Effects of rare kidney diseases on kidney failure: a longitudinal analysis of the UK National Registry of Rare Kidney Diseases (RaDaR) cohort

BACKGROUND

Individuals with rare kidney diseases account for 5-10% of people with chronic kidney disease, but constitute more than 25% of patients receiving kidney replacement therapy. The National Registry of Rare Kidney Diseases (RaDaR) gathers longitudinal data from patients with these conditions, which we used to study disease progression and outcomes of death and kidney failure.

METHODS

People aged 0-96 years living with 28 types of rare kidney diseases were recruited from 108 UK renal care facilities. The primary outcomes were cumulative incidence of mortality and kidney failure in individuals with rare kidney diseases, which were calculated and compared with that of unselected patients with chronic kidney disease. Cumulative incidence and Kaplan-Meier survival estimates were calculated for the following outcomes: median age at kidney failure; median age at death; time from start of dialysis to death; and time from diagnosis to estimated glomerular filtration rate (eGFR) thresholds, allowing calculation of time from last eGFR of 75 mL/min per 1·73 m2 or more to first eGFR of less than 30 mL/min per 1·73 m2 (the therapeutic trial window).

FINDINGS

Between Jan 18, 2010, and July 25, 2022, 27 285 participants were recruited to RaDaR. Median follow-up time from diagnosis was 9·6 years (IQR 5·9-16·7). RaDaR participants had significantly higher 5-year cumulative incidence of kidney failure than 2·81 million UK patients with all-cause chronic kidney disease (28% vs 1%; p<0·0001), but better survival rates (standardised mortality ratio 0·42 [95% CI 0·32-0·52]; p<0·0001). Median age at kidney failure, median age at death, time from start of dialysis to death, time from diagnosis to eGFR thresholds, and therapeutic trial window all varied substantially between rare diseases.

INTERPRETATION

Patients with rare kidney diseases differ from the general population of individuals with chronic kidney disease: they have higher 5-year rates of kidney failure but higher survival than other patients with chronic kidney disease stages 3-5, and so are over-represented in the cohort of patients requiring kidney replacement therapy. Addressing unmet therapeutic need for patients with rare kidney diseases could have a large beneficial effect on long-term kidney replacement therapy demand.

FUNDING

RaDaR is funded by the Medical Research Council, Kidney Research UK, Kidney Care UK, and the Polycystic Kidney Disease Charity.

Why is diagnosis, investigation and improved management of kidney stone disease important? Non-pharmacological and pharmacological treatments for nephrolithiasis

INTRODUCTION

Progress in the medical treatment and management of nephrolithiasis has been limited to date and continues to depend on urinary metabolic screening to assess excretion of the main stone constituents, factors determining stone solubility and precipitation, and on dietary and lifestyle recommendations.

AREAS COVERED

In this review, we try to highlight some of the broader aspects of kidney stone disease in relation to recent epidemiological and pathophysiological findings, and emerging new treatments. Specifically, this review will cover recent evidence on the association between metabolic risk factors and kidney stone disease, dietary risk factors and dietary interventions to prevent kidney stones, and how genomics, metabolomics and proteomics may improve diagnosis and treatment of this troublesome, if rarely fatal, condition. PubMed was used to identify the most suitable references according to our search strategy; only full manuscripts were included.

EXPERT OPINION

What is emerging is that kidney stone disease is not an isolated disorder, but is systemic in nature with links to important and common co-morbidities such as diabetes, hypertension, cardiovascular disease, and chronic kidney disease. These associations support the need to take nephrolithiasis seriously as a medical condition and to adopt a more holistic approach to its investigation and treatment.

Early renal failure in childhood in a male with Fabry disease

Fabry disease is an X-linked lysosomal storage disorder caused by reduced activity or absence of the alpha-galactosidase A enzyme resulting in systemic accumulation of glycosphingolipids. End-stage renal disease (ESRD) is a late-stage manifestation of Fabry disease, typically presenting in the fifth decade of life, but is very rare in childhood. Here we present a case of an 11-year-old boy with classical Fabry disease presenting with ESRD requiring haemodialysis and transplant. Diagnosis was confirmed by renal biopsy, GLA mutation and low alpha-galactosidase A levels. He has an unusual genotype, hemizygous for the c.1000–11T>A intronic variant and positive for the pseudodeficiency allele D313Y. Due to the possibility of very early and accelerated disease progression, Fabry disease should be considered as a possible diagnosis in unexplained renal failure in males from a younger age.

Circulating Antibodies to Skin Bacteria Detected by Serological Lateral Flow Immunoassays Differentially Correlated With Bacterial Abundance

The serological lateral flow immunoassay (LFIA) was used to detect circulating antibodies to skin bacteria. Next-generation sequencing analysis of the skin microbiome revealed a high relative abundance of Cutibacterium acnes but low abundance of Staphylococcus aureus and Corynebacterium aurimucosum on human facial samples. Yet, results from both LFIA and antibody titer quantification in 96-well microplates illustrated antibody titers that were not correspondent, and instead negatively correlated, to their respective abundance with human blood containing higher concentrations of antibodies to both S. aureus and C. aurimucosum than C. acnes. Acne vulgaris develops several unique microbial and cellular features, but its correlation with circulating antibodies to bacteria in the pilosebaceous unit remains unknown. Results here revealed that antibodies to C. acnes and S. aureus were approximately 3-fold higher and 1.5-fold lower, respectively, in acne patients than in healthy subjects. Although the results can be further validated by larger sample sizes, the proof-of-concept study demonstrates a newfound discrepancy between the abundance of skin bacteria and amounts of their corresponding antibodies. And in light of acne-correlated amplified titers of specific anticommensal antibodies, we highlight that profiling these antibodies in the pilosebaceous unit by LFIAs may provide a unique signature for monitoring acne vulgaris.

Urinary metabolic profile and stone composition in kidney stone formers with and without heart disease

Objective

Kidney stone disease seems to be associated with an increased risk of incident cardiovascular outcomes; the aim of this study is to identify differences in 24-h urine excretory profiles and stone composition among stone formers with and without cardiovascular disease (CVD).

Methods

Data from patients attending the Department of Renal Medicine’s metabolic stone clinic from 1995 to 2012 were reviewed. The sample was divided according to the presence or absence of CVD (myocardial infarction, angina, coronary revascularization, or surgery for calcified heart valves). Univariable and multivariable regression models, adjusted for age, sex, BMI, hypertension, diabetes, eGFR, plasma bicarbonate and potential renal acid load of foods were used to investigate differences across groups.

