Interplay of spermatogonial subpopulations during initial stages of spermatogenesis in adult primates

The spermatogonial compartment maintains spermatogenesis throughout the reproductive lifespan. Single-cell RNA sequencing (scRNA-seq) has revealed the presence of several spermatogonial clusters characterized by specific molecular signatures. However, it is unknown whether the presence of such clusters can be confirmed in terms of protein expression and whether protein expression in the subsets overlaps. To investigate this, we analyzed the expression profile of spermatogonial markers during the seminiferous epithelial cycle in cynomolgus monkeys and compared the results with human data. We found that in cynomolgus monkeys, as in humans, undifferentiated spermatogonia are largely quiescent, and the few engaged in the cell cycle were immunoreactive to GFRA1 antibodies. Moreover, we showed that PIWIL4+ spermatogonia, considered the most primitive undifferentiated spermatogonia in scRNA-seq studies, are quiescent in primates. We also described a novel subset of early differentiating spermatogonia, detectable from stage III to stage VII of the seminiferous epithelial cycle, that were transitioning from undifferentiated to differentiating spermatogonia, suggesting that the first generation of differentiating spermatogonia arises early during the epithelial cycle. Our study makes key advances in the current understanding of male germline premeiotic expansion in primates.

Age-related changes in human Leydig cell status

STUDY QUESTION

What are the consequences of ageing on human Leydig cell number and hormonal function?

SUMMARY ANSWER

Leydig cell number significantly decreases in parallel with INSL3 expression and Sertoli cell number in aged men, yet the in vitro Leydig cell androgenic potential does not appear to be compromised by advancing age.

WHAT IS KNOWN ALREADY

There is extensive evidence that ageing is accompanied by decline in serum testosterone levels, a general involution of testis morphology and reduced spermatogenic function. A few studies have previously addressed single features of the human aged testis phenotype one at a time, but mostly in tissue from patients with prostate cancer.

STUDY DESIGN, SIZE, DURATION

This comprehensive study examined testis morphology, Leydig cell and Sertoli cell number, steroidogenic enzyme expression, INSL3 expression and androgen secretion by testicular fragments in vitro. The majority of these endpoints were concomitantly evaluated in the same individuals that all displayed complete spermatogenesis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Testis biopsies were obtained from 15 heart beating organ donors (age range: 19-85 years) and 24 patients (age range: 19-45 years) with complete spermatogenesis. Leydig cells and Sertoli cells were counted following identification by immunohistochemical staining of specific cell markers. Gene expression analysis of INSL3 and steroidogenic enzymes was carried out by qRT-PCR. Secretion of 17-OH-progesterone, dehydroepiandrosterone, androstenedione and testosterone by in vitro cultured testis fragments was measured by LC-MS/MS. All endpoints were analysed in relation to age.

MAIN RESULTS AND THE ROLE OF CHANCE

Increasing age was negatively associated with Leydig cell number (R = -0.49; P < 0.01) and concomitantly with the Sertoli cell population size (R= -0.55; P < 0.001). A positive correlation (R = 0.57; P < 0.001) between Sertoli cell and Leydig cell numbers was detected at all ages, indicating that somatic cell attrition is a relevant cellular manifestation of human testis status during ageing. INSL3 mRNA expression (R= -0.52; P < 0.05) changed in parallel with Leydig cell number and age. Importantly, steroidogenic capacity of Leydig cells in cultured testis tissue fragments from young and old donors did not differ. Consistently, age did not influence the mRNA expression of steroidogenic enzymes. The described changes in Leydig cell phenotype with ageing are strengthened by the fact that the different age-related effects were mostly evaluated in tissue from the same men.

LIMITATIONS, REASONS FOR CAUTION

In vitro androgen production analysis could not be correlated with in vivo hormone values of the organ donors. In addition, the number of samples was relatively small and there was scarce information about the concomitant presence of potential confounding variables.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides a novel insight into the effects of ageing on human Leydig cell status. The correlation between Leydig cell number and Sertoli cell number at any age implies a connection between these two cell types, which may be of particular relevance in understanding male reproductive disorders in the elderly. However aged Leydig cells do not lose their in vitro ability to produce androgens. Our data have implications in the understanding of the physiological role and regulation of intratesticular sex steroid levels during the complex process of ageing in humans.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by grants from Prin 2010 and 2017. The authors have no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Spermatogonial kinetics in humans

