Cellular Shrinkage Research Articles

Caspase Cascade Proceeds Rapidly After Cytochrome c Release From Mitochondria in Tumor Necrosis Factor-α-Induced Cell Death

The caspase activation cascade and mitochondrial changes are major biochemical reactions in the apoptotic cell death machinery. We attempted to clarify the temporal relationship between caspase activation, cytochrome c release, mitochondrial depolarization, and morphological changes that take place during tumor necrosis factor (TNF)-α-induced cell death in HeLa cells. These reactions were analyzed at the single-cell level with 0.5 – 1 min resolution by using green fluorescent protein (GFP)-variant-derived probes and chemical probes. Cytochrome c release, caspase activation, and cellular shrinkage were always observed in this order within 10 min in all dying cells. This sequence of events was thus considered a critical pathway of cell death. Mitochondrial depolarization was also observed in all dying cells observed, but frequently occurred after caspase activation and cellular shrinkage. Mitochondrial depolarization is therefore likely to be a reaction that does not induce caspase activation and subsequent cellular shrinkage. Mitochondrial changes are important for apoptotic cell death; moreover, cytochrome c release, and not depolarization, is a key reaction related to cell death. In addition, we also found that the apoptotic pathway proceeds only when cells are exposed to TNF-α. These findings suggest that the entire cell death process proceeds rapidly during TNF-α exposure.

Urine Concentration and the Adaptation of Renal Medullary Cells to Hypertonicity

Hypertonicity (hypernatremia) of extracellular fluid causes water movement out of cells, while hypotonicity(hyponatremia) causes water movement into cells, resulting in cellular shrinkage or cellular swelling, respectively. In most part of the body, the osmolality of extracellular fluid is maintaine...

Nutlin-3 Protects Kidney Cells during Cisplatin Therapy by Suppressing Bax/Bak Activation

Nutlins, the newly developed small molecule antagonists of MDM2, activate p53 and induce apoptosis in cancer cells, offering a novel strategy of chemotherapy. Recent studies have further suggested synergistic effects of nutlins with other chemotherapeutic drugs. However, it is unclear whether nutlins increase or decrease the side effects of these drugs in normal non-malignant cells or tissues. Cisplatin is a widely used chemotherapy drug, which has a major side effect of kidney injury. Here we show that Nutlin-3 protected kidney cells against cisplatin-induced apoptosis. The cytoprotective effects of Nutlin-3 were not related to its regulation of p53 or consequent gene expression during cisplatin treatment. Moreover, the protective effects were shown in MDM2-, MDM4-, or p53-deficient cells. On the other hand, Nutlin-3 suppressed mitochondrial events of apoptosis during cisplatin incubation, including Bax activation and cytochrome c release. Nutlin-3 attenuated cisplatin-induced oligomerization of Bax and Bak but not their interactions with Bcl-XL. In isolated mitochondria, Nutlin-3 inhibited cytochrome c release induced by Ca2+, Bim peptide, and recombinant tBid. Importantly, it blocked both Bax and Bak oligomerization under these conditions. Together, the results have uncovered a new pharmacological function of nutlins, i.e. suppression of Bax and Bak, two critical mediators of apoptosis.

Effects of isolation method and pre-treatment with ethylene glycol or raffinose before vitrification on in vitro viability of mouse preantral follicles

Effects of isolation and vitrification protocols on follicular survival after warming were examined. Mouse preantral follicles enzymatically or mechanically isolated from ovaries of 12-day-old mice were exposed either to 2 M ethylene glycol (EG) for 2 or 5 min, or to ascending concentrations (0.15 then 0.3 M) of raffinose for 2 or 5 min each (2-2 and 5-5 min). They were then exposed to a vitrification solution (VS) composed of 6 M EG and 0.3 M raffinose for 0.5, 1, or 2 min before vitrification. Mechanically isolated follicles showed higher survival than enzymatically isolated follicles, regardless of periods of exposure to EG or raffinose and subsequent exposure to VS. After 10 days of culture, follicular growth and maturational ability of oocytes derived from vitrified follicles exposed to 2 M EG for 5 min and to VS for 1 min were higher than those from follicles exposed to raffinose solutions for 2-2 min and to VS for 1 min. Histological evaluation revealed that exposure of preantral follicles to raffinose solutions caused cytoplasmic vacuolation in granulosa cells which could be due to cellular shrinkage during dehydration; whereas, exposure to 2 M EG induced morphological alterations in follicles only to a lesser extent.