Results

1826 patients had available data for 24-h urine analysis. Among these, 108 (5.9%) had a history of CVD. Those with CVD were older, have higher prevalence of hypertension and diabetes and lower eGFR. Univariable analysis showed that patients with CVD had significantly lower 24-h urinary excretions for citrate (2.4 vs 2.6 mmol/24 h, p = 0.04), magnesium (3.9 vs 4.2 mmol/24 h, p = 0.03) and urinary pH (6.1 vs 6.2, p = 0.02). After adjustment for confounders, differences in urinary citrate and magnesium excretions remained significant. No differences in the probability of stone formation or stone compositions were found.

Conclusions

Stone formers with CVD have lower renal alkali excretion, possibly suggesting higher acid retention in stone formers with cardiovascular comorbidities. Randomized clinical trials including medications and a controlled diet design are needed to confirm the results presented here.

Graphic abstract

LB002ILLUMINATE-A, A PHASE 3 STUDY OF LUMASIRAN, AN INVESTIGATIONAL RNAI THERAPEUTIC, IN CHILDREN AND ADULTS WITH PRIMARY HYPEROXALURIA TYPE 1 (PH1)

Background and Aims

PH1 is a rare genetic disorder characterized by hepatic oxalate overproduction, leading to recurrent kidney stones, nephrocalcinosis, progressive kidney failure, and multiorgan damage from systemic oxalosis. There are no approved pharmacologic therapies for PH1. Lumasiran is a subcutaneously-administered investigational RNAi therapeutic that targets glycolate oxidase to reduce hepatic oxalate production. We report the first results from the six-month, double-blind period of ILLUMINATE-A, a randomized, placebo-controlled Phase 3 study to evaluate lumasiran in patients with PH1.

Method

Key inclusion criteria: age≥6 years, 24hr urinary oxalate (UOx)≥0.70 mmol/24hr/1.73m2, confirmed PH1 diagnosis, eGFR≥30 mL/min/1.73m2. Randomization: 2:1; lumasiran (n=26), placebo (n=13). Dosing: 3 mg/kg monthly×3, then quarterly. Primary endpoint: percent change in 24hr UOx excretion from baseline to month (M) 6. Primary comparison: least square (LS) mean treatment difference in percent change from baseline (average of M3-6).

Results

Lumasiran led to a statistically significant percent reduction in 24hr UOx excretion compared to placebo: the LS mean change from baseline to M6 (average of M3-6) was −65.4% with lumasiran and −11.8% with placebo (LS mean difference: −53.5%; p=1.7 × 10−14). Subgroup analyses of the primary endpoint showed a consistent effect of lumasiran across age, baseline UOx, eGFR, and concomitant pyridoxine use. Lumasiran led to statistically significant improvements in all hierarchically tested secondary endpoints, including: proportion of lumasiran-treated patients that achieved normalization or near-normalization of 24hr UOx at M6 (84% vs 0% of placebo-treated patients, p=8.3 × 10−7), and percent change in plasma oxalate from baseline to M6 (average of months 3-6) (-39.5%, p=2.9 × 10−8). There were no serious or severe adverse events. The most common adverse events related to lumasiran were mild, transient injection site reactions.

Conclusion

Lumasiran resulted in clinically meaningful, rapid, sustained, and statistically significant reductions in urinary and plasma oxalate levels compared to placebo during the six-month double-blind period. Lumasiran has a favorable safety profile.

Manipulation of Alcohol and Short-Chain Fatty Acids in the Metabolome of Commensal and Virulent Klebsiella pneumoniae by Linolenic Acid

Endogenous alcohol produced by the gut microbiome is transported via the bloodstream to the liver for detoxification. Gut dysbiosis can result in chronic excess alcohol production that contributes to the development of hepatic steatosis. The aim of this study was to examine whether linolenic acid can manipulate the production of harmful alcohol and beneficial short-chain fatty acids (SCFAs) in the metabolome of commensal Klebsiella pneumoniae (K. pneumoniae) and the virulent K. pneumoniae K1 serotype. Glucose fermentation by the K. pneumoniae K1 serotype yielded increased production of alcohol and decreased SCFAs (especially acetate and propionate) compared to those of commensal K. pneumoniae. However, the use of linolenic acid instead of glucose significantly reduced alcohol and increased SCFAs in the fermentation media of the K. pneumoniae K1 serotype. The work highlights the value of shaping the microbial metabolome using linolenic acid, which can potentially regulate the gut–liver axis for the prevention and treatment of alcohol-induced liver diseases.

A preliminary survey of practice patterns across several European kidney stone centers and a call for action in developing shared practice

Currently an evidence-based approach to nephrolithiasis is hampered by a lack of randomized controlled trials. Thus, there is a need for common platforms for data sharing and recruitment of patients to interventional studies. A first step in achieving this objective would be to share practice methods and protocols for subsequent standardization in what is still a heterogeneous clinical field. Here, we present the results of a pilot survey performed across 24 European clinical kidney stone centers. The survey was distributed by a voluntary online questionnaire circulated between June 2017 and January 2018. About 46% of centers reported seeing on average 20 or more patients per month. Only 21% adopted any formal referral criteria. Centers were relatively heterogeneous in respect of the definition of an incident stone event. The majority (71%) adopted a formal follow-up scheme; of these, 65% included a follow-up visit at 3 and 12 months, and 41% more than 12 months. In 79% of centers some kind of imaging was performed systematically. 75% of all centers performed laboratory analyses on blood samples at baseline and during follow-up. All centers performed laboratory analyses on 24-h urine samples, the majority (96%) at baseline and during follow-up. There was good correspondence across centers for analyses performed on 24-h urine samples, although the methods of 24-h urine collection and analysis were relatively heterogeneous. Our survey among 24 European stone centers highlights areas of homogeneity and heterogeneity that will be investigated further. Our aim is the creation of a European network of stone centers sharing practice patterns and hosting a common database for research and guidance in clinical care.

Increased renal papillary density in kidney stone formers detectable by CT scan is a potential marker of stone risk, but is unrelated to underlying hypercalciuria

Several previous studies have reported an increase in Hounsfield unit density of the renal papillae in patients with nephrolithiasis compared with controls. Kidney stone formers (KSF) were found to have higher papillary and cortical density in both kidneys, irrespective of which side had calculi, and it was proposed that this might be related to the presence of underlying hypercalciuria. The current study was designed: (1) to determine whether recurrent KSF do have higher papillary density compared with healthy controls; (2) to test an association between higher renal papillary density and the presence of hypercalciuria in KSF. This retrospective case-matched controlled study was carried out at the Royal Free Hospital, London, UK. We investigated 111 patients, 57 of whom were KSF and 54 healthy controls. The CT attenuation values were measured within a 0.2 cm(2) area of the renal papilla in the upper, middle, and lower segments of each kidney, and were compared between KSF and non-stone formers, and between KSF with and without hypercalciuria. There were no significant differences in age and sex between groups. Papillary density was significantly higher in KSF by both crude and adjusted analyses (p < 0.001). However, there was no association between higher papillary density and hypercalciuria in KSF. The papillary density measured by CT is a useful, non-invasive tool to differentiate between KSF and healthy controls. The absence of any correlation between papillary density and hypercalciuria suggests that the presence of clinically significant underlying renal stone disease, rather than urinary metabolic abnormalities, correlates with radiologically detectable increased papillary density.

