Age-dependent vulnerability to experimental acute pancreatitis is associated with increased systemic inflammation and thrombosis

Characteristic of pancreatic involvement in melioidosis: Case report and literature review

Background

Intra-abdominal abscesses are a frequent manifestations of melioidosis whereas pancreas is barely affected by this condition. Herein, by delving into the clinical manifestations, diagnostic processes, and the ultimate clinical outcome, we report a case of an unusual presentation of pancreatic melioidosis in a Chinese patient, aiming to shed light on a diagnosis that is not commonly associated with the pancreas.

Case presentation

The patient, a 32-year-old male farmer, suffered from persistent burning pain in his upper abdomen, accompanied by nausea, vomiting, fever and other symptoms, presented to the clinic. His body temperature spiked to 38.5 °C without apparent reason for this fever. A thorough examination, including the blood culture and the imaging examination, led to a diagnosis of pancreatic melioidosis. The patient was promptly treated with intravenous meropenem and ceftazidime. As a consequence, his symptoms eased and discharged in stable condition. The patient continued his treatment with oral trimethoprim-sulfamethoxazole (co-trimoxazole) for three months to control the infection. Following 6 months of regular follow-up, the patient fully recovered.

Conclusions

In tropical regions such as Hainan, it is crucial to consider atypical infection like B. pseudomallei in the differential diagnosis, even when they present in atypical locations such as a pancreatic pseudocyst. Detecting pancreatic involvement in melioidosis relies heavily on sensitive bacterial culture and imaging examination. This retrospective study of patients' infection diagnosis aims to shed light on the clinical treatment, and prognosis associated with pancreatic melioidosis, thereby raising awareness about the risk of pancreatic affection in melioidosis cases.

Administration of Warfarin Inhibits the Development of Cerulein-Induced Edematous Acute Pancreatitis in Rats

Acute pancreatitis (AP) is a severe disease with high morbidity and mortality in which inflammation and coagulation play crucial roles. The development of inflammation leads to vascular injury, endothelium and leukocytes stimulation, and an increased level of tissue factor, which results in the activation of the coagulation process. For this reason, anticoagulants may be considered as a therapeutic option in AP. Previous studies have shown that pretreatment with heparin, low-molecular-weight heparin (LMWH), or acenocoumarol inhibits the development of AP. The aim of the present study was to check if pretreatment with warfarin affects the development of edematous pancreatitis evoked by cerulein. Warfarin (90, 180, or 270 µg/kg/dose) or saline were administered intragastrically once a day for 7 days consecutively before the induction of AP. AP was evoked by the intraperitoneal administration of cerulein. The pre-administration of warfarin at doses of 90 or 180 µg/kg/dose reduced the histological signs of pancreatic damage in animals with the induction of AP. Additionally, other parameters of AP, such as an increase in the serum activity of lipase and amylase, the plasma concentration of D-dimer, and interleukin-1β, were decreased. In addition, pretreatment with warfarin administered at doses of 90 or 180 µg/kg/dose reversed the limitation of pancreatic blood flow evoked by AP development. Warfarin administered at a dose of 270 µg/kg/dose did not exhibit a preventive effect in cerulein-induced AP. Conclusion: Pretreatment with low doses of warfarin inhibits the development of AP evoked by the intraperitoneal administration of cerulein.

65 yaş üstü hastalarda puanlama sistemlerinin şiddetli akut pankreatiti ve mortaliteyi erken öngörme açısından değerlendirilmesi

Purpose: The aim of this study is to investigate the power of disease severity scores to predict the development of Severe Acute Pancreatitis (SAP) and mortality in the early period over 65 years old diagnosed with acute pancreatitis in the emergency department. Materials and Methods: We calculated RANSON (on admission) and Computed Tomography Severity Index (CTSI) in addition to Bedside Index for Severity in Acute Pancreatitis (BISAP) score on admission to the emergency department. Results: One hundred and sixty patients (46.9% over 80 years of age) were included in the study. We observed statistically higher length of hospitalization, longer duration of stay in the intensive care unit, SAP and higher mortality in patients over 80 years of age. When we examined the ROC curve, we determined that the AUC values of the BISAP score were highest in both SAP and mortality estimation (AUC: 0.911, 95% CI 0.861-0.962; AUC: 0.918, 95% CI 0.864-0.9722, respectively). Binary logistic analysis indicated a 4.7-fold increased risk for SAP and a 12.3-fold increased mortality for each unit increase in BISAP score value. Conclusion: BISAP may be a good predictor for SAP and mortality estimation on admission to the emergency department in patients over 65 years of age with acute pancreatitis.

