Myalgic encephalomyelitis/chronic fatigue syndrome from current evidence to new diagnostic perspectives through skeletal muscle and metabolic disturbances

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a demanding medical condition for patients and society. It has raised much more public awareness after the COVID-19 pandemic since ME/CFS and long-COVID patients share many clinical symptoms such as debilitating chronic fatigue. However, unlike long COVID, the etiopathology of ME/CFS remains a mystery despite several decades' research. This review moves from pathophysiology of ME/CFS through the compelling evidence and most interesting hypotheses. It focuses on the pathophysiology of skeletal muscle by proposing the hypothesis that skeletal muscle tissue offers novel opportunities for diagnosis and treatment of this syndrome and that new evidence can help resolve the long-standing debate on terminology.

Nutritional physiology and body composition changes during a rapid ascent to high altitude

Exposure to high altitude might cause the body to adapt with negative energy and fluid balance that compromise body composition and physical performance. In this field study involving 12 healthy adults, sex-balanced, and aged 29 ± 4 years with a body mass index of 21.6 ± 1.8 kg/m2, we investigated the effects of a 4-day trekking up to 4556 m a.s.l. on Monte Rosa (Alps, Italy). The food intake was recorded using food diaries and nutrient averages were calculated. The bio-impedance analysis was performed at low and high altitudes, and a wearable biosensor (Swemax) was used to track hydro-saline losses in two participants. Daily total energy intake was 3348 ± 386 kcal for males and 2804 ± 415 kcal for females (13%-14% protein, 35% fat, 44%-46% carbohydrates). Although there was a significant body weight loss (65.0 ± 9.3 vs. 64.2 ± 9.10 kg, p < 0.001, d = 1.398), no significant changes in body composition parameter were found but a trend in the increase of the bioelectrical phase angle in males (p = 0.059, d = -0.991). Body water percentage significantly changed (p = 0.026, η2 p = 0.440), but the absolute water did not, suggesting that the weight loss was not due to water loss. Salivary and urinary osmolality did not change. A reduction in sweat rate at higher altitudes was observed in both participants. Interestingly, salivary leptin increased (p = 0.014, η2 p = 0.510), and salivary ghrelin decreased (p = 0.036, η2 p  = 0.403). Therefore, the 4-day trekking at altitude of hypoxia exposure induced changes in satiety and appetite hormones. High altitude expeditions require more specific nutritional guidance, and using multiplex analysis could help in monitoring fluid balance and body composition.

Electromyographic signature of isometric squat in the highest refuge in Europe

Reports of electromyography during hypoxic exercise are contrasting, due to protocol and muscle diversity. This work aimed to investigate alterations in muscle activation and myoelectrical fatigue during exercise at high-altitude in those muscles primarily involved in trekking. Twelve young adults balanced by gender and age were tested at low (1,667 m) and high (4,554 m, "Capanna Margherita", Italy) altitude, during an isometric squat lasting 60 seconds. High-density surface electromyography was performed from the quadriceps of right limb. The root mean square (RMS), median frequency with its slope, and muscle fiber conduction velocity (MFCV) were computed. Neither males nor females showed changes in median frequency (Med: 36.13 vs 35.63 Hz) and its slope (Med: -9 vs -12 degree) in response to high-altitude trekking, despite a great inter-individual heterogeneity, nor differences were found for MFCV. RMS was not significantly equivalent, with greater values at low altitude (0.385 ± 0.104 mV) than high altitude (0.346 ± 0.090 mV). Unexpected results can be due either to a postural compensation of the whole body compensating for a relatively greater effort or to the inability to support muscle activation after repeated physical efforts.  Interesting results may emerge by measuring simultaneously electromyography, muscle oxygenation and kinematics comparing trekking at normoxia vs hypoxia.

Clinical features and health-threatening conditions of the trek to Capanna Margherita

BACKGROUND

Since trips to high altitude have become popular, reports on clinical and environmental characteristics during expeditions to popular destinations are needed.

METHODS

A group of 15 healthy adults was monitored during a trek to Capanna Margherita (4556 m). A hypoxic stress test was applied before the expedition started. Environmental characteristics were acquired with a portable device. Vital signs were compared at low and high altitude, and altitude sickness was diagnosed by the Lake Louise scoring system. Ocular symptoms and intraocular pressure were recorded.