Toxicity of Metal Oxide Nanoparticles in Mammalian Cells

Along with existing and emerging use of nanoscale materials, growing concerns have arisen about their unintentional health and environmental impact. The objective of the ongoing study was to assess the toxicity profile of metal oxide nanoparticles proposed for use in industrial production methodology. Metal oxide nanoparticles used in this study included TiO2, ZnO, Fe3O4, Al2O3, and CrO3 with particle sizes ranging from 30 to 45 nm. Cellular morphology, mitochondrial function, membrane leakage of lactate dehydrogenase (LDH), permeability of plasma membrane, and apoptosis were assessed under controlled and exposed conditions (2 to 72 h of exposure). The microscopic studies demonstrated that nanoparticle-exposed Neuro-2A cells (especially ZnO) at doses >100 μg/mL became abnormal in size, displaying cellular shrinkage, and detachment from the surface of flasks. Mitochondrial function decreased significantly in the cells exposed to ZnO at 50 to 100 μg/mL. However, Fe3O4, Al2O3, and TiO2 had no measurable effect on the cells until the concentrations reached greater than 200 μg/mL. LDH leakage significantly increased in the cells exposed to ZnO (50 to 100 μg/mL), while other nanoparticles tested displayed LDH leakage only at higher doses (>200 μg/mL). Flow cytometer tests showed that apoptosis took place in cells exposed to ZnO nanoparticles. More cells became necrotic as the concentrations increased

Electrolytes Disturbances and Seizures

Electrolytes Disturbances and Seizures

Lymphoid apoptosis in Edwardsiella tarda septicemia in tilapia, Oreochromis niloticus

The present study revealed a relationship between the kinetic change of apoptosis and the inflammatory response during experimental intraperitoneal infection with Edwardsiella tarda as a septicemic model. The morphological changes of apoptotic cells including cellular shrinkage, condensed nuclear chromatin, nuclear fragmentation and membrane blebbing were detected by light and transmission electron microscopy. TUNEL and agarose gel electrophoresis confirmed the fragmentation of DNA in the apoptotic cells. Apoptosis was highly detected in lymphoid organs prior to the inflammatory process and gradually decreased after an extensive inflammatory response. Apoptosis in thymus and spleen was extensive and an in vitro study revealed that lymphocytes were the major cell population which underwent apoptosis. The result suggests that E. tarda-induced systemic immunosuppression via lymphocyte apoptosis as determined by suppression of the systemic inflammatory response during an initial step of generalized septicemia.

Mechanisms and Significance of Eryptosis

Suicidal death of erythrocytes (eryptosis) is characterized by cell shrinkage, membrane blebbing, activation of proteases, and phosphatidylserine exposure at the outer membrane leaflet. Exposed phosphatidylserine is recognized by macrophages that engulf and degrade the affected cells. Eryptosis is triggered by erythrocyte injury after several stressors, including oxidative stress. Besides caspase activation after oxidative stress, two signaling pathways converge to trigger eryptosis: (a) formation of prostaglandin E(2) leads to activation of Ca(2+)-permeable cation channels, and (b) the phospholipase A(2)-mediated release of platelet-activating factor activates a sphingomyelinase, leading to formation of ceramide. Increased cytosolic Ca(2+) activity and enhanced ceramide levels lead to membrane scrambling with subsequent phosphatidylserine exposure. Moreover, Ca(2+) activates Ca(2+)-sensitive K(2+) channels, leading to cellular KCl loss and cell shrinkage. In addition, Ca(2+) stimulates the protease calpain, resulting in degradation of the cytoskeleton. Eryptosis is inhibited by erythropoietin, which thus extends the life span of circulating erythrocytes. Eryptosis may be a mechanism of defective erythrocytes to escape hemolysis. Conversely, excessive eryptosis favors the development of anemia. Conditions with excessive eryptosis include iron deficiency, lead or mercury intoxication, sickle cell anemia, thalassemia, glucose 6- phosphate dehydrogenase deficiency, malaria, and infection with hemolysin-forming pathogens.