Visceral fat-specific regulation of plasminogen activator inhibitor-1 in aged septic mice

Elevated plasma levels of plasminogen activator inhibitor-1 (PAI-1) are documented in patients with sepsis and levels positively correlate with disease severity and mortality. Our previous work demonstrated that visceral adipose tissues (VAT) are a major source of PAI-1, especially in the aged (murine endotoxemia), that circulating PAI-1 protein levels match the trajectory of PAI-1 transcript levels in VAT (clinical sepsis), and that PAI-1 in both VAT and plasma are positively associated with acute kidney injury (AKI) in septic patients. In the current study utilizing preclinical sepsis models, PAI-1 tissue distribution was examined and cellular sources, as well as mechanisms mediating PAI-1 induction in VAT, were identified. In aged mice with sepsis, PAI-1 gene expression was significantly higher in VAT than in other major organs. VAT PAI-1 gene expression correlated with PAI-1 protein levels in both VAT and plasma. Moreover, VAT and plasma levels of PAI-1 were positively associated with AKI markers, modeling our previous clinical data. Using explant cultures of VAT, we determined that PAI-1 is secreted robustly in response to recombinant transforming growth factor β (TGFβ) and tumor necrosis factor α (TNFα) treatment; however, neutralization was effective only for TNFα indicating that TGFβ is not an endogenous modulator of PAI-1. Within VAT, TNFα was localized to neutrophils and macrophages. PAI-1 protein levels were fourfold higher in stromal vascular fraction (SVF) cells compared with mature adipocytes, and among SVF cells, both immune and nonimmune compartments expressed PAI-1 in a similar fashion. PAI-1 was localized predominantly to macrophages within the immune compartment and preadipocytes and endothelial cells within the nonimmune compartment. Collectively, these results indicate that induction and secretion of PAI-1 from VAT is facilitated by a complex interaction among immune and nonimmune cells. As circulating PAI-1 contributes to AKI in sepsis, understanding PAI-1 regulation in VAT could yield novel strategies for reducing systemic consequences of PAI-1 overproduction.

Divergent Sepsis Pathophysiology in Older Adults

Significance: Both incidence and mortality rates of sepsis significantly increase with advanced age, and the majority of sepsis patients are late middle-aged or older. With the proportion of older adults rapidly increasing in developed countries, age-dependent sepsis vulnerability is an urgent medical issue. Due to an increasing life expectancy, postsepsis complications and health care costs are expected to increase as well. Recent Advances: Older patients suffer from higher sepsis incidence and mortality rates, likely resulting from frequent comorbidities, increased coagulation, dysgylcemia, and altered immune responses. Critical Issues: Despite a large number of ongoing clinical and basic research studies, there is currently no effective therapeutic strategy targeting older patients with severe sepsis. The disparity between clinical and basic studies is a problem, and this is largely due to the use of animal models lacking clinical relevance. Although the majority of sepsis cases occur in older adults, most laboratory animals used for sepsis research are very young. Further, despite the wide use of combination fluid and antibiotic treatment in intensive care unit (ICU) patients, most animal research does not include such treatment. Future Directions: Because sepsis is a systemic disease with multiple organ dysfunction, combined therapy approaches, not those targeting single pathways or single organs, are essential. As for preclinical research, it is critical to confirm new findings using aged animal models with clinically relevant ICU-like medical treatments. Antioxid. Redox Signal. 35, 1358-1375.

Local and systemic effects of aging on acute pancreatitis

BACKGROUND

/Objectives: Evaluation of the local and systemic effects of aging on the severity of acute pancreatitis (AP) in an experimental rat model in elderly animals.

METHODS

AP was induced in Wistar rats by intraductal 2.5% taurocholate injection and divided into two groups: Young (3 month old) and Aged (18 month old). Two and 24 h after AP induction blood samples were collected for determinations of amylase, AST, ALT, urea, creatinine, glucose, and of plasma I-FABP. TNF-α and IL-6 levels were determined in serum and ascitic fluid. Liver mitochondrial function and malondialdehyde (MDA) contents, pancreas histological analysis, and pulmonar myeloperoxidade (MPO) activity were performed. Bacterial translocation was evaluated by bacterial cultures of pancreas.

