been presented to suggest an association between an aversive physical stimulus (cold-pressor) and increased craving and subsequent substance use among iAUD specifically. Taken together, findings suggest that interventions modifying activation within the above-mentioned brain regions may be effective for treating SUD. Mindfulness-based interventions are one such promising avenue for improving disrupted interoceptive processing in iSUD. Below, evidence for altering brain functioning with mindfulness-based practices is outlined and existing studies applying such interventions to treatment for iSUD are reviewed. Over the past 30 years, the scientific community has demonstrated an increasing interest in the Buddhist-founded philosophy and practice of mindfulness. Mindfulness is defined as “the awareness that emerges through paying attention on purpose, in the present moment, and non-judgmentally to the unfolding of experiences moment by moment” . It is cSeveral mindfulness-based interventions (MBI) have been developed including mindfulness-based stress reduction (MBSR), mindfulness-based cognitive therapy (MBCT), mindfulness-oriented recovery enhancement (MORE), and mindfulness-based relapse prevention (MBRP). The latter two, MORE and MBRP, were created specifically for iSUD, however, MBSR and MBCT have been used in the treatment of SUD as well.Originally developed by Dr. Jon Kabat-Zinn, MBSR was created with the intention of improving quality of life for individuals with mental and physical health challenges as well as typical life stressors . The focMBCT was created as a derivative from MBSR . MBCT foMORE was created as a blend of MBSR and MBCT practices with a meditative focus to aid in coping with drug cravings . MORE alLastly, MBRP aims to help individuals increase present-moment awareness and increase self-efficacy ,69. ThisThere is a growing body of literature demonstrating the effects of mindfulness and meditation practice on brain functioning among healthy individuals. These results generally suggest that the practice of mindfulness is associated with functional changes in interoceptive, and cognitive control brain regions shown to be altered within iSUD . A recenSustained changes in functional connectivity have also been found following an 8-week course in meditation with reductions in connectivity between INS and medial PFC (a region of the default mode network involved in repetitive negative thinking), and increased activation in dorsolateral PFC ; in contrast, non-meditating CTL showed strong connectivity between INS and medial PFC . These fAssociations between mindfulness and altered brain activity in response to negative emotional and interoceptive stimuli have also been demonstrated with and without formal mindfulness training. United States Marines who underwent a 20 h mindfulness-based training exhibited attenuated INS and ACC activity while experiencing an aversive interoceptive breathing load compared to baseline . In contResearch indicates that mindfulness-based interventions for SUD lead to significantly fewer days of substance use, reduced craving, and lower risk of relapse ,78. HoweTo the best of our knowledge, neuroimaging techniques have only been utilized following MBI among iSUD in one other study. In that study, iOUD were assigned to receive either 4 weeks of a MBI in addition to treatment as usual (TAU) or TAU only during their first month at an addiction inpatient unit. Patients in the MBI group demonstrated a significant difference in resting-state functional connectivity within the default mode network, showing decreased connections with IFG post-MBI; this reduced IFG-default network connection was linked to greater self-reported mindfulness . Other sMindfulness interventions hold significant promise in improving and maintaining recovery among iSUD. Specifically, by targeting, affective, cognitive, and interoceptive processes, mindfulness interventions may exert significant changes in reward-based learning, experience of negative affect, and craving and reactivity to drug use, all of which are associated with the emergence and maintenance of SUD. However, experimental data not only on the effectiveness of mindfulness-based interventions on SUD, but also the mechanisms and neurocircuitry that underlie it, are limited, and this warrants significant ongoing investigations. First, research is needed to establish that mindfulness-based interventions are efficacious across different substance classes. These efforts would benefit from including not only clinically diverse samples to take the often-observed comorbidity in this population into account, but also the moderating effect of demographic and social background information. Second, because several mindfulness training approaches exist, which practices, at what dosing, and in combination with what other interventions  lead to greater improvements needs to be established. For example, what are the difference in efficacy of mindfulness techniques employing focused attention on physical sensations relative to those focused on non-judgmental acceptance? Third, it will be important to employ multiple levels of analysis, including behavioral, physiological, and neurocircuitry. Fourth, based on previous investigations, the field would benefit from centering interoceptive processing as one of the key disease modifying mechanisms for iSUD. Such studies would be able to establish changes in interoception across levels of