Apoptotic cell death in the central nervous system of Bufo arenarum tadpoles induced by cypermethrin

Tadpoles of the toad Bufo arenarum treated with cypermethrin (CY) at concentrations above 39 mug CY/L showed dose-dependent apoptotic cell death in immature cells of the central nervous system as demonstrated by morphometric analysis, the TUNEL method, and DNA fragmentation assay. Light-and electron-microscopic studies showed structural alterations in the intermediate and marginal layers of the brain. Immature cerebral tissue showed cellular shrinkage, nuclear fragmentation and increase of intercellular spaces. In this study we demonstrated high toxicity of CY to larval stages of Bufo arenarum. Our results show that doses lower than those used in routine insecticide applications can cause massive apoptosis in the immature cells of the central nervous system. These results coincide with our previous studies in Physalaemus biligonigerus, confirming the severe toxic effects of CY to the central nervous system of anuran species from Argentina. This may increase the mortality index in wild animals and contribute to the loss of biodiversity in our agroecosystems. We postulate that CY induces apoptosis in central nervous system cells of Bufo arenarum tadpoles by specific neurotoxic mechanisms.

Differential effects of x-irradiation on immature and mature hippocampal neurons in vitro

X-irradiation to neuronal progenitor cells causes brain dysfunctions, such as a mental retardation, in adulthood. However, little has been known about the degree of radiosensitivity of neurons in the developmental stages at which they are most vulnerable. In this study we compared the effect of irradiation on mature neurons with that on immature neurons. Primary dissociated neuronal cultures were prepared from fetal rat hippocampi of embryonic day 18. X-irradiations were performed on the cultured cells at 7 or 21 days in vitro (DIV), and the cells were fixed at 12 or 24 h after irradiation. Then the cells were stained with 4′,6-diamidino-2-phenylindole (DAPI) or terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The apoptotic changes were measured quantitatively by nuclear pyknosis and DNA fragmentation—both characteristic morphological changes of apoptosis. Light microscopy with differential interference contrast showed that 30 Gy of irradiation increased cellular shrinkage in 7-DIV neurons but not in 21-DIV neurons. Quantitative analysis using DAPI imaging showed that 30 Gy of irradiation significantly enhanced pyknotic changes in 7-DIV neurons after 24 h. In contrast, this irradiation did not enhance any pyknotic changes in 21-DIV neurons after 24 h. Further TUNEL staining also showed that the irradiation did not enhance any DNA fragmentation in nuclei of 21-DIV neurons after 24 h. Hence, we showed that the radiosensitivity of 21-DIV postmitotic neurons was significantly lower than that of 7-DIV neurons, indicating that the susceptibility of such neurons depends on their developmental stage.

Proapoptotic activity of Ukrain is based on Chelidonium majusL. alkaloids and mediated via a mitochondrial death pathway

BackgroundThe anticancer drug Ukrain (NSC-631570) which has been specified by the manufacturer as semisynthetic derivative of the Chelidonium majus L. alkaloid chelidonine and the alkylans thiotepa was reported to exert selective cytotoxic effects on human tumour cell lines in vitro. Few clinical trials suggest beneficial effects in the treatment of human cancer. Aim of the present study was to elucidate the importance of apoptosis induction for the antineoplastic activity of Ukrain, to define the molecular mechanism of its cytotoxic effects and to identify its active constituents by mass spectrometry.MethodsApoptosis induction was analysed in a Jurkat T-lymphoma cell model by fluorescence microscopy (chromatin condensation and nuclear fragmentation), flow cytometry (cellular shrinkage, depolarisation of the mitochondrial membrane potential, caspase-activation) and Western blot analysis (caspase-activation). Composition of Ukrain was analysed by mass spectrometry and LC-MS coupling.ResultsUkrain turned out to be a potent inducer of apoptosis. Mechanistic analyses revealed that Ukrain induced depolarisation of the mitochondrial membrane potential and activation of caspases. Lack of caspase-8, expression of cFLIP-L and resistance to death receptor ligand-induced apoptosis failed to inhibit Ukrain-induced apoptosis while lack of FADD caused a delay but not abrogation of Ukrain-induced apoptosis pointing to a death receptor independent signalling pathway. In contrast, the broad spectrum caspase-inhibitor zVAD-fmk blocked Ukrain-induced cell death. Moreover, over-expression of Bcl-2 or Bcl-xL and expression of dominant negative caspase-9 partially reduced Ukrain-induced apoptosis pointing to Bcl-2 controlled mitochondrial signalling events.However, mass spectrometric analysis of Ukrain failed to detect the suggested trimeric chelidonine thiophosphortriamide or putative dimeric or monomeric chelidonine thiophosphortriamide intermediates from chemical synthesis. Instead, the Chelidonium majus L. alkaloids chelidonine, sanguinarine, chelerythrine, protopine and allocryptopine were identified as major components of Ukrain.Apart from sanguinarine and chelerythrine, chelidonine turned out to be a potent inducer of apoptosis triggering cell death at concentrations of 0.001 mM, while protopine and allocryptopine were less effective. Similar to Ukrain, apoptosis signalling of chelidonine involved Bcl-2 controlled mitochondrial alterations and caspase-activation.ConclusionThe potent proapoptotic effects of Ukrain are not due to the suggested "Ukrain-molecule" but to the cytotoxic efficacy of Chelidonium majus L. alkaloids including chelidonine.