RESULTS

A significant increase in serum amylase, AST, ALT, urea, creatinine, glucose, I-FABP, and IL-6 levels, and a reduction in serum and ascitic fluid TNF-α levels were observed in the aged group compared to the young group. Liver mitochondrial dysfunction, MDA contents, and pulmonary MPO activity were increased in the Aged AP group compared to the Young AP group. Positive bacterial cultures obtained from pancreas tissue in aged group were significantly increased compared to the young group. Acinar necrosis was also increased in aged AP group when compared to young AP group.

CONCLUSION

Aging worsens the course of acute pancreatitis evidenced by increased local and systemic lesions and increased bacterial translocation.

Molecular and Clinical Issues about the Risk of Venous Thromboembolism in Older Patients: A Focus on Parkinson's Disease and Parkinsonism

Venous thromboembolism (VTE) is a common and potentially life-threatening condition which includes both deep-vein thrombosis (DVT) and pulmonary embolism (PE). VTE has a significant clinical and epidemiological impact in the elderly, and its incidence increases to more than 1% per year in older patients, suggesting the presence of specific age-related risk factors in this population. Immobilization seems to predominate as the main cause in patients admitted for medical acute illness in medicine wards, and there is evidence of a high risk in older patients with immobilization resulting from advanced forms of Parkinson’s disease (PD), regardless of the presence of an acute medical condition. In this review, we would to discuss the recent evidence on clinical, molecular and epidemiological features of VTE in older frail subjects focusing on patients with PD and parkinsonism. We also discuss some therapeutic issues about the risk prevention and we suggest a thorough comprehensive geriatric assessment that can represent an optimal strategy to identify and prevent the VTE risk in these patients.

Late Therapeutic Intervention with Antibiotics and Fluid Resuscitation Allows for a Prolonged Disease Course with High Survival in a Severe Murine Model of Sepsis

Current animal models of sepsis often incorporate antibiotics to be consistent with clinical standards for treatment of patients in the intensive care unit. However, such experimental intervention is commonly initiated very early after infectious insult, which likely blunts the progression of systemic inflammation and downstream pathology. The objective of this study was to establish an animal model of sepsis with delayed therapeutic intervention, allowing a longer disease course and downstream pathology, but still resulting in a high survival rate. Severe lethal abdominal infection was initiated in young adult (17-18-week-old) C57BL/6 mice by cecal slurry (CS) injection. When initiated early (1- or 6-h post-CS injection), antibiotic treatment (imipenem, 1.5 mg/mouse i.p., twice/day for 5 days) rescued the majority of mice; however, few of these mice showed evidence of bacteremia, cytokinemia, or organ injury. When antibiotic treatment was delayed until late time-points (12- or 24-h post-CS injection) the majority of animals did not survive beyond 48 h. When fluid resuscitation (physiological saline, s.c.) was performed in combination with antibiotic treatment (twice daily) beginning at these late time-points, the majority of mice survived (75%) and showed bacteremia, cytokinemia, organ dysfunction, and prolonged body weight loss (<90% for 4 weeks). We recommend that this new repeated combination treatment with antibiotics and fluids resuscitation be initiated at a late time point after bacteremia becomes evident because this model more closely mimics the downstream pathological characteristics of severe clinical sepsis yet maintains a high survival rate. This model would be advantageous for studies on severe sepsis and postintensive care illness.

Acute kidney injury and inflammatory response of sepsis following cecal ligation and puncture in d-galactose-induced aging rats

Background

Recently, the d-galactose (d-gal)-induced mimetic aging rat model has been widely used in studies of age-associated diseases, which have shown that chronic d-gal exposure induces premature aging similar to natural aging in rats. With the increasing rate of sepsis in the geriatric population, an easy-access animal model for preclinical studies of elderly sepsis is urgently needed. This study investigates whether a sepsis model that is established in d-gal-induced aging rats can serve as a suitable model for preclinical studies of elderly patients with sepsis.