The human spermatogonial compartment is essential for daily production of millions of sperm. Despite this crucial role, the molecular signature, kinetic behavior and regulation of human spermatogonia are poorly understood. Using human testis biopsies with normal spermatogenesis and by studying marker protein expression, we have identified for the first time different subpopulations of spermatogonia. MAGE-A4 marks all spermatogonia, KIT marks all B spermatogonia and UCLH1 all Apale-dark (Ap-d) spermatogonia. We suggest that at the start of the spermatogenic lineage there are Ap-d spermatogonia that are GFRA1^High, likely including the spermatogonial stem cells. Next, UTF1 becomes expressed, cells become quiescent and GFRA1 expression decreases. Finally, GFRA1 expression is lost and subsequently cells differentiate into B spermatogonia, losing UTF1 and acquiring KIT expression. Strikingly, most human Ap-d spermatogonia are out of the cell cycle and even differentiating type B spermatogonial proliferation is restricted. A novel scheme for human spermatogonial development is proposed that will facilitate further research in this field, the understanding of cases of infertility and the development of methods to increase sperm output.

Current practice of brain death determination and use of confirmatory tests in an Italian University hospital: a report of 66 cases

BACKGROUND

Time to final brain death (BD) determination is fundamental to rapidly identify donors without organ deterioration. Guidelines for BD determination are different from country to country and, through years, they have been subjected to several revisions, to simplify the procedure. The aim of this study was to describe a one-year experience according to the latest Italian Guidelines for BD in our University hospital and to focus on timing of final BD declaration according to the ancillary tests executed.

METHODS

Sixty-six consecutive inpatients with BD diagnosis were enrolled. Etiological factors, ancillary tests and timing to final declaration were analyzed.

RESULTS

Electroencephalogram (EEG) could be performed without artifacts in all the patients. Time to BD procedure starting depended on whether the demonstration of cerebral circulatory arrest was required, being shorter with EEG only (40±17 min), longer with cerebral blood flow evaluation (175±95 min), minimal with transcranial Doppler (83±32 min), maximal with angiography (165±20 min). None of the patients who initiated BD procedure were found to recover cerebral or brainstem function at the second observation.

CONCLUSIONS

In Italy, the same guidelines ensure the same approach in every hospital, with multi-specialist cooperation. The EEG is mandatory and prompt recognition of the first, flat EEG is fundamental to reduce time to the final procedure. A multimodal neurophysiological approach with trained specialists, neurosonologists and monitoring devices in intensive care units may represents a valid help to further reduce time for BD diagnosis.

Rescue treatment for noninvasive ventilation failure due to interface intolerance with remifentanil analgosedation: a pilot study

PURPOSE

To assess the feasibility of remifentanil-based sedation in hypoxemic acute respiratory failure (HARF) patients refusing to continue noninvasive ventilation (NPPV) for intolerance to two different interfaces-helmet and total face mask.

DESIGN AND SETTING

Prospective uncontrolled clinical investigation in a 14-bed ICU of an university hospital in Italy.

PATIENTS

Thirty-six patients with persistent severe HARF who complained of discomfort and asked for interruption of NPPV session.

INTERVENTION

Patients started sedation with remifentanil (0.025 μg kg(-1) min(-1)) and the infusion rate was increased by 0.01 μg kg(-1) min(-1) every minute to a maximum of 0.12 μg kg(-1) min(-1) to obtain patient comfort.

MEASUREMENTS AND RESULTS

Twenty-two out of 36 patients (61%) with median (IQR) SAPS II score of 32 (30, 38) continued the NPPV treatment after the introduction of remifentanil infusion. In this success group, median (IQR) respiratory rate decreased from 34 (31, 37) to 24 (20, 26) min(-1) (p < 0.0001) and PaO(2)/FiO(2) ratio increased from 156 (144, 176) to 270 (210, 300) mmHg (p < 0.0001) after 1 h of NPPV with remifentanil-analgosedation either with helmet or total face mask. Fourteen patients failed to continue the noninvasive treatment and were intubated after a mean of 2.5 ± 2.3 h; they showed a respiratory rate decrease from 35 (30, 38) to 27 (25, 35) min(-1) (p = 0.02) and an inability to increase the PaO(2)/FiO(2) ratio above 180 mmHg. The ICU mortality in the failure group patients was 50 versus 14% in the NPPV success group (p < 0.05). The mean remifentanil dose administered was 0.07 ± 0.03 μg kg(-1) min(-1).