analysis, as well as the relationship to clinical and functional outcomes. Specifically, does mindfulness practice change interoceptive awareness and associated neural mechanisms, and does this change in turn mediate outcomes? Such studies will not only give evidence to the usefulness of mindfulness-based intervention in engaging underlying mechanisms in treatment of iSUD, but also identify potential predictors of outcomes, and thus additional targets for optimization of this intervention. Finally, engagement of these targets with augmentation approaches, such as biofeedback, real-time neurofeedback, or transcranial magnetic stimulation will provide evidence with respect to malleability of mechanisms underlying mindfulness, interoception, and SUD, as well as whether such augmentation may be necessary in more severe clinical presentations.The literature reviewed here suggest that disruptions in brains’ interoceptive networks underlie the emergence and maintenance of SUD. Given that mindfulness practice engages similar networks, mindfulness-based interventions are well-poised to exert beneficial outcomes in iSUD on both neural and behavioral level. Indeed, mindfulness-based interventions have been associated with reductions in drug use and craving. In clinical settings, mindfulness may be effective in improving self-awareness and decreasing avoidance of inner states such as bodily sensations, emotions, and thoughts. Research shows that this might be beneficial for the often experienced, drug-use promoting negative affect  in iSUD, which can not only be present due to SUD comorbidities, but also directly result from drug withdrawal. This process may also translate to a reduction in responses to drug craving for iSUD. By learning to observe drug-cued mental and physical events, delaying responses to them, and substituting them with alternative behavioral responses, mindfulness may essentially teach iSUD to allow discomforting drug-related states to arise and dissipate naturally without the need for the drug’s potent effects. This disruption of the drug use cycle may then become self-reinforcing. On the other hand, mindfulness practice may bring about increases in experience of pleasure in non-drug related activities. By learning to be present in, notice, and savor meaningful, positive events, iSUD may come to increasingly approach such events in their daily lives. Nevertheless, research on the clinical application of mindfulness for SUD is in its early stages. Future research will need to identify whether mindfulness-based treatments are efficacious across substance classes, and what particular approaches and dosages show the largest effect sizes in enhancing neural networks disrupted by chronic substance use to improve short-term and long-term outcomes.


A high prevalence of cryptoglandular and Crohn’s perianal fistulas has been reported worldwide, and several surgical options are available for the management of anal fistula, with varying clinical efficacy. However, currently, the available evidence for the effectiveness of these surgical approaches are lacking and of concern in terms of the credibility and strength. The purpose of this study is to evaluate the credibility of the published systematic reviews and meta-analyses that assess the efficacy and safety of the surgical options for cryptoglandular and Crohn’s perianal fistulas through an umbrella review.A systematic search in PubMed, Embase and Cochrane library will be performed from inception to December 2020 without any language restriction. We will include systematic reviews and meta-analyses that investigate the efficacy and safety of surgical approaches in the management of cryptoglandular and Crohn’s perianal fistulas. Two reviewers will independently screen search results through reading the titles or abstracts. Relevant information will be extracted from each eligible systematic review or meta-analysis. Based on random effects model summary estimates along with their p values, 95% prediction intervals, between-study heterogeneity, small-study effects and excess significance, we will classify the evidence from convincing (class I) to weak (class IV). Findings will be summarized using quantitative synthesis combined with a narrative approach. Cryptoglandular and Crohn’s perianal fistulas will be summarized separately. Two authors will independently perform the literature search, data extraction, and quality assessment of each included systematic review and meta-analysis. Any unresolved conflicts or doubts will be resolved by discussion or by consulting a senior author. The risk of bias of the systematic reviews will be assessed using a 16-item Assessment of Multiple Systematic Reviews 2 (AMSTAR2) checklist. The strength of evidence for the included systematic reviews will be classified as "high", "moderate", "low", or "critically low" quality.Ethics approval is not required as we will collect data from the published systematic reviews and meta-analyses without using individual patient data. The results of this umbrella review will be published in a peer-reviewed journal and will be presented at an anorectal disease conference.CRD42020200754. Anal fistula, also named fistula-in-ano, is a benign anorectal disease characterized by abnormal inflammatory communication between the anal canal and the perianal skin caused by infection and injury of perianal region . In EuroCryptoglandular and Crohn’s perianal fistulas are two types of