Objective

To investigate the acute kidney injury (AKI) and inflammatory response of sepsis following cecal ligation and puncture (CLP) in d-gal-induced aging rats.

Methods

Twelve-week-old male Sprague Dawley rats were divided into low-dose d-gal (L d-gal, 125 mg/kg/d), high-dose d-gal (H d-gal, 500 mg/kg/d), and control groups. After daily subcutaneous injection of d-gal for 6 weeks, the CLP method was used to establish a sepsis model.

Results

The mortality was 73.3%, 40%, and 33.3% in the H d-gal, L d-gal, and control groups, respectively. Blood urea nitrogen, creatinine, plasma neutrophil gelatinase-associated lipocalin, interleukin-6, interleukin-10, and tumor necrosis factor-α were markedly increased in the H d-gal group after establishment of the sepsis model (H d-gal vs control, P<0.05 at 12 h and 24 h post-CLP). The rate of severe AKI (RIFLE-F) at 24 h post-CLP was 43% for both the control and L d-gal groups and 80% for the H d-gal group.

Conclusion

High-dose- d-gal-induced aging rats are more likely to die from sepsis than are young rats, and probably this is associated with increased severity of septic AKI and an increased inflammatory response. Therefore, use of the high-dose- d-gal-induced aging rat model of sepsis for preclinical studies can provide more useful information for the treatment of sepsis in elderly patients.

Acetaminophen hepatotoxicity in mice: Effect of age, frailty and exposure type

Acetaminophen is a commonly used analgesic that can cause severe hepatotoxicity in overdose. Despite old age and frailty being associated with extensive and long-term utilization of acetaminophen and a high prevalence of adverse drug reactions, there is limited information on the risks of toxicity from acetaminophen in old age and frailty. This study aimed to assess changes in the risk and mechanisms of hepatotoxicity from acute, chronic and sub-acute acetaminophen exposure with old age and frailty in mice. Young and old male C57BL/6 mice were exposed to either acute (300 mg/kg via oral gavage), chronic (100 mg/kg/day in diet for six weeks) or sub-acute (250 mg/kg, t.i.d., for three days) acetaminophen, or saline control. Pre-dosing mice were scored for the mouse clinical frailty index, and after dosing serum and liver tissue were collected for assessment of toxicity and mechanisms. There were no differences with old age or frailty in the degree of hepatotoxicity induced by acute, chronic or subacute acetaminophen exposure as assessed by serum liver enzymes and histology. Age-related changes in the acetaminophen toxicity pathways included increased liver GSH concentrations, increased NQO1 activity and an increased pro- and anti-inflammatory response to acetaminophen in old age. Frailty-related changes included a negative correlation between frailty index and serum protein, albumin and ALP concentrations for some mouse groups. In conclusion, although there were changes in some pathways that would be expected to influence susceptibility to acetaminophen toxicity, there was no overall increase in acetaminophen hepatotoxicity with old age or frailty in mice.

Intestinal barrier dysfunction and increased COX-2 gene expression in the gut of elderly rats with acute pancreatitis

BACKGROUND/OBJECTIVES

The clinical course of acute pancreatitis can vary from mild to severe. In its most severe manifestation, acute pancreatitis is associated with an exacerbated systemic inflammatory response and high mortality rates. The severe form of acute pancreatitis is more frequent in elderly patients than in young patients, but the mechanisms underlying this difference are still under investigation.

METHODS

Rats were divided into two groups as follows: Group 1, young rats; and Group 2, old rats. Acute pancreatitis group was induced by a retrograde injection of a sodium taurocholate solution into the biliopancreatic duct. Using this model of acute pancreatic injury, we designed a study to investigate possible differences in microbial translocation and characteristics of the intestinal barrier between elderly and young rats.

RESULTS

There was a significantly higher number of bacterial colonies in the pancreas of elderly rats compared with young rats following pancreas injury, which was associated with a more severe local intestinal inflammatory response that included elevated gene expression of COX-2 and a decreased gene expression of tight junction proteins.

CONCLUSIONS

We conclude that intestinal damage during acute pancreatitis is exacerbated in elderly rats compared with young rats and that COX-2 inhibition could be a potential therapeutic target to offer tailored treatment for acute pancreatitis in the elderly.