CONCLUSION

This clinical study suggests that a remifentanil-based sedation protocol can decrease the rate of failure in patients with intolerance to NPPV.

Transcranial Doppler for brain death in infants: the role of the fontanelles

OBJECTIVE

Transcranial Doppler (TCD) is a sensitive technique for circulatory arrest diagnosis in brain death when patterns such as reverberant flow and short systolic spikes are observed. In infants, the nonossified fontanelles compensate for intracranial hypertension. We describe TCD patterns in infants with brain death, different from adults, with the hemodynamic modifications induced by anterior fontanelle compression.

METHOD

TCD was performed in 2 infants with diagnosed brain death admitted to the neonatal intensive care unit.

RESULTS

TCD showed a large peak 'reverberant' flow, with a high peak systolic velocity and a consistent retrograde component, away from the brain. Compression of the anterior fontanelle induced, at first, a reduction in systolic flow with the subsequent appearance of the characteristic short systolic spikes. Upon compression removal, a brief increase in the systolic flow was observed before the prompt reappearance of the reverberant flow.

CONCLUSION

TCD for brain death diagnosis should be done cautiously in infants. In these cases, reverberating flow may be indicative of circulatory arrest even if with a large peak and with a high peak systolic velocity. Heavy fontanelle compression may reproduce the classical adult TCD patterns of brain death, thus supporting the diagnosis of cerebral circulatory arrest.

Noninvasive Ventilation by Helmet or Face Mask in Immunocompromised Patients

OBJECTIVE

To compare the efficacy of noninvasive positive pressure ventilation (NPPV) by helmet and face mask in immunocompromised patients with hypoxemic acute respiratory failure (ARF).

DESIGN

Case-control study.

SETTING

The general ICU of a university hospital.

PATIENTS

Nineteen immunocompromised patients (hematologic malignancies [n = 8], solid-organ recipients [n = 8], AIDS [n = 3]) with hypoxemic ARF, fever, and lung infiltrates were treated with NPPV delivered by a helmet. Nineteen immunocompromised patients matched for diagnosis, age, simplified acute physiology score II, and Pao(2)/fraction of inspired oxygen (Fio(2)) receiving NPPV through a facial mask served as case-control subjects.

RESULTS

The use of NPPV delivered via helmet was as effective as NPPV delivered via face mask in avoiding endotracheal intubations (intubation rate, 37% vs 47%, respectively; p = 0.37) and improving gas exchange; 14 patients (74%) in the helmet group showed a sustained improvement in Pao(2)/Fio(2) ratio (ability to increase Pao(2)/Fio(2) ratio > 200, or an increase > 100 from the baseline) in comparison with 7 patients (34%) in the mask group (p = 0.02), whose Pao(2)/Fio(2) at treatment discontinuation was higher (p = 0.02) and had fewer complications related to NPPV (ie, skin necrosis, p = 0.01). Moreover, the patients receiving ventilation via helmet required significantly less NPPV discontinuations in the first 24 h of application (p < 0.001) than patients receiving ventilation via face mask.

CONCLUSIONS

The helmet may represent a valid alternative to a face mask in immunocompromised patients with lung infiltrates and hypoxemic ARF, increasing the patient's tolerance (ie, the number of hours of continuous NPPV use without interruptions) and decreasing the rate of complications directly related to the administration of NPPV.

A comparative evaluation of thermodilution and partial CO2 rebreathing techniques for cardiac output assessment in critically ill patients during assisted ventilation

OBJECTIVE

To evaluate the reliability and clinical value of partial noninvasive CO2 (NICO2) rebreathing technique for measuring cardiac output compared with standard thermodilution in a group of intensive care nonpostoperative patients.

DESIGN AND SETTING

Clinical investigation in a university hospital ICU.

PATIENTS

Twelve mechanically ventilated patients with high (n=6) and low (n=6) pulmonary shunt fractions.

