Septic shock as a trigger of arterial stress-induced premature senescence: A new pathway involved in the post sepsis long-term cardiovascular complications

Sepsis and post-sepsis syndrome: a multisystem challenge requiring comprehensive care and management-a review

Sepsis, a medical emergency with high mortality rates, demands comprehensive care spanning from early identification to patient rehabilitation. The sepsis survival chain encompasses early recognition, severity assessment, activation of emergency services, initial antimicrobial therapy, hemodynamic stabilization, and integrated rehabilitation. These interconnected steps are critical to reducing morbidity and mortality. Despite advancements in international guidelines, adherence remains limited, contributing to a significant disease burden. Beyond its acute phase, post-sepsis syndrome (PSS) is characterized by long-term immune dysregulation, chronic inflammation, and metabolic dysfunction, predisposing survivors to recurrent infections, cardiovascular disease, and neurocognitive decline. Mitochondrial dysfunction and epigenetic modifications play a central role in prolonged immunosuppression, impairing adaptive and innate immune responses. Sepsis-induced organ dysfunction impacts multiple systems, including the brain, heart, and kidneys. In the brain, it is associated with neuroinflammation, blood-brain barrier dysfunction, and the accumulation of neurotoxic proteins, leading to acute and chronic cognitive impairment. Myocardial dysfunction involves inflammatory mediators such as TNF-α and IL-6, while sepsis-associated acute kidney injury (SA-AKI) arises from hypoperfusion and inflammation, heightening the risk of progression to chronic kidney disease. Additionally, immune alterations such as neutrophil dysfunction, continuous platelet activation, and suppressed antitumoral responses contribute to increased infection risk and long-term complications. Timely and targeted interventions, including antimicrobial therapy, cytokine modulation, immune restoration, metabolic support, and structured rehabilitation strategies, are pivotal for improving outcomes. However, financial and infrastructural limitations in low-resource settings pose significant barriers to effective sepsis management. Precision medicine, AI-driven early warning systems, and optimized referral networks can enhance early detection and personalized treatments. Promoting public and professional awareness of sepsis, strengthening multidisciplinary post-sepsis care, and integrating long-term follow-up programs are imperative priorities for reducing mortality and improving the quality of life in sepsis survivors.

Identifying novel aging-related diagnostic and prognostic models and aging-targeted drugs for sepsis patients

Sepsis is defined as a dysfunctional, life-threatening response to infection leading to multiorgan dysfunction and failure. During the past decade, studies have highlighted the relationship between sepsis and aging. However, the role of aging-related mechanisms in the progression and prognosis of sepsis remains unclear. In the present study, we divided sepsis patients into High- and Low-aging groups based on the gene set variation analysis (GSVA) scores of GOBP-AGING gene set. Sepsis patients in the high-aging group exhibited higher levels of infiltration of innate immune cells, lower levels of infiltration of adaptive immune cells, and a worse prognosis than those in the Low-aging group. Additionally, the MPO to MME ratio (MPO/MME) appears to be an effective biomarker for predicting the prognosis of sepsis patients. Moreover, ARG1/SEC63 and ARG1/CDKN1C appear to be effective and robust biomarkers for the early diagnosis of sepsis patients. Finally, we found that thalidomide (TAL) significantly ameliorated LPS induced inflammation and organ injury and attenuated LPS induced cellular senescence in lung and kidney. Overall, this study provides new insights into the heterogeneity of sepsis, reveals the vital role of aging-related markers in the prognosis and diagnosis of sepsis and demonstrates that TAL is a novel aging-targeted drug for sepsis patients by attenuating LPS induced cellular senescence.

CECAL SLURRY AS AN ALTERNATIVE MODEL TO CECAL LIGATION AND PUNCTURE FOR THE STUDY OF SEPSIS-INDUCED CARDIOVASCULAR DYSFUNCTION

ABSTRACT

Sepsis is a life-threatening condition widely studied by animal models. Cecal ligation and puncture (CLP) is still regarded as the gold standard model for sepsis. However, CLP has limitations due to its invasiveness and variability. Cecal slurry (CS) model is a nonsurgical and thus less invasive alternative. However, the lack of standardization of the CS model in the literature limits its practical application. Additionally, it is not well studied whether CS model reproduces septic cardiovascular dysfunction in rats, which is a crucial issue in septic patients. Thus, this study aimed to standardize the CS model in Wistar rats and evaluate sepsis-induced cardiovascular dysfunction compared to CLP. Our results showed that CS model induced important features of sepsis cardiovascular dysfunction 24 h after its onset, such as hypotension, tachycardia, and decreased contractile response to vasoconstrictors both in vivo and ex vivo as well changes in renal blood flow. Increases in blood lactate, AST, ALT, creatinine, and urea indicated organ dysfunction. CS model also induced increased production of nitric oxide metabolites and bacterial spread to tissues. CS model causes less animal suffering, it is a nonsurgical model, and, more importantly, it replicates the cardiovascular dysfunction induced by sepsis with better homogeneity than CLP. Therefore, CS model serves as an alternative and possibly as a better model for sepsis research.