High-mobility group box 1 protein and its role in severe acute pancreatitis

The high mobility group box 1 (HMGB1), which belongs to the subfamily of HMG-1/-2, is a highly conserved single peptide chain consisting of 215 amino acid residues with a molecular weight of approximately 24894 Da. HMGB1 is a ubiquitous nuclear protein in mammals and plays a vital role in inflammatory diseases. Acute pancreatitis is one of the most common causes of acute abdominal pain with a poor prognosis. Acute pancreatitis is an acute inflammatory process of the pancreas (duration of less than six months), for which the severe form is called severe acute pancreatitis (SAP). More and more studies have shown that HMGB1 has a bidirectional effect in the pathogenesis of SAP. Extracellular HMGB1 can aggravate the pancreatic inflammatory process, whereas intracellular HMGB1 has a protective effect against pancreatitis. The mechanism of HMGB1 is multiple, mainly through the nuclear factor-κB pathway. Receptors for advanced glycation end-products and toll-like receptors (TLR), especially TLR-2 and TLR-4, are two major types of receptors mediating the inflammatory process triggered by HMGB1 and may be also the main mediators in the pathogenesis of SAP. HMGB1 inhibitors, such as ethyl pyruvate, pyrrolidine dithiocarbamate and Scolopendra subspinipes mutilans, can decrease the level of extracellular HMGB1 and are the promising targets in the treatment of SAP.

Integrated traditional Chinese medicine improves acute pancreatitis via the downregulation of PRSS1 and SPINK1

Integrated traditional Chinese medicine (ITCM) is known to improve health in patients with acute pancreatitis (AP); however, the molecular mechanisms underlying this effect are unknown. AP is associated with the expression of PRSS1 and SPINK1. Thus, the present study aimed to investigate whether ITCM was able to ameliorate AP by regulating the expression levels of protein, serine 1 (PRSS1) and serine peptidase inhibitor, Kazal type 1 (SPINK1). A total of 100 AP patients were divided at random into two groups. The treatment group were treated externally with a herbal ITCM preparation, while the control group received a routine placebo treatment. The mRNA and protein expression levels of PRSS1 and SPINK1 were subsequently compared between the two groups. The results revealed that the health of the patients who had received ITCM improved significantly when compared with the control group patients (P<0.05). In addition, the expression levels of PRSS1 and SPINK1 were found to be lower in the treatment group when compared with the control group (P<0.05). Therefore, ITCM exhibited a significant therapeutic effect on AP and produced no side effects since the treatment was applied externally. ITCM may ameliorate AP by downregulating the expression of PRSS1 and SPINK1; thus, should be considered as a potential therapy for the development of drugs against AP.

A new cecal slurry preparation protocol with improved long-term reproducibility for animal models of sepsis

Sepsis, a life-threatening systemic inflammatory response syndrome induced by infection, is widely studied using laboratory animal models. While cecal-ligation and puncture (CLP) is considered the gold standard model for sepsis research, it may not be preferable for experiments comparing animals of different size or under different dietary regimens. By comparing cecum size, shape, and cecal content characteristics in mice under different experimental conditions (aging, diabetes, pancreatitis), we show that cecum variability could be problematic for some CLP experiments. The cecal slurry (CS) injection model, in which the cecal contents of a laboratory animal are injected intraperitoneally to other animals, is an alternative method for inducing polymicrobial sepsis; however, the CS must be freshly prepared under conventional protocols, which is a major disadvantage with respect to reproducibility and convenience. The objective of this study was to develop an improved CS preparation protocol that allows for long-term storage of CS with reproducible results. Using our new CS preparation protocol we found that bacterial viability is maintained for at least 6 months when the CS is prepared in 15% glycerol-PBS and stored at -80°C. To test sepsis-inducing efficacy of stored CS stocks, various amounts of CS were injected to young (4-6 months old), middle-aged (12-14 months old), and aged (24-26 months old) male C57BL/6 mice. Dose- and age-dependent mortality was observed with high reproducibility. Circulating bacteria levels strongly correlated with mortality suggesting an infection-mediated death. Further, injection with heat-inactivated CS resulted in acute hypothermia without mortality, indicating that CS-mediated death is not due to endotoxic shock. This new CS preparation protocol results in CS stocks which are durable for freezing preservation without loss of bacterial viability, allowing experiments to be performed more conveniently and with higher reproducibility than before.