MEASUREMENTS AND RESULTS

Thirty-six paired measurements of cardiac output were carried out with NICO2 and thermodilution in patients ventilated in pressure-support mode and sedated with a sufentanil continuous infusion to obtain a Ramsay score value of 2. The mean cardiac output was: thermodilution 7.27+/-2.42 l/min; NICO2 6.10+/-1.66 l/min; r2 was 0.62 and bias -1.2 l/min+/-1.5. Mean values of cardiac output were similar in the low shunt group (Qs/Qt < 20), with r2=0.90 and a bias of 0.01 l/min+/-0.4; conversely, in the high pulmonary shunt group (Qs/Q > 35%) the mean was 9.32+/-1.23 l/min with thermodilution and a mean NICO2CO value was 6.97+/-1.53 l/min, with r2 of 0.38 and a bias of -2.3 l+/-1.2 min.

CONCLUSIONS

The partial CO2 rebreathing technique is reliable in measuring cardiac output in nonpostoperative critically ill patients affected by diseases causing low levels of pulmonary shunt, but underestimates it in patients with shunt higher than 35%.

Noninvasive vs. conventional mechanical ventilation in patients with chronic obstructive pulmonary disease after failure of medical treatment in the ward: a randomized trial

OBJECTIVE

We conducted a randomized prospective study comparing noninvasive positive pressure ventilation (NPPV) with conventional mechanical ventilation via endotracheal intubation (ETI) in a group of patients with chronic obstructive pulmonary disease who failed standard medical treatment in the emergency ward after initial improvement and met predetermined criteria for ventilatory support.

DESIGN AND SETTING

Prospective randomized study in a university hospital 13-bed general ICU.

PATIENTS

Forty-nine patients were randomly assigned to receive NPPV (n=23) or conventional ventilation (n=26).

RESULTS

both NPPV and conventional ventilation significantly improved gas exchanges. The two groups had similar length of ICU stay, number of days on mechanical ventilation, overall complications, ICU mortality, and hospital mortality. In the NPPV group 11 (48%) patients avoided intubation, survived, and had a shorter duration of ICU stay than intubated patients. One year following hospital discharge the NPPV group had fewer patients readmitted to the hospital (65% vs. 100%) or requiring de novo permanent oxygen supplementation (0% vs. 36%).

CONCLUSIONS

The use of NPPV in patients with chronic obstructive pulmonary disease and acute respiratory failure requiring ventilatory support after failure of medical treatment avoided ETI in 48% of the patients, had the same ICU mortality as conventional treatment and, at 1-year follow-up was associated with fewer patients readmitted to the hospital or requiring for long-term oxygen supplementation. An editorial regarding this article can be found in the same issue (http://dx.doi.org/10.1007/s00134-002-1503-3).

[Microbiological surveillance in an intensive care unit of a large Roman hospital]

Infection surveillance in ICU is fundamental to monitor endemic rates, to identify outbreaks on-time in order to activate control procedures implementing a correct empirical antibiotic treatment. The data collection surveillance software CIN-20002 was established in the Teaching Hospital Umberto I ICU to monitor the following site-specific infection rates: urinary tract infections (UTI), pneumonia (PNE), blood stream infections (BSI), surgical site infections (SSI). According to CDC definitions all patients developing infection 48 hours or more after ward admission were included. Furthermore risk factors (i.e. age, sex, SAPS II), invasive procedures (i.e. endotracheal intubation, vascular and urinary catheterisation), microbiological isolates and their antibiotic susceptibility were screened. Overall 279 patients (183 men and 96 women) were admitted; age 54,8 20,3 years (mean), SAPS II 44,4 17,1 (mean) and average ward stay 13,3 17,8 days. Results showed a total of 121 infection episodes (56 PNE, 51 BSI, 10 UTI e 4 SSI) in 80 patients (28,7%). Standardized infection rates associated to invasive procedures were: Urinary catheter-associated UTI rate (2.9/1000), Ventilator-associated PNE rate (20.4/1000), Vascular catheter-associated BSI rate (19.1/1000). Among the infected patients the most common microrganisms isolated were P. aeruginosa (31,8%), MRSA (14,8%), A. baumanni (12,5%) e S. maltophilia (8,5%). Considering site-specific infections: PNE (P. aeruginosa 38,3% and MRSA 18,1%), BSI (MR CNS 21,9% and P. aeruginosa 17,2%), UTI (P. aeruginosa 70,0%). The surveillance software CIN-2000 proved to be very accurate, usefull and easy to use. The results showed a high incidence of infections associated to invasive procedures and the presence of multiresistant bacteria

Lipid peroxidation, circulating cytokine and endothelin 1 levels in healthy volunteers undergoing hyperbaric oxygenation

BACKGROUND

The aim of the present study was to evaluate the effects of hyperbaric oxygenation on lipid peroxidation, on the release of circulating cytokines (TNFa, IL6, IL1b) and endothelin-1 (ET1).

