Antiretroviral protease inhibitors induce features of cellular senescence that are reversible upon drug removal

Antiretroviral drugs have dramatically improved the prognosis of HIV-infected patients, with strikingly reduced morbidity and mortality. However, long-term use can be associated with signs of premature aging. Highly active antiretroviral therapy generally comprises two nucleoside reverse transcriptase inhibitors (NRTIs), with one of three additional antiretroviral drug classes, including protease inhibitors (PIs). One commonality between mitochondrial dysfunction (induced by NRTIs) and defects in lamin A (induced by PIs) is they can cause or accelerate cellular senescence, a state of essentially irreversible growth arrest, and the secretion of many bioactive molecules collectively known as the senescence-associated secretory phenotype (SASP). We hypothesized that senescent cells increase following treatment with certain HIV therapies. We compared the effects of two distinct HIV PIs: ritonavir-boosted atazanavir (ATV/r) and ritonavir-boosted darunavir (DRN/r), used in combination treatments for HIV infection. Upon ATV/r, but not DRN/r, treatment, cells arrested growth, displayed multiple features of senescence, and expressed significantly upregulated levels of many SASP factors. Furthermore, mice receiving sustained ATV/r treatment showed an increase in senescent cells and age-related decline in physiological function. However, removing treatment reversed the features of senescence observed in vivo and cell culture. Given how these features disappeared with drug removal, certain features of senescence may not be prognostic as defined by an irreversible growth arrest. Importantly, for patients that are treated or have been treated with ATV/r, our data suggest that switching to another PI that does not promote premature aging conditions (DRN/r) may improve the associated age-related complications.

Deficiency in the DNA repair protein ERCC1 triggers a link between senescence and apoptosis in human fibroblasts and mouse skin

ERCC1 (excision repair cross complementing‐group 1) is a mammalian endonuclease that incises the damaged strand of DNA during nucleotide excision repair and interstrand cross‐link repair. Ercc1^−/Δ mice, carrying one null and one hypomorphic Ercc1 allele, have been widely used to study aging due to accelerated aging phenotypes in numerous organs and their shortened lifespan. Ercc1^−/Δ mice display combined features of human progeroid and cancer‐prone syndromes. Although several studies report cellular senescence and apoptosis associated with the premature aging of Ercc1^−/Δ mice, the link between these two processes and their physiological relevance in the phenotypes of Ercc1^−/Δ mice are incompletely understood. Here, we show that ERCC1 depletion, both in cultured human fibroblasts and the skin of Ercc1^−/Δ mice, initially induces cellular senescence and, importantly, increased expression of several SASP (senescence‐associated secretory phenotype) factors. Cellular senescence induced by ERCC1 deficiency was dependent on activity of the p53 tumor‐suppressor protein. In turn, TNFα secreted by senescent cells induced apoptosis, not only in neighboring ERCC1‐deficient nonsenescent cells, but also cell autonomously in the senescent cells themselves. In addition, expression of the stem cell markers p63 and Lgr6 was significantly decreased in Ercc1^−/Δ mouse skin, where the apoptotic cells are localized, compared to age‐matched wild‐type skin, possibly due to the apoptosis of stem cells. These data suggest that ERCC1‐depleted cells become susceptible to apoptosis via TNFα secreted from neighboring senescent cells. We speculate that parts of the premature aging phenotypes and shortened health‐ or lifespan may be due to stem cell depletion through apoptosis promoted by senescent cells.

Osteosclerotic bone dysplasia in siblings with a Fam20C mutation

Raine syndrome is an autosomal recessive disorder caused by mutations in the FAM20C gene. FAM20C codes for the human homolog of DMP4, a dentin matrix protein highly expressed in odontoblasts and moderately in bone. DMP4 is probably playing a role in the mineralization process. Since the first case reported in 1989 by Raine et al. 21 cases have been published delineating a phenotype which associates dysmorphic features, cerebral calcifications, choanal atresia or stenosis and thoracic/pulmonary hypoplasia. Kan and Kozlowski suggested the name of Raine syndrome to describe this new lethal osteosclerotic bone dysplasia. All the cases described were lethal during the neonatal period except for the last two reported patients aged 8 and 11 years who presented severe mental retardation. Here we describe two sisters, with an attenuated phenotype of Raine syndrome, who present an unexpectedly normal psychomotor development at ages 4 and 1, respectively. Identification of a homozygous mutation in the FAM20C gene confirmed the Raine syndrome diagnosis, thus contributing to the expansion of the Raine syndrome phenotype. This case report also prompted us to revisit the FAM20 gene classification and allowed us to highlight the ancestral status of Fam20C.

Use of digital camera imaging of eye fundus for telemedicine in children suspected of abusive head injury

AIM

Pilot study of the role of RetCam imaging for telemedicine in lieu of availability of ophthalmologist examination for cases of suspected abusive head injury.