RESULTS

Temperature ranged from -3.5 to 31.3 °C and relative humidity from 36 to 95% during the trek. Acute mountain sickness was diagnosed in 40% of participants, more frequently in women, and slightly associated with a greater drop in SpO<inf>2</inf>. Heart rate and blood pressure increased, while peripheral saturation and intraocular pressure decreased, in response to altitude hypoxia.

CONCLUSIONS

Rapid ascents, as in the most common expedition plans, should be carefully supervised because of the common occurrence of AMS, especially in women. Among organ districts, the eye should deserve more attention in high-altitude medicine. Analyses of environmental conditions, together with predictive methods and early identification of health-threatening conditions, are of great value in supporting further recreational, professional and scientific expeditions to the most intriguing altitude sites.

Endurance-dependent urinary extracellular vesicle signature: shape, metabolic miRNAs, and purine content distinguish triathletes from inactive people

Extracellular vesicles (EVs) enriched with bioactive molecules have gained considerable attention in nanotechnology because they are critical to intercellular communication while maintaining low immunological impact. Among biological matrices, urine has emerged as a noninvasive source of extracellular-contained liquid biopsy, currently of interest as a readout for physiological adaptations. Therefore, we aimed to evaluate chronic adaptations of endurance sport practice in terms of urinary EV parameters and evaluated by food consumption assessment. Two balanced groups of 13 inactive controls vs. triathlon athletes were enrolled; their urinary EVs were obtained by differential ultracentrifugation and analyzed by dynamic light scattering and transmission electron and atomic force microscopy. The cargo was analyzed by means of purine and miRNA content through HPLC-UV and qRT-PCR. Specific urinary EV signatures differentiated inactive versus endurance-trained in terms of peculiar shape. Particularly, a spheroid shape, smaller size, and lower roughness characterize EVs from triathletes. Metabolic and regulatory miRNAs often associated with skeletal muscle (i.e., miR378a-5p, miR27a-3p, miR133a, and miR206) also accounted for a differential signature. These miRNAs and guanosine in urinary EVs can be used as a readout for metabolic status along with the shape and roughness of EVs, novel informative parameters that are rarely considered. The network models allow scholars to entangle nutritional and exercise factors related to EVs' miRNA and purine content to depict metabolic signatures. All in all, multiplex biophysical and molecular analyses of urinary EVs may serve as promising prospects for research in exercise physiology.

Broadband Electrical Spectroscopy to Distinguish Single-Cell Ca2+ Changes Due to Ionomycin Treatment in a Skeletal Muscle Cell Line

Many skeletal muscle diseases such as muscular dystrophy, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and sarcopenia share the dysregulation of calcium (Ca²⁺) as a key mechanism of disease at a cellular level. Cytosolic concentrations of Ca²⁺ can signal dysregulation in organelles including the mitochondria, nucleus, and sarcoplasmic reticulum in skeletal muscle. In this work, a treatment is applied to mimic the Ca²⁺ increase associated with these atrophy-related disease states, and broadband impedance measurements are taken for single cells with and without this treatment using a microfluidic device. The resulting impedance measurements are fitted using a single-shell circuit simulation to show calculated electrical dielectric property contributions based on these Ca²⁺ changes. From this, similar distributions were seen in the Ca²⁺ from fluorescence measurements and the distribution of the S-parameter at a single frequency, identifying Ca²⁺ as the main contributor to the electrical differences being identified. Extracted dielectric parameters also showed different distribution patterns between the untreated and ionomycin-treated groups; however, the overall electrical parameters suggest the impact of Ca²⁺-induced changes at a wider range of frequencies.