Selective screening for distal renal tubular acidosis in recurrent kidney stone formers: initial experience and comparison of the simultaneous furosemide and fludrocortisone test with the short ammonium chloride test

BACKGROUND

Distal renal tubular acidosis (dRTA) is associated with renal stone disease, and it often needs to be considered and excluded in some recurrent calcium kidney stone formers (KSFs). However, a diagnosis of dRTA, especially when 'incomplete', can be missed and needs to be confirmed by a urinary acidification (UA) test. The gold standard reference test is still the short ammonium chloride (NH₄Cl) test, but it is limited by gastrointestinal side effects and occasionally failure to ingest sufficient NH₄Cl. For this reason, the furosemide plus fludrocortisone (F+F) test has been proposed as an easier and better-tolerated screening test. The aim of the present study was to assess the usefulness of the F+F test as a clinical screening tool for dRTA in a renal stone clinic.

METHODS

We studied 124 patients retrospectively in whom incomplete dRTA was suspected: 71 had kidney stones only, 9 had nephrocalcinosis only and 44 had both. A total of 158 UA tests were performed: 124 F+F and 34 NH₄Cl; both tests were completed in 34 patients.

RESULTS

The mean age was 45.4 ± 15 years, and 49% of patients were male. The prevalence of complete and incomplete dRTAs was 7 and 13.7%, respectively. Of the 34 patients tested using both tests, 17 (50%) were abnormal and 4 (12%) were normal. Thirteen (39%) patients were abnormal by F+F, but normal by NH₄Cl [sensitivity 100% (95% CI 80-100), specificity 24% (95% CI 7-50), positive predictive value 57% (95% CI 37-75), negative predictive value 100% (95% CI 40-100)].

CONCLUSIONS

The F+F test is characterized by an excellent sensitivity and negative predictive value, and the diagnosis of incomplete dRTA can be excluded reliably in a patient who acidifies their urine normally with this test. However, its lack of specificity is a drawback, and if there is any doubt, an abnormal F+F test may need to be confirmed by a follow-up NH₄Cl test. Ideally, a prospective blinded study in unselected KSFs is needed to accurately assess the reliability of the F+F test in diagnosing, rather than excluding, dRTA.

A Brugada syndrome proband with compound heterozygote SCN5A mutations identified from a Chinese family in Singapore

AIMS

Brugada syndrome (BrS) is a rare heritable ventricular arrhythmia. Genetic defects in SCN5A, a gene that encodes the α-subunit of the sodium ion channel Nav1.5, are present in 15-30% of BrS cases. SCN5A remains by far, the highest yielding gene for BrS. We studied a young male who presented with syncope at age 11. This proband was screened for possible disease causing SCN5A mutations. The inheritance pattern was also examined amongst his first-degree family members.

METHODS AND RESULTS

The proband had a baseline electrocardiogram that showed Type 2 BrS changes, which escalated to a characteristic Type I BrS pattern during a treadmill test before polymorphic ventricular tachycardia onset at a cycle length of 250 ms. Mutational analysis across all 29 exons in SCN5A of the proband and first-degree relatives of the family revealed that the proband inherited a compound heterozygote mutation in SCN5A, specifically p.A226V and p.R1629X from each parent. To further elucidate the functional changes arising through these mutations, patch-clamp electrophysiology was performed in TSA201 cells expressing the mutated SCN5A channels. The p.A226V mutation significantly reduced peak sodium current (INa) to 24% of wild type (WT) whereas the p.R1629X mutation abolished the current. To mimic the functional state in our proband, functional expression of the compound variants A226V + R1629X resulted in overall peak INa of only 13% of WT (P < 0.01).

CONCLUSION

Our study is the first to report a SCN5A compound heterozygote in a Singaporean Chinese family. Only the proband carrying both mutations displayed the BrS phenotype, thus providing insights into the expression and penetrance of BrS in an Asian setting.

Effect of being overweight on urinary metabolic risk factors for kidney stone formation

BACKGROUND

The prevalence and incidence of kidney stone disease have increased markedly during the past several decades, and studies have demonstrated that inappropriate dietary habits are leading to more obesity and overweight (OW) in children and adults, which may be important in stone formation. Obese and OW patients share most of the same risk factors for cardiovascular morbidity, while the impact of being OW, rather than obese, on urinary metabolic parameters of kidney stone formers (KSF) is less well known. The aims of this study were to investigate urinary metabolic parameters, stone composition and probability of stone formation (Psf) in OW KSF when compared with normal weight (NW) and obese KSF.

METHODS

The kidney stone database for KSF attending a large metabolic stone clinic was investigated. Patients with a recorded BMI, confirmed diagnosis of kidney stone disease and full metabolic evaluation were divided into three categories: BMI ≤25.0 kg/m(2) (NW group), BMI 25-30 kg/m(2) (OW group) and BMI >30.0 kg/m(2) (obese group). Twenty-four hour urinary volume (U.Vol), pH (U.pH), calcium (U.Ca), oxalate (U.Ox), citrate (U.Cit), uric acid (U.UA), magnesium (U.Mg), sodium (U.Na) and potassium (U.K) excretions, along with stone composition and Psf, were then compared among the groups.

RESULTS

A total of 2132 patients were studied, of whom 833 (39%) were NW, 863 (40.5%) were OW and 436 (20.5%) were obese. OW and obese KSF were older (mean age 43 ± 15 in NW, 48 ± 13 in OW and 50 ± 12 years in obese; P for trend <0.001), demonstrated increased female predominance and higher prevalence of diabetes, hypertension and gout. There were no statistically significant differences in U.Vol and U.Mg among the groups. However, significantly higher levels of U.Ca, U.Ox, U.Cit, by crude analysis, and U.UA (3.3 ± 1.1 versus 3.8 ± 1.2 versus 4.0 ± 1.2 mmol/L; P < 0.001 for trend), U.Na (151 ± 57 versus 165 ± 60 versus 184 ± 63 mmol/L; P < 0.001 for trend), and lower U.pH (6.3 ± 0.5 versus 6.1 ± 0.5 versus 6.0 ± 0.6; P < 0.001 for trend) by both crude and multivariate adjusted analysis models were demonstrated in OW and obese KSF. Stone composition data (N = 640) showed a significantly higher incidence of uric acid stones in OW and obese groups (P for trend < 0.001). In addition, higher Psf for CaOx, UA and CaOx/UA stone types were detected in OW and obese compared with NW KSF.