fistula with similar pathophysiology but distinct etiologies. Cryptoglandular fistulas are caused by cryptoglandular infections, which contribute to abscess formation, whereas Crohn’s perianal fistulas are mainly caused by an abnormally activated immune system, which can result in chronic inflammation and deep infection formation.Surgery is the primary treatment option for both conditions, and several surgical techniques have been used with varying clinical efficacy in terms of recurrence rate and other postoperative complication rate reported in literatures –11. In pAt present, the surgical approaches for patients with anal fistula include fistulotomy, seton, video-assisted anal fistula treatment (VAAFT), autologous adipose-derived stem cells , mucosal advancement flap, ligation of intersphincteric fistula tract (LIFT), fibrin sealant, biologic fistula plugs, synthetic fistula plug and fistula tract laser closure –15. TheySeveral randomized controlled trials, clinical controlled trials, comparative studies, and subsequently systematic reviews and meta-analyses, have been conducted to investigate the efficacy of surgical-related interventions on the clinical outcomes in patients with both cryptoglandular and Crohn’s perianal fistulas –20. Nevewww.crd.york.ac.uk/prospero) under the registration number CRD42020200754. The review is scheduled to be conducted between December 2020 and October 2021.The umbrella review will be performed according to the predesigned protocol that has been developed based on the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) guidelines  S1 Tabl. This prWe will conduct a comprehensive review of all available reviews on the topic using the methodology described in previous reports –24. UmbrWe will conduct a systematic search of five databases, including PubMed, the Cochrane Database of Systematic Reviews, Embase, Web of Science, and Google Scholar, until December 2020. All systematic reviews, meta-analyses, and pooled analyses that investigate the efficacy and safety of surgical approaches in the management of cryptoglandular and Crohn’s perianal fistulas will be included.www.crd.york.ac.uk/prospero and www.inplasy.com). Unpublished grey literature will not be considered. We will not impose any language restrictions. A manual search of reference lists from relevant studies will be conducted.Our search strategy will be comprised of the three elements listed below: (1) clinical condition ; (2) interventions ; and (3) study design , with variations for various databases . We willEndNote X9 software  will be used to remove duplicates and screen for literature. Two authors (ZM and QF) will independently select the potentially relevant systematic reviews by reading through their titles and abstracts. Any disagreements will be discussed with a senior author (XY) until consensus is reached. When titles and abstracts are insufficient to determine whether to include or exclude reviews, we will download full texts to determine eligibility.Systematic reviews of randomized controlled trials and controlled clinical trials investigating the efficacy of surgery-related interventions for patients with cryptoglandular or Crohn’s perianal fistulas will be included. Cryptoglandular and Crohn’s perianal fistulas will be summarized separately. Because we only focus on surgical treatment interventions, systematic reviews of non-interventional studies  will be excluded. Finally, only systematic reviews with quantitative data synthesis will be considered. The systematic reviews will be excluded if study-level effect estimates with 95% CIs cannot be obtained. Based on the umbrella review methodology, when multiple systematic reviews provide duplicated datasets for the same comparison, the systematic review with the greatest number of studies providing study-level effect estimates is retained for further analysis . The folParticipants are those who have an established diagnosis of cryptoglandular or Crohn’s perianal fistulas based on accepted criteria , without limits on age or gender.Surgical interventions  for the treatment of cryptoglandular or Crohn’s perianal fistulas, such as ligation of intersphincteric fistula tract, fistulectomy, fistulotomy, rectal advancement flap, anal fistula plug, fibrin glue, seton drainage and mesenchymal stromal cells, will be included. Our umbrella review will primarily focus on randomized controlled trials and controlled clinical trials of the aforementioned individual interventions in the treatment of anal fistula, and the interventions of the control group involve the commonly used procedures for anal fistula that are not limited to a specific one.Systematic reviews and meta-analyses that report one or more of the following types of outcome measures will be considered:1. Surgical related symptoms or conditions include: surgical time, postoperative pain, postoperative complications or adverse events such as postoperative pain, bleeding, wound swelling, urinary retention, delayed healing, or healing rate.2. Anal fistula recurrence: recurrence of anal fistula symptoms or clinical manifestations at the end of follow-up.3. Patient’s satisfaction and functional outcomes: patient quality of life, incontinence rate, time needed for return to work or usual activities and duration of hospital stay.We will develop a standardized form for extracting data from each systematic review. Two authors will collect the variables listed below and cross-check the accuracy