Redox-based disruption of cellular hormesis and promotion of degenerative pathways: perspectives on ageing processes

The present work aims to link the redox and cell-centric theories of chronic processes in human biology, focusing on ageing. A synthetic overview of cellular redox pathways will be integrated by the concept of hormesis, which disruption leads to several physiopathological processes. The onset of age-related diseases due to the restriction of homeodynamic capacity will be herein considered in a redox fashion. Up-to-date arguments on hormetic agents, such as geroprotectors, dietary interventions, and physical exercise are refining the presented theoretical framework, integrated by insights from extracellular vesicles, microbiota, pollutants, and timing mechanisms. The broad concepts of exposome encompass the redox-based alteration of cellular hormesis for providing meaningful perspectives on redox biogerontology.

New Perspectives for Postmortem Human Satellite Cells of Different Embryological Origin

Human postmortem skeletal muscles are a unique source of satellite cells for skeletal muscle regenerative studies. Presomite and somite satellite cells obtained by postmortem muscles have been established as populations of human skeletal muscle precursor cells able to proliferate and differentiate in vitro. It is extremely interesting to have access to a large amount of postmortem human skeletal muscle precursor cells, especially from craniofacial as well as limb skeletal muscles in order to evaluate their potential application not only for the fundamental understanding of muscle physiology and diseases but also for drug testing in a challenging 3D-shaping muscles like skeletal muscle microphysiological systems.

Distancing Measures in COVID-19 Pandemic: Loneliness, More than Physical Isolation, Affects Health Status and Psycho-Cognitive Wellbeing in Elderly Patients with Chronic Obstructive Pulmonary Disease

Since the outbreak of the SARS-CoV-2 pandemic in 2020, many governments have been imposing confinement and physical distancing measures. No data exist on the effects of lockdowns on the health status of patients affected by chronic pathologies, specifically those with Chronic Obstructive Pulmonary Disease (COPD). Our study aims to establish variations across the psychological and cognitive profile of patients during the isolation period in Italy, in a cohort of patients affected by COPD, between February and May 2020. Forty patients with established COPD were comprehensively evaluated by geriatric multidimensional assessment before the spread of the epidemic in Italy, and submitted to a second evaluation during the subsequent lockdown. We assessed functional ability, basic and instrumental Activities of Daily Living (ADL and IADL), cognition and mood status. We compared the scores obtained at baseline against those obtained during the pandemic, and used mean differences for correlation with major clinical and functional indexes. The score differences from MMSE, ADL and IADL were statistically significant. Such differences were correlated to the presence of a caregiver and to the total number of family members living together. Remarkably, the loneliness dimension, more than the restrictions themselves, seemed to represent the major determinant of altered health status and depressed psycho-cognitive profile in our population. Also remarkably, we detected no correlation between the score variation and the respiratory function indexes of disease severity. The isolation measures adopted during the SARS-CoV-2 pandemic have triggered the classic clinical string associated to geriatric isolation, which leads to a deterioration of cognitive functions, independence and frailty levels in a population affected by a chronic degenerative disease, such as COPD. If considered from a multidimensional geriatric point of view, the individual benefit of isolation measures could be small or non-existent.

Consumption of extra-virgin olive oil rich in phenolic compounds improves metabolic control in patients with type 2 diabetes mellitus: a possible involvement of reduced levels of circulating visfatin

AIM

Phenolic compounds naturally contained in extra-virgin olive oil (EVOO) have demonstrated anti-inflammatory and antioxidant properties. The present study aimed at evaluating the effects of a polyphenol-rich extra-virgin olive oil (EVOO) (high-polyphenol EVOO, HP-EVOO) on the metabolic control and the production of specific pro-/anti-inflammatory adipokines in overweight patients with type 2 diabetes mellitus (T2D).

METHODS

Eleven overweight T2D patients not in treatment with insulin were invited to follow their habitual diet for a total of 8 weeks. During the first 4 weeks (wash-out period), they were asked to consume refined olive oil (ROO, polyphenols not detectable) and then to replace ROO with HP-EVOO (25 mL/day, 577 mg of phenolic compounds/kg) for the remaining 4 weeks. Anthropometric parameters, fasting glycaemia, glycated haemoglobin (HbA1c), high-sensitive C-reactive protein, plasma lipid profile, liver function and serum levels of TNF-α, IL-6, adiponectin, visfatin and apelin were assessed at the end of each 4-week period.