CONCLUSIONS

Similar to obese KSF, OW KSF show clear alterations in metabolic urinary profiles that are associated with increased overall risk of stone formation. This greater risk is primarily due to raised U.UA and U.Na, lower U.pH and higher prevalence of hypercalciuria, along with unchanged levels of the commonly measured urinary lithogenesis inhibitors. Moreover, our study established a higher incidence of uric acid, but not calcium, stones in OW KSF. Thus, appropriate evaluation and follow-up may be warranted even in OW patients who are at risk of increased stone formation. Whether modest weight loss in OW KSF will have a favourable impact on their metabolic urinary profiles and thereby diminish the risk of further stone formation needs exploring.

Hypertonic saline reduces vascular leakage in a mouse model of severe dengue

Dengue (DEN) is a mosquito-borne viral disease and represents a serious public health threat and an economical burden throughout the tropics. Dengue clinical manifestations range from mild acute febrile illness to severe DEN hemorrhagic fever/DEN shock syndrome (DHF/DSS). Currently, resuscitation with large volumes of isotonic fluid remains the gold standard of care for DEN patients who develop vascular leakage and shock. Here, we investigated the ability of small volume of hypertonic saline (HTS) suspensions to control vascular permeability in a mouse model of severe DEN associated with vascular leakage. Several HTS treatment regimens were considered and our results indicated that a single bolus of 7.5% NaCl at 4 mL per kg of body weight administered at the onset of detectable vascular leakage rapidly and significantly reduced vascular leak for several days after injection. This transient reduction of vascular leakage correlated with reduced intestine and liver damage with restoration of the hepatic functions, and resulted in delayed death of the infected animals. Mechanistically, we showed that HTS did not directly impact on the viral titers but resulted in lower immune cells counts and decreased systemic levels of soluble mediators involved in vascular permeability. In addition, we demonstrated that neutrophils do not play a critical role in DEN-associated vascular leakage and that the therapeutic effect of HTS is not mediated by its impact on the neutrophil counts. Together our data indicate that HTS treatment can transiently but rapidly reduce dengue-associated vascular leakage, and support the findings of a recent clinical trial which evaluated the efficacy of a hypertonic suspension to impact on vascular permeability in DSS children.

Activation of neurokinin-1 receptors up-regulates substance P and neurokinin-1 receptor expression in murine pancreatic acinar cells

Acute pancreatitis (AP) has been associated with an up-regulation of substance P (SP) and neurokinin-1 receptor (NK1R) in the pancreas. Increased SP-NK1R interaction was suggested to be pro-inflammatory during AP. Previously, we showed that caerulein treatment increased SP/NK1R expression in mouse pancreatic acinar cells, but the effect of SP treatment was not evaluated. Pancreatic acinar cells were obtained from pancreas of male swiss mice (25–30 g). We measured mRNA expression of preprotachykinin-A (PPTA) and NK1R following treatment of SP (10⁻⁶M). SP treatment increased PPTA and NK1R expression in isolated pancreatic acinar cells, which was abolished by pretreatment of a selective NK1R antagonist, CP96,345. SP also time dependently increased protein expression of NK1R. Treatment of cells with a specific NK1R agonist, GR73,632, up-regulated SP protein levels in the cells. Using previously established concentrations, pre-treatment of pancreatic acinar cells with Gö6976 (10 nM), rottlerin (5 μM), PD98059 (30 μM), SP600125 (30 μM) or Bay11-7082 (30 μM) significantly inhibited up-regulation of SP and NK1R. These observations suggested that the PKC-ERK/JNK-NF-κB pathway is necessary for the modulation of expression levels. In comparison, pre-treatment of CP96,345 reversed gene expression in SP-induced cells, but not in caerulein-treated cells. Overall, the findings in this study suggested a possible auto-regulatory mechanism of SP/NK1R expression in mouse pancreatic acinar cells, via activation of NK1R. Elevated SP levels during AP might increase the occurrence of a positive feedback loop that contributes to abnormally high expression of SP and NK1R.

In vivo evaluation of an ultra-thin polycaprolactone film as a wound dressing

The use of ultra-thin films as dressings for cutaneous wounds could prove advantageous in terms of better conformity to wound topography and improved vapour transmission. For this purpose, ultra-thin poly(epsilon-caprolactone) (PCL) films of 5-15 microm thickness were fabricated via a biaxial stretching technique. To evaluate their in vivo biocompatibility and feasibility as an external wound dressing, PCL films were applied over full and partial-thickness wounds in rat and pig models. Different groups of PCL films were used: untreated, NaOH-treated, untreated with fibrin, NaOH-treated with perforations, and NaOH-treated with fibrin and S-nitrosoglutathione. Wounds with no external dressings were used as controls. Wound contraction rate, histology and biomechanical analyses were carried out. Wounds re-epithelialized completely at a comparable rate. Formation of a neo-dermal layer and re-epithelialization were observed in all the wounds. A lower level of fibrosis was observed when PCL films were used, compared to the control wounds. Ultimate tensile strength of the regenerated tissue in rats reached 50-60% of that in native rat skin. Results indicated that biaxially-stretched PCL films did not induce inflammatory reactions when used in vivo as a wound dressing and supported the normal wound healing process in full and partial-thickness wounds.

Role of protein kinase C in caerulein induced expression of substance P and neurokinin-1-receptors in murine pancreatic acinar cells

Substance P (SP) is involved in the pathophysiology of acute pancreatitis (AP) via binding to its high-affinity receptor, neurokinin-1-receptor (NK1R). An up-regulation of SP and NK1R expression was observed in experimental AP and in caerulein-stimulated pancreatic acinar cells. However, the mechanisms that lead to this up-regulation are not fully understood. In this study, we showed the role of protein kinase C (PKC) in caerulein-induced SP and NK1R production in isolated mouse pancreatic acinar cells. Caerulein (10(-7) M) stimulation rapidly activated the conventional PKC-α and novel PKC-δ as observed by the phosphorylation of these molecules. Pre-treatment of pancreatic acinar cells with Gö6976 (1-10 nM) and rottlerin (1-10 μM) inhibited PKC-α and PKC-δ phosphorylation, respectively, but not the other way round. At these concentrations used, PKC-α and PKC-δ inhibition reversed the caerulein-induced up-regulation of SP and NK1R, indicating an important role of PKCs in the modulation of SP and NK1R expression. Further experiments looking into signalling mechanisms showed that treatment of pancreatic acinar cells with both Gö6976 and rottlerin inhibited the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK). Inhibition of PKC-α or PKC-δ also affected caerulein-induced transcription factor activation, as represented by nuclear factor-κB and AP-1 DNA-binding activity. The findings in this study suggested that PKC is upstream of the mitogen-activated protein kinases and transcription factors, which then lead to the up-regulation of SP/NK1R expression in caerulein-treated mouse pancreatic acinar cells.