The role of pulse wave analysis indexes for critically ill patients: a narrative review

Objective.Arterial pulse wave analysis (PWA) is now established as a powerful tool to investigate the cardiovascular system, and several clinical studies have shown how PWA can provide valuable prognostic information over and beyond traditional cardiovascular risk factors. Typically these techniques are applied to chronic conditions, such as hypertension or aging, to monitor the slow structural changes of the vascular system which lead to important alterations of the arterial PW. However, their application to acute critical illness is not currently widespread, probably because of the high hemodynamic instability and acute dynamic alterations affecting the cardiovascular system of these patients.Approach.In this work we propose a review of the physiological and methodological basis of PWA, describing how it can be used to provide insights into arterial structure and function, cardiovascular biomechanical properties, and to derive information on wave propagation and reflection.Main results.The applicability of these techniques to acute critical illness, especially septic shock, is extensively discussed, highlighting the feasibility of their use in acute critical patients and their role in optimizing therapy administration and hemodynamic monitoring.Significance.The potential for the clinical use of these techniques lies in the ease of computation and availability of arterial blood pressure signals, as invasive arterial lines are commonly used in these patients. We hope that the concepts illustrated in the present review will soon be translated into clinical practice.

Central blood pressure estimation from radial artery in septic shock

Pulse Pressure (PP) increases progressively from the central arteries to the peripheral arteries, this well-established hemodynamic phenomenon is called pulse pressure amplification (PPA). Acute critically ill patients may be subject to profound alterations of cardiac and arterial properties. However, blood pressure (BP) is commonly monitored from one peripheral catheter only. The estimation of a central pressure is pivotal to investigate the PPA and thus to track changes in pulse wave propagation and to identify vascular dysfunctions. We analyzed the data from an animal experiment of polymicrobial septic shock to verify if the estimate of central BP from the radial artery BP waveform only permits the identification of the septic-induced alterations in pulse wave transmission. The method consists of an adaptive transfer function based on a model of wave transmission and reflection, and characterized by two parameters, the reflection coefficient Γ and the time delay Td. The average root mean square error (RMSE) was assessed at each experimental time point, baseline: 3.5 (3.2, 3.9) mmHg, after septic shock development: 5.0 (3.6, 8.0) mmHg, after resuscitation: 12.3 (8.3, 16.7) mmHg, showing a good level of agreement with the measured waveforms.

Wave Separation Analysis to Assess Cardiovascular Alterations Induced by Sepsis

OBJECTIVE

Sepsis induces a severe decompensation of arterial and cardiac functional properties, leading to important modifications of arterial blood pressure (ABP) waveform, not resolved by recommended therapy, as shown by previous works. The aim of this study is to quantify the changes in ABP waveform morphology and wave reflections during a long-term swine experiment of polymicrobial sepsis and resuscitation, to deepen the understanding of the cardiovascular response to standard resuscitation therapy.

METHODS

We analyzed 14 pigs: polymicrobial sepsis was induced in 9 pigs followed by standard resuscitation and 5 pigs were treated as sham controls. Septic animals were studied at baseline (T1), after sepsis development (T2), and after 24 h (T3) and 48 h (T4) of therapy administration, and sham controls at the same time points. ABP and arterial blood flow were measured in the left and right carotid artery, respectively. Pulse wave analysis and wave separation techniques were used to estimate arterial input impedance, carotid characteristic impedance, forward and backward waves, indices of wave reflections such as reflection magnitude and reflection index, and augmentation index.

RESULTS

Sepsis led to an acute alteration of ABP waveform passing from type A to type B or C; consistently, the reflection phenomena were significantly reduced. The resuscitation was successful in reaching targeted hemodynamic stability, but it failed in restoring a physiological blood propagation and reflection.

CONCLUSION

Septic pigs persistently showed altered reflected waves even after 48 hours of successful therapy according to guidelines, suggesting a persistent hidden cardiovascular disorder.

SIGNIFICANCE

The proposed indices may be useful to unravel the complex cardiovascular response to therapy administration in septic patients and could potentially be used for risk stratification of patient deterioration. Whether alterations of blood propagation and reflection contribute to persisting organ dysfunction after hemodynamic stabilization should be further investigated.