RESULTS

HP-EVOO consumption significantly reduced fasting plasma glucose (P = 0.023) and HbA1c (P = 0.039) levels as well as BMI (P = 0.012) and body weight (P = 0.012). HP-EVOO ingestion determined a reduction in serum level of aspartate aminotransferase (AST, P = 0.0056) and alanine aminotransferase (ALT, P = 0.024). Serum visfatin levels strongly decreased after HP-EVOO ingestion (P = 0.0021).

CONCLUSIONS

Daily consumption of polyphenol-rich EVOO might improve metabolic control and circulating inflammatory adipokines profile in overweight T2D patients.

Spread of a carbapenem- and colistin-resistant Acinetobacter baumannii ST2 clonal strain causing outbreaks in two Sicilian hospitals

BACKGROUND

Infections caused by multidrug-resistant (MDR) Acinetobacter baumannii have become an important healthcare-associated problem, particularly in intensive care units (ICUs).

AIM

To investigate the emergence of carbapenem- and colistin-resistant A. baumannii infections in two Sicilian hospitals.

METHODS

From October 2008 to May 2011, a period which included two Italian Nosocomial Infections Surveillance in ICUs network (SPIN-UTI) project surveys, all carbapenem-resistant A. baumannii isolates from the ICUs of two hospitals in Catania, Italy, were prospectively collected. Minimum inhibitory concentrations (MICs) were measured by agar dilution, and phenotypic testing for metallo-β-lactamase (MBL) production was performed. Carbapenem resistance genes and their genetic elements were identified by polymerase chain reaction and sequencing. Genotypic relatedness was assessed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing. Patient-based surveillance was conducted using the SPIN-UTI protocol and previous antibiotic consumption was recorded.

FINDINGS

Twenty-six carbapenem-resistant A. baumannii were identified. Imipenem and meropenem MICs ranged from 4 to >32 mg/L, and 15 isolates exhibited high-level colistin resistance (MICs >32 mg/L). PFGE demonstrated that all isolates belonged to a unique clonal type and were assigned to ST2 of the international clone II. They harboured an intrinsic blaOxA-51-like carbapenemase gene, blaOxA-82, which was flanked upstream by ISAba1.

CONCLUSIONS

The dissemination of clonally related isolates of carbapenem-resistant A. baumannii in two hospitals is described. Simultaneous resistance to colistin in more than half of the isolates is a problem for effective antibiotic treatment. Prior carbapenem and colistin consumption may have acted as triggering factors.

Fasting and post-prandial adipose tissue lipoprotein lipase and hormone-sensitive lipase in obesity and type 2 diabetes

BACKGROUND

Fasting and post-prandial abnormalities of adipose tissue (AT) lipoprotein lipase (LPL) and hormone- sensitive lipase (HSL) activities may have pathophysiological relevance in insulin-resistant conditions.

AIM

The aim of this study was to evaluate activity and gene expression of AT LPL and HSL at fasting and 6 h after meal in two insulin-resistant groups - obese with Type 2 diabetes and obese without diabetes - and in non-diabetic normal-weight controls.

MATERIAL/SUBJECTS AND METHODS

Nine obese subjects with diabetes, 10 with obesity alone, and 9 controls underwent measurements of plasma levels of glucose, insulin, and triglycerides before and after a standard fat-rich meal. Fasting and post-prandial (6 h) LPL and HSL activities and gene expressions were determined in abdominal subcutaneous AT needle biopsies.

RESULTS

The diabetic obese subjects had significantly lower fasting and post-prandial AT heparin-releasable LPL activity than only obese and control subjects (p<0.05) as well as lower mRNA LPL levels. HSL activity was significantly reduced in the 2 groups of obese subjects compared to controls in both fasting condition and 6 h after the meal (p<0.05), while HSL mRNA levels were not different. There were no significant changes between fasting and 6 h after meal measurements in either LPL or HSL activities and gene expressions.

CONCLUSIONS

Lipolytic activities in AT are differently altered in obesity and Type 2 diabetes being HSL alteration associated with both insulin-resistant conditions and LPL with diabetes per se. These abnormalities are similarly observed in the fasting condition and after a fat-rich meal.