Synchronous progression of calcium transient-dependent beating and sarcomere destruction in apoptotic adult cardiomyocytes

During early apoptosis, adult cardiomyocytes show unusual beating, suggesting possible participation of abnormal Ca(2+) transients in initiation of apoptotic processes in this cell type. Simultaneously with the beating, these cells show dynamic structural alteration resulting from cytoskeletal disintegration that is quite rapid. Because of the specialized structure and extensive cytoskeleton of cardiomyocytes, we hypothesized that its degradation in so short a time would require a particularly efficient mechanism. To better understand this mechanism, we used serial video microscopy to observe beta-adrenergic stimulation-induced apoptosis in isolated adult rat cardiomyocytes while simultaneously recording intracellular Ca(2+) concentration and cell length. Trains of Ca(2+) transients and corresponding rhythmic contractions and relaxations (beating) were observed in apoptotic cells. Frequencies of Ca(2+) transients and beating gradually increased with time and were accompanied by cellular shrinkage. As the cells shrank, amplitudes of Ca(2+) transients declined and diastolic intracellular Ca(2+) concentration increased until the transients were lost. Beating and progression of apoptosis were significantly inhibited by antagonists against the L-type Ca(2+) channel (nifedipine), ryanodine receptor (ryanodine), inositol 1,4,5-trisphosphate receptor (heparin), sarco(endo)plasmic Ca(2+)-ATPase (thapsigargin), and Na(+)/Ca(2+) exchanger (KB-R7943). Electron-microscopic examination of beating cardiomyocytes revealed progressive breakdown of Z disks. Immunohistochemical analysis and Western blot confirmed that disappearance of Z disk constituent proteins (alpha-actinin, desmin, and tropomyosin) preceded degradation of other cytoskeletal proteins. It thus appears that, in adult cardiomyocyte apoptosis, Ca(2+) transients mediate apoptotic beating and efficient sarcomere destruction initiated by Z disk breakdown.

Studying Mechanisms of Eryptosis

Cellular stress leads to activation of erythrocyte cation channels with subsequent Ca2+ entry and stimulates a sphingomyelinase with subsequent formation of ceramide. Both signaling molecules then activate the death program of erythrocytes (eryptosis) which is characterized by phosphatidylserine exposure, cellular shrinkage, membrane blebbing and activation of death-inducing proteases. Some of the mediators accounting for activation of the erythrocyte death machinery, i. e. prostaglandin E2 (PGE2) and platelet activating factor (PAF), have been described and the respective signaling cascades disclosed. The present article outlines and discusses the methods which have been used to analyze erythrocyte death pathways. Furthermore, some of the pathophysiological implications of eryptosis signaling are delineated and the methods to screen for eryptosis defects in those conditions are presented. Needless to say that further research will be required to fully understand the mechanisms leading to suicidal red blood cell death and to elucidate the role of eryptosis during anemic complications.