Activation of senescence in critically ill patients: mechanisms, consequences and therapeutic opportunities

Whereas aging is a whole-organism process, senescence is a cell mechanism that can be triggered by several stimuli. There is increasing evidence that critical conditions activate cell senescence programs irrespective of patient's age. In this review, we briefly describe the basic senescence pathways and the consequences of their activation in critically ill patients. The available evidence suggests a paradigm in which activation of senescence can be beneficial in the short term by rendering cells resistant to apoptosis, but also detrimental in a late phase by inducing a pro-inflammatory and pro-fibrotic state. Senescence can be a therapeutic target. The use of drugs that eliminate senescent cells (senolytics) or the senescence-associated phenotype (senomorphics) will require monitoring of these cell responses and identification of therapeutic windows to improve the outcome of critically ill patients.

Loss of Pla2r1 decreases cellular senescence and age-related alterations caused by aging and Western diets

Cellular senescence is induced by many stresses including telomere shortening, DNA damage, oxidative, or metabolic stresses. Senescent cells are stably cell cycle arrested and they secrete many factors including cytokines and chemokines. Accumulation of senescent cells promotes many age-related alterations and diseases. In this study, we investigated the role of the pro-senescent phospholipase A2 receptor 1 (PLA2R1) in regulating some age-related alterations in old mice and in mice subjected to a Western diet, whereas aged wild-type mice displayed a decreased ability to regulate their glycemia during glucose and insulin tolerance tests, aged Pla2r1 knockout (KO) mice efficiently regulated their glycemia and displayed fewer signs of aging. Loss of Pla2r1 was also found protective against the deleterious effects of a Western diet. Moreover, these Pla2r1 KO mice were partially protected from diet-induced senescent cell accumulation, steatosis, and fibrosis. Together these results support that Pla2r1 drives several age-related alterations, especially in the liver, arising during aging or through a Western diet.

Contribution of viral and bacterial infections to senescence and immunosenescence

Cellular senescence is a key biological process characterized by irreversible cell cycle arrest. The accumulation of senescent cells creates a pro-inflammatory environment that can negatively affect tissue functions and may promote the development of aging-related diseases. Typical biomarkers related to senescence include senescence-associated β-galactosidase activity, histone H2A.X phosphorylation at serine139 (γH2A.X), and senescence-associated heterochromatin foci (SAHF) with heterochromatin protein 1γ (HP-1γ protein) Moreover, immune cells undergoing senescence, which is known as immunosenescence, can affect innate and adaptative immune functions and may elicit detrimental effects over the host's susceptibility to infectious diseases. Although associations between senescence and pathogens have been reported, clear links between both, and the related molecular mechanisms involved remain to be determined. Furthermore, it remains to be determined whether infections effectively induce senescence, the impact of senescence and immunosenescence over infections, or if both events coincidently share common molecular markers, such as γH2A.X and p53. Here, we review and discuss the most recent reports that describe cellular hallmarks and biomarkers related to senescence in immune and non-immune cells in the context of infections, seeking to better understand their relationships. Related literature was searched in Pubmed and Google Scholar databases with search terms related to the sections and subsections of this review.

Endothelial Senescence and Its Impact on Angiogenesis in Alzheimer's Disease

Endothelial cells are constantly exposed to environmental stress factors that, above a certain threshold, trigger cellular senescence and apoptosis. The altered vascular function affects new vessel formation and endothelial fitness, contributing to the progression of age-related diseases. This narrative review highlights the complex interplay between senescence, oxidative stress, extracellular vesicles, and the extracellular matrix and emphasizes the crucial role of angiogenesis in aging and Alzheimer's disease. The interaction between the vascular and nervous systems is essential for the development of a healthy brain, especially since neurons are exceptionally dependent on nutrients carried by the blood. Therefore, anomalies in the delicate balance between pro- and antiangiogenic factors and the consequences of disrupted angiogenesis, such as misalignment, vascular leakage and disturbed blood flow, are responsible for neurodegeneration. The implications of altered non-productive angiogenesis in Alzheimer's disease due to dysregulated Delta-Notch and VEGF signaling are further explored. Additionally, potential therapeutic strategies such as exercise and caloric restriction to modulate angiogenesis and vascular aging and to mitigate the associated debilitating symptoms are discussed. Moreover, both the roles of extracellular vesicles in stress-induced senescence and as an early detection marker for Alzheimer's disease are considered. The intricate relationship between endothelial senescence and angiogenesis provides valuable insights into the mechanisms underlying angiogenesis-related disorders and opens avenues for future research and therapeutic interventions.