of the data. Each primary study will yield the following information: first author, year of publication, number of included studies, population involved , type of surgical interventions, outcome reported, sample size, and study-specific standardized mean differences or weighed mean differences with corresponding 95% CIs for continuous outcomes , or relative risks/hazard ratios/odd ratios with corresponding 95% CIs for categorical outcomes .Methodological quality of the included systematic reviews will be assessed by two authors using the Assessment of Multiple Systematic Reviews 2  tool, a 16-item checklist used to critically rate the quality of an individual systematic review as high, moderate, low and critically low based on the total score of the AMSTAR2.For each intervention and outcome measure, we will re-estimate the summary effect and the 95% CI using random effects model with the DerSimonian-Laird (inverse variance) method by combining effect estimates from previously published meta-analyses after removing duplicates. Furthermore, we will compare the direction, level of statistical significance and overlapping confidence interval for the summary effects of the association for overlapping meta-analyses that investigate the same relationships between surgical interventions and clinical outcomes in the same clinical setting, In general, we will select the most updated one for further evaluation.Stratified analyses will also be performed, with estimates summarized by disease type , study design , total sample size (<500 vs. ≥500), follow-up period (<12 months vs ≥12 months), and the combined surgical and medical treatment for Crohn’s anal fistula (yes vs. no) across studies.2 statistic [2 statistic exceeds 25%, 50%, and 75%, the heterogeneity is considered low, substantial and considerable, respectively.The χ2-based Cochran’s Q test  and Higgtatistic  will be To account for between-study heterogeneity, the prediction intervals (PIs) and 95% CIs, which are used to show the expected range of true effect estimates in future studies, will also be calculated for the summary random effect estimates .To investigate small study effects, Egger’s regression asymmetry test will be used . In geneThe Ioannidis’ excess significance test will be evaluated by determining whether the results of the observed number of studies (O) included in each meta-analysis  differ significantly from the expected number of studies with significant results (E). To estimate the statistical power of each individual study, we will use the effect size of the largest study  in the included meta-analysis . Excess We will use the following criteria to evaluate the credibility of the included meta-analyses:−6), no evidence of small-study effects, no evidence of excess of significance, 95% prediction intervals excluding the null value and not large between-study heterogeneity (I2 < 50%);> 1000 cases, significant combined associations for random-effects calculation , and the largest study with 95% CI excluding the null value;−3);> 1000 cases and significant combined associations for random-effects calculation .By incorporating evidence from published systematic reviews and meta-analyses, we will provide a comprehensive overview of the summary effects of various surgery-related interventions on the clinical efficacy of patients with cryptoglandular and Crohn’s perianal fistulas.With the increasing prevalence of perianal fistulas of both cryptoglandular and Crohn’s disease origin, the general population bears a significant socioeconomic burden. We will assess the level of evidence for the efficacy of common anal fistula surgical techniques used worldwide, such as ligation of the intersphincteric fistula tract, fistulectomy, fistulotomy, rectal advancement flap, anal fistula plug, fibrin glue, seton drainage, and mesenchymal stromal cells.To the best of our knowledge, this is the first comprehensive review that summarizes the efficacy of various surgical techniques for cryptoglandular and Crohn’s perianal fistulas. When sufficient high-quality data are available, we will stratify our comparisons by type of anal fistula, which will provide surgeons with high-level evidence to help them choose the best surgical technique for these patients. To account for between-study heterogeneity and provide more objective and convincing results in a future study examining the same association, 95% prediction intervals will be estimated. Furthermore, we will only include data from previously published systematic reviews and meta-analyses, which will have a higher level of evidence for this topic.When we incorporate the high-level evidence of surgery interventions for perianal fistula from our findings, we can provide important information on clinical guidelines and therapeutic selection for those patients, such as the benefits of LIFT procedure and rectal advancement flap on the postoperative functional outcomes. Our umbrella review will have limitations as well. The included systematic reviews vary in their heterogeneity and quality. As a result, random effects meta-reanalyses will be performed for each outcome. In addition, we will use the AMSTAR 2 checklist to assess the quality of each included study.The findings of this umbrella review will be published in a peer-reviewed journal, and we believe that the result will benefit anorectal surgeons, patients and policy-makers.S1 Table(DOC)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.