Cell shrinkage as a signal to apoptosis in NIH 3T3 fibroblasts

Cell shrinkage is a hallmark of the apoptotic mode of programmed cell death, but it is as yet unclear whether a reduction in cell volume is a primary activation signal of apoptosis. Here we studied the effect of an acute elevation of osmolarity (NaCl or sucrose additions, final osmolarity 687 mosmol l(-1)) on NIH 3T3 fibroblasts to identify components involved in the signal transduction from shrinkage to apoptosis. After 1.5 h the activity of caspase-3 started to increase followed after 3 h by the appearance of many apoptotic-like bodies. The caspase-3 activity increase was greatly enhanced in cells expressing a constitutively active G protein, Rac (RacV12A3 cell), indicating that Rac acts upstream to caspase-3 activation. The stress-activated protein kinase, p38, was significantly activated by phosphorylation within 30 min after induction of osmotic shrinkage, the phosphorylation being accelerated in fibroblasts overexpressing Rac. Conversely, the activation of the extracellular signal-regulated kinase (Erk1/2) was initially significantly decreased. Subsequent to activation of p38, p53 was activated through serine-15 phosphorylation, and active p53 was translocated from the cytosol to the nucleus. Inhibition of p38 in Rac cells reduced the activation of both p53 and caspase-3. After 60 min in hypertonic medium the rate constants for K+ and taurine efflux were increased, particular in Rac cells. We suggest the following sequence of events in the cell shrinkage-induced apoptotic response: cellular shrinkage activates Rac, with activation of p38, followed by phosphorylation and nuclear translocation of p53, resulting in permeability increases and caspase-3 activation.

In vitro toxicity of nanoparticles in BRL 3A rat liver cells

This study was undertaken to address the current deficient knowledge of cellular response to nanosized particle exposure. The study evaluated the acute toxic effects of metal/metal oxide nanoparticles proposed for future use in industrial production methods using the in vitro rat liver derived cell line (BRL 3A). Different sizes of nanoparticles such as silver (Ag; 15, 100 nm), molybdenum (MoO 3; 30, 150 nm), aluminum (Al; 30, 103 nm), iron oxide (Fe 3O 4; 30, 47 nm), and titanium dioxide (TiO 2; 40 nm) were evaluated for their potential toxicity. We also assessed the toxicity of relatively larger particles of cadmium oxide (CdO; 1 μm), manganese oxide (MnO 2; 1–2 μm), and tungsten (W; 27 μm), to compare the cellular toxic responses with respect to the different sizes of nanoparticles with different core chemical compositions. For toxicity evaluations, cellular morphology, mitochondrial function (MTT assay), membrane leakage of lactate dehydrogenase (LDH assay), reduced glutathione (GSH) levels, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) were assessed under control and exposed conditions (24 h of exposure). Results showed that mitochondrial function decreased significantly in cells exposed to Ag nanoparticles at 5–50 μg/ml. However, Fe 3O 4, Al, MoO 3 and TiO 2 had no measurable effect at lower doses (10–50 μg/ml), while there was a significant effect at higher levels (100–250 μg/ml). LDH leakage significantly increased in cells exposed to Ag nanoparticles (10–50 μg/ml), while the other nanoparticles tested displayed LDH leakage only at higher doses (100–250 μg/ml). In summary the Ag was highly toxic whereas, MoO 3 moderately toxic and Fe 3O 4, Al, MnO 2 and W displayed less or no toxicity at the doses tested. The microscopic studies demonstrated that nanoparticle-exposed cells at higher doses became abnormal in size, displaying cellular shrinkage, and an acquisition of an irregular shape. Due to toxicity of silver, further study conducted with reference to its oxidative stress. The results exhibited significant depletion of GSH level, reduced mitochondrial membrane potential and increase in ROS levels, which suggested that cytotoxicity of Ag (15, 100 nm) in liver cells is likely to be mediated through oxidative stress.

Hypoxic preconditioning attenuated in kainic acid-induced neurotoxicity in rat hippocampus

The neuroprotective effect of hypoxic preconditioning on kainate (KA)-induced neurotoxicity, including apoptosis and necrosis, was investigated in rat hippocampus. Female Wistar–Kyoto rats were subjected to 380 mm Hg in an altitude chamber for 15 h/day for 28 days. Intrahippocampal infusion of KA was performed in chloral hydrate anesthetized rats, which acutely elevated 2,3-dihydroxybenzoic acid levels in normoxic rats. Seven days after the infusion, KA increased lipid peroxidation in the infused hippocampus and resulted in hippocampal CA3 neuronal loss. A 4-week hypoxic preconditioning attenuated KA-induced elevation in hydroxyl radical formation and lipid peroxidation as well as KA-induced neuronal loss. The effects of hypoxic preconditioning on KA-induced apoptosis and necrosis were investigated further. Two hours after KA infusion, cytosolic cytochrome c content was increased in the infused hippocampus. Twenty-four hours after KA infusion, pyknotic nuclei, cellular shrinkage, and cytoplasmic disintegration, but not TUNEL-positive staining, were observed in the CA3 region of hippocampus. Forty-eight hours after KA infusion, both DNA smear and DNA fragmentation were demonstrated in the infused hippocampus. Furthermore, TUNEL-positive cells, indicative of apoptosis, in the infused hippocampus were detected 72 h after KA infusion. Hypoxic pretreatment significantly reduced necrotic-like events in the KA-infused hippocampus. Moreover, hypoxic preconditioning attenuated apoptosis induced by KA infusion, including elevation in cytosolic cytochrome c content, TUNEL-positive cells, and DNA fragmentation. Our data suggest that hypoxic preconditioning may exert its neuroprotection of KA-induced oxidative injuries via attenuating both apoptosis and necrosis in rat hippocampus.