Lactobacillus rhamnosus GG secreting an antigen and Interleukin-2 translocates across the gastrointestinal tract and induces an antigen specific immune response

Lactobacillus rhamnosus strain GG (LGG) is a probiotic organism. In this present study, LGG that express the green fluorescence protein (LGG-GFP) and IL-2 and GFP as a fusion protein (LGG-IL-2-GFP) were used to examine bacterial uptake and the immune response induced by oral immunization. Using TEM to examine the intestinal tissue, the Lactobacilli were localized in M cells and in venules. After oral immunization, most of the bacteria were excreted in feces only a small fraction (0.15%) was retained in the intestine at 48 hr. However, more LGG-IL-2-GFP was found in the MLN and spleen than LGG-GFP. The loop ligation method was used to evaluate LGG uptake and both LGG-GFP and LGG-IL-2-GFP were found to translocate at the same rate. Analysis of LGG internalization in J774 macrophage cells indicated that IL-2 increased survival of LGG and this may explain the increased presence of these bacteria in the MLN for a longer period. After oral immunization, specific mucosal antibody production as well as GFP specific CTL activity was demonstrated. IL-2 co-expression with GFP further enhanced antibody production and CTL activity. In conclusion, Lactobacillus rhamnosus GG expressing an antigen could generate an effective immune response to the antigen and IL-2 improved the response generated probably by increasing LGG expressing antigen survival in immune cells.

Effect of blast exposure on the brain structure and cognition in Macaca fascicularis

Blast injury to the brain is one of the major causes of death and can also significantly affect cognition and physical and psychological skills in survivors of blast. The complex mechanisms via which blast injury causes impairment of cognition and other symptoms are poorly understood. In this study, we investigated the effects of varying degrees of primary blast overpressure (BOP; 80 and 200 kPa) on the pathophysiological and magnetic resonance imaging (MRI) changes and neurocognitive performance as assessed by the monkey Cambridge Neuropsychological Test Automated Battery (mCANTAB) in non-human primates (NHP). The study aimed to examine the effects of neurobehavioral and histopathological changes in NHP. MRI and histopathology revealed ultrastructural changes in the brain, notably in the Purkinje neurons in the cerebellum and pyramidal neurons in the hippocampus, which were most vulnerable to the blast. The results correlated well with the behavioral changes and changes in motor coordination and working memory of the affected monkeys. In addition, there was white matter damage affecting myelinated axons, astrocytic hypertrophy, and increased aquaporin-4 (AQP-4) expression in astrocytes, suggesting cerebral edema. Increased apoptosis appeared to involve astrocytes and oligodendrocytes in the animals following blast exposure. The small sample size could have contributed to the non-significant outcome in cognitive performance post-blast and limited quantitative analyses. Nevertheless, the study has provided initial descriptive changes for establishing a primary BOP threshold for brain injury to serve as a useful platform for future investigations that aim to estimate brain injury potential and set safe limits of exposure.

The role of neutral endopeptidase in caerulein-induced acute pancreatitis

Substance P (SP) is well known to promote inflammation in acute pancreatitis (AP) by interacting with neurokinin-1 receptor. However, mechanisms that terminate SP-mediated responses are unclear. Neutral endopeptidase (NEP) is a cell-surface enzyme that degrades SP in the extracellular fluid. In this study, we examined the expression and the role of NEP in caerulein-induced AP. Male BALB/c mice (20-25 g) subjected to 3-10 hourly injections of caerulein (50 μg/kg) exhibited reduced NEP activity and protein expression in the pancreas and lungs. Additionally, caerulein (10(-7) M) also downregulated NEP activity and mRNA expression in isolated pancreatic acinar cells. The role of NEP in AP was examined in two opposite ways: inhibition of NEP (phosphoramidon [5 mg/kg] or thiorphan [10 mg/kg]) followed by 6 hourly caerulein injections) or supplementation with exogenous NEP (10 hourly caerulein injections, treatment of recombinant mouse NEP [1 mg/kg] during second caerulein injection). Inhibition of NEP raised SP levels and exacerbated inflammatory conditions in mice. Meanwhile, the severity of AP, determined by histological examination, tissue water content, myeloperoxidase activity, and plasma amylase activity, was markedly better in mice that received exogenous NEP treatment. Our results suggest that NEP is anti-inflammatory in caerulein-induced AP. Acute inhibition of NEP contributes to increased SP levels in caerulein-induced AP, which leads to augmented inflammatory responses in the pancreas and associated lung injury.

Association between an intronic apolipoprotein E polymorphism and bone mineral density in Singaporean Chinese females

INTRODUCTION

Apolipoprotein E (ApoE) is implicated in the pathogenesis of osteoporosis.

OBJECTIVE

To investigate possible association of the non-classical APOE gene +113C/G (rs440446) intron 1 enhancer polymorphism with bone mineral density (BMD) in a homogeneous Chinese population in Singapore.

METHODS

A total of 655 volunteers, males and females, aged between 31 and 72 years, from the public participated. BMD was measured using dual-energy X-ray absorptiometry and APOE +113C/G (rs440446) genotypes were determined by Sequenom MassARRAY system. To adjust for potential confounders, anthropometric, demographic, and lifestyle determinants were obtained, and serum lipids and E(2) were measured.

RESULTS

The +113C/G (rs440446) polymorphism within the APOE gene was associated with BMD in Chinese Singaporean females only. Females with the heterozygous CG genotype were significantly associated with reduced total, lumbar spine, and femoral neck of hip BMD, after multilevel adjustment of confounders. The association was stronger in the spine than in the hip. When females were stratified according to WHO classification for osteoporosis, those with CG and GG genotypes had increased risk (OR 3.50 and 2.22, respectively) of developing osteopenia/osteoporosis in the lumbar spine. Serum lipids did not explain the influence of APOE +113 C/G (rs440446) on BMD.

CONCLUSION

This study demonstrated an association between APOE +113C/G (rs440446) polymorphism with measures of BMD in Singaporean Chinese females.