Angiotensin blockade and matrix synthesis by glomerular epithelial cells in high glucose: a further experimental insight into the pathophysiology of diabetic nephropathy

AIMS

Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor-1 (AT-1) antagonists are used in the treatment of proteinuria of diabetic nephropathy. One of the major pathogenic events in this condition is represented by the alteration of the extracellular matrix protein synthesis by glomerular epithelial cells.

MATERIALS AND METHODS

We evaluated the effects of the angiotensin converting enzyme inhibitor, Enalaprilat, and the AT-1 receptor antagonist, Losartan, on mRNA fibronectin and laminin synthesis by glomerular epithelial cells, in conditions mimicking hyperglycemia.

RESULTS

In high glucose conditions, Enalaprilat reduced significantly the mRNA expression of fibronectin (p 0.03), but not significantly that of laminin. Losartan addition to high glucose incubated cells reduced (-30%) mRNA expression of fibronectin, and significantly (p 0.05) the mRNA expression of laminin.

CONCLUSIONS

In addition to the known hemodynamic effects, the improvement of renal function in diabetic patients treated with these compounds may also be due to a modulator effect on extracellular matrix content and composition.

The acquisition of an insulin-secreting phenotype by HGF-treated rat pancreatic ductal cells (ARIP) is associated with the development of susceptibility to cytokine-induced apoptosis

The elucidation of mechanisms regulating the regeneration and survival of pancreatic beta cells has fundamental implications in the cell therapy of type 1 diabetes. The present study had the following three aims: 1. to investigate whether pancreatic ductal epithelial cells can be induced to differentiate into insulin-producing cells by exposing them to hepatocyte growth factor (HGF); 2. to characterize some of the molecular events leading to their differentiation toward a beta-cell-like phenotype; 3. to evaluate the susceptibility of newly differentiated insulin-secreting cells to cytokine-induced apoptosis, a mechanism of beta-cell destruction occurring in type 1 diabetes. We demonstrated that HGF-treated rat pancreatic ductal cell line (ARIP) cells acquired the capability to transcribe the insulin gene and translate its counterpart protein. HGF-treated cells also exhibited a glucose-dependent capability to secrete insulin into the cultured medium. Expression analysis of some of the genes regulating pancreatic beta-cell differentiation revealed a time-dependent transcription of neurogenin-3 and Neuro-D in response to HGF. Finally, we determined the susceptibility to proinflammatory cytokine (PTh1)-induced apoptosis by incubating HGF-treated and untreated ARIP cells with a cocktail of interleukin-1 beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). Such treatment induced apoptotic death, as determined by the TUNEL technique, in about 40% of HGF-treated, insulin-secreting ARIP cells, while untreated ARIP cells were resistant to PTh1-induced apoptosis. In conclusion, we showed that HGF promotes the differentiation of ARIP cells into pancreatic beta-cell-like cells, and that the differentiation toward an insulin-secreting phenotype is associated with the appearance of susceptibility to cytokine-induced apoptosis.

Angiotensin-converting enzyme inhibition modulates high-glucose-induced extracellular matrix changes in mouse glomerular epithelial cells

BACKGROUND/AIM

Extracellular matrix alterations are involved in the pathogenesis of diabetic nephropathy. We evaluated the effects of high glucose concentrations and inhibition of angiotensin-converting enzyme on the laminin and fibronectin production by glomerular epithelial cells.

METHODS

Glomerular epithelial cells were cultured in 5 and 30 mmol/l glucose, with and without enalaprilat (0.3 mmol/l). Laminin and fibronectin were measured (35S-methionine, immunoprecipitation), and their mRNA expression was evaluated (RT-PCR).

RESULTS

The laminin concentration was higher in the cells than in the medium, where an increase of its content was observed under high-glucose conditions (p < 0.01). Fibronectin, found only in the medium, was not modified by the high glucose concentration. Following enalaprilat administration, the laminin concentration was decreased under high-glucose conditions, both in the cell and in the medium (p < 0.001), whereas the fibronectin concentration was increased under high-glucose conditions (p < 0.001). The mRNA expression of laminin and fibronectin under high-glucose conditions only slightly increased. Enalaprilat decreased the fibronectin mRNA synthesis dramatically (>50%, p < 0.0001) under high-glucose conditions.