Optimal Processing Method to Obtain Four-color Confocal Fluorescent Images of the Cytoskeleton and Nucleus in Three-dimensional Chondrocyte Cultures

Tissue engineering of articular cartilage requires accurate imaging of the chondrocyte cytoskeleton. Past studies have applied various fixation and permeabilization protocols without optimization of parameters. In this study, we have examined procedures using glutaraldehyde and paraformaldehyde as fixatives and Triton X-100 and Octyl-POE as permeabilizing detergents. A four-color fluorescence confocal method was developed to simultaneously image actin, tubulin, vimentin, and the nucleus. We found optimal preservation and morphology of the chondrocyte cytoskeleton after simultaneous fixation and permeabilization with glutaraldehyde and Triton X-100. These images displayed less cellular shrinkage and higher-resolution filamentous structures than with paraformaldehyde or when permeabilization followed fixation.

Degenerative mineralization in the fibrous capsule of silicone breast implants

The formation of a fibrous capsule made of long collagen fibers surrounding breast implants represents an unavoidable phenomenon as the patient's reaction to the presence of a foreign body. Depending upon the size and shape of the implants and the chemicals percolating through the shell, this fibrous capsule is continuously remodeled. The compaction of the foreign debris in the vicinity of the silicone shell is followed by the loss of cellular activity, shrinkage and necrosis. Calcification is the ultimate step. These phenomena were illustrated in the analysis of 18 explanted breast prostheses after 20 or more years of implantation. The degenerative mineralization was shown in scanning electron microscopy and light microscopy. The minerals proved to be bone-like hydroxyapatite by X-ray diffraction and Solid State NMR analysis. Whatever the characteristics of any sophisticated new model of breast implant, phenomenon of mineralization might be minimized but it is very unlikely that it would be totally eliminated.

Ultrastructural studies on dengue virus type 2 infection of cultured human monocytes

BackgroundEarly interaction of dengue virus and monocyte/macrophages could be an important feature for virus dissemination after its initial entry via the mosquito vector. Since ultrastructural analysis of this interaction has not been reported, dengue type 2 (DEN2) virus-infected human monocyte cultures were studied at 1, 2, 4 and 6 hours after infection.ResultsTypical dengue particles and fuzzy coated viral particles were 35 to 42 nm and 74 to 85 nm respectively. Viruses were engulfed by phagocytosis and macropicnocytosis leading to huge vacuoles and phagosomes inside the monocytes. Interaction of monocytes with DEN2 virus induced apoptosis, characterized by nuclear condensation and fragmentation, cellular shrinkage, blebbing and budding phenomena and phagocytosis of apoptotic cells by neighboring monocytes. This finding was confirmed by TUNEL. Ultrastructural features associated to DEN2 virus replication were not observed.ConclusionThese data suggest that clearance of the virus by monocytes and cellular death are the main features during the initial interaction of DEN2 virus and monocytes and this could be important in the rapid elimination of the virus after infection by mosquito vector.

Integrated approach on solar drying, pilot convective drying and microstructural changes

Solar drying of foods is an old technique, still used nowadays. Nevertheless, the mathematical approach of the complex phenomena involved is not completely integrated. Drawbacks appear in modelling heat transport, specially related to the huge variability of meteorological factors. The great dependence of the heat and mass transfer model parameters on water content is also frequently forgotten. Macroscopic changes (e.g. shrinkage) that occur during drying processes, are usually not considered in mass transfer equations, also affecting the predictive ability of the models. The objective of this work was to develop the mathematical basis and considerations for integrating heat and mass transfer phenomena, taking into consideration macroscopic changes and their correlation to changes at microscopic level (e.g. cellular shrinkage), that might occur during solar drying of grapes.