METHODS

EXPERIMENTAL DESIGN

single arm, prospective study.

SETTING

ICU hyperbaric division of a University Hospital.

PATIENTS

fifteen healthy volunteers (10 male and 5 female, mean age 32+/-7 years) studied during hyperbaric oxygenation divided at random into two groups: group A (7 subjects) and group B (8 subjects).

INTERVENTIONS

Both groups were consecutively pressurized at 2 atmospheres (2 atm abs) and 2.8 atm abs, with a constant descending rate of 1 m/min; in accordance with the experimental design, group A breathed pure oxygen continuously through facial masks and group B breathed chamber air during pressurization.

MEASURES

Twenty millilitres of blood were drawn from all individuals at the following times: 1) basal, before HBO; 2) after 10 min at 2 atm abs; 3) after 10 min at 2.8 atm abs; 4) 30 min after the end of HBO. In all collected samples thiobarbituric reacting substances were evaluated, using the spectrophotometric technique, IL1 TNF and IL6 serum levels by ELISA and endothelin 1 plasma levels by radioimmunoassay.

RESULTS

In both groups, TBARS levels showed a twofold increase (p<0.05) in relation to the baseline, during and after hyperbaric oxygenation. Serum IL6 and IL1b values did not significantly change over the study in any of the volunteers. TNFa amounts significantly increased (p<0.05) during HBO, at 2 atm abs and 2.8 atm abs in both groups, with almost twofold increments. ET1 plasma values increased (p<0.05) in all volunteers during and after HBO: at 2 atm abs (range 7 to 24 pg/ml), 2.8 atm abs (range 7 to 19 pg/ml) and 30 min after (range 8 to 17 pg/ml) in relation to baseline (range 4 to 12 pg/ml). All the studied compounds had a similar trend in the two groups.

CONCLUSIONS

Hyperbaric oxygenation in healthy volunteers can induce not only lipid peroxidation, but also liberation of compounds such as TNFa and endothelins, no matter whether pure oxygen is breathed or not. These results suggest that the phenomenon behind this release might be leukocyte activation as induced by HBO. The possible role of ET1 in determining vasoconstriction occurring during HBO is also suggested.

Non invasive ventilation in the treatment of FUdr-induced lesional pulmonary oedema

2-deoxy-5-fluorouridine, also known as floxuridine (FUdr) is a fluoropyridine antimetabolite, used in the treatment of metastatic renal cell carcinoma. We report the first case of lesional pulmonary oedema developed after receiving Fudr, recently treated in our unit. The patient refused endotracheal intubation, and was successfully treated associating noninvasive ventilation (NIV) with full-face mask to steroid treatment. The authors conclude that mechanical ventilation via face-mask can be an effective, comfortable, dignified method of support for patients with end-stage disease and acute respiratory failure.

[Assessment of lipid peroxidation in hyperbaric oxygen therapy: protective role of N-acetylcysteine]

OBJECTIVE

To verify and quantify lipidic peroxidation by means of tiobarbituric-acid reactive substance (TBARS) dosage in patients treated daily with HBO. To verify if a potentiated glutathione enzymatic system, with N-acetylcisteine (NAC) treatment, may determine higher HBO tolerance and reduced lipidic peroxidation.

DESIGN

Randomised study on patients treated with 20 HBO 2.2 ATA (90' oxygen) sessions.

SETTING

Hyperbaric Medical Centre.

PATIENTS

Seventeen patients divided, at random, into two groups; group A: 10 patients treated with only HBO; group B: 7 patients treated with NAC antioxidant therapy (Fluimucil, Zambon Group, Italy) 1800 mg/day in addition to HBO.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

TBARS on blood sample at T0 (basal) T1 (at the end of the 1st HBO session) T2 (at the beginning of the 20th HBO session) T3 (at the end of the 20th). The group A TBARS analysis at the different study time has shown significant data (p < 0.01) as the difference between TBARS values of the two groups at T2 (p < 0.01).

CONCLUSIONS

HBO induces a lipidic peroxidation even if the therapeutical protocol cannot determine lung or cerebral oxygen toxicity symptoms. The NAC administration, during HBO treatment, determines a protection against the HBO radicalic stress.