Increased coagulation and suppressed generation of activated protein C in aged mice during intra-abdominal sepsis

Sepsis is a life-threatening clinical condition that is particularly serious among the elderly who experience considerably higher mortality rates compared with younger patients. Using a sterile endotoxemia model, we previously reported age-dependent mortality in conjunction with enhanced coagulation and insufficient levels of anti-coagulant factor activated protein C (aPC). The purpose of the present study was to further investigate the mechanisms for age-dependent coagulation and aPC insufficiency during experimental sepsis. Intra-abdominal sepsis was induced by cecal ligation and puncture (CLP) using 21 or 16 gauge (G) needles (double-puncture) on young (4 to 6 mo old) and aged (20 to 25 mo old) male C57BL/6 mice. When compared with young mice, aged mice showed significantly increased mortality (92% vs. 28%), systemic inflammation, and coagulation in the lung and kidney after 21G CLP. Young mice with more severe CLP (16G) showed a mortality rate and inflammation equivalent to aged mice with 21G CLP; however, enhanced coagulation and kidney dysfunction were significant only in the aged. In young mice, increased levels of aPC after CLP were coupled with reduced levels of protein C (PC), suggesting the conversion of PC to aPC; however, PC and aPC levels remained unchanged in aged mice, indicating a lack of PC to aPC conversion. Activation of fibrinolysis, determined by plasma d-dimer levels, was similar regardless of age or CLP severity, and plasminogen activator inhibitor-1, an inhibitor of fibrinolysis, showed severity-dependent induction independent of age. These results suggest that enhanced coagulation in aged mice during sepsis is due to dysfunction of the PC activation mechanism.

Age-Associated Increase in Cytokine Production During Systemic Inflammation-II: The Role of IL-1β in Age-Dependent IL-6 Upregulation in Adipose Tissue

Expression of interleukin-6 (IL-6) upon acute inflammatory stress is significantly augmented by aging in adipose tissue, a major source of this cytokine. In the present study, we examined the mechanism of age-dependent IL-6 overproduction using visceral white adipose tissue from C57BL/6 mice. Upon treatment with lipopolysaccharide (LPS) in vitro, IL-6 was produced by adipose tissue explants, and secreted levels were significantly higher in cultures from aged (24 months) mice compared to young (4 months). Interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNFα), two inducers of IL-6, were mainly produced by the lungs and spleen rather than adipose tissue in mice after LPS injection. Treatment of adipose explants with physiological levels of IL-1β induced significant age-dependent secretion of IL-6, while treatment with TNFα had little effect, demonstrating an augmented response of adipose tissues to IL-1β in the aged. In vitro experiments utilizing a neutralizing antibody against IL-1β and in vivo experiments utilizing IL-1-receptor-1 deficient mice, confirmed that IL-6 overproduction in the aged is regulated by autocrine/paracrine action of IL-1β which specifically occurs in aged adipose tissues. These findings indicate an elevated inflammatory potential of adipose tissue in the aged and a unique IL-1β-mediated mechanism for IL-6 overproduction, which may impact age-associated vulnerability to acute inflammatory diseases such as sepsis.

The mtDNA nt7778 G/T polymorphism augments formation of lymphocytic foci but does not aggravate cerulein-induced acute pancreatitis in mice