CONCLUSIONS

Enalaprilat normalizes the abnormal, high-glucose-induced concentration of laminin, while it decreases the fibronectin synthesis. The improvement of the renal function in diabetic patients treated with angiotensin-converting enzyme inhibitors may, in part, be due to a modulator effect on extracellular matrix content and composition.

Hormonal regulation of cytokine release by human fetal membranes at term gestation: effects of oxytocin, hydrocortisone and progesterone on tumour necrosis factor-alpha and transforming growth factor-beta 1 output

Inflammatory cytokines can play an important role in the biomolecular processes leading to labour by regulating prostaglandin production in intrauterine tissues. In the setting of intrauterine infection, an increased production of these cytokines by placenta, decidua and fetal membranes occurs and is responsible for the onset and maintenance of preterm labour. However, the factors involved in the control of cytokine release by these tissues in normal pregnancy at term are still largely unknown. We investigated the possibility that the synthesis and release of tumour necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) by human fetal membranes at term gestation is regulated by several hormones potentially involved either in the maintenance of pregnancy or in the parturitional process. In the present study, the effects of hydrocortisone, progesterone and oxytocin on TNF-alpha and TGF-beta1 release by explants of fetal membranes at term gestation were evaluated. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to assess the effect of the above hormones on mRNA expression; TNF-alpha and TGF-beta1 release in culture medium was quantitifed by ELISA assays. Results show that both tissue mRNA expression for TNF-alpha and TNF-alpha release in culture medium were significantly increased by oxytocin, but not by hydrocortisone and progesterone. On the contrary, all the hormones tested increased both tissue TGF-beta1 mRNA expression and release in culture medium. These findings suggest that TNF-alpha and TGF-beta1 production by human fetal membranes in uncomplicated pregnancy at term is selectively modulated by oxytocin, hydrocortisone and progesterone.

Th2 cytokines have a partial, direct protective effect on the function and survival of isolated human islets exposed to combined proinflammatory and Th1 cytokines

Studies in rodents have suggested that Th2 and Th3 cytokines can be effective in reducing proinflammatory and Th1 cytokine-induced islet damage. Whether this is the case with human islets and might be due to a direct action of Th2 and Th3 cytokines is not known. In the present study, we evaluated whether Th2 (500 U/ml IL-4 plus 100 U/ml IL-10) or Th3 (5 ng/ml TGF-1beta) cytokines may prevent the derangements induced on isolated human islets by prolonged (12 or 72 h) exposure to combined proinflammatory (50 U/ml IL-1beta, 1000 U/ml TNF alpha) and Th1 (1000 U/ml interferon gamma) cytokines. Compared with control islets, cells preincubated for 12 or 72 h with proinflammatory and Th1 cytokines showed a significant decrease of glucose-stimulated insulin secretion and a significant increase of nitrites production. The addition of IL-4 plus IL-10 or TGF-1beta in the medium prevented these cytostatic effects in the 12-h incubation experiments, but not after the 72-h exposure period. IL-1beta, interferon gamma, and TNF alpha caused no major change in either islet cell survival or Bcl-2 and Bax mRNA expression after a 12-h incubation; however, a marked increase in the amount of dead cells, with a major decrease of Bcl-2 mRNA expression, was observed after 72 h. The presence of Th2, but not of Th3, cytokines significantly reduced beta-cell death, without any major effect on Bcl-2 and Bax mRNA expression. These results suggest that Th2 and (at lower extent) Th3 cytokines may have a partial, direct protective effect on isolated human islets exposed to the cytostatic and cytotoxic action of proinflammatory and Th1 cytokines.

Bovine islets are less susceptible than human islets to damage by human cytokines

BACKGROUND

The potential benefits of islet xenografting in type 1 diabetes include the intriguing, but still unanswered, possibility that the grafted xenoislets may be less subjected to human autoimmune attack. Cytokines may play a major role in the pathogenesis of autoimmune diabetes by causing impairment of insulin release and pancreatic islet cell toxicity.