Role of hydrogen sulfide in severe burn injury-induced inflammation in mice

Endogenous hydrogen sulfide (H(2)S) is naturally synthesized in many types of mammalian cells from L-cysteine in the reactions catalyzed by cystathionine-β-synthase and cystathionine-γ-lyase (CSE). H(2)S has been demonstrated to play a proinflammatory role in various animal models of hindpaw edema, acute pancreatitis, lipopolysaccharide-induced endotoxemia and cecal ligation, and puncture-induced sepsis. Full-thickness burns that exceed 25% of the total body surface area (TBSA) produce a profound systemic inflammatory reaction characterized by leukocyte activation and plasma leakage in the microvasculature of tissues and organs remote from the wound. The aim of this study was to investigate the effect of local burn injury on induced distant organ endogenous H(2)S release and expression of CSE. Male BALB/c mice were subjected to 30% TBSA full-thickness burn and treated with saline (administered intraperitoneally [i.p.]); DL-propargylglycine (PAG, 50 mg/kg i.p.), which is a CSE inhibitor; or sodium hydrosulfide (NaHS, 10 mg/kg i.p.), which is an H(2)S donor. PAG was administered either 1 h before or 1 h after the burn injury, whereas NaHS was given at the same time as the burn injury. Measurements of liver myeloperoxidase (MPO) activities, liver H(2)S-synthesizing activity, plasma H(2)S level and liver and lung CSE mRNA expression and histological examination of tissues were performed after burn injury. Burn injury significantly increased the plasma H(2)S level and liver H(2)S synthesis 8 h after burn compared with the sham group. Burn injury also resulted in a significant upregulation of CSE mRNA in liver and lung. Prophylactic as well as therapeutic administration of PAG significantly reduced burn-associated systemic inflammation, as evidenced by MPO activity and histological changes in liver and lung. Injection of NaHS significantly aggravated burn-associated systemic inflammation. Therefore, our findings show for the first time the role of H(2)S in contributing to inflammatory damage after burn injury.

Retrospective population pharmacokinetic/pharmacodynamic analysis of pyridostigmine, a cholinesterase inhibitor, in Chinese males

Objectives

We have characterised the population pharmacokinetics-pharmacodynamics of pyridostigmine given as pyridostigmine bromide.

Methods

Over three days 50 healthy Chinese male subjects each received seven doses of 30 mg pyridostigmine bromide orally (3 times 10 mg every 8 h). Plasma concentrations of pyridostigmine and red blood cell acetylcholinesterase (AChE) activity were determined at various times within the eight hours after the first and the seventh doses. The resulting pharmacokinetic data were fitted to a single compartment open model with first-order absorption and elimination. The pharmacodynamics were modelled using an inhibitory Emax model. The potential influence of demographic and biological covariates on the model parameters was investigated. Nonlinear mixed effects modelling was performed using NONMEM.

Key findings

The apparent clearance and volume of distribution as well as absorption rate constant of plasma pyridostigmine were estimated to be 136 1/h, 130 1 and 0.68 1/h, respectively. The maximum red blood cell AChE activity decrease (Emax) and plasma pyridostigmine concentration producing 50% of this reduction (EC50) were estimated to be 9.32 AChE units per gram haemoglobin and 51.9 ng/ml, respectively. None of the tested covariates were found to be correlated with any of the model parameters. Dosing simulations suggested that 30 mg repeated every six hours might be needed to achieve steady-state trough percentage inhibition above the recommended 10% in healthy Chinese males.

Conclusions

The pharmacokinetics and the effects of pyridostigmine on red blood cell AChE activity were described using a mixed effects model. For Chinese males, the dosing interval may have been shorter than that recommended for the Caucasian population. Additional studies are needed to confirm these findings.

Early protection from burn-induced acute lung injury by deletion of preprotachykinin-A gene

RATIONALE

Burn-induced acute lung injury (ALI) is a common clinical disorder associated with high mortality even in the absence of inhalational injury. Identification of endogenous triggers that mediate the early onset of remote ALI after burn represents an important goal but remains poorly defined.

OBJECTIVES

We investigated the role of proinflammatory neuropeptide, substance P (SP), in instigating remote ALI and its effects on respiratory function early after severe local burn injury.

METHODS

A 30% total body surface area full-thickness burn was induced in wild-type (WT) mice, preprotachykinin-A (PPT-A) gene deficient mice, which encodes for SP, and PPT-A(-/-) mice challenged with exogenous SP, followed by ALI and lung function analysis.

MEASUREMENTS AND MAIN RESULTS

Endogenous SP production was heightened in burn-injured WT mice, which induced significant elevation of proinflammatory cytokines, chemokines, and endothelial adhesion molecules concurrent with disruption of pulmonary permeability barrier, excessive neutrophil infiltration, and severe ALI. Additionally, decreased neutral endopeptidase and elevated matrix metalloproteinase-9 were evident. Notably, disruption of respiratory function demonstrates a critical role of SP in lungs after burn. These effects were significantly attenuated in PPT-A(-/-) mice, whereas the exogenous administration of SP to PPT-A(-/-) mice restored the inflammatory response and ALI. Furthermore, analysis of neurokinin-1-receptor (NK1R), to which SP binds preferentially, revealed that SP in conjunction with burn injury regulates NK1R expression.

CONCLUSIONS

We show that the absence of a single endogenous factor, SP, significantly provides early protection against burn-induced ALI in mice with marked improvement in respiratory function. Thereby, the blockade of SP may be beneficial in preventing early inflammation and ALI in patients with critical burn injuries.

Retrospective population pharmacokinetic/pharmacodynamic analysis of pyridostigmine, a cholinesterase inhibitor, in Chinese males

OBJECTIVES

We have characterised the population pharmacokinetics-pharmacodynamics of pyridostigmine given as pyridostigmine bromide.

METHODS

Over three days 50 healthy Chinese male subjects each received seven doses of 30 mg pyridostigmine bromide orally (3 x 10 mg every 8 h). Plasma concentrations of pyridostigmine and red blood cell acetylcholinesterase (AChE) activity were determined at various times within the eight hours after the first and the seventh doses. The resulting pharmacokinetic data were fitted to a single compartment open model with first-order absorption and elimination. The pharmacodynamics were modelled using an inhibitory E(max) model. The potential influence of demographic and biological covariates on the model parameters was investigated. Nonlinear mixed effects modelling was performed using NONMEM.

KEY FINDINGS

The apparent clearance and volume of distribution as well as absorption rate constant of plasma pyridostigmine were estimated to be 136 l/h, 130 l and 0.68 1/h, respectively. The maximum red blood cell AChE activity decrease (E(max)) and plasma pyridostigmine concentration producing 50% of this reduction (EC50) were estimated to be 9.32 AChE units per gram haemoglobin and 51.9 ng/ml, respectively. None of the tested covariates were found to be correlated with any of the model parameters. Dosing simulations suggested that 30 mg repeated every six hours might be needed to achieve steady-state trough percentage inhibition above the recommended 10% in healthy Chinese males.