DESIGN

Cross-sectional observational study.

PARTICIPANTS

21 children admitted in the paediatric units of the University Hospital of Strasbourg (France) with suspicion of abusive head trauma were included.

METHODS

Children were examined by standard ophthalmoscopy. Photographs were taken using the RetCam-120 Digital Retinal Camera. Eye fundus images were stored and remotely read by an ophthalmologist. Patients also had radiographic skeletal series to look for bone fractures, and CT scan and/or MRI of the head to look for intracranial haemorrhages.

MAIN OUTCOME MEASURES

The absence or presence of retinal haemorrhages was assessed by both methods. Feasability, sensitivity and specificity of the digital camera procedure were determined.

RESULTS

85.7% of the children presented cerebral bleeding, and 14 out of the 21 (66.7%) had retinal haemorrhages on ophthalmoscopy. The digital camera detected the retinal abnormalities in all cases. One false-positive case was also reported. The sensitivity of the digital camera detection method was 100% with a specificity of 85.7%. 14 patients were eventually diagnosed as suffering from abusive trauma. RetCam helped establishing the diagnosis of abuse in 92.8% of these cases.

CONCLUSIONS

Digital photography compared with ophthalmoscopy has a good sensitivity and specificity in detecting retinal haemorrhages. Remote reading of RetCam-120 photographs could be a promising strategy in detecting children with abusive head trauma.

[Ondine's Curse and rare oculomotor abnormalities: a case report]

Ondine's Curse or congenital central hypoventilation syndrome (CCHS) is a neurocristopathy (failure of migration or differentiation of neural crest-derived precursor cells) and is characterized by hypoventilation or apnea, which is most pronounced during sleep, with no other abnormalities of the neuro-respiratory system. Because of respiratory distress soon after birth, patients must be intubated and ventilated for a long time. This disorder may be associated with other symptoms of neurocristopathy (Hirschsprung disease, neuroblastoma, neuroganglioma) and other abnormalities of the autonomic nervous system (vasomotor dysfunctions or ophthalmic abnormalities: abnormal pupils, insufficient convergence, strabismus, or ptosis). We report the original case of a CCHS patient who presented with alternative ptosis of both the right and left eyes and esotropia. The ocular findings should lead to earlier diagnosis and speedier adequate treatment.

[Photocontact dermatitis due to ketoprofen and photosensitization to tetrachlorosalicylanide and to Fenticlor(R)]

BACKGROUND

Photoallergy to ketoprofen and cross reactivity of ketoprofen with diphenylketones are well known; here are some cases of photoreaction to ketoprofen and unusual substances.

PATIENTS AND METHODS

Eleven photoallergic to ketoprofen patients were photo patch tested with Ketum(R), ketoprofen, oxybenzone, tiaprofenic acid, fenofibrate, and also chlorphenesin, sunscreen series, and photobiologists series (without lichen mix and benzocaine). We performed tests at day 0, we irradiated them with UVA at day 2, and control series remained closed. We performed readings at day 3 and 4 according to ICDRG's recommendations.

RESULTS

Nine tested patients had positive reactions to the irradiated tests with no expected allergens: fenticlor (9 cases), halogenated salicylanilides (4 cases), dibenzoylmethane (3 cases) and cinnamate (1 case).

DISCUSSION

The mechanism of these unusual photosensitizations is discussed. These cases show that it is important to test sunscreen series and photobiologists series in patients photoallergic to ketoprofen.

Post-radiation severe xerostomia relieved by pilocarpine: a prospective French cooperative study

BACKGROUND AND PURPOSE

The aim of the study was: (1) to confirm the action of pilocarpine hydrochloride (Salagen) against xerostomia: (2) to correlate the response to dose/volume radiotherapy parameters.

MATERIALS AND METHODS

From June 1995 to February 1996, 156 patients with severe radiation induced xerostomia received pilocarpine hydrochloride orally. IS mg per day with a 5 mg optional increase at S weeks up to a daily dose of 25 mg beyond 9 weeks.

RESULTS

One hundred and forty five patients are fully evaluable. Treatment compliance was 75%. Thirty eight patients (26%) stopped treatment before week 12 for acute intolerance (sweating, nausea, vomiting) or no response. No severe complication occurred. Ninety ses en patients (67%) reported a significant relief of symptoms of xerostomia at 12 weeks. Within 12 weeks, the size of the subgroup ith normal food intake almost doubled (13-24 patients) while the size of the subgroup with (nearly) impossible solid food ingestion decreased by 38% (47 vs. 29 patients). The impact on quality of life was considered important or very important by 77% of the responders.