Unraveling the cellular and molecular mechanisms of spinal cord injury is fundamental for our possibility to develop successful therapeutic approaches. These approaches need to address the issues of the emergence of a non-permissive environment for axonal growth in the spinal cord, in combination with a failure of injured neurons to mount an effective regeneration program. Experimental in vivo models are of critical importance for exploring the potential clinical relevance of mechanistic findings and therapeutic innovations. However, the highly complex organization of the spinal cord, comprising multiple types of neurons, which form local neural networks, as well as short and long-ranging ascending or descending pathways, complicates detailed dissection of mechanistic processes, as well as identification/verification of therapeutic targets. Inducing different types of dorsal root injury at specific proximo-distal locations provide opportunities to distinguish key components underlying spinal cord regeneration failure. Crushing or cutting the dorsal root allows detailed analysis of the regeneration program of the sensory neurons, as well as of the glial response at the dorsal root-spinal cord interface without direct trauma to the spinal cord. At the same time, a lesion at this interface creates a localized injury of the spinal cord itself, but with an initial neuronal injury affecting only the axons of dorsal root ganglion neurons, and still a glial cell response closely resembling the one seen after direct spinal cord injury. In this review, we provide examples of previous research on dorsal root injury models and how these models can help future exploration of mechanisms and potential therapies for spinal cord injury repair. Dorsal root ganglion (DRG) neurons are pseudounipolar cells with a single process, bifurcating in a peripherally and a centrally directed branch. The latter initially shares the typical features of peripheral nerve tissue with Schwann cells and basement lamina. Just outside the spinal cord, at the dorsal root transitional/entry zone (DRTZ/DREZ), dorsal root axons encounter central glia and course through channels between astrocytes ,2,3. MyeDisorders that damage dorsal roots include compression, , infections, autoimmune mechanisms, metabolic disorder, neurotoxic agents, and trauma. Clinically, the most important type of traumatic injury of the dorsal root is spinal root avulsion, a forceful, longitudinal traction of spinal nerve roots, interrupting their connections with the spinal cord. This condition may occur during complicated delivery, from a fall from a high height, or in a traffic accident, and most commonly affects spinal nerve roots innervating the upper extremity, i.e., brachial plexus avulsion.Root avulsion injuries in experimental animals are typically performed by a surgical approach after exposure of the spinal cord and appropriate root entry regions to achieve standardized and reproducible lesions. However, in clinical root avulsion injuries, the forces that pull the roots from the spinal cord are usually exercised from outside the vertebral canal. The lesion is variable in location and extent of injury, and with possible differences in, for example, the consequences for the regional vascular supply. In terms of location, clinical avulsion injuries can occur distal (postganglionic injury) or proximal (preganglionic injury) to the dorsal root ganglia . The posSpinal root avulsion injuries typically affect ventral and well as dorsal roots, causing paralysis of denervated muscles, loss of sensory and autonomic function, and, most often, neuropathic pain. Cauda equine syndrome, which encompasses avulsion of lumbosacral roots, also leads to weakness or paralysis of muscles controlling micturition, defecation, and sexual functions. Surgical treatment of spinal root avulsion offers a possibility for partial functional restoration of motor function by reinnervation of proximally located muscles, but clinically efficient treatment for restoring sensory function is thus far not available ,14. ThusHere, we discuss injury (axotomy) of dorsal roots as an attractive experimental model to address key aspects of spinal cord injury repair in vivo. Already Ramon y Cajal made the conclusion from his experiment that whereas injury to the peripheral branch of dorsal root ganglia is followed by axonal regeneration and reconnection with peripheral targets, injury to the central branch results in abortive axonal growth . A detaiThus, axotomy (crushing or cutting) of the dorsal root in its peripheral compartment allows investigation of how axonal extension can be promoted, first along with Schwann cells, and thereafter when encountering central glia, which reacts to the injury at a distance, i.e., without damage to the spinal cord itself. On the other hand, the most centrally located dorsal root injury, dorsal root avulsion, will damage the DREZ, including its central glial component, and thereby constitute a true CNS injury, but isolated to the dorsal root axons and their immediate surroundings . In thisDuring development, dorsal root sensory axons enter the spinal