CONCLUSIONS

The pharmacokinetics and the effects of pyridostigmine on red blood cell AChE activity were described using a mixed effects model. For Chinese males, the dosing interval may have been shorter than that recommended for the Caucasian population. Additional studies are needed to confirm these findings.

Sepsis as a model of SIRS

Sepsis describes a complex clinical syndrome that results from the host inability to regulate the inflammatory response against infection. Despite more than 20 years of extensive study, sepsis and excessive systemic inflammatory response syndrome (SIRS) are still the leading cause of death in intensive care units. The clinical study of sepsis and new therapeutics remains challenging due to the complexity of this disease. Therefore, many animal models have been employed to investigate the pathogenesis of sepsis and to preliminarily test potential therapeutics. However, so far, most therapeutics that have shown promising results in animal models failed in human clinical trials. In this chapter we will present an overview of different experimental animal models of sepsis and compare their advantages and disadvantage. The studies in animal models have greatly improved our understanding about the inflammatory mediators in sepsis. In this chapter we will also highlight the roles of several critical mediators including TNF-a , IL-1b , IL-6, chemokines, substance P, hydrogen sulfide and activated protein C in animal models of sepsis as well as in clinical studies.

Animal models of smoke inhalation induced injuries

Smoke inhalation injury is the leading cause of mortality from structural fires, as a result of complications such as systemic inflammatory response syndrome and chronic obstructive pulmonary disease, which can be caused by a localized or systemic response. In this review, the pathophysiology of smoke inhalation injury, along with the characteristics found in clinical settings, common animal models, current treatment methods and future potential therapeutics are discussed.

Systemic inflammatory response following acute traumatic brain injury

The early, delayed, and systemic effects of acute traumatic brain injury (TBI) are the result of inflammatory mediators which initiate systemic inflammatory response syndrome (SIRS), subsequent complement deficits and coagulopathy. Once SIRS is triggered by acute inflammation, it can detrimentally self-propagate. Systemic inflammation causes tissue damage leading to further inflammation and damage, leaving the body in a vicious cycle of hyperinflammation. Therefore, important inflammatory mediators like interleukin (IL)-1 beta, IL-6 and tumour necrosis factor (TNF) alpha, are targeted in compensatory anti-inflammatory response syndrome (CARS) in an attempt to control the development of SIRS. The hypothalamus-pituitary (HPA)-axis and sympathetic nervous system (SNS) efferent limbs in CARS provide negative feedback for the production of inflammatory mediators. However, in the case of acute TBI, the activation of CARS often leads to the complication of immunosuppression which may result in multi-organ dysfunction syndrome (MODS) and mortality. In light of this, the activation of the SIRS following acute TBI does not bode well. If left uncontrolled, multiple systems will be implicated making it difficult to remedy.

Polymeric micelles anchored with TAT for delivery of antibiotics across the blood-brain barrier

Polymeric micelles self-assembled from cholesterol-conjugated poly(ethylene glycol) (PEG) and anchored with transcriptional activator TAT peptide (TAT-PEG-b-Col) were fabricated for delivery of antibiotics across the blood-brain barrier (BBB). Ciprofloxacin, which demonstrated a high bactericidal effect, was efficiently loaded into the micelles by a membrane dialysis method. The ciprofloxacin-loaded micelles were characterized via dynamic light scattering and SEM. The micelles were spherical in nature, having an average diameter of smaller than 180 nm. Sustained release of ciprofloxacin was achieved over 6 h in phosphate-buffered saline (pH 7.4) at 37 degrees C. Confocal laser scanning microscopy reveals that the uptake of Fluorescein 5-isothiocyanate (FITC)-loaded TAT-PEG-b-Col micelles by human astrocytes was much higher than that of free FITC. Animal studies proved that these micelles crossed the BBB and entered the brain. The TAT-conjugated micelles may be used to deliver antibiotics across the BBB for treatment of brain infections.

Applications of microarrays in pathogen detection and biodefence

The microarray is a platform with wide-ranging potential in biodefence. Owing to the high level of throughput attainable through miniaturization, microarrays have accelerated the ability to respond in an epidemic or crisis. Extending beyond diagnostics, recent studies have applied microarrays as a research tool towards understanding the etiology and pathogenicity of dangerous pathogens, as well as in vaccine development. The original emphasis was on DNA microarrays, but the range now includes protein, antibody and carbohydrate microarrays, and research groups have exploited this diversity to further extend microarray applications in the area of biodefence. Here, we discuss the impact and contributions of the growing range of microarrays and emphasize the concepts that might shape the future of biodefence research.

The neuropeptide substance P is a critical mediator of burn-induced acute lung injury

The classical tachykinin substance P (SP) has numerous potent neuroimmunomodulatory effects on all kinds of airway functions. Belonging to a class of neuromediators targeting not only residential cells but also inflammatory cells, studying SP provides important information on the bidirectional linkage between how neural function affects inflammatory events and, in turn, how inflammatory responses alter neural activity. Therefore, this study aimed to investigate the effect of local burn injury on inducing distant organ pulmonary SP release and its relevance to lung injury. Our results show that burn injury in male BALB/c mice subjected to 30% total body surface area full thickness burn augments significant production of SP, preprotachykinin-A gene expression, which encodes for SP, and biological activity of SP-neurokinin-1 receptor (NK1R) signaling. Furthermore, the enhanced SP-NK1R response correlates with exacerbated lung damage after burn as evidenced by increased microvascular permeability, edema, and neutrophil accumulation. The development of heightened inflammation and lung damage was observed along with increased proinflammatory IL-1beta, TNF-alpha, and IL-6 mRNA and protein production after injury in lung. Chemokines MIP-2 and MIP-1alpha were markedly increased, suggesting the active role of SP-induced chemoattractants production in trafficking inflammatory cells. More importantly, administration of L703606, a specific NK1R antagonist, 1 h before burn injury significantly disrupted the SP-NK1R signaling and reversed pulmonary inflammation and injury. The present findings show for the first time the role of SP in contributing to exaggerated pulmonary inflammatory damage after burn injury via activation of NK1R signaling.