CELLULAR SENESCENCE IMPLICATED IN SEPSIS-INDUCED MUSCLE WEAKNESS AND AMELIORATED WITH METFORMIN

ABSTRACT

Background: Sepsis is a life-threatening medical emergency, frequently complicated with intensive care unit-acquired weakness syndrome (ICU-AW). ICU-AW patients display flaccid weakness of the limbs, especially in the proximal limb muscles. However, little is known regarding its pathogenesis. Here, we aimed to identify the potential signaling pathway involved in ICU-AW regulation and identify a potential therapeutic drug for intervention. Methods: Both in vivo and in vitro septic mice were used. For the in vivo septic mice, either cecum ligation and puncture or intraperitoneal injection of LPS was conducted in mice. The body weight and muscle mass were then measured and recorded. Muscle strength was evaluated by limb grip strength test. The expression of proteins extracted from cells and muscles was checked through Western blot analysis. Quantitative reverse transcription-polymerase chain reaction was carried out to test the transcriptional level of genes. Senescence-associated β-galactosidase (SA-β-gal) staining and Sirius red for collagen staining were conducted. Metformin, as an antiaging agent, was then tested for any attenuation of sepsis-related symptoms. For in vitro sepsis modeling, myoblasts were treated with LPS, analyzed for senescence-related protein expression, and subsequently retested upon metformin treatment. Results: We found that both the weight and strength of muscle were dramatically reduced in cecum ligation and puncture- or LPS-induced septic mice. RNA-seq analysis revealed that various cellular senescent genes were involved in sepsis. In line with this, expression of senescence-related genes, p53 and p21 were both upregulated. Both SA-β-gal and Sirius red for collagen staining were enhanced in tibialis anterior muscles. Notably, inhibition of p53 expression by siRNA prominently reduced the number of SA-β-gal-positive myoblasts upon LPS treatment. This indicated sepsis-induced cellular senescence to be dependent on p53. Consistent with the function of metformin in antiaging, metformin attenuated cellular senescence in both murine myoblasts and skeletal muscles during sepsis. Muscle strength of septic mice was improved upon metformin treatment. Metformin intervention is therefore proposed as a potential therapeutic strategy for ICU-AW. Conclusion: Taken together, we revealed a previously unappreciated linkage between cellular senescence and sepsis-induced muscle weakness and propose metformin as a potential therapeutic drug for the treatment of ICU-AW.

Statins Show Anti-Atherosclerotic Effects by Improving Endothelial Cell Function in a Kawasaki Disease-like Vasculitis Mouse Model

Kawasaki disease (KD) is an acute inflammatory syndrome of unknown etiology that is complicated by cardiovascular sequelae. Chronic inflammation (vasculitis) due to KD might cause vascular cellular senescence and vascular endothelial cell damage, and is a potential cause of atherosclerosis in young adults. This study examined the effect of KD and HMG-CoA inhibitors (statins) on vascular cellular senescence and vascular endothelial cells. Candida albicans water-soluble fraction (CAWS) was administered intraperitoneally to 5-week-old male apolipoprotein E-deficient (ApoE-) mice to induce KD-like vasculitis. The mice were then divided into three groups: control, CAWS, and CAWS+statin groups. Ten weeks after injection, the mice were sacrificed and whole aortic tissue specimens were collected. Endothelial nitric oxide synthase (eNOS) expression in the ascending aortic intima epithelium was evaluated using immunostaining. In addition, eNOS expression and levels of cellular senescence markers were measured in RNA and proteins extracted from whole aortic tissue. KD-like vasculitis impaired vascular endothelial cells that produce eNOS, which maintains vascular homeostasis, and promoted macrophage infiltration into the tissue. Statins also restored vascular endothelial cell function by promoting eNOS expression. Statins may be used to prevent secondary cardiovascular events during the chronic phase of KD.

Long-term cardiovascular complications following sepsis: is senescence the missing link?

Among the long-term consequences of sepsis (also termed “post-sepsis syndrome”) the increased risk of unexplained cardiovascular complications, such as myocardial infarction, acute heart failure or stroke, is one of the emerging specific health concerns. The vascular accelerated ageing also named premature senescence is a potential mechanism contributing to atherothrombosis, consequently leading to cardiovascular events. Indeed, vascular senescence-associated major adverse cardiovascular events (MACE) are a potential feature in sepsis survivors and of the elderly at cardiovascular risk. In these patients, accelerated vascular senescence could be one of the potential facilitating mechanisms. This review will focus on premature senescence in sepsis regardless of age. It will highlight and refine the potential relationships between sepsis and accelerated vascular senescence. In particular, key cellular mechanisms contributing to cardiovascular events in post-sepsis syndrome will be highlighted, and potential therapeutic strategies to reduce the cardiovascular risk will be further discussed.

With improved management of patients, sepsis survivors are increasing each year.

Early cardiovascular complications, of yet undeciphered mechanisms, are an emerging health issue in post-sepsis syndrome.

Premature senescence of endothelium and vascular tissue is proven an accelerated process of atherogenesis in young septic rats.

An increasing body of clinical evidence point at endothelial senescence in the initiation and development of atherosclerosis.

Prevention of premature senescence by senotherapy and cardiological follow-up could improve long-term septic patients’ outcomes.