cord in temporally successive waves . A transThe regulated sensory axon ingrowth appears to be dependent on semaphorin ,27 and nAn appropriate cell body response, comprising a set of so-called regeneration associated genes (RAGs) , combineAlthough DRG is composed of phenotypically diverse neurons, they appear to undergo a uniform transcriptional program after peripheral nerve injury, induced by cyclic AMP-dependent transcription factor (ATF-3) . WhetherInterventions, e.g., the use of growth factors or cell-based approaches to promote regeneration of dorsal root axons, are likely to result in differential effects depending on neuronal subtype-specific growth factor receptor pattern and cell-matrix interactions signaling systems see .The potential of DRG neurons to mount an efficient regenerative response after dorsal root injury is shown by a so-called conditioning lesion, i.e., an injury to the peripheral sensory axons. This intervention, which is typically performed one to two weeks prior to injury to the central processes of the same sensory neurons induces RAGs in DRG neurons and stimulates growth supportive interactions between dorsal root axons and associated non-neuronal cells, thereby promoting elongation of injured dorsal root axons . The conA conditioning peripheral nerve lesion by itself may allow spinal cord entry of a limited number of injured dorsal root axons , which aAlthough much of the regeneration-associated neuronal changes occur in the cell bodies of the affected neurons, the importance of a local regeneration supporting metabolic system, proposed already long ago ,52, is nExtracellular  or gene Growth factor-mediated growth of dorsal root axons appears to act on intracellular pathways, which at least in part share those implicated in the conditioning lesion response , althougPTEN (phosphatase and tensin homolog deleted on chromosome 10) has emerged as promising target to recover the intrinsic growth capacity of adult neurons. PTEN inhibits phosphoinositide 3-kinase (PI3-K)/Akt/mTOR pathway, which is critical for sustained axonal elongation. Activation of PTEN also appears to contribute to myelin-associated growth inhibition . BlockinTo allow elongation of regenerating axons, microtubules behind the leading edge need to be stabilized . StudiesThe mechanisms for induction and maintenance of a neuronal regeneration program, including its regulation at the gene level, were extensively reviewed . From haFollowing spinal cord injury, there are marked changes in the expression of non-coding RNAs, which appear to be associated with the pathophysiological events and the subsequent repair mechanisms . MiR-155Epigenetic modification has recently emerged as a significant factor influencing the outcome after neural injury . SuccessMicroglia and astrocytes play critical roles in the pathophysiology and repair after spinal cord injury and are, therefore, potential targets for therapy . ReactivPrevious studies reported that a conditioning lesion combined with enzymatic degradation of chondroitinase sulfate proteoglycans with chondroitinase ABC , their rThe limited effect on sensory axon spinal cord ingrowth by pharmacological interventions targeting the DREZ may be related to the observation that regenerating sensory axons form synapse-like contacts with non-neuronal cells, possibly NG2-positive glia, rather than traversing the PNS-CNS boundary and enter the spinal cord ,123,124.During Wallerian degeneration of peripheral nerves, Schwann cells in cooperation with fibroblasts and immune cells, clear disintegrating axons and myelin in preparation for a growth permissive pathway for axon regeneration. In contrast, myelin debris arising from Wallerian degeneration in the central nervous system remains for long periods of time ,127. In The long-term lingering of myelin debris after spinal cord injury is probably the result of an insufficient activation of the macrophage/microglial program required for rapid and complete myelin degradation ,129,130.Small rodents have dominated experimental studies on spinal cord injury for decades, but, as often recognized, translation from these studies to humans is frequently difficult. Early studies of Wallerian degeneration in the spinal cord or animals with considerably larger myelinated axons than what is the case in the small rodents have shown the emergence and long-term presence of abnormal profiles, such as the “myelinoclasts” in monkeys . SimilarDorsal root avulsion has consequences not only for spinal cord glia and immune cells but also results in degeneration of postsynaptic neurons in the dorsal as well as ventral horn . Loss ofConversely, there is a loss of previously existing postsynaptic targets, causing presynaptic neurons to degenerate . These processes effectively impair the possibility for potentially regenerating axons to restore functionally useful connections and for replacement of lost connections by circuit rewiring . Dorsal Cell-based bridges, acellular bridges, and their combinations are attractive strategies for the repair of the spinal cord and dorsal root injury. The overall purpose of these strategies is to promote