METHODS

We compared insulin secretion, islet cell death and survival, inducible nitric oxide synthase (iNOS) mRNA expression, nitrite production, and Bcl-2 and Bax mRNA expression in isolated human and large mammal (bovine) islets exposed to 50 U/ml recombinant human interleukin-1, 1,000 U/ml recombinant human tumor necrosis factor-alpha and 1,000 U/ml recombinant human interferon-gamma.

RESULTS

After 24-hr exposure, a marked decrease of glucose-stimulated insulin secretion was observed with human, but not with bovine islets. After 48-hr exposure, human, but not bovine, pancreatic islets showed a significantly higher percentage of apoptotic cells compared to controls. Treatment of human islets with human cytokines induced up-regulation of iNOS mRNA, increased levels of nitrites, and down-regulation of Bcl-2 mRNA, with unchanged levels of Bax mRNA. These parameters were not affected by cytokines in bovine islets.

CONCLUSIONS

Bovine islets are less susceptible than human islets to the effects of human cytokines, which may be a potential advantage of xenotransplantation.

Effects of prolonged exposure to pancreatic glucagon on the function, antigenicity and survival of isolated human islets

BACKGROUND

Certain clinical conditions are associated with inappropriately high levels of circulating glucagon. To date, little information is available about the direct effects of prolonged exposure of human islet cells to pancreatic glucagon. In the present study we evaluated the function, antigenicity and survival of human islets exposed for 24 h to human pancreatic glucagon.

METHODS

We prepared human islets of Langerhans by collagenase digestion and density-gradient purification, incubated them for 24 h with 44 or 430 pmol/l pancreatic glucagon at physiological (5.5 mmol/l) glucose level, and evaluated their insulin release function, which was then compared with that obtained from islets kept at high (11.1 mmol/l) glucose concentration. In addition, aliquots of the islets were evaluated to assess their chemotactic properties towards human monocyte-macrophage cells, and their potency to induce cytokine release from human lymphocytes. Finally, survival of the islet cells cultured under varying conditions was evaluated, and an assessment was performed of mRNA expression of Bcl-2 and Bax proteins.

RESULTS

The insulin secretion results demonstrated that, compared to the control islets, the islets previously exposed to either 44 or 430 pmol/l glucagon exhibited changes in insulin release in response to glucose, consisting of augmented secretion at low glucose challenge, and no further significant increase at high glucose stimulation, similar to the effects observed with islets pre-cultured with high glucose. These effects were reversible, as documented by the recovery of normal islet sensitivity to glucose after an additional 24-h culture in medium lacking glucagon. Compared to control islets, the culture medium from islets pre-cultured with high glucagon or high glucose showed an increased chemotactic potency towards human monocyte-macrophage cells. In addition, human lymphocytes released a greater amount of tumour necrosis factor alpha when co-cultured with the islets pre-exposed to high glucagon or high glucose, whereas no significant difference was observed (in comparison with control islets) as regards the release of gamma-interferon, interleukin-2 and interleukin-10. The TUNEL technique and RT-PCR showed, respectively, no major difference in cell survival and expression of mRNA encoding for Bcl-2 and Bax protein between control islets and islets kept for 24 h in the presence of high glucagon or high glucose.

CONCLUSIONS

Our results show that in vitro exposure of human islets to pancreatic glucagon for 24 h causes changes in the function and antigenicity of isolated human islets that are similar to the changes observed after pre-culture with increased glucose levels. Under our experimental conditions, these changes were not accompanied by any evidence of cytotoxicity.

Nitric oxide synthases in normal and benign hyperplastic human prostate: immunohistochemistry and molecular biology

The expression of nitric oxide synthase (NOS) isoforms has been investigated in normal (three subjects) and benign hyperplastic prostate (ten patients) by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR). The inducible NOS (iNOS or NOS-2) is not detected in normal prostate, while it is expressed in the prostate of all benign prostatic hyperplasia (BPH) patients, even in the absence of prostatitis or systemic signs of an inflammatory condition. This suggests that sex hormones may be involved in iNOS induction and that there may be a role for NO in the pathogenesis of BPH. Constitutive NOSs (nNOS and eNOS) are expressed in both normal and hyperplastic prostate and are co-expressed in epithelial cells. eNOS, however, is present mainly in the basal layer cells; nNOS seems abundantly expressed in the more superficial cells of the affected prostate. This indicates that the switching between the two constitutive isoforms may be part of the usual process of cell differentiation from the basal to the secretory layer of the epithelium.