Hydrogen sulfide acts as an inflammatory mediator in cecal ligation and puncture-induced sepsis in mice by upregulating the production of cytokines and chemokines via NF-κB

Recent studies have implied that hydrogen sulfide (H2S) plays a crucial role in several inflammatory conditions. However, so far little is known about the mechanism by which H2S provokes the inflammatory response in sepsis. Thus the aim of this study was to investigate if H2S regulates sepsis-associated systemic inflammation and production of proinflammatory mediators via the activation of NF-κB. Male Swiss mice were subjected to cecal ligation and puncture (CLP)-induced sepsis and treated with dl-propargylglycine (PAG; 50 mg/kg ip), NaHS (10 mg/kg ip), or saline. PAG, an inhibitor of H2S formation, was administered either 1 h before or 1 h after CLP, whereas NaHS, an H2S donor, was given at the time of CLP. Some normal mice were given NaHS (10 mg/kg ip) to induce lung inflammation with or without pretreatment with the NF-κB inhibitor BAY 11-7082. Eight hours after CLP, both prophylactic and therapeutic administration of PAG significantly reduced the mRNA and protein levels of IL-1β, IL-6, TNF-α, monocyte chemotactic protein-1, and macrophage inflammatory protein-2 in lung and liver coupled with decreased activation and translocation of NF-κB in lung and liver. Inhibition of H2S formation also significantly reduced lung permeability and plasma alanine aminotransferase activity. In contrast, injection of NaHS significantly aggravated sepsis-associated systemic inflammation and increased NF-κB activation. In addition, H2S-induced lung inflammation was blocked by BAY 11-7082. Therefore, H2S upregulates the production of proinflammatory mediators and exacerbates the systemic inflammation in sepsis through a mechanism involving NF-κB activation.

2', 3'-Cyclic nucleotide 3'-phosphodiesterase cells derived from transplanted marrow stromal cells and host tissue contribute to perineurial compartment formation in injured rat spinal cord

Transdifferentiation of transplanted marrow stromal cells (MSCs) and reactive changes of glial cells in a completely transected rat spinal cord were examined. Marrow stromal cells exhibited 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) at the plasma membrane and this has allowed their identification after transplantation by immunoelectron microscopy. In the control rats, the lesion site showed activated microglia/neural macrophages and some elongated cells, whose cytoplasm was immunoreactive for CNP. Cells designated as CNP1 and apparently host-derived expressed CXCR4. In experimental rats receiving MSCs transplantation, CNP1 cells were increased noticeably. This was coupled with the occurrence of a different subset of CNP cells whose plasma membrane was CNP-immunoreactive and expressed CXCR4. These cells, designated as CNP2, enclosed both myelinated and unmyelinated neurites thus assuming a spatial configuration resembling that of Schwann cells. A remarkable feature was the extensive ramifications of CNP1 cells with long filopodia processes delineating the CNP2 cells and their associated neurites, forming many perineurial-like compartments. Present results have shown that CNP2 cells considered to be MSCs-derived can transform into cells resembling Schwann cells based on their spatial relation with the regenerating nerve fibers, whereas the CNP1 glial cells participate in formation of perineurial compartments, probably serving as conduits to guide the nerve fiber growth. The chemotactic migration of CNP cells either derived from host tissue or MSCs bearing CXCR4 may be attracted by stromal derived factor-1alpha (SDF-1alpha) produced locally. The coordinated cellular interaction between transplanted MSCs and local glial cells may promote the growth of nerve fibers through the lesion site.

Alterations in spatial learning and memory after forced exercise

Exercise has been shown to influence learning and memory. Most studies were performed with a voluntary running paradigm (e.g. running wheel) in mice. However, such effects of exercise on learning and memory are less well demonstrated using a forced running paradigm (e.g. treadmill). The present study was designed to examine the effects of 12 weeks of forced treadmill running on learning and memory performance in rats. We have previously shown that forced running resulted in qualitative and quantitative changes in the cholinergic neurons of the horizontal diagonal band of Broca (HDB) in the septum. This study was conducted in order to determine whether or not these changes occur simultaneously with enhanced learning and memory. The one-day version of the Morris water maze (MWM) test [Frick, K.M., Stillner, E.T., Berger-Sweeney, J., 2000. Mice are not little rats: species differences in a one-day water maze task. NeuroReport 11, 3461-3465] was used to test spatial learning and memory after the exercise period. Our data showed that runners displayed better spatial learning and memory when compared to nonrunners. This was evidently shown by a reduction in the time required for spatial acquisition (p<0.05) and superior probe trial performance (p<0.05). A shorter distance swam by the runners also suggested improved learning over the nonrunners (p<0.05). In an attempt to revalidate our earlier quantitative results, we used design-based stereology (DBS) to estimate the number of cholinergic neuronal profile population in the medial septum and diagonal band (MSDB). We confirmed that forced running increased the cholinergic neuronal profile subpopulation in the HDB (Coefficient of Error<0.2). Taken together, these results indicate that forced exercise could influence learning and memory with a concomitant increase in the number of cholinergic neurons in the HDB.

Adult bone marrow cells differentiate into neural phenotypes and improve functional recovery in rats following traumatic brain injury

This study aims to investigate the therapeutic potential of adult bone marrow stromal cells (BMSCs). Exposed to a cocktail of induction medium, some BMSCs could differentiate into cell types with phenotypes of neural lineages in vitro. These cells expressed neural markers nestin, GFAP, 68-kDa neurofilament and beta-tubulin III as detected by immunohistochemistry and RT-PCR. Fluorescence-labeled cells were injected intravenously at 72 h after traumatic brain injury. Transplanted cells survived and migrated to the ipsilateral cerebral cortex at different time points after injection. They were immunopositive for neuronal marker MAP-2, oligodendrocyte marker CNPase, astrocytic maker GFAP or microglial marker OX-42 in vivo. In rats receiving BMSC transplants, there were significant improvements in motor and neurological functions when compared with the control groups. Hence, the therapeutic potential of BMSCs for traumatic brain injury is further amplified.

Hippocampal theta state in relation to formalin nociception

In the present study using extracellular electrophysiological recording techniques, we explored the temporal characteristics of hippocampal theta activation in relation to formalin nociception. Results indicate that, compared to hind paw injection of saline, formalin injection in behaving rat evoked biphasic increase in duration of dorsal CA1 theta. Such an increase broadly paralleled animal biphasic behavioral activation, especially lick and moment-to-moment agitated behaviors. Correspondingly, theta-modulated cell firing was observed following formalin injection in anesthetized rat. The formalin-induced theta activation in behaving rat was most marked during peak of theta activation in the 2nd theta state (11-40 min post-injection) comprising 73% of the time in the 5 min block. An increase in theta peak frequency was also observed with respect to pre-injection control. However, the peak of theta in the 2nd theta state mostly preceded the peak of lick and flinch of the affected paw. In the 41-60 min, following formalin injection while the animals displayed robust nociceptive flinching and lifting, the theta activity approached control levels. Furthermore, the theta peak frequency at peak of theta was higher than the corresponding values of sustained theta observed in correlation with the nociceptive behaviors; in contrast, high frequency theta rhythm was observed during formalin-induced other moment-to-moment agitated behaviors. These findings favor the notion that in the formalin model the theta state of the hippocampus reflects a neural drive that is dissociated from the duration of nociceptive experience and is not selective to the typical nociceptive indices of lick, flinch, and lift of the injured paw.