A polymorphism in the ATP synthase 8 (ATP8) gene of the murine mitochondrial genome, G-to-T transversion at position 7778, has been suggested to increase susceptibility to multiple autoimmune diseases, including autoimmune pancreatitis (AIP). The polymorphism also induces mitochondrial reactive oxygen species generation, secretory dysfunction and β-cell mass adaptation. Here, we have used two conplastic mouse strains, C57BL/6N-mtAKR/J (B6-mtAKR; nt7778 G; control) and C57BL/6N-mtFVB/N (B6-mtFVB; nt7778 T), to address the question if the polymorphism also affects the course of cerulein-induced acute pancreatitis in mice. Therefore, two age groups of mice (3 and 12-month-old, respectively) were subjected to up to 7 injections of the secretagogue cerulein (50 µg/kg body weight) at hourly intervals. Disease severity was assessed at time points from 3 hours to 7 days based on pancreatic histopathology, serum levels of α-amylase and activities of myeloperoxidase (MPO) in lung tissue. A comparison of cerulein-induced pancreatic tissue damage and increases of α-amylase and MPO activities showed no differences between the age-matched groups of both strains. Interestingly, histological evaluation of pancreatic tissue of both untreated and cerulein-treated B6-mtAKR and B6-mtFVB mice also revealed the presence of infiltrates of immune cells surrounding ducts and vessels; a finding that is compatible with an early stage of AIP. After recovery from cerulein-induced pancreatitis (day 7 after the injections), 12-month-old B6-mtFVB mice but not B6-mtAKR mice displayed aggravated lymphocytic lesions. A comparison of 12-month-old mice with other age groups of both strains revealed that lymphocytic foci were largely absent in 3-month-old mice, while 24-month-old mice were more affected. Together, our data suggest that the mtDNA nt7778 G/T polymorphism does not aggravate cerulein-induced acute pancreatitis. Autoimmune-like lesions, however, may progress faster if additional tissue damage occurs.

Histological Evidence of Increased Osteoclast Cell Number and Asymmetric Bone Resorption Activity in the Tibiae of Interleukin-6-Deficient Mice

Interleukin-6 (IL-6) is a multifunctional cytokine considered to modulate bone homeostasis. Based on previous contradictory studies, we aimed to verify the influence of IL-6 deficiency on bone remodeling using an IL-6 knockout (IL-6-/-) murine model. Eight-month-old male mice, homozygous for the disrupted IL-6 gene, and their wild type (WT) littermates (control), were used. After transcardiac perfusion, tibiae were removed for histochemical analysis. Compared with the control group, IL-6 deficiency increased tartrate resistant acid phosphatase (TRAP)-positive osteoclast numbers and up-regulated the alkaline phosphatase (ALP) activity of osteoblasts in the metaphysis of the tibia. However, further analysis of serial histological sections from IL-6-/- mice found a significant discrepancy in osteoclast number, with the higher number of TRAP-positive osteoclasts conflicting with the lower number of cathepsin K-positive osteoclasts. Moreover, TUNEL staining identified a significantly higher rate of osteoclast apoptosis in IL-6-/- mice as compared with their WT controls. IL-6 deficiency induced abundant TRAP-positive osteoclasts but delayed bone remodeling by significantly inhibiting the bone resorption activity of osteoclasts and promoting osteoclast apoptosis.

Sepsis in old age: review of human and animal studies

Sepsis is a serious problem among the geriatric population as its incidence and mortality rates dramatically increase with advanced age. Despite a large number of ongoing clinical and basic research studies, there is currently no effective therapeutic strategy that rescues elderly patients with severe sepsis. Recognition of this problem is relatively low as compared to other age-associated diseases. The disparity between clinical and basic studies is a problem, and this is likely due, in part, to the fact that most laboratory animals used for sepsis research are not old while the majority of sepsis cases occur in the geriatric population. The objective of this article is to review recent epidemiological studies and clinical observations, and compare these with findings from basic laboratory studies which have used aged animals in experimental sepsis.

The clinical course of acute pancreatitis and the inflammatory mediators that drive it

Acute pancreatitis (AP) is a common emergency condition. In the majority of cases, it presents in a mild and self-limited form. However, about 20% of patients develop severe disease with local pancreatic complications (including necrosis, abscess, or pseudocysts), systemic organ dysfunction, or both. A modern classification of AP severity has recently been proposed based on the factors that are causally associated with severity of AP. These factors are both local (peripancreatic necrosis) and systemic (organ failure). In AP, inflammation is initiated by intracellular activation of pancreatic proenzymes and/or nuclear factor-κB. Activated leukocytes infiltrate into and around the pancreas and play a central role in determining AP severity. Inflammatory reaction is first local, but may amplify leading to systemic overwhelming production of inflammatory mediators and early organ failure. Concomitantly, anti-inflammatory cytokines and specific cytokine inhibitors are produced. This anti-inflammatory reaction may overcompensate and inhibit the immune response, rendering the host at risk for systemic infection. Currently, there is no specific treatment for AP. However, there are several early supportive treatments and interventions which are beneficial. Also, increasing the understanding of the pathogenesis of systemic inflammation and the development of organ dysfunction may provide us with future treatment modalities.