Expression of p53 and retinoblastoma gene in high-grade nodal peripheral T-cell lymphomas: immunohistochemical and molecular findings suggesting different pathogenetic pathways and possible clinical implications

The expression of p53 and the retinoblastoma gene has been investigated by immunohistochemical and molecular analysis in 45 cases of nodal peripheral T-cell lymphoma with high-grade histology. Most cases (73.3 per cent) were primary nodal lymphomas without any extra-nodal site involvement. Most of them (75.6 per cent) were histologically classified as pleomorphic, small, medium, and large cell type. Immunohistochemistry detected p53 in nine cases (20 per cent). In each of these cases, the polymerase chain reaction (PCR)/heteroduplex analysis did not show the presence of mutations, this finding being consistent with an alteration of the p53 functional pathway, in the presence of a wild-type protein. The retinoblastoma gene product was detected by immunohistochemistry in 35 cases (77.8 per cent) and not detected in ten cases (22.2 per cent). In the latter cases, the reverse transcription (RT)-PCR analysis showed the presence of a specific retinoblastoma gene transcript in six cases and was negative in the remaining four cases. The immunohistochemical and molecular findings seem to be consistent with abnormalities of retinoblastoma gene expression at either the transcriptional or the post-transcriptional level. Since all nine p53-positive cases by immunohistochemical analysis were also retinoblastoma gene product-positive, and all ten retinoblastoma gene product-negative cases were also p53-negative, two different and mutually exclusive pathways of possible pathogenetic significance may be suggested, the former involving abnormalities of the functional pathway of p53 in the absence of mutations and the latter abnormalities of retinoblastoma gene expression at the transcriptional and/or post-transcriptional level. Finally, the clinico-pathological correlations showed that p53 immunohistochemical expression is significantly associated with a poorer response to intensive chemotherapy.

Involvement of bcl-2 and bax gene expression in apoptosis and differentiation of the non-tumorigenic murine hematopoietic cell line, 32DC13(G)

32DCl3(G) is an interleukin-3 (IL-3) dependent, non-tumorigenic murine hematopoietic cell line which undergoes terminal differentiation into granulocytes when exposed to granulocyte-colony stimulating factor (G-CSF). This line therefore offers a convenient system to study the expression of genes involved in apoptosis and differentiation. In our experiments we have acquired evidence that during the differentiation pathway, likewise in apoptosis induced by IL-3 deprivation, detectable levels of bax mRNA appear, while bcl-2 expression decreases. These events are under the control of the p53 tumor-suppressor gene. In these cells, an overexpression of exogenous wild-type p53 leads to a decrease in bcl-2 mRNA and to the appearance of box mRNA, which instead is absent in the parental cells growing in IL-3 conditioned medium. Furthermore, results from experiments on p53 transfected cells demonstrate that excess wild-type p53 activity, on its own, fails to elicit apoptosis as long as IL-3 is present and does not induce differentiation if G-CSF is not added to the culture medium. We conclude that in apoptosis and differentiation of 32DCl3(G) the alterate ratio of bcl-2 and box gene expression, modulated by p53, is an early event dependent on IL-3 withdrawal and that the appearance of bax and the decrease of bcl-2 expression are necessary, but not sufficient for the acquisition of a completely mature granulocytic phenotype.

"Normal" control subjects are hard to find: a model for centralized recruitment

A central program for recruiting "normal" control subjects is examined by considering the yield of subjects who meet criteria for "healthy" as defined by their personal and family histories of mental disorders. Of the 267 applicants, 30.3% have no lifetime diagnoses, 41.2% are currently healthy with a history of mental illness, and 27.7% are currently mentally ill. Only 16.1% met Research Diagnostic Criteria for "never mentally ill" and reported no family history of mental disorders. Benefits of a central recruitment program for studies of mental disorders include increased information on a large subject pool and decreased volunteer bias.