functional recovery by (i) survival/growth support for intrinsic cells,(ii) disease modification to facilitate endogenous repair, and (iii) replacement of lost cells or introduction of relay cells. The implementation of these strategies for spinal cord injury is discussed by Guo . Lin et Early studies aimed to provide a bridge for regenerating dorsal root axons into the spinal cord by exploiting, for example, Schwann cells , or actiWith the purpose of probing the greater capacity for immature neurons to regenerate after injury, human embryonic/fetal dorsal root ganglion cells were implanted into the cavity of extirpated rodent DRGs . SensoryOlfactory ensheathing cells (OECs) are CNS glia, ensheathing non-myelinated olfactory nerve axons in the intact nervous system, and able to serve as a cellular substrate for regenerating axons. OEC implants readily integrate into non-olfactory CNS regions and have been shown to be able to provide a pathway for sensory axon growth into the spinal cord and restore sensorimotor function after spinal root avulsion .Stem cell-based transplants at the DREZ could serve as facilitators for entry of dorsal root axons or as neuronal relays to interconnect dorsal root axons in the PNS compartment with spinal cord neurons . Since bHuman neural progenitor cell implants were shown to support sensory axon ingrowth and partial recovery of sensory function after dorsal root avulsion, seemingly by creating channels, i.e., acting as growth facilitators . When suIn addition, to provide growth-supporting substrate, OEC or stem cell implants are likely to release growth supportive agents and presumably modify immune responses in a way that does not antagonize sensory axon growth across the DREZ. Clarifying the mechanisms underlying these approaches and explore the way to improve their efficiency is thus likely to contribute to the exploitation of cell-based therapies in direct spinal cord injury, e.g., by the administration of exosomes containing defined growth supporting and/or disease-modifying components ,159.Pioneering studies by Aguayo and collaborators demonstrated that injured CNS neurons are able to elongate for long distances within a peripheral nerve graft ,161,162.The application of bridges that circumvent a severely damaged spinal cord area would be a relevant option for restoring descending control of specific spinal cord functions. To make the axons elongating in the bridge enter the spinal cord, the graft-cord barrier issue needs to be resolved. This situation has similarities to the growth repelling barrier facing injured dorsal root axons at the DREZ. Approaches, which are discussed above to promote dorsal root regeneration into the spinal cord, are thus likely to be relevant also for achieving entry of axons, which have grown through a bridging graft. One additional, interesting aspect in this context is that the intact DREZ does not appear to exhibit a growth repellent barrier . Figure 3D bioprinting has rapidly developed as a highly attractive technology for biomimetic implants that is able to support neuronal survival, counteract disease driving processes and support functional repair following spinal cord injury . Based oInjuries that interrupt dorsal root axons result in loss of sensorimotor functions and often neuropathic pain, symptoms which are usually most serious following root avulsion injury. Injured dorsal root axons are unable to restore lost connections due to insufficient regeneration performance in combination with the encounter of a growth repelling CNS environment, i.e., factors which are closely similar to those that underlie the regeneration failure after direct spinal cord injury. Dorsal root injury offers attractive experimental models to determine key mechanisms in these processes in vivo, their exploitation for the development of novel therapeutic strategies, and their translation to a clinical setting for dorsal root injuries.Dorsal root avulsion, which constitutes a longitudinal spinal cord injury, is of particular relevance in the broader context of spinal cord injury A successful strategy to tackle dorsal root avulsion injury most likely requires a combinatorial approach, applied in an appropriate spatial and temporal manner. We envision such a strategy might include the following actions. (i) Cell-based approaches, e.g., via exosomes derived from primed stem cells or as bioprinted constructs, may be suitable for promoting tissue repair at the injury site., as well as for creating pathways across the DREZ. (ii) Intrathecal administration of agents that specifically counteract non-neuronal axon growth inhibitors at the DREZ, as well as along ascending sensory pathways, are likely to be needed as additive measures. (iii) Application of gene regulatory tools to initiate and achieve sustained axonal growth by all subpopulations of dorsal root ganglion neurons. The dorsal root-spinal cord unit provides a favorable platform for assessing the outcome of these interventions, individually as well as in various combinations, initially in small rodent models and subsequently translated to larger species prior to clinical trials in humans.