CONCLUSIONS

No difference was found according to dose/volume radiotherapy parameters suggesting that oral pilocarpine hydrochloride: (1) acts primarily by stimulating minor salivary glands: (2) can be of benefit to patients suffering of severe xerostomia regardless of radiotherapy dose/volume parameters: (3) all responders are identified at 12 weeks.

Use of intraperitoneal pressure, ultrafiltration and purification dwell times for individual peritoneal dialysis prescription in children

Tolerance of peritoneal dialysis is, in a part, dependent on intraperitoneal dialysate volume. Measurement of intraperitoneal pressure (IPP) in cm of water is easy to perform especially with the twin bag Y set (Baxter). Today we use IPP for following surgical catheter implantation (delaying, starting and progressing with peritoneal dialysis) and for optimizing ultrafiltration and purification. Efficiency of peritoneal dialysis is dependent on adequate ultrafiltration (UF) and on adequate purification (solute clearances). These two goals seem apparently conflicting in terms of duration of dwells: short dwell time enhances UF capacity and conversely long dwell time enhances solute clearance. Peritoneal equilibration test (PET) allows an approach to the ultrafiltration time: the point at which the overtime dialysate urea saturation and glucose desaturation curves cross, called APEX time. PET allows also an approach of the purification time: the point at which dialysate (D) to plasma (P) concentration ratios over time are high. Because the value of phosphate as uremic factor of morbidity, we have chosen the time for D/P phosphate equal to 0.6 as a purification phosphate dwell time (PPT). A total of 17 patients were studied, over a five-year period allowing 142 determinations. APEX times (range 18 to 71 min) and PPT (range 105 to 238 min) were spread over a wide distribution. PPT and APEX times were significantly shorter in children younger than 3 years of age than in children older than 10 years of age. PPT were nearly four times longer than APEX times. The knowledge of these conflicting ultrafiltration and purification times should help, in our view, in the individual choice of the PD modality: if UF is the major goal, short dwell times should be used (automatic PD); if purification is the major goal, long dwell times should be used (CAPD); if both are the target goal, tidal PD should be discussed.

[Gitelman syndrome in children: true hypokalemia but false Bartter syndrome]

BACKGROUND

Gitelman's syndrome or familial hypokalemia-hypomagnesemia and Bartter syndrome share some common features but their prognosis is quite different.

CASE REPORT

Four unrelated children, aged 5 to 12 years, were studied because they suffered from muscle cramps and/or abdominal pain. Supportive findings included: hypokalemia (2.1 to 2.9 mmol/l), metabolic alkalosis (31 to 34 mmol/l), hyperkaliuresis (5.8 to 7.1 mmol/kg/day), hypomagnesemia (0.58 to 0.64 mmol/l), hypermagnesuria (0.19 to 0.23 mmol/kg/day), hypocalciuria (0.012 to 0.021 mmol/kg/day). Blood pressure contrasting with high renin activity (19.04 to 20.03 ng/ml/hr) was normal. Chloride fractional excretion after oral water supplementation was only slighty decreased and hypercalciuric response to furosemide administration was not observed. Supplementation with magnesium chloride failed to correct hypomagnesemia while potassium chloride improved hypokalemia.

CONCLUSIONS

Age of onset, tetany manifestations, absence of growth retardation, hypermagnesuria despite, hypomagnesemia, hypocalciuria not improved by furosemide favor the diagnosis of Gitelman's syndrome rather than that of Bartter syndrome initially considered.

Management of fluid overload in infants by tidal peritoneal dialysis: is there a benefit compared with continuous cycling peritoneal dialysis?

Dialysed infants are sometimes characterized by a hyperpermeable peritoneal state. In this situation decreasing dwell time and/or increasing dialysate tonicity are usually proposed to achieve adequate ultrafiltration (UF). We have investigated UF capacity under different peritoneal dialysis modalities in three infants. UF was not obtained with isotonic continuous ambulatory peritoneal dialysis (CAPD), and was only achieved with short dwell times and hypertonic CAPD. For the prescription of automated peritoneal dialysis, a shorter dwell time of hourly sequences is needed, which consequently decreases the phosphate diffusion time. Continuous cycling peritoneal dialysis with sequences of 1 h allowed efficient UF [UF/glucose absorption (UF/G) 4.2 +/- 0.9] but the dialysate/plasma (D/P) phosphate ratio was low (0.47 +/- 0.12). In contrast, tidal peritoneal dialysis gave a better UF/G ratio (6.8 +/- 0.7) without a decrease in the D/P phosphate ratio (0.64 +/- 0.18).

[Water deprivation. An uncommon form of child abuse]

The authors report a case of hypernatremic dehydration following chronic water deprivation and very likely salt load as a form of child abuse in a 2 11/12 year-old girl. This uncommon picture often expresses a severely disturbed relationship between parents and